JP2008165959A - Optical disc apparatus, optical disc discrimination method, program, and integrated circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an optical disk device in which discrimination of disks of a plurality of standards can be executed stably and in a short time without destroying recording information on a loaded disk. <P>SOLUTION: In this optical disk 100, a first laser beam mixed by a laser beam mix separation part and a second laser beam of which the wavelength is shorter than the first laser beam are projected to the optical disk 1 simultaneously. Since focus distance of an objective lens 29 for the first laser beam is longer than focus distance for the second laser beam and the first laser beam having longer wavelength is projected first, risk of destroying an information plane of the optical disk 1 can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a consumer optical disc apparatus.

In an apparatus that records and reproduces a plurality of disks such as CDs and DVDs that use different laser wavelengths, it is necessary to determine the type of the loaded disk.
An infrared laser with a wavelength of about 780 [nm] is used for CD recording and reproduction, and a red laser with a wavelength of about 650 [nm] is used for recording and reproduction of a DVD. If the CD is irradiated with a DVD laser having a wavelength shorter than that of the CD laser, there is a problem that the recorded information is destroyed because the CD recording film absorbs the laser.
As an example of disc discrimination to avoid the above problem, first, the infrared laser having the longest wavelength is irradiated, and it is discriminated whether or not the loaded disc is a CD without performing focus control and tracking control. If not, irradiate a red laser with a short wavelength and determine whether the loaded disc is a DVD without applying focus control and tracking control to avoid destruction of recorded information by the short wavelength laser. An apparatus has been proposed (see, for example, Patent Document 1).

The operation of the conventional optical disc apparatus will be described with reference to FIGS.
FIG. 16 is a block diagram showing a conventional disc discrimination configuration.
The optical head 1610 mainly includes an infrared laser light source 11, an infrared laser light beam splitter 13, an infrared laser light front light monitor 15, a red laser light source 12, a red laser light beam splitter 14, and a red laser light. The front light monitor 16, the irradiation beam splitter 20, the objective lens 29, the focus actuator 34, the detector beam splitter 21, the infrared laser light detector 23, and the red laser light detector 24 are configured.
The infrared laser light source 11 irradiates infrared laser light having a wavelength of about 780 [nm]. The infrared laser beam splitter 13 splits the infrared laser beam into the irradiation beam splitter 20 and the infrared laser beam front light monitor 15. The infrared laser beam front light monitor 15 detects the output power of the irradiated infrared laser beam.

The red laser light source 12 emits red laser light having a wavelength of about 650 [nm]. The red laser beam splitter 14 splits the red laser beam into the irradiation beam splitter 20 and the red laser beam front light monitor 16. The red laser light front light monitor 16 detects the output power of the irradiated red laser.
The red laser beam and the infrared laser beam that have been split by the irradiation beam splitter 20 are reflected by the irradiation beam splitter 20 in the direction of the objective lens 29 and converged on the information surface of the optical disc 1 by the objective lens 29. The red laser light and the infrared laser light reflected by the optical disk 1 pass through the irradiation beam splitter 20, and the red laser light passes through the detector beam splitter 21 and is irradiated on the red laser light detector 24, and the infrared laser light. The laser light is irradiated to the infrared laser light detector 23 by the detector beam splitter 21.

The laser controller (laser controller) 53 is configured so that the red laser light output level detected by the red laser light front light monitor 16 and the infrared laser light output level detected by the infrared laser light front light monitor 15 are predetermined. A reproduction light emission drive signal that gives a reproduction laser light output level of 2 is output to an LDD (Laser Diode Driver) 40. That is, the reproduction light emission drive signal output from the laser controller (laser control unit) 53 is controlled so that the red laser light output level and the infrared laser light output level become the predetermined reproduction laser light output level.
The LDD 40 mainly includes a reproduction light emission drive signal gain amplifier 42 and a light emission laser selection SW 41.
The reproduction light emission drive signal gain amplifier 42 amplifies the reproduction light emission drive signal. The LDD 40 outputs a signal for laser driving amplified by the reproduction light emission driving signal gain amplifier 42 to the infrared laser light source 11 or the red laser light source 12.

The disc discriminating controller (disc discriminating unit) 50 outputs a switching control signal that determines whether the LDD 40 outputs a signal for driving the laser to the infrared laser light source 11 or the red laser light source 12. The light emission laser selection SW 41 of the LDD 40 outputs a signal for driving the laser output from the reproduction light emission drive signal gain amplifier 42 in accordance with the switching control signal output from the disc determination unit 50. Output to. That is, the output destination of the signal for driving the laser output from the reproduction light emission drive signal gain amplifier 42 is switched to the infrared laser light source 11 or the red laser light source 12 based on the switching control signal output from the disc determination unit 50. It is done.
The disc discrimination controller (disc discriminator) 50 outputs a drive signal for driving the objective lens 29 up and down. Here, “up and down driving” means that the distance between the objective lens 29 and the optical disc 1 becomes small when the optical axis direction of the objective lens 29 and the normal direction of the information recording surface of the optical disc 1 are substantially matched. Alternatively, the driving is performed so as to increase, and the driving is not necessarily limited to the driving in the “up and down” direction. This is the same for the following description.

The servo signal generation circuit (servo signal generation unit) 56 generates and outputs a servo signal from the output from the infrared laser light detector 23 or the red laser light detector 24. The disc discrimination controller (disc discriminating unit) 50 discriminates the type of disc loaded in the optical disc apparatus 900 based on the servo signal generated by the servo signal generation circuit (servo signal generation unit) 56.
Next, with reference to FIG. 17, a procedure for disc determination when the loaded disc is a CD will be described.
FIG. 17 shows the objective lens position and the focus error signal when the objective lens 29 is driven in a state where infrared laser light is emitted from the CD.
FIG. 17 (1) is a diagram showing the relationship between time and the position of the objective lens 29 with the horizontal axis being time and the vertical axis being the position of the objective lens 29. Specifically, FIG. 17A shows a position signal of the objective lens 29 when infrared laser light is emitted and the objective lens 29 is brought close to the CD.

FIG. 17B is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 17B shows that the servo signal generation circuit (servo signal generation unit) 56 for infrared laser light when infrared laser light is emitted and the objective lens 29 is brought close to the CD. A focus error signal generated from the output of the detector 23 is shown.
At the disc discrimination start timing T37, the disc discrimination controller (disc discriminator) 50 starts the disc discrimination operation. In order to prevent the recorded information on the information surface of the CD from being destroyed by the red laser light, the disc discrimination controller (disc discriminator) 50 emits light from the LDD 40 so that the LDD 40 outputs laser drive to the infrared laser light source 11. By switching the laser selection SW 41, infrared laser light is first emitted. Further, the disc discrimination controller (disc discriminator) 50 drives the focus actuator 34 to raise the position of the objective lens 29. In other words, the focus actuator 34 is driven by the control signal output from the disc discrimination controller (disc discriminator) 50 so that the position of the objective lens 29 is raised (the distance between the objective lens 29 and the disc 1 is reduced). The

At timing T38, the focus of the infrared laser light passes through the surface of the CD (the surface of the CD facing the objective lens 29), and a focus error signal is generated based on the signal from the infrared laser light detector 23 when passing. can get. That is, a focus error signal having a waveform as indicated by W221 in FIG. 17 is output in the vicinity of timing T38.
At timing T39, the focal point of the infrared laser light passes through the information surface (the surface on which information is recorded) of the CD, and a focus error signal is obtained based on the signal from the infrared laser light detector 23 at the time of passage. That is, a focus error signal having a waveform as indicated by W222 in FIG. 17 is output in the vicinity of timing T39. When the amplitude of the focus error signal obtained at this time exceeds a certain level L11, the disc discrimination controller (disc discriminator) 50 determines that the disc loaded in the optical disc apparatus 900 is a CD.
If it is determined that the loaded disk is a CD, the disk determination controller (disk determination unit) 50 ends the disk determination operation.

Next, the disc discrimination procedure when the disc loaded is a DVD will be described with reference to FIG.
FIG. 18 shows the relationship between the objective lens position and the output of the focus error signal when the objective lens 29 is driven with the infrared laser light emitted from the DVD, and the red laser light emitted. FIG. 4 is a diagram illustrating a relationship between an objective lens position and a focus error signal when the objective lens 29 is driven.
FIG. 18 (1) is a diagram showing the relationship between time and the position of the objective lens 29, where the horizontal axis is time and the vertical axis is the position of the objective lens 29. Specifically, FIG. 18A shows a position signal of the objective lens 29 (position signal before timing T43) when the infrared laser light is emitted and the objective lens 29 approaches the DVD, and the red laser light. Is a position signal of the objective lens 29 (position signal after timing T43) when the objective lens 29 is brought close to the DVD.

FIG. 18B is a diagram illustrating the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 18B shows that the servo signal generation circuit (servo signal generation unit) 56 detects the infrared laser light when the objective lens 29 is brought close to the DVD by emitting infrared laser light. 23 shows a focus error signal generated from the output of No. 23.
FIG. 18 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 18 (3) shows that the servo signal generation circuit (servo signal generation unit) 56 of the red laser beam detector 24 emits red laser beam and brings the objective lens 29 close to the DVD. A focus error signal generated from the output is shown.

FIG. 18 (4) is a diagram showing a state of whether infrared laser light or red laser light is emitted with the horizontal axis as time.
At the disc discrimination start timing T40, the disc discrimination controller (disc discriminator) 50 starts the disc discrimination operation. In order to prevent the recorded information on the information surface of the CD from being destroyed by the red laser light, the disc discriminating controller (disc discriminating unit) 50 causes the LDD 40 to output a signal for laser driving to the infrared laser light source 11. The infrared laser light is first emitted from the infrared laser light source by switching the light emitting laser selection SW 41 of the LDD 40. Further, the disc discriminating controller (disc discriminating unit) 50 gives a drive signal to the focus actuator 34 to raise the position of the objective lens 29 (moves the objective lens 29 in the direction in which the distance from the optical disc 1 is reduced).

At timing T41, the focus of the infrared laser passes through the surface of the DVD (the surface of the DVD facing the objective lens 29), and a focus error signal is obtained based on the signal from the infrared laser light detector 23 when passing. It is done. That is, a focus error signal having a waveform as indicated by W231 in FIG. 18 is output in the vicinity of timing T41.
At timing T42, the focal point of the infrared laser passes through the information surface (the surface on which information is recorded) of the DVD, and a focus error signal is obtained based on the signal from the infrared laser light detector 23 at the time of passage. That is, a focus error signal having a waveform as indicated by W232 in FIG. 18 is output in the vicinity of timing T42. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L11, the disc discrimination controller (disc discriminator) 50 continues the disc discrimination operation.

The disc discrimination controller (disc discriminator) 50 continues to raise the objective lens 29 (in order to keep the objective lens 29 moving in a direction in which the distance from the optical disc 1 becomes smaller), so that the objective lens 29 is preset in timing T43. The specified position limit is reached. Therefore, the disc discriminating controller (disc discriminating unit) 50 stops raising the objective lens 29, lowers the objective lens 29 (moves the objective lens 29 in the direction of increasing the distance from the optical disc 1), and resets the position (FIG. 18 (FIG. 18). Return to the position corresponding to the position at timing T40 of 1).
At this time, the disc discrimination controller (disc discriminator) 50 determines that the optical disc 1 loaded in the optical disc apparatus 900 is not a CD. In this state, since there is no risk of the information recorded on the information surface of the CD being destroyed by the red laser, the disc discrimination controller (disc discriminator) 50 outputs a signal for the LDD 40 to drive the laser to the red laser light source 12. As described above, the light emitting laser selection SW 41 of the LDD 40 is switched. As a result, red laser light is emitted from the red laser light source 12. Since it is known that the optical disc 1 loaded in the optical disc apparatus 900 is not a CD, even if the optical disc 1 is irradiated with red laser light, the recorded information on the optical disc 1 is not destroyed. Further, the disc discriminating controller (disc discriminating unit) 50 gives a drive signal to the focus actuator 34 to raise the position of the objective lens 29 (moves the objective lens 29 in the direction in which the distance from the optical disc 1 is reduced).

At timing T44, the focus of the red laser passes through the surface of the DVD (the surface of the DVD facing the objective lens 29), and a focus error signal is obtained based on the signal from the detector 24 for red laser light when passing. That is, a focus error signal having a waveform as indicated by W233 in FIG. 18 is output in the vicinity of timing T44.
At timing T45, the focal point of the red laser light passes through the DVD information surface, and a focus error signal is obtained based on the signal from the red laser light detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W234 in FIG. 18 is output in the vicinity of timing T45. When the amplitude of the focus error signal obtained at this time exceeds a certain level L12, the disc discrimination controller (disc discriminator) 50 determines that the disc loaded in the optical disc apparatus 900 is a DVD.

If it is determined that the loaded disk is a DVD, the disk determination controller (disk determination unit) 50 ends the disk determination operation.
JP-A-11-176073

However, in this apparatus, when the types of discs to be recorded / reproduced increase and the types of laser wavelengths (laser light wavelengths) used also increase, the time required for discriminating the disc type increases accordingly.
For example, the case of a device that records and reproduces a Blu-ray disc (hereinafter also referred to as “BD”), HD-DVD, DVD, and CD will be described. In such an apparatus, blue laser light having a wavelength of about 405 [nm] is used for recording and reproduction of Blu-ray discs and HD-DVDs. In such an apparatus, in order to avoid destruction of the information surface on the optical disc, light is emitted in order from a laser having a long wavelength. First, infrared laser light is irradiated, and the loaded optical disc is a CD. It is determined whether or not there is. Next, red laser light is irradiated to determine whether or not the loaded optical disk is a DVD. Finally, the blue laser light is irradiated to determine whether the loaded optical disk is a Blu-ray disk or an HD-DVD.

In such an apparatus, in the worst case, the type of the loaded disc cannot be discriminated unless the discriminating process is performed three times. Therefore, there is a problem that it takes a long time to start recording or reproduction after the disc is loaded.
The present invention has been made to solve the above-described problems, and performs discriminating between a plurality of standard discs safely and in a short time without destroying recorded information on the loaded disc. It is an object of the present invention to realize an optical disc device that can be used.

In the optical disk apparatus of the present invention, the function of switching the recording light emission drive signal used for recording laser emission to be used for reproduction laser emission inside the LDD and the resolution of the gain for amplifying the recording light emission drive signal are also equivalent to the reproduction light emission drive signal gain. It is characterized by having things.
Furthermore, the wavelength of the laser beam irradiated from the same objective lens is freely selected.
Further, the present invention is characterized in that laser beams having three or more wavelengths are irradiated from the same objective lens.
Further, by discriminating not the type of disc but the type of information surface on the disc, the substrate thickness from the surface of the optical disc 1 to the information surface (the thickness of the substrate) is substantially the same and the corresponding laser wavelengths are different. A disc having a plurality of information planes on one disc is discriminated.

Further, the laser output (laser beam output level) to be irradiated is set to a low output (low output level).
Furthermore, high-frequency superposition is performed on the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
Further, the present invention is characterized in that a combination of a light emission drive signal and a laser light source that emits light is freely selected.
In addition, an objective lens that connects the focal positions of the red laser beam and the blue laser beam converged by the same objective lens to the far side in the normal direction (the optical axis direction of the objective lens) with respect to the objective lens. It is characterized in that the position of the objective lens at the time of disc discriminating operation used is moved in the direction approaching the vicinity of the surface of the optical disc (the surface of the optical disc on the side facing the objective lens).

Furthermore, an objective lens that connects the focal positions of the red laser beam and the blue laser beam converged by the same objective lens to the side closer to the normal direction (the optical axis direction of the objective lens) of the red laser beam with respect to the objective lens. It is characterized in that the position of the objective lens during the disc discrimination operation is moved away from the vicinity of the surface of the optical disc (the surface of the optical disc on the side facing the objective lens).
Furthermore, the wavelength of the laser beam irradiated from the same objective lens is freely selected.
Further, the present invention is characterized in that laser beams having three or more wavelengths are irradiated from the same objective lens.
Further, it is characterized in that not the type of the disc but the type of information surface on the disc is discriminated.

Further, the laser output (laser beam output level) to be irradiated is set to a low output (low output level).
Furthermore, high-frequency superposition is performed on the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
Further, the present invention is characterized in that a combination of a light emission drive signal and a laser light source that emits light is freely selected.
Further, the focal positions of the red laser beam and the blue laser beam converged by the two objective lenses are connected to the far side in the normal direction (the optical axis direction of the objective lens) with respect to the objective lens. A drive difference is provided between both objective lenses.
Furthermore, the wavelength of the laser light emitted from the two objective lenses is freely selected.

Furthermore, the present invention is characterized in that laser light having three or more wavelengths is emitted from two objective lenses.
Further, the focal positions of the red laser beam and the blue laser beam converged by separate objective lenses are connected to the side closer to the normal direction (the optical axis direction of the objective lens) with respect to the objective lens. A drive difference is provided between both objective lenses, and the position of the objective lens during the disc discrimination operation is moved away from the vicinity of the surface of the optical disc (the surface of the optical disc on the side facing the objective lens).
Further, it is characterized in that not the type of the disc but the type of information surface on the disc is discriminated.
Further, the laser output (laser beam output level) to be irradiated is set to a low output (low output level).

Furthermore, high-frequency superposition is performed on the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
Further, the present invention is characterized in that a combination of a light emission drive signal and a laser light source that emits light is freely selected.
In addition, a low NA (Numerical Aperture) objective lens is used in which the focal point of the infrared laser light is farther in the normal direction (optical axis direction of the objective lens) than the focal point of the red laser light. In addition, the discriminating process of Blu-ray disc, DVD and CD is performed, and the discriminating process of HD-DVD is thereafter performed.
In addition, a low-NA objective lens that focuses on the side closer to the normal direction (the optical axis direction of the objective lens) than the focal point of the red laser light is used to discriminate the disc. The position of the low NA objective lens during operation is moved away from the vicinity of the surface of the optical disc (the surface of the optical disc on the side facing the objective lens).

Further, the present invention is characterized in that the LDD configuration is such that a combination of a light emission drive signal and a laser light source used for laser light emission can be freely selected.
Further, it is characterized in that not the type of the disc but the type of information surface on the disc is discriminated.
Further, the laser output (laser beam output level) to be irradiated is set to a low output (low output level).
Furthermore, high-frequency superposition is performed on the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
The first invention includes a first laser light source, a second laser light source, a laser light mixing / separating unit, an objective lens, an objective lens driving unit, a first laser light detecting unit, and a second laser light detecting unit. The optical disk device includes a servo signal generation unit and a disk determination unit.

  The first laser light source irradiates the first laser light. The second laser light source irradiates a second laser beam having a shorter wavelength than the first laser beam. The laser beam mixing / separating unit mixes and separates the first laser beam and the second laser beam. The objective lens simultaneously irradiates the optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing / separating unit. The objective lens drive unit varies the distance between the objective lens and the optical disc by driving the objective lens to and from the optical disc. The first laser beam detector detects the intensity of the first laser beam reflected from the optical disk. The second laser light detection unit detects the intensity of the second laser light reflected from the optical disk. The servo signal generation unit generates a first laser light detection signal corresponding to the detection result of the first laser light detection unit and a second laser light detection signal corresponding to the detection result of the second laser light detection unit. The disc discriminating unit discriminates the type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal.

In this optical disc apparatus, the first laser beam and the second laser beam mixed by the laser beam mixing / separating unit can be simultaneously irradiated onto the optical disc, so that the type of the disc loaded in the optical disc apparatus can be quickly determined. be able to.
2nd invention is 1st invention, Comprising: The objective lens has the focal distance about 1st laser beam longer than the focal distance about 2nd laser beam, and performs the operation | movement which discriminate | determines the kind of disk. In the initial state, the distance between the objective lens and the surface of the optical disk facing the objective lens is set at an initial position, which is a position where the distance is longer than the focal length of the objective lens for the first laser beam. . Then, the objective lens driving unit drives the objective lens in a direction in which the distance between the objective lens and the optical disk is reduced from the initial position. The disc discriminating unit is configured such that the objective lens driving unit drives the first laser beam detection signal and the second laser beam detection signal during a period in which the objective lens is driven in a direction in which the distance between the objective lens and the optical disc decreases from the initial position. Is compared with a predetermined threshold value to determine the type of the optical disc.

In this optical disc apparatus, since the focal length of the objective lens for the first laser beam is longer than the focal length of the second laser beam, the information surface of the optical disc is irradiated with the first laser beam having a long wavelength first. As a result, the risk of destroying the information surface of the optical disk can be avoided. That is, in this optical disc apparatus, the second laser beam having a short wavelength (that is, high energy) is not irradiated onto the information surface of the optical disc first, so that the risk of destroying the information surface of the optical disc can be avoided. it can.
According to a third aspect of the invention, a first laser light source, a second laser light source, a first laser light objective lens, a second laser light objective lens, a first laser light objective lens driving unit, and a second laser are provided. An optical disk device including an optical objective lens drive unit, a first laser light detection unit, a second laser detection unit, a servo signal generation unit, a disk determination unit, and a drive difference addition unit.

  The first laser light source irradiates the first laser light. The second laser light source irradiates a second laser beam having a shorter wavelength than the first laser beam. The first laser light objective lens irradiates the optical disk with the first laser light. The second laser beam objective lens irradiates the optical disk with the second laser beam. The first laser light objective lens drive unit varies the distance between the first laser light objective lens and the optical disk by driving the first laser light objective lens to the perspective of the optical disk. The second laser light objective lens driving unit varies the distance between the second laser light objective lens and the optical disk by driving the second laser light objective lens to and from the optical disk. The first laser beam detector detects the intensity of the first laser beam reflected from the optical disk. The second laser light detection unit detects the intensity of the second laser light reflected from the optical disk. The servo signal generation unit generates a first laser light detection signal corresponding to the detection result of the first laser light detection unit and a second laser light detection signal corresponding to the detection result of the second laser light detection unit. The disc determination unit outputs a second laser light objective lens drive control signal for driving the second laser light objective lens, and based on the first laser light detection signal and the second laser light detection signal, the optical disc Determine the type. The drive difference adding unit generates a first laser light objective lens drive control signal for driving the first laser light objective lens by adding an offset value to the second laser light objective lens drive control signal.

Then, the first laser light objective lens driving unit drives the first laser light objective lens in accordance with the first laser light objective lens drive control signal. Then, the second laser light objective lens driving unit drives the second laser light objective lens in accordance with the second laser light objective lens drive control signal.
This optical disk apparatus has a configuration in which the first laser beam and the second laser beam are irradiated onto the optical disk independently, and the first laser beam and the second laser beam can be irradiated onto the optical disk at the same time. For this reason, the type of the disc loaded in the optical disc apparatus can be quickly determined. Further, in this optical disc apparatus, the first laser beam objective lens is driven by adding the offset value to the second laser beam objective lens drive control signal by the drive difference adder, so that the wavelength on the information surface of the optical disc Since the first long laser beam (low-energy laser beam) is irradiated first, the risk of destroying the information surface of the optical disk can be avoided.

  The fourth invention is the third invention, wherein the first laser light objective lens is the first of the first laser light objective lens and the optical disk in an initial state when performing an operation of discriminating the type of the disk. The first laser light objective lens is disposed at an initial position where the distance from the surface facing the laser light objective lens is longer than the focal length of the objective lens for the first laser light. . The first laser light objective lens driving unit drives the first laser light objective lens from the initial position for the first laser light objective lens in a direction in which the distance between the first laser light objective lens and the optical disk decreases. . The second laser light objective lens driving unit is configured to use the second laser light objective lens for the second laser light when the first laser light objective lens is located at the initial position for the first laser light objective lens. The first laser light objective lens drive unit moves the first laser light in the direction in which the distance between the second laser light objective lens and the optical disk decreases from the initial position for the second laser light objective lens, which is the position where the objective lens exists. Drive at the same speed as the optical objective lens is driven. The disc discriminating unit is configured so that the first laser light objective lens and the second laser light objective lens are initially used for the first laser light objective lens by the first laser light objective lens drive unit and the second laser light objective lens drive unit. The signal levels of the first laser light detection signal and the second laser light detection signal are set to a predetermined value during a period in which the position and the initial position for the second laser light objective lens are driven in the direction of decreasing the distance from the optical disk. By comparing with the threshold value, the type of the optical disk is determined.

According to a fifth aspect of the present invention, there is provided a first laser light source, a second laser light source, a third laser light source, a laser control unit, a laser beam mixing / separating unit, an optical path switching unit, a low NA objective lens, and a high NA objective. Lens, low NA objective lens drive unit, high NA objective lens drive unit, first laser light detection unit, second laser light detection unit, third laser light detection unit, servo signal generation unit, and disk An optical disc apparatus including a determination unit and a drive difference addition unit.
The first laser light source irradiates the first laser light. The second laser light source irradiates a second laser beam having a shorter wavelength than the first laser beam. The third laser light source irradiates a third laser beam having a shorter wavelength than the second laser beam. The laser control unit performs drive control of the first laser light source, the second laser light source, and the third laser light source. The laser beam mixing / separating unit mixes and separates the first laser beam and the second laser beam. The optical path switching unit sets the third laser beam as an optical path for guiding the third laser beam to the high NA objective lens in the ON state, and sets the optical path for guiding the third laser beam to the low NA objective lens in the OFF state. The low NA objective lens simultaneously irradiates the optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing / separating unit. When the optical path switching unit is in the ON state, the high NA objective lens irradiates the optical disk with the third laser light and has a higher aperture ratio than the low NA objective lens. The low NA objective lens drive unit varies the distance between the low NA objective lens and the optical disk by driving the low NA objective lens to and from the optical disk. The high NA objective lens drive unit varies the distance between the high NA objective lens and the optical disc by driving the high NA objective lens to the perspective of the optical disc. The first laser beam detector detects the intensity of the first laser beam reflected from the optical disk. The second laser beam detector detects the intensity of the second laser beam reflected from the optical disk. The third laser light detection unit detects the intensity of the third laser light reflected from the optical disk. The servo signal generation unit includes a first laser beam detection signal corresponding to the detection result of the first laser beam detection unit, a second laser beam detection signal corresponding to the detection result of the second laser beam detection unit, and a third laser A third laser light detection signal corresponding to the detection result in the light detection unit is generated. The disc determination unit outputs a high NA objective lens drive control signal for driving the high NA objective lens, and based on the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal, Determine the type of optical disc. The drive difference adding unit generates a low NA objective lens drive control signal for driving the low NA objective lens by adding an offset value to the high NA objective lens drive control signal.

The low NA objective lens driving unit drives the low NA objective lens by a low NA objective lens drive control signal. The high NA objective lens driving unit drives the high NA objective lens by a high NA objective lens drive control signal.
In this optical disc apparatus, when the optical path switching unit is in the ON state, the low NA objective lens simultaneously irradiates the optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing / separating unit, and at the same time, the high NA objective lens. Since the lens irradiates the optical disk with the third laser beam, various types of disk determination can be performed quickly. Furthermore, in this optical disc apparatus, when the optical path switching unit is in the OFF state, the low NA objective lens irradiates the optical disc with the third laser beam. Therefore, in this optical disc apparatus, the optical layer can be quickly and without destroying the information layer of the optical disc. It is possible to reliably discriminate many kinds of disks. Further, since the third laser with high power consumption can be reduced, the power consumed by the optical disk device can be suppressed.

  6th invention is 5th invention, Comprising: A low NA objective lens is a state which opposes the low NA objective lens and the low NA objective lens of an optical disk in the initial state in the case of performing the operation | movement which discriminate | determines the kind of disk. Is disposed at the initial position for the low NA objective lens, which is a position where the distance to the surface of the first laser light is longer than the focal length of the low NA objective lens. The low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance between the low NA objective lens and the optical disk is reduced from the initial position. The high NA objective lens driving unit moves the high NA objective lens from the initial position for the high NA objective lens where the high NA objective lens is located when the low NA objective lens is located at the initial position of the low NA objective lens. The low NA objective lens driving unit is driven at the same speed as that at which the low NA objective lens is driven in such a direction that the distance between the objective lens and the optical disk becomes smaller. Then, the disc discriminating unit is connected to the optical disc from the initial position for the low NA objective lens and the initial position for the high NA objective lens by the low NA objective lens driving unit and the high NA objective lens driving unit. By comparing the signal levels of the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal with a predetermined threshold value during the period in which the distance is reduced, Determine the type.

  The seventh invention is the fifth or sixth invention, wherein the drive control unit in the first stage receives the first laser light from the first laser light source, the second laser light from the second laser light source, Driving control is performed so that the third laser light is emitted from the three laser light sources, respectively, and in the second stage, driving control is performed so that only the third laser light is emitted from the third laser light source. The optical path switching unit is turned on in the first stage and turned off in the second stage, and the high NA objective lens driving unit is configured to move the high NA objective lens from the initial position for the high NA objective lens in the first stage. The high NA objective lens and the optical disk are driven in the direction of decreasing the distance, and the high NA objective lens is not driven in the second stage. In the first stage, the low NA objective lens driving unit is configured such that the high NA objective lens driving unit increases in the direction in which the distance between the low NA objective lens and the optical disk decreases from the initial position for the low NA objective lens. Driving is performed at the same speed as the driving speed of the NA objective lens, and in the second stage, the low NA objective lens is driven in a direction in which the distance between the low NA objective lens and the optical disk is reduced from the initial position for the low NA objective lens. The disc discriminating unit discriminates the type of the optical disc based on the first laser beam detection signal, the second laser beam detection signal, and the third laser beam detection signal in the first stage, and detects the third laser beam in the second stage. Based on the signal, the type of the optical disc is determined.

The eighth invention is the seventh invention, wherein the disk discriminating unit is configured such that, in the first stage, the low NA objective lens and the high NA objective lens are low NA by the low NA objective lens driving unit and the high NA objective lens driving unit. The first laser light detection signal, the second laser light detection signal, and the third laser light detection signal are driven in a direction in which the distance from the optical disk is reduced from the initial position for the objective lens and the initial position for the high NA objective lens. Is compared with a predetermined threshold value to determine the type of the optical disc. Then, in the second stage, the disc discriminating unit performs the third step in the period in which the low NA objective lens is driven by the low NA objective lens driving unit in a direction in which the distance from the initial position for the low NA objective lens is reduced. The type of the optical disc is determined by comparing the signal level of the laser light detection signal with a predetermined threshold value.
According to a ninth aspect of the invention, there is provided a first laser light source, a second laser light source, a third laser light source, a laser control unit, a laser light mixing / separating unit, an optical path switching unit, a low NA objective lens, and a high NA objective. A lens, a low NA objective lens drive unit, a high NA objective lens drive unit, a multiple laser beam detection unit, a third laser beam detection unit, a servo signal generation unit, a disk discrimination unit, a drive difference addition unit, , A disk device comprising:

  The first laser light source irradiates the first laser light. The second laser light source irradiates a second laser beam having a shorter wavelength than the first laser beam. The third laser light source irradiates a third laser beam having a shorter wavelength than the second laser beam. The laser control unit performs drive control of the first laser light source, the second laser light source, and the third laser light source. The laser beam mixing / separating unit mixes and separates the first laser beam and the second laser beam. The optical path switching unit sets the third laser beam as an optical path that guides the high-NA objective lens in the ON state, and sets the optical path that guides the third laser beam to the low-NA objective lens in the OFF state. The low NA objective lens simultaneously irradiates the optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing / separating unit. When the optical path switching unit is in the ON state, the high NA objective lens irradiates the optical disk with the third laser light and has a higher aperture ratio than the low NA objective lens. The low NA objective lens drive unit varies the distance between the low NA objective lens and the optical disk by driving the low NA objective lens to and from the optical disk. The high NA objective lens drive unit varies the distance between the high NA objective lens and the optical disc by driving the high NA objective lens to the perspective of the optical disc. The multiple laser beam detector detects the intensity of the first laser beam and the intensity of the second laser beam reflected from the optical disc. The third laser light detection unit detects the intensity of the third laser light reflected from the optical disk. The servo signal generation unit generates a multiple laser light detection signal corresponding to the detection result of the multiple laser light detection unit and a third laser light detection signal corresponding to the detection result of the third laser light detection unit. The disc discrimination unit outputs a low NA objective lens drive control signal for driving the low NA objective lens, and discriminates the type of the optical disc based on the multiple laser beam detection signal and the third laser beam detection signal. The drive difference adding unit generates a high NA objective lens drive control signal for driving the high NA objective lens by adding an offset value to the low NA objective lens drive control signal.

Then, the low NA objective lens driving unit drives the low NA objective lens by a low NA objective lens drive control signal. Further, the high NA objective lens driving unit drives the high NA objective lens by a high NA objective lens drive control signal.
In this optical disk apparatus, the same effect as that of the fifth invention can be obtained, and the intensity of the first laser light and the intensity of the second laser light reflected from the optical disk are detected by the multiple laser light detector. Therefore, it is not necessary to provide a plurality of laser light detection units.
As a result, the configuration of the optical disc apparatus can be simplified, and the cost can be reduced.
A tenth aspect of the invention is the ninth aspect of the invention, wherein the low NA objective lens is a side facing the low NA objective lens and the low NA objective lens of the optical disc in an initial state when performing an operation of discriminating the type of the disc. Is a position where the distance from the first disk surface, which is the surface of the first laser beam, is longer than the focal length of the low NA objective lens for the first laser light, and is a distance LEN0 from the first disk surface to the low NA objective lens side. It is arranged at the initial position for the low NA objective lens, which is a distant position. Then, in the initial state when performing the operation of discriminating the disc type, the high NA objective lens is (distance LEN0) − (offset value Offset) (Offset> 0) from the first disc surface.
It is arranged at the initial position for the high NA objective lens, which is a position that is far away.

Then, the low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance between the low NA objective lens and the optical disk becomes smaller from the initial position for the low NA objective lens. The high NA objective lens drive unit drives the high NA objective lens in the direction in which the distance between the high NA objective lens and the optical disc decreases from the initial position for the high NA objective lens, and the low NA objective lens drive unit drives the low NA objective lens. Drive at the same speed as The disc discriminating unit is configured such that the low NA objective lens driving unit and the high NA objective lens driving unit move the low NA objective lens and the high NA objective lens from the initial position for the low NA objective lens and the initial position for the high NA objective lens to the optical disc. The type of the optical disk is discriminated by comparing the signal levels of the multiplexed laser light detection signal and the third laser light detection signal with a predetermined threshold during the period of driving in the decreasing direction.
The eleventh aspect of the present invention is the tenth aspect of the present invention, wherein the high NA objective lens is LEN1 in the initial state, wherein the distance between the focal position of the low NA objective lens and the first disk surface for the first laser light is LEN1. When the distance between the focal position of the low NA objective lens and the first disk surface with respect to two laser beams is LEN2, and the distance between the focal position of the high NA objective lens with respect to the third laser beam and the first disk surface is LEN3. ,
LEN1>LEN2> LEN3
(Distance LEN0) − (Offset value Offset) (Offset> 0) from the first disk surface by the offset value Offset determined to be
It is arranged at the initial position for the high NA objective lens, which is a position that is far away.

  A twelfth aspect of the invention is any one of the ninth to eleventh aspects of the invention, wherein the drive control unit, in the first stage, outputs the first laser light from the first laser light source and the second laser light from the second laser light source. Are controlled so as to irradiate the third laser light from the third laser light source, respectively, and in the second stage, the drive control is performed so that only the third laser light is emitted from the third laser light source. The optical path switching unit is turned on in the first stage and turned off in the second stage. The low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance between the low NA objective lens and the optical disk decreases from the initial position for the low NA objective lens in the first stage. The NA objective lens is driven in a direction in which the distance between the low NA objective lens and the optical disc is reduced from the initial position for the low NA objective lens. In the first stage, the high NA objective lens drive unit is configured so that the low NA objective lens drive unit is low in the direction in which the distance between the high NA objective lens and the optical disk decreases from the initial position for the high NA objective lens. The NA objective lens is driven at the same speed as that for driving, and the high NA objective lens is not driven in the second stage. The disc discriminating unit discriminates the type of the optical disc based on the multiple laser beam detection signal and the third laser beam detection signal in the first step, and determines the type of the optical disc based on the third laser beam detection signal in the second step. Determine.

A thirteenth aspect of the invention is the twelfth aspect of the invention, wherein in the first stage, the disc determination unit causes the low NA objective lens and the high NA objective lens to be low NA by the low NA objective lens driving unit and the high NA objective lens driving unit. The signal levels of the multiplexed laser light detection signal and the third laser light detection signal are set to a predetermined threshold during a period in which the distance from the optical disk is decreased from the initial position for the objective lens and the initial position for the high NA objective lens. By comparing with the value, the type of the optical disc is discriminated. In the second stage, the low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance from the optical disc from the initial position for the low NA objective lens becomes smaller. In this period, the type of the optical disk is determined by comparing the signal level of the multiple laser light detection signal with a predetermined threshold value.
The fourteenth to seventeenth inventions are methods used in the optical disk apparatus, and have the same effects as the first, third, fifth, and ninth inventions.

The eighteenth to twenty-first inventions are programs used in the optical disc apparatus, and have the same effects as the first, third, fifth, and ninth inventions.
Twenty-second to twenty-fifth aspects of the present invention are integrated circuits used in the optical disc apparatus, and have the same effects as the first, third, fifth, and ninth aspects of the invention.

In the optical disk apparatus of the present invention, the function of switching the recording light emission drive signal used for recording laser emission to be used for reproduction laser emission inside the LDD and the resolution of the gain for amplifying the recording light emission drive signal are also equivalent to the reproduction light emission drive signal gain. Therefore, it is possible to emit a plurality of laser beams at the same time only by changing the circuit inside the LDD. Therefore, the thickness of the base material from the surface of the optical disk to the information surface is different and the corresponding laser wavelengths are different. In an optical disc apparatus that records or reproduces a type of disc, the time required for disc discrimination can be shortened.
Further, the same effect can be obtained even if the wavelength of the laser light irradiated from the same objective lens is freely selected.
Further, the same effect can be obtained even when three or more types of laser beams are irradiated from the same objective lens.

Further, by discriminating not the type of disc but the type of information surface on the disc, the substrate thickness from the surface of the optical disc to the information surface (the thickness of the substrate) is substantially the same, and the corresponding laser wavelengths are different. The same effect can be obtained even when discs having one information surface are discriminated.
Furthermore, the same effect can be obtained without increasing the number of front light monitors by reducing the laser output (laser light output level) to be irradiated to a low output (low output level).
Further, the same effect can be obtained even when high-frequency superimposition is applied to the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
Furthermore, even if the combination of the light emission drive signal and the laser light source that emits light is freely selected, the same effect can be obtained.

In addition, an objective lens that connects the focal positions of the red laser beam and the blue laser beam converged by the same objective lens to the far side in the normal direction (the optical axis direction of the objective lens) with respect to the objective lens. The thickness of the substrate from the surface of the optical disk to the information surface (the thickness of the substrate) In an optical disc apparatus that records or reproduces a plurality of types of discs including HD-DVDs and DVDs having substantially the same thickness (thickness), it is possible to avoid destruction of recorded information on the DVD information surface by HD-DVD blue laser light. it can.
Furthermore, an objective lens that connects the focal positions of the red laser beam and the blue laser beam converged by the same objective lens to the side closer to the normal direction (the optical axis direction of the objective lens) of the red laser beam with respect to the objective lens. The same effect can be obtained even if the position of the objective lens during the disc discrimination operation is moved away from the vicinity of the surface of the optical disc (the surface of the optical disc facing the objective lens).

Further, the same effect can be obtained even if the wavelength of the laser light irradiated from the same objective lens is freely selected.
Further, the same effect can be obtained even when three or more types of laser beams are irradiated from the same objective lens.
Further, by discriminating not the type of disc but the type of information surface on the disc, the substrate thickness from the surface of the optical disc to the information surface (the thickness of the substrate) is substantially the same, and the corresponding laser wavelengths are different. The same effect can be obtained even when discs having one information surface are discriminated.
Furthermore, the same effect can be obtained without increasing the number of front light monitors by reducing the laser output (laser light output level) to be irradiated to a low output (low output level).

In addition, an objective lens that focuses on the side closer to the normal direction (the optical axis direction of the objective lens) than the focal point of the blue laser light is used for the red laser beam, and the objective lens during disc discrimination operation is used. The same effect can be obtained by moving the position in the direction away from the vicinity of the surface of the optical disk (the surface of the optical disk facing the objective lens).
Further, the same effect can be obtained even when high-frequency superimposition is applied to the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
Furthermore, even if the combination of the light emission drive signal and the laser light source that emits light is freely selected, the same effect can be obtained.
Further, the focal positions of the red laser beam and the blue laser beam converged by the two objective lenses are connected to the far side in the normal direction (the optical axis direction of the objective lens) with respect to the objective lens. By providing a driving difference between the two objective lenses, destruction of recorded information on the DVD information surface by the blue laser beam of HD-DVD can be avoided more safely than in the case of the same objective lens configuration.

Further, the same effect can be obtained even if the wavelength of the laser light irradiated from the two objective lenses is freely selected.
Furthermore, the same effect can be obtained even when three or more types of laser beams are irradiated from two objective lenses.
Further, the focal positions of the red laser beam and the blue laser beam converged by separate objective lenses are connected to the side closer to the normal direction (the optical axis direction of the objective lens) with respect to the objective lens. The same effect can be obtained by providing a driving difference between the two objective lenses and moving the position of the objective lens during disc discrimination operation away from the vicinity of the surface of the optical disc (the surface of the optical disc facing the objective lens). can get.
Further, by discriminating not the type of disc but the type of information surface on the disc, the substrate thickness from the surface of the optical disc to the information surface (the thickness of the substrate) is substantially the same, and the corresponding laser wavelengths are different. The same effect can be obtained even when discs having one information surface are discriminated.

Furthermore, the same effect can be obtained without increasing the number of front light monitors by reducing the laser output (laser light output level) to be irradiated to a low output (low output level).
Further, the same effect can be obtained even when high-frequency superimposition is applied to the recording light emission driving signal during reproduction light emission using the recording light emission driving signal.
Furthermore, even if the combination of the light emission drive signal and the laser light source that emits light is freely selected, the same effect can be obtained.
Also, a low NA objective lens in which the focal point of the infrared laser beam is focused in the direction normal to the objective lens (the optical axis direction of the objective lens) from the focal point of the red laser beam is used. The disc thickness of the base material (the thickness of the base material) from the surface of the optical disc to the information surface is substantially the same by performing the disc discriminating process of the ray disc, DVD and CD, and thereafter discriminating the HD-DVD. In an optical disc apparatus that records or reproduces a plurality of types of discs including DVDs and DVDs, it is possible to reliably avoid destruction of recorded information on the DVD information surface by blue laser light of HD-DVD.

In addition, a low-NA objective lens that focuses on the side closer to the normal direction (the optical axis direction of the objective lens) than the focal point of the red laser light is used to discriminate the disc. The same effect can be obtained by moving the position of the low NA objective lens during operation away from the vicinity of the surface of the optical disc (the surface of the optical disc facing the objective lens).
Further, the same effect can be obtained even if the LDD has a configuration in which the combination of the light emission drive signal used for laser light emission and the laser light source can be freely selected.
Furthermore, the same applies when discriminating a disc having a plurality of information planes with different recording densities and corresponding laser wavelengths by discriminating not the disc type but the type of information surface on the disc. The effect is obtained.
Furthermore, the same effect can be obtained without increasing the number of front light monitors by reducing the laser output (laser output level) to be irradiated to a low output (low output level).

  Further, the same effect can be obtained even when high-frequency superposition is performed on the recording light emission drive signal during reproduction light emission using the recording light emission driving signal.

Hereinafter, embodiments of the present invention will be described.
[First Embodiment]
<1.1: Configuration of optical disc apparatus>
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing a configuration of an optical disc apparatus 100 according to the present embodiment.
The optical disc apparatus 100 includes an infrared laser light source 11, an infrared laser light beam splitter 13, an infrared laser light front light monitor 15, a red laser light source 12, a red laser light beam splitter 14, and a red laser light front light monitor. 16, irradiation beam splitter 20, objective lens 29, focus actuator 34, detector beam splitter 21, infrared laser beam detector 23, red laser beam detector 24, servo signal generation circuit (servo signal generation unit) 56, light emission A laser selection SW 41 and a reproduction light emission drive signal gain amplifier 42 are provided.

Further, the optical disc apparatus 100 includes a laser controller (laser control unit) 54, a disc discrimination controller (disc discrimination unit) 51, a recording light emission drive signal switching SW 43, a simultaneous light emission gain amplifier 44, and a recording light emission drive signal gain amplifier 45. .
In FIG. 1, an optical disk 1, an infrared laser light source 11, an infrared laser light beam splitter 13, an infrared laser light front light monitor 15, a red laser light source 12, a red laser light beam splitter 14, and a red laser light front. Optical monitor 16, irradiation beam splitter 20, objective lens 29, focus actuator 34, detector beam splitter 21, infrared laser light detector 23, red laser light detector 24, servo signal generation circuit (servo signal generation unit) 56 The light emission laser selection SW 41 and the reproduction light emission drive signal gain amplifier 42 have functions equivalent to those of the optical disc apparatus 900 of the background art, and detailed description thereof is omitted.

The difference from the background art is that a laser controller (laser control unit) 54, a disc discrimination controller (disc discrimination unit) 51, a recording light emission drive signal switching SW 43, a simultaneous light emission gain amplifier 44, and a recording light emission drive signal gain amplifier 45 are used. As a result, the optical disk 1 loaded in the optical disk apparatus 100 can be divided into a plurality of disk types by a single objective lens operation (operation to move the objective lens 29 closer to or away from the optical disk 1) while simultaneously emitting laser beams of a plurality of wavelengths. It is a place where it is possible to determine which type of disk is in a short time.
The infrared laser light source 11 of FIG. 1 irradiates infrared laser light having a wavelength of about 780 [nm]. The infrared laser beam splitter 13 splits the infrared laser beam into the irradiation beam splitter 20 and the infrared laser beam front light monitor 15. The infrared laser beam front light monitor 15 detects the output power of the irradiated infrared laser beam. Then, the output of the infrared laser beam front light monitor 15 is input to the laser control unit 54.

The red laser light source 12 emits red laser light having a wavelength of about 650 [nm]. The red laser beam splitter 14 splits the red laser beam into the irradiation beam splitter 20 and the red laser beam front light monitor 16. The red laser light front light monitor 16 detects the output power of the irradiated red laser light. The output of the red laser light front light monitor 16 is input to the laser control unit 54.
The red laser beam and the infrared laser beam that have been split by the irradiation beam splitter 20 are reflected by the irradiation beam splitter 20 in the direction of the objective lens 29 and converged on the information surface of the optical disc 1 by the objective lens 29. The red laser light and the infrared laser light reflected by the optical disk 1 pass through the irradiation beam splitter 20, and the red laser light passes through the detector beam splitter 21 and is irradiated on the red laser light detector 24, and the infrared laser light. The laser light is irradiated to the infrared laser light detector 23 by the detector beam splitter 21. The output of the red laser light detector 24 and the output of the infrared laser light detector 23 are input to the servo signal generation unit 56.

The laser controller (laser control unit) 54 uses the red laser output (red laser light output power level) detected by the red laser light front light monitor 16 and the infrared laser light front light monitor 15 during reproduction. A reproduction light emission drive signal is output to the LDD 40 such that the detected infrared laser output (the level of the output power of the infrared laser beam) becomes a predetermined reproduction laser output level. The laser controller (laser controller) 54 also detects the red laser output (red laser light output power level) detected by the red laser light front light monitor 16 and the infrared laser light front light monitor during recording. The reproduction light emission drive signal and the recording light emission drive signal are output to the LDD 40 so that the infrared laser output (the level of the output power of the infrared laser light) detected at 15 becomes a predetermined recording laser output level.
The LDD 40 mainly includes a light emission laser selection SW 41, a reproduction light emission drive signal gain amplifier 42, a recording light emission drive signal switching SW 43, a simultaneous light emission gain amplifier 44, a recording light emission drive signal gain amplifier 45, and a first adder. 401 and a second adder 402.

The recording light emission drive signal gain amplifier 45 amplifies the recording light emission drive signal. Specifically, the recording light emission drive signal gain amplifier 45 amplifies the recording light emission drive signal output from the recording light emission drive signal switching SW 43 with a predetermined gain, and outputs the amplified signal to the first adder 401. The recording light emission drive signal gain amplifier 45 has a lower resolution and a higher amplification factor than the reproduction light emission drive signal gain amplifier 42.
During reproduction, the LDD 40 amplifies the reproduction light emission drive signal by a signal for laser drive obtained by multiplying the reproduction light emission drive signal by the reproduction light emission drive signal gain amplifier 42 (a gain (amplification factor) of the reproduction light emission drive signal gain amplifier 42). The signal obtained by doing so is output to the infrared laser light source 11 or the red laser light source 12. In recording, the LDD 40 is a laser driving signal obtained by multiplying the reproduction light emission driving signal by the reproduction light emission driving signal gain amplifier 42 and a laser driving signal obtained by multiplying the recording light emission driving signal by the recording light emission driving signal gain amplifier 45. A signal for laser driving obtained by adding (a signal obtained by amplifying the recording light emission driving signal by the gain (amplification factor) of the recording light emission driving signal gain amplifier 45) is an infrared laser light source 11 or a red laser light source 12. Output to.

  The recording light emission drive signal switching SW 43 of the LDD 40 is normally set to connect the recording light emission drive signal to the recording light emission drive signal gain amplifier 45. The recording light emission drive signal switching SW 43 receives an output from the laser control unit 54 as an input, and is input based on a control signal from the disc discrimination unit 51 (a signal indicating whether or not the disc type discrimination operation is being performed). Is a changeover switch that outputs to the recording light emission drive signal gain amplifier 45 or the simultaneous light emission gain amplifier 44. Specifically, the recording / light emission drive signal switching SW 43 performs an operation (hereinafter referred to as “disc discriminating operation”) for discriminating what type of disc the optical disc 1 loaded in the optical disc apparatus 100 is. The input is output to the simultaneous light emission gain amplifier 44 only during the current period, and the input is output to the recording light emission drive signal gain amplifier 45 during the other periods.

A disc discriminating controller (disc discriminating unit) 51 is a laser driving signal amplified by the LDD 40 multiplying the reproduction light emission drive signal by the reproduction light emission drive signal gain amplifier 42 (reproduction light emission drive signal gain reproduction light emission drive signal gain amplifier). The LDD 40 switches the emission laser selection SW 41 so that the laser drive signal obtained by multiplying the gain of 42 is output to the red laser light source 12, and the LDD 40 sets the simultaneous emission gain amplifier 44 to the recording emission drive signal. The LDD 40 records so as to output the multiplied laser drive signal (the laser drive signal obtained by multiplying the recording light emission drive signal by the gain of the simultaneous light emission gain amplifier 44) to the infrared laser light source 11. The light emission drive signal switch SW43 is switched.
When performing the disc discrimination operation, the disc discrimination controller (disc discrimination unit) 51 sets the light emission laser selection SW 41 so that the LDD 40 outputs the reproduction light emission drive signal amplified by the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The recording light emission drive signal switching SW 43 is switched so that the LDD 40 outputs the recording light emission drive signal amplified by the simultaneous light emission gain amplifier 44 to the infrared laser light source 11. (The recording light emission drive signal switching SW 43 is switched to the b side). As a result, the optical disc apparatus 100 can emit red laser light and infrared laser light simultaneously to irradiate the optical disc 1.

Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal for controlling the output of the red laser light source 12 and the output of the infrared laser light source 11 to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40, and a recording light emission drive signal is output to the LDD 40 so that the output of the infrared laser light source 11 becomes a predetermined reproduction laser output level, thereby simultaneously irradiating the red laser beam and the infrared laser beam.
The disc discrimination controller (disc discriminator) 51 outputs a drive signal for driving the objective lens 29 up and down (far and near) to the focus actuator 34.

The servo signal generation circuit (servo signal generation unit) 56 generates a servo signal from the outputs from the red laser light detector 24 and the infrared laser light detector 23 and outputs the servo signal to the disc determination unit 51. The disc discrimination controller (disc discriminating unit) 51 discriminates the type of the loaded disc based on the servo signal generated by the servo signal generation circuit (servo signal generation unit) 56.
The first adder 401 adds the output of the reproduction light emission drive signal gain amplifier 42 and the output of the recording light emission drive signal gain amplifier 45 and outputs the result to the light emission laser selection SW 41. In FIG. 1, for convenience of explanation, the mere adder is illustrated. However, the first adder 401 determines whether or not to perform addition processing for two inputs in accordance with the write strategy of the optical disc apparatus 100. Thus, the output of the first adder can be output as, for example, a multi-pulse signal, a recording power signal, a reproducing power signal, an erasing power signal, or the like.

The second adder 402 adds the output from the d side of the light emission laser selection SW 41 and the output from the simultaneous light emission gain amplifier 44 and outputs the result to the infrared laser light source 11.
The recording light emission drive signal switching SW 43 receives the output from the laser control unit 54 and switches the output destination to the recording light emission drive signal gain amplifier 45 or the simultaneous light emission gain amplifier 44 based on the control signal from the disc determination unit 51. (Selector). The recording light emission drive signal switching SW 43 selects the b side during the disc discrimination operation and selects the a side during the other periods.
The light emission laser selection SW 41 is a switch (selector) that takes the output of the first adder as an input and switches the output destination to the red laser light source 12 or the infrared laser light source 11 based on a control signal from the disc determination unit 51. In principle, the light emission laser selection SW 41 selects the c side when emitting red laser light, and the d side when emitting infrared laser light. However, during the disc discrimination operation period, the c side is selected as described above.

In the LDD 40, the recording light emission drive signal gain amplifier 45 amplifies the drive signal by using the simultaneous light emission gain amplifier 44 for the recording / reproduction drive signal because the amplification factor is too high for the reproduction laser light emission and the resolution is rough. To do. That is, the infrared laser light source 11 is driven using the recording / reproducing drive signal amplified by the simultaneous emission gain amplifier 44 having an amplification factor suitable for reproducing laser light.
<1.2: Operation of Optical Disc Device>
(1.2.1: Disc discrimination operation (for CD))
Next, with reference to FIG. 2 and FIG. 3, an operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 100 is a CD will be described in detail.

FIG. 2A shows a CD having an information surface at a position of about 1.2 mm from the surface of the optical disc 1 (the surface of the optical disc 1 facing the objective lens 29), infrared laser light and red laser light simultaneously. It is a schematic diagram which shows the emitted and converged laser beam.
FIG. 3 shows the objective lens position and the focus error signal when the objective lens 29 is driven in the state where the infrared laser beam and the red laser beam are simultaneously emitted from the CD in the optical disc apparatus 100.
FIG. 3 (1) is a diagram showing the relationship between time and the position of the objective lens 29, where the horizontal axis is time and the vertical axis is the position of the objective lens 29. Specifically, FIG. 3 (1) shows a position signal of the objective lens 29 when the red laser light and the infrared laser light are simultaneously emitted to bring the objective lens 29 close to the CD.

FIG. 3B is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 3B shows that the servo signal generation circuit (servo signal generation unit) 56 is red when the objective lens 29 is brought close to the CD by simultaneously emitting red laser light and infrared laser light. A focus error signal (corresponding to a signal transmitted by the signal line P1 in FIG. 1) generated from the output of the outside laser light detector 23 is shown.
FIG. 3 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 3 (3) shows that the servo signal generation circuit (servo signal generation unit) 56 is red when the objective lens 29 is brought close to the CD by simultaneously emitting red laser light and infrared laser light. A focus error signal (corresponding to a signal transmitted through the signal line P2 in FIG. 1) generated from the output of the laser beam detector 24 is shown.

  At the disc discrimination start timing T1, the disc discrimination controller (disc discriminator) 51 starts the disc discrimination operation. The disc discriminating controller (disc discriminating unit) 51 outputs a signal for laser driving amplified by the LDD 40 by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The LDD 40 switches the emission laser selection SW 41 (switches to the c side of the emission laser selection SW 41), and the LDD 40 multiplies the recording emission drive signal by the gain of the simultaneous emission gain amplifier 44 and outputs a red signal for laser driving. The recording light emission drive signal switch SW43 of the LDD 40 is switched so as to output to the outer laser light source 11 (switched to the b side of the recording light emission drive signal switch SW43). Here, since the b side of the recording light emission drive signal switching SW 43 is selected, nothing is output from the recording light emission drive signal gain amplifier 45. Therefore, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW41.

  Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 40), and the recording light emission drive signal such that the output of the infrared laser light source 11 becomes a predetermined reproduction laser output level is output to the LDD 40 (specific example). Specifically, the laser light is output to the simultaneous light emission gain amplifier 44) via the recording light emission drive signal switching SW 43 of the LDD 40, so that the red laser light and the infrared laser light are simultaneously irradiated. Further, the disc discrimination controller (disc discriminator) 51 raises the position of the objective lens 29 by giving a drive signal to the focus actuator 34 (moves the objective lens 29 in the direction in which the distance from the optical disc 1 is reduced).

As shown in FIG. 2, the objective lens 29 has an optical characteristic that the focal length of the infrared laser light is longer than the focal length of the red laser light.
At timing T2, the focus of the infrared laser light passes through the surface of the CD (the surface of the optical disc 1 on the side facing the objective lens 29), and the focus error signal is based on the signal from the infrared laser light detector 23 when passing. Is obtained. That is, a focus error signal having a waveform as indicated by W301 in FIG. 3 is output in the vicinity of timing T2.
As shown in FIG. 2 (a), the focal point of the infrared laser beam is focused on the far side in the normal direction (the optical axis direction of the objective lens 29) with respect to the objective lens 29 than the focal point of the red laser beam. Since the lens 29 is used, at the timing T3, the focal point of the red laser light passes through the surface of the CD (the surface of the optical disc 1 on the side facing the objective lens 29), and from the red laser light detector 24 at the time of passage. A focus error signal is obtained based on the signal. That is, a focus error signal having a waveform as indicated by W303 in FIG. 3 is output in the vicinity of timing T3.

At timing T4, the focal point of the infrared laser beam passes through the information surface (the surface on which information is recorded) of the CD, and a focus error signal is obtained based on the signal from the infrared laser beam detector 23 when passing. That is, a focus error signal level having a waveform as indicated by W302 in FIG. 3 is output in the vicinity of timing T4. When the amplitude of the focus error signal obtained at this time exceeds a certain level L1, the disc discrimination controller (disc discriminator) 51 determines that the loaded disc is a CD.
If it is determined that the disk loaded in the optical disk device 100 is a CD, the disk determination controller (disk determination unit) 51 ends the disk determination operation.
(1.2.2: Disc discrimination operation (for DVD))
Next, with reference to FIG. 2 and FIG. 4, the operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 100 is a DVD will be described in detail.

FIG. 2B shows a DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 facing the objective lens 29), infrared laser light and red laser light simultaneously. It is a schematic diagram which shows the emitted and converged laser beam.
FIG. 4 shows an objective lens position and a focus error signal when the objective lens 29 is driven in a state where infrared laser light and red laser light are simultaneously emitted from a DVD.
FIG. 4 (1) is a diagram showing the relationship between time and the position of the objective lens 29 with the horizontal axis representing time and the vertical axis representing the position of the objective lens 29. Specifically, FIG. 4 (1) shows a position signal of the objective lens 29 when the red laser light and the infrared laser light are simultaneously emitted to bring the objective lens 29 close to the DVD.
FIG. 4B is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 4B shows that the servo signal generation circuit (servo signal generation unit) 56 is red when the objective lens 29 is brought close to the DVD by simultaneously emitting red laser light and infrared laser light. A focus error signal (corresponding to a signal transmitted by the signal line P1 in FIG. 1) generated from the output of the outside laser light detector 23 is shown.

FIG. 4 (3) is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 4C shows that the servo signal generation circuit (servo signal generation unit) 56 is red when the objective lens 29 is brought close to the DVD by simultaneously emitting red laser light and infrared laser light. A focus error signal (corresponding to a signal transmitted through the signal line P2 in FIG. 1) generated from the output of the laser beam detector 24 is shown.
At the disc discrimination start timing T5, the disc discrimination controller (disc discriminator) 51 starts the disc discrimination operation. The disc discriminating controller (disc discriminating unit) 51 outputs an LDD 40 to the red laser light source 12 so that the LDD 40 multiplies and amplifies the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42. The laser light selection SW41 is switched (switched to the c side of the light emission laser selection SW41), and the LDD 40 multiplies the recording light emission drive signal by the gain of the simultaneous light emission gain amplifier 44, and the signal for laser drive amplified is infrared. The recording light emission drive signal switch SW43 of the LDD 40 is switched so as to output to the laser light source 11 (switched to the b side of the recording light emission drive signal switch SW43). Here, since the b side of the recording light emission drive signal switching SW 43 is selected, nothing is output from the recording light emission drive signal gain amplifier 45. Therefore, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW41.

  Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 40), and the recording light emission drive signal such that the output of the infrared laser light source 11 becomes a predetermined reproduction laser output level is output to the LDD 40 (specific example). Specifically, the laser light is output to the simultaneous light emission gain amplifier 44) via the recording light emission drive signal switching SW 43 of the LDD 40, so that the red laser light and the infrared laser light are simultaneously irradiated. Further, the disc discrimination controller (disc discriminator) 51 raises the position of the objective lens 29 by giving a drive signal to the focus actuator 34 (moves the objective lens 29 in the direction in which the distance from the optical disc 1 is reduced).

At timing T6, the focus of the infrared laser passes through the surface of the DVD (the surface of the optical disc 1 on the side facing the objective lens 29), and a focus error signal is generated based on the signal from the detector 23 for infrared laser light. can get. That is, a focus error signal having a waveform as indicated by W401 in FIG. 4 is output in the vicinity of timing T6.
As shown in FIG. 2B, an objective lens 29 is used in which the infrared laser focus is focused on the far side in the normal direction (the optical axis direction of the objective lens 29) with respect to the objective lens 29 from the red laser focus. Therefore, at the timing T7, the focal point of the red laser light passes through the surface of the DVD, and a focus error signal is obtained based on the signal from the red laser light detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W403 in FIG. 4 is output in the vicinity of timing T7.

At timing T8, the focal point of the infrared laser beam passes through the information surface of the DVD, and a focus error signal is obtained based on the signal from the infrared laser beam detector 23 at the time of passage. That is, a focus error signal having a waveform as indicated by W402 in FIG. 4 is output in the vicinity of timing T8. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L1, the disc discrimination controller (disc discriminator) 51 continues the disc discrimination operation.
At timing T9, the focal point of the red laser light passes through the information surface of the DVD, and a focus error signal is obtained based on the signal from the red laser light detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W404 in FIG. 4 is output in the vicinity of timing T9. When the amplitude of the focus error signal obtained at this time exceeds a certain level L2, the disc discrimination controller (disc discriminator) 51 determines that the disc loaded in the optical disc apparatus 100 is a DVD.

If it is determined that the loaded disk is a DVD, the disk determination controller (disk determination unit) 51 ends the disk determination operation.
As described above, a plurality of types of discs are recorded in which the thickness of the base material from the surface of the optical disc 1 (the surface of the optical disc 1 facing the objective lens 29) to the information surface is different and the corresponding laser wavelengths are different. Alternatively, in the optical disk device to be reproduced, the plurality of types of disks are discriminated by a single objective lens operation while simultaneously emitting a plurality of types of lasers having different wavelengths, so that the time required for disc type discrimination can be shortened.
Further, by using a recording light emission driving signal used for recording laser light emission for reproduction, simultaneous light emission can be realized only by changing the configuration inside the LDD. Therefore, in the optical disc apparatus 100, the optical disc apparatus 100 of the present invention can be realized without changing circuits other than the LDD.

In addition, as long as two types of lasers having different wavelengths are used, laser light having any wavelength is not limited to red laser light and infrared laser light.
Further, three or more types of lasers having different wavelengths may be used.
In the present embodiment, an example of discriminating the type of the disc loaded in the optical disc apparatus 100 has been shown. However, when one disc has a plurality of information surfaces with different recording densities and corresponding laser wavelengths, You may make it discriminate | determine whether it is a disc with the kind of information surface.
In this embodiment, the front light monitor is provided for each laser wavelength. However, the front light monitor may be provided to irradiate the laser at a low output.
In addition, when laser light emission is performed with a recording light emission drive signal at the time of disc discrimination operation, a high frequency may be superimposed on the recording light emission drive signal.

In the present embodiment, the laser light source to be controlled by the reproduction light emission drive signal and the recording light emission drive signal at the time of disc determination operation is fixed, but may be freely selected.
[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS.
<2.1: Configuration of optical disc apparatus>
FIG. 5 is a block diagram showing a configuration of the optical disc apparatus 200 according to the present embodiment.
The optical disc apparatus 200 includes a red laser light source 12, a red laser beam splitter 14, a red laser beam front light monitor 16, an irradiation beam splitter 20, an objective lens 29, a focus actuator 34, a detector beam splitter 21, and a red laser beam. Detector 24, servo signal generation circuit (servo signal generation unit) 56, light emission laser selection SW 41, reproduction light emission drive signal gain laser controller (laser control unit) 54, disk discrimination controller (disk discrimination unit) 51, recording light emission drive signal switching SW 43, simultaneous light emission gain amplifier 44, and recording light emission drive signal gain amplifier 45 are provided.

Further, the optical disc apparatus 200 includes a blue laser light source 17, a blue laser light beam splitter 18, a blue laser light front light monitor 19, and a blue laser light detector 25.
In FIG. 5, an optical disk 1, a red laser light source 12, a red laser light beam splitter 14, a red laser light front light monitor 16, an irradiation beam splitter 20, an objective lens 29, a focus actuator 34, a detector beam splitter 21, and a red color. Laser light detector 24, servo signal generation circuit (servo signal generation unit) 56, light emission laser selection SW41, reproduction light emission drive signal gain laser controller (laser control unit) 54, disk discrimination controller (disk discrimination unit) 51, recording light emission drive The signal switching SW 43, the simultaneous light emission gain amplifier 44, and the recording light emission drive signal gain amplifier 45 have functions equivalent to those of the background art and the optical disk device of the first embodiment, and detailed description thereof is omitted.

In this embodiment, the background art and the first embodiment are different from each other by using a blue laser light source 17, a blue laser light beam splitter 18, a blue laser light front light monitor 19, and a blue laser light detector. The optical disc 1 loaded in the optical disc apparatus 100 is a plurality of disc types by one objective lens operation (operation to bring the objective lens 29 close to or away from the optical disc 1) while simultaneously emitting laser beams of a plurality of wavelengths. The type of disc can be determined in a short time and destruction of recorded information on the information surface can be avoided.
The blue laser light source 17 emits blue laser light having a wavelength of about 405 [nm]. The blue laser beam splitter 18 splits the blue laser beam into the irradiation beam splitter 20 and the blue laser beam front light monitor 19. The blue laser light front light monitor 19 detects the output power of the emitted blue laser light. The output of the blue laser light front light monitor 19 is input to the laser controller 54.

The red laser light source 12 emits red laser light having a wavelength of about 650 [nm]. The red laser beam splitter 14 splits the red laser beam into the irradiation beam splitter 20 and the red laser beam front light monitor 16. The red laser light front light monitor 16 detects the output power of the irradiated red laser light. The output of the red laser light front light monitor 16 is input to the laser control unit 54.
The red laser light and the blue laser light that have been split by the irradiation beam splitter 20 are reflected by the irradiation beam splitter 20 in the direction of the objective lens 29 and are converged on the information surface of the optical disc 1 by the objective lens 29. The red laser light and the blue laser light reflected by the optical disc 1 pass through the irradiation beam splitter 20, and the red laser light passes through the detector beam splitter 21 and is irradiated to the red laser light detector 24, and the blue laser light. Is irradiated to the detector 25 for blue laser light by the beam splitter 21 for detectors. The positional relationship between the red laser light detector 24 and the blue laser light detector 25 is determined by the optical characteristics of the detector beam splitter 21. Therefore, it goes without saying that the positional relationship between the red laser light detector 24 and the blue laser light detector 25 can be reversed from the positional relationship shown in FIG. 5 due to the optical characteristics of the detector beam splitter 21. .

The laser controller (laser controller) 54 detects the red laser output (red laser light output power level) detected by the red laser light front light monitor 16 and the blue laser light front light monitor 19 during reproduction. A reproduction light emission driving signal is output to the LDD 40 so that the blue laser output (the level of the output power of the blue laser light) is a predetermined reproduction laser output level. The laser controller (laser controller) 54 also records the red laser output (red laser light output power level) detected by the red laser light front light monitor 16 and the blue laser light front light monitor 19 during recording. The reproduction light emission drive signal and the recording light emission drive signal are output to the LDD 40 so that the blue laser output (the level of the output power of the blue laser light) detected in step 1 becomes a predetermined recording laser output level.
At the time of reproduction, the LDD 40 outputs, to the blue laser light source 17 or the red laser light source 12, a laser driving signal obtained by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42. At the time of recording, the LDD 40 performs laser driving by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 and the laser emission signal by multiplying the recording light emission drive signal by the gain of the recording light emission drive signal gain amplifier 45. A signal for driving the laser to which the signal for adding is output to the blue laser light source 17 or the red laser light source 12.

The recording light emission drive signal switching SW 43 of the LDD 40 is normally set to connect the recording light emission drive signal to the recording light emission drive signal gain amplifier 45. The recording light emission drive signal switching SW 43 receives the output from the laser control unit 54 and inputs an input based on a control signal from the disc discrimination unit 51 (a signal indicating whether or not the disc discrimination operation is being performed). This is a changeover switch that outputs to the recording light emission drive signal gain amplifier 45 or the simultaneous light emission gain amplifier 44. Specifically, the recording light emission drive signal switching SW 43 outputs the input to the simultaneous light emission gain amplifier 44 only during the period in which the disc discrimination operation is being executed, and the input is used for the recording light emission drive signal gain during the other periods. The amplifier 45 is made to output.
The disc discriminating controller (disc discriminating unit) 51 emits the laser of the LDD 40 so that the LDD 40 outputs to the red laser light source 12 a laser driving signal obtained by multiplying the reproduction light emission driving signal by the gain of the reproduction light emission driving signal gain amplifier 42. The selection SW 41 is switched, and the LDD 40 switches the recording light emission drive signal switching SW 43 of the LDD 40 so as to output a laser driving signal obtained by multiplying the recording light emission driving signal by the gain of the simultaneous light emission gain amplifier 44 to the blue laser light source 17.

When performing the disc discrimination operation, the disc discrimination controller (disc discrimination unit) 51 sets the light emission laser selection SW 41 so that the LDD 40 outputs the reproduction light emission drive signal amplified by the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The recording light emission drive signal switching SW 43 is switched so that the LDD 40 outputs the recording light emission drive signal amplified by the simultaneous light emission gain amplifier 44 to the blue laser light source 17 (switching the light emission laser selection SW 41 to the c side) ( The recording light emission drive signal switch SW43 is switched to the b side). As a result, the optical disc apparatus 200 can emit the red laser beam and the blue laser beam at the same time to irradiate the optical disc 1.
Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal for controlling the output of the red laser light source 12 and the output of the blue laser light source 17 to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40, and a recording light emission drive signal is output to the LDD 40 so that the output of the blue laser light source 17 becomes a predetermined reproduction laser output level, thereby simultaneously irradiating the red laser light and the blue laser light.

The disc discrimination controller (disc discriminator) 51 outputs a drive signal for driving the objective lens 29 up and down (far and near) to the focus actuator 34.
The servo signal generation circuit (servo signal generation unit) 56 generates a servo signal from the outputs from the red laser light detector 24 and the blue laser light detector 25 and outputs the servo signal to the disc determination unit 51. The disc discrimination controller (disc discriminating unit) 51 discriminates the type of the loaded disc based on the servo signal generated by the servo signal generation circuit (servo signal generation unit) 56.
In the LDD 40, the recording light emission drive signal gain amplifier 45 amplifies the drive signal by using the simultaneous light emission gain amplifier 44 for the recording / reproduction drive signal because the amplification factor is too high for the reproduction laser light emission and the resolution is rough. To do. That is, the blue laser light source 17 is driven using the recording / reproducing drive signal amplified by the simultaneous emission gain amplifier 44 having an amplification factor suitable for reproducing laser light emission.

The first adder 401, the second adder 402, the recording light emission drive signal switching SW 43, and the light emission laser selection SW 41 are the same as those described in the first embodiment, and thus detailed description thereof is omitted.
<2.2: Operation of Optical Disc Device>
(2.2.1: Disc discriminating operation (in the case of DVD))
Next, with reference to FIG. 6 and FIG. 7, the operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 200 is a DVD will be described in detail.
FIG. 6B shows a DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 facing the objective lens 29), and a blue laser beam and a red laser beam simultaneously. It is a schematic diagram which shows the converged laser beam.

FIG. 7 shows an objective lens position and a focus error signal when the objective lens 29 is driven in a state in which blue laser light and red laser light are simultaneously emitted from the DVD in the optical disc apparatus 200.
FIG. 7A is a diagram showing the relationship between time and the position of the objective lens 29 with the horizontal axis representing time and the vertical axis representing the position of the objective lens 29. Specifically, FIG. 7A shows a position signal of the objective lens 29 when the red laser light and the blue laser light are simultaneously emitted to bring the objective lens 29 close to the DVD.
FIG. 7B is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 7B shows that the servo signal generation circuit (servo signal generation unit) 56 when the objective lens 29 is brought close to the DVD by simultaneously emitting the red laser beam and the blue laser beam is the red laser. A focus error signal (corresponding to a signal transmitted through the signal line P1 in FIG. 5) generated from the output of the light detector 24 is shown.

FIG. 7 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 7 (3) shows that the servo signal generation circuit (servo signal generation section) 56 when the objective lens 29 is brought close to the DVD by simultaneously emitting red laser light and blue laser light is a blue laser. A focus error signal (corresponding to a signal transmitted through the signal line P2 in FIG. 5) generated from the output of the light detector 25 is shown.
At the disc discrimination start timing T10, the disc discrimination controller (disc discriminator) 51 starts the disc discrimination operation. The disc discriminating controller (disc discriminating unit) 51 outputs a signal for laser driving amplified by the LDD 40 by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The LDD 40 switches the emission laser selection SW 41 (switches to the c side of the emission laser selection SW 41), and the LDD 40 multiplies the recording emission driving signal by the gain of the simultaneous emission gain amplifier 44 so that the laser driving signal amplified is blue. The recording light emission drive signal switch SW43 of the LDD 40 is switched so as to output to the laser light source 17 (switched to the b side of the recording light emission drive signal switch SW43). Here, since the b side of the recording light emission drive signal switching SW 43 is selected, nothing is output from the recording light emission drive signal gain amplifier 45. Therefore, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW41.

  Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 40), and the recording light emission drive signal such that the output of the blue laser light source 17 becomes a predetermined reproduction laser output level is output to the LDD 40 (specific In this case, the laser light is output to the simultaneous light emission gain amplifier 44) via the recording light emission drive signal switching SW 43 of the LDD 40, so that the red laser light and the blue laser light are simultaneously irradiated. Further, the disc discrimination controller (disc discriminator) 51 raises the position of the objective lens 29 by giving a drive signal to the focus actuator 34 (moves the objective lens 29 in the direction in which the distance from the optical disc 1 is reduced).

As shown in FIG. 6, the objective lens 29 has an optical characteristic that the focal length of the red laser light is longer than the focal length of the blue laser light.
At timing T11, the focus of the red laser light passes through the surface of the DVD (the surface of the optical disc 1 on the side facing the objective lens 29), and a focus error signal is obtained based on the signal from the detector 24 for red laser light when passing. It is done. That is, a focus error signal having a waveform as indicated by W701 in FIG. 7 is output in the vicinity of timing T11.
As shown in FIG. 6B, the objective lens 29 in which the focal point of the red laser beam is focused on the far side in the normal direction (the optical axis direction of the objective lens 29) with respect to the objective lens 29 from the focal point of the blue laser beam. Therefore, at the timing T12, the focal point of the blue laser light passes through the surface of the DVD (the surface of the optical disc 1 on the side facing the objective lens 29), and the signal from the detector 25 for blue laser light passes through when passing. Based on this, a focus error signal is obtained. That is, a focus error signal having a waveform as indicated by W703 in FIG. 7 is output in the vicinity of timing T12.

At timing T13, the focal point of the red laser light passes through the information surface (the surface on which information is recorded) of the DVD, and a focus error signal is obtained based on the signal from the red laser light detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W702 in FIG. 7 is output in the vicinity of timing T13. When the amplitude of the focus error signal obtained at this time exceeds a certain level L3, the disc discrimination controller (disc discriminator) 51 discriminates that the loaded disc is a DVD.
If it is determined that the disc loaded in the optical disc apparatus 200 is a DVD, the disc discrimination controller (disc discriminator) 51 ends the disc discrimination operation.
(2.2.2: Disc discriminating operation (in the case of HD-DVD)
Next, with reference to FIG. 6 and FIG. 8, the operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 200 is an HD-DVD will be described in detail.

FIG. 6A shows simultaneous light emission of an HD-DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 facing the objective lens 29), and a blue laser and a red laser. It is a schematic diagram which shows the converged laser beam.
FIG. 8 shows an objective lens position and a focus error signal when the objective lens 29 is driven in a state where blue laser light and red laser light are simultaneously emitted from the HD-DVD.
FIG. 8 (1) is a diagram showing the relationship between time and the position of the objective lens 29, where the horizontal axis is time and the vertical axis is the position of the objective lens 29. Specifically, FIG. 8A shows a position signal of the objective lens 29 when the red laser light and the blue laser light are simultaneously emitted to bring the objective lens 29 close to the HD-DVD.

FIG. 8B is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 8B shows a servo signal generation circuit (servo signal generation unit) 56 when the objective lens 29 is brought close to the HD-DVD by simultaneously emitting red laser light and blue laser light. A focus error signal generated from the output of the blue laser light detector 25 is shown.
FIG. 8 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 8 (3) shows a servo signal generation circuit (servo signal generation unit) 56 when the objective lens 29 is brought close to the HD-DVD by simultaneously emitting red laser light and blue laser light. A focus error signal (corresponding to a signal transmitted through the signal line P2 in FIG. 5) generated from the output of the red laser light detector 24 is shown.

  At the disc discrimination start timing T14, the disc discrimination controller (disc discriminator) 51 starts the disc discrimination operation. The disc discriminating controller (disc discriminating unit) 51 outputs a signal for laser driving amplified by the LDD 40 by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The LDD 40 switches the emission laser selection SW 41 (switches to the c side of the emission laser selection SW 41), and the LDD 40 multiplies the recording emission driving signal by the gain of the simultaneous emission gain amplifier 44 so that the laser driving signal amplified is blue. The recording light emission drive signal switch SW43 of the LDD 40 is switched so as to output to the laser light source 17 (switched to the b side of the recording light emission drive signal switch SW43). Here, since the b side of the recording light emission drive signal switching SW 43 is selected, nothing is output from the recording light emission drive signal gain amplifier 45. Therefore, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW41.

  Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 40), and the recording light emission drive signal such that the output of the blue laser light source 17 becomes a predetermined reproduction laser output level is output to the LDD 40 (specific In this case, the laser light is output to the simultaneous light emission gain amplifier 44) via the recording light emission drive signal switching SW 43 of the LDD 40, so that the red laser light and the blue laser light are simultaneously irradiated. Further, the disc discrimination controller (disc discriminator) 51 raises the position of the objective lens 29 by giving a drive signal to the focus actuator 34 (moves the objective lens 29 in the direction in which the distance from the optical disc 1 is reduced).

As shown in FIG. 6, the objective lens 29 has an optical characteristic that the focal length of the red laser light is longer than the focal length of the blue laser light.
At timing T15, the focus of the red laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lens 29), and the focus error signal is based on the signal from the detector 24 for red laser light when passing. Is obtained. That is, a focus error signal having a waveform as indicated by W801 in FIG. 8 is output in the vicinity of timing T15.
As shown in FIG. 6A, the objective lens 29 in which the focal point of the red laser beam is focused on the far side in the normal direction (the optical axis direction of the objective lens 29) with respect to the objective lens 29 from the focal point of the blue laser beam. Therefore, at the timing T16, the focal point of the blue laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lens 29), and from the blue laser light detector 25 during the passage. A focus error signal is obtained based on the signal. That is, a focus error signal having a waveform as indicated by W803 in FIG. 8 is output in the vicinity of timing T16.

At timing T17, the focal point of the red laser beam passes through the information surface (the surface on which information is recorded) of the HD-DVD, and a focus error signal is obtained based on the signal from the red laser beam detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W802 in FIG. 8 is output in the vicinity of timing T17. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L3, the disc discrimination controller (disc discriminator) 51 continues the disc discrimination operation.
At timing T18, the focal point of the blue laser light passes through the information surface (the surface on which information is recorded) of the HD-DVD, and a focus error signal is obtained based on the signal from the blue laser light detector 25 at the time of passage. That is, a focus error signal having a waveform as indicated by W804 in FIG. 8 is output in the vicinity of timing T18. When the amplitude of the focus error signal obtained at this time exceeds a certain level L4, the disc discrimination controller (disc discriminator) 51 determines that the loaded disc is an HD-DVD.

If it is determined that the disc loaded in the optical disc apparatus 200 is an HD-DVD, the disc discrimination controller (disc discriminator) 51 ends the disc discrimination operation.
As described above, a plurality of types of discs in which the thickness of the base material from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lens 29) to the information surface is substantially equal and the corresponding laser wavelengths are different. In an optical disc apparatus for recording or reproducing, since plural types of discs are discriminated by only moving the objective lens (driving operation to move the objective lens closer to or away from the optical disc) while simultaneously emitting plural types of lasers having different wavelengths. The time required to distinguish the type can be shortened.
Further, the objective lens 29 is used in which the focal point of the long-wavelength red laser beam is focused farther in the normal direction (the optical axis direction of the objective lens 29) than the focal point of the blue laser beam having the short wavelength. Thus, when the red laser light is focused on the DVD information surface, the blue laser light on the DVD information surface is blurred (because the blue laser light is out of focus), so the recorded information on the DVD information surface Can prevent destruction.

In addition, as long as two types of laser light having different wavelengths are used, laser light having any wavelength is not limited to red laser light and blue laser light.
Further, three or more types of lasers having different wavelengths may be used.
In the present embodiment, an example of discriminating the type of the disc loaded in the optical disc apparatus 200 has been shown. However, when one disc has a plurality of information surfaces with different recording densities and corresponding laser wavelengths, You may make it discriminate | determine whether it is a disc with the kind of information surface.
In this embodiment, the front light monitor is provided for each laser wavelength. However, the front light monitor may be provided to irradiate the laser at a low output.
In the present embodiment, the objective lens 29 is used in which the focal point of the red laser beam is focused on the side farther in the normal direction (the optical axis direction of the objective lens 29) than the focal point of the blue laser beam. As an example, the objective lens 29 is used in which the focal point of the red laser beam is closer to the side closer to the normal direction (the optical axis direction of the objective lens 29) than the focal point of the blue laser beam. The position of the objective lens 29 during the disc discrimination operation may be moved away from the vicinity of the surface of the optical disc 1.

Further, when laser emission is performed with a recording light emission driving signal at the time of disc discrimination, a high frequency may be superimposed on the recording light emission driving signal.
In this embodiment, the laser light source to be controlled by the reproduction light emission drive signal and the recording light emission drive signal at the time of disc discrimination is fixed, but may be freely selected.
[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS.
<3.1 Configuration of Optical Disc Device>
FIG. 9 is a block diagram showing a configuration of the optical disc apparatus 300 according to the present embodiment.
The optical disc apparatus 300 includes a red laser light source 12, a red laser light beam splitter 14, a red laser light front light monitor 16, a blue laser light source 17, a blue laser light beam splitter 18, a blue laser light front light monitor 19, and a blue light source. Laser light detector 25, red laser light detector 24, servo signal generation circuit (servo signal generation unit) 56, light emission laser selection SW41, reproduction light emission drive signal gain laser controller (laser control unit) 54, disk discrimination controller (disk discrimination) Part) 51, a recording light emission drive signal switching SW 43, a simultaneous light emission gain amplifier 44, and a recording light emission drive signal gain amplifier 45 amplifier.

Further, the optical disc apparatus 300 includes a red laser beam objective lens 30, a blue laser beam objective lens 31, a red laser beam irradiation beam splitter 27, a blue laser beam irradiation beam splitter 28, a drive difference adding unit 58, a red laser beam. Focus actuator 36 and blue laser light focus actuator 35.
In FIG. 9, an optical disk 1, a red laser light source 12, a red laser light beam splitter 14, a red laser light front light monitor 16, a blue laser light source 17, a blue laser light beam splitter 18, and a blue laser light front light monitor 19. , Blue laser light detector 25, red laser light detector 24, servo signal generation circuit (servo signal generation unit) 56, light emission laser selection SW 41, reproduction light emission drive signal gain laser controller (laser control unit) 54, disk discrimination controller ( The disc discriminating section) 51, the recording light emission drive signal switching SW 43, the simultaneous light emission gain amplifier 44, and the recording light emission drive signal gain amplifier 45 have functions equivalent to those of the background art and the optical disc apparatus of the above-described embodiment. Detailed explanation is omitted.

The background art and the above-described embodiment are different from the objective lens 30 for red laser light, the objective lens 31 for blue laser light, the beam splitter 27 for irradiating red laser light, the beam splitter 28 for irradiating blue laser light, and a drive difference adding unit. 58, by using the red laser light focus actuator 36 and the blue laser light focus actuator 35, it is possible to discriminate a plurality of disc types in a short time with a single objective lens operation while simultaneously emitting multiple wavelengths of laser, Moreover, destruction of recorded information on the information side can be avoided more safely.
The blue laser light source 17 emits blue laser light having a wavelength of about 405 [nm]. The blue laser beam splitter 18 splits the blue laser beam into the blue laser beam irradiation beam splitter 28 and the blue laser beam front light monitor 19. The blue laser light front light monitor 19 detects the output power of the emitted blue laser light. The output of the blue laser light front light monitor 19 is input to the laser controller 54.

The blue laser light split by the blue laser light irradiation beam splitter 28 is reflected by the blue laser light irradiation beam splitter 28 in the direction of the blue laser light objective lens 31 and is reflected by the blue laser light objective lens 31 on the optical disc 1. It is converged on the information surface. The blue laser light reflected by the optical disk 1 passes through the blue laser light irradiation beam splitter 28 and is irradiated to the blue laser light detector 25.
The red laser light source 12 emits red laser light having a wavelength of about 650 [nm]. The red laser beam splitter 14 splits the red laser beam into the red laser beam irradiation beam splitter 27 and the red laser beam front light monitor 16. The red laser light front light monitor 16 detects the output power of the irradiated red laser light. The output of the red laser light front light monitor 16 is input to the laser control unit 54.

The red laser beam dispersed by the red laser beam irradiation beam splitter 27 is reflected by the red laser beam irradiation beam splitter 27 in the direction of the red laser beam objective lens 30, and is reflected by the red laser beam objective lens 30. It is converged on the information surface. The red laser light reflected by the optical disk 1 passes through the red laser light irradiation beam splitter 27 and is irradiated to the red laser light detector 24.
The blue laser light objective lens 31 is driven by a blue laser light focus actuator 35. The red laser light objective lens 30 is driven by a red laser light focus actuator 36.
The laser controller (laser controller) 54 detects the red laser output (red laser light output power level) detected by the red laser light front light monitor 16 and the blue laser light front light monitor 19 during reproduction. A reproduction light emission driving signal is output to the LDD 40 so that the blue laser output (the level of the output power of the blue laser light) is a predetermined reproduction laser output level. The laser controller (laser controller) 54 also records the red laser output (red laser light output power level) detected by the red laser light front light monitor 16 and the blue laser light front light monitor 19 during recording. The reproduction light emission drive signal and the recording light emission drive signal are output to the LDD 40 so that the blue laser output (the level of the output power of the blue laser light) detected in step 1 becomes a predetermined recording laser output level.

The LDD 40 outputs a signal for laser driving amplified by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the blue laser light source 17 or the red laser light source 12 during reproduction. During recording, the LDD 40 multiplies the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 and the amplified laser drive signal and the recording light emission drive signal by the gain of the recording light emission drive signal gain amplifier 45. A signal for driving the laser obtained by adding the signals for driving the laser is output to the blue laser light source 17 or the red laser light source 12.
The recording light emission drive signal switching SW 43 of the LDD 40 is normally set to connect the recording light emission drive signal to the recording light emission drive signal gain amplifier 45. The recording light emission drive signal switching SW 43 receives the output from the laser control unit 54 and inputs an input based on a control signal from the disc discrimination unit 51 (a signal indicating whether or not the disc discrimination operation is being performed). This is a changeover switch that outputs to the recording light emission drive signal gain amplifier 45 or the simultaneous light emission gain amplifier 44. Specifically, the recording light emission drive signal switching SW 43 outputs the input to the simultaneous light emission gain amplifier 44 only during the period in which the disc discrimination operation is being executed, and the input is used for the recording light emission drive signal gain during the other periods. The amplifier 45 is made to output.

The disc discriminating controller (disc discriminating unit) 51 outputs a signal for laser driving amplified by the LDD 40 by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The LDD 40 is switched so that the LDD 40 switches the light emitting laser selection SW 41, and the LDD 40 multiplies the recording light emission driving signal by the gain of the simultaneous light emission gain amplifier 44 to output the amplified laser driving signal to the blue laser light source 17. The light emission drive signal switch SW43 is switched.
When performing the disc discrimination operation, the disc discrimination controller (disc discrimination unit) 51 sets the light emission laser selection SW 41 so that the LDD 40 outputs the reproduction light emission drive signal amplified by the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The recording light emission drive signal switching SW 43 is switched so that the LDD 40 outputs the recording light emission drive signal amplified by the simultaneous light emission gain amplifier 44 to the blue laser light source 17 (switching the light emission laser selection SW 41 to the c side) ( The recording light emission drive signal switch SW43 is switched to the b side). As a result, the optical disc apparatus 300 can emit the red laser beam and the blue laser beam at the same time and irradiate the optical disc 1.

Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal for controlling the output of the red laser light source 12 and the output of the blue laser light source 17 to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40, and a recording light emission drive signal is output to the LDD 40 so that the output of the blue laser light source 17 becomes a predetermined reproduction laser output level, thereby simultaneously irradiating the red laser light and the blue laser light.
The disc discrimination controller (disc discriminating unit) 51 outputs a drive signal for driving the blue laser beam objective lens 31 and the red laser beam objective lens 30 in the vertical direction (distance driving) and the drive difference adding unit 58 and the blue laser beam. Output to the focus actuator 35. The drive difference adder 58 adds a signal of a predetermined level to the drive output (drive signal) from the disc discrimination controller (disc discriminator) 51 and outputs the signal to the red laser light focus actuator 36.

The servo signal generation circuit (servo signal generation unit) 56 generates a servo signal from the outputs from the red laser light detector 24 and the blue laser light detector 25 and outputs the servo signal to the disc determination unit 51. The disc discrimination controller (disc discriminating unit) 51 discriminates the type of the loaded disc based on the servo signal generated by the servo signal generation circuit (servo signal generation unit) 56.
In the LDD 40, the recording light emission drive signal gain amplifier 45 amplifies the drive signal by using the simultaneous light emission gain amplifier 44 for the recording / reproduction drive signal because the amplification factor is too high for the reproduction laser light emission and the resolution is rough. To do. That is, the blue laser light source 17 is driven using the recording / reproducing drive signal amplified by the simultaneous emission gain amplifier 44 having an amplification factor suitable for reproducing laser light emission.

The first adder 401, the second adder 402, the recording light emission drive signal switching SW 43, and the light emission laser selection SW 41 are the same as those described in the above-described embodiment, and thus detailed description thereof is omitted.
<3.2: Operation of Optical Disc Device>
(3.2.1: Disc discriminating operation (in the case of DVD))
Next, with reference to FIG. 10 and FIG. 11, the operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 300 is a DVD will be described in detail.
FIG. 10B shows a DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lenses 30 and 31), blue laser light and red laser light. It is a schematic diagram which shows the laser beam simultaneously emitted and converged.

In FIG. 11, in the optical disc apparatus 300, the red color when the blue laser light objective lens 31 and the red laser light objective lens 30 are driven in a state where the blue laser light and the red laser light are simultaneously emitted from the DVD. The laser light objective lens position and the focus error signal are shown.
FIG. 11 (1) is a diagram showing the relationship between time and the position of the red laser light objective lens 30, with the horizontal axis representing time and the vertical axis representing the position of the red laser light objective lens 30. Specifically, FIG. 11 (1) shows the red laser light when the red laser light and the blue laser light are simultaneously emitted to bring the blue laser light objective lens 31 and the red laser light objective lens 30 closer to the DVD. The position signal of the objective lens 30 is shown.
FIG. 11 (2) is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 11B shows a servo signal when the red laser light and the blue laser light are simultaneously emitted to bring the blue laser light objective lens 31 and the red laser light objective lens 30 closer to the DVD. A focus error signal (corresponding to a signal transmitted through the signal line P1 in FIG. 9) generated from the output of the red laser light detector 24 by the generation circuit (servo signal generation unit) 56 is shown.

FIG. 11 (3) is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 11 (3) shows a servo signal when the red laser light and the blue laser light are simultaneously emitted to bring the blue laser light objective lens 31 and the red laser light objective lens 30 closer to the DVD. A focus error signal (corresponding to a signal transmitted by the signal line P2 in FIG. 9) generated from the output of the blue laser light detector 25 by the generation circuit (servo signal generation unit) 56 is shown.
At the disc discrimination start timing T19, the disc discriminator controller (disc discriminator) 51 starts the disc discrimination operation. The disc discriminating controller (disc discriminating unit) 51 outputs a signal for laser driving amplified by the LDD 40 by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The LDD 40 switches the emission laser selection SW 41 (switches to the c side of the emission laser selection SW 41), and the LDD 40 multiplies the recording emission driving signal by the gain of the simultaneous emission gain amplifier 44 so that the laser driving signal amplified is blue. The recording light emission drive signal switch SW43 of the LDD 40 is switched so as to output to the laser light source 17 (switched to the b side of the recording light emission drive signal switch SW43). Here, since the b side of the recording light emission drive signal switching SW 43 is selected, nothing is output from the recording light emission drive signal gain amplifier 45. Therefore, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW41.

  Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 40), and the recording light emission drive signal such that the output of the blue laser light source 17 becomes a predetermined reproduction laser output level is output to the LDD 40 (specific In this case, the laser light is output to the simultaneous light emission gain amplifier 44) via the recording light emission drive signal switching SW 43 of the LDD 40, so that the red laser light and the blue laser light are simultaneously irradiated. Further, the disc discrimination controller (disc discriminator) 51 outputs a drive signal for raising the positions of the blue laser light objective lens 31 and the red laser light objective lens 30.

The red laser light focus actuator 36 uses a drive signal obtained by adding a predetermined drive amount by the drive difference adder 58 to the drive signal output from the disk discriminating controller (disk discriminating unit) 51, and thereby the red laser beam objective lens. 30 is raised (the objective lens 30 for red laser light is moved closer to the optical disc 1).
Further, the blue laser light focus actuator 35 raises the blue laser light objective lens 31 (the blue laser light objective lens 31 is attached to the optical disk 1) by the drive signal output from the disk discrimination controller (disk discrimination unit) 51. Approach).
At timing T20, the focus of the red laser light passes through the surface of the DVD (the surface of the optical disc 1 on the side facing the objective lenses 30 and 31), and the focus error signal is based on the signal from the detector 24 for red laser light when passing. Is obtained. That is, a focus error signal having a waveform as indicated by W111 in FIG. 11 is output in the vicinity of timing T20.

  As shown in FIG. 10B, the focal point of the red laser beam is normal to the objective lens 30 for the red laser beam and the objective lens 31 for the blue laser beam than the focal point of the blue laser beam (the objective for the red laser beam). In order to set a drive offset value in the drive difference adder 58 so as to focus on the far side in the optical axis direction of each of the lens 30 and the blue laser light objective lens 31, the focus of the blue laser light is set at timing T21. A focus error signal is obtained based on the signal from the blue laser light detector 25 when passing through the surface of the DVD (the surface of the optical disc 1 on the side facing the objective lenses 30 and 31). That is, a focus error signal having a waveform as indicated by W113 in FIG. 11 is output in the vicinity of timing T21. The time difference between T21 and T20 in FIG. 11 is the drive offset value set in the drive difference adder 58, the speed at which the red laser light objective lens 30 and the blue laser light objective lens 31 are brought closer to the optical disc 1. And the focal length of the red laser light objective lens 30 and the blue laser light objective lens 31 (normally, the speed at which the red laser light objective lens 30 approaches the optical disc 1 and the blue laser light objective lens 31). Is the same as the speed of approaching the optical disc 1).

At timing T22, the focal point of the red laser beam passes through the information surface of the DVD, and a focus error signal is obtained based on the signal from the red laser beam detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W112 in FIG. 11 is output in the vicinity of the timing T22. When the amplitude of the focus error signal obtained at this time exceeds a certain level L5, the disc discrimination controller (disc discriminator) 51 discriminates that the loaded disc is a DVD.
If it is determined that the disk loaded in the optical disk apparatus 300 is a DVD, the disk determination controller (disk determination unit) 51 ends the disk determination operation.
(3.2.2: Disc discriminating operation (in the case of HD-DVD))
Next, with reference to FIG. 10 and FIG. 12, an operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 300 is an HD-DVD will be described in detail.

FIG. 10A shows an HD-DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 facing the objective lenses 30 and 31), a blue laser beam, and a red laser. It is a schematic diagram which shows the laser beam which light-emitted and converged light simultaneously.
In FIG. 12, when the blue laser light objective lens 31 and the red laser light objective lens 30 are driven in the optical disc apparatus 300 in a state where blue laser light and red laser light are simultaneously emitted from the HD-DVD. The objective lens position for red laser light and the focus error signal are shown.
FIG. 12A is a diagram showing the relationship between time and the position of the red laser light objective lens 30 with the horizontal axis representing time and the vertical axis representing the position of the red laser light objective lens 30. Specifically, FIG. 12A shows the red color when the red laser beam and the blue laser beam are simultaneously emitted to bring the blue laser beam objective lens 31 and the red laser beam objective lens 30 closer to the HD-DVD. The position signal of the laser light objective lens 30 is shown.

FIG. 12B is a diagram illustrating the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 12 (2) shows a case where the blue laser light objective lens 31 and the red laser light objective lens 30 are brought close to the HD-DVD by simultaneously emitting red laser light and blue laser light. A focus error signal (corresponding to a signal transmitted through the signal line P1 in FIG. 9) generated from the output of the red laser light detector 24 by the servo signal generation circuit (servo signal generation unit) 56 is shown.
FIG. 12 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 12 (3) shows a case where the blue laser light objective lens 31 and the red laser light objective lens 30 are brought close to the HD-DVD by simultaneously emitting red laser light and blue laser light. A focus error signal (corresponding to a signal transmitted by the signal line P2 in FIG. 9) generated from the output of the blue laser light detector 25 by the servo signal generation circuit (servo signal generation unit) 56 is shown.

  At the disc discrimination start timing T23, the disc discriminator controller (disc discriminator) 51 starts the disc discrimination operation. The disc discriminating controller (disc discriminating unit) 51 outputs a signal for laser driving amplified by the LDD 40 by multiplying the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 to the red laser light source 12. The LDD 40 switches the emission laser selection SW 41 (switches to the c side of the emission laser selection SW 41), and the LDD 40 multiplies the recording emission driving signal by the gain of the simultaneous emission gain amplifier 44 so that the laser driving signal amplified is blue. The recording light emission drive signal switch SW43 of the LDD 40 is switched so as to output to the laser light source 17 (switched to the b side of the recording light emission drive signal switch SW43). Here, since the b side of the recording light emission drive signal switching SW 43 is selected, nothing is output from the recording light emission drive signal gain amplifier 45. Therefore, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW41.

Further, the disk discrimination controller (disk discrimination unit) 51 outputs a laser control mode switching signal to the laser controller (laser control unit) 54. When the laser controller (laser control unit) 54 receives a laser control mode switching signal from the disc discrimination controller (disc discriminator) 51, a reproduction light emission drive signal that causes the output of the red laser light source 12 to reach a predetermined reproduction laser output level. Is output to the LDD 40 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 40), and the recording light emission drive signal such that the output of the blue laser light source 17 becomes a predetermined reproduction laser output level is output to the LDD 40 (specific In this case, the red laser light and the blue laser light are simultaneously irradiated by outputting to the gain amplifier 44 for simultaneous light emission via the recording light emission drive signal switching SW 43 of the LDD 40.
Further, the disc discrimination controller (disc discriminator) 51 outputs a drive signal for raising the positions of the blue laser beam objective lens 31 and the red laser beam objective lens 30.

The red laser light focus actuator 36 uses a drive signal obtained by adding a predetermined drive amount by the drive difference adder 58 to the drive signal output from the disk discriminating controller (disk discriminating unit) 51, and thereby the red laser beam objective lens. 30 is raised (the objective lens 30 for red laser light is moved closer to the optical disc 1).
Further, the blue laser light focus actuator 35 raises the blue laser light objective lens 31 (the blue laser light objective lens 31 is attached to the optical disk 1) by the drive signal output from the disk discrimination controller (disk discrimination unit) 51. Approach).
At timing T24, the focal point of the red laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 30 and 31), and is focused based on the signal from the detector 24 for red laser light when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W121 in FIG. 12 is output in the vicinity of timing T24.

As shown in FIG. 10A, the focus of the red laser light is normal to the red laser light objective lens 30 and the blue laser light objective lens 31 (the red laser light objective is more focused than the blue laser light focus). In order to set a drive offset value in the drive difference adding unit 58 so as to focus on the far side in the optical axis direction of each of the lens 30 and the blue laser light objective lens 31, the focus of the blue laser light is set at timing T25. A focus error signal is obtained based on a signal from the blue laser light detector 25 when passing through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 30 and 31). That is, a focus error signal having a waveform as indicated by W123 in FIG. 12 is output in the vicinity of timing T25.
At timing T26, the focal point of the red laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the red laser light detector 24 at the time of passage. That is, a focus error signal having a waveform as indicated by W122 in FIG. 12 is output in the vicinity of timing T26. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L5, the disc discrimination controller (disc discriminator) 51 continues the disc discrimination operation.

At timing T27, the focal point of the blue laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the blue laser light detector 25 at the time of passage. That is, a focus error signal having a waveform as indicated by W124 in FIG. 12 is output in the vicinity of timing T27. When the amplitude of the focus error signal obtained at this time exceeds a certain level L6, the disc discrimination controller (disc discriminator) 51 discriminates that the loaded disc is an HD-DVD.
If it is determined that the disc loaded in the optical disc apparatus 300 is an HD-DVD, the disc discrimination controller (disc discriminator) 51 ends the disc discrimination operation.
As described above, the thickness of the base material from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lenses 30 and 31) to the information surface is substantially equal, and a plurality of types with different corresponding laser wavelengths are used. In an optical disk device that records or reproduces a disk, multiple types of disks are discriminated by moving the objective lens (driving the objective lens closer to or away from the optical disk) while simultaneously emitting multiple types of lasers having different wavelengths. The time required for disc type determination can be shortened.

Further, the objective lens has two objective lenses (the objective lens 30 for red laser light and the objective lens 31 for blue laser light) so that they can be driven separately. Further, it is driven between both objective lenses so as to focus on the far side in the normal direction (the respective optical axis directions of the red laser light objective lens 30 and the blue laser light objective lens 31) with respect to the objective lenses 30 and 31. By giving the difference, when the red laser light is focused on the DVD information surface, the blue laser light on the DVD information surface is blurred (because the blue laser light is out of focus). Can prevent the destruction of recorded information.
In addition, because it has two objective lenses (objective lenses 30 and 31) and can be driven separately, the difference in focus between the two objective lenses can be manipulated freely (the focal position of the two objective lenses can be set freely) Therefore, destruction of recorded information on the information surface can be prevented more safely than a single objective lens.

In addition, as long as two types of laser light having different wavelengths are used, laser light having any wavelength is not limited to red laser light and blue laser light.
Further, three or more types of laser beams having different wavelengths may be used.
In the present embodiment, an example of discriminating the type of the disc loaded in the optical disc apparatus 300 has been shown. However, when one disc has a plurality of information surfaces with different recording densities and corresponding laser wavelengths, You may make it discriminate | determine whether it is a disc with the kind of information surface.
In this embodiment, the front light monitor is provided for each laser wavelength. However, the front light monitor may be provided to irradiate the laser at a low output.
In the present embodiment, the focal point of the red laser light is normal to the objective lenses 30 and 31 from the focal point of the blue laser light (respective lights of the objective lens 30 for red laser light and the objective lens 31 for blue laser light). Although an example in which a drive offset value that focuses on the far side in the axial direction) is set in the drive difference adding unit 58 has been shown, the focus of the red laser light is greater than that of the blue laser light with respect to the objective lenses 30 and 31. A drive offset value that focuses on the side closer to the normal direction (the optical axis direction of each of the red laser light objective lens 30 and the blue laser light objective lens 31) is set in the drive difference adder 58 to discriminate the disc. The positions of the blue laser light objective lens 31 and the red laser light objective lens 30 during operation may be moved away from the vicinity of the surface of the optical disc 1. .

Further, when laser emission is performed with a recording light emission driving signal at the time of disc discrimination, a high frequency may be superimposed on the recording light emission driving signal.
In this embodiment, the laser light source to be controlled by the reproduction light emission drive signal and the recording light emission drive signal at the time of disc discrimination is fixed, but may be freely selected.
[Fourth Embodiment]
A fourth embodiment will be described with reference to FIGS.
<4.1: Configuration of Optical Disc Device>
FIG. 13 is a block diagram showing a configuration of the optical disc apparatus 400 according to the present embodiment.
The optical disc apparatus 400 mainly includes an optical head 4010, an LDD 4040, a laser control unit 55, a servo signal generation unit 57, a disc determination unit 52, and a drive difference addition unit 58.

The optical head 4010 mainly includes an infrared laser light source 11, an infrared laser light beam splitter 13, an infrared laser light front light monitor 15, a red laser light source 12, a red laser light beam splitter 14, and a red laser light. Front light monitor 16, blue laser light source 17, blue laser light beam splitter 18, blue laser light front light monitor 19, irradiation beam splitter 20, detector beam splitter 21, detector beam splitter 22, optical path switch 39, Infrared laser light detector 23, red laser light detector 24, blue laser light detector 25, blue laser light detector 26, high NA objective lens 32, low NA objective lens 33, high NA focus actuator 37, and low The focus actuator 38 for NA is comprised.
The LDD 4040 mainly includes a reproduction light emission drive signal gain amplifier 42, a recording light emission drive signal gain amplifier 45, a simultaneous light emission gain amplifier 44, a recording light emission drive signal switching SW 43, a simultaneous light emission gain amplifier 47, and a recording light emission drive signal gain amplifier 48. , Recording light emission drive signal switching SW 46, light emission laser selection SW 49, first adder 401, second adder 402, third adder 403, and fourth adder 404.

In addition, the same number is attached | subjected about what has the same function as background art and the above-mentioned embodiment, and detailed description is abbreviate | omitted.
In this embodiment, the background art and the above-described embodiments are different from each other in that a laser controller (laser control unit) 55, a servo signal generation unit 57, a disk discrimination unit 52, an optical head 4010, and an LDD 4040 are used. A small number of objective lens operations (driving operation to move the objective lens closer to or away from the optical disk 1) while simultaneously emitting lasers allows a plurality of disc types to be distinguished in a short time, and more reliably destroys recorded information on the information surface. It can be avoided. In particular, by using the high NA objective lens 32 and the low NA objective lens 33 provided in the optical head 4010, a small number of objective lens operations (the objective lenses 32 and 33 are brought close to the optical disk while simultaneously emitting a plurality of wavelengths of laser light, In other words, it is possible to discriminate between a plurality of disc types in a short time and to prevent the recorded information destruction on the information surface more reliably.

The blue laser light source 17 emits blue laser light having a wavelength of about 405 [nm]. The blue laser beam splitter 18 splits the blue laser beam into the optical path switch 39 and the blue laser beam front light monitor 19. The blue laser light front light monitor 19 detects the output power of the emitted blue laser light. The output of the blue laser light front light monitor 19 is input to the laser controller 55.
When the optical path switch 39 is in the ON state, the blue laser light irradiated to the optical path switch 39 is irradiated to the high NA objective lens 32 and converged on the information surface of the optical disc 1 by the high NA objective lens 32. The blue laser light reflected by the optical disk 1 passes through the optical path switch 39 and is applied to the blue laser light detector 25. When the optical path switch 39 is in the OFF state, the blue laser light applied to the optical path switch 39 is The beam splitter 20 for irradiation is irradiated. The blue laser light applied to the irradiation beam splitter 20 is applied to the low NA objective lens 33 by the irradiation beam splitter 20 and converged on the information surface of the optical disc 1 by the low NA objective lens 33. The blue laser light reflected by the optical disk 1 passes through the irradiation beam splitter 20 and the detector beam splitter 21 and is irradiated to the blue laser light detector 26.

For example, the optical path switch 39 inserts the beam splitter into the optical path of the laser beam (position 39 in FIG. 13) in the ON state, and retracts the beam splitter outside the optical path of the laser beam in the OFF state. (Equivalent to making nothing exist at the position 39 in FIG. 13).
The red laser light source 12 emits a red laser having a wavelength of about 650 [nm]. The red laser beam splitter 14 splits the red laser beam into the irradiation beam splitter 20 and the red laser beam front light monitor 16. The red laser light front light monitor 16 detects the output power of the irradiated red laser. The output of the red laser light front light monitor 16 is input to the laser control unit 55.
The red laser light split by the irradiation beam splitter 20 is irradiated to the low NA objective lens 33 by the irradiation beam splitter 20 and converged on the information surface of the optical disc 1 by the low NA objective lens 33. The red laser beam reflected by the optical disk 1 passes through the irradiation beam splitter 20 and is irradiated to the red laser beam detector 24 by the detector beam splitter 22.

The infrared laser light source 11 irradiates an infrared laser having a wavelength of about 780 [nm]. The infrared laser beam splitter 13 splits the infrared laser beam into the irradiation beam splitter 20 and the infrared laser beam front light monitor 15. The infrared laser light front light monitor 15 detects the output power of the irradiated infrared laser. The output of the infrared laser light front light monitor 15 is input to the laser control unit 55.
The infrared laser beam split by the irradiation beam splitter 20 is irradiated to the low NA objective lens 33 by the irradiation beam splitter 20 and converged on the information surface of the optical disc 1 by the low NA objective lens 33. The infrared laser light reflected by the optical disk 1 passes through the irradiation beam splitter 20 and is irradiated to the infrared laser light detector 23 by the detector beam splitter 21.

The high NA objective lens 32 is driven by a high NA focus actuator 37.
The low NA objective lens 33 is driven by a low NA focus actuator 38.
The laser controller (laser controller) 55 detects the blue laser output (the level of the output power of the blue laser light) detected by the blue laser light front light monitor 19 and the red laser light front light monitor 16 during reproduction. The red laser output (the level of the output power of the red laser light) and the infrared laser output (the level of the output power of the infrared laser light) detected by the infrared laser light front light monitor 15 are a predetermined reproduction laser output. A reproduction light emission drive signal that reaches a level is output to the LDD 4040. During recording, the laser controller 55 detects the blue laser output detected by the blue laser light front light monitor 19, the red laser output detected by the red laser light front light monitor 16, and the infrared laser light front light monitor 15. The reproduction light emission drive signal, the first recording light emission drive signal, and the second recording light emission drive signal are output to the LDD 4040 so that the infrared laser output detected in step S becomes a predetermined recording laser output level.

At the time of reproduction, the LDD 4040 multiplies the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42, and outputs the amplified laser drive signal to the blue laser light source 17, the red laser light source 12, or the infrared laser light source 11. (In the laser emission selection SW49, if the c side is selected, the laser is driven to the blue laser light source, if the d side is selected, the red laser light source is selected, and if the e side is selected, the infrared laser light source is driven. Can be output).
In recording, the LDD 4040 multiplies the reproduction light emission drive signal by the gain of the reproduction light emission drive signal gain amplifier 42 and amplifies the laser drive signal, and the first recording light emission drive signal gains the recording light emission drive signal gain amplifier 45. The laser drive obtained by adding the signal for laser driving amplified by multiplying the signal for driving the laser amplified by multiplying the second recording light emission driving signal by the gain of the recording light emission driving signal gain amplifier 48. Is output to the blue laser light source 17, the red laser light source 12, or the infrared laser light source 11 (if the c side is selected in the light emission laser selection SW49, the blue laser light source is selected and the d side is selected. If the e side is selected for the red laser light source, a signal for laser drive can be output to the infrared laser light source). In this case, the a side is selected in the recording light emission drive signal switch SW43, and the f side is selected in the recording light emission drive signal switch SW46.

The recording light emission drive signal switching SW 43 of the LDD 4040 is normally set so that the first recording light emission drive signal is connected to the recording light emission drive signal gain amplifier 45 (a side is selected). In general, the second recording light emission driving signal is set to be connected to the recording light emission driving signal gain amplifier 48 (the f side is selected).
The disc discriminating controller (disc discriminating unit) 52 outputs a laser driving signal amplified by the LDD 4040 by multiplying the reproduction light emission driving signal by the gain of the reproduction light emission driving signal gain amplifier 42 to the blue laser light source 17. The LDD 4040 is switched so that the LDD 4040 switches the light emitting laser selection SW 49 and the LDD 4040 outputs a signal for laser driving amplified by multiplying the gain of the simultaneous light emission gain amplifier 44 to the first recording light emission driving signal to the red laser light source 12. The recording light emission drive signal switch SW43 is switched, and the LDD 4040 outputs a signal for laser drive amplified by multiplying the gain of the simultaneous light emission gain amplifier 47 to the second recording light emission drive signal to the infrared laser light source 11. The recording light emission drive signal switching SW 46 of the LDD 4040 is switched to That.

  When performing the disc discrimination operation, the disc discrimination controller (disc discriminator) 52 sets the light emission laser selection SW 49 so that the LDD 4040 outputs the reproduction light emission drive signal amplified by the reproduction light emission drive signal gain amplifier 42 to the blue laser light source 17. The recording light emission drive signal switching SW 43 is switched so that the LDD 4040 outputs the first recording light emission drive signal amplified by the simultaneous light emission gain amplifier 44 to the red laser light source 12. The recording light emission driving signal is switched so that the LDD 4040 outputs the second recording light emission driving signal amplified by the simultaneous light emission gain amplifier 47 to the infrared laser light source 11. The switch SW46 is switched (the recording light emission drive signal switch SW46 is set to the g side). Sort). Thereby, in the optical disc apparatus 400, it is possible to simultaneously emit infrared laser light, red laser light, and blue laser light and irradiate the optical disc 1.

  Further, the disc discrimination controller (disc discriminator) 52 controls the laser controller (laser controller) 55 to control the output of the blue laser light source 17, the output of the red laser light source 12, and the output of the infrared laser light source 11. Outputs a mode switching signal. When the laser controller (laser control unit) 55 receives the laser control mode switching signal from the disc discrimination controller (disc discriminator) 52, a reproduction light emission drive signal that causes the output of the blue laser light source 17 to reach a predetermined reproduction laser output level. Is output to the LDD 4040 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 4040), and the first recording light emission drive signal such that the output of the red laser light source 12 becomes a predetermined reproduction laser output level is output to the LDD 4040 (specific Is output to the simultaneous emission gain amplifier 44) via the recording emission drive signal switch SW43 of the LDD 4040, and a second recording emission drive signal is output so that the output of the infrared laser light source 11 becomes a predetermined reproduction laser output level. LDD 4040 (specifically, via recording light emission drive signal switching SW 46 of LDD 4040) By outputting the simultaneous emission gain amplifier 47), a blue laser light, at the same time is irradiated with red laser light and infrared laser light.

The disc discrimination controller (disc discriminating unit) 52 also outputs a drive signal for driving the high NA objective lens 32 and the low NA objective lens 33 in the vertical direction (distance driving) and the drive difference adding unit 58 and the high NA focus actuator 37. Output to. The drive difference adding unit 58 offsets (adds) a signal of a predetermined level to the drive output (output of the drive signal) from the disc discrimination controller (disc discriminator) 52 and outputs it to the low NA focus actuator 38. .
The disc discrimination controller (disc discriminator) 52 outputs an optical path switching signal for switching the optical path switch 39 to ON or OFF (input / output paths and connection relations are not shown). Then, the optical path switcher switches between the ON state and the OFF state in accordance with the optical path switching signal from the disc determination unit 52.

A servo signal generation circuit (servo signal generation unit) 57 generates a servo signal from outputs from the blue laser light detector 25, the blue laser light detector 26, the red laser light detector 24, and the infrared laser light detector 23. The data is output to the disc discrimination unit 52.
The disk discrimination controller (disk discrimination unit) 52 discriminates the type of the loaded disc based on the servo signal generated by the servo signal generation circuit (servo signal generation unit) 57.
In the LDD 4040, since the recording light emission drive signal gain amplifiers 45 and 48 have an amplification factor that is too high for reproduction laser light emission and the resolution is coarse, the first recording light emission drive signal and the second recording light emission drive signal are used for simultaneous light emission. Gain signals 44 and 47 are used to amplify the drive signal. That is, using the first recording light emission drive signal and the second recording light emission drive signal amplified by the simultaneous light emission gain amplifiers 44 and 47 having an amplification factor suitable for reproducing laser light emission, the red laser light source 12 and the red laser light source 12 The outer laser light source 11 is driven.

The first adder 401, the second adder 402, and the recording light emission drive signal switching SW 43 are the same as those described in the above-described embodiment, and thus detailed description thereof is omitted.
The third adder 403 is the same as the first adder, the fourth adder 404 is the same as the second adder, and the recording light emission drive signal switching SW 46 is a recording light emission drive signal. This is the same as the switch SW43. The light emitting laser selection SW 49 has the same function as the light emitting laser selection SW 41 (selector with one input and two outputs), and differs from the light emitting laser selection SW 41 only in that it is a selector with one input and three outputs.
<4.2: Operation of Optical Disc Device>
(4.2.1: Disc discrimination operation (in the case of HD-DVD))
Next, with reference to FIG. 14 and FIG. 15, the operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 400 is an HD-DVD will be described in detail.

14A shows an HD-DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33) and the high NA objective lens 32. FIG. FIG. 4 is a schematic diagram showing laser light that simultaneously emits and converges red laser light and infrared laser light from a low NA objective lens 33 at the same time as emitting and converging blue laser light.
FIG. 14B shows an HD-DVD having an information surface at a position of about 0.6 mm from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33) and the low NA objective lens 33. It is a schematic diagram which shows the laser beam which emitted and converged the blue laser beam.
FIG. 15 shows a high NA objective in a state where blue laser light is emitted from the high NA objective lens 32 and simultaneously red laser light and infrared laser light are emitted from the low NA objective lens 33 for the HD-DVD. The high NA objective lens 32 and the low NA objective lens 33 when the lens 32 and the low NA objective lens 33 are driven, and a blue laser light is emitted from the low NA objective lens 33 after that. The high NA objective lens position and the focus error signal when the NA objective lens 33 is driven are shown.

FIG. 15 (1) is a diagram showing the relationship between time and the position of the high NA objective lens 32, where the horizontal axis is time and the vertical axis is the position of the high NA objective lens 32. Specifically, FIG. 15A shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. The position signal of the high NA objective lens 32 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD is shown.
FIG. 15B is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 15B shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. A focus error signal (servo signal generation unit) 57 generated from the output of the infrared laser beam detector 23 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD (FIG. 13). Corresponding to the signal transmitted by the signal line P1.

FIG. 15 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 15 (3) shows a state in which blue laser light is emitted from the high NA objective lens 32 and red laser light and infrared laser light are simultaneously emitted from the low NA objective lens 33. A focus error signal (servo signal generator) 57 generated from the output of the red laser beam detector 24 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD (see FIG. 13). This corresponds to a signal transmitted through the signal line P2.).
FIG. 15 (4) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 15 (4) shows a state in which blue laser light is emitted from the high NA objective lens 32 and red laser light and infrared laser light are simultaneously emitted from the low NA objective lens 33. A focus error signal (servo signal generator) 57 generated from the output of the blue laser light detector 25 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD (see FIG. 13). This corresponds to a signal transmitted through the signal line P3.).

FIG. 15 (5) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 15 (5) shows a servo when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the HD-DVD in a state where blue laser light is emitted from the low NA objective lens 33. A focus error signal (corresponding to a signal transmitted by the signal line P4 in FIG. 13) generated from the output of the blue laser light detector 26 by the signal generation circuit (servo signal generation unit) 57 is shown.
FIG. 15 (6) is a diagram showing the relationship between time and the optical path switching signal level, with the horizontal axis representing time and the vertical axis representing the optical path switching signal level. Specifically, FIG. 15 (6) shows a state in which the high NA objective lens 32 emits blue laser light and the low NA objective lens 33 emits red laser light and infrared laser light simultaneously. The blue laser when the high NA objective lens 32 and the low NA objective lens 33 are driven in a state in which the objective lens 32 and the low NA objective lens 33 are driven and then the blue laser light is emitted from the low NA objective lens 33. A state in which light is output from either the high NA objective lens 32 or the low NA objective lens 33 is shown. That is, in FIG. 15 (6), the blue laser light is output from the high NA objective lens 32 during the period from time T28 to T34, and the blue laser light is output from the low NA objective lens during the period after time T34. This indicates that the data is output from 33.

  At the disk determination start timing T28, the disk determination controller (disk determination unit) 52 starts the disk determination operation. The disc discriminating controller (disc discriminating unit) 52 outputs a laser driving signal amplified by the LDD 4040 by multiplying the reproduction light emission driving signal by the gain of the reproduction light emission driving signal gain amplifier 42 to the blue laser light source 17. A signal for laser driving amplified by switching the light emitting laser selection SW 49 of the LDD 4040 (switching to the c side of the light emitting laser selection SW 49) and the LDD 4040 multiplying the gain of the simultaneous light emission gain amplifier 44 by the first recording light emission driving signal. Is switched to the recording light emission drive signal switch SW43 of the LDD 4040 (the recording light emission drive signal switch SW43 is switched to the b side) so that the LDD 4040 outputs the second recording light emission drive signal to the simultaneous light emission gain amplifier 47. The laser drive amplified by multiplying the gain is converted to infrared So as to output the laser light source 11 switches the recording light emission drive signal switching SW46 of LDD4040 (switching the recording light emission drive signal switching SW46 to g side). Here, since the b side of the recording light emission drive signal switch SW 43 and the g side of the recording light emission drive signal switch SW 46 are selected, nothing is output from the recording light emission drive signal gain amplifiers 45 and 48. Accordingly, the output of the first adder 401 becomes the output itself of the reproduction light emission drive signal gain amplifier 42, and is the same as the state where the output of the reproduction light emission drive signal gain amplifier 42 is directly connected to the input of the light emission laser selection SW49.

  Further, the disk discrimination controller (disk discrimination unit) 52 outputs a laser control mode switching signal to the laser controller (laser control unit) 55. When the laser controller (laser control unit) 55 receives the laser control mode switching signal from the disc discrimination controller (disc discriminator) 52, a reproduction light emission drive signal that causes the output of the blue laser light source 17 to reach a predetermined reproduction laser output level. Is output to the LDD 4040 (specifically, the reproduction light emission drive signal gain amplifier 42 of the LDD 4040), and the first recording light emission drive signal such that the output of the red laser light source 12 becomes a predetermined reproduction laser output level is output to the LDD 4040 (specific Is output to the simultaneous emission gain amplifier 44) via the recording emission drive signal switch SW43 of the LDD 4040, and a second recording emission drive signal is output so that the output of the infrared laser light source 11 becomes a predetermined reproduction laser output level. LDD 4040 (specifically, via recording light emission drive signal switching SW 46 of LDD 4040) By outputting the simultaneous emission gain amplifier 47), a blue laser light, at the same time is irradiated with red laser light and infrared laser light.

Further, the disc discrimination controller (disc discriminator) 52 outputs drive signals for raising the positions of the high NA objective lens 32 and the low NA objective lens 33. The high NA focus actuator 37 raises the high NA objective lens 32 by the drive signal output from the disk discrimination controller (disk discrimination unit) 52 (the high NA objective lens 32 is brought closer to the optical disc 1). Further, the low NA focus actuator 38 uses a drive signal obtained by adding a predetermined drive amount by the drive difference adder 58 to the drive signal output from the disk discriminator controller (disc discriminator) 52, and thereby the low NA objective lens 33. (The low NA objective lens 33 is moved closer to the optical disc 1).
At timing T29, the focal point of the infrared laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and is based on the signal from the infrared laser light detector 23 when passing. To obtain a focus error signal. That is, a focus error signal having a waveform as indicated by W151 in FIG. 15 is output in the vicinity of timing T29.

  As shown in FIG. 14A, the focal point of the infrared laser beam is farther in the normal direction (the optical axis direction of the low NA objective lens 33) than the focal point of the red laser beam. Is used, and the focus of the red laser light focused by the low NA objective lens 33 is set to the objective lenses 32 and 33 from the focus of the blue laser light converged by the high NA objective lens 32. In order to set a drive offset value in the drive difference adder 58 so as to focus on the far side in the normal direction (the optical axis direction of each of the objective lenses 32 and 33), the focus of the red laser light is HD− at timing T30. Passes through the surface of the DVD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and a focus error occurs based on the signal from the detector 24 for red laser light when passing. No. is obtained. That is, a focus error signal having a waveform as indicated by W153 in FIG. 15 is output in the vicinity of timing T30.

At timing T31, the focal point of the blue laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 facing the objective lenses 32 and 33), and is based on the signal from the blue laser light detector 25 when passing. To obtain a focus error signal. That is, a focus error signal having a waveform as indicated by W155 in FIG. 15 is output in the vicinity of timing T31. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L9, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
At timing T32, the focal point of the infrared laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the infrared laser light detector 23 at the time of passage. That is, a focus error signal having a waveform as indicated by W152 in FIG. 15 is output in the vicinity of timing T32. Since the amplitude of the focus error signal obtained at this time does not exceed the certain level L7, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.

Next, at timing T33, the focal point of the red laser beam passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the red laser beam detector 24 when passing. That is, a focus error signal having a waveform as indicated by W154 in FIG. 15 is output in the vicinity of timing T33. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L8, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
Since the disc discrimination controller (disc discriminator) 52 continues to raise the high NA objective lens 32 and the low NA objective lens 33, the high NA objective lens 32 or the low NA objective lens 33 is set in advance at timing T34. The position limit is reached. For this reason, the disc discrimination controller (disc discriminating unit) 52 stops raising the high NA objective lens 32 and the low NA objective lens 33 (the driving operation for approaching the optical disc 1), and moves the high NA objective lens 32 and the low NA objective lens 33 to each other. Lower (drive away from the optical disc 1). Then, the positions of the high NA objective lens 32 and the low NA objective lens 33 are returned to the positions at the timing T28 in FIG.

Next, the disk discriminating controller (disk discriminating unit) 52 extinguishes the emitted red laser light and infrared laser light, and outputs the optical path switching signal, thereby turning off the optical path switch 39.
In other words, the disc discrimination controller (disc discriminator) 52 emits blue laser light from the high NA objective lens 32 and simultaneously emits red laser light and red from the low NA objective lens 33 when the objective lens position reaches the position limit. The state is switched from the state in which the external laser light is simultaneously emitted to the state in which the blue laser is emitted from the low NA objective lens 33.
In a state where blue laser light is emitted from the low NA objective lens 33, the disc discrimination controller (disc discrimination unit) 52 raises the high NA objective lens 32 and the low NA objective lens 33 again (closes to the optical disc 1).

At timing T35, the focal point of the blue laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and is focused based on the signal from the blue laser light detector 26 when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W156 in FIG. 15 is output in the vicinity of timing T35.
At timing T36, the focal point of the blue laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the blue laser light detector 26 at the time of passage. That is, a focus error signal having a waveform as indicated by W157 in FIG. 15 is output in the vicinity of timing T36. When the amplitude of the focus error signal obtained at this time exceeds a certain level L10, the disc discrimination controller (disc discriminator) 52 determines that the loaded disc is an HD-DVD.

As described above, the thickness of the base material from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33) to the information surface is substantially equal or different, and the corresponding laser wavelengths are different. In an optical disc device that records or plays back various types of discs, multiple types of discs can be created by moving the objective lens a few times (driving operation to move the objective lens closer to or away from the optical disc) while simultaneously emitting multiple types of lasers with different wavelengths. Since the determination is made, the time required to determine the disc type can be shortened.
Further, by simultaneously discriminating Blu-ray discs and DVDs and CDs in the first half of disc discriminating operation and then discriminating HD-DVDs, the recorded information on the DVD information surface is destroyed by the blue laser light of HD-DVDs. Can be reliably avoided.
In the present embodiment, an example of discriminating the type of the disc loaded in the optical disc apparatus 400 has been shown. However, when one disc has a plurality of information surfaces with different recording densities and corresponding laser wavelengths, You may make it discriminate | determine whether it is a disc with the kind of information surface.

In this embodiment, the front light monitor is provided for each laser wavelength. However, the front light monitor may be provided to irradiate the laser at a low output.
Further, in this embodiment, the low NA objective in which the focal point of the infrared laser beam is focused on the side farther in the normal direction (the optical axis direction of the objective lens 33) than the focal point of the red laser beam. Although the example using the lens 33 has been shown, the focal point of the infrared laser light is focused closer to the side closer to the normal direction (the optical axis direction of the objective lens) than the focal point of the red laser light. The low NA objective lens 33 may be used to move the position of the low NA objective lens 33 during the disc discrimination operation in a direction away from the vicinity of the surface of the optical disc 1.
In addition, when laser light emission is performed with a recording light emission drive signal at the time of disc discrimination, a high frequency may be superimposed on the recording light emission drive signal.

In this embodiment, the laser light source to be controlled by the reproduction light emission drive signal and the recording light emission drive signal at the time of disc discrimination is fixed, but may be freely selected.
(4.2.2: Disc discriminating operation (in the case of BD))
Next, with reference to FIG. 16, an operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 400 is a BD will be described.
The BD has an information surface at a position of about 0.1 mm from the surface of the optical disc 1 (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33).
In FIG. 16, the blue laser light is emitted from the high NA objective lens 32 to the BD, and at the same time the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. The high NA objective lens position and the focus error signal when the low NA objective lens 33 is driven are shown.

FIG. 16 (1) is a diagram showing the relationship between time and the position of the high NA objective lens 32, where the horizontal axis is time and the vertical axis is the position of the high NA objective lens 32. Specifically, FIG. 16A shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. 4 shows a position signal of the high NA objective lens 32 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other.
FIG. 16B is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 16B shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. When the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other, the servo signal generation circuit (servo signal generation unit) 57 generates a focus error signal (signal of FIG. 13) from the output of the infrared laser light detector 23. Corresponding to the signal transmitted by the line P1).

FIG. 16 (3) is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 16 (3) shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. A focus error signal (signal line in FIG. 13) generated by the servo signal generation circuit (servo signal generation unit) 57 from the output of the red laser light detector 24 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other. This corresponds to the signal transmitted by P2.).
FIG. 16 (4) is a diagram showing the relationship between time and the focus error signal level, where the horizontal axis is time and the vertical axis is the focus error signal level. Specifically, FIG. 16 (4) shows a BD in a state where blue laser light is emitted from the high NA objective lens 32 and red laser light and infrared laser light are emitted simultaneously from the low NA objective lens 33. A focus error signal (signal line in FIG. 13) generated by the servo signal generation circuit (servo signal generation unit) 57 from the output of the blue laser light detector 25 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other. This corresponds to the signal transmitted by P3).

FIG. 16 (6) is a diagram showing the relationship between time and the optical path switching signal level, as in FIG. 15 (6). The details are the same as described above, and a description thereof will be omitted.
At the disc discrimination start timing T50, the disc discrimination controller (disc discriminator) 52 starts disc discriminating operation. The subsequent operations up to the operation of raising the high NA objective lens and the low NA objective lens will be described above. Since it is the same as the operation | movement which performed, description is abbreviate | omitted.
At timing T51, the focal point of the infrared laser light passes through the surface of the BD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and is focused based on the signal from the infrared laser light detector 23 when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W161 in FIG. 16 is output in the vicinity of timing T51.

  As shown in FIG. 14A, the focal point of the infrared laser beam is farther in the normal direction (the optical axis direction of the low NA objective lens 33) than the focal point of the red laser beam. Is used, and the focus of the red laser light focused by the low NA objective lens 33 is set to the objective lenses 32 and 33 from the focus of the blue laser light converged by the high NA objective lens 32. In order to set a driving offset value in the driving difference adding unit 58 so as to focus on the far side in the normal direction (the optical axis direction of each of the objective lenses 32 and 33), the focus of the red laser beam is BD at timing T52. A focus error signal is obtained based on a signal from the detector 24 for red laser light when passing through the surface (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33). It is. That is, a focus error signal having a waveform as indicated by W163 in FIG. 16 is output in the vicinity of timing T52.

At the timing T53, the focal point of the blue laser light passes through the surface of the BD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and is focused based on the signal from the detector 25 for blue laser light when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W165 in FIG. 16 is output in the vicinity of timing T53. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L9, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
At timing T54, the focal point of the infrared laser light passes through the information surface of the BD, and a focus error signal is obtained based on the signal from the infrared laser light detector 23 at the time of passage. That is, a focus error signal having a waveform as indicated by W162 in FIG. 16 is output in the vicinity of timing T54. Since the amplitude of the focus error signal obtained at this time does not exceed the certain level L7, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.

Next, at timing T55, the focal point of the red laser light passes through the information surface of the BD, and a focus error signal is obtained based on the signal from the red laser light detector 24 when passing. That is, a focus error signal having a waveform as indicated by W164 in FIG. 16 is output in the vicinity of timing T55. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L8, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
At timing T56, the focal point of the blue laser light passes through the information surface of the BD, and a focus error signal is obtained based on the signal from the blue laser light detector 25 when passing. That is, a focus error signal having a waveform as indicated by W167 in FIG. 16 is output in the vicinity of timing T56. Since the amplitude of the focus error signal obtained at this time exceeds a certain level L9, the disc discrimination controller (disc discriminator) 52 determines that the loaded disc is a BD.

As described above, the optical disc apparatus 400 can quickly determine that the loaded disc is a BD while reliably avoiding the destruction of the recorded information on the DVD information surface by the blue laser light.
[Fifth Embodiment]
A fifth embodiment will be described with reference to FIGS.
<5.1 Configuration of Optical Disc Device>
FIG. 17 is a block diagram showing the configuration of the optical disc apparatus 400 ′ according to this embodiment.
The optical disc apparatus 400 ′ according to the present embodiment is different from the optical disc apparatus 400 according to the fourth embodiment in the following points.
The first difference is that the infrared laser light detector 23, the red laser light detector 24, and the blue laser light detector 26 in the optical disc apparatus 400 are replaced with a multiplexed laser light detector 261.

Second, the servo signal generation unit 57 in the optical disc apparatus 400 is replaced with a servo signal generation unit 57 ′.
Third, the drive difference adding unit 58 in the optical disc apparatus 400 is deleted, and a drive difference adding unit 58 ′ is added at the position shown in FIG.
In other respects, the optical disc apparatus 400 ′ is the same as the optical disc apparatus 400, and thus the description thereof is omitted.
When the optical path switch 39 is in the ON state, the multiple laser light detector 261 is irradiated from the infrared laser light source 11 and reflected from the optical disk 1 and the red laser light source 12 and reflected from the optical disk 1. The irradiated red laser light is irradiated. Then, the multiple laser beam detector 261 outputs an output signal corresponding to the intensity of the irradiated infrared laser beam and red laser beam to the servo signal generator 57 ′.

The multiple laser light detector 261 is irradiated with the blue laser light emitted from the blue laser light source 17 and reflected by the optical disc 1 when the optical path switch 39 is OFF. Then, the multiple laser light detector 261 outputs an output signal corresponding to the intensity of the emitted blue laser light to the servo signal generator 57 ′.
The servo signal generation unit 57 ′ generates a servo signal from outputs from the blue laser light detector 25 and the multiple laser light detector 261 and outputs the servo signal to the disk determination unit 52.
The drive difference adding unit 58 ′ offsets (adds) a signal at a predetermined level to the drive output (output of the drive signal) from the disc discrimination controller (disc discriminator) 52 and outputs it to the focus actuator 37 for high NA. To do.
In other words, in the optical disc apparatus 400 ′, the high NA objective lens 32 and the low NA objective lens 32 are maintained in a state in which the high NA objective lens 32 is disposed closer to the optical disc 1 than the low NA objective lens 33 by an offset amount. The drive control of the lens 33 is executed. This point is different from the optical disc apparatus 400.

The positional relationship between the high NA objective lens 32 and the low NA objective lens 33 may be opposite to the above, but when the laser light emitted from the high NA objective lens 32 is blue laser light, the power consumption Therefore, as described above, it is preferable to drive and control the high NA objective lens 32 by adding an offset value so as to be closer to the optical disc 1 because power consumption can be reduced.
<5.2: Operation of Optical Disc Device>
Since the basic operation of the optical disc apparatus 400 ′ is the same as that of the optical disc apparatus 400 of the fourth embodiment, different points will be described below.
(5.2.1: Disc discriminating operation (in the case of HD-DVD))
Next, with reference to FIG. 18, an operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 400 ′ is an HD-DVD will be described.

FIG. 18 shows a high NA objective in which blue laser light is emitted from the high NA objective lens 32 and red laser light and infrared laser light are simultaneously emitted from the low NA objective lens 33 for the HD-DVD. The high NA objective lens 32 and low NA objective lens position and focus error signal when the lens 32 and low NA objective lens 33 are driven, and then blue laser light is emitted from the low NA objective lens 33. The low NA objective lens position and the focus error signal when the NA objective lens 33 is driven are shown.
FIG. 18 (1) is a diagram showing the relationship between time and the position of the low NA objective lens 33, where the horizontal axis is time and the vertical axis is the position of the low NA objective lens 33. Specifically, FIG. 18A shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. The position signal of the low NA objective lens 33 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD is shown.

FIG. 18B is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 18B shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. A focus error signal generated by the servo signal generation circuit (servo signal generation unit) 57 ′ when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD from the output of the detector 261 for multiple laser beams (FIG. 17). Corresponding to the signal transmitted by the signal line P7.).
FIG. 18 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 18 (3) shows a state in which blue laser light is emitted from the high NA objective lens 32 and red laser light and infrared laser light are simultaneously emitted from the low NA objective lens 33. A focus error signal generated by the servo signal generation circuit (servo signal generation unit) 57 ′ when the high NA objective lens 32 and the low NA objective lens 33 are brought close to the DVD from the output of the blue laser light detector 25 (FIG. 17). Corresponding to the signal transmitted by the signal line P6.).

  FIG. 18 (4) is a diagram showing the relationship between time and the optical path switching signal level, with the horizontal axis representing time and the vertical axis representing the optical path switching signal level. Specifically, FIG. 18 (5) shows a state in which the high NA objective lens 32 emits blue laser light and the low NA objective lens 33 simultaneously emits red laser light and infrared laser light. Blue laser when the objective lens 32 and the low NA objective lens 33 are driven, and then the high NA objective lens 32 and the low NA objective lens 33 are driven in a state where blue laser light is emitted from the low NA objective lens 33. A state in which light is output from either the high NA objective lens 32 or the low NA objective lens 33 is shown. That is, in FIG. 18 (4), the blue laser light is output from the high NA objective lens 32 during the period from time T60 to T66, and the blue laser light is output from the low NA objective lens during the period after time T66. This indicates that the data is output from 33.

At the disc discrimination start timing T60, the disc discrimination controller (disc discriminator) 52 starts the disc discrimination operation. The subsequent operation up to the operation of irradiating the optical disc 1 with the laser light is the same as the operation described above, and thus the description thereof is omitted.
The disc discrimination controller (disc discriminator) 52 outputs drive signals for raising the positions of the high NA objective lens 32 and the low NA objective lens 33. The low NA focus actuator 38 raises the low NA objective lens 33 by the drive signal output from the disk discrimination controller (disk discrimination unit) 52 (the low NA objective lens 33 is brought close to the optical disc 1). The high NA focus actuator 37 is a high NA objective lens based on a drive signal obtained by adding a predetermined drive amount to the drive signal output from the disc discrimination controller (disc discrimination unit) 52 by the drive difference addition unit 58 ′. 32 is raised (the high NA objective lens 32 is brought close to the optical disc 1).

At timing T61, the focal point of the infrared laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and based on the signal from the multiple laser light detector 261 at the time of passage. A focus error signal is obtained. That is, a focus error signal having a waveform as indicated by W181 in FIG. 18 is output in the vicinity of timing T61.
A low NA objective lens 33 in which the focal point of the infrared laser beam is focused on the side farther in the normal direction (the optical axis direction of the low NA objective lens 33) than the focal point of the red laser beam. The focal point of the red laser beam used and converged by the low NA objective lens 33 is normal to the objective lenses 32 and 33 from the focal point of the blue laser beam converged by the high NA objective lens 32 (of the objective lenses 32 and 33). In order to set a drive offset value that focuses on the far side in the optical axis direction in the drive difference adding unit 58 ′, the red laser beam is focused on the surface of the HD-DVD (objective lenses 32 and 33 at timing T62). The focus error signal is obtained on the basis of the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W182 in FIG. 18 is output in the vicinity of timing T62.

At timing T63, the focal point of the blue laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and based on the signal from the detector 25 for blue laser light when passing. To obtain a focus error signal. That is, a focus error signal having a waveform as indicated by W185 in FIG. 18 is output in the vicinity of timing T63. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L8, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
At timing T64, the focal point of the infrared laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W183 in FIG. 18 is output in the vicinity of timing T64. Since the amplitude of the focus error signal obtained at this time does not exceed the certain level L7, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.

Next, at timing T65, the focal point of the red laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W184 in FIG. 18 is output in the vicinity of timing T65. Since the amplitude of the focus error signal obtained at this time does not exceed the certain level L7, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
The disc discrimination controller (disc discriminating unit) 52 continues to raise the high NA objective lens 32 and the low NA objective lens 33, so that the high NA objective lens 32 or the low NA objective lens 33 is set in advance at timing T66. The position limit is reached. For this reason, the disc discrimination controller (disc discriminating unit) 52 stops raising the high NA objective lens 32 and the low NA objective lens 33 (the driving operation for approaching the optical disc 1), and moves the high NA objective lens 32 and the low NA objective lens 33 to each other. Lower (drive away from the optical disc 1). Then, the positions of the high NA objective lens 32 and the low NA objective lens 33 are returned to the positions at the timing T60 in FIG.

Next, the disk discriminating controller (disk discriminating unit) 52 extinguishes the emitted red laser light and infrared laser light, and outputs the optical path switching signal, thereby turning off the optical path switch 39.
In other words, the disc discrimination controller (disc discriminator) 52 emits blue laser light from the high NA objective lens 32 and simultaneously emits red laser light and red from the low NA objective lens 33 when the objective lens position reaches the position limit. The state is switched from the state in which the external laser light is simultaneously emitted to the state in which the blue laser is emitted from the low NA objective lens 33.
In a state where blue laser light is emitted from the low NA objective lens 33, the disc discrimination controller (disc discrimination unit) 52 raises the high NA objective lens 32 and the low NA objective lens 33 again (closes to the optical disc 1).

At timing T67, the focal point of the blue laser light passes through the surface of the HD-DVD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and is focused based on the signal from the multiple laser light detector 261 when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W186 in FIG. 18 is output in the vicinity of timing T67.
At timing T68, the focal point of the blue laser light passes through the information surface of the HD-DVD, and a focus error signal is obtained based on the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W187 in FIG. 18 is output in the vicinity of timing T68. Since the amplitude of the focus error signal obtained at this time exceeds a certain level L10, the disc discrimination controller (disc discrimination unit) 52 determines that the loaded disc is an HD-DVD.

As described above, the optical disc apparatus 400 ′ can quickly determine that the loaded disc is an HD-DVD while reliably avoiding destruction of the recorded information on the DVD information surface by the blue laser light. it can.
(5.2.2: Disc discriminating operation (in the case of BD))
Next, with reference to FIG. 19, the operation of disc discrimination by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus 400 ′ is a BD will be described.
In FIG. 19, the blue laser light is emitted from the high NA objective lens 32 to the BD, and at the same time the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. The high NA objective lens position and the focus error signal when the low NA objective lens 33 is driven are shown.

FIG. 19 (1) is a diagram showing the relationship between time and the position of the high NA objective lens 32, where the horizontal axis is time and the vertical axis is the position of the high NA objective lens 32. Specifically, FIG. 19A shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. FIG. 6 shows a position signal of the low NA objective lens 33 when the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other.
FIG. 19B is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 19B shows a state in which the blue laser light is emitted from the high NA objective lens 32 and the red laser light and the infrared laser light are simultaneously emitted from the low NA objective lens 33. The servo error generation circuit (servo signal generation unit) 57 ′ when the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other generates a focus error signal (signal of FIG. 17) generated from the output of the detector 261 for multiple laser beams. Corresponding to the signal transmitted by the line P7).

FIG. 19 (3) is a diagram showing the relationship between time and the focus error signal level, with the horizontal axis representing time and the vertical axis representing the focus error signal level. Specifically, FIG. 19 (3) shows a BD in a state in which blue laser light is emitted from the high NA objective lens 32 and red laser light and infrared laser light are simultaneously emitted from the low NA objective lens 33. When the high NA objective lens 32 and the low NA objective lens 33 are brought close to each other, the servo signal generation circuit (servo signal generation unit) 57 ′ generates a focus error signal (signal of FIG. 17) from the output of the blue laser light detector 25. Corresponding to the signal transmitted by the line P6).
FIG. 19 (4) is a diagram showing the relationship between time and the optical path switching signal level, as in FIG. 18 (4). The details are the same as described above, and a description thereof will be omitted.
At the disc discrimination start timing T70, the disc discrimination controller (disc discriminator) 52 starts disc discriminating operation. The subsequent operations up to the operation of raising the high NA objective lens and the low NA objective lens are described in (5). Since the operation is the same as that described in 2.2.1), the description thereof is omitted.

At timing T71, the focal point of the infrared laser light passes through the surface of the BD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33), and is focused based on the signal from the infrared laser light detector 23 when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W191 in FIG. 19 is output in the vicinity of timing T71.
A low NA objective lens 33 in which the focal point of the infrared laser beam is focused on the side farther in the normal direction (the optical axis direction of the low NA objective lens 33) than the focal point of the red laser beam. The focal point of the red laser beam used and converged by the low NA objective lens 33 is normal to the objective lenses 32 and 33 from the focal point of the blue laser beam converged by the high NA objective lens 32 (of the objective lenses 32 and 33). In order to set a drive offset value that focuses on the far side in the optical axis direction in the drive difference adder 58 ′, the focus of the red laser beam faces the surface of the BD (the objective lenses 32 and 33 at timing T72). The focus error signal is obtained based on the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W192 in FIG. 19 is output in the vicinity of timing T72.

Further, at timing T73, the focal point of the blue laser light passes through the surface of the BD (the surface of the optical disc 1 on the side facing the objective lenses 32 and 33) and is focused based on the signal from the detector 25 for blue laser light when passing. An error signal is obtained. That is, a focus error signal having a waveform as indicated by W195 in FIG. 19 is output in the vicinity of timing T73. Since the amplitude of the focus error signal obtained at this time does not exceed a certain level L8, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
At timing T74, the focal point of the infrared laser light passes through the information surface of the BD, and a focus error signal is obtained based on the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W193 in FIG. 19 is output in the vicinity of timing T74. Since the amplitude of the focus error signal obtained at this time does not exceed the certain level L7, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.

Next, at timing T75, the focal point of the red laser light passes through the information surface of the BD, and a focus error signal is obtained based on the signal from the multiple laser light detector 261 at the time of passage. That is, a focus error signal having a waveform as indicated by W194 in FIG. 19 is output in the vicinity of timing T75. Since the amplitude of the focus error signal obtained at this time does not exceed the certain level L7, the disc discrimination controller (disc discriminator) 52 continues the disc discrimination operation.
At timing T76, the focal point of the blue laser light passes through the information surface of the BD, and a focus error signal is obtained based on the signal from the blue laser light detector 25 when passing. That is, a focus error signal having a waveform as indicated by W196 in FIG. 19 is output in the vicinity of timing T76. Since the amplitude of the focus error signal obtained at this time exceeds a certain level L8, the disc discrimination controller (disc discrimination unit) 52 determines that the loaded disc is a BD.

As described above, the optical disc apparatus 400 ′ can quickly determine that the loaded disc is a BD while reliably avoiding the destruction of the recorded information on the DVD information surface by the blue laser light.
[Other Embodiments]
(1)
The drive control of the low NA objective lens 33 and the high NA objective lens 32 in the fourth and fifth embodiments may be as shown in FIG. This will be described with reference to FIG.
In the optical disc apparatus 400 (or optical disc apparatus 400 ′), the default value of the low NA objective lens 33 is set at the position of LEV0 shown in FIG. 20A (at the same time, the default value of the high NA objective lens 32 is offset from LEV0. When the optical path switch 39 is in the ON state, the low NA objective lens 33 is set so that the low NA objective lens 33 is at the LEVH position in FIG. Then, the high NA objective lens 32 is moved, laser light irradiation is started from this state, and drive control of the low NA objective lens 33 and the high NA objective lens 32 is performed. When the optical path switch 39 is in the OFF state, the non-driven high NA objective lens 32 is moved to the default value of the high NA objective lens 32 and driven as shown in FIG. 20B. Is moved to the position of LEVL in FIG. 20B, and laser light irradiation is started from that position, and drive control of the low NA objective lens 33 is performed.

In the optical disk device 400 (or the optical disk device 400 ′), the power consumption of the high NA focus actuator 37 when the blue laser is emitted from the high NA objective lens 32 can be reduced by controlling in this way. The power consumption in the optical disc apparatus 400 (or the optical disc apparatus 400 ′) can be reduced.
In the fourth and fifth embodiments, the high NA focus actuator 37 and the low NA focus actuator 38 are separately provided, and the high NA objective lens 32 and the low NA objective lens 33 are driven and controlled independently. However, the present invention is not limited to this. For example, the high NA objective lens 32 and the low NA objective lens 33 are fixedly arranged by being shifted by an offset value, and a single actuator is used to The NA objective lens 32 and the low NA objective lens 33 may be driven and controlled. In this case, the drive difference adder 58 (drive difference adder 58 ′) can be omitted.

(2)
In the above embodiment, a case has been described in which the disc loaded in the optical disc apparatus is discriminated by comparing the amplitude of the focus error signal with a predetermined level. However, the present invention is not limited to this. The disc discrimination operation may be performed using a signal obtained by reproducing information on the disc instead of the error signal.
The comparison of the predetermined level of the focus error signal may be a comparison between the peak-peak value of the focus error signal and the predetermined level, or a comparison between the amplitude value of the focus error signal and the predetermined level. May be.
Further, since the reflectivity (for example, disc type such as CD, DVD, DVD-ROM, DVD-RAM, etc.) differs depending on the disc type, a predetermined level for comparison with the focus error signal depends on the reflectivity of the disc. May be changed.

In addition, the normalized focus error signal (for example, the focus error signal value is an AS signal) obtained by normalizing the focus error signal with an AS (All Sum) signal (a total light amount sum signal output from the laser beam detector). The signal obtained by dividing by the value may be compared with a predetermined level. By doing so, in the optical disc apparatus, it is possible to absorb an individual difference of loaded discs and execute an accurate detection operation.
(3)
In the optical disk device described in the above embodiment, each block may be individually made into one chip by a semiconductor device such as an LSI, or may be made into one chip so as to include a part or the whole.
Here, although LSI is used, it may be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.
Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. There is a possibility of adaptation of biotechnology.
Moreover, each process of the said embodiment may be implement | achieved by hardware, and may be implement | achieved by software. Further, it may be realized by mixed processing of software and hardware.

  The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the invention.

  An optical disc apparatus, an optical disc discriminating method, a program, and an integrated circuit according to the present invention execute discriminating discs of a plurality of standards safely and in a short time without destroying recorded information on a loaded disc. Therefore, the present invention is useful in the optical disc related industry field, and the optical disc apparatus, the optical disc discrimination method, the program, and the integrated circuit according to the present invention can be implemented in this field.

1 is a block diagram showing the configuration of an optical disc device according to a first embodiment. Schematic diagram for explaining a disc discrimination operation by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the first embodiment is a CD and a DVD. Timing chart for explaining disc discrimination operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the first embodiment is a CD Timing chart for explaining disc discrimination operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the first embodiment is a DVD A block diagram showing a configuration of an optical disc device according to a second embodiment. Schematic diagram for explaining the disc discriminating operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the second embodiment is a DVD or HD-DVD. Timing chart for explaining disc discriminating operation by simultaneous light emission of a plurality of lasers when a disc loaded in an optical disc apparatus according to the second embodiment is a DVD Timing chart for explaining disc discrimination operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the second embodiment is an HD-DVD A block diagram showing a configuration of an optical disc apparatus according to a third embodiment. Schematic diagram for explaining a disc discrimination operation by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the third embodiment is a DVD or an HD-DVD. Timing chart for explaining disc discriminating operation by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the third embodiment is a DVD Timing chart for explaining disc discrimination operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the third embodiment is an HD-DVD A block diagram showing a configuration of an optical disc device according to a fourth embodiment. Schematic diagram for explaining a disc discrimination operation by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the fourth embodiment is an HD-DVD. Timing chart for explaining disc discrimination operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the fourth embodiment is an HD-DVD Timing chart for explaining disc discriminating operation by simultaneous emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the fourth embodiment is a BD A block diagram showing a configuration of an optical disc device according to a fifth embodiment. Timing chart for explaining disc discriminating operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the fifth embodiment is an HD-DVD Timing chart for explaining disc discriminating operation by simultaneous light emission of a plurality of lasers when the disc loaded in the optical disc apparatus according to the fifth embodiment is a BD Explanatory drawing of drive control of the low NA objective lens 33 and the high NA objective lens 32 of the optical disk apparatus which concerns on other embodiment. Block diagram showing the configuration of a conventional optical disc apparatus Timing chart for explaining disc discriminating operation when a disc loaded in a conventional optical disc apparatus is a CD Timing chart for explaining disc discriminating operation when a disc loaded in a conventional optical disc apparatus is a DVD

Explanation of symbols

100, 200, 300, 400, 400 ′, 900 Optical disk device 1 Optical disk 10, 2010, 3010, 4010, 1610 Optical head 11 Infrared laser light source 12 Red laser light source 13 Infrared laser beam splitter 14 Red laser beam splitter 15 Infrared laser front light monitor 16 Red laser front light monitor 17 Blue laser light source 18 Blue laser beam splitter 19 Blue laser front light monitor 20 Irradiation beam splitter 21 Detector beam splitter 22 Detector beam splitter 23 Infrared laser Detector for light 24 Detector for red laser light 25 Detector for blue laser light 26 Detector for blue laser light 261 Detector for multiple laser light 27 Beam splitter for red laser irradiation 28 Blue laser illumination Beam splitter 29 Objective lens 30 Objective lens for red laser 31 Objective lens for blue laser 32 High NA objective lens 33 Low NA objective lens 34 Focus actuator 35 Focus actuator for blue laser 36 Focus actuator for red laser 37 Focus actuator for high NA 38 Focus actuator for low NA 39 Optical path switcher 40 LDD
41 Light emitting laser selection SW
42 Playback light emission drive signal gain 43 Recording light emission drive signal switching SW
44 Simultaneous emission gain 45 Recording light emission drive signal gain 46 Recording light emission drive signal switching SW
47 Gain for simultaneous light emission 48 Recording light emission drive signal gain 50 Disc discriminator controller (disc discriminator)
51 Disc discriminator controller (disc discriminator)
52 Disc discriminator controller (disc discriminator)
53 Laser controller (Laser controller)
54 Laser controller (Laser controller)
55 Laser controller (laser controller)
56 Servo signal generation circuit (servo signal generator)
57, 57 'Servo signal generation circuit (servo signal generation unit)
58, 58 'Drive difference adder

Claims (25)

A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An objective lens for simultaneously irradiating the optical disk with the first laser light and the second laser light mixed by the laser light mixing and separating unit;
An objective lens driving section that varies the distance between the objective lens and the optical disc by driving the objective lens to the perspective of the optical disc;
A first laser beam detector that detects the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
A servo signal generator for generating a first laser light detection signal corresponding to the detection result of the first laser light detector and a second laser light detection signal corresponding to the detection result of the second laser light detector;
A disc discriminator for discriminating the type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal;
An optical disc device comprising: The objective lens has a focal length for the first laser light that is longer than a focal length for the second laser light, and the objective lens and the objective lens in an initial state when performing an operation of discriminating a disc type The optical disc is disposed at an initial position, which is a position where the distance from the surface of the optical disc facing the objective lens is longer than the focal length of the objective lens with respect to the first laser beam,
The objective lens driving unit drives the objective lens in a direction in which the distance between the objective lens and the optical disc decreases from the initial position,
The disc discriminating unit is configured to detect the first laser light detection signal and the disc in a period in which the objective lens is driven by the objective lens driving unit in a direction in which the distance between the objective lens and the optical disc decreases from the initial position. By comparing the signal level of the second laser light detection signal with a predetermined threshold value, the type of the optical disc is determined.
The optical disc apparatus according to claim 1. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
An objective lens for a first laser beam that irradiates the optical disc with the first laser beam;
A second laser beam objective lens for irradiating the optical disk with the second laser beam;
A first laser beam objective lens driving unit configured to vary a distance between the first laser beam objective lens and the optical disc by driving the first laser beam objective lens with respect to the optical disc;
A second laser light objective lens driving unit configured to vary a distance between the second laser light objective lens and the optical disk by driving the second laser light objective lens with respect to the optical disk;
A first laser beam detector that detects the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
A servo signal generator for generating a first laser light detection signal corresponding to the detection result of the first laser light detector and a second laser light detection signal corresponding to the detection result of the second laser light detector;
A second laser light objective lens drive control signal for driving the second laser light objective lens is output, and based on the first laser light detection signal and the second laser light detection signal, A disc discriminating unit for discriminating the type;
A drive difference adder for generating a first laser light objective lens drive control signal for driving the first laser light objective lens by adding an offset value to the second laser light objective lens drive control signal; ,
With
The first laser light objective lens driving unit drives the first laser light objective lens according to the first laser light objective lens drive control signal,
The second laser light objective lens driving unit drives the second laser light objective lens according to the second laser light objective lens drive control signal.
Optical disk device. The first laser light objective lens is located on an opposite side of the first laser light objective lens and the first laser light objective lens of the optical disk in an initial state when performing an operation of discriminating the type of the disk. It is arranged at the initial position for the first laser light objective lens, which is a position where the distance to the surface is longer than the focal length of the objective lens for the first laser light,
The first laser light objective lens driving unit is configured to reduce the distance between the first laser light objective lens and the optical disk from the initial position for the first laser light objective lens. Drive in the direction
The second laser light objective lens driving unit is configured to move the second laser light objective lens to the second position when the first laser light objective lens is positioned at an initial position for the first laser light objective lens. The first laser light objective lens in a direction in which the distance between the second laser light objective lens and the optical disk decreases from an initial position for the second laser light objective lens, which is a position where the laser light objective lens exists. The drive unit is driven at the same speed as that for driving the first laser beam objective lens;
The disc discriminating unit is configured such that the first laser beam objective lens and the second laser beam objective lens are moved from the first laser beam objective lens driving unit and the second laser beam objective lens driving unit to the first laser beam objective lens driving unit. The first laser light detection signal and the second laser light are driven in a direction in which the distance from the optical disk from the initial position for the light objective lens and the initial position for the second laser light objective lens is reduced. By comparing the signal level of the detection signal with a predetermined threshold value, the type of the optical disc is determined.
The optical disc apparatus according to claim 3. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
A high NA objective lens having a higher aperture ratio than the low NA objective lens;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens;
A low NA objective lens driving unit that varies the distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the perspective of the optical disc;
A high NA objective lens driving unit configured to vary a distance between the high NA objective lens and the optical disc by driving the high NA objective lens with respect to the optical disc;
A first laser beam detector that detects the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
A third laser beam detector for detecting the intensity of the third laser beam reflected from the optical disc;
A first laser light detection signal corresponding to a detection result of the first laser light detection unit, a second laser light detection signal corresponding to a detection result of the second laser light detection unit, and the third laser light detection unit; A servo signal generator for generating a third laser light detection signal corresponding to the detection result at
Outputting a high NA objective lens drive control signal for driving the high NA objective lens, and based on the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal, A disc discriminator for discriminating the type of optical disc;
A drive difference adding unit that generates a low NA objective lens drive control signal for driving the low NA objective lens by adding an offset value to the high NA objective lens drive control signal;
With
The high NA objective lens irradiates the optical disc with the third laser light when the optical path switching unit is in an ON state,
The low NA objective lens driving unit drives the low NA objective lens according to the low NA objective lens drive control signal,
The high NA objective lens driving unit drives the high NA objective lens according to the high NA objective lens drive control signal.
Optical disk device. In the initial state when the low NA objective lens performs an operation for discriminating the type of the disk, the distance between the low NA objective lens and the surface of the optical disk facing the low NA objective lens is the first laser. It is arranged at the initial position for the low NA objective lens, which is a position that is longer than the focal length of the low NA objective lens for light,
The low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance between the low NA objective lens and the optical disc decreases from the initial position,
The high NA objective lens driving unit is a position where the high NA objective lens is located when the high NA objective lens is located at the initial position for the low NA objective lens. The low NA objective lens drive unit is driven at the same speed as the low NA objective lens is driven in the direction in which the distance between the high NA objective lens and the optical disk is reduced from the initial position for use;
The disk discriminating unit is configured so that the low NA objective lens and the high NA objective lens are moved to the low NA objective lens initial position and the high NA objective lens initial position by the low NA objective lens driving unit and the high NA objective lens driving unit. During a period in which the distance from the optical disc is decreased, the first laser beam detection signal, the second laser beam detection signal, and the third laser beam detection signal are set at predetermined threshold levels. The type of the optical disc is determined by comparing with the value.
The optical disk device according to claim 5. In the first stage, the drive control unit receives the first laser light from the first laser light source, the second laser light from the second laser light source, and the third laser light from the third laser light source. Drive control to irradiate each, and drive control to irradiate only the third laser light from the third laser light source in the second stage,
The optical path switching unit is in an ON state in the first stage, and is in an OFF state in the second stage.
In the first stage, the high NA objective lens driving unit drives the high NA objective lens in a direction in which the distance between the high NA objective lens and the optical disc decreases from the initial position for the high NA objective lens, In the second stage, without driving the high NA objective lens,
In the first stage, the low NA objective lens driving unit moves the high NA objective lens in a direction in which the distance between the low NA objective lens and the optical disc decreases from the initial position for the low NA objective lens. The NA objective lens driving unit is driven at the same speed as that for driving the high NA objective lens. In the second stage, the low NA objective lens is moved from the initial position for the low NA objective lens to the low NA objective lens. Drive in a direction where the distance from the optical disk decreases,
The disc discriminating unit discriminates the type of the optical disc in the first stage based on the first laser beam detection signal, the second laser beam detection signal, and the third laser beam detection signal, and the second stage. And determining the type of the optical disk based on the third laser light detection signal.
The optical disc apparatus according to claim 5 or 6. In the first stage, the disk discriminating unit causes the low NA objective lens driving unit and the high NA objective lens driving unit to move the low NA objective lens and the high NA objective lens to the initial position for the low NA objective lens and the low NA objective lens. Signals of the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal in a period in which the distance from the optical disk is decreased in the direction of decreasing the distance from the initial position for the high NA objective lens By comparing the level with a predetermined threshold, the type of the optical disc is determined,
In the second stage, during the period in which the low NA objective lens is driven by the low NA objective lens drive unit in a direction in which the distance from the initial position for the low NA objective lens is reduced, the third laser By comparing the signal level of the light detection signal with a predetermined threshold, the type of the optical disc is determined.
The optical disc apparatus according to claim 7. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
When the optical path switching unit is in an ON state, the optical disk is irradiated with the third laser light, and a high NA objective lens having a higher aperture ratio than the low NA objective lens;
A low NA objective lens driving unit that varies the distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the perspective of the optical disc;
A high NA objective lens driving unit configured to vary a distance between the high NA objective lens and the optical disc by driving the high NA objective lens with respect to the optical disc;
A multiple laser beam detector for detecting the intensity of the first laser beam and the intensity of the second laser beam reflected from the optical disc;
A third laser beam detector for detecting the intensity of the third laser beam reflected from the optical disc;
A servo signal generation unit for generating a multiple laser light detection signal corresponding to the detection result in the multiple laser light detection unit, and a third laser light detection signal corresponding to the detection result in the third laser light detection unit;
A disc discrimination unit that outputs a low NA objective lens drive control signal for driving the low NA objective lens and discriminates the type of the optical disc based on the multiplexed laser beam detection signal and the third laser beam detection signal When,
A drive difference adding unit that generates a high NA objective lens drive control signal for driving the high NA objective lens by adding an offset value to the low NA objective lens drive control signal;
With
The low NA objective lens driving unit drives the low NA objective lens according to the low NA objective lens drive control signal,
The high NA objective lens driving unit drives the high NA objective lens according to the high NA objective lens drive control signal.
Optical disk device. The low NA objective lens is an initial state in the case of performing an operation of discriminating the type of the disc, and the low NA objective lens and a surface of the first disc which is a surface of the optical disc facing the low NA objective lens. A low position where the distance is longer than the focal length of the low NA objective lens with respect to the first laser light, and is a position away from the first disk surface by a distance LEN0 toward the low NA objective lens side. It is placed at the initial position for NA objective lens,
In the initial state when the high NA objective lens performs an operation for discriminating the type of the disc, (the distance LEN0) − (the offset value Offset) (Offset> 0) from the first disc surface.
Is located at the initial position for high NA objective lens,
The low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance between the low NA objective lens and the optical disc decreases from the initial position for the low NA objective lens,
The high NA objective lens driving unit moves the high NA objective lens in a direction in which the distance between the high NA objective lens and the optical disc decreases from the initial position for the high NA objective lens. Driving at the same speed as driving the low NA objective lens,
The disk discriminating unit is configured so that the low NA objective lens and the high NA objective lens are moved to the low NA objective lens initial position and the high NA objective lens initial position by the low NA objective lens driving unit and the high NA objective lens driving unit. By comparing the signal levels of the multiple laser light detection signal and the third laser light detection signal with a predetermined threshold value during a period in which the distance from the optical disk is driven in a direction in which the distance from the optical disk becomes small, the optical disk To determine the type of
The optical disk device according to claim 9. In the initial state, the high NA objective lens sets the distance between the focal position of the low NA objective lens and the first disk surface for the first laser light to LEN1, and the low NA objective for the second laser light. When the distance between the focal position of the objective lens and the first disk surface is LEN2, and the distance between the focal position of the high NA objective lens and the first disk surface for the third laser light is LEN3,
LEN1>LEN2> LEN3
From the first disk surface, the offset value Offset determined to be (the distance LEN0) − (the offset value Offset) (Offset> 0)
Arranged at the initial position for the high NA objective lens, which is a position separated by
The optical disk device according to claim 10. In the first stage, the drive control unit receives the first laser light from the first laser light source, the second laser light from the second laser light source, and the third laser light from the third laser light source. Drive control to irradiate each, and in the second stage, drive control to irradiate only the third laser light from the third laser light source,
The optical path switching unit is in an ON state in the first stage, and is in an OFF state in the second stage.
In the first stage, the low NA objective lens driving unit drives the low NA objective lens in a direction in which the distance between the low NA objective lens and the optical disc decreases from the initial position for the low NA objective lens, In the second stage, the low NA objective lens is driven in a direction in which the distance between the low NA objective lens and the optical disc decreases from the initial position for the low NA objective lens,
In the first stage, the high NA objective lens driving unit moves the high NA objective lens in a direction in which the distance between the high NA objective lens and the optical disc decreases from the initial position for the high NA objective lens. The NA objective lens driving unit is driven at the same speed as that for driving the low NA objective lens, and in the second stage, the high NA objective lens is not driven,
The disc discriminating unit discriminates the type of the optical disc based on the multiplexed laser beam detection signal and the third laser beam detection signal in the first stage, and the third laser beam detection signal in the second stage. To determine the type of the optical disk,
The optical disc device according to claim 9. In the first stage, the disk discriminating unit causes the low NA objective lens driving unit and the high NA objective lens driving unit to move the low NA objective lens and the high NA objective lens to the initial position for the low NA objective lens and the low NA objective lens. The signal levels of the multiple laser light detection signal and the third laser light detection signal are compared with a predetermined threshold value during a period in which the distance from the optical disk is decreased from the initial position for the high NA objective lens. To determine the type of the optical disc,
In the second stage, during the period in which the low NA objective lens is driven by the low NA objective lens driving unit in a direction in which the distance from the initial position for the low NA objective lens becomes smaller, the multiple laser light By comparing the signal level of the detection signal with a predetermined threshold value, the type of the optical disc is determined.
The optical disc apparatus according to claim 12. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An optical disc discrimination method used in an optical disc apparatus comprising: an objective lens that simultaneously irradiates an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
An objective lens driving step of varying a distance between the objective lens and the optical disc by driving the objective lens to the perspective with respect to the optical disc;
A first laser beam detecting step for detecting an intensity of the first laser beam reflected from the optical disc;
A second laser beam detecting step for detecting the intensity of the second laser beam reflected from the optical disc;
A servo signal generation step for generating a first laser light detection signal corresponding to the detection result in the first laser light detection step and a second laser light detection signal corresponding to the detection result in the second laser light detection step;
A disc discriminating step for discriminating the type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal;
An optical disc discrimination method comprising: A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
An objective lens for a first laser beam that irradiates the optical disc with the first laser beam;
An optical disc discrimination method used in an optical disc apparatus comprising: a second laser beam objective lens that irradiates the optical disc with the second laser beam,
A first laser beam objective lens driving step of varying a distance between the first laser beam objective lens and the optical disc by driving the first laser beam objective lens with respect to the optical disc;
A second laser beam objective lens driving step for varying the distance between the second laser beam objective lens and the optical disc by driving the second laser beam objective lens to the perspective of the optical disc;
A first laser beam detecting step for detecting an intensity of the first laser beam reflected from the optical disc;
A second laser beam detecting step for detecting the intensity of the second laser beam reflected from the optical disc;
A servo signal generation step for generating a first laser light detection signal corresponding to the detection result in the first laser light detection step and a second laser light detection signal corresponding to the detection result in the second laser light detection step;
A second laser light objective lens drive control signal for driving the second laser light objective lens is output, and based on the first laser light detection signal and the second laser light detection signal, Disc discriminating step for discriminating the type;
A drive difference adding step for generating a first laser light objective lens drive control signal for driving the first laser light objective lens by adding an offset value to the second laser light objective lens drive control signal; ,
With
In the first laser light objective lens driving step, the first laser light objective lens is driven by the first laser light objective lens drive control signal,
In the second laser light objective lens driving step, the second laser light objective lens is driven by the second laser light objective lens drive control signal.
Optical disc identification method. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
A high NA objective lens having a higher aperture ratio than the low NA objective lens;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens; An optical disc discrimination method used for an optical disc apparatus comprising:
A low NA objective lens driving step of varying a distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the optical disc;
A high NA objective lens driving step of varying a distance between the high NA objective lens and the optical disc by driving the high NA objective lens to the perspective with respect to the optical disc;
A first laser beam detecting step for detecting an intensity of the first laser beam reflected from the optical disc;
A second laser beam detecting step for detecting the intensity of the second laser beam reflected from the optical disc;
A third laser beam detecting step for detecting the intensity of the third laser beam reflected from the optical disc;
A first laser light detection signal corresponding to a detection result in the first laser light detection step, a second laser light detection signal corresponding to a detection result in the second laser light detection step, and the third laser light detection step A servo signal generation step of generating a third laser light detection signal corresponding to the detection result at
Outputting a high NA objective lens drive control signal for driving the high NA objective lens, and based on the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal, Disc discriminating step for discriminating the type of optical disc;
A drive difference addition step of generating a low NA objective lens drive control signal for driving the low NA objective lens by adding an offset value to the high NA objective lens drive control signal;
With
In the low NA objective lens driving step, the low NA objective lens is driven by the low NA objective lens drive control signal,
In the high NA objective lens driving step, the high NA objective lens is driven by the high NA objective lens drive control signal.
Optical disc identification method. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
When the optical path switching unit is in the ON state, the optical disc discrimination used in the optical disc device is provided that includes irradiating the optical disc with the third laser light and a high NA objective lens having a higher aperture ratio than the low NA objective lens. A method,
A low NA objective lens driving step of varying a distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the optical disc;
A high NA objective lens driving step of varying a distance between the high NA objective lens and the optical disc by driving the high NA objective lens to the perspective with respect to the optical disc;
A multiple laser beam detection step for detecting the intensity of the first laser beam and the intensity of the second laser beam reflected from the optical disc;
A third laser beam detecting step for detecting the intensity of the third laser beam reflected from the optical disc;
A servo signal generation step for generating a multiple laser light detection signal corresponding to the detection result in the multiple laser light detection step, and a third laser light detection signal corresponding to the detection result in the third laser light detection step;
Disc discriminating step for outputting a low NA objective lens drive control signal for driving the low NA objective lens and discriminating the type of the optical disc based on the multiplexed laser light detection signal and the third laser light detection signal When,
A drive difference addition step of generating a high NA objective lens drive control signal for driving the high NA objective lens by adding an offset value to the low NA objective lens drive control signal;
With
In the low NA objective lens driving step, the low NA objective lens is driven by the low NA objective lens drive control signal,
In the high NA objective lens driving step, the high NA objective lens is driven by the high NA objective lens drive control signal.
Optical disc identification method. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An objective lens that irradiates an optical disk with the first laser light and the second laser light mixed by the laser light mixing / separating unit at the same time.
Computer
An objective lens driving unit that varies the distance between the objective lens and the optical disk by driving the objective lens to the perspective of the optical disk;
A first laser beam detector for detecting the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
A servo signal generator for generating a first laser light detection signal corresponding to the detection result of the first laser light detector and a second laser light detection signal corresponding to the detection result of the second laser light detector;
A disc discriminating unit for discriminating the type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal;
Program to function as. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
An objective lens for a first laser beam that irradiates the optical disc with the first laser beam;
A program used for an optical disc device comprising: a second laser beam objective lens that irradiates the optical disc with the second laser beam,
Computer
A first laser beam objective lens driving unit configured to vary a distance between the first laser beam objective lens and the optical disc by driving the first laser beam objective lens with respect to the optical disc;
A second laser beam objective lens driving unit configured to vary a distance between the second laser beam objective lens and the optical disc by driving the second laser beam objective lens with respect to the optical disc;
A first laser beam detector for detecting the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
A servo signal generator for generating a first laser light detection signal corresponding to the detection result of the first laser light detector and a second laser light detection signal corresponding to the detection result of the second laser light detector;
A second laser light objective lens drive control signal for driving the second laser light objective lens is output, and based on the first laser light detection signal and the second laser light detection signal, Disc discriminating unit for discriminating the type,
A drive difference adder for generating a first laser light objective lens drive control signal for driving the first laser light objective lens by adding an offset value to the second laser light objective lens drive control signal;
A program that functions as
The first laser light objective lens driving unit drives the first laser light objective lens according to the first laser light objective lens drive control signal,
The second laser light objective lens driving unit drives the second laser light objective lens according to the second laser light objective lens drive control signal.
program. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
A high NA objective lens having a higher aperture ratio than the low NA objective lens;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens; A program used in an optical disc device comprising:
Computer
A low NA objective lens driving unit that varies the distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the perspective of the optical disc;
A high-NA objective lens driving unit configured to vary a distance between the high-NA objective lens and the optical disc by driving the high-NA objective lens with respect to the optical disc;
A first laser beam detector for detecting the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
A third laser beam detector for detecting the intensity of the third laser beam reflected from the optical disc;
A first laser light detection signal corresponding to a detection result of the first laser light detection unit, a second laser light detection signal corresponding to a detection result of the second laser light detection unit, and the third laser light detection unit; A servo signal generator for generating a third laser light detection signal corresponding to the detection result at
Outputting a high NA objective lens drive control signal for driving the high NA objective lens, and based on the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal, A disc discriminator for discriminating the type of optical disc,
A drive difference adding unit that generates a low NA objective lens drive control signal for driving the low NA objective lens by adding an offset value to the high NA objective lens drive control signal;
Is a program for functioning as
The low NA objective lens driving unit drives the low NA objective lens according to the low NA objective lens drive control signal,
The high NA objective lens driving unit drives the high NA objective lens according to the high NA objective lens drive control signal.
program. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
When the optical path switching unit is in an ON state, the program is used in an optical disc device that irradiates the optical disc with the third laser light and includes a high NA objective lens having a higher aperture ratio than the low NA objective lens. There,
Computer
A low NA objective lens driving unit that varies the distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the perspective of the optical disc;
A high-NA objective lens driving unit configured to vary a distance between the high-NA objective lens and the optical disc by driving the high-NA objective lens with respect to the optical disc;
A multiple laser beam detector for detecting the intensity of the first laser beam and the intensity of the second laser beam reflected from the optical disc;
A third laser beam detector for detecting the intensity of the third laser beam reflected from the optical disc;
A servo signal generator for generating a multiple laser light detection signal corresponding to the detection result in the multiple laser light detector, and a third laser light detection signal corresponding to the detection result in the third laser light detector;
A disc discrimination unit that outputs a low NA objective lens drive control signal for driving the low NA objective lens and discriminates the type of the optical disc based on the multiplexed laser beam detection signal and the third laser beam detection signal ,
A drive difference adding unit that generates a high NA objective lens drive control signal for driving the high NA objective lens by adding an offset value to the low NA objective lens drive control signal;
Is a program for functioning as
The low NA objective lens driving unit drives the low NA objective lens according to the low NA objective lens drive control signal,
The high NA objective lens driving unit drives the high NA objective lens according to the high NA objective lens drive control signal.
program. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An objective lens for simultaneously irradiating the optical disk with the first laser light and the second laser light mixed by the laser light mixing and separating unit;
An objective lens driving section that varies the distance between the objective lens and the optical disc by driving the objective lens to the perspective of the optical disc;
A first laser beam detector that detects the intensity of the first laser beam reflected from the optical disc;
An integrated circuit used in an optical disc device comprising: a second laser beam detector that detects an intensity of the second laser beam reflected from the optical disc;
A servo signal generator for generating a first laser light detection signal corresponding to the detection result of the first laser light detector and a second laser light detection signal corresponding to the detection result of the second laser light detector;
A disc discriminator for discriminating the type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal;
An integrated circuit comprising: A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
An objective lens for a first laser beam that irradiates the optical disc with the first laser beam;
A second laser beam objective lens for irradiating the optical disk with the second laser beam;
A first laser beam objective lens driving unit configured to vary a distance between the first laser beam objective lens and the optical disc by driving the first laser beam objective lens with respect to the optical disc;
A second laser light objective lens driving unit configured to vary a distance between the second laser light objective lens and the optical disk by driving the second laser light objective lens with respect to the optical disk;
A first laser beam detector that detects the intensity of the first laser beam reflected from the optical disc;
An integrated circuit used in an optical disc device comprising: a second laser beam detector that detects an intensity of the second laser beam reflected from the optical disc;
A servo signal generator for generating a first laser light detection signal corresponding to the detection result of the first laser light detector and a second laser light detection signal corresponding to the detection result of the second laser light detector;
A second laser light objective lens drive control signal for driving the second laser light objective lens is output, and based on the first laser light detection signal and the second laser light detection signal, A disc discriminating unit for discriminating the type;
A drive difference adder for generating a first laser light objective lens drive control signal for driving the first laser light objective lens by adding an offset value to the second laser light objective lens drive control signal; ,
With
The first laser light objective lens driving unit drives the first laser light objective lens according to the first laser light objective lens drive control signal,
The second laser light objective lens driving unit drives the second laser light objective lens according to the second laser light objective lens drive control signal.
Integrated circuit. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
A high NA objective lens having a higher aperture ratio than the low NA objective lens;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens;
A low NA objective lens driving unit that varies the distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the perspective of the optical disc;
A high NA objective lens driving unit configured to vary a distance between the high NA objective lens and the optical disc by driving the high NA objective lens with respect to the optical disc;
A first laser beam detector that detects the intensity of the first laser beam reflected from the optical disc;
A second laser beam detector for detecting the intensity of the second laser beam reflected from the optical disc;
An integrated circuit used in an optical disc device comprising: a third laser beam detector that detects an intensity of the third laser beam reflected from the optical disc;
A first laser light detection signal corresponding to a detection result of the first laser light detection unit, a second laser light detection signal corresponding to a detection result of the second laser light detection unit, and the third laser light detection unit; A servo signal generator for generating a third laser light detection signal corresponding to the detection result at
Outputting a high NA objective lens drive control signal for driving the high NA objective lens, and based on the first laser light detection signal, the second laser light detection signal, and the third laser light detection signal, A disc discriminator for discriminating the type of optical disc;
A drive difference adding unit that generates a low NA objective lens drive control signal for driving the low NA objective lens by adding an offset value to the high NA objective lens drive control signal;
With
The low NA objective lens driving unit drives the low NA objective lens according to the low NA objective lens drive control signal,
The high NA objective lens driving unit drives the high NA objective lens according to the high NA objective lens drive control signal.
Integrated circuit. A first laser light source for irradiating the first laser light;
A second laser light source for irradiating a second laser beam having a shorter wavelength than the first laser beam;
A third laser light source for irradiating a third laser beam having a shorter wavelength than the second laser beam;
A laser control unit that controls driving of the first laser light source, the second laser light source, and the third laser light source;
A laser beam mixing and separating unit for mixing and separating the first laser beam and the second laser beam;
An optical path switching unit for setting the third laser light to an optical path for guiding the third laser light to the high NA objective lens in an ON state, and an optical path for setting the third laser light to an optical path for guiding the third laser light to the low NA objective lens;
A low NA objective lens for simultaneously irradiating an optical disc with the first laser beam and the second laser beam mixed by the laser beam mixing and separating unit;
When the optical path switching unit is in an ON state, the optical disk is irradiated with the third laser light, and a high NA objective lens having a higher aperture ratio than the low NA objective lens;
A low NA objective lens driving unit that varies the distance between the low NA objective lens and the optical disc by driving the low NA objective lens to the perspective of the optical disc;
A high NA objective lens driving unit configured to vary a distance between the high NA objective lens and the optical disc by driving the high NA objective lens with respect to the optical disc;
A multiple laser beam detector for detecting the intensity of the first laser beam and the intensity of the second laser beam reflected from the optical disc;
An integrated circuit used in an optical disc device comprising: a third laser beam detector that detects an intensity of the third laser beam reflected from the optical disc;
A servo signal generation unit for generating a multiple laser light detection signal corresponding to the detection result in the multiple laser light detection unit, and a third laser light detection signal corresponding to the detection result in the third laser light detection unit;
A disc discrimination unit that outputs a low NA objective lens drive control signal for driving the low NA objective lens and discriminates the type of the optical disc based on the multiplexed laser beam detection signal and the third laser beam detection signal When,
A drive difference adding unit that generates a high NA objective lens drive control signal for driving the high NA objective lens by adding an offset value to the low NA objective lens drive control signal;
With
The low NA objective lens driving unit drives the low NA objective lens according to the low NA objective lens drive control signal,
The high NA objective lens driving unit drives the high NA objective lens according to the high NA objective lens drive control signal.
Integrated circuit.

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