JP2008112555A - Optical pickup, optical disk drive, optical information recording / reproducing apparatus, and tilt adjustment method - Google Patents

Abstract

Provided is a tilt correction processing method capable of reliably detecting and adjusting a tilt amount in a short time, and adopting the method to start recording or reproduction in a short time.
In order to record or reproduce a plurality of optical information media, a single or a plurality of light sources (3) and a single or a plurality of objective lenses for condensing light from the light sources onto the optical information media ( 4), an objective lens actuator (7, 12) that can control the tilt of the objective lens by controlling the objective lens (4) in a focus direction and a tracking direction, and the optical disc (180, 181, 182). An optical information medium discriminating unit (6) for discriminating the type of the optical disc when recording or reproducing information, and at least one type of the optical information medium, based on the result of the type discrimination of the optical information medium, the information object An optical pickup having an objective lens tilt setting section (8, 9, 17) for tilting the objective lens by a preset amount by a lens actuator.
[Selection] Figure 7

Description

  The present invention relates to an optical disc apparatus that records or reproduces information on an optical information medium typified by an optical disc, and in particular, has a single or a plurality of light sources, and records or records a plurality of types of optical information media using the light sources. The present invention relates to an optical pickup capable of reproducing, an optical disk drive, an optical information recording / reproducing apparatus, and a tilt adjusting method.

  In recent years, optical disk devices have been actively developed as means for recording and reproducing large amounts of data, and attempts have been made to achieve higher recording density.

  In addition to conventional CDs (compact discs) and DVDs (digital multipurpose discs), recently, with the increase in recording capacity of optical information media, digital information of about 25 GB for single-sided single layers and about 50 GB for double-sided single layers Blu-ray discs that can be recorded or reproduced, and HD-DVDs (High Definition DVDs) that can record or reproduce digital information of about 20 GB on a single-sided single layer and about 40 GB on a single-sided two-layer are in practical use.

  A problem in achieving such a high recording density is to compensate for signal quality against variations in optical disk media and optical disk devices, as well as improving S / N and interference between recording pits. This is especially true for defocus, off-track (deviation of the light spot from the track center), tangential tilt (tilt in the tangential direction of the recording track), and radial tilt, which are typified by variations in the positional relationship between the optical head and optical disk medium It has been pointed out as a characteristic change of the reproduction channel due to (tilt in the radial direction of the disk) or the like, and a device with a small increase in error rate due to these is required.

  Now, in an optical disc apparatus that records or reproduces information on a recording or reproducing layer formed on an optical disc that is an optical information medium, the tangential tilt and the radial tilt are caused by disc warpage or clamping error. When this occurs, coma aberration occurs in a focused spot on the information recording surface of the optical disc.

  Therefore, it is necessary to perform tilt adjustment and tilt control for detecting the amount of tilt and correcting coma aberration as means for reducing deterioration in recording or reproducing performance due to the tilt of the disk (disk tilt) with respect to the optical axis of the laser beam. .

  Techniques relating to this tilt adjustment and tilt control have already been proposed and put into practical use.

  Here, a conventional optimum radial tilt control method will be described with reference to FIG.

  FIG. 17 is a block diagram of radial tilt control of a conventional optical disc recording apparatus. In FIG. 17, 201 is an optical disk, 202 is a pickup module, 203 is a spindle motor, 204 is a focus drive coil, 205 is an objective lens, 206 is a reflected light receiving unit, 207 is a laser diode as a light source, and 208 is a reflected light calculation unit. 209, a reflected light A / D conversion unit, 210 a reflected light A / D conversion value comparison unit, 211 a radial tilt control unit, radial tilt control unit, and 212 a focus drive unit. A conventional process for searching for an optimal radial tilt in the radial tilt control block configured as described above will be described.

When the optical disk 201 is inserted, the optical disk recording apparatus first rotates the spindle motor 203 at a desired number of revolutions, emits a laser diode 207, and performs focus servo,
Apply tracking servo. Next, the pickup module is moved to the emboss zone on the innermost circumference of the disc. Then, the reproducing operation is performed in the emboss zone, and the reflected light from the optical disc 201 is received by the reflected light receiving unit 206. The signal received by the reflected light receiving unit 206 is calculated by the reflected light calculation unit 208 into an RF signal that is the sum of the reflected light. The obtained RF signal is A / D converted by the reflected light A / D converter 209, the signal amplitude of the RF signal is measured, and the RF signal amplitude value and the current radial tilt value are held in pairs. In a similar process, the radial tilt control unit 211 outputs a signal for tilting the objective lens 205 to the focus driving unit 212, and the RF signal amplitude is measured each time the radial tilt is varied by five tilts.

  FIG. 18A shows a diagram showing the relationship between radial tilt and RF signal amplitude. When radial tilting of the objective lens is performed in the radial direction as shown in FIG. 18B, the obtained radial tilt values at the five inclinations and the RF signal amplitude values corresponding to the radial tilt values become points shown in FIG. 18A. If these points are parabolically approximated using the method of least squares, an upwardly convex parabola is obtained, and the apex of the parabola is determined as the optimum radial tilt value.

  In addition to the method for obtaining the maximum RF signal as described above, as a method for searching for an optimum radial tilt, for example, focus driving as disclosed in Japanese Patent Laid-Open No. 2001-195663 (Patent Document 1) or the like. There are a method of searching from a change in voltage, a method of searching for a radial tilt at which an error rate and a jitter value are minimized, as disclosed in Japanese Patent Laid-Open No. 2003-263762 (Patent Document 2) and the like.

  Now, an optical system of an optical pickup that performs recording / reproduction of an optical disk has aberration due to processing accuracy of each component optical component, adjustment deviation at the time of assembling the optical pickup, and the like.

  Since the aberration affects the quality of the focused spot on the objective lens and greatly affects the recording / reproducing characteristics of the optical disc, it is necessary to construct an optical system with very little aberration.

  As for coma, which is a component of the aberration, a method is generally used in which coma is canceled and reduced by tilting the objective lens with respect to a reference disk during assembly adjustment. As a result, the objective lens Will be tilted. Hereinafter, the inclination at the time of assembly adjustment is referred to as an initial inclination of the objective lens.

  The coma generated by the relative tilt between the objective lens and the reference disk is the third power of the numerical aperture (NA) of the objective lens, the protective layer thickness of the information recording surface of the optical disk, and the reciprocal of the wavelength. Are generally known to be proportional to each other, and are generated by the relative inclination of the objective lens and the reference disk with respect to the optical disks (BD, HD-DVD, DVD, CD) that are generally used at present. The amount of coma aberration to be performed is shown in FIG. Hereinafter, the amount of coma generated due to the relative tilt between the objective lens and the reference disk is referred to as disk tilt sensitivity of coma aberration.

  By the way, in the current optical disk drive apparatus, a combo drive (multi-drive), a super multi-drive (super multi-drive), a hyper multi-drive (hyper multi-drive) (multi-drive) corresponding to the recording or reproduction of a plurality of types of optical disks. hyper multi-drive) is generally used, and it is indispensable to record or reproduce a plurality of types of optical disks with a single optical pickup.

  The optical system configuration of the optical pickup in this case is various. For example, the optical axis of the light emitted from the light source corresponding to each of CD and DVD is aligned by a prism, passed through a common optical path, and then shared by a common objective lens. A configuration for condensing light on the surface of the optical disk is used.

  Furthermore, in addition to the first objective lens for CD and DVD, a system in which a second objective lens is provided on a common objective lens actuator for recording or reproducing a Blu-ray disc has been put into practical use. A blue-violet laser beam as a light source is condensed on the surface of the optical disk by the second objective lens, and digital information is recorded or reproduced.

  Further, in the future, it is considered that a pickup capable of recording or reproducing Blu-ray discs and HD-DVDs will be put into practical use. In this case, for example, the numerical aperture of the Blu-ray disc and HD-DVD, cover, By adopting an optical arrangement for correcting an optical difference due to a difference in layer thickness, a method of configuring an optical pickup with a common light source and an optical system can be considered.

In addition, the optical axis of the light emitted from the light source corresponding to each of CD, DVD, Blu-ray disc, and HD-DVD is aligned by a prism or the like to correct optical differences due to differences in numerical aperture and cover layer thickness. By adopting the arrangement, it is considered that a method of condensing on the surface of the optical disk by the common objective lens after passing through the common optical path is considered to be put into practical use.
JP 2001-195663 A JP 2003-263964 A

  Now, in the optical pickup corresponding to any one of a plurality of optical discs such as CD, DVD, Blu-ray disc, and HD-DVD, the coma aberration amount of the optical system corresponding to each optical disc due to the aberration of the components of the optical system. Further, as shown in FIG. 19, the disc tilt sensitivity of coma aberration depends on the numerical aperture of the objective lens corresponding to each optical disc, the thickness of the protective layer on the information recording surface of the optical disc, and the wavelength. Therefore, the angle for correcting the coma aberration is different for each optical disc, and as a result, the initial tilt of the objective lens is different.

  For example, consider a case where a pickup capable of recording or reproducing a Blu-ray disc and an HD-DVD is configured by a common light source and optical system.

  Since the optical system and the light source are common, the coma aberration of the optical system is substantially the same for both Blu-ray discs and HD-DVDs. However, as shown in FIG. 19, because the disc tilt sensitivity of the coma aberration is different by 2.7 times, the initial tilt of the objective lens of the Blu-ray disc is different by 2.7 times from the HD-DVD. Become.

  Since the objective lens is common, the initial tilt of the objective lens at the time of assembly adjustment cannot be set to be optimal for both Blu-ray disc and HD-DVD, and in the optical system for at least one disc Assembling is performed with the coma remaining.

  By the way, if the conventional technique is implemented, the optimum value of the initial tilt amount is detected each time each optical disk is mounted, and the initial tilt is adjusted based on the detected value, the recording or reproduction by the remaining coma aberration is performed. Performance degradation can be reduced.

  However, as described above, when the method of adjusting the initial tilt amount based on the detected jitter or the like is performed every time an optical disc is mounted, it takes time for the optical disc apparatus to perform recording or reproduction. There is a problem that it takes a long time to start.

  In view of the above-described problems in the prior art, an object of the present invention is to provide a tilt correction processing method capable of reliably detecting and adjusting a tilt amount in a short time, and adopting it. An optical pickup, an optical disc drive, an optical information recording / reproducing apparatus, and a tilt adjusting method capable of starting recording or reproducing in a short time.

  In order to solve the above technical problem, the present invention provides an optical pickup having the following configuration.

According to the first aspect of the present invention, there is provided an optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction and changing an inclination of an optical axis of the objective lens;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
A tilt angle storage unit having tilt information having information related to the tilt of the objective lens according to the type of the optical information medium;
Based on the result of discriminating the type of the optical information medium by the optical information medium discriminating unit, the objective lens actuator is tilted to an angle set based on the tilt information of the tilt angle storage unit. An optical pickup including an objective lens tilt setting unit that controls driving is provided.

According to the second aspect of the present invention, there is provided an optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
An aberration correction element for correcting the aberration of the light emitted from the objective lens;
An aberration correction value storage unit having aberration information for storing information on the correction value of the aberration of the light according to the type of the optical information medium;
Based on the result of discriminating the type of the optical information medium by the optical information medium discriminating unit, driving the aberration correction element to a correction value set by the aberration information owned by the aberration correction value storage unit, A coma aberration setting unit for offsetting the coma aberration of the output light of the objective lens by a certain amount;
An optical pickup comprising:

According to a third aspect of the present invention, there is provided an optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction and changing an inclination of an optical axis of the objective lens;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
A tilt angle storage unit having tilt information having information related to the tilt of the objective lens according to the type of the optical information medium;
Based on the result of discriminating the type of the optical information medium by the optical information medium discriminating unit, the objective lens actuator is tilted to an angle set based on the tilt information of the tilt angle storage unit. An objective lens tilt setting unit for driving control; a driving state detection unit for detecting a recording or reproducing state of the optical information medium;
There is provided an optical pickup comprising: a coma aberration correcting unit that controls driving of the aberration correcting element according to a driving state by the driving state detecting unit and offsets a coma aberration of light emitted from the objective lens by a certain amount.

According to a fourth aspect of the present invention, there is provided an optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction and changing an inclination of an optical axis of the objective lens;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
An aberration correction element for correcting the aberration of the light emitted from the objective lens;
An aberration correction value storage unit having aberration information for storing information on the correction value of the aberration of the light according to the type of the optical information medium;
A driving state detection unit for detecting a recording or reproducing state of the optical information medium;
There is provided an optical pickup comprising: a tilt correction control unit that drives and controls the objective lens actuator so that the objective lens is tilted according to a drive state by the drive state detection unit.

  According to each aspect of the present invention, the optimum tilt correction amount is obtained by optimizing the initial inclination of the optical axis of the light emitted from the objective lens promptly when a plurality of optical disks are loaded. It is possible to perform the calculated tilt adjustment in a short time. Therefore, it is possible to shorten the time until the optical disc apparatus starts recording or reproduction, and to improve the recording or reproduction performance with respect to the tilt amount of the disc.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, before describing the embodiment of the present invention, the definition of coordinate axes in the optical pickup according to the present embodiment will be clarified. The T axis is perpendicular to the optical axis of the objective lens and is substantially perpendicular to the track groove extending direction of the optical disk, and moves the optical pickup when recording / reproducing the inner and outer circumferences of the optical disk. Direction (tracking direction). The F axis is the optical axis direction of the objective lens, that is, the focusing direction. The Y axis is a direction perpendicular to the T axis, and is a direction substantially parallel to the track groove extending direction of the optical disc at the position of the objective lens.

(First embodiment)
FIG. 1 is a perspective view showing an external configuration of an optical pickup according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the optical pickup shown in FIG. The optical pickup 100 includes an optical base 101 and an objective lens actuator 102 fixed to the upper side of the optical base 101 in the figure. The optical base 101 is engaged with a pair of guide rails 110 by engaging portions 111 located at both ends in the Y-axis direction, and is configured to be movable in the tracking direction along the guide rails 110.

  FIG. 3 is a schematic diagram schematically showing the configuration of the optical system of the optical pickup shown in FIG. FIG. 4 is a diagram showing an internal configuration of an optical base used in the optical pickup shown in FIG. Each member constituting the optical system of the optical pickup is mounted on the optical base 101 and the objective lens actuator 102.

  The optical pickup 100 according to the present embodiment includes a first optical system 120 and a second optical system 140. The first optical system 120 is an optical system for recording or reproducing next-generation optical discs 180 such as Blu-ray discs and HD-DVDs, and the second optical system 140 performs recording or reproduction of DVDs 181 and CD182. This is an optical system.

  As will be described later, since the HD-DVD has characteristics that the cover layer thickness and the numerical aperture are similar to those of the DVD 181, the second optical system 140 may perform recording or reproduction.

  First, the first optical system 120 will be described. In the first optical system 120, the first light source 121 emits a light beam 129 having a wavelength of 405 nm, for example. The light beam 129 emitted from the first light source 121 reaches the collimating lens 123 with the optical path being bent by the polarization beam splitter 122. The light beam 129 that has passed through the polarization beam splitter 122 is linearly polarized light, and its divergence is converted by the collimating lens 123. The light beam is bent in a direction perpendicular to the optical disk 180 having a high recording density by a first inclined surface 124a of a rising prism 124 having a substantially triangular cross section as an example of a bending mirror. The light beam bent by the rising prism 124 passes through a λ / 4 wavelength plate 125, which is an example of a wavelength plate, and becomes circularly polarized light. Thereafter, the light beam 129 is converged on the recording surface of the optical disc 180 by the objective lens 126 to form a light spot.

  The first light beam that has reached the optical disc 180 is reflected on the recording layer of the optical disc 180 with a reflectance corresponding to the state of the recording layer. The first light beam reflected by the recording layer of the optical disc 180 passes through the objective lens 126 again and reaches the λ / 4 wavelength plate 125. When the light beam that has reached the λ / 4 wavelength plate 125 passes through the λ / 4 wavelength plate 125, it is a straight line that is orthogonal to the forward path (that is, the linear polarization of the light beam emitted from the collimating lens 123 and emitted to the prism 124). Converted to polarized light. Thereafter, the light passes through the collimating lens 123 and is reflected by the first reflecting surface 124 a of the rising prism 124 to the polarization beam splitter 122. Since this light beam has a change direction different from that of the forward light beam, it is reflected by the polarization beam splitter 122 and enters the photodetector 127. In the photodetector 127, photoelectric conversion is performed by the photodetector 127, and an electric signal for obtaining an information signal and a servo signal (a focus error signal for focus control and a tracking signal for tracking control) is extracted.

  The objective lens 126 used in the first optical system 120 has an NA of 0.85 or a larger numerical aperture. Since the numerical aperture is large, when recording or reproducing is performed on the optical disc 180, spherical aberration is remarkably generated with respect to the thickness of the transparent substrate that fills from the light incident surface to the information recording surface. In this embodiment, by moving the collimating lens 123 in the optical axis direction of the collimating lens 123, the divergence convergence degree of light traveling from the collimating lens 123 to the objective lens 126 is changed. Since the spherical aberration changes when the divergence / convergence degree of the light incident on the objective lens 126 changes, the spherical aberration caused by the cover layer thickness difference is corrected using this. The optical base 101 includes a driving device having a driving motor 128 as a mechanism for moving the collimating lens 123 in the optical axis direction of the collimating lens 123. As the drive motor 128, specifically, a stepping motor, a brushless motor, or the like can be used. As shown in FIG. 4, the optical base 101 is provided with a holder 123 a that holds the collimating lens 123 and a driving mechanism 123 b that transmits the driving force of the driving motor 128 to the holder 123 a. The holder 123 a that holds the collimating lens 123 is supported by two guide shafts 115 extending in the optical axis direction of the collimating lens, and the collimating lens moves along the guide shaft 115. In order to reduce rattling when moving along the guide shaft 115, the holder 123a is supported by the guide shaft 115 while being urged by a spring. In order to reduce the number of parts, the lens holder 123a may be formed by integral molding with the collimating lens 123.

  Next, the second optical system 140 will be described. In the second optical system 140, the second laser unit 141 is used as a second light source (for example, a red light source). The second laser unit 141 is a member in which a light source that emits laser light and a photodetector that detects the laser light are integrally configured. The light beam 148 emitted from the second laser unit 141 reaches the half mirror 145. The light beam 148 is bent by the half mirror 145, the parallelism is converted by the collimator lens 143 (for example, into substantially parallel light), and guided to the rising prism 124. The rising prism 124 bends the optical axis in a direction perpendicular to the optical disk 181 (for example, DVD) having a low recording density by the second inclined surface 124b. The objective lens 144 converges the light beam 148 on the recording surface of the optical disk 181 to form a light spot. The light beam reflected by the recording surface of the optical disc 181 with a reflectivity according to the state of the recording layer follows the original optical path in the reverse direction and reaches the second laser unit 141 which is a photodetector. The light beam 148 is photoelectrically converted by the second laser unit 141 to obtain an electrical signal for obtaining an information signal and a servo signal (a focus error signal for focus control and a tracking signal for tracking control).

  As described above, in the first optical system 120, the light source 121 that emits laser light and the photodetector 127 for detecting the laser light reflected by the optical disk 180 are configured as separate members. According to 122, the optical path must be different between the forward path and the return path. For this purpose, a λ / 4 wavelength plate 125 is provided as a member for changing the optical path of the laser beam, and the optical path is changed by changing the polarization of the laser beam when passing through the λ / 4 wavelength plate 125. Can do. On the other hand, in the second optical system, both the light source for emitting laser light provided for the optical disks 181 and 182 and the detector for detecting the laser light reflected by the optical disks 181 and 182 are unitized. The second laser unit 141 is composed of one member. For this reason, it is not necessary to change the optical path in the forward path and the return path, and therefore, it is not necessary to change the polarization of the laser light in the forward path and the return path. Therefore, it is not necessary to provide the λ / 4 wavelength plate in the second optical system 140.

  The objective lens actuator 102 includes an actuator base 60 and a suspension unit 61 as shown in FIGS. 5A, 5B, and 6.

  The actuator base 60 is disposed in parallel to a base plate 63 having an opening 62 for transmitting the laser light reflected in the F-axis direction by the rising prism 124 so as to face the Y-axis direction with the opening 62 interposed therebetween. A pair of magnet portions 64. The magnet portion 64 includes a pair of magnet support portions 65 erected on the base plate 63 and magnets 66 disposed on the surfaces of the magnet support portions 65 on the opening 62 side. The movable body 30 of the suspension unit 61 is arranged between the pair of magnet parts 64, and the position of the movable body 30 of the suspension unit 61 is adjusted by supplying current to the coil 32 of the movable body 30 as will be described later. It can be performed. By moving the movable body 30, the objective lenses 4a and 4b can be moved in the focus direction and the tracking direction, and the tilt of the objective lens can be changed.

  The suspension unit 61 includes a movable body 30 configured to be movable with respect to the actuator base 60, and a suspension holder 40 that supports the movable body 30 so as to be movable. The movable body 30 is supported by six suspension wires 42 extending from the suspension holder 40, and the direction in which the six suspension wires 42 bend with respect to the suspension holder 40, that is, the six suspension wires 42. It can move in a direction perpendicular to the extending direction. The suspension unit 61 is assembled to the actuator base 60 so that the movable body 30 is positioned between the magnets 66 and the suspension holder 40 is positioned outside the magnet unit 64.

  The movable body 30 includes two lens barrels 33a and 33b extending in the F direction. When the suspension unit 61 is assembled to the actuator base 60, the lens barrel 33 a of the movable unit 30 is positioned above the wave plate 125. An objective lens 126 is provided on the lens barrel 33a of the first optical system 120, and an objective lens 144 is provided on the lens barrel 33b of the second optical system 140. A hologram element 34 is provided in the lens barrel 33b of the second optical system 140. The hologram element 34 is divided by diffracting part of the laser light reflected on the optical disk of the second optical system 140, and focused. Generate an error signal or tracking error signal.

  The objective lens 144 for the second optical system 140 is fixed to the movable body 30 while being fixed to the objective lens holder 35 as shown in FIG. 5B. The objective lens holder 35 has a tapered surface on the side of the lens barrel 33b, and the mounting angle can be adjusted when the objective lens holder 35 is fixed to the lens barrel 33b. The reason why the fixing direction of the objective lens 144 and the movable body 30 can be adjusted is as follows. When the two objective lenses 126 and 144 are fixed to the movable body 30, fine adjustment in the optical axis direction of the objective lenses 126 and 144 is required by the two optical systems 120 and 140, respectively. For this reason, in the present embodiment, the objective lens 126 for the first optical system 120 is used as a reference, and the objective lens 144 for the second optical system 140 is finely adjusted, so that the fineness of both optical systems can be reduced. You can make adjustments.

  The objective lens 126 of the first optical system 120 and the objective lens 144 of the second optical system are held by the movable body 30 in a state of being arranged substantially parallel to the Y direction, that is, the extending direction of the track groove of the optical disk. When the two objective lenses are arranged in a direction perpendicular to the extending direction of the track groove, a spindle motor 164 that rotates the optical discs 181 and 182 by an inner objective lens that is not used when the optical disc moves to the outermost or innermost circumference of the optical disc (see FIG. 7A) and the outside lens may interfere with the exterior of the device. By arranging the objective lenses 126 and 144 in the Y direction, different types of discs can be interchanged without the optical pickup hitting a motor that rotates the optical disc.

  Further, the movable body 30 is provided with three coils 32 for adjusting the position of the movable body 30 on the surface facing the magnet 66 when the suspension unit 61 is assembled to the actuator base 60. That is, since the magnet of the magnet part 64 provided in the actuator base 60 and the coil 32 provided in the suspension unit 61 are disposed to face each other, the movable body 30 can be moved by passing a current through the coil. it can.

  Electric power supplied to the coil 32 is performed via the suspension wire 42. The coil 32 is provided with a coil 32a for the focusing direction (direction perpendicular to the surface of the optical disk) and a coil 32b for the tracking direction (radial direction of the disk), and a current is passed through the suspension wire 42 to the coil 32. Can be used to finely adjust the focusing direction and the tracking direction position.

  Note that the optical axes of the light beam 129 and the light beam 148 or the light beam 149 rising and entering the prism 124 are preferably parallel to each other. With this configuration, the two reflecting surfaces 124a and 124b of the rising prism 124 can be configured symmetrically so that the incident angle on the objective lens is parallel to the optical axis of the objective lens. Since the two reflecting surfaces of the rising prism 124 can be configured symmetrically, the rising prism 124 can be created more easily and at low cost.

  Next, the functional operation of the optical disc apparatus equipped with the optical pickup will be described. FIG. 7 is a block diagram paying attention to the operation function of the optical disk apparatus on which the optical pickup of FIG. 1 is mounted.

  In FIG. 7, the disk motor 2 mounts optical disks 180, 181, and 182 on its rotation shaft and rotates them at a predetermined rotation speed.

  On the other hand, the light source 3 is a functional block corresponding to the light source 121 and the second laser unit 141 shown in FIG. 3, and irradiates the optical discs 180, 181, and 182 with laser light (broken lines in the figure). The irradiated laser light is condensed on the information recording surfaces of the optical discs 180, 181 and 182.

  The photodetector 5 is a functional block corresponding to the photodetector 127 and the second laser unit 141 shown in FIG. 3, and detects the reflected light of the irradiated laser light from the optical discs 180, 181, and 182. Based on this, a light reception signal is generated.

  Each processing block shown below is a functional block configured as an integrated circuit mounted on the optical pickup. The disc signal detection circuit 6 detects and calculates a predetermined signal recorded on the information recording surfaces of the optical discs 180, 181, and 182 based on the received light signal generated by the photodetector 5.

The tilt actuator 7 functions to tilt the objective lens 4 with respect to the optical axis of the laser beam. Specifically, it is composed of the objective lens actuator 102 and focuses on the case where the objective lens 4 (4a, 4b) is tilted during the movement of the movable body 30. Further, the tilt actuator driver 10 functions to drive the tilt actuator 7. The tilt control circuit 9 functions to send a drive signal for driving the tilt actuator 7 to the tilt actuator driver 10. The tilt calculator 8 functions to set a tilt amount, which is a relative tilt between the optical discs 180, 181 and 182 and the laser beam, with respect to the tilt control circuit 9.

  The focus actuator 12 is a device for driving the objective lens 4 in a direction perpendicular to the information recording surfaces of the optical discs 180, 181, and 182. Specifically, the objective lens actuator 102 is configured, and attention is paid to the case where the objective lens 4 (4a, 4b) is moved in the F-axis direction in the movement of the movable body 30. The focus error signal detection circuit 13 generates a so-called focus error signal, which is an error between the in-focus point of the objective lens 4 and a predetermined position, based on the light reception signal in the photodetector 5. The focus drive signal generation circuit 14 generates a focus servo signal for the objective lens 4 to focus on the optical discs 180, 181, and 182 based on the output of the focus error signal detection circuit 13. The focus actuator driver 15 drives the focus actuator 12 based on the signal sent from the focus drive signal generation circuit 14.

  FIG. 8 is a flowchart showing the operation of the optical disk apparatus according to the present invention shown in FIG. 7. Hereinafter, the operation and characteristics of each block will be described in detail with reference to FIG.

  In FIG. 8, after confirming that the disc is loaded in step # 1, disc discrimination processing is performed in which the type of the disc loaded is discriminated in step # 2.

  Hereinafter, the disk discrimination process in step # 2 will be described in detail.

  FIG. 9 is a diagram showing the positional relationship between the objective lens and the optical disc when a focus error signal is generated when the first disc is loaded. FIG. 10 is a diagram showing the positional relationship between the objective lens and the optical disc when a focus error signal is generated when the second disc is loaded, and the thickness of the protective layer is different from that of the first disc. 9 and 10, D1 and D2 indicate optical disk substrates, and R1 and R2 indicate reflective film layers, respectively. As shown in FIGS. 9 and 10, since the distance from the optical disk surface to the reflective film layer, that is, the thickness of the protective layer (cover layer thickness) differs between the first disk and the second disk, the reflective film layer of the optical disk. The moving distance of the objective lens for making the focal point of the light beam coincide with each other is different as indicated by d1 and d2.

  A split sensor (not shown) is provided in the photodetector 5 of the optical pickup shown in FIG. The signals detected by each of these divided sensors are differentially amplified by the differential amplifier of the focus error signal detection circuit 13 to generate a focus error signal. A comparator (not shown) of the focus error signal detection circuit 13 slices the focus error signal at an appropriate level, generates an S-shaped detection signal indicating that the focus error signal has been detected, and generates a focus drive signal. Output to the circuit 14.

  11A and 11B are timing charts showing the focus error signal and the S-shaped detection signal in the optical disc apparatus shown in FIGS. 9 and 10, and FIG. 11A shows the case where the loaded optical disc is the first disc. FIG. 5 shows waveforms of a focus error signal and an S-shaped detection signal that are generated when the objective lens is brought close to the optical disc at a constant speed. FIG. 11B shows waveforms of a focus error signal and an S-shaped detection signal that are generated when the objective lens is brought close to the optical disk at a constant speed when the loaded optical disk is the second disk.

  As shown in FIGS. 11A and 11B, the focus error signal has a substantially “S” -shaped waveform. Further, the S-shaped detection signal is generated by a comparator (not shown) of the focus error signal detection circuit 13 in FIG. 1 and becomes a pulse waveform indicating the time when the focus is achieved. 11A and 11B, the S-shaped detection signal at time t1 or t3 corresponds to the first focusing signal, and the S-shaped detection signal at time t2 or t4 corresponds to the second focusing signal.

  As shown in FIGS. 11A and 11B, when the objective lens is gradually brought closer to the optical disc from time 0, the first disc (in the case shown in FIG. 11A) and the second disc (in the case shown in FIG. 11B). In both cases, the focus error signal and the S-shaped detection signal generated by the reflected light on the surface of the optical disc are time t1 for the first disc (in the case shown in FIG. 11A) and in the second disc (in the case shown in FIG. 11B). It is detected at time t3.

  Further, the focus error signal and the S-shaped detection signal due to the reflection of the reflection film layer detected when the objective lens is brought close to the optical disk are the distance from the disk surface to the reflection film layer in the first disk and the second disk. Is different at time t2 for the first disk (in the case shown in FIG. 11A) and at time t4 in the second disk (in the case shown in FIG. 11B). It is detected at a fast timing. This is because, as shown in FIGS. 9 and 10, the first disk has a shorter distance from the disk surface to the reflective film layer, that is, the protective layer. The specific detection time is measured by the counter circuit 16 in FIG. 7, and the disc type is determined based on the difference in the thickness of the protective layer of the disc. This information is sent to the controller 17 in FIG. 7, and the disc discrimination process is completed.

  Next, as step # 3 in FIG. 8, based on the result of the disc determination process performed previously, the objective lens actuator performs initial tilt correction for tilting the objective lens by a preset amount.

  In FIG. 7, the controller 17 calls the optimum tilt correction amount stored in the memory 11 from the disk information, and sets the offset value of the tilt control current to the offset generation circuit 18. FIG. 12 is a diagram illustrating a configuration of information related to the optimum tilt correction amount stored in the memory. As shown in FIG. 12, information on the optimum tilt correction amount is stored as information on relative tilt sensitivity (based on a BD single-layer disc) determined according to the type of optical disc to be recorded or reproduced. ing. Further, the optical disk is configured not only to be BD, HD-DVD, DVD, and CD, but also to be different depending on whether it is a single-layer disk or a dual-layer disk. In the example shown in FIG. 12, in the case of a two-layer disc, the focal point of the light spot, which is a reference for measuring the cover layer thickness, is set at an intermediate position between the first and second recording tanks. As a result of the increase in the cover layer thickness of the two-layer disc, the relative tilt sensitivity is set smaller than that of the single-layer disc.

  The offset value derived from the value of the optimum tilt correction amount is added to the focus signal by the adder 19, and the lens tilt is offset by a certain amount.

  As the objective lens actuator, one in which tilt control is performed only in the radial direction where the tilt of the disc is likely to occur due to warpage of the optical disc is often used, and most of the coma aberration of the optical system is the objective lens. There are many cases.

  In such a case, if a mark indicating the coma aberration direction is formed on the objective lens and the mark is arranged so as to face the radial direction of the optical pickup, the coma aberration in the tangential direction can be reduced, and the optical The light collection characteristics of the system can be improved.

  The optimum tilt correction amount is stored in the memory at the time of assembly adjustment of the optical pickup. Specifically, the optimum tilt correction amount is performed in the following procedure.

  First, when assembling and adjusting the optical pickup, the optical axis of the objective lens is arranged and fixed so as to be perpendicular to the information recording surface of the reference disk.

  Next, each reference disk corresponding to the optical pickup is loaded, and an offset current is applied to the tilt drive circuit of the objective lens actuator so that the coma aberration of the light spot condensed on the reference disk is minimized. Shed.

  This offset current value is a current value that realizes the optimum tilt correction, and this value is temporarily stored in the memory 11.

Initially, the optical axis of the objective lens was placed and fixed so as to be perpendicular to the information recording surface of the reference disk, but the objective lens was tilted and fixed so that coma aberration was minimized with respect to any reference disk. The relative value from the position may be stored in the memory.

  As described above, when the storage in the memory is performed at the time of assembling and adjusting the optical pickup, if the memory is mounted on the optical pickup, a means for separately managing data becomes unnecessary, which can increase the production efficiency. it can.

  As a modification, the setting value is not stored as digital information, but is set in, for example, a variable resistor of an electronic circuit mounted on an optical pickup. By switching the variable resistor, the actuator The control current may be changed. Specifically, the variable resistor 50 shown in FIG. 13 is mounted, and the variable resistor 50 is switched by switching the switch with respect to the circuit having the respective resistors 51, 52, 53, 54 according to the discriminated type of the optical disk. The tilt of the objective lens may be changed by changing the resistance value at both ends of the device 50 and changing the control current of the actuator in accordance with the value.

  After the initial tilt setting, which is the third step, is completed, the process further proceeds to a tilt learning step for adjusting the objective lens to the optimum tilt (step # 4).

  After focusing on the optical discs 180, 181, and 182, first, the tilt calculator 8 changes the tilt amount stepwise with respect to the tilt control circuit 9, and the disc signal detection circuit 6 at each set tilt amount. A predetermined signal (including jitter) is detected. Thereafter, the quadratic function is obtained by calculation based on the value of a predetermined signal (including jitter) detected by the disk signal detection circuit 6, that is, by the least square method of the detected value. Based on the calculated quadratic function, an optimum tilt correction amount is calculated. Thereafter, the tilt calculator 8 stores the calculated optimum tilt correction amount in a memory (not shown) of the controller 17 and completes a series of tilt correction processes in FIG.

  The jitter extracts a high-frequency component of the signal, detects a high-pass filter (not shown) and an output signal of the high-pass filter, detects a detector (not shown), and digitizes the output signal of the detector (not shown) A / D It is detected by jitter detection means comprising a converter.

  As described above, the method of performing the tilt learning based on the signal quality of the reflected light from the disc has high accuracy, but the process is complicated, and the tilt learning is performed by detecting the warp of the disc as a simple method. A method is also used.

  A specific method is to first move the objective lens to a first position in the radial direction of the optical information medium, adjust the focal position so that the signal surface of the optical information medium is focused, and then And moving the objective lens to a second position in the radial direction of the optical information medium to adjust the focal position so that the signal surface of the optical information medium is in focus, and the first and second positions. And the inclination of the optical information medium with respect to the optical axis of the optical pickup from the focal positions at the first and second positions.

  The angle of the optical information medium with respect to the optical axis of the optical pickup is adjusted according to the calculation result.

  In either method, the information is recorded in the controller 17 together with information on the radial position of the disc on which the tilt adjustment step has been executed (for example, including disc layer information).

  Thereafter, in the recording or reproducing operation in the optical disc apparatus, the tilt calculator 8 calls the optimum tilt correction amount stored in the controller 17, and based on the stored optimum tilt correction amount, the tilt control circuit 9. The tilt amount of the objective lens 4 is optimally adjusted through the tilt actuator driver 10 and the tilt actuator 7, and a predetermined recording or reproducing operation is performed on the optical disc.

  Here, the predetermined signal in the disc signal detection circuit 6 used for obtaining the optimum tilt correction amount is, for example, any one of a reproduction signal, a wobble signal, and a tracking error signal. The calculated value based on the predetermined signal in the disk signal detection circuit 6 is any one of jitter, error rate, reproduction signal amplitude, wobble signal amplitude, and tracking error signal amplitude.

  In the present embodiment, processing is performed in the order of initial tilt correction in step # 3 and tilt learning in step # 4. However, processing may be performed in order of tilt learning and initial tilt correction. When performing tilt learning, the correction value for tilt learning can be adjusted by adjusting the correction value for initial tilt correction.

  Further, by realizing the process in this embodiment with one integrated circuit, the optical pickup can be reduced in size and weight.

(Second Embodiment)
FIG. 14 is a block diagram paying attention to the operation function of the optical disc apparatus in the second embodiment.

  Unlike the optical disk apparatus shown in FIG. 7, the optical disk apparatus according to the present embodiment is provided with a liquid crystal aberration correction element 20 having a function of correcting the aberration of the optical system instead of the tilt actuator. In other words, in the optical disk apparatus according to the present embodiment, the objective lens actuator 102 only needs to be able to perform movement in the focus and tracking directions, and may not have a configuration that allows tilting of the optical axis of the objective lens.

  The liquid crystal aberration correction element 20 is controlled by a liquid crystal element control circuit 22 according to a command from the controller 17 and is driven by a liquid crystal element driver 21.

  Also in the optical disc apparatus according to the present embodiment, the operation of each block is performed according to the flow of FIG. However, the initial tilt correction in step # 3 and the tilt learning in step # 4 are different in that they are performed by controlling the liquid crystal aberration correction element 20.

  Based on the result of the disc discrimination process obtained by the same processing as in the first embodiment, instead of performing the initial tilt correction by tilting the objective lens by a preset amount by the objective lens actuator, the disc discrimination process Based on the result, the liquid crystal aberration correction element 20 corrects the coma aberration of the optical system by a preset amount.

  The coma correction amount of the optical system aberration is stored in the memory at the time of assembly adjustment of the optical pickup, and specifically, it is performed in the following procedure.

  First, when assembling and adjusting the optical pickup, the optical axis of the objective lens is arranged and fixed so as to be perpendicular to the information recording surface of the reference disk.

  Next, each reference disk corresponding to the optical pickup is loaded, and the control voltage of the liquid crystal aberration correction element 20 is changed so that the coma aberration of the light spot condensed on the reference disk is minimized.

  This control voltage value is a voltage value that realizes optimum coma aberration correction, and this value is stored in the memory.

  Initially, the optical axis of the objective lens was placed and fixed so as to be perpendicular to the information recording surface of the reference disk, but the objective lens was tilted and fixed so that coma aberration was minimized with respect to any reference disk. Then, the control voltage value at that position may be stored in the memory.

The set value is not stored as digital information, but is set in, for example, a variable resistor of an electronic circuit mounted on the optical pickup, and the liquid crystal aberration correction element 20 is controlled by switching the variable resistor. The voltage may be changed.

  After the initial tilt setting, which is the third step, is completed, the process further proceeds to a tilt learning step that minimizes coma generated in the light spot focused on the optical disk from the objective lens by tilting the optical disk. (Step # 4).

  After focusing on the optical discs 180, 181, and 182, first, the liquid crystal aberration correction element controller 22 applies voltage to the liquid crystal aberration correction element stepwise to collect light from the objective lens onto the optical disk. The coma aberration is changed stepwise to the spot, and a predetermined signal (including jitter) is detected by the disc signal detection circuit 6 at each of the set coma aberrations. Thereafter, the quadratic function is obtained by calculation based on the value of a predetermined signal (including jitter) detected by the disk signal detection circuit 6, that is, by the least square method of the detected value. Based on the calculated quadratic function, an optimal coma aberration correction amount is calculated. Thereafter, the liquid crystal aberration correction element controller 22 stores the calculated optimum coma aberration correction amount in the controller 17 and ends the process.

  Thereafter, in the recording or reproducing operation in the optical disc apparatus, the liquid crystal aberration correction element controller 22 calls the optimum coma aberration correction amount stored in the controller 17 and based on the stored optimum coma aberration correction amount. The coma aberration of the light emitted from the objective lens is optimally adjusted by the liquid crystal aberration correction element controller 22, the liquid crystal aberration correction element driver 21, and the liquid crystal aberration correction element 20, and a predetermined recording or reproducing operation is performed on the optical disc. It becomes.

  Other operation processing is the same as in the first embodiment.

  In the present embodiment, the liquid crystal aberration correction element 20 corrects a preset amount and coma aberration of the optical system based on the result of the disc discrimination processing. However, astigmatism and spherical aberration are corrected. Other aberrations may be similarly corrected.

  In the present embodiment, the process is performed in the order of the initial tilt correction in step # 3 and the tilt learning in step # 4. However, the process may be performed in the order of tilt learning and initial tilt correction. In addition, when performing the tilt learning, the correction amount of the tilt learning can be adjusted by adjusting the correction value of the writing inclination correction.

(Third embodiment)
FIG. 15 is a block diagram paying attention to the operation function of the optical disc apparatus in the third embodiment.

  Unlike the optical disk apparatus shown in FIG. 7 and the optical disk apparatus shown in FIG. 14, the optical disk apparatus according to the present embodiment is provided with the tilt actuator and the liquid crystal aberration correction element 20 at the same time.

  The operation of each block is performed according to the flow of FIG. 8, but the initial tilt correction in step # 3 and the tilt learning in step # 4 are performed by the tilt actuator 7, the liquid crystal aberration correction element 20, or the tilt actuator. 7 and the liquid crystal aberration correction element 20 are simultaneously controlled.

  Other contents are the same as those of the optical disk apparatus shown in FIG. 7 and the optical disk apparatus shown in FIG.

(Embodiment 4)
FIG. 16 is a block diagram focusing on the operation function of the optical disc apparatus in the fourth embodiment.

  In the optical disk device shown in FIGS. 7, 14, and 15, only one objective lens and light source are shown. However, when mounted on the optical pickup shown in FIG. 1, that is, two light sources and two objective lenses, or A specific configuration for two or more cases is shown.

  As a specific configuration example of the figure, as described above, the first laser 3 is a blue-violet laser having a wavelength of 405 nm, the second laser 25 is a red laser, and the first objective lens 4 uses a Blu-ray. The disc and the HD-DVD disc are recorded or reproduced, and the DVD and CD are recorded or reproduced by the second objective lens 23.

  As another combination, for example, a Blu-ray disc uses a first light source and a first objective lens to perform recording or reproduction, and HD-DVD, DVD, and CD each share a second A configuration in which recording or reproduction is performed using an objective lens, a configuration in which recording or reproduction is performed using a common objective lens for a Blu-ray disc, HD-DVD, DVD, and CD are conceivable.

  Other contents are the same as those of the optical disk apparatus shown in FIG. 7, the optical disk apparatus shown in FIG. 14, and the optical disk apparatus shown in FIG.

  The optical pickup and the optical information recording / reproducing apparatus of the present invention are useful for an optical information recording / reproducing apparatus using an optical disk such as a magneto-optical recording apparatus or a CD, DVD, HD-DVD, Blu-ray disk apparatus. It can also be applied to optical systems and devices of hologram recording devices and future ultra-high density recording / reproducing devices.

The perspective view which shows the external appearance structure of the optical pick-up concerning embodiment of this invention 1 is an exploded perspective view of the optical pickup of FIG. Schematic diagram schematically showing the configuration of the optical system of the optical pickup of FIG. The figure which shows the internal structure of the optical base used for the optical pick-up of FIG. The top view which shows the structure of the objective lens actuator of the optical pick-up of FIG. Sectional drawing in line VB-VB of FIG. 5A 5A is an exploded perspective view of the objective lens actuator of FIG. 5A. FIG. 1 is a block diagram that focuses on the operation function of an optical disk device that includes the optical pickup of FIG. 7 is a flowchart showing the operation of the optical disc apparatus in FIG. The figure which shows the positional relationship of an objective lens and an optical disk when a focus error signal generate | occur | produces when a 1st disk is loaded. The figure which shows the positional relationship of an objective lens and an optical disk when a focus error signal generate | occur | produces when a 2nd disk is loaded. Timing chart showing focus error signal and S-shaped detection signal corresponding to FIGS. 9 and 10 Timing chart showing focus error signal and S-shaped detection signal corresponding to FIGS. 9 and 10 The figure which shows the structure of the information regarding the optimal tilt correction amount stored in memory The figure which shows the structural example of the variable resistor of the electronic circuit which changes the control current of an actuator The block diagram which paid its attention to the operation | movement function of the optical disk apparatus in 2nd Embodiment The block diagram which paid its attention to the operation | movement function of the optical disk apparatus in 3rd Embodiment The block diagram which paid its attention to the operation | movement function of the optical disk apparatus in 4th Embodiment Radial tilt control block diagram of a conventional optical disk recording apparatus Diagram showing the relationship between radial tilt and RF signal amplitude Diagram showing the relationship between radial tilt and objective lens The figure which shows the coma aberration amount which occurs due to relative inclination of the objective lens and the reference disk

Explanation of symbols

2 disc motor 3 (first) laser 4 (first) objective lens 5 (first) photodetector 6 disc signal detection circuit 7 tilt actuator 8 tilt calculator 9 tilt control circuit 10 tilt actuator driver 11 memory 12 Focus actuator 13 Focus error signal detection circuit 14 Focus drive signal generation circuit 15 Focus actuator driver 16 Counter circuit 17 Controller 18 Offset generation circuit 19 Adder 20 Liquid crystal aberration correction element 21 Liquid crystal aberration correction element driver 22 Liquid crystal aberration correction element controller 23 Second Objective lens 24 second optical detector 25 second laser 26 movable element 101 optical disk 102 pickup module 103 spindle motor 104 focus drive coil 105 objective lens 106 Light receiving unit 107 a laser diode 108 reflected light calculating unit 109 reflected light A / D converter 110 reflected light A / D conversion value comparing unit 111 radial tilt controller 112 focus driving section 180, 181, 182 optical disc

Claims (23)

An optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction and changing an inclination of an optical axis of the objective lens;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
A tilt angle storage unit having tilt information having information related to the tilt of the objective lens according to the type of the optical information medium;
Based on the result of discriminating the type of the optical information medium by the optical information medium discriminating unit, the objective lens actuator is tilted to an angle set based on the tilt information of the tilt angle storage unit. An optical pickup comprising: an objective lens tilt setting unit that controls driving. And a driving state detecting unit for detecting a recording or reproducing state of the optical information medium;
The optical pickup according to claim 1, further comprising: a tilt correction control unit that drives and controls the objective lens actuator so that the objective lens is tilted according to a driving state by the driving state detection unit.   The optical information medium, which is a first optical disk having a numerical aperture of 0.85 and a cover layer thickness of 0.1 mm, and a second optical disk having a numerical aperture of 0.65 and a cover layer thickness of 0.6 mm, is used as a common light source and The optical pickup according to claim 1, wherein the optical pickup is configured to perform recording or reproduction using the objective lens. A plurality of the objective lenses are provided corresponding to the plurality of light sources,
A first optical disk with a numerical aperture of 0.85 and a cover layer thickness of 0.1 mm and a second optical disk with a numerical aperture of 0.65 and a cover layer thickness of 0.6 mm are recorded using a first light source and a first objective lens. Or replay,
A third optical disk having a numerical aperture of 0.60 and a cover layer thickness of 0.6 mm and a fourth optical disk having a numerical aperture of 0.45 and a cover layer thickness of 1.2 mm are recorded using a second light source and a second objective lens. The optical pickup according to claim 1, wherein the optical pickup is configured to perform reproduction. A plurality of the objective lenses are provided corresponding to the plurality of light sources,
Recording or reproduction of a first optical disk having a numerical aperture of 0.85 and a cover layer thickness of 0.1 mm using a first light source and a first objective lens,
A second optical disc having a numerical aperture of 0.65 and a cover layer thickness of 0.6 mm, a third optical disc having a numerical aperture of 0.60 and a cover layer thickness of 0.6 mm, and a second optical disc having a numerical aperture of 0.45 and a cover layer thickness of 1.2 mm. The optical pickup according to claim 1, wherein the optical disk is configured to record or reproduce the four optical disks using a second light source and a second objective lens.   An optical disk drive using the optical pickup according to claim 1.   7. An optical information recording / reproducing apparatus using the optical disc drive according to claim 6. A tilt adjustment method for adjusting a tilt angle of the objective lens using the optical pickup according to claim 2,
Prior to recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read tilt information that is information relating to the tilt of the objective lens according to the type of the optical information medium stored in the tilt angle storage unit,
Based on the result of the type determination of the optical information medium, tilt the objective lens to an angle set based on the tilt information possessed by the tilt angle storage unit,
After the start of recording or reproduction of the optical information medium, the recording or reproduction state is detected,
A method for adjusting the tilt of the objective lens, wherein the objective lens actuator is driven and controlled to further adjust the tilt of the objective lens according to the detected recording or reproducing state of the optical information medium. A tilt adjustment method for adjusting a tilt angle of the objective lens using the optical pickup according to claim 2,
When recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read the tilt information stored in the tilt angle storage unit,
Detecting the recording or reproducing state of the optical information medium;
When the objective lens is driven and controlled according to the detected recording or reproducing state of the optical information medium, the inclination amount of the objective lens is adjusted by adjusting the amount of inclination shown in the read tilt information. A method for adjusting the tilt of the objective lens, wherein the objective lens actuator is driven and controlled to be corrected and adjusted. An optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
An aberration correction element for correcting the aberration of the light emitted from the objective lens;
An aberration correction value storage unit having aberration information for storing information on the correction value of the aberration of the light according to the type of the optical information medium;
Based on the result of discriminating the type of the optical information medium by the optical information medium discriminating unit, driving the aberration correction element to a correction value set by the aberration information owned by the aberration correction value storage unit, A coma aberration setting unit for offsetting the coma aberration of the output light of the objective lens by a certain amount;
Optical pickup with And a driving state detecting unit for detecting a recording or reproducing state of the optical information medium;
11. The light according to claim 10, further comprising: a coma aberration correcting unit that drives and controls the aberration correction element according to a driving state by the driving state detection unit to offset a coma aberration of light emitted from the objective lens by a certain amount. pick up.   The optical pickup according to claim 10, wherein the aberration correction element includes a liquid crystal element.   The optical pickup according to claim 12, wherein the liquid crystal element is configured to be capable of correcting both coma and spherical aberration according to the type of the optical information medium. A tilt adjustment method for correcting coma aberration of light emitted from the objective lens using the optical pickup according to claim 11,
Prior to recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read out information related to the correction value of the aberration of the light according to the type of the optical information medium stored in the aberration correction value storage unit,
Based on the result of the type determination of the optical information medium, the aberration correction element is driven and controlled to a correction value set based on the aberration correction value possessed by the aberration correction value storage unit,
After the start of recording or reproduction of the optical information medium, the recording or reproduction state is detected,
A tilt adjustment method in which the aberration correction element is driven and controlled to offset a coma aberration of light emitted from the objective lens by a certain amount in accordance with the detected recording or reproducing state of the optical information medium. A tilt adjustment method for correcting coma aberration of light emitted from the objective lens using the optical pickup according to claim 11,
When recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read out information related to the correction value of the aberration of the light according to the type of the optical information medium stored in the aberration correction value storage unit,
After the start of recording or reproduction of the optical information medium, the recording or reproduction state is detected,
When the objective lens is driven and controlled according to the detected recording or reproducing state of the optical information medium, the aberration correction element is driven and controlled by adjusting an amount based on the read correction value. A tilt adjustment method in which the coma aberration of the light emitted from the objective lens is offset by a certain amount. An optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction and changing an inclination of an optical axis of the objective lens;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
A tilt angle storage unit having tilt information having information related to the tilt of the objective lens according to the type of the optical information medium;
Based on the result of discriminating the type of the optical information medium by the optical information medium discriminating unit, the objective lens actuator is tilted to an angle set based on the tilt information of the tilt angle storage unit. An objective lens tilt setting unit for driving control; a driving state detection unit for detecting a recording or reproducing state of the optical information medium;
An optical pickup comprising: a coma aberration correcting unit that drives and controls the aberration correcting element according to a driving state by the driving state detecting unit, and offsets a coma aberration of light emitted from the objective lens by a certain amount. A tilt adjustment method for adjusting a tilt angle of the objective lens using the optical pickup according to claim 16,
Prior to recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read tilt information that is information relating to the tilt of the objective lens according to the type of the optical information medium stored in the tilt angle storage unit,
Based on the result of the type determination of the optical information medium, tilt the objective lens to an angle set based on the tilt information possessed by the tilt angle storage unit,
After the start of recording or reproduction of the optical information medium, the recording or reproduction state is detected,
A tilt adjustment method in which the aberration correction element is driven and controlled to offset a coma aberration of light emitted from the objective lens by a certain amount in accordance with the detected recording or reproducing state of the optical information medium. A tilt adjustment method for adjusting a tilt angle of the objective lens using the optical pickup according to claim 16,
When recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read the tilt information stored in the tilt angle storage unit,
Detecting the recording or reproducing state of the optical information medium;
When the objective lens is driven and controlled in accordance with the detected recording or reproducing state of the optical information medium, the aberration correction element is driven and controlled while adjusting the amount of tilt indicated by the read tilt information. Then, a tilt adjustment method in which the coma aberration of the light emitted from the objective lens is offset by a certain amount. An optical pickup capable of recording or reproducing a plurality of types of optical information media,
Single or multiple light sources;
An objective lens for condensing the light from the light source onto the optical information medium;
An objective lens actuator capable of moving the objective lens in a focus direction and a tracking direction and changing an inclination of an optical axis of the objective lens;
An optical information medium discriminating unit for discriminating a type of the optical information medium at the start of recording or reproduction of the optical information medium;
An aberration correction element for correcting the aberration of the light emitted from the objective lens;
An aberration correction value storage unit having aberration information for storing information on the correction value of the aberration of the light according to the type of the optical information medium;
A driving state detection unit for detecting a recording or reproducing state of the optical information medium;
An optical pickup comprising: a tilt correction control unit that drives and controls the objective lens actuator such that the objective lens is tilted according to a driving state by the driving state detection unit. A tilt adjustment method for adjusting a tilt angle of the objective lens using the optical pickup according to claim 19,
Prior to recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read out information related to the correction value of the aberration of the light according to the type of the optical information medium stored in the aberration correction value storage unit,
Based on the result of the type determination of the optical information medium, the aberration correction element is driven and controlled to a correction value set based on the aberration correction value possessed by the aberration correction value storage unit,
After the start of recording or reproduction of the optical information medium, the recording or reproduction state is detected,
A method for adjusting the tilt of the objective lens, wherein the objective lens actuator is driven and controlled to further adjust the tilt of the objective lens according to the detected recording or reproducing state of the optical information medium. A tilt adjustment method for adjusting a tilt angle of the objective lens using the optical pickup according to claim 19,
When recording or reproducing the optical information medium, the optical information medium determination unit determines the type of the optical information medium,
Read out information related to the correction value of the aberration of the light according to the type of the optical information medium stored in the aberration correction value storage unit,
After the start of recording or reproduction of the optical information medium, the recording or reproduction state is detected,
When the objective lens is driven and controlled in accordance with the detected recording or reproducing state of the optical information medium, the amount of inclination indicated in the information related to the read correction value of the aberration of the light is adjusted. A tilt adjustment method for the objective lens, wherein the objective lens actuator is driven and controlled so as to correct and adjust the tilt of the objective lens. The optical information medium discriminating unit
From the reflected light from the optical information medium detected by the optical pickup, a first focus signal indicating that the light beam is focused near the surface of the optical information medium, and the light beam is the reflective film layer. A signal processing unit for detecting a second in-focus signal indicating that a focus is formed in the vicinity;
A time measuring unit for measuring an elapsed time from the detection time of the first focus signal to the detection time of the second focus signal when the objective lens is brought close to the optical information medium by the objective lens actuator; Have
The optical pickup according to claim 1, further comprising: a determination unit that determines a type of the optical information medium based on the elapsed time.   23. The optical pickup according to claim 22, wherein the determination unit compares a reference value set in advance with the value of the elapsed time, and determines the type of the optical information medium based on the comparison result.

Images