KR100254604B1 - Optical disc discrimination method and device - Google Patents

Abstract

PURPOSE: A device for deciding an optical disk is provided to decide the disk by using different PLL(Phase Locked Loop) LOCK signal periods of a CD(Compact Disc) or a DVD(Disk Video Disc). Therefore, it is possible to remove a disk deciding error, and to correctly decide the disk. CONSTITUTION: An optical pick-up(110) is selectively set up according to a heterogeneous optical disk, and reads data. A detector(117) detects a PLL(Phase Locked Loop) LOCK signal according to a setup mode from an RF(Radio Frequency) signal detected from the optical pick-up(110). A disk decider(114) decides whether a setup mode state is in accord with the detected PLL LOCK signal. A controller(115) applies a control signal to the detector(117) according to the setup mode, and performs a controlling operation by the setup mode on the basis of a result of the disk decider(114).

Description

Optical disc discrimination method and device

The present invention relates to a method and apparatus for determining a fan disk, and more particularly, to a method and apparatus for discriminating a compact disc (hereinafter referred to as a CD) and a digital video disc (hereinafter referred to as a DVD). About

The CD, which appeared in recent years as a recording medium, has a disc thickness of 1.2 mm and a total recording capacity of about 650 Mbytes. However, this recording medium has been used in various fields, image media, sound equipment, and computer parts, and therefore, it needs more and more large capacity recording media. Therefore, even if the recording medium developed in response to this expectation is a moving picture, the DVD is an image recording medium capable of storing two hours of data. The DVD has a disk thickness of 0.6 mm, which is about 1/2 the thickness of the CD, and the total storage capacity is about 5 Gbytes.

However, before extending the use area of the DVD, the area occupied by the CD was too wide to ignore the existing CD. Therefore, when implementing a reproducing apparatus for reproducing information recorded on the DVD, making it possible to reproduce the CD has become one of important requirements.

Therefore, the disc boards have different thicknesses (meaning that the recording layers for recording information on the discs are located at different heights), and the information recorded on the two discs having different densities of recorded information is reproduced in one piece. In order to play on the device, it is first necessary to determine whether the disc seated on the turntable is a CD or a DVD. This is because the pickup apparatus for reading recorded information according to the type of disc and the operation of all the components involved in reproducing the signal must be controlled.

Fig. 1 is a block diagram showing the configuration of a fan disk reproducing apparatus according to the prior art. With reference to FIG. 1, the discriminating operation of the optical disc according to the prior art will be described in detail.

The overall configuration is explained first.

Beams emitted from the optical laser diode 1 are split into three beams through the diffraction grating 2. The beam split into three beams in the diffraction grating 2 passes through a collimator lens 4 which makes a parallel beam via a beam splitter 3. Then, an optical lens 6 passes through an object lens 5 that focuses a beam spot on a pit in which information is recorded.

Through such a path, the beam modulated by the information carrier recorded on the information recording surface of the optical disc 6 is reflected along the same path back to the objective lens, the collimating lens, and the beam splitter. The path of the beam splitter is changed to be collected by a sensor lens 7, and the focused beam is incident to an optical detector 8.

In this case, the photodetector 8 is divided into four light receiving parts A, 3, C, and D for receiving the main criminal, and is located at the center thereof, and the other light receiving parts E and F for receiving the auxiliary beams above and below the light receiving part. Located.

The electrical signal output from the photodetector 8 of the pickup apparatus 10 configured as described above is a high frequency signal processor for performing predetermined signal processing and amplification so as to be used as a basic signal for tracking and focusing control and information reproduction ( 11) is applied. The tracking and focusing control signals output from the high frequency signal processor 11 are input to the servo unit 12, and servo control is performed according to the input signals.

In addition, the information reproduction signal output from the high frequency signal processor 11 is applied to the digital signal processor 13 and the disc discriminator 14. The digital signal processing unit 13 outputs digital information by decoding error correction on the input signal, and the disc determination unit 14 compares the information reproduction signal with a reference signal to determine what optical disc is currently seated.

The output signal of the disc discrimination unit 14 is applied to the microprocessor unit 15 to control the overall system control according to the optical disc currently mounted on the turntable.

Hereinafter, the disc discrimination operation of the optical disc reproducing apparatus according to the prior art will be described in detail.

First, in order for the pickup apparatus 10 to read the information recorded on the recording medium, it must be controlled to fit the optical disc currently mounted on the turntable. In other words, the disc substrate has different thicknesses (which means that the recording layers for recording the information on the disc are located at different heights), and the information recorded on the two discs differs in the density of the recorded information. In order to read from the pickup apparatus, control must be made according to the optical disk on which the pickup apparatus is mounted.

In general, a process in which the pick-up apparatus is controlled according to an optical disc may be performed according to whether the beam spot is adjusted according to the numerical aperture of the objective lens 5 or the wavelength of the beam so that the beam spot exactly matches the recorded pit. Some process is required. However, in the present invention, only how the optical disc is discriminated in the playback apparatus is described, so the description of this part is omitted.

Therefore, in the initial operation of the system, the microprocessor unit 15 that performs system-wide control first sets the initial operation of the system by fitting the system to CD or DVD. In the present invention, it is described that the system is set to CD for the sake of understanding.

At this time, the control performed by the microprocessor unit 15 performs a control operation such that the predetermined signal processing is performed by matching the servo unit 12 and the high frequency signal processing unit 11 with the CD, and performing the operation. As a result, the servo unit 12 sets the pick-up device 10 to CD so as to set initial operation.

After the initial operation of the system as a whole is performed as described above, the signals and auxiliary beams E and F according to the main beams A, B, C, and D detected by the photodetector 8 of the pickup device 10 are applied. The signal is input to the high frequency signal processor 11.

The high frequency signal processing section 11 adds all the signals corresponding to the input main beam, and amplifies and outputs the signals A + B + C + D appropriately in accordance with the CD. At this time, the output signal is input to the digital signal processing unit 13 to correct the decoding error and output the digital information.

The signal A + B + C + D output from the high frequency signal processor 11 is input to the disc discriminator 14, and the signal is compared with a reference signal to determine what optical disc is currently mounted on the turntable. Determine. At this time, the disc discrimination by the digital discriminating unit 14 determines that the CD mode of the microprocessor unit 15 and the optical disc seated on the current turntable when the signal applied from the high frequency signal processing unit 11 is larger than the reference signal. I think it matches. When the signal applied in the high frequency signal processor 11 is smaller than the reference signal, it is determined that the CD mode initially set by the microprocessor unit 15 does not match the optical disk mounted on the current turntable.

That is, since the tracking servo is controlled according to the track pitch of the set mode, when the mode state set in the microprocessor unit 15 and the optical disk mounted on the turntable do not match, the signal read from the pickup device 10 Since the level is different from the level of the signal read out in the adjusted state, disc discrimination can be made by comparison with the reference signal.

When the disc determining unit 14 indicates that the determination signal matches the current recording medium by the above process, the microprocessor unit 15 performs a full-scale system control operation in accordance with the determined recording medium.

However, if it is determined by the above process that the signal determined by the disc determination unit 14 does not match the mode set by the current recording medium and the microprocessor unit 15, the microprocessor unit 15 restarts the system. The disk is determined by setting the initial operation of the system in accordance with the above, and performing the above-described process from the beginning again.

The electrical signals E and F of the auxiliary beams input to the high frequency signal processor 11 are calculated as difference signals EF between the two auxiliary beams, and are applied to the servo unit 12 to be used as tracking control signals. do.

In addition, the electrical signals (A, B, C, D) for the main culprit are calculated as (A + B)-(B + D), and signal amplification by a predetermined amount is applied to the servo unit 12 to provide information. It is used as a focusing control signal for whether the pickup device is accurately focusing on the recorded pit.

As described above, the determination of the optical disc in the conventional optical disc reproducing apparatus is performed by comparing the high frequency signal detected by the optical pickup apparatus 10 with the reference signal to determine the level of the detected signal. That is, when the signal level detected from the optical pickup device 10 becomes smaller than the reference signal level, the microprocessor unit 15 determines that there is an error in the optical disc setting mode.

However, the conventional disc discrimination has a problem in that the difference between the signal level detected from the optical pickup device 10 and the reference signal level is not clearly distinguished due to the scratches or noises present in the optical disc. In other words, the CD and the DVD have different tracking and focusing adjustment states because the thickness of the recording layer of the disc and the interval between tracks on which data is recorded are different. However, if there is a scratch on the track on which the information is recorded, the pickup apparatus will leave the track on which the information is recorded and thus cannot perform the normal playback operation, thus causing an error in disc determination.

Accordingly, an object of the present invention is to provide an optical disc determination method and apparatus capable of accurately determining which optical disc is mounted on a turntable in an apparatus for reproducing one or more optical discs.

1 is a block diagram showing the structure of a conventional optical disc discrimination apparatus.

2 is a block diagram showing the configuration of an optical disc discrimination apparatus according to the present invention.

3 is an operation flowchart for discriminating an optical disk according to Embodiment 1 of the present invention.

4 is an operation flowchart for discriminating an optical disk according to Embodiment 2 of the present invention.

5 is an operation flowchart for discriminating an optical disk according to Embodiment 3 of the present invention.

6 is an operation flowchart for discriminating an optical disk according to Embodiment 4 of the present invention.

* Explanation of symbols for main parts of the drawings

10,110: pickup device 1l, 111: high frequency signal processing unit

12,112: Servo unit 13,113: Digital signal processing unit

14,114: disc discrimination unit 6,106: optical disc

15,115: microprocessor unit 117: PLL LOCK signal detector

An optical disc discrimination method of the present invention for achieving the above object comprises: a first step of setting a system in an arbitrary mode; A second step of detecting a PLL LOCK signal according to the mode set in the first step; A third step of determining whether or not the set mode state is matched according to whether the PLL LOCK signal is detected in the second step; And a fourth step of setting a mode and performing optical disc reproduction based on the determination in the third step.

An optical disc discriminating apparatus of the present invention for achieving the above object comprises: optical pickup means for selectively setting data according to heterogeneous optical discs to read data; Detection means for detecting a PLL LOCK signal according to a setting mode from a high frequency signal detected by the optical pickup means; Disc discrimination means for determining whether or not the set mode state coincides in accordance with the presence or absence of a PLL LOCK signal detected by the detecting means; And control means for applying a control signal according to the set mode to the detecting means, and performing control according to the mode set based on the determination of the disc discriminating means.

The optical disc discrimination method and apparatus of the present invention is characterized by setting the playback apparatus in an arbitrary mode and determining whether the optical disc mounted on the turntable is a CD or a DVD by detecting the PLL LOCK signal.

The optical disc discrimination method and apparatus of the present invention is characterized by performing a playback operation when the PLL LOCK signal is detected from the set mode, and checking whether the PLL LOCK signal is detected again during the playback operation.

Hereinafter, an optical disc discrimination method and apparatus of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing the configuration of an optical disc discrimination apparatus according to the present invention.

Examine the configuration. An optical disc 106, a motor driven for rotation of the optical disc 106, and an optical pickup device 110 for reading data recorded on the optical disc 106 are included.

The electrical signal output from the photodetector (not shown) of the optical pickup device 110 performs a predetermined signal processing and amplification so as to be used as a basic signal for tracking and focusing control and information reproduction ( 111).

The tracking and focusing control signal output from the high frequency signal processor 111 is input to the servo unit 112, and servo control is performed according to the input signal.

In addition, the information reproduction signal output from the high frequency signal processor 111 is applied to the digital signal processor 113 and the PLL LOCK signal detector 117. The digital signal processor 113 outputs digital information by decoding error correcting an input signal, and the PLL LOCK signal detector 117 detects a PLL LOCK signal from the input high frequency signal.

The PLL LOCK signal detection unit 117 detects the PLL LOCK signal by a general PLL LOCK detection device. In brief, the high frequency signal processing unit 111 outputs the reference clock signal according to the motor rotation speed in a set mode. This is done by detecting whether the high frequency signal is synchronized.

When the PLL LOCK signal detection unit 117 detects a PLL LOCK signal, a signal according to the detection is input to the disc determination unit 114, and the disc determination unit 114 is output from the PLL LOCK signal detection unit 117. Disc determination is made by the signal. That is, when the PLL LOCK signal is detected and retracted from the high frequency signal input from the PLL LOCK signal detection unit 117, it is determined that the adjustment is correctly performed according to the disc discrimination. If the PLL LOCK signal detection unit 117 determines that the PLL LOCK signal If the detection is not made, it is determined that the adjustment according to the disc determination is made incorrectly.

In this process, the disc determination signal output from the disc discrimination unit 114 is applied to the microprocessor unit 115, and the microprocessor unit 115 transmits the high frequency signal processor 111 and the disc determination signal according to the input disc determination signal. The control of the servo unit 112 is performed.

Next, the optical disc discrimination operation of the present invention by the above configuration will be described in detail.

3 is an operation flowchart for discriminating the optical disk according to the first embodiment of the present invention.

After mounting the optical disc 106 on a turntable (not shown) and applying power, the microprocessor unit 115 that performs system-wide control first sets the initial operation of the system to match the system to CF or DVD. . In the present invention, it is described that the system is set to CD for the sake of understanding.

At this time, the control performed by the microprocessor unit 115 performs a control operation such that a predetermined signal processing is performed by matching the servo unit 112 and the high frequency signal processing unit 111 with a CD. By doing so, the servo unit 112 sets an initial operation in accordance with the CD mode of tracking and focusing of the pickup device 110 (step 201).

In addition, the microprocessor 115 applies a control signal for setting the CD mode to the PLL LOCK signal detection unit 117. The PLL LOCK signal detection unit 117 sets the reference clock signal as a signal corresponding to the CD by this control signal.

After adjusting tracking and focusing of the pickup apparatus 110 to the CD mode as described above, focusing of the optical pickup apparatus 110 is performed by turning on the focusing servo (step 202).

After the focus adjustment of the optical pickup friend 110 is performed in step 202, the microprocessor unit 115 applies a control signal for rotating the optical disc 106 to the servo unit 112 (step 203). . In step 203, the reference clock signal for rotating the optical disc applied from the servo unit 112 to the motor is applied based on the CD mode set in step 201.

In general, the rotational speed of the motor for rotating the CD is 500 rpm in the inner circumference of the disk and 200 rpm in the outer circumference of the disk. The rotation speed of the motor for rotating the DVD is 1400 rpm in the inner circumference of the disc and 600 to 700 rpm in the outer circumference of the disc. Therefore, the rotation speed of the CD is about four times slower than the rotation speed of the DVD, and the rotation click signal of the applied motor becomes four times the clock signal period applied to rotate the DVD.

In step 203, the optical disc 106 is rotated, and then the microprocessor unit 115 applies a tracking off signal to the servo unit 112 (step 204). The application of the tracking off signal is for determining the type of the optical disc mounted on the turntable of the current operation, and thus is intended to derive only the minimum operation of the optical pickup apparatus 110.

The optical disk 106 is rotated at the rotational speed of the CD mode by the above operation process, and the tracking and focusing of the optical pickup device 110 is adjusted according to the CD mode. The minimum operating state for reading out a signal from the optical disc 106 is achieved.

At this time, the optical signal detected from the photodetector (see FIG. 1) of the optical pickup device 110 is converted into an electrical signal and outputted, and the signal is input to the high frequency signal processing unit 111 to signal such as amplification and phase adjustment. Processing is done and output.

On the other hand, the length of the pit in which information is recorded on the track of the optical disc 106 is 3T-11T of the reference clock period T in accordance with the rotational speed of the optical disc 106. Therefore, when the optical disc mode state (current CD mode) set by the system and the disc mounted on the turntable match, the high frequency signal read out from the optical pickup device 110 is within 3T to 11T of the rotation clock period. It should consist of a signal of.

In other words, during the rotation operation of the optical disc 106, the high frequency signal detected by the optical pickup device 110 is brought from the signal synchronized with 3T of the rotation clock period of the CD to the signal synchronized with 11T.

In this way, the reproduction high frequency signal output from the high frequency signal processor 111 is applied to the PLL LOCK signal detector 117. The PLL LOCK signal detection unit 117 detects the longest 11T high frequency signal without fear of being deformed by scratches or noise present on the disk for a predetermined period. In other words, a pit having a length of 11T, which is the longest pit existing on the track of the optical disc, is always detected at regular intervals when the set optical disc mode matches the seated optical disc, so that the PLL LOCK signal detection unit 117 ) Sets 11T of the clock clock cycle of the CD as a synchronization signal, and checks whether a PLL LOCK signal generated when a continuous detection signal detecting the 11T synchronization signal in the input high frequency signal falls within the PLL range ( Step 205).

When the PLL LOCK signal is detected by the step 205, the disk determination unit 114 determines that the disk mode currently set in the system is correct, and applies the signal according to the microprocessor unit 115, and the micro The processor unit 115 performs control for the reproducing operation in the current state (step 206).

However, if the PLL LOCK signal is not detected in step 205, the disc discrimination unit 114 determines that the disc currently seated is not a CD but a DVD and applies the signal to the microprocessor unit 115 (step 208). ).

The microprocessor unit 115 switches the control state of the system to the DVD mode determined by the disc determination unit 114, and thereafter, the reproduction high frequency signal read out by the optical pickup apparatus 110 is a high frequency signal processing unit ( The digital signal processor 113 is supplied to the digital signal processor 113 to perform reproduction after predetermined signal processing (step 207).

As described above, in the optical disc discrimination method according to the first embodiment of the present invention, each state of the system is set to an arbitrary mode, and the PLL LOCK signal according to the mode set in the reproduction high frequency signal output from the optical pickup apparatus 110 is provided. Is detected, and the disc discrimination operation is performed according to the determination.

Therefore, in the present invention, disc discrimination is performed by using a significantly different PLL LOCK signal cycle of a CD or DVD. Thus, a disc that has been generated due to scratches or eccentricity during disc discrimination operation due to a level difference of a playback signal as in the prior art There is an effect that the discriminant error can be eliminated and the disc judgment can be made accurately.

4 is a flowchart showing a method of discriminating an optical disc according to a second embodiment of the present invention.

In the second embodiment, after the PLL LOCK signal detection determination of the first embodiment (step 205 in FIG. 3), when the PLL LOCK signal is not detected, the system state is initialized to the DVD mode, and the PLL LOCK signal detection process is performed again. Do this.

In more detail, when the PLL LOCK signal is detected in the CD-initialized state (step 305), the currently loaded disc is determined to be a CD to continuously perform a playback operation (step 306, step 313). However, if the PLL LOCK signal is not detected in the CD initialization state, the microprocessor unit 115 switches the control state of the servo unit 112 and the high frequency signal processing unit 111 to the DVD mode (step 307).

Then, the focusing servo is turned on (step 308), and the disk 106 is rotated by applying a control signal to the motor. In this case, since the clock signal applied to the rotational speed of the DVD is applied to the motor from the servo unit 112, the clock signal of the CD has a quarter period (step 309), and the rotational speed of the optical disc is It's faster than a CD. The tracking servo is turned off (step 310).

In the above process, the optical disc 106 is rotated at the rotational speed of the DVD. The optical pickup device 110 is controlled to the DVD mode and reads the signal recorded on the optical disc 106. That is, when the optical disc 107 is a DVD, the reproduction signal output from the optical pickup device 110 is synchronized with 3T to 14T of the rotation clock period T of the DVD.

The signal read from the optical pickup device 110 is input to the PLL LOCK signal detector 117 after predetermined signal processing by the high frequency signal processor 111. The PLL LOCK signal detection unit 117 sets 14T of the rotation clock period of the DVD as a synchronization signal and checks whether a signal synchronized with the 14T is detected in the high frequency signal output from the high frequency signal processing unit 111 (the Step 311).

At this time, the PLL LOCK signal detection process is performed as in the case of the CD, but in the case of DVD it detects a signal ranging from 3T to 14T. From the detected signal, the longest 14T signal is set as a synchronous signal, and if a continuous detection signal that detects a signal synchronized with 14T from the input high frequency signal is within the PLL range, whether the PLL LOCK signal generated is detected. Check it.

The PLL LOCK signal detection unit 117 described above uses a general PLL LOCK detection device and is configured to be converted into a reference click signal of a CD or DVD by a signal applied from a control means such as the microprocessor unit 115. do.

In other words, the detection of the PLL LOCK signal according to the above-described step 311 is performed by detecting the initializing of the system in the DVD mode. Therefore, if the PLL LOCK signal is detected in this step, the disc determination unit 114 will determine the disc currently seated on the turntable as a DVD (step 312).

However, if the PLL LOCK signal is not detected even in this process, that is, if the PLL LOCK is detected first in step 305 while the CD mode is initialized, then the system is moved to the DVD mode in step 311. When the PLL LOCK signal is not detected even after the conversion, the disc discrimination unit 114 determines that the seated disc of the current turntable is a non-playable disc (step 314).

That is, in the disc discrimination method according to the second embodiment of the present invention, first, the system is initialized in a specific mode and the PLL LOCK signal is detected accordingly. LOCK signal detection is performed to ensure accurate disc determination.

Therefore, the disc discrimination according to the second embodiment of the present invention has an effect of determining the non-playable disc on the turntable before performing the play operation.

The following describes a disc discrimination method according to Embodiment 3 of the present invention shown in FIG.

As shown in FIG. 5, after the PLL LOCK signal is detected in the state of initializing the system in a specific mode as shown in FIG. 4 (FIG. 4 is 305 or 311, and FIG. 5). In step 405 or step 411, it is recognized that the mode currently set in the system and the optical disk seated on the turntable (step 4 in step 305 or step 312, in step 5 in step 406 or Step 412).

When the playback operation is performed in the currently set mode (step 313 in FIG. 4 and step 413 in FIG. 5), the PLL LOCK signal is detected again (step 415 in FIG. 5). At this time, when the PLL LOCK signal is detected in step 415, if the mode set in the current system is a CD, the reference clock signal according to the rotation clock cycle of the CD is input to the PLL LOCK detection unit 117, and the currently set mode is DVD. In one case, the reference clock signal corresponding to the rotation clock cycle of the DVD is input to the PLL lock detection unit 117.

In the above process, that is, if the PLL LOCK signal is detected in the step 415, playback is continued in the currently set mode (steps 415 and 417), and if the PLL LOCK signal is not detected, the mode set in the system In operation 418, the control unit 100 switches to and performs a playback operation.

In other words, the optical disc discrimination according to the third embodiment of the present invention is to perform PLL lock detection once more when the reproduction operation is performed after one PLL lock detection is performed. Therefore, a more accurate disc determination operation is achieved.

6 is a flowchart of an optical disc discrimination operation according to Embodiment 4 of the present invention.

In the third embodiment of the present invention, when PLL LOCK detection is performed after the reproducing operation in Fig. 5 and no PLL LOCK signal is detected, the mode is switched and regeneration is performed.

However, in the fourth embodiment, the PLL LOCK signal is detected again (step 519) when the regeneration operation is performed after the mode change (step 517 and step 518).

If the PLL LOCK signal is detected in step 519, it is determined that the disc is determined correctly (step 520). If the PLL lock is not detected, it is determined that the disc cannot be played (step 522).

As described above, the optical disc discrimination method of the present invention performs disc discrimination by using different PLL LOCK signal cycles of a CD or DVD. The disk discrimination error caused by the effect is eliminated, and the disk judgment can be made accurately.

Claims (4)

Optical pickup means for selectively setting data according to heterogeneous optical disks and reading data; Detection means for detecting a PLL LOCK signal according to a setting mode from a high frequency signal detected by the optical pickup means; Disc discriminating means for determining whether or not the set mode state coincides in accordance with the detection of the PLL LOCK signal in the detecting means; And control means for applying a control signal according to the set mode to the detecting means, and performing control according to the mode set based on the determination of the disc discriminating means. A first step of setting the system to an arbitrary mode; a second step of detecting a PLL LOCK signal according to the mode set in the first step; A third step of determining whether or not the set mode state is matched according to whether the PLL LOCK signal is detected in the second step; And a fourth step of setting a mode based on the determination in said third step and performing optical disc reproduction. 3. The method of claim 2, wherein in the third step, when the set load state is matched, the mode state is switched and the PLL LOCK signal is detected once more in the switched load. The optical disc discrimination method according to claim 2 or 3, wherein after the fourth step of reproducing the optical disc in the determined mode, the PLL LOCK signal is detected.

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