JP2007035142A - Device and method for recording/playing back optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a reduction in quality of a reproduced RF signal even in places where physical abnormalities such as flaws or fingerprints are present in an optical disk. <P>SOLUTION: Upon detection of the physical abnormalities of an optical disk 1 by a system control unit 8 based on the change of the signal level of a reproduced RF signal from, e.g., a peak bottom detection circuit 10, when the operation of recording/reproducing information in the places of the physical abnormalities is carried out, a signal for raising emitted laser power from an optical pickup 5 is output to an optical power control unit 14, and a signal for switching focus and tracking servos to held states is output to a servo circuit 4. If the held states continue more than predetermined fixed time and/or if the signal level of the reproduced RF signal drops below a predetermined fixed threshold value indicating a focused state during the continued recording/reproducing operation in the places of the physical abnormalities, the servo held states are returned to servo-ON states. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc recording / reproducing apparatus and an optical disc recording / reproducing method, and in particular, a recording / reproducing operation can be performed at an appropriate signal level even in a place where a physical abnormal state such as a scratch or a fingerprint exists on the optical disc. The present invention relates to an optical disc recording / reproducing apparatus and an optical disc recording / reproducing method.

In recent years, optical disks such as CDs (Compact Disks), DVDs (Digital Versatile Disks), and next-generation DVDs have become mainstream as information recording media. In order to perform a recording / reproducing operation on a recording medium with an optimum optical power at the time of recording / reproducing information on such an optical disc, an optical pickup (OPU: Optical) is provided on the optical disc.
OPC (Optical) that detects the optimal optical power of the laser light emitted from the Pickup Unit, taking into account factors such as the type of optical disk, recording and playback speed, and characteristics of the laser diode
(Power Control) operation is executed in advance, and the laser power emitted from the optical pickup used for actual information recording / reproduction is set to the optimum optical power detected by the OPC operation. Control is performed so that the information is recorded and reproduced under optimum conditions. The OPC operation refers to test data using laser light whose optical power is changed stepwise in a specific area on the optical disk or in the vicinity of the original information recording area before the original information recording / reproducing operation. The optimum optical power level is obtained by recording / reproducing.

However, if there are physical abnormal conditions such as scratches, fingerprints, warpage, surface shake, and pigment unevenness on the optical disk, even if recording / reproducing operation is performed with the optimal optical power, It becomes impossible to record and reproduce information.
In addition, if there are physical abnormal conditions such as scratches or fingerprints on the optical disk, the servo that performs focus control or tracking control may be disconnected during the recording / reproducing operation. It will fall into a state that can not be.

  As a conventional optical disc recording / reproduction control method for preventing such a situation, as shown in Japanese Patent Application Laid-Open No. 2002-319135 “Optical Disc Recording Method” shown in Patent Document 1, it is optimal prior to the actual recording operation. In a test recording operation executed for grasping various recording conditions, if scratches, fingerprints, etc. are detected on the optical disk surface, the laser power emitted from the OPU (optical pickup) to the optical disk surface is changed and the focus is changed. A recording method that attempts to acquire a situation that is not affected by a physical abnormal state on the optical disk by setting the servo and tracking servo in the hold state is used.

  FIG. 4 is a block diagram showing a block configuration of a conventional optical disc recording / reproducing apparatus, and shows a configuration of the disc recording / reproducing apparatus described in Patent Document 1. In FIG. An optical disk recording / reproducing apparatus 200 includes a spindle motor 2, a frequency generator 3, a servo circuit 4, an optical pickup (OPU) 5, an RF amplifier 6, and an address detection circuit for recording / reproducing information on / from an optical disk 1 as a recording medium. 7, a system control unit 8A, a decoder 9, a peak / bottom detection circuit 10, an encoder 11, a strategy circuit 12, a laser driver 13, and an optical power control unit 14.

  In the optical disk recording / reproducing apparatus 200, the optical disk 1 is rotationally driven by a spindle motor (SPM) 2, and a frequency generator (FG) 3 composed of, for example, a Hall element is connected to the rotation shaft. The FG pulse output from 3 is input to the servo circuit 4. Further, in order to record information at a constant linear density along the track of the information recording area of the optical disc 1, a wobble (Wobble) including an ATIP (Absolute Time In Pregroove) time code indicating an absolute time is used as a recording linear density control signal. ) The signal is superimposed and recorded.

The optical disk 1 is a CAV (Constant Angular
When controlling (Velocity: constant rotation speed), the servo circuit 4 rotates the spindle motor 2 in accordance with the servo control signal from the system control unit (CPU) 8A so that the FG pulse and the reference clock are synchronized. Control. As a result, the rotation of the optical disc 1 is controlled at a constant rotation speed.

On the other hand, the optical disk 1 is a CLV (Constant Linear).
When controlling the velocity (constant linear velocity), the servo circuit 4 is read from the optical disc 1 via the optical pickup (OPU) 5 in response to a servo control signal from the system control unit (CPU) 8A, The spindle motor 2 is rotationally controlled so that the wobble signal amplified by the RF amplifier 6 is synchronized with the reference clock. Thereby, the optical disc 1 is controlled to rotate at a constant linear velocity.

  Further, the wobble signal output from the RF amplifier 6 is supplied to the address detection circuit 7, where the ATIP time code and the ATIP clock are extracted, and the address of the optical disc 1 is detected. The detected address is supplied to the system control unit 8A. The system control unit 8A recognizes the recording position in the radial direction of the optical disk 1 from the input address, and outputs a reference clock variably set based on the recording position to the servo circuit 4 including the servo control signal. To do.

Also, a reproduction RF (Read Frequency) signal that is an output of the RF amplifier 6 is input to the decoder 9 where it is decoded and EFM (Eight
to Fourteen Modulation (CR) demodulation and CIRC (Cross Interleaved Reed-Solomon Code) decoding, and output to the outside as playback data. In the decoding process, CI errors and synchronization signals are detected and supplied to the system controller 8A. The

  Further, the reproduction RF signal output from the RF amplifier 6 is also supplied to the peak / bottom detection circuit 10. The peak / bottom detection circuit 10 detects the peak value and bottom value of the reproduction RF signal, and based on this, the reflectivity, reproduction RF signal amplitude, modulation degree (Modulation), asymmetry β, etc. of the optical disc 1 are detected. These detection results are supplied to the system control unit 8A.

  The reproduction RF signal output from the RF amplifier 6 not only detects the peak value and bottom value of the reproduction RF signal, but also supplies it to an envelope detection circuit and a jitter / deviation detection circuit to reproduce the reproduction RF signal. It is also possible to detect the envelope (envelope), jitter, deviation, etc., and supply them to the system controller 8A.

  These CI error, synchronization signal, reflectance, reproduction RF signal amplitude, modulation degree, asymmetry β, jitter, deviation, etc. supplied to the system control unit 8A are parameters indicating the quality of the reproduction RF signal, and are recorded and reproduced. In operation, the information is processed by the system control unit 8A as information for controlling the power level of the laser light emitted from the optical pickup (OPU) 5 to the optical disc 1 and controlling the servo operation of the focus servo and track servo. .

  On the other hand, recording data supplied from the outside as data for recording on the optical disc 1 is input to the encoder 11, and the recording data is CIRC / EFM encoded in accordance with the EFM clock from the system control unit 8A. Thereafter, based on the CIRC / EFM encoded recording data, the strategy circuit 12 generates a recording pulse in a format suitable for recording, and supplies it to the laser driver 13. The laser driver 13 generates a drive signal for driving the optical pickup 5 and supplies it to the optical pickup 5. As a result, the optical pickup 5 emits a laser beam having an output power corresponding to the drive signal level to the optical disc 1 to form recording pits having a linear density based on the EFM clock on the optical disc 1.

  Here, prior to the recording / reproducing operation of information on the optical disc 1, the system control unit 8A previously executes an OPC (Optical Power Control) operation for detecting the optimum optical power, and the recording / reproducing speed−optimum power. Acquired as a characteristic. The system control unit 8A refers to the recording / reproduction speed-optimal power characteristic acquired in advance by the OPC operation according to the parameter indicating the quality of the reproduction RF signal supplied at the time of the recording / reproduction operation. The laser driver 13 is controlled via the control unit 14. As a result, the optical pickup 5 is irradiated with the laser light with the optimized optical power by the drive signal from the laser driver 13, and information can be appropriately recorded on and reproduced from the optical disk 1.

  Next, the recording / reproducing operation of the optical disc recording / reproducing apparatus 200 when there are physical abnormal states such as scratches, fingerprints, warpage, surface shake, and pigment unevenness on the optical disc 1 will be described. FIG. 5 is an operation flowchart for explaining a recording / reproducing operation in the conventional optical disc recording / reproducing apparatus. Recording / reproducing when a scratch, a fingerprint or the like is detected on the optical disc 1 in the optical disc recording / reproducing apparatus 200 shown in FIG. The operation is described.

  If a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, the peak level and the bottom level of the reproduced RF signal at that location change greatly. When the system controller 8A does not detect a large change in the peak level or bottom level of the reproduction RF signal supplied from the peak / bottom detection circuit 10 (NO in step S11), the system controller 8A physically Assuming that no abnormal state exists, the recording / reproducing operation using the optimum optical power acquired in advance by the OPC operation is continued. On the other hand, when a large change is detected (YES in step S11), it is detected that a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1.

  In such a case where a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, the system control unit 8A determines whether the optical pickup (OPU) is in accordance with the magnitude of the change in peak level or bottom level. ) The signal level of the drive signal from the laser driver 13 to the optical pickup (OPU) 5 is increased by generating a power control signal for the optical power control unit 14 so as to increase the optical power emitted from 5. Laser light is emitted from the optical pickup (OPU) 5 onto the optical disc 1 (step S12).

  Further, when a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, the focus servo state or the tracking servo state may be greatly deviated. In order to prevent this, the system control unit 8A outputs the focus servo hold and tracking servo hold signals as servo control signals to the servo circuit 4 as long as physical abnormal states such as scratches and fingerprints continue (step S13). As a result, the servo circuit 4 maintains the state of maintaining the focus servo state and the tracking servo state so far, and can continue the information recording / reproducing operation at the normal position.

JP 2002-319135 A (page 3-5, FIG. 1)

  As described above, when a physical abnormal state such as a scratch or a fingerprint on the optical disk is detected, the laser power from the optical pickup (OPU) is increased, and the focus servo and tracking servo are maintained in the hold state. Even if the emission laser power can be increased to an appropriate level, the servo hold time becomes longer depending on the size of the physical abnormal state such as scratches and fingerprints on the optical disk, and the scratches and fingerprints It is fully conceivable that the reproduction RF signal level is lowered during the recording / reproducing operation at the location where the physical abnormal state exists.

  That is, if the focus state or tracking state is fixed while the servo is held for a long time, for example, the focus is greatly deviated from the focused state on the optical disk surface. Even if the laser power is increased to increase the signal level of the reproduced RF signal that has decreased due to a physical abnormal state such as a scratch or a fingerprint, the signal level of the reproduced RF signal is greatly reduced because it is significantly out of focus. There is a problem that it cannot be increased to a level at which a normal recording / reproducing operation can be obtained.

  In other words, even if it tries to cover the signal level of the reproduced RF signal that has been reduced due to physical abnormalities such as scratches or fingerprints on the optical disk by powering up the laser beam emitted from the optical pickup, it can be used as a focus servo or tracking servo. As a result of maintaining the hold state longer than necessary, the focus state is greatly deviated, the signal level of the reproduction RF signal is lowered, and there is a disadvantage that the normal recording / reproduction operation cannot be restored forever. .

  Accordingly, an object of the present invention is to prevent a decrease in the signal level of the reproduction RF signal during the recording / reproducing operation even when the presence of a physical abnormal state such as a scratch or a fingerprint is detected on the optical disc, It is an object of the present invention to provide an optical disc recording / reproducing apparatus and an optical disc recording / reproducing method capable of ensuring a sufficient signal level.

  In order to solve the above-described problems, an optical disc recording / reproducing apparatus and an optical disc recording / reproducing method according to the present invention employ the following characteristic configuration.

(1) In an optical disc recording / reproducing apparatus for recording / reproducing information on / from an optical disc, when it is detected that there is a physical abnormal state represented by a scratch or a fingerprint on the optical disc, the location of the physical abnormal state When performing information recording / reproducing operation, the emission laser power from the optical pickup is increased and the focus servo and tracking servo are held in order to compensate for the decrease in the level of the reproduction RF signal based on the physical abnormal state. On the other hand, when the continuation of the hold state exceeds a predetermined time during the recording / reproducing operation to the location where the physical abnormal state exists, the focus servo and tracking servo are switched from the hold state to the servo-on state. An optical disk recording / reproducing apparatus to be restored to
(2) In an optical disc recording / reproducing apparatus for recording / reproducing information on / from an optical disc, when it is detected that there is a physical abnormal state represented by a scratch or a fingerprint on the optical disc, the location of the physical abnormal state When performing information recording / reproducing operation, the emission laser power from the optical pickup is increased and the focus servo and tracking servo are held in order to compensate for the decrease in the level of the reproduction RF signal based on the physical abnormal state. On the other hand, if the amplitude level, peak level, or bottom level of the reproduction RF signal falls below a predetermined threshold during the recording / reproduction operation to the location where the physical abnormal state exists, the focus servo And an optical disk recording / reproducing apparatus for returning the tracking servo from the hold state to the servo-on state.
(3) In an optical disc recording / reproducing apparatus that records and reproduces information on an optical disc, when it is detected that there is a physical abnormal state represented by a scratch or a fingerprint on the optical disc, the location of the physical abnormal state When performing information recording / reproducing operation, the emission laser power from the optical pickup is increased and the focus servo and tracking servo are held in order to compensate for the decrease in the level of the reproduction RF signal based on the physical abnormal state. While the recording / reproducing operation to the location where the physical abnormal state exists is continued, the continuation of the hold state exceeds a predetermined time, and the amplitude level or peak level or bottom of the reproduced RF signal When the level falls below a predetermined threshold value, focus servo and tracking servo are supported from the hold state. Optical disc recording and reproducing apparatus is returned to the vowel state.
(4) As means for detecting the location of the physical abnormal state on the optical disc, the amplitude level or peak level or bottom level variation of the reproduction RF signal, the reflectance variation amount, the focus error signal or the tracking error signal The optical disc recording / reproducing apparatus according to any one of (1) to (3), wherein any one or more of the change amounts are used.
(5) In an optical disc recording / reproducing method for recording / reproducing information on / from an optical disc, when it is detected that there is a physical abnormal state represented by a scratch or a fingerprint on the optical disc, the location of the physical abnormal state When performing information recording / reproducing operation, the emission laser power from the optical pickup is increased and the focus servo and tracking servo are held in order to compensate for the decrease in the level of the reproduction RF signal based on the physical abnormal state. On the other hand, when the continuation of the hold state exceeds a predetermined time during the recording / reproducing operation to the location where the physical abnormal state exists, and / or the amplitude level of the reproduced RF signal or If the peak level or bottom level falls below a predetermined threshold, the focus servo and tracking servo are Optical disc recording and reproducing method of returning to the servo-on state from the state.
(6) As a method for detecting the location of the physical abnormal state on the optical disc, the amplitude level or peak level or bottom level variation of the reproduction RF signal, the reflectance variation amount, the focus error signal or the tracking error signal (5) The optical disc recording / reproducing method of (5), wherein any one or more of the change amounts are used.

  According to the optical disc recording / reproducing apparatus and the optical disc recording / reproducing method of the present invention, when a decrease in the level of the reproduction RF signal from the optical disc is detected due to a physical abnormal state such as a scratch or a fingerprint on the optical disc, information recording operation or reproduction is performed. In operation, by raising the emission laser power of the optical pickup in accordance with the level reduction of the reproduction RF signal and setting the servo hold state, not only the level reduction of the reproduction RF signal can be prevented, but also The following effects can be obtained.

  In other words, when the hold time of the focus servo and tracking servo elapses for a predetermined time and / or when the signal level of the reproduction RF signal falls below a predetermined threshold value to indicate the in-focus state, the servo Even if it is a case where the existence range of physical abnormal states such as scratches and fingerprints on the optical disc is large and continues for a long time by releasing the hold state of The servo state is set to on and controlled so that the in-focus state is maintained normally, and the level of the reproduced RF signal is reliably lowered even during recording / reproducing operations in the presence range of physical abnormal states such as scratches and fingerprints. Therefore, it is possible to ensure an appropriate signal level, and to prevent deterioration in the quality of the reproduction RF signal.

  Hereinafter, preferred embodiments of an optical disc recording / reproducing apparatus and an optical disc recording / reproducing method according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing an example of a block structure of an optical disc recording / reproducing apparatus according to the present invention.

  In the embodiment of the optical disc recording / reproducing apparatus 100 shown in FIG. 1, the configuration similar to that of the conventional optical disc recording / reproducing apparatus 200 shown in FIG. Circuit blocks having the same function are denoted by the same reference numerals. That is, the optical disc recording / reproducing apparatus 100 in the present embodiment performs recording / reproduction of information on / from the optical disc 1 that is a recording medium, in order to perform spindle motor 2, frequency generator 3, servo circuit 4, optical pickup (OPU) 5, RF At least an amplifier 6, an address detection circuit 7, a system control unit 8, a decoder 9, a peak / bottom detection circuit 10, an encoder 11, a strategy circuit 12, a laser driver 13, and an optical power control unit 14 are provided. Furthermore, an envelope detection circuit, a jitter detection circuit, a deviation detection circuit, and the like may be further provided to detect the envelope, jitter, deviation, and the like of the reproduction RF signal.

  In the information recording / reproducing operation in the optical disc recording / reproducing apparatus 100 shown in FIG. 1, the detailed description of the same part as the operation in the optical disc recording / reproducing apparatus 200 shown in FIG. This is substantially the same as the above description in 200, and is as follows.

  The optical disc 1 mounted on the optical disc recording / reproducing apparatus 100 is driven to rotate at a predetermined rotational speed by a spindle motor (SPM) 2. A frequency generator (FG) 3 is connected to the rotation shaft of the spindle motor (SPM) 2, and an FG pulse output from the frequency generator 3 is input to the servo circuit 4. When the optical disk 1 is controlled by CAV (Constant Angular Velocity), the servo circuit 4 is controlled by the servo control signal from the system control unit (CPU) 8 so that the FG pulse and the reference clock are synchronized. The spindle motor 2 is rotationally controlled.

On the other hand, in order to record information at a constant linear density along the track of the information recording area of the optical disc 1, for example, an ATIP (Absolute Time In Pregroove) time code that is absolute time information is included as a recording linear density control signal. A wobble signal is superimposed and recorded, and the optical disk 1 is inserted into a CLV (Constant
In the case of controlling (linear velocity: constant linear velocity), the system controller 8 controls the wobble signal read from the optical disc 1 through the optical pickup 5 and amplified by the RF amplifier 6 so as to synchronize with the reference clock. The servo circuit 4 controls the rotation of the spindle motor 2 according to the servo control signal from.

  The wobble signal from the RF amplifier 6 is also supplied to the address detection circuit 7, where the address of the optical disc 1 is detected by the extracted ATIP time code and ATIP clock, and is supplied to the system control unit 8. The The system control unit 8 recognizes the recording position in the radial direction of the optical disc 1 from the input address, and outputs a reference clock variably set based on the recording position to the servo circuit 4 including the servo control signal. To do.

The reproduced RF signal, which is the output of the RF amplifier 6, is input to the decoder 9, where it is decoded, EFM (Eight to Fourteen Modulation) demodulation, and CIRC (Cross Interleaved Reed-Solomon).
Code) decoding is performed and output as reproduction data to the outside. In the decoding process, a CI error and a synchronization signal are detected and supplied to the system control unit 8.

  Further, the reproduction RF signal output from the RF amplifier 6 is also supplied to the peak / bottom detection circuit 10 to detect the peak level and the bottom level of the reproduction RF signal. Based on the detection result, the reflectance of the optical disc 1, the reproduction RF signal amplitude, the modulation degree (Modulation), the asymmetry β and the like are further detected, and these detection results are supplied to the system control unit 8.

  The reproduction RF signal output from the RF amplifier 6 not only detects the peak value and bottom value of the reproduction RF signal, but also supplies it to an envelope detection circuit, a jitter detection circuit, and a deviation detection circuit for reproduction. It is also possible to detect the envelope (envelope), jitter, deviation, etc. of the RF signal and supply it to the system control unit 8.

  These CI errors, synchronization signals, playback RF signal peak level and bottom level, playback RF signal amplitude level, reflectivity, modulation factor, asymmetry β, jitter, deviation, etc. supplied to the system control unit 8 are reproduced. This is a parameter indicating the quality of the RF signal, which is processed by the system control unit 8 to control the optical power level of the laser beam emitted from the optical pickup (OPU) 5 to the optical disc 1 in the recording / reproducing operation. A power control signal for the power control unit 14 is generated, or a servo control signal for the servo circuit 4 is generated to control the servo operation of the focus servo or the track servo.

  By receiving such a power control signal from the system control unit 8, the optical power control unit 14 controls the level of the drive signal of the laser driver 13 and emits light from the optical pickup (OPU) 5 to the optical disc 1. Control the power level to the optimum level. In addition, the servo circuit 4 that has received such a servo control signal from the system control unit 8 can perform appropriate servo control by setting the focus servo state or tracking servo state to the hold state or turning it on. I have to.

  On the other hand, recording data supplied from the outside as data for recording on the optical disc 1 is input to the encoder 11, and after the recording data is CIRC / EFM encoded according to the EFM clock from the system control unit 8, the strategy circuit At 12, a recording pulse having a format suitable for recording on the optical disk 1 is generated and supplied to the laser driver 13. In the laser driver 13, a drive signal corresponding to the recording pulse is generated and supplied to the optical pickup 5, so that a laser beam having an output power corresponding to the drive signal level is emitted to the optical disc 1, and is output onto the optical disc 1. Recording is performed.

  Prior to the original information recording / reproducing operation, the system control unit 8 performs the recording / reproducing operation under the optimum conditions corresponding to the recording / reproducing speed during the original information recording / reproducing operation on the optical disc 1. Then, an OPC (Optical Power Control) operation is executed in advance to obtain the recording / reproducing speed-optimal power characteristic. Therefore, the system control unit 8 refers to the recording / reproduction speed-optimum power characteristic acquired in advance by the OPC operation by the parameter indicating the quality of the reproduction RF signal supplied at the time of the recording / reproduction operation. The optical power capable of recording / reproducing under conditions is acquired, and the laser driver 13 is controlled via the optical power control unit 14. As a result, the laser light with the optical power optimized from the optical pickup 5 is irradiated by the drive signal from the laser driver 13, and information can be recorded and reproduced on the optical disc 1 appropriately.

  Next, the recording / reproducing operation of the optical disc recording / reproducing apparatus 100 when there are physical abnormal states such as scratches, fingerprints, warpage, surface shake, and pigment unevenness on the optical disc 1 will be described. The recording / reproducing operation in the case where a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1 is completely different from the case of the existing optical disc recording / reproducing apparatus 200 described above. It forms one of the characteristics. FIG. 2 is an operation flowchart for explaining an example of the recording / reproducing operation in the optical disc recording / reproducing apparatus according to the present invention. When the optical disc recording / reproducing apparatus 100 shown in FIG. The recording / reproducing operation is described.

  If a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, the peak level, bottom level, and amplitude level of the reproduced RF signal at that location greatly change beyond predetermined values. become. In the operation flowchart of FIG. 2, the system control unit 8 does not detect a large change in the peak level, bottom level, or amplitude level of the reproduction RF signal supplied from the peak / bottom detection circuit 10 (NO in step S1). ), Assuming that no physical abnormal condition exists on the optical disc 1, the recording / reproducing operation using the optimum optical power acquired in advance by the OPC operation is continued.

  On the other hand, when a large change is detected (YES in step S1), it is detected that a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1. In addition to the information on the peak level, bottom level, and amplitude level of the reproduction RF signal as described above, for example, the reflectance of the optical disc 1, the asymmetry β, the amount of change of the focus error signal, the tracking error signal, and the like are used. Alternatively, when it is detected that there is a large variation in these pieces of information, it may be determined that there are scratches, fingerprints, or the like on the optical disc 1.

  In such a case, a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, and in this case, the system control unit 8 uses this to compensate for changes in the peak level and bottom level of the reproduction RF signal. By generating a power control signal for the optical power control unit 14 so as to increase the optical power emitted from the optical pickup (OPU) 5 in accordance with the magnitude of the level change, the optical pickup (OPU) from the laser driver 13 is generated. ) The signal level of the drive signal to 5 is increased, and the laser beam that has been powered up is emitted from the optical pickup (OPU) 5 onto the optical disc 1 (step S2).

  Further, when a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, the focus servo state or the tracking servo state may be greatly deviated. In order to prevent this, the system control unit 8 temporarily outputs a focus servo and tracking servo hold signal for maintaining the current focus servo state and tracking servo state to the servo circuit 4 as a servo control signal (step S3). As a result, the servo circuit 4 performs control so that the focus servo state and tracking servo state so far are maintained. The operation so far is the same as that of the existing optical disc recording / reproducing apparatus 200 described above, but the subsequent operation is completely different.

  That is, when a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1, a servo hold signal is output and the focus servo state or tracking servo state is set to be held. Then, it is checked whether or not a predetermined time, that is, the switching determination time Tw has elapsed (step S4). If the predetermined time Tw has not yet elapsed (NO in step S4), the focus servo and tracking servo hold signals are continuously output to the servo circuit 4 as servo control signals (step S7). .

On the other hand, if the fixed time Tw has elapsed since the start of the output of the servo hold signal (YES in step S4), the amplitude level of the reproduction RF signal becomes equal to or higher than a predetermined threshold value _VTH. It is confirmed whether or not (step S5). As a method for checking the signal level of the reproduction RF signal, instead of using the amplitude level, whether or not the peak level of the reproduction RF signal is _{equal to} or higher than a predetermined threshold V _THp or the bottom level is predetermined. It is also possible to check whether or not the level has fallen to a level equal to or lower than the threshold value V _THb .

When the amplitude level of the reproduction RF signal is equal to or higher than the predetermined threshold V _TH (YES in step S5), it is assumed that the focused state on the optical disc 1 is still maintained, and the process proceeds to step S7. Thus, the focus servo and tracking servo hold signals continue to be output to the servo circuit 4 as servo control signals. On the other hand, when the amplitude level of the reproduction RF signal is smaller than the predetermined threshold value V _TH (NO in step S5), it is regarded as being out of focus on the optical disc 1, and the focus servo and In order to restart the servo control of the tracking servo, a servo control signal for switching the focus servo and tracking servo to the on state is generated and supplied to the servo circuit 4 (step S6). As a result, the servo circuit 4 can resume servo control based on the focus error and tracking error, and can correctly focus on the track position of the optical disc 1, and maintains the signal level of the reproduction RF signal at an appropriate signal level. can do.

In the operation flowchart shown in FIG. 2, it is a case where a fixed time Tw has elapsed since the start of the output of the servo hold signal (YES in step S4), and the amplitude level of the reproduction RF signal is set in advance. When the threshold value _VTH is smaller than the predetermined threshold value _VTH (NO in step S5), the servo-on signal for returning the focus servo and tracking servo to the on state is generated for the first time. It is not limited to only.

For example, in some cases, when a certain time Tw has elapsed since the start of the output of the servo hold signal (YES in step S4), a servo-on signal is once generated to hold the focus servo and tracking servo. You may make it return to an ON state from a state. In this case, after the return to the ON state, if the amplitude level of the reproduction RF signal is not equal to or higher than the predetermined threshold value V _TH (YES in step S1), a physical abnormal state such as a scratch or a fingerprint is present. Assuming that it continues, the recording / reproducing operation after step S2 in FIG. 2 is resumed.

Alternatively, the amplitude level of the reproduction RF signal is not equal to or higher than the predetermined threshold value V _TH regardless of the elapsed time from the start of the output of the servo hold signal (that is, skipping step S4) ( If YES in step S5), it may be assumed that the focus state is greatly deviated, and the servo hold state may be immediately returned to the on state. Further, in such a case, in step S3, the servo hold state may be controlled as it is without setting the servo hold state once.

  The recording / reproducing operation control method shown in FIG. 2 in the case where a physical abnormal state such as a scratch or a fingerprint exists on the optical disc 1 as described above will be further described with reference to a control signal time chart. FIG. 3 is a time chart showing an example of a signal waveform of a control signal in the optical disc recording / reproducing apparatus 100 according to the present invention. Each signal waveform is schematically shown to the extent that the operation shown in FIG. 2 can be understood, and the present invention is not limited to such a signal waveform. For example, the polarity of the control signal may be different from that illustrated, or a differential signal may be used. For comparison, FIG. 6 shows a time chart of signal waveforms of control signals in the conventional optical disc recording / reproducing apparatus 200 described above as the background art. Here, FIG. 6 shows a recording / reproduction control operation in the case where the same reproduction RF signal as in FIG. 3 is output from the RF amplifier 6.

  3 and 6, (A) is a signal waveform of a reproduced RF signal reproduced by the RF amplifier 6, and (B) is a system control unit 8 according to the detection result from the peak / bottom detection circuit 10. , 8A are signal waveforms of power control signals generated and output to the optical power control unit 14, respectively. (C) is the system control unit 8 according to the detection result from the peak / bottom detection circuit 10. , 8A are signal waveforms of servo hold signals that are respectively generated and output to the servo circuit 4, and (D) is a servo in the system control unit 8 according to the detection result from the peak / bottom detection circuit 10. This is a signal unique to the present invention that does not exist in the conventional optical disc recording / reproducing apparatus 200 and is output to the servo circuit 4 for switching from the hold signal. A signal waveform of that servo-on signal.

  3 and 6, (E) is the signal waveform of the servo signal output from the servo circuit 4 in response to the servo hold signal and servo-on signal shown in (C) and (D), and (F) is ( B) is a signal waveform of the intermediate reproduction RF signal after the level reduction is compensated for by the power control signal shown in B), and (G) is further obtained by maintaining the in-focus state by the servo signal shown in (E). This is the signal waveform of the final reproduction RF signal, that is, the compensation RF signal, which has been compensated for level reduction. Here, in the case of the conventional optical disc recording / reproducing apparatus 200 of FIG. 6, the servo hold state continues in the existence range of physical abnormal states such as scratches and fingerprints, so that the intermediate reproduction RF signal of FIG. The signal waveform is exactly the same as that of the final reproduction RF signal in FIG.

  As shown in FIGS. 3 (A) and 6 (A), it is assumed that there is a scratch on the track of the optical disc 1 over the section indicated by T1, and a fingerprint exists over the section indicated by T2. At each location, the amplitude of the reproduction RF signal becomes small, and the bottom level of the reproduction RF signal is lower than a predetermined abnormal state detection threshold Vc for detecting a physical abnormal state such as a scratch or a fingerprint. The situation is not lowered to the level. Thereby, it is detected that a physical abnormal state such as a scratch or a fingerprint exists at each location. Also, generally, the fingerprint attachment range extends to a wider range than the scratched location, and T1 <T2.

  As shown in FIG. 3, in the optical disc recording / reproducing apparatus 100 according to the present invention, when a predetermined time Tw has elapsed since the start of the output of the servo hold signal, the servo on state is changed from the servo hold state. In order to make it possible to return to the predetermined time Tw, the elapsed time from the start of the servo hold signal output to a predetermined time Tw is counted. In the example of FIG. 3, the scratch temporal generation range T1 is shorter than the fixed time Tw, and the return operation to the servo-on state is not performed within the scratch generation range, while the fingerprint temporal adhesion range T2 is not performed. Indicates a case where the servo-on signal is generated and the return operation to the servo-on state is performed even in the fingerprint attachment range (ie, T1 <Tw <T2).

Further, in the example shown in FIG. 3, a predetermined time Tw elapses, the signal level of the reproduction RF signal is lowered, and the bottom level of the reproduction RF signal is a predetermined lower limit threshold value for indicating the in-focus state. An example is shown in which the servo-on state is restored when the level is not lowered to a level lower than _VTHb . Furthermore, in this case, the case where the time point when the predetermined time Tw elapses coincides with the time point when the bottom level no longer _falls below the lower limit threshold value V _THb indicating the in-focus state, The period in which the servo is held is Tw, and the period in which the servo is turned on is T _ON even within the fingerprint attachment range (ie, T2 = Tw + T _ON ).

  Next, the time chart of FIG. 3 will be further described with reference to the time chart of FIG. 6 for reference.

  As shown in FIG. 3A, the reproduced RF signal reproduced has a signal level lowering due to a physical abnormal state such as a scratch or a fingerprint, and the bottom level is lower than the abnormal state detection threshold Vc. When the system control unit 8 detects that the level has not been lowered to a low level, as shown in FIG. 3B, due to a physical abnormal state such as a scratch or a fingerprint over the respective detection periods (T1, T2). In order to compensate for the decrease level of the optical power, a power control signal for increasing the optical power level is generated and output to the optical power control unit 14. This operation is exactly the same in the conventional optical disc recording / reproducing apparatus 200 shown in FIG.

  As a result, as shown in FIG. 3 (F) and FIG. 6 (F), in the presence of physical abnormal conditions such as scratches and fingerprints, the laser power emitted from the optical pickup 5 is increased, and the RF amplifier By improving the signal level of the reproduction RF signal from No. 6, the decrease in the level of the reproduction RF signal is compensated, the amplitude level is expanded to an appropriate level, the reproduction quality of the reproduction RF signal is improved, and signal recording is performed. The reproduction operation can be performed more appropriately.

  Further, as shown in FIG. 3C, when the system control unit 8 starts generating a power control signal (CONTROL signal) for increasing the optical power (that is, a physical abnormal state such as a scratch or a fingerprint). At the same time, the servo hold signal for setting the focus servo and the tracking servo to the hold state is generated and output to the servo circuit 4 in order to keep the servo state as it is at the time The time counting for counting the elapsed time of the servo hold state from this time is started. On the other hand, as shown in FIG. 6C, in the conventional optical disc recording / reproducing apparatus 200, the operation of generating the servo hold signal and outputting it to the servo circuit 4 is exactly the same. An operation for counting the elapsed time is not performed.

Further, as shown in the fingerprint attachment range of FIG. 3A, even if the state set in the servo hold state passes a predetermined time Tw, a physical abnormal state such as a scratch or a fingerprint is still present. As shown in FIG. 3 (F), even if the intermediate reproduction RF signal is powered up by the power control signal, the signal level of the reproduction RF signal is low and the bottom level of the reproduction RF signal is in focus. If the level is not lower than the lower limit threshold value V _THb indicating that the focus state is far from the focused state, a servo-on signal for switching the servo state to the on state is assumed as shown in FIG. At the same time, the servo hold state is returned to the original state as shown in FIG.

  As a result, as shown in FIG. 3E, the servo circuit 4 returns to the servo-on state even in the presence of a physical abnormal state such as a scratch or a fingerprint. As shown in FIG. 3 (G), the signal level of the final reproduction RF signal, that is, the compensation RF signal (in the example of FIG. 3 (G)) is operated as the servo is turned on. , The bottom level) will be improved. On the other hand, as shown in FIG. 6E, in the conventional optical disc recording / reproducing apparatus 200, the servo hold state continues as long as the physical abnormal state such as a scratch or a fingerprint exists. Thus, the signal level of the final reproduction RF signal in FIG. 6 (G) is exactly the same as in FIG. 6 (F), and is not improved at all, and the state greatly deviating from the focused state continues forever. There is a risk that.

In FIG. 3, as described above, the time point when the predetermined time Tw has elapsed in the fingerprint attachment range and the bottom level of the reproduction RF signal are not lowered to a level lower than the lower limit threshold V _THb indicating the in-focus state. However, the elapsed time may be different from the detected time. In such a case, if the conditions of both are not met, the servo The hold state is continued, and when it is aligned, the servo-on state is restored. However, as described above, the present invention is not limited to such an operation, and may return to the servo-on state immediately after a predetermined time Tw has elapsed in the fingerprint attachment range. It may be possible to immediately return to the servo-on state when it is detected that the level has not been lowered to a level lower than the lower limit threshold V _THb indicating the in-focus state.

Alternatively, instead of detecting that the bottom level of the reproduction RF signal is not lowered to a level lower than the lower limit threshold value V _THb indicating the in-focus state, the upper limit threshold value V indicating that the peak level of the reproduction RF signal indicates the in-focus state. _It may be detected that the level has become lower than _THp , or it may be detected that the amplitude level of the reproduction RF signal has become smaller than the threshold value V _TH indicating the in-focus state. Furthermore, instead of using the peak level, the bottom level, and the amplitude level of the reproduction RF signal, the determination may be made using reflectance, modulation degree, asymmetry β, jitter, deviation, and the like.

As described above in detail, according to the present invention, when the level of the reproduction RF signal is lowered at a location where an abnormal state such as a scratch on the optical disk or a fingerprint is present, the emission laser power of the optical pickup is increased, and By switching the focus servo and tracking servo to the hold state, the level reduction of the reproduction RF signal is improved, and further, the servo hold time becomes longer than a predetermined time, that is, the switching judgment time Tw, This is a case where a long and large physical abnormal state exists on the optical disc by returning the servo from the hold state to the on state when the amplitude level falls below a certain threshold value V _{TH in} advance. However, it is possible to maintain the in-focus state in a normal state, prevent a decrease in the level of the reproduction RF signal, and improve the quality of the reproduction RF signal. Quality deterioration can be prevented.

That is, a physical abnormal state such as a scratch or a fingerprint on an optical disk is detected, and the laser beam power from the optical pickup is increased while the optical pickup (OPU) is recording / reproducing the location of the abnormal state. At the same time, the focus servo and tracking servo are once switched to the hold state. As shown in FIGS. 3C and 3D, the servo hold time exceeds a predetermined time, that is, a switching determination time Tw, and / or a certain threshold the signal level of the reproduced RF signal has predetermined to indicate an in-focus state (e.g., amplitude level preset threshold value V _TH) at the time of or lower than, the hold state servo By switching from the ON state to the ON state, a stable reproduction RF signal can be obtained.

Here, the fixed time for switching from the servo hold state to the on state, that is, the switching determination time Tw is generally the optical disk surface shake amount ΔZp-p (mm) and the focus error detection of the optical pickup focus error signal (S-shaped signal). It is determined by the range ΔSp-p (μm), the disk rotational speed N (rpm), and the like. As an example, for example, when the optical disc is a CD disc and the information on this CD disc is being played back at a standard speed, the surface deflection ΔZp-p near the innermost circumference is 1 mmp-p. Then, the fixed time, that is, the switching determination time Tw is about 100 μsec. Accordingly, the condition for switching to the servo-on state is that a certain time, that is, a hold time of 100 μsec that is the switching determination time Tw has elapsed, and / or a certain threshold value at which the amplitude level of the reproduction RF signal indicates a focused state. This is the case when the voltage drops _{below VTH} .

  The configuration of the preferred embodiment of the present invention has been described above. However, it should be noted that such examples are merely illustrative of the invention and do not limit the invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made according to a specific application without departing from the gist of the present invention.

It is a block block diagram which shows an example of the block configuration of the disc reproducing apparatus by this invention. 5 is an operation flowchart for explaining an example of a recording / reproducing operation in the optical disc recording / reproducing apparatus according to the present invention. It is a time chart which shows an example of the signal waveform of the control signal in the optical disk recording / reproducing apparatus by this invention. It is a block block diagram which shows the block structure of the conventional optical disk recording / reproducing apparatus. 10 is an operation flowchart for explaining an operation for realizing an optimum recording / reproducing operation in a conventional optical disc recording / reproducing apparatus. It is a time chart of the signal waveform of the control signal in the conventional optical disk recording and reproducing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 10 Peak / bottom detection circuit 100 Optical disk recording / reproducing apparatus 11 Encoder 12 Strategy circuit 13 Laser driver 14 Optical power control part 2 Spindle motor 200 Optical disk recording / reproducing apparatus 3 Frequency generator 4 Servo circuit 5 Optical pick-up (OPU)
6 RF amplifier 7 Address detection circuit 8, 8A System controller 9 Decoder

Claims (6)

  In an optical disk recording / reproducing apparatus that records and reproduces information on an optical disk, when it is detected that there is a physical abnormal state typified by a scratch or a fingerprint on the optical disk, information is recorded at the location of the physical abnormal state. When performing a recording / reproducing operation, the laser power from the optical pickup is increased and the focus servo and tracking servo are switched to the hold state in order to compensate for a decrease in the level of the reproduction RF signal based on the physical abnormal state. When the continuation of the hold state exceeds a predetermined time during the recording / reproducing operation to the location where the physical abnormal state exists, the focus servo and tracking servo are returned from the hold state to the servo-on state. An optical disc recording / reproducing apparatus.   In an optical disk recording / reproducing apparatus that records and reproduces information on an optical disk, when it is detected that there is a physical abnormal state typified by a scratch or a fingerprint on the optical disk, information is recorded at the location of the physical abnormal state. When performing a recording / reproducing operation, the laser power from the optical pickup is increased and the focus servo and tracking servo are switched to the hold state in order to compensate for a decrease in the level of the reproduction RF signal based on the physical abnormal state. When the amplitude level or peak level or bottom level of the reproduction RF signal falls below a predetermined threshold during the recording / reproducing operation to the location where the physical abnormal state exists, the focus servo and tracking servo Disc recording / reproducing apparatus, wherein the servo is turned on from the hold state   In an optical disk recording / reproducing apparatus that records and reproduces information on an optical disk, when it is detected that there is a physical abnormal state typified by a scratch or a fingerprint on the optical disk, information is recorded at the location of the physical abnormal state. When performing a recording / reproducing operation, the laser power from the optical pickup is increased and the focus servo and tracking servo are switched to the hold state in order to compensate for a decrease in the level of the reproduction RF signal based on the physical abnormal state. During the recording / reproducing operation to the location where the physical abnormal state exists, the continuation of the hold state exceeds a predetermined time, and the amplitude level, peak level, or bottom level of the reproduction RF signal is set in advance. If the value falls below a fixed threshold value, the focus servo and tracking servo are Optical disc recording and reproducing apparatus, characterized in that to return to the state.   As means for detecting the location of the physical abnormal state on the optical disk, the amplitude level or peak level or bottom level change amount of the reproduction RF signal, the reflectance change amount, the focus error signal or the tracking error signal change amount 4. The optical disc recording / reproducing apparatus according to claim 1, wherein any one or more of them are used.   In an optical disc recording / reproducing method for recording / reproducing information on / from an optical disc, when it is detected that there is a physical abnormal state typified by a scratch or a fingerprint on the optical disc, information is recorded at the location of the physical abnormal state. When performing a recording / reproducing operation, the laser power from the optical pickup is increased and the focus servo and tracking servo are switched to the hold state in order to compensate for a decrease in the level of the reproduction RF signal based on the physical abnormal state. In a case where the continuation of the hold state exceeds a predetermined time during the recording / reproducing operation at the location where the physical abnormal state exists, and / or the amplitude level or peak level of the reproduction RF signal or When the bottom level falls below a predetermined threshold, the focus servo and tracking servo are held Optical disc recording and reproducing method for causing return to Luo servo is. As a method for detecting the location of the physical abnormal state on the optical disc, the amplitude level or peak level or bottom level change amount of the reproduction RF signal, the reflectance change amount, the focus error signal or the tracking error signal change amount 6. The optical disc recording / reproducing method according to claim 5, wherein one or more of them are used.

Images