JP4501777B2 - Optical disk device - Google Patents

Description

  The present invention relates to a technique for stably recording or reproducing information on an optical disc by irradiating a laser.

  Patent Document 1 discloses a method of holding tracking information before PID when a track trace position passes through a PID portion and releasing the holding after passing PID.

JP 07-192288 A

  In optical disk tracking servo control, a spiral track is irradiated with laser light, and the laser reflected light from the optical disk is received evenly by the light receiving elements divided in parallel with the track. Is controlled so that the laser beam is positioned at the center of the track.

  However, some optical disc tracks have a low quality master stamper in the manufacturing process of the disc, and may be distorted or bent partially or over the entire disc.

  For example, “discrete track distortion” that occurs discretely on a track. In addition, "continuous track distortion" that generates fine distortion throughout the track. In addition, in an optical disc having a sector structure, such as a DVD-RAM, “PID leakage distortion” that occurs in the vicinity preliminarily defined by a physical address (PID) also occurs due to the low quality of the stamper as described above.

Optical disks manufactured with the same stamper all have the same track distortion at the same location, and have a significant adverse effect as a disturbance in tracking control.
Discrete track distortion is not regular but has circularity (track distortion occurs every rotation in a predetermined long radius direction). Also, continuous track distortion occurs over the entire track. The PID leakage distortion is characterized by regular distortion with respect to the physical address of the optical disk. These track distortions may cause the track pitch to become coarse and dense, and may cause the adjacent tracks of the recorded track to be cross-erased during track recording. There is a case.

  In addition, in the case of discrete track distortion, the tracking servo is disengaged, causing a problem that reproduction and recording are impossible. Further, since the PID portion in the DVD-RAM is configured at a position straddling the recording track, it is not track distortion, but has the property that the tracking control information changes due to the laser reflected light shifting. For this reason, there is a problem that the track servo is disengaged as in the case of track distortion.

  In the method disclosed in Japanese Patent Application Laid-Open No. 07-192288, in which the track information is temporarily held for the track distortion portion or the PID leakage distortion portion which is a cause of deteriorating the tracking state, the track at the holding start point is not distorted. It is particularly effective. However, for example, when the tracking information of the PID leakage distortion portion is held for an optical disc having continuous track distortion, when the track information before PID leakage distortion is information away from the track median value, the holding release is performed. A track deviation occurs at a point, or the track comes off.

  It is unclear whether the optical disk is in a discrete track distortion, a continuous track distortion, or a PID leakage distortion. For example, for an optical disk in which there is no PID leakage distortion and a continuous track distortion occurs, Holding the tracking information of the PID leakage distortion portion unconditionally reduces the tracking performance. In view of the above problems, an object of the present invention is to provide a tracking servo suitable for track distortion in accordance with the track distortion detection result by detecting a track distortion state at the time of loading a disk.

  To realize the present invention, a servo device of an optical disc apparatus for recording or reproducing data on an optical disc, which has a plurality of tracks extending in a spiral shape and each track is composed of a plurality of sectors Timing signal generating means for generating a timing signal related to the connected portion of the sector, and a gate for generating a gate signal for a predetermined time based on the timing signal in a servo device of an optical disk apparatus for recording or reproducing data on an optical disk A signal generation unit; a track servo unit that performs tracking control using a tracking error signal corresponding to a deviation amount of the light beam spot from the track center position of the optical disc; and a tracking error signal shift amount in the gate signal period is detected. Track distortion detection means is provided for responding to the track distortion detection result. Te, and configured to detect the presence or absence of the optical disk-specific track distortion.

  In addition, a tracking error signal corresponding to the amount of deviation of the light beam spot from the track center position of the optical disk is sent to an optical disk device servo device for recording / reproducing data on an optical disk having continuous tracks extending in a spiral shape. And a track distortion amount detecting means for detecting a tracking error signal shift amount of the optical disk, and detecting the presence or absence of a track distortion peculiar to the optical disk according to the track distortion detection result.

  Further, in the above two configurations, a second gate signal that generates a second gate signal that is equal to or less than a gate section of the gate signal in accordance with the detection result of the presence or absence of the track distortion inherent to the optical disc is related to the gate signal. The generating means and the holding means for pre-holding the tracking error signal in the second gate section are provided.

Further, the track servo means includes a band-specific amplitude limiting means capable of arbitrarily limiting the control width of the track control for each of a plurality of frequency bands, and a predetermined frequency band among the band-specific amplitude limiting means In this configuration, means for limiting the amplitude in track control is provided.
The band-specific amplitude limiting means is divided into a high-frequency band and a low-frequency band, and a band-specific amplitude limiting means is provided that limits the amplitude of track control in the high-frequency band.

The track servo means includes a band-specific gain adjusting means that can arbitrarily adjust the gain value of the track control for each of a plurality of frequency bands, and the track control gain in a predetermined frequency band among the band-specific gain adjusting means. It was set as the structure provided with the means to lower.
The band-specific gain adjusting means is divided into a high-frequency band and a low-frequency band, and is configured to include a band-specific gain adjusting means for reducing the gain value for track control in the high-frequency band.

  According to the present invention, it is possible to perform good tracking control in accordance with the track state of the disk.

  Embodiments according to the optical disc apparatus of the present invention will be described below. FIG. 1 is a schematic block diagram showing the configuration of an optical disc apparatus according to an embodiment of the present invention. FIG. 1 shows an optical disk capable of recording data with a laser beam (here, DVD-RAM will be described here, but is not limited to DVD-RAM). The groove is a track for recording data. The track has a meandering shape of a certain length called a wobble, and the wobble is used as an encoder signal for controlling the rotation of the optical disc. The optical disk 1 is mounted on a spindle motor 2 and driven to rotate.

  At the time of recording, the optical pick 3 reads the wobble of the optical disc, the reproduction RF unit 8 performs amplification operation, demodulation operation, and waveform shaping, and a wobble signal (Wob) indicating the linear velocity is input to the spindle servo unit 5. The spindle servo section 5 performs constant track linear velocity control (CLV) so that the period of the Wob signal is constant.

  At the time of reproduction, rotation control is performed at a constant angular velocity (CAV) rotation speed based on CLV control or an FG signal (rotation information from the encoder of the spindle motor 4) that is rotation cycle information of the spindle motor 4.

  The optical pick 3 is equipped with a light emitting source (not shown) such as a laser diode, for example, and the light condensed by the objective lens is irradiated onto the optical disc 1. For example, a laser diode is preferably used as the light source. The light emitted from the light source is transmitted or reflected by various optical components, and finally the light spot collected by the objective lens 3 is irradiated onto the optical disc 1. Further, the light reflected by the optical disk 1 is converted into an electric signal by a photo detector or the like and input to the reproduction RF unit 8.

  The optical pick 3 is mounted on the slide mechanism unit 4 and is movable in the radial direction of the inner circumference and the outer circumference of the optical disc 1 and performs an approximate positioning movement to the target track.

  The optical pick 3 is supported by an actuator that can be shifted in the track direction and the focus direction, and the focus servo unit 6 that is movable control to a focus position at which the optical spot 1 is irradiated with an optimal light spot, on the track The track of the optical disk is traced by the track servo section 7 which is movable control to the track position that accurately follows the above.

  The TE signal output from the optical pick 3 outputs the characteristics of the graph shown in FIG. 8, and at the center point of the track width of 0.615 um, a zero value is output as the tracking Err (TE) signal level, and the amount of change in the X-axis direction In response to this, the TE potential outputs a positive value and a negative value. The track servo unit 7 allows the optical pick 3 to trace the center of the track by performing negative feedback control on the radial position of the optical pick based on the TE signal. The focus operation is the same as that of the track servo unit, and the distance between the optical pick 3 and the optical disk can be set to a constant value by negative feedback control of the FE signal.

  The track is formed in a spiral shape. For example, in a DVD-RAM or the like, address (hereinafter referred to as PID) information is embedded in the spiral track every predetermined section. This PID discretizes the continuous physical shape of the track, and in some cases, track distortion (PID leakage distortion) is formed in the vicinity of the PID. This occurs due to the accuracy of the disk stamper in the disk process, and does not necessarily cause PID leakage distortion.

  However, along with the price reduction of disk media, a large number of disks with disk distortion and PID leakage distortion are on the market due to a decrease in quality management in the disk manufacturing configuration. The track servo section 7 performs negative feedback control of the PID leakage distortion portion to the optical pick 3, and there is a problem that the track deviation increases in this portion. This degrades the tracking performance of the optical disc.

  In the DVD-RAM, the number of sectors for each area (ZONE) provided in the radial direction increases as shown in FIG. Therefore, at the ZONE boundary, as shown in FIG. 2, the appearance timing (L1) of the adjacent PID differs for each individual PID. The time of L1 with respect to the sequential appearance numbers of PID is known from the structure of the DVD-RAM and the angular velocity of the disc, and the PID leakage position can be estimated in advance.

A description will be given of a method for estimating the PID leakage position.
The DVD-RAM is characterized in that recording is alternately performed on the land portion and the groove portion for each round of the disk. At the switching point between the land portion and the groove portion, the PIDs of all ZONEs are aligned on the same straight line in the radial direction. In the structure. Based on this land groove switching point, the number of PIDs per disk of the current ZONE is known as shown in FIG. 3, and the linear velocity of the disk is also an FG signal or WOB indicating the angular velocity of the spindle shown in FIG. Can be detected by signal.

  Assuming that the time per one rotation of the disk is T1 (sec), for example, at the boundary portion from ZONE0 to ZONE1, the time of T2 = (T1 × (1/26) − (1/25)) / 25 from FIG. The calculation results in a change in the value of L1 in FIG. Therefore, it is easy to predict the appearance timing of PID leakage distortion in advance.

  FIG. 2 is a diagram showing the PID portion of the ZONE boundary portion of the DVD-RAM. A state in which track distortions 21 and 22 are generated in adjacent ZONEs in the radial direction of PIDs 20 and 23 is shown. This is the PID leakage distortion. For example, a case where the optical pick 3 traces Track n + 08 indicated by an arrow 24 will be described. In the PID portion in the middle of the track, the TE signal becomes violent as shown by the TE signal in FIG. This occurs because the data reflection mode differs depending on the PID. Furthermore, the TE signal becomes unnatural as if it passed the pseudo PID due to the track bending due to the PID leakage after passing the PID. When the TE signal is violated, the track trace is shifted from the center. First, the TE signal of the PID part is shaken by holding the TE signal before the PID when passing through the PID part and releasing the hold after passing through the PID part to reduce the fluctuation of the PID part.

On the other hand, even in the TE rampage due to PID leakage, as shown in FIG. 4, the TE signal rampage against the PID leak is reduced by the hold signal in the same manner as described above for the PID leak 25 after L1 time from the PID portion. With the two hold signals as described above, as shown in the TEHOLD waveform shown in FIG. 4, it is possible to reduce the fluctuation of TE with respect to the PID portion and PID leakage.
However, as a problem in the case of HOLDing the TE signal, in the case of a disk having a track distortion with respect to the entire track area, the TE may be violated after the HOLD is released. FIG. 6 shows an example of a disc having track distortion over the entire track.

  Such a disk includes noise over the entire TE signal as shown in FIG. 5A, and the TE signal at the HOLD start point of the TE signal may not hold the signal indicating the original track position signal. As a result, the track swing increases at the hold release point of the PID portion and the hold release point of the PID leakage portion.

  In addition, there is a disk having a track distortion over the entire track shown in FIG. 5B and no PID leakage. In such a disk, outputting a PID leakage hold signal at a position where PID leakage is assumed, regardless of whether or not PID leakage occurs, lowers the tracking performance in the PID leakage hold release unit. In the present invention, the presence / absence of PID leakage is determined, and whether or not to hold the TE signal of the PID leakage portion can be controlled according to the determination result. The reproduction signal output from the optical pickup in FIG. 1 is input to the reproduction RF unit 8 and subjected to waveform amplification processing and waveform equivalent processing. This signal is input to the data demodulator 9, and information contained in the data is demodulated. In this data, PID (address signal and signal detection trigger) is extracted by the PID detection unit 10, the ZONE number is extracted by the ZONE detection unit 11, the track number is extracted by the TrackNo detection unit 12, and each PID is extracted. This is input to the leakage prediction gate generation unit 13.

  The PID leakage prediction gate generation unit 13 measures the PID signal appearance period based on the data reproduction clock signal, and uses the current ZONE number and the current track number to generate a gate signal for a period in which PID leakage occurs (for example, only that interval). Is a HI level signal). The PID leakage gate signal is input to the switch 14 and operates as a switch switching signal. The switch 14 is a switch circuit that switches between the TE signal and the Vref signal. The switch 14 is switched to a TE signal only for a period that is predicted to leak PID and is input to the comparator 15.

  The comparator 15 is a comparator that compares the TE signal during the PID leakage period with a magnitude greater or smaller than the comparison potential Vref2. The output signal of the comparator 15 is input to the PID leakage determination unit 15 to determine whether or not the TE signal is violated due to the PID leakage, and the determination result of the presence or absence of PID leakage of the currently mounted disk is obtained. Output from terminal 19. The PID leakage is unique for each disk, and the PID leakage present mode can be switched to the PID leakage absent mode by performing the PID leakage determination operation after mounting the disk.

  As described above, according to the present embodiment, it is possible to determine the presence or absence of PID leakage in the loaded disk. By using this discrimination result, there is an effect that the control can be switched for each disk.

Next, a distortion detection method for the entire track will be described with reference to FIG.
A disk having a track distortion over the entire track, for example, a track distortion as shown in FIG. In tracking control of media having such track distortion, there is a case where track swing is less when the hold operation is not performed on the TE signal as much as possible. The reason is that, as described above, when the TE level value at the hold start point of the TE signal is different from the average track deviation information, track swing occurs at the hold release point.

  Therefore, in this embodiment, the disc currently mounted is provided with means for determining whether or not the track bend is large, and it is configured to switch whether or not to perform the PID leakage HOLD operation based on the determination result. . FIG. 9 shows a configuration diagram for detecting track bending. Here, it is necessary to distinguish TE signal fluctuations due to discrete minute defects or dirt and TE fluctuations due to track bending. In the configuration of FIG. 9, the comparator 15 detects a track shift amount equal to or greater than a predetermined value in the TE signal. The output of the comparator 15 is not distinguished from any minute defect or track bending, and if the track shift is equal to or greater than a predetermined value (Vth2), it is determined that there is a track bending.

  These signals are temporarily stored in the memory unit 90 once. The detection result is stored in the memory unit 90 and input to the track bending detection unit. On the other hand, in order to correlate the occurrence timing of the track bending with the disc rotation angle, it is detected whether or not the same rotation angle (rotation timing) TE fluctuation detection of the disc is detected based on the WOB signal. At least in the adjacent and phosphorus adjacent tracks where TE fluctuation is detected, TE fluctuation is detected at substantially the same rotation timing. On the other hand, the web counter 91 detects the rotation angle (timing) of the disk, and the number of web cycles per disk revolution in the current track is known. The count value of the web counter and the comparator 15 From this detection timing, it is possible to recognize the transition of the track with respect to the time direction.

  For example, in the case of a minute defect, a track turning signal is detected only at the timing of a specific Disk angle of Disk 1 rotation or several rotations. In the case of a disk having a track bend over the entire disk as shown in FIG. 6, a track bend signal is detected at a specific disk angle timing several times or several tens of times in the disk 1 rotation. The signal of the web counter 91 and the memory unit 90 is received by the track bending occurrence timing detection unit 92 and is output from the terminal 93 as a track bending detection signal.

  With the above-described configuration, discrete minute defect track bending is not detected. By using this track bending detection signal as the PID leakage disk mode switching signal, the HOLD operation of the PID leakage portion can be prevented when the track distortion exists over the entire disk.

  As described above, according to the present embodiment, it is possible to detect the presence or absence of track distortion over the entire track, and in accordance with the result, stop the operation of rejecting the track distortion due to PID leakage in a disk with PID leakage. Can do. When the track distortion is in the entire track area, there is an effect that it is possible to suppress the adverse effect of temporarily holding the tracking signal.

  FIG. 7 shows an overall block configuration diagram for avoiding track distortion due to PID leakage of the present invention. Description of the same constituent blocks as those in FIGS. 1 and 9 is omitted.

  First, in a medium such as a DVD-RAM in which an address such as a PID is pressed on a track, it is necessary to reject the PID portion and perform track servo control. Therefore, a gate signal (PID gate signal) for rejecting the PID portion is required. The PID gate signal is a signal that maintains a HI level, for example, with a point period after the PID detection end position as a logical signal from a point before the PID detection start.

  Therefore, it is necessary to set the logic of the PID gate signal to the HI level before a predetermined time before detecting the PID. Therefore, in this embodiment, the PID detection timing is detected by the PID detection unit 10 and the time until the next PID appears is uniquely determined from the disk rotation speed and the current track position. The PID gate signal is set to the HI level a predetermined time before the point at which the PID signal is detected (for example, 20 microseconds).

  Next, the timing for setting the PID gate signal to the LOW level is set to the LOW level after a predetermined time from the HI level setting point. The setting timing of the HI level is a method of performing predictive generation from the PID generation timing immediately before the current PID, but is not limited to this method, and any configuration can be used as long as it can generate a timing signal that can reject the PID. It may be a configuration.

  The PID gate signal passes through the 32 OR circuit and is input as a hold control signal for the TE signal HOLD unit 33. The HOLD unit 33 performs a function of pre-holding the TE signal only during a period in which the hold control signal is at the HI level, for example. Therefore, by temporarily holding the TE signal with the PID gate signal longer than the PID signal generation period, the TE signal disturbance in the PID portion can be rejected, and the track servo can be controlled stably.

  On the other hand, the OR circuit 32 logically adds the PID leakage gate signal and holds the TE signal as described above. Since the PID leakage gate signal is generated by the above-described configuration, description of the operation up to the signal generation here is omitted. The PID leakage determination unit 16 determines the track distortion state of the currently loaded disk, here, the presence or absence of track distortion due to PID leakage, and inputs it to the switching control terminal of the switch circuit 31. If the track distortion is detected at a predetermined value (Vth) or more at the timing when the PID leakage is expected (output signal from the PID leakage prediction gate generation unit 13), the disk has PID leakage distortion over the entire disk. For example, a logical value HI level is input to the switch circuit 31 as a PID leakage DISK mode switching signal, and the switch circuit 31 is switched to the A side.

  The PID leakage determination operation of the currently mounted disk is performed when the disk is mounted, and the determination result is controlled so that the switch circuit 31 is fixedly switched to either one. Further, PID leakage may be detected every time the disc is loaded, but once detected, the recognition result information may be recorded in, for example, a user area or an information area on the disc. Thereafter, the operation may be performed so as to switch the switch 31 by reading, for example, the information area of the disk, and the PID leakage determination result of the disk.

  As described above, according to the present embodiment, according to the track distortion detection result due to PID leakage, the track bending with respect to the PID leakage can be rejected, and the PID rejection operation by the disk without the PID leakage is stopped. Can do. That is, when the disc has a track distortion over the entire track and the PID is not leaked, there is an effect that the track swing due to the adverse effect of the reject operation can be eliminated.

  Next, a method of limiting the control amplitude range (hereinafter referred to as D range) for each tracking control band based on the detection result of track distortion or track distortion due to PID leakage will be described with reference to FIG. 10, the description of the same functional blocks as those in FIG. 1 is omitted. The negative feedback control of the tracking signal (TE signal) with respect to the track distortion can be dealt with by either slowing the distortion response of the track distortion or suppressing the distortion response range. In this embodiment, the tracking control band is divided into a plurality of parts. Here, for the purpose of explanation, for example, the number of divided bands is set to two, and the D range of the track distortion response band is limited to improve the tracking performance with respect to the track distortion. To do. In FIG. 10, the operation of the PID leakage determination is the same as that in FIG. Further, FIG. 10 shows a configuration in which the method of holding the TE signal with respect to the PID leakage portion on the track does not dare to cope with the stabilization of the track control with respect to the track distortion by the method of limiting the D range.

First, the division of the tracking control band, which is important in the present embodiment, will be described.
The TE signal is output from the pickup unit 3 of FIG. 10 as a voltage signal for the track deviation amount, and this signal is input to the HOLD unit 33. The HOLD unit 33 pre-holds the TE signal only in the logic signal period indicating the PID period generated by the PID gate generation unit 30 for the purpose of rejecting the TE signal disturbance of the PID unit 30. The TE signal from the HOLD unit 33 includes a compensator 1 having a band 1 characteristic (for example, a delay compensator in the present embodiment) and a band 2 characteristic (in the present embodiment, for example, for explanation). Each is input to a compensator 2 having a lead compensator. The output of the compensator is input to limit units 42 and 43 that limit the signal amplitude range of the compensator. In each of the limit units 42 and 43, a limit potential is set by a control signal from the limit control unit, and a TE signal equal to or higher than the limit value is not output. The TE signals from the respective limit units are added by the addition unit 35, and further, signals from the Seek_FF unit 34, which is a feedforward signal generation unit for performing SEEK and track jump, are added to the actuator amplifier unit 36. Input to the track servo section.

  Here, for example, if the limit control unit 44 determines that the disk has PID leakage by the PID leakage Disk mode switching signal (the output signal from the PID leakage determination unit 16), the D range on the compensator 2 side. For example, a limit limit value is input to the limit unit 43 so as to limit to 1/4. The limit limit value is input to the limit limiter 42 so that the D range of the other compensator 1 is 1/1. With the above operation, the response control range for track distortion due to PID leakage can be limited. Further, the tracking response control range is not limited in a low frequency band different from the track distortion band. It can be configured.

  In the present embodiment described above, a steady track deviation in the DC band can be ensured, and the operation dynamic range of the track swing band due to the track bending can be reduced, and the track bending can be prevented without degrading the overall tracking characteristics. There is an effect that the track swing can be reduced.

  Next, a method for limiting the control sensitivity for each tracking control band based on the detection result of track distortion due to track distortion or PID leakage will be described with reference to FIG. In FIG. 11, the description of the same function bath area as in FIG. 1 is omitted here. The negative feedback control of the tracking signal (TE signal) with respect to the track distortion can be dealt with by either slowing the distortion response of the track distortion or suppressing the distortion response range. In this embodiment, the tracking control band is divided into a plurality of parts. Here, for the sake of explanation, the divisional band is divided into two, and the tracking control sensitivity is switched for each track distortion band, thereby improving the tracking performance with respect to the track distortion. It is. In FIG. 11, the PID leakage determination operation is the same as that in FIG.

  Further, in FIG. 11, the TE signal is not held for the PID leaking portion on the track, but the track control is stabilized with respect to the track distortion by the method of limiting the tracking control impression for each band. First, the division of the tracking control band, which is important in the present embodiment, will be described. The TE signal is output as a voltage signal with respect to the track deviation amount from the pickup unit of FIG. 10, and this signal is input to the HOLD unit 33. The HOLD unit 33 pre-holds the TE signal only in the logic signal period indicating the PID period generated by the PID gate generation unit 30 for the purpose of rejecting the TE signal disturbance of the PID unit 30.

  The TE signal from the HOLD unit 33 includes a compensator 1 having a band 1 characteristic (for example, a delay compensator is used for explanation in this embodiment) and a band 2 characteristic (for example, for explanation in this embodiment). Each is input to a compensator 2 having a lead compensator. The output of the compensator is input to the Amp units 42 and 43 that adjust the signal amplitude gain of the compensator. In each of the Amp units 42 and 43, the gain value is set by the control signal from the gain control unit 52, and the TE signal is increased or decreased for each band. The TE signals from the respective Amp units are added by the adding unit 35, and further, signals from the Seek_FF unit 34, which is a feedforward signal generating unit for performing SEEk and track jump, are added to the actuator amplifier unit 36. Input to the track servo section.

  Here, for example, if the Amp unit 44 determines that the disk has PID leakage based on the PID leakage Disk mode switching signal (output signal from the PID leakage determination unit 16), the Amp unit 44 sets the gain on the compensator 2 side, for example, Set to -6dB. A gain value is input from the gain limiter 52 to the Amps 50 and 51 so that the gain of the other compensator 1 is 0 dB.

  With the above operation, the sensitivity of the response control with respect to the track distortion due to the PID leakage is lowered, and the sensitivity of the tracking response control is not lowered in a low band and a band different from the track distortion band. It can be configured.

In the present embodiment described above, a steady track deviation in the DC band can be secured and the sensitivity of the track swing band due to the track bending can be lowered, and the track swing with respect to the track bending can be reduced without degrading the overall tracking characteristics. As described above, according to the present embodiment, it is possible to determine the presence or absence of PID leakage of the loaded disk. By using this discrimination result, there is an effect that the control can be switched for each disk.

In addition, the presence or absence of track distortion over the entire track can be detected, and the operation of rejecting the track distortion due to PID leakage can be stopped in a disc with PID leakage according to the result. When the track distortion is in the entire track area, there is an effect that it is possible to suppress the adverse effect of temporarily holding the tracking signal.
Further, according to the track distortion detection result due to PID leakage, the track bending with respect to the PID leakage can be rejected, and the PID rejection operation by the disk without the PID leakage can be stopped. That is, when the disc has a track distortion over the entire track and the PID is not leaked, there is an effect that the track swing due to the adverse effect of the reject operation can be eliminated.

  In addition, a steady track deviation in the DC band can be secured, and the dynamic range of the track swing band due to track bending can be reduced, reducing track swing due to track bending without degrading the overall tracking characteristics. There is an effect that can be done.

1 is a block diagram showing a configuration of a servo control device for an optical disc apparatus according to a first embodiment of the present invention. The figure which shows the track distortion by PID leak. The figure which shows the number of sectors of each ZONE of DVD-RAM. The operation | movement waveform diagram of the 1st Example of this invention. The operation | movement waveform diagram of the 1st Example of this invention. The figure which shows the track distortion over the whole track. The block diagram which shows the structure of the servo control apparatus of the optical disk apparatus which is the 2nd Example of this invention. The figure which shows the relationship between a track | truck deviation and a track signal (TE). The block diagram which shows the structure of the servo control apparatus of the optical disk apparatus which is the 3rd Example of this invention. The block diagram which shows the structure of the servo control apparatus of the optical disk apparatus which is the 4th Example of this invention. The block diagram which shows the structure of the servo control apparatus of the optical disk apparatus which is the 5th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Spindle motor 3 Optical pick 4 Slider mechanism 5 Spindle servo part 6 Focus servo part 7 Track servo part 8 Reproduction RF part 9 Data demodulation part 10 PID detection part 11 ZONE detection part 12 TrackNo detection part 13 PID leak prediction gate generation Unit 14 switch circuit 15 comparator 16 PID leakage determination unit 20 PID unit 21 PID leakage unit 25 PID leakage unit passing TE waveform 26 PID unit passing TE waveform 30 PID gate generation unit 32 OR circuit 33 HOLD unit 34 Seek_FF unit 35 Adder 36 Amplifier unit 40 Compensator 1
41 Compensator 2
42 limit unit 44 limit control unit 45 adder 50 amplifier unit 52 gain control unit 90 memory unit 91 web counter 92 track bending occurrence timing detection unit

Claims (6)

In an optical disk apparatus having a plurality of tracks connected in a spiral shape, each track recording or reproducing data on an optical disk composed of a plurality of sectors,
Timing signal generating means for generating a timing signal related to a connected portion of the sectors;
Gate signal generating means for generating a gate signal for a predetermined time based on the timing signal;
Track servo means for performing tracking control using a tracking error signal corresponding to the amount of deviation of the optical beam spot from the track center position of the optical disc;
Track distortion detecting means for detecting a tracking error signal shift amount within the gate signal period;
Holding means for holding the tracking error signal,
When the tracking error signal displacement amount within the gate signal period is larger than a predetermined amount, the holding means causes the light spot to be on a track passing through a radial position different from the connection portion and to cause a tracking error by the connection portion. An optical disc apparatus characterized by stopping holding the tracking error signal when the signal passes through a first position which is an affected position.   The optical disc apparatus according to claim 1,
The holding means holds the tracking error signal when the light spot passes through the first position when a tracking error signal displacement amount within the gate signal period is smaller than a predetermined amount. Optical disk device.   The optical disc apparatus according to claim 1 or 2,
  The optical disc apparatus characterized in that the holding means holds the tracking error signal when the light spot passes through the connecting portion. The optical disk device according to claim 3,
  The holding means is configured to hold the light spot for a longer period than when the light spot passes through the connecting portion, and longer than the hold period when the light spot passes through the first portion. Optical disk device. 5. The optical disc apparatus according to claim 1, wherein
  The optical disc is a DVD-RAM disc compliant with the DVD-RAM standard,
  The connecting part is a PID part,
  The optical disk apparatus according to claim 1, wherein the first location is a PID leakage portion.   5. The optical disc apparatus according to claim 1, wherein the PID leakage portion is disposed at the same angular position as the PID portion.

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