JP2006059511A - Optical disk recording and playback apparatus and optical disk playback apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording and playback apparatus in which accurate clocks for rotation control and for recording can be generated by accurately detecting the quantity of wobble phase shifting between grooves even when cross talk from an adjacent groove is large when information is recorded in an optical disk in which a pre-pit or the like are not formed in a land between grooves wobbled by a fixed frequency. <P>SOLUTION: The quantity of phase shifting between wobble of a groove and wobble of an adjacent groove can be detected by detecting (109) a ratio between signal amplitude MS (108) of a wobble component included in a signal in which radial push-pull signals (101, 102) of two side beam (RB, RC) are added (104) and signal amplitude MA (107) of a wobble signal obtained from a main beam (RA). A clock for controlling disk rotation and a clock for recording are generated by using rise and/or fall of the wobble signal in accordance with the above quantity of phase shifting. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc recording / reproducing apparatus capable of recording / reproducing information on / from an optical disc having an information recording groove wobbled at a predetermined frequency, and an optical disc reproducing apparatus capable of reproducing the optical disc on which information is recorded.

Conventionally, CD-R and DVD-R are known as recordable optical disks. In these optical discs, a recording / reproducing groove is formed by wobbling from an inner circumference to an outer circumference at a constant frequency proportional to the recording frequency.
When recording / reproducing is performed on these optical discs in the recording / reproducing apparatus or the reproducing apparatus, a wobble signal is extracted from the groove and the rotation of the disc is controlled so that the wobbling frequency becomes a predetermined frequency. When recording is performed in the recording / reproducing apparatus, a recording clock is generated based on the wobbling frequency. As a result, a recording clock that is accurately synchronized with the rotation of the disk is generated.

However, in the case of an optical disc having a wobbling groove having a constant frequency in this way, the wobble phase between adjacent grooves becomes asynchronous, and there are places where the grooves approach each other. In such a location, since the crosstalk from the adjacent groove is large, the amplitude and phase of the wobble signal fluctuate, which causes a problem that accurate rotation control and recording clock generation cannot be performed.
In particular, when focusing on the phase fluctuation of the wobble signal, the wobble phase shift between adjacent grooves becomes + π / 2 as shown in FIG. 2, and the adjacent groove approaches the rising slope portion of the wobble (the portion indicated by A in FIG. 2). ), Or when the wobble phase shift between adjacent grooves becomes −π / 2 as shown in FIG. 3, and the adjacent groove approaches the falling slope portion of the wobble (the portion indicated by B in FIG. 3), the crosstalk The phase variation becomes large due to the influence of.

For example, Patent Document 1 shown below is disclosed as a method for generating an accurate recording clock even when there is an influence of crosstalk from an adjacent group.
JP-A-10-293926

  However, since the method of Patent Document 1 is intended to generate an accurate recording clock using prepits formed in the land portion between the grooves, it can be applied to a disc in which prepits are not formed. Is not possible.

  Therefore, the present invention has been made in view of the above-described problems, and when recording or reproducing an optical disc having grooves wobbled at a constant frequency, particularly an optical disc in which prepits or the like are not formed in lands between the grooves. An optical disk recording / reproducing apparatus and an optical disk reproducing apparatus capable of accurately detecting the amount of wobble phase shift between adjacent grooves and accurately controlling the rotation of the disk even when the crosstalk from the adjacent grooves is large It is an object of the present invention to provide an apparatus and an optical disk recording / reproducing apparatus capable of generating a recording clock accurately synchronized with the rotation of the disk.

This invention consists of a structure as described in the following (1)-(4) as a means to solve the said subject. That is,
(1) For an optical disc having information recording grooves and lands wobbled at a predetermined frequency, a main beam is placed on the information recording groove, and two side beams are placed on the inner and outer circumferences of the information recording groove. In an optical disc recording / reproducing apparatus for recording / reproducing information by irradiating each of the lands adjacent to the side,
Wobble signal detection means for detecting a wobble signal based on a detection signal reflected from the information recording groove and obtained from the main beam;
After correcting and adding the time lag of the first and second radial push-pull signals obtained from the side beams reflected by the lands adjacent to the inner and outer peripheral sides of the information recording groove, A signal corresponding to the wobble component of the information recording groove is extracted, the extracted signal is amplified, the amplitude of the wobble signal is detected, and the amplitude of the extracted and amplified signal and the amplitude Detecting a ratio between the amplitude of the wobble signal and detecting a phase shift between the wobble signal and the wobble signal of the adjacent groove;
A clock generating means for generating a recording clock and an optical disc rotation control clock using either one or both of rising and falling edges of the wobble signal;
Clock generation control means for controlling the clock generation means according to the phase deviation information detected by the phase deviation detection means;
An optical disc recording / reproducing apparatus comprising:
(2) The phase shift detection means detects the phase shift as + π / 2 when the wobble of the adjacent group is closest to the wobble rising slope portion of the information recording groove, and the wobble falling of the information recording groove The phase shift is set to be detected as -π / 2 when the wobble of the adjacent group is closest to the slope portion,
The clock generation control means generates the optical disk rotation control clock using the falling edge of the wobble signal in the range where the phase shift includes at least + π / 2 ± π / 8, or the recording clock And the optical disk rotation control clock is generated so that the optical disk rotation is performed using the rising edge of the wobble signal in a range where the phase shift includes at least −π / 2 ± π / 8. Generating a control clock, or controlling the clock generation means to generate the recording clock and the optical disc rotation control clock;
The optical disk recording / reproducing apparatus according to claim 1.
(3) For an optical disc having an information recording groove and land wobbled at a predetermined frequency, a main beam is placed on the information recording groove, and two side beams are placed on the inner and outer circumferences of the information recording groove. In an optical disk reproducing apparatus for reproducing information by irradiating each of the lands adjacent to the side,
After correcting and adding the time lag of the first and second radial push-pull signals obtained from the side beams reflected by the lands adjacent to the inner and outer peripheral sides of the information recording groove, A signal corresponding to the wobble component of the information recording groove is extracted, the extracted signal is amplified, the amplitude of the wobble signal is detected, and the amplitude of the extracted and amplified signal and the amplitude Detecting a ratio between the amplitude of the wobble signal and detecting a phase shift between the wobble signal and the wobble signal of the adjacent groove;
A clock generating means for generating a recording clock and an optical disc rotation control clock using either one or both of rising and falling edges of the wobble signal;
A clock generating means for generating an optical disk rotation control clock using either one or both of rising and falling edges of the wobble signal;
Clock generation control means for controlling the clock generation means according to the phase deviation information detected by the phase deviation detection means;
An optical disc reproducing apparatus comprising:
(4) The phase shift detection means detects the phase shift as + π / 2 when the wobble of the adjacent group is closest to the wobble rising slope portion of the information recording groove, and the wobble falling of the information recording groove The phase shift is set to be detected as -π / 2 when the wobble of the adjacent group is closest to the slope portion,
The clock generation control means generates the optical disk rotation control clock using the falling edge of the wobble signal in the range where the phase shift includes at least + π / 2 ± π / 8, or the recording clock And the optical disk rotation control clock is generated so that the optical disk rotation is performed using the rising edge of the wobble signal in a range where the phase shift includes at least −π / 2 ± π / 8. Generating a control clock, or controlling the clock generation means to generate the recording clock and the optical disc rotation control clock;
4. An optical disk reproducing apparatus according to claim 3, wherein

  In the present invention, when recording / reproducing an optical disk having an information recording groove wobbled at a constant frequency, the radial push-pull signals of the lands adjacent to the inner and outer circumferences of the grooves obtained by the two side beams are added. By detecting the ratio of the signal amplitude of the wobble component contained in the signal and the signal amplitude of the wobble signal obtained from the main beam, the amount of phase shift between the wobble of the groove and the wobble of the adjacent groove is detected, and this phase shift By generating the disk rotation control clock and recording clock using only the rise of the wobble signal, only the fall, or both the rise and rise according to the amount, crosstalk from adjacent grooves can be prevented. Even if it is large, it is possible to accurately control the rotation of the disc. Years, since it is possible to generate an accurate recording clock synchronized with the rotation of the disk, which makes it possible to less favorable recording and reproducing errors.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an optical disc recording / reproducing apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram of an optical disk recording / reproducing apparatus according to a first embodiment of the present invention, FIG. 4 is a diagram showing irradiation positions of the main beam and two side beams on the optical disk in the present invention, and FIG. FIG. 6 is a diagram showing a configuration example of a phase shift detection circuit according to the present invention, FIG. 7 is a diagram showing detection signals when the wobble phase of the groove and the adjacent groove is the same phase, and FIG. FIG. 9 is a diagram showing detection signals when the wobble phase of the groove adjacent to the groove is shifted by + π / 2, and FIG. 9 is a diagram showing detection signals when the wobble phase of the groove adjacent to the groove is shifted by −π / 2. FIG. 10 is a diagram showing each detection signal when the wobble phase of the groove adjacent to the groove is opposite, and FIG. 11 is a configuration of the wobble signal phase comparison circuit in the present invention. FIG. 12 is a diagram illustrating an example, FIG. 12 is a diagram illustrating a binarized wobble signal when the wobble phase shift between adjacent grooves is + π / 2, and FIG. 13 is a wobble phase shift between adjacent grooves is −π / 2. FIG. 14 is a diagram showing the relationship between the amplitude ratio between the wobble signal and the wobble component extraction signal and the amount of phase shift.

First, the optical pickup portion in the optical disk recording / reproducing apparatus of the present embodiment will be described with reference to FIG.
In FIG. 5, the laser 1 of the optical pickup PU10 emits a recording beam or a reproduction beam in accordance with a driving signal from a laser driving circuit (16 in FIG. 1) to be described later. The emitted laser beam is converted into parallel light by the collimator lens 2 and is split into a main beam and two side beams by the diffraction element 3. The split beam passes through the beam splitter 4 and then is irradiated onto the optical disc 6 by the objective lens 5 so that the spot of the main beam RA is on the groove G and the spots of the two side beams RB and RC as shown in FIG. Are formed on adjacent lands LB and LC, respectively.

  The reflected light corresponding to the main beam RA and the two side beams RB and RC reflected from the optical disc 6 passes through the objective lens 5 and is then reflected by the beam splitter 4 toward the detection lens 7. In the detection lens 7, the reflected lights corresponding to the beams RA to RC are condensed on the photodetectors 8A to 8C, respectively. In the photodetector 8A, the reflected light corresponding to the main beam RA is detected by the light receiving unit divided into four corresponding to the radial direction (radial direction) and the circumferential direction (tangential direction), and the detection signal SA1 of the groove G is detected. ~ SA4 is output. In the photodetectors 8B and 8C, the reflected light corresponding to the side beams RB and RC is detected by the light receiving unit divided into two corresponding to the radial direction on the optical disc 6, and the detection signals SB1 and SB2 of the lands LB and LC are detected. And SC1 and SC2 are output.

Next, the optical disk recording / reproducing apparatus of this embodiment including the PU 10 will be described with reference to FIG.
As shown in FIG. 5 described above, the PU 10 divides the laser beam into a main beam RA and two side beams RB and RC, and irradiates the groove G on the optical disc 6 and two adjacent lands LB and LC, respectively. Then, the reflected light is detected and the detection signals SA1 to SA4 of the groove G and the detection signals SB1, SB2, SC1, and SC2 of the lands LB and LC are output. The detection signals SA1 to SA4 of the groove G are sent to the reproduction signal detection circuit 11, the focus error detection circuit 12, the tracking error detection circuit 13 and the wobble signal detection circuit 200, respectively, and the detection signals SB1 and SB2 of the land LB and the detection of the land LC are detected. The signals SC1 and SC2 are sent to the tracking error detection circuit 13 and the phase shift detection circuit 100, respectively.

  The reproduction signal detection circuit 11 detects the reproduction signal by the calculation of (SA1 + SA2 + SA3 + SA4). The detected reproduction signal is sent to a reproduction signal processing circuit (not shown) and then output as reproduction information. The focus error detection circuit 12 detects a focus error signal by the calculation of (SA1 + SA3) − (SA2 + SA4), and the tracking error detection circuit 13 is (SA1 + SA2-SA3-SA4) −k (SB1−SB2 + SC1−SC2) (k is a constant). ) To detect a tracking error signal by a D-PP (differential push-pull) method. The detected focus error signal and tracking error signal are sent to a servo circuit (not shown) and used for focus control and tracking control of the PU 10.

  In the wobble signal detection circuit 200, the wobble signal WA is extracted by the calculation circuit 201 that performs the calculation of (SA1 + SA2−SA3−SA4) and the BPF (bandpass filter) 202, and is sent to the binarization circuit 203 and the phase shift detection circuit 100. . The binarization circuit 203 binarizes the wobble signal WA and then outputs the binarized wobble signal to the clock generation circuit 300.

  The phase shift detection circuit 100 uses the wobble signal WA, the detection signals SB1 and SB2 of the land LB, and the detection signals SC1 and SC2 of the land LC, and the phase of the wobble of the groove irradiated by the main beam RA and the wobble of the adjacent groove. The deviation is detected, which will be described in detail below.

  First, a configuration example of the phase shift detection circuit 100 in the optical disc recording / reproducing apparatus of the present embodiment will be described with reference to FIG.

  As shown in FIG. 6, the first radial push-pull signal detection circuit (first R-PP signal detection circuit) 101 calculates a difference (SB1−SB2) between the detection signals of the land LB, and calculates the first radial push-pull signal PB. Output to the delay circuit 103. The second radial push-pull signal detection circuit (second R-PP signal detection circuit) 102 calculates the difference (SC1−SC2) between the detection signals of the land LC and outputs the second radial push-pull signal PC to the addition circuit 104. . The delay circuit 103 corrects a time lag between the first radial push-pull signal PB and the second radial push-pull signal PC caused by a difference in irradiation position of the side beam RB and the side beam RC on the optical disc, and the second radial push-pull signal PC is corrected. The first radial push-pull signal after synchronization synchronized with the push-pull signal is sent to the adder circuit 104. The adder circuit 104 adds the first radial push-pull signal and the second radial push-pull signal PC after synchronization, and sends the addition signal to a BPF (band pass filter) 105. The BPF 105 extracts a signal component corresponding to the wobble frequency from the addition signal 104 and sends the wobble component extraction signal to the amplifier 106. The amplifier 106 amplifies the wobble component extraction signal with a predetermined amplification factor, and then sends the amplified wobble component extraction signal WS to the second amplitude detection circuit 108. Here, the amplification factor in the amplifier 106 is set so that the amplitude of the wobble component extraction signal is the same as the amplitude of the wobble signal when there is no phase shift between the wobble of the groove and the wobble of the adjacent groove. When the wobble component extraction signal has the maximum amplitude when there is no phase shift between the groove wobble and the adjacent groove wobble, the amplitude of the wobble signal is the same as the amplitude of the wobble signal when the wobble component extraction signal has the maximum amplitude. It is only necessary to set an appropriate amplification factor.

  The first amplitude detection circuit 107 detects the magnitude of the amplitude of the wobble signal output from the wobble signal detection circuit (200 in FIG. 1) as an amplitude value MA, and outputs it to the amplitude ratio detection circuit 109. The second amplitude detection circuit 108 detects the amplitude of the amplified wobble component extraction signal WS as an amplitude value MS, and outputs it to the amplitude ratio detection circuit 109. The amplitude ratio detection circuit 109 calculates the ratio of the amplitude value MS of the amplified wobble component extraction signal WS to the amplitude value MA of the wobble signal WA as MS / MA, and outputs it as phase shift information.

  Here, the principle of the phase shift detection circuit 100 (FIG. 6) will be described with reference to FIGS. Each signal shown in FIGS. 7 to 10 is shown in a time-synchronized state for convenience of explanation. As shown in FIG. 7, when there is no phase shift from the wobble of the adjacent groove, that is, when the wobble of the adjacent groove has the same phase, it is included in the wobble signal WA of the groove G and the radial push-pull signal PB of the land LB. The wobble component included in the radial push-pull signal PC of the land LC is detected as a signal as shown in FIG. 7A, FIG. 7B, and FIG. 7C, respectively. In this case, the wobble components of the two radial push-pull signals PB and PC have the same phase, and the amplified wobble component extraction signal WS based on the added signal is detected as a signal as shown in FIG. . In this case, the amplitude of the amplified wobble component extraction signal WS is set to be the same as the amplitude of the wobble signal WA by the amplifier 106 described above.

  On the other hand, when the wobble phase of the adjacent groove is shifted by + π / 2 as shown in FIG. 8, the amplitude of the wobble signal WA is the same as that of the wobble described above as shown in FIG. Although almost the same as the case, the amplitude of the wobble component of the radial push-pull signal PB and the wobble component of the radial push-pull signal PC becomes smaller as shown in FIGS. 8B and 8C, respectively. The phases of the two wobble components become different. As a result, the amplified wobble component extraction signal WS based on the added signal has a smaller signal amplitude as shown in FIG. 8D, and is about ½ the amplitude of the wobble signal WA. Also, as shown in FIG. 9, when the wobble phase of the adjacent groove is shifted by −π / 2, each signal becomes as shown in FIGS. 9A to 9D, and the wobble phase described above becomes + π / Similar to the case of two deviations, the amplitude of the amplified wobble component extraction signal WS is about ½ of the amplitude of the wobble signal WA.

  Furthermore, when the wobble phase of the adjacent groove is shifted by + π (or π) as shown in FIG. 10, that is, in the opposite phase, the amplitude of the wobble signal WA is almost as shown in FIG. Although not changed, the wobble component of the radial push-pull signal PB and the wobble component of the radial push-pull signal PC are hardly detected as shown in FIGS. 10B and 10C, respectively. The amplified wobble component extraction signal WS thus made is hardly detected as shown in FIG. 10 (d), and its amplitude value is almost zero.

  In this way, the amplified wobble component extraction signal WS has a relationship in which the signal amplitude decreases as the wobble phase shift with the adjacent groove increases. Therefore, by detecting the magnitude of the amplitude of the amplified wobble component extraction signal WS, it is possible to detect the amount of wobble phase shift with the adjacent groove. However, if the signal amplitude is simply detected, the signal amplitude may fluctuate due to other factors such as laser power fluctuation and defocus. The problem of detection is likely to occur. Therefore, the present invention further utilizes the fact that the amplitude of the wobble signal WA is substantially constant regardless of the wobble phase shift with the adjacent groove, and the amplitude value MS of the amplified wobble component extraction signal WS is the same as that of the wobble signal WA. The ratio to the amplitude value MA is detected.

  Since the ratio of the amplitude value MS of the amplified wobble component extraction signal to the amplitude value MA of the wobble signal is substantially proportional to the amount of wobble phase shift with the adjacent groove as shown in FIG. 14, this ratio is detected. Thus, the amount of phase shift can be detected. In this case, the amplitude fluctuation due to laser power fluctuation or defocus is included in both the wobble signal WA and the amplified wobble component extraction signal MS, so that the fluctuation can be removed by taking the ratio. Thus, it is possible to prevent a detection error of the phase shift amount.

Hereinafter, returning to FIG. 1, the remaining portion will be described.
In the clock generation circuit 300, the wobble signal phase comparator 310 compares the phase of the binarized wobble signal with the wobble synchronization clock output from the frequency divider 302, and uses the comparison result as a wobble phase difference signal as a VCO (oscillation circuit). ) 301.

Here, the wobble signal phase comparator 310 includes, for example, a rising phase comparator 311, a falling phase comparator 312, an adder 313, and an LPF (low pass filter) 314 as shown in FIG. The rising phase comparator 311 compares the phase difference between the rising edge of the binarized wobble signal and the rising edge of the wobble synchronization clock, and the falling phase comparator 312 is synchronized with the falling edge of the binarized wobble signal and the wobble synchronization. The phase difference with the falling edge of the clock is compared, and the rising phase difference signal and the falling phase difference signal are output to the adder 313, respectively. The adder 313 adds the two phase difference signals output from the rising phase comparator 311 and the falling phase comparator 312 and sends it to the LPF 314. The LPF 314 smoothes the phase difference signal after addition sent from the adder 313 and then outputs it as a wobble phase difference signal (to the VCO 301 in FIG. 1).
Returning to FIG. 1, the clock generation control circuit 110 executes the phase comparison operations of the rising phase comparator 311 and the falling phase comparator 312 shown in FIG. 11 in accordance with the phase shift information output from the phase shift detection circuit 100. Specific operations will be described below.

  As shown in FIG. 2, when the wobble phase shift from the adjacent groove is + π / 2, the adjacent groove approaches the rising slope portion of the wobble, so that the rising edge of the extracted wobble signal has a large phase fluctuation due to the influence of crosstalk. Become. On the other hand, since the adjacent groove is far from the falling slope portion of the wobble, the falling edge of the wobble signal is less affected by crosstalk and has less phase fluctuation. Therefore, the binarized wobble signal includes a large jitter at the rising edge as shown in FIG. In such a case, the clock generation control circuit 110 can generate an accurate clock by generating the recording clock and the rotation control clock using only the falling edge of the wobble signal after binarization. The operation of the rising phase comparator 311 is stopped. However, in actuality, not only when the wobble phase shift is + π / 2 but also in the vicinity thereof, it is affected by the crosstalk from the adjacent groove, so that the wobble phase shift is relatively large due to the crosstalk. + Π / 2 ± In the case of π / 8, the clock generation control circuit 110 performs control so that the operation of the rising phase comparator 311 is stopped.

  In addition, when the phase shift is −π / 2 as shown in FIG. 3, the adjacent groove approaches the falling slope portion of the wobble, so that the falling edge of the extracted wobble signal has a large phase fluctuation due to the influence of crosstalk. Become. On the other hand, since the adjacent groove is far from the rising slope portion of the wobble, the rising edge of the wobble signal is less affected by crosstalk and has less phase fluctuation. Therefore, the binarized wobble signal includes a large jitter at the falling edge as shown in FIG.

  In such a case, it is possible to generate an accurate clock by using only the rising edge of the binarized wobble signal to generate the recording clock and the rotation control clock. The operation of the falling phase comparator 312 is stopped. However, in actuality, not only when the wobble phase shift is −π / 2, but also in the vicinity thereof, it is affected by the crosstalk from the adjacent groove. In the case of 2 ± π / 8, the clock generation control circuit 110 performs control so that the operation of the falling phase comparator 312 is stopped.

  The VCO 301 generates a recording clock based on the wobble phase difference signal and outputs it to the recording data generation circuit 15 and the frequency divider 302. The frequency divider 302 divides the recording clock into 1 / s based on a predetermined proportional relationship fc = sxfw (s is a constant) between the wobble signal frequency fw and the recording clock frequency fc, and the wobble signal and period Are generated and output to the wobble phase comparator 310 and the rotation error detection phase comparator 18.

  The rotation error detection phase comparator 18 compares the reference clock from the reference clock generation circuit 19, that is, the phase difference between the clock of the predetermined wobble signal frequency fw and the wobble synchronization clock, and uses the comparison result as a rotation error signal for the motor. This is sent to the drive circuit 20. Based on the rotation error signal, the motor drive circuit 20 controls the rotation of the motor 21 so that the frequency of the wobble synchronization clock becomes the wobble signal frequency fw.

  The recording data generation circuit 15 generates recording data based on the recording clock and the recording information sent via the CPU 14 and outputs the recording data to the laser driving circuit 16. The power control circuit 17 controls the laser drive circuit 16 so that the recording power or the reproduction power is based on the power setting value sent from the CPU 14. The laser drive circuit 16 generates a laser drive signal based on the recording data from the recording data generation circuit 15 and the recording power controlled by the power control circuit 17 at the time of recording, and at the reproduction power controlled by the power control circuit 17 at the time of reproduction. A laser driving signal is generated. The laser 1 of the PU 10 is driven by this drive signal, and recording or reproduction on the optical disk 6 is performed.

  As described above, the above-described optical disk recording / reproducing apparatus can accurately detect the phase shift amount between the wobble of the groove and the wobble of the adjacent groove, and can accurately rotate the disk even when the crosstalk from the adjacent groove is large. It becomes possible to generate a control clock and a recording clock accurately synchronized with the rotation of the disk, and a good recording / reproducing signal can be obtained.

Next, the most preferred embodiment of the optical disk reproducing apparatus according to the present invention will be described with reference to the accompanying drawings.
FIG. 15 is a block diagram of an optical disk reproducing apparatus according to the second embodiment of the present invention. Note that the PU 10, the phase shift detection circuit 100, and the clock generation circuit 300 have the same configuration as that of the first embodiment, and therefore the details are omitted.

  As described with reference to FIG. 4 and FIG. 5, the PU 10 splits the laser beam into the main beam RA and the two side beams RB and RC, and on the groove G on the optical disc 6 and the two adjacent lands LB and LC. Each is irradiated, the reflected light is detected, and detection signals SA1 to SA4 of the groove G and detection signals SB1, SB2, SC1, and SC2 of the lands LB and LC are output. The detection signals SA1 to SA4 of the groove G are sent to the reproduction signal detection circuit 11, the focus error detection circuit 12, the tracking error detection circuit 13 and the wobble signal detection circuit 200, respectively, and the detection signals SB1 and SB2 of the land LB and the detection of the land LC are detected. The signals SC1 and SC2 are sent to the tracking error detection circuit 13 and the phase shift detection circuit 100, respectively.

The reproduction signal detection circuit 11 detects the reproduction signal by the calculation of (SA1 + SA2 + SA3 + SA4). The detected reproduction signal is sent to a reproduction signal processing circuit (not shown) and then output as reproduction information. The focus error detection circuit 12 detects the focus error signal by the calculation of (SA1 + SA3) − (SA2 + SA4), and the tracking error detection circuit 13 is (SA1 + SA2-SA3-SA4) −k (SB1−SB2 + SC1−SC2) (k is a constant). ) To detect a tracking error signal by a D-PP (differential push-pull) method. The detected focus error signal and tracking error signal are sent to a servo circuit (not shown) and used for focus control and tracking control of the PU 10.
In the wobble signal detection circuit 200, the wobble signal WA is extracted by the calculation circuit 201 that performs the calculation of (SA1 + SA2−SA3−SA4) and the BPF (bandpass filter) 202, and is sent to the binarization circuit 203 and the phase shift detection circuit 100. . The binarization circuit 203 binarizes the wobble signal WA and then outputs the binarized wobble signal to the clock generation circuit 300.
As described with reference to FIG. 6, the phase shift detection circuit 100 uses the wobble signal WA, the detection signals SB1 and SB2 of the land LB, and the detection signals SC1 and SC2 of the land LC to detect the groove irradiated by the main beam RA. A phase shift between the wobble and the wobble of the adjacent groove is detected.

The clock generation circuit 300 compares the phase of the binarized wobble signal and the wobble synchronization clock output from the frequency divider 302 by the wobble signal phase comparator 310 described with reference to FIG. The phase difference signal is output to a VCO (oscillation circuit) 301.
The clock generation control circuit 110 executes / stops the phase comparison operations of the rising phase comparator 311 and the falling phase comparator 312 shown in FIG. 11 according to the phase shift information output from the phase shift detection circuit 100, respectively. Specifically, when the wobble phase shift is + π / 2 ± π / 8, the operation of the rising phase comparator 311 is stopped, and when the wobble phase shift is −π / 2 ± π / 8, the falling phase comparator The operation of 312 is stopped.

The VCO 301 generates a clock based on the wobble phase difference signal and outputs it to the frequency divider 302. The frequency divider 302 divides the VCO output clock by 1 / s based on the predetermined proportional relationship fv = sxfw (s is a constant) between the wobble signal frequency fw and the VCO output clock frequency fv. Are generated and output to the wobble phase comparator 310 and the rotation error detection phase comparator 18.
The rotation error detection phase comparator 18 compares the reference clock from the reference clock generation circuit 19, that is, the phase difference between the clock of the predetermined wobble signal frequency fw and the wobble synchronization clock, and uses the comparison result as a rotation error signal for motor This is sent to the drive circuit 20. Based on the rotation error signal, the motor drive circuit 20 controls the rotation of the motor 21 so that the frequency of the wobble synchronization clock becomes the wobble signal frequency fw.
The power control circuit 17 controls the laser drive circuit 16 so that the reproduction power is based on the power setting value sent from the CPU 14. The laser drive circuit 16 generates a laser drive signal with the reproduction power controlled by the power control circuit 17. The laser 1 of the PU 10 is driven by this drive signal, and information on the optical disk 6 is reproduced.
As described above, it is possible to accurately detect the phase shift amount between the wobble of the groove and the wobble of the adjacent groove by the detailed optical disk reproducing apparatus, and it is possible to accurately rotate the disk even when the crosstalk from the adjacent groove is large. A control clock can be generated, and a good reproduction signal can be obtained.

  In the above description, when the phase shift is + π / 2 ± π / 8 by the clock generation control circuit 110, the operation of the rising phase comparator 311 is stopped, and when the phase shift is −π / 2 ± π / 8, the falling phase is stopped. Although the operation of the comparator 312 is stopped, the rising phase comparator 311 or the falling phase comparator 312 is within the range including + π / 2 ± π / 4 and −π / 2 ± π / 4, respectively. The operation may be stopped.

1 is a configuration diagram of an optical disc recording / reproducing apparatus according to a first embodiment of the present invention. It is a figure which shows typically the location from which the wobble phase shift between adjacent grooves becomes + (pi) / 2. It is a figure which shows typically the location from which the wobble phase shift | offset | difference between adjacent grooves becomes-(pi) / 2. It is a figure which shows the irradiation position on the optical disk of the main beam and two side beams in this invention. It is a block diagram of the optical pick-up in this invention. It is a figure which shows the structural example of the phase shift detection circuit in this invention. It is a figure which shows each detection signal in case the wobble phase of a groove adjacent to a groove is the same phase. It is a figure which shows each detection signal in case the wobble phase of a groove adjacent to a groove | channel has shifted | deviated + pi / 2. It is a figure which shows each detection signal in case the wobble phase of a groove adjacent to a groove | channel has shifted | deviated -pi / 2. It is a figure which shows each detection signal in case the wobble phase of a groove adjacent to a groove is an antiphase. It is a figure which shows the structural example of the wobble signal phase comparison circuit in this invention. It is a figure which shows the binarized wobble signal when the wobble phase shift between adjacent grooves becomes + π / 2. It is a figure which shows the binarized wobble signal when the wobble phase shift between adjacent grooves becomes -π / 2. It is a figure which shows the relationship between the amplitude ratio of a wobble signal and a wobble component extraction signal, and a phase shift amount. It is a block diagram of the optical disk reproducing | regenerating apparatus which is the 2nd Example of this invention.

Explanation of symbols

6 Optical disc 100 Phase shift detection circuit 101 First R-PP signal detection circuit (first radial push-pull signal detection means)
102 Second R-PP signal detection circuit (second radial push-pull signal detection means)
103 Delay circuit (synchronization means)
104 Adder circuit (addition means)
105 BPF (band pass filter) (filter means)
106 Amplifier (amplifying means)
107 first amplitude detection circuit (first amplitude detection means)
108 Second amplitude detection circuit (second amplitude detection means)
109 Amplitude ratio detection circuit (amplitude ratio detection means)
110 Clock generation control circuit (clock generation control means)
200 Wobble signal detection circuit (wobble signal detection means)
300 Clock generation circuit (clock generation means)
301 VCO (oscillation circuit)
302 Divider 310 Wobble signal phase comparator 311 Rising phase comparator 312 Falling phase comparator G Groove LB, LC Land RA Main beam RB, RC Side beam

Claims (4)

For an optical disc having an information recording groove and land wobbled at a predetermined frequency, a main beam is adjacent to the information recording groove, and two side beams are adjacent to the inner and outer peripheral sides of the information recording groove. In the optical disc recording / reproducing apparatus for recording / reproducing information by irradiating each of the lands,
Wobble signal detection means for detecting a wobble signal based on a detection signal reflected from the information recording groove and obtained from the main beam;
After correcting and adding the time lag of the first and second radial push-pull signals obtained from the side beams reflected by the lands adjacent to the inner and outer peripheral sides of the information recording groove, A signal corresponding to the wobble component of the information recording groove is extracted, the extracted signal is amplified, the amplitude of the wobble signal is detected, and the amplitude of the extracted and amplified signal and the amplitude Detecting a ratio between the amplitude of the wobble signal and detecting a phase shift between the wobble signal and the wobble signal of the adjacent groove;
A clock generating means for generating a recording clock and an optical disc rotation control clock using either one or both of rising and falling edges of the wobble signal;
Clock generation control means for controlling the clock generation means according to the phase deviation information detected by the phase deviation detection means;
An optical disc recording / reproducing apparatus comprising: The phase shift detection means detects a phase shift of + π / 2 when the wobble of the adjacent group is closest to the wobble rising slope portion of the information recording groove, and detects the phase shift of the wobble falling slope portion of the information recording groove. It is set to detect a phase shift of -π / 2 when the adjacent group wobble is closest.
The clock generation control means generates the optical disk rotation control clock using the falling edge of the wobble signal in the range where the phase shift includes at least + π / 2 ± π / 8, or the recording clock And the optical disk rotation control clock is generated so that the optical disk rotation is performed using the rising edge of the wobble signal in a range where the phase shift includes at least −π / 2 ± π / 8. Generating a control clock, or controlling the clock generation means to generate the recording clock and the optical disc rotation control clock;
The optical disk recording / reproducing apparatus according to claim 1. For an optical disc having an information recording groove and land wobbled at a predetermined frequency, a main beam is adjacent to the information recording groove, and two side beams are adjacent to the inner and outer peripheral sides of the information recording groove. In an optical disk reproducing apparatus for reproducing information by irradiating each of the lands,
After correcting and adding the time lag of the first and second radial push-pull signals obtained from the side beams reflected by the lands adjacent to the inner and outer peripheral sides of the information recording groove, A signal corresponding to the wobble component of the information recording groove is extracted, the extracted signal is amplified, the amplitude of the wobble signal is detected, and the amplitude of the extracted and amplified signal and the amplitude Detecting a ratio between the amplitude of the wobble signal and detecting a phase shift between the wobble signal and the wobble signal of the adjacent groove;
A clock generating means for generating a recording clock and an optical disc rotation control clock using either one or both of rising and falling edges of the wobble signal;
A clock generating means for generating an optical disk rotation control clock using either one or both of rising and falling edges of the wobble signal;
Clock generation control means for controlling the clock generation means according to the phase deviation information detected by the phase deviation detection means;
An optical disc reproducing apparatus comprising: The phase shift detection means detects a phase shift of + π / 2 when the wobble of the adjacent group is closest to the wobble rising slope portion of the information recording groove, and detects the phase shift of the wobble falling slope portion of the information recording groove. It is set to detect a phase shift of -π / 2 when the adjacent group wobble is closest.
The clock generation control means generates the optical disk rotation control clock using the falling edge of the wobble signal in the range where the phase shift includes at least + π / 2 ± π / 8, or the recording clock And the optical disk rotation control clock is generated so that the optical disk rotation is performed using the rising edge of the wobble signal in a range where the phase shift includes at least −π / 2 ± π / 8. Generating a control clock, or controlling the clock generation means to generate the recording clock and the optical disc rotation control clock;
4. An optical disk reproducing apparatus according to claim 3, wherein

Images