JPH1153745A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably access even an optical disk whose guide groove is not optimum in depth by switching a control target of focus control with a guide groove depth. SOLUTION: When the optical disk 11 is for a laser wavelength 780 nm, since it becomes deep groove equivalent for an optical disk device 10, the optimum focus control setting a just focal position in the control target is performed at a block error rate, and the optimum focus control setting the position offset to the optical disk 11 side by the deep groove equivalent much is performed at an address error rate. Further, though a signal ADIP of a fixed envelop is obtained in this offset position, the signal ADIP that the envelop is wobbled is detected in the just focus position. Thus, in this optical disk 11, a servo circuit 20 selects the reference voltage making this offset optimum position the control target in addition to recording data reproduction, and focus controls to the offset control target.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device, and more particularly, to an optical disk device that accesses an optical disk based on a guide groove formed in the optical disk. The present invention enables stable access to an optical disc in which the depth of a guide groove is displaced from an optimum depth by switching a control target of focus control in accordance with the depth of a guide groove. .

[0002]

2. Description of the Related Art Conventionally, in an optical disk apparatus for accessing this kind of optical disk, tracking control and spindle control are performed with reference to a groove formed on the optical disk, and address data of a laser beam irradiation position is detected. ing.

That is, as shown in FIG. 11, in this type of optical disc 1, a track is formed spirally from the inner circumference to the outer circumference, and as shown by a reference numeral A, this track is formed by a laser beam. Formed by the guide groove. In the mini-disc, the groove is formed to meander at a track pitch TP = 1.6 [μm], and the basic period TW of the meander is about 54 [μ].
m]. Further, the mini-disc is formed so that the groove is meandered by a predetermined frequency modulated signal, so that the address data of the laser beam irradiation position can be detected with reference to the groove.

In response to such an optical disk configuration,
The optical disk device irradiates a laser beam to the optical disk via an objective lens and receives the return light to generate a tracking error signal whose signal level changes according to the tracking error amount. Also, the optical disc apparatus generates a wobble signal whose signal level changes according to the meandering of the groove and a focus error signal whose signal level changes according to the focus error amount from the return light. A reproduction signal whose signal level changes according to the polarization plane of light is generated.

[0005] Among them, the optical disk device moves the objective lens in the radial direction of the optical disk so that the tracking error signal becomes a predetermined signal level, thereby performing tracking control based on the groove. Further, the objective lens is displaced along the optical axis so that the signal level of the focus error signal becomes a predetermined signal level, thereby performing focus control so as to perform just focus. Further, the rotation speed of the spindle motor is controlled so that the center frequency of the wobble signal becomes a predetermined frequency, whereby the optical disk is rotationally driven on the basis of the groove under the condition of a constant linear velocity.

Further, the optical disk device inputs the wobble signal to a detection circuit and detects address data from the frequency demodulated signal. The optical disk device specifies the laser beam irradiation position from the address data, intermittently raises the amount of the laser beam, applies a predetermined modulation magnetic field to the laser beam irradiation position, and thereby obtains a desired groove based on the groove. The data is thermomagnetically recorded.

On the other hand, at the time of reproduction, the data recorded on the optical disk is reproduced by utilizing the magnetic Kerr effect by binarizing the reproduced signal and performing digital signal processing.

In the optical disk formed so as to be accessible on the basis of the groove, the depth of the groove is λ / λ with respect to the wavelength λ of the laser beam.
It is manufactured in the range of 7 to λ / 9, whereby the spindle control can be reliably performed, and the address data and desired data can be reliably reproduced.

That is, as shown in FIG. 12 (B), the error rate of the reproduced data obtained from the reproduced signal (indicated here by the block error rate in units of interleave processing) varies depending on the depth of the groove. Instead, the error rate is maintained at a certain value or less within a certain range around the just focus position. Thus, in the optical disk device, when data is reproduced, focus control is performed so as to perform just focus, and desired data can be surely reproduced.

However, as shown in FIG. 12A, the error rate of the address data reproduced from the groove is:
It changes depending not only on the defocus amount but also on the depth of the groove. That is, when the depth of the groove is λ / 8, focus control is performed so that just-focus is performed as in the case of a reproduction signal, and address data can be reproduced in an optimal state. In other words, in the case of the depth λ / 8, the curve of the address error rate shows a characteristic symmetrical with respect to the defocus amount with the just focus position as the center, whereby it can be determined that the depth is optimal. However, when the depth of the groove becomes λ / 6, there is almost no room for reproducing address data in the just-focus state.

If there is no room for reproducing the address data as described above, there may occur a case where the address data cannot be correctly reproduced from the groove, whereby the laser beam irradiation position cannot be specified correctly. Further, when the wobble signal in such a case is observed, it is difficult to stably control the spindle because the envelope of the wobble signal is meandering.

From these facts, in this type of optical disk, the depth of the groove relative to the laser wavelength λ is set so that the error rate of the address data is maximized near the just focus where the error rate of the reproduced data is maximized. Is set in the range of λ / 7 to λ / 9.

[0013]

In a conventional optical disk apparatus for accessing a mini disk, a laser beam having a wavelength of 780 [nm] is applied to the optical disk. It is considered that if the wavelength of the laser beam is shortened, desired data can be recorded and reproduced at a higher density.

In this case, in the optical disk, it is necessary to reduce the depth of the groove by an amount corresponding to the shortened wavelength as compared with the prior art so that address data can be reproduced stably and spindle control can be performed stably. . That is, in an optical disk applied to such an optical disk device having a short laser wavelength, for example, the laser wavelength is 650.
In the case of [nm], it is required that the depth of the groove be 650/780 times that of the conventional optical disk.

[0015] Even in such a case, it is considered that if the conventional optical disk can be accessed in the optical disk apparatus having a short laser wavelength, the past assets can be effectively used, which is convenient. In other words, it would be convenient if optical disk compatibility could be achieved between an optical disk device having a short laser wavelength and an optical disk device having a long laser wavelength.

However, if compatibility is attempted for optical disks having different laser wavelengths as described above, there is a problem in an optical disk apparatus that it is difficult to access the optical disk stably and reliably.

That is, for example, a laser wavelength of 780 [n
When the optical disk for [m] is accessed with a laser wavelength of 650 [nm], a groove formed in a depth range of [lambda] / 7 to [lambda] / 9 with respect to a laser wavelength of 780 [nm] becomes a laser wavelength of 650 [nm] ], The displacement is more than the optimum depth, and eventually the depth λ / 5.83-
λ / 7.5. As a result, when focus control is performed to perform just focus, although the block error rate can be sufficiently reduced, address data cannot be reproduced stably, and it is difficult to perform stable spindle control.

The present invention has been made in view of the above points, and it is an object of the present invention to propose an optical disk apparatus capable of stably accessing an optical disk in which the depth of a guide groove is displaced from an optimum depth. Things.

[0019]

According to the present invention, a control target for focus control is switched according to the depth of a guide groove.

At this time, when reproducing the data recorded on the optical disk, the control target of the focus control is set to the just focus position.

When reproducing the data recorded on the optical disk according to the depth of the guide groove, the rotation of the optical disk based on the meandering detection signal is changed to the rotation of the optical disk based on the processing result of the signal processing means. Switch to.

If the control target of the focus control is switched in accordance with the depth of the guide groove, even if the depth of the guide groove is displaced from the optimum depth, the optical disc is moved from the guide groove in accordance with the displacement. The optical disk can be accessed under the focus control condition that allows the beam irradiation position to be specified sufficiently accurately and that the spindle can be stably controlled.

At this time, when the data is reproduced, if the control target of the focus control is set to the just focus position, the data recorded on the optical disk is accessed by the focus control condition suitable for the reproduction of the data. be able to.

According to the depth of the guide groove, when reproducing data recorded on the optical disk, the optical disk is driven to rotate based on the meandering detection signal, and is rotated based on the processing result of the signal processing means. Thus, even when the control target of the focus control is set to the just focus at the time of data reproduction, spindle control can be stably performed.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a block diagram showing a recording system of the optical disk device according to the embodiment of the present invention. The optical disk device 10 is connected to information devices such as a computer, inputs and outputs various data D1 to and from the information devices, and stores the data D1 on the optical disk 11.

As shown in FIG. 3, the optical disk device 10 comprises a conventional mini disk having tracks formed at a track pitch of 1.6 μm, and a conventional mini disk having 0.95 μm.
m] so that various data can be recorded using a high-density mini-disc having tracks formed at a track pitch of [m]. These conventional and high-density mini-discs have the same outer shape consisting of the disc diameter and the disc thickness, differ in the laser wavelength of the applicable optical disc device and the numerical aperture NA of the optical pickup, The pitch and bit length are different. The mini-disc is housed in a predetermined cartridge and loaded into the optical disc device 10, and a concave portion formed in the cartridge allows discrimination between a conventional type and a high-density type.

FIG. 4 is a plan view showing this high-density optical disc in comparison with FIG. This optical disk 11
Has two grooves formed spirally from the inner peripheral side to the outer peripheral side. These two grooves are formed narrow,
This enables the high-density optical disk 11 to record desired data by so-called land recording.

Further, in this optical disk 11, one of these grooves is meandering.
The remaining one groove is formed so as not to meander. Thus, the optical disk 11 is formed so that the meandering detected by one groove can be shared by two tracks to detect an address and the spindle can be controlled, and the remaining groove reduces crosstalk between adjacent grooves. It has been done.

In the optical disk device 10, the data input unit 12 starts operating under the control of the control unit 13, and temporarily holds and outputs input data D1 input from an information device. The ID and EDC encoding unit 14 starts operation under the control of the control unit 13 to block the input data D1 input from the data input unit 12 in a predetermined data unit, and to execute an error detection code (EDC: Erro).
r Detecting Code) and identification data (ID).

The ECC encoder 15 starts its operation under the control of the controller 13. The ECC encoder 15 outputs an error correction code (ID) for each block with respect to the ID, the input data D1 output from the EDC encoder 14, and the error detection code. ECC:
Error Correcting Code) is added and output together with the identification data. The memory 16 starts operation under the control of the control unit 13, accumulates a predetermined amount of output data of the ECC encoding unit 15, performs interleaving processing at a predetermined timing, and outputs the result.

Under the control of the control unit 13, the modulation unit 17 performs EFM modulation on the output data of the memory 16, adds data such as a frame sync, and outputs the serial data. The magnetic field modulation driver 18 drives a modulation coil 19 according to the output data of the modulation section 17, and the modulation coil 19 applies a modulation magnetic field to a laser beam irradiation position where the light amount rises at a constant period during data recording. Thus, in the optical disk device 10, the input data D1 input from the information device is recorded on the optical disk 11.

That is, in the optical disk device 10, the servo circuit 20 controls the R
Based on various signals output from the F amplifier 21 and the like,
The optical pickup 22 performs tracking control, focus control, and sled control, and the spindle motor 23 performs spindle control.

The optical pickup 22 is movable in the radial direction of the optical disk 11 under the control of the thread of the servo circuit 20. Further, the optical pickup 22 irradiates the optical disk 11 with a laser beam, receives return light by a predetermined light receiving element, and outputs the light reception result. At this time, the optical pickup 22 irradiates the optical disk 11 with a laser beam having a wavelength of 650 [nm] via an objective lens having a numerical aperture of 0.52. In addition, the optical pickup 22 intermittently starts the light amount of the laser beam at a predetermined timing during recording.

FIG. 5 is a block diagram showing the relationship between the light receiving element in the optical pickup 22 and the RF amplifier 21. The optical pickup 22 irradiates the optical disk 11 with a laser beam via the diffraction grating, and outputs a −1st order,
The next and + 1st order return lights are respectively received by the light receiving elements 22-1 and 22-1
-2 and 22-3. Further, the polarization beam splitter separates the zero-order return light into two light beams whose light amount changes complementarily in accordance with the polarization plane of the return light, and receives the light beams by the light receiving elements 22-4 and 22-5, respectively.

As shown in FIGS. 6 and 7, in the high-density optical disk 11, when the 0th-order diffracted light by the diffraction grating is condensed on the track center TC by the land, the optical pickup 22 receives -1. An optical system is formed so that the next and + 1st order diffracted lights are focused on the inner and outer grooves of the track. Optical pickup 2
Reference numeral 2 denotes a light receiving element 22-1 and 22-3 for receiving these -1st order and + 1st order return light, the light receiving surface of which is divided in the radial direction of the optical disk 11 (the divided light receiving surfaces are denoted by reference numerals). E, F, G, and H), and a light receiving element 22-2 that receives the 0th-order return light is formed by dividing the light receiving surface into four in the radial direction and the circumferential direction of the optical disk 11 (each divided). The light receiving surfaces are indicated by reference numerals A to D).

The RF amplifier 21 performs a current-to-voltage conversion process on an output signal output from each light receiving surface of the optical pickup 22, and then amplifies and amplifies the operational signals using operational amplifier circuits 21A, 21B,. (Address ln Pre-groove) signal A whose signal level changes
DIP, a tracking error signal TE whose signal level changes according to the tracking error amount, a focus error signal FE whose signal level changes according to the focus error amount, and a reproduction signal MO whose signal level changes according to the polarization plane of the return light. Is output.

That is, the operational amplifier circuit 21A receives the light receiving surfaces G and H from the light receiving element 22-1 which receives the -1 order return light.
And the differential signal GH of the light receiving surfaces G and H
Is output. The operational amplifier circuit 21C receives the output signals of the light receiving surfaces E and F from the light receiving element 22-2 that receives the +1 order return light, and outputs a difference signal EF between the light receiving surfaces E and F.

The operational amplifier circuit 21B receives the output signals of the respective light receiving surfaces A to D from the light receiving element 22-2 for receiving the zero-order return light, and corresponds to the case where the light receiving surface is divided in the radial direction of the optical disk 11. Generate two sum signals A + D and B + C. Further, the operational amplifier 21B outputs the two sum signals A
A difference signal (B + C)-(A + D) between + D and B + C is generated. Further, the operational amplifier circuit 21B generates sum signals A + C and B + D between the light receiving surfaces in the diagonal direction and generates a difference signal (A + C)-(B + D) between the two sum signals A + C and B + D. A focus error signal FE is generated by the aberration method. The operational amplifier circuit 21B generates a difference signal IJ between the output signals I and J by the light receiving elements 22-4 and 22-5, and thereby generates a reproduction signal MO.

The operational amplifier 21D outputs the differential signal GH,
From EF and (B + C)-(A + D), the tracking error signal TE ((B + C)-(A + D) -k ((E-
F) + (GH)). Here, k is a predetermined constant. Further, the RF amplifier 21 outputs the differential signals GH, E
-F, the sum signals A + D, B + C are converted to ADIP (Address ln P
re-groove) Output as signal ADIP.

As described above, when the conventional optical disk 11 is accessed in the optical disk device 10, 0 is used.
When the tracking control of the laser beam is performed so that the next diffracted light is on-track to the track by the groove,-
The first-order and + 1st-order diffracted lights are condensed on the optical disc while being offset with respect to the adjacent groove. However, since this offset position is symmetrical with respect to the beam spot due to the zero-order diffracted light, the tracking error signal TE applied to the high-density optical disk 11 in this embodiment has The signal level of the optical disk also changes according to the tracking error amount. Also, in the focus error signal FE, the signal level changes according to the focus error amount with reference to the land surface and the bottom surface of the groove, respectively. In the ADIP signal ADIP, the sum signals A + D and B obtained from the 0-order return light
The signal level of the + C difference signal (A + D)-(B + C) changes according to the meandering of the groove in the conventional optical disc.

On the other hand, in the high-density optical disk 11, the difference signal GH or EF is selectively processed depending on which of the two tracks is accessed, and the address is obtained. The data can be detected. The track can be determined based on which of the difference signals GH and EF detects the meandering of the groove.

The ADIP signal demodulation section 24 (FIG. 2) performs FM detection of the ADIP signal ADIP according to this detection principle. The ADIP decoding unit 25 includes the ADIP signal demodulation unit 2
The address data AD is reproduced from the output signal of No. 4. The address data AD reproduced by the ADIP signal demodulation unit 24 is checked for errors and output.

That is, as shown in FIG. 8, under the control of the MPU 26, the ADIP signal demodulation section 24 separates the differential signals GH and EF from the band-pass filter (BPF) on the high-density optical disk 11. ) Band limitation by 24A and 24B. In the conventional optical disc 1, the sum signals A + D and B + C are band-limited by band-pass filters 24A and 24B, respectively. Subsequent subtraction circuit 2
4C subtracts the output signals of the band-pass filters 24A and 24B.
4C output signal is detected and the carrier signal ADI is detected.
Extract and output P. The ADIP decoding unit 25 demodulates the address data AD from the output signal of the FM detection circuit 24D in the biphase decoder 25A, and performs error correction processing in the subsequent error correction circuit 25B.

In the ADIP signal demodulation unit 24, the level detection comparator 24E includes band pass filters 24A and 24A.
By comparing the signal levels of B, the differential signal G-H
Alternatively, it is determined which of EF and groove meandering is detected, and a track determination signal SH based on the determination result is output.

The MPU (microprocessing unit) 26
The operation of the entire optical disk device 10 is controlled via the control unit 13 by communication with an external device. At this time, the MPU (microprocessing unit) 26 switches the entire operation mode according to the laser beam irradiation position specified by the address data AD, thereby recording the input data D1 in the unrecorded area of the optical disk 11, and recording the already recorded data. The input data D1 is overwritten and recorded in the area, and the desired data recorded on the optical disk 11 is reproduced. At this time, for the high-density optical disk 11, the MPU performs the track determination signal SH and the address data AD.
, The laser beam irradiation position is determined, and processing such as seek is executed as necessary.

When the input data D1 is processed and recorded on the optical disk 11, the optical disk drive 10
Then, the type of the optical disk 11 is determined by a determination signal output from a predetermined disk determination mechanism, and the timing of accessing the optical disk 11 is controlled based on the determination result. The input data D1 is recorded on the optical disk 11.

FIG. 9 is a block diagram showing a reproduction system of the optical disk device 10. Optical disk 11 from external equipment
When the reproduction of the data is instructed, the optical pickup device 10 seeks the optical pickup 22 under the control of the servo circuit 20, and starts reproducing the data recorded on the optical disk 11.

The RF signal demodulation circuit 30 starts its operation under the control of the control section 13, binarizes the reproduction signal MO output from the RF amplifier 21, and activates the PLL circuit with the resulting binarized signal. Drive, thereby generating a clock synchronized with the reproduction signal MO. Further RF
The signal demodulation circuit 30 sequentially latches the binarized signal by the clock, and thereby generates reproduced data. Further, the RF signal demodulation circuit 30 performs EFM demodulation on the reproduced data and outputs demodulated data.

The ID decoding section 31 reproduces the identification data ID from the demodulated data, and controls the address data in the memory 32 based on the reproduction result. The memory 32
The decoded data output from the RF signal demodulation circuit 30 is sequentially input by the address data control, and is output at a predetermined timing, so that the decoded data is deinterleaved and output.

The ECC decoding section 33 performs error correction processing on the output data of the memory 32 and outputs the same. The EDC decoding section 34 performs error detection processing on the output data and performs error correction processing as necessary and outputs the result. The data output unit 35
The output data of the DC decoding unit 34 is held for a certain period of time, and is transmitted after the external device acknowledges it. Thus, the optical disk device 10 reproduces and outputs data recorded on the optical disk 11.

FIG. 1 is a block diagram showing a spindle control system and a focus control system of the optical disk device 10. In the optical disc device 10, the disc discrimination mechanism 40 is composed of a plurality of switches for detecting a concave portion formed in the cartridge of the optical disc 11, and the contact outputs of these switches are used as the disc discrimination signal S1 as MP
Output to U26.

The MPU 26 receives the disc discrimination signal S1
If the optical disk 11 is of a high-density type, the operation of the focus control system is set so as to perform just focus, and the operation of the spindle servo system is set so as to control the rotation of the optical disk 11 by meandering of the groove.

On the other hand, when the optical disk 11 is a conventional type, the MPU 26 performs the just focus when reproducing data from the optical disk 11, and in other cases, the control target is set by the depth of the groove. The operation of the focus control system is set so as to be offset toward the optical disk 11. When data is reproduced from the optical disc 11, the frame sync S obtained from the optical disc 11 is used.
The operation of the spindle servo system is set so as to control the rotation of the optical disk 11 with reference to the YNC. In other cases, the operation of the spindle servo system is set so as to control the rotation of the optical disk 11 by meandering grooves. .

That is, the servo circuit 20 receives the predetermined reference voltages V0 and V1 to the selection circuit 20A and, under the control of the MPU 26, subtracts these reference voltages V0 and V1 from the subtraction circuit 2A.
Selectively output to 0B. The subtraction circuit 20B subtracts the focus error signal FE output from the RF amplifier 21 from the reference voltage V0 or V1 output from the selection circuit 20A, and outputs the result.
Moves the objective lens 22A of the optical pickup 22 along the optical axis of the laser beam L so that the output voltage of the subtraction circuit 20B becomes 0 level. Thus, the servo circuit 20 sets the reference voltage output from the selection circuit 20A as a control target, and performs focus control by a feedback loop.

Here, the first reference voltage V0 is maintained at a voltage of 0 [V] as shown in FIG. 10, so that the servo circuit 20 selects the first reference voltage V0 by the MPU 26. Focus control is performed so as to achieve just focus. Accordingly, when the optical disc 11 is of a high-density type, the address error rate and the block error rate (FIG. 10 (B) and FIG. 12 (B))
Focus control is performed according to the optimal conditions. When the optical disk 11 is of a conventional type, when reproducing data from the optical disk 11, the block error rate (FIG. 12) which is different from the optimal condition of the address error rate (FIG. 10B).
Focus control is performed under the optimum condition (B)).

On the other hand, the second reference voltage V1 is set such that the position shifted from the just-focused position of the objective lens 22A toward the optical disk 11 by a predetermined distance ΔL becomes the control target. Furthermore, this distance ΔL
Is a distance corresponding to the optimum condition of the address error rate in the conventional optical disc 11 (FIG. 10).
(B)). As a result, the servo circuit 20
1 is a conventional type, and when data is not reproduced from the optical disc 11, an address error rate (FIG. 10B) different from the optimal condition of the block error rate (FIG. 12B) is used.
Focus control is performed under the optimum condition (B)).

In the servo circuit 20, the first frequency divider (1 / N) 20D outputs the ADIP signal ADIP (F in FIG. 8).
The carrier signal output from the M detection circuit 24D is divided by a predetermined dividing ratio 1 / N and output. Further, the second frequency dividing circuit (1 / M) 20D divides the frame sync SYNC by a predetermined dividing ratio 1 / M and outputs the result. The selection circuit 20F switches contacts under the control of the MPU 26, and selectively outputs the output signal of the frequency dividing circuit 20D or 20E. The spindle servo circuit 20G compares the phase of the selection output of the selection circuit 20F with a predetermined reference signal so that the phase comparison result becomes 0 level, that is, the selection circuit 20F
The operation of the spindle motor 23 is controlled so that the selected output at the predetermined frequency becomes a predetermined frequency.

Thus, when the focus control is performed under the optimum condition of the address error rate (FIG. 10B), the selection circuit 20F outputs the output signal of the frequency dividing circuit 20D so that the spindle control is performed by the ADIP signal ADIP. Select output. That is, when the optical disk 11 is of a high-density type or when the optical disk 11 is of a conventional type and other than reproducing data from the optical disk 11, the ADIP signal A
Spindle control is performed based on DIP.

On the other hand, when the focus control is not performed under the optimum condition of the block error rate, the output signal of the selection circuit 20E is selectively output so that the spindle control is performed by the frame sync SYNC. That is, when the optical disk 11 is of a conventional type and data is reproduced from the optical disk 11, the spindle control is performed based on the frame sync SYNC.

In the above configuration, when the optical disk 11 is loaded (FIG. 1), the optical disk 11 is driven by the disk discriminating mechanism 40 by the concave portion formed in the cartridge and the high-density optical disk formed for the laser wavelength of 650 [nm]. Type or a conventional type formed for a laser wavelength of 780 [nm].

This optical disk 11 has a laser wavelength 65
In the case of the high-density type formed for 0 [nm], the block error rate when reproducing the recorded data and the address error rate of the address data due to the meandering of the groove (FIG. 10) are just focus. Since the optimal focus control can be executed by setting the position as the control target, in the optical disk device 10, the servo circuit 20 uses the reference voltage V of 0 [V].
0 is selected by the MPU 26, and focus control is performed by the focus error signal FE with the reference voltage V0 as a control target.

Since the focus control is performed on the address error rate under the optimum condition, the envelope of the ADIP signal ADIP obtained by detecting the meandering of the groove is output from the RF amplifier 21 while keeping the envelope almost constant. In the servo circuit 20, this A
The spindle control is performed so that the frequency of the DIP signal ADIP becomes a predetermined frequency.

With these processes, the optical disk device 10
With reference to address data AD obtained by demodulating the ADIP signal ADIP, input data D1 sequentially input is recorded on the optical disk 11 in a predetermined format, and the input data D1 recorded on the optical disk 11 is reproduced. It is output (FIGS. 2 to 9).

On the other hand, when the optical disk 11 is of a conventional type formed for a laser wavelength of 780 [nm], the groove is equivalently formed deeper in the optical disk device 10. In this case, with respect to the block error rate, the focus can be optimally controlled by setting the position of the just focus as the control target, and the address error rate is offset toward the optical disc 11 by the equivalent depth of the groove. Optimal focus control can be performed with the position as a control target (FIG. 10). At this offset position, an ADIP signal ADIP whose envelope is kept substantially constant can be obtained, whereas at the just-focused position,
An ADIP signal ADIP in which the envelope meanders is detected.

Thus, in the optical disk 11, the servo circuit 20 controls the MPU 26 to select the reference voltage V1 which is a control target of the offset optimum position except for reproducing data recorded on the optical disk 11. Then, focus control is performed on the control target offset by the reference voltage V1. Thus, in the optical disk 11, correct address data AD is reproduced from the ADIP signal ADIP, and when an access command is input from an external device, the optical pickup 22 is moved to a desired recording / reproducing position based on the reproduced address data. Is sought. The spindle is controlled based on the ADIP signal ADIP whose envelope is kept substantially constant.

When the optical pickup 22 seeks to a desired recording / reproducing position in the state where the spindle control is performed as described above, when a write command is input from an external device, the spindle control and the focus control perform The input data D1 input from the external device is thermomagnetically recorded on the optical disk 11.

On the other hand, when a read command is input from an external device, the optical disc device 10
The reference voltage V0 is selected, and focus control is performed so as to perform just focus. Thus, by the focus control most suitable for data reproduction, the reproduction signal MO output from the RF amplifier 21 is sequentially signal-processed, and the data D1 recorded on the optical disk 11 is reproduced and output to an external device. At this time, a frame sync SYNC obtained by performing signal processing on the reproduction signal MO is selected in the servo circuit 20, and the frame sync SYNC is selected.
Is controlled to a predetermined frequency. Thus, even when the envelope of the ADIP signal ADIP is meandering due to the optimum focus control of the data, the spindle control can be stably performed and the desired data can be reliably reproduced.

According to the above configuration, in the optical disk apparatus for accessing the high-density optical disk 11, when the conventional optical disk having a long laser wavelength is accessed, the focus control is performed by switching the control target of the focus control. The address data recorded in the groove can be reproduced stably and reliably, and the spindle control of the optical disk 11 can be performed stably and reliably. Thereby, the optical disk 11 can be accessed stably.

At the time of data reproduction, the control target is switched so as to perform just focus, and the reproduction signal MO is reproduced.
By performing spindle control on the basis of the frame sync which is the result of the above processing, data recorded on the optical disk 11 can be reproduced stably and reliably, and thereby the optical disk 11 can be accessed stably.

In the above-described embodiment, a case has been described in which two types of optical disks for optical disk devices having different laser wavelengths are accessed. However, the present invention is not limited to this. Also, the present invention can be applied to a case where the optical disc is displaced from the standard value, so that the optical disc can be accessed more stably. That is, in such an optical disc, when the focus control is performed so as to perform the just focus, the envelope of the ADIP signal ADIP is meandering. Thus, for example, A
By sequentially changing the control target of the focus control based on the envelope of the DIP signal ADIP, the optimum control target of the focus control can be detected. Therefore, when the data recorded on the optical disk 11 is not reproduced, the focus control is performed by the control target detected in this way, and when the data recorded on the optical disk 11 is reproduced, the focus control is performed so as to perform the just focus. Therefore, it is possible to access the optical disk more stably than before. In this case, if necessary, the reference of the spindle control may be switched in conjunction with the switching of the focus control, similarly to the above-described embodiment.

In the above-described embodiment, the case where spindle control is performed based on a frame sync obtained by processing a reproduction signal has been described. However, the present invention is not limited to this, and the present invention is not limited thereto. The spindle control may be performed on the basis of the reproduced clock to be used.

Further, in the above-described embodiment, the case where the tracks are formed spirally and the tracks are formed by grooves has been described. However, the present invention is not limited to this, and a plurality of tracks are formed in parallel and spirally. The present invention can be widely applied to a case where a track is formed by alternately switching a groove and a land, and a case where land-groove recording is used.

In the above embodiment, the case where the optical disk 11 is identified by the concave portion formed in the cartridge has been described. However, the present invention is not limited to this. For example, the case where the optical disk 11 is identified by TOC data or the like. Various disc discriminating methods can be widely applied.

In the above-described embodiment, the case where the focus control operation and the spindle control operation are switched for two types of optical disks has been described. However, the present invention is not limited to this, and a plurality of grooves having different groove depths are used. The present invention can also be applied to the case where compatibility is to be achieved for various types of optical disks.

Further, in the above-described embodiment, a case has been described in which a mini-disc made of a magneto-optical disc is accessed. However, the present invention is not limited to this. For example, a write-once optical disc, and further a phase-change optical disc As described above, the present invention can be widely applied when accessing an optical disk having a groove formed thereon.

Further, in the above-described embodiment, the case where address data is recorded by displacing the meandering of the groove by the frequency modulation signal has been described. However, the present invention is not limited to this, and the meandering of the groove is controlled by the phase modulation signal. The present invention can be widely applied to a case where an optical disc is accessed on the basis of a groove, such as a case where address data is recorded with displacement.

[0078]

As described above, according to the present invention, by switching the control target of the focus control in accordance with the depth of the guide groove, even an optical disk in which the depth of the guide groove is displaced from the optimum depth can be obtained. , Can be accessed stably.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a spindle control system and a focus control system of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a recording system of the optical disk device of FIG.

FIG. 3 is a table showing characteristics of an optical disk applied to the optical disk device of FIG. 1;

FIG. 4 is a plan view showing an optical disk applied to the optical disk device of FIG. 1;

FIG. 5 is a block diagram for explaining processing of a light reception result of the optical disk device of FIG. 1;

FIG. 6 is a plan view showing a relationship between the optical disk of FIG. 4 and a light receiving element.

7 is a plan view showing the relationship between the optical disc of FIG. 4 and the light receiving element in comparison with FIG.

8 is a block diagram for explaining processing of an ADIP signal of the optical disk device of FIG. 1;

FIG. 9 is a block diagram showing a reproduction system of the optical disk device of FIG.

FIG. 10 is a characteristic curve diagram for explaining switching of focus control of the optical disk device in FIG. 1;

FIG. 11 is a plan view showing a mini disc.

FIG. 12 is a characteristic curve diagram showing a relationship between a focus error and an error rate.

[Explanation of symbols]

1, 11 ... optical disk, 10 ... optical disk device, 2
0 ... servo circuit, 20A, 20F ... selection circuit, 20
B: Subtraction circuit, 20C: Focus servo drive, 20D, 20E: Frequency dividing circuit, 20G: Spindle motor servo, 21: RF amplifier, 22: Optical pickup, 23: Spindle motor, 24 ... ADI
P signal demodulation unit, 25 ADIP decoding unit, 26
MPU

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masato Tsujinaka Inside Sony Corporation 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo

Claims (13)

[Claims] 1. An optical disk device for irradiating a laser beam onto the optical disk with reference to a guide groove formed in the optical disk to access the optical disk, wherein: a disk drive means for driving the optical disk to rotate; A focus control unit configured to perform focus control of the laser beam based on a focus error signal obtained by receiving return light; and a control unit configured to switch a control target of the focus control according to a depth of the guide groove. An optical disc device characterized by the above-mentioned. 2. The optical disk apparatus according to claim 1, wherein said control means sets a control target of said focus control to a just-focus position when reproducing data recorded on said optical disk. 3. Receiving return light of the laser beam,
A light-receiving unit that outputs a meandering detection signal whose signal level changes according to the meandering of the guide groove and a reproduction signal whose signal level changes according to the amount of return light or the plane of polarization; and processes the reproduction signal. Signal processing means for reproducing data recorded on the optical disk, and the optical disk driving means, according to the depth of the guide groove, when reproducing the data recorded on the optical disk, the meandering detection signal 3. The optical disk apparatus according to claim 2, wherein the rotation drive of the optical disk based on the reference is switched to the rotation drive of the optical disk based on the processing in the signal processing unit. 4. The optical disk device according to claim 1, wherein said optical disk device has address data detecting means for detecting an irradiation position of said laser beam with reference to meandering of said guide groove. 5. The optical disc apparatus according to claim 4, wherein said control means sets a control target of said focus control to a just-focus position when reproducing data recorded on said optical disc. 6. Receiving return light of the laser beam,
A light-receiving unit that outputs a meandering detection signal whose signal level changes according to the meandering of the guide groove and a reproduction signal whose signal level changes according to the amount of return light or the plane of polarization; and processes the reproduction signal. Signal processing means for reproducing data recorded on the optical disk, and the optical disk driving means, according to the depth of the guide groove, when reproducing the data recorded on the optical disk, the meandering detection signal 6. The optical disk apparatus according to claim 5, wherein the rotation drive of the optical disk based on the reference is switched to the rotation drive of the optical disk based on the processing in the signal processing unit. 7. The optical disk device has an optical disk determination unit that determines the type of the optical disk and outputs an optical disk determination signal. The control unit sets a control target of the focus control in accordance with the optical disk determination signal. 2. The optical disk device according to claim 1, wherein the control target of the focus control is switched according to the depth of the guide groove by switching. 8. The optical disc apparatus according to claim 7, wherein said control means sets a control target of said focus control to a just-focus position when reproducing data recorded on said optical disc. 9. Receiving return light of the laser beam,
A light-receiving unit that outputs a meandering detection signal whose signal level changes according to the meandering of the guide groove and a reproduction signal whose signal level changes according to the amount of return light or the plane of polarization; and processes the reproduction signal. Signal processing means for reproducing data recorded on the optical disk, and the optical disk driving means, according to the depth of the guide groove, when reproducing the data recorded on the optical disk, the meandering detection signal 9. The optical disk device according to claim 8, wherein the rotation drive of the optical disk based on the reference is switched to the rotation drive of the optical disk based on the processing in the signal processing unit. 10. The control means switches a control target of the focus control according to a depth of the guide groove by switching a control target of the focus control based on a reception result of the return light. The optical disk device according to claim 1, wherein: 11. The optical disc apparatus according to claim 10, wherein said control means sets a control target of said focus control to a just-focus position when reproducing data recorded on said optical disc. 12. A meandering detection signal that receives return light of the laser beam and changes a signal level in accordance with meandering of the guide groove, and a signal level changes in accordance with a light amount or a polarization plane of the return light. A light-receiving unit that outputs a reproduction signal; and a signal processing unit that processes the reproduction signal to reproduce data recorded on the optical disk. Wherein when the data recorded on the optical disk is reproduced, the rotation driving of the optical disk based on the meandering detection signal is switched to the rotation driving of the optical disk based on the processing by the signal processing means. Item 11
An optical disk device according to claim 1. 13. An optical disk apparatus for accessing the optical disk by irradiating the optical disk with a laser beam with reference to a guide groove formed on an information recording surface, wherein the optical disk is accessed by performing focus control according to a predetermined control target. An optical disc apparatus, wherein when controlling access to the optical disc and an optical disc having a different depth of the groove, a control target of the focus control is switched.