JP2001034950A - Optical disc and optical disc recording playback apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disc which does not suffer the leak-in that the polarizing direction of a reflected light at grooves is affected by wobbles to thereby give influence on playback characteristics and is capable of surely generating synchronizing signals. SOLUTION: An optical magnetic disc 540 has grooves and lands, the grooves are structured such that grooves 551 have each a wobble 553 provided at either wall thereof and are followed at the back by zones where grooves 554 having no wobble and grooves 555 having no bobble at both sides are alternately disposed. As the result, the lands are structured such that lands 552 have wobbles 553 each provided at either wall thereof and is followed at the back by zones having no wobble.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk having a waveform pregroove, and more particularly to an optical disk suitable for a recording / reproducing apparatus for a recordable CD disk or a recordable magneto-optical disk, and a recording / reproducing apparatus therefor.

[0002]

2. Description of the Related Art In a mini disk, a groove having a waveform shape of a signal obtained by FM-modulating a carrier serving as a rotation synchronizing signal with address information is cut and used for rotation control and detection of address information. This method is generally called a wobbling method. Also, a wobbling method has been proposed in an optical disc apparatus in which recording is performed on a groove and a land between the grooves on an optical disc in which a groove having a waveform shape of a signal obtained by FM-modulating a carrier serving as a rotation synchronization signal with address information is formed. ing. In this case, as a method of reading address information, a laser beam emitted from a laser light source of an optical pickup is divided into a main beam and two sub beams by a diffraction grating.
As shown in FIG. 12, when the main beam is track-controlled around the center of the groove, address information is read from the push-pull signal from the main beam, and when the main beam is controlled around the land, as shown in FIG. A method of reading address information from a push-pull signal from a sub beam (Japanese Patent Laid-Open No. 7-14172) is known.

[0003]

In the above-mentioned conventional optical disk, the total length of the track is twice as large as that of the optical disk which is recorded only on the groove because the information is recorded on the groove and the land. However, since there is address information only in the groove, optical components such as a diffraction grating for dividing the laser beam emitted from the laser light source of the optical pickup into three beams of a main beam and two sub beams are required.
Another drawback is that the power of the laser beam emitted from the laser light source cannot be used effectively. In particular, in the case of a recordable optical disc, the efficiency of using the power of the laser beam is a major issue.

[0004] The present invention has been made in view of the above points, and an object of the present invention is not only to record address information recorded as a groove waveform, but also to use a
This enables reading with only one laser beam during recording and reproduction of lands, and reduces the number of optical components and sufficiently increases the recording density of the disk without impairing the power of the laser beam emitted from the laser light source. It is an object of the present invention to provide an optical disk recording / reproducing apparatus which can be increased in speed.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an optical disk capable of recording and reproducing data on a land and a groove, and a wobble including land and groove address information on one of the walls of the groove. Is established,
In a region other than a region where a wobble including the address information is provided, a region where a groove is not provided is periodically present.

In the present invention, the address information is recorded by a bi-phase modulation method. In the present invention, the address information is information common to a groove and a land. Further, the present invention comprises a land and a groove, a wobble including address information for the land and the groove is provided on one of the walls of the groove, and in an area other than the area where the wobble including the address information is provided, An optical disc recording / reproducing apparatus for recording / reproducing on / from an optical disc having a region where no groove is provided periodically, a magnetic head for applying a magnetic field to the optical disc, an optical unit for irradiating the optical disc with a laser beam, and the optical disc A synchronization signal generation circuit for generating a synchronization signal from a reproduction signal reproduced by the means, and the optical unit based on the synchronization signal generated by the synchronization signal generation circuit;
And a control circuit for controlling the magnetic head.

Further, in the present invention, the synchronization signal generation circuit generates a synchronization signal based on a reproduction signal from an area other than an area including the address information. Further, in the present invention, the synchronization signal generation circuit includes:
A comparator for binarizing the reproduction signal reproduced by the optical means, a PLL circuit for generating a timing pulse from the signal binarized by the comparator, and a predetermined circuit based on the timing pulse generated by the PLL circuit; A clock generation circuit for generating a synchronization signal composed of a clock.

Further, in the present invention, the photodetector in the optical means has a light receiving surface comprising a first area, a second area, a third area, and a fourth area, and A reproduction signal is obtained from an area other than the area including the address information by calculating the sum of the reflected light intensities of the laser beams detected on the optical disk in the second, third, and fourth areas. And

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 to 3, the magneto-optical disk 540 is divided into n zones 541,..., 54n from the inner periphery toward the outer periphery. , 6412,5
413,.., 541m, including m sectors, and the outer peripheral zone 54n includes 54n1, 54n2, 54n.
3,..., 54nl.
The number of sectors in each zone is determined so as to maximize the recording density, irrespective of whether they are the same or not.

FIG. 2 is a perspective view of a magneto-optical disk. The magneto-optical disk 540 has a groove and a land. The groove is formed with a groove 551 provided with a wobble 553 on one of the walls, and a region 554 where the groove is not provided behind the groove 551. In this structure, grooves 555 on which no wobbles are provided are alternately formed on the wall of the. As a result, the land is the land 5 in which the wobble 553 is provided on one of the walls.
52 are formed, followed by regions without wobble on both sides.

FIG. 3 is a plan view of the magneto-optical disk 540. In plan view, the groove G and the land L have a structure in which a wobble 553 is formed on one of them, and a region 554 in which no groove is provided is repeatedly formed at a constant interval. The area 554 is divided into four sectors.
Three are included. Therefore, in each of the sectors 5411, 5412, 5413,... Described with reference to FIG. 1, 43 regions 554 where no groove is formed are formed, and wobbles are provided at the head of each sector 5411, 5412, 5413,. It has a structure in which a groove 551 provided with 553 is formed.

The length 561 of the region where no wobble is provided on the walls on both sides is in the range of 50 to 150 μm, and the length 562 of the region 554 where no groove is provided is 0.5.
４4 μm. The length 563 of the area where the wobble 553 is provided is the same as the length 561. Further, the amplitude of the wobble 553 (where the amplitude is
It refers to the value from peak to peak. ) Is 60-150
nm range.

Accordingly, the magneto-optical disk 5 of the present invention
Numeral 40 is characterized in that groove and land address information are recorded in the wobble 553 by bi-phase modulation, and the areas 554 are formed at regular intervals. As a result, the wobble 553 includes address information common to lands and grooves located on both sides thereof. here,
The area 554 is used to generate a synchronization signal used for recording or reproducing a signal. Magneto-optical disk 54
0 sectors 5411, 5412, 5413,.
・ Until the laser beam reaches the area where
Since the wobble 553 is not provided, the laser beam detects an area 554 in which a groove that appears periodically is not formed (a detection method will be described later), and generates a synchronization signal from the detected signal.

In the above description, the wobble is provided on one wall of the groove. However, the present invention is not limited to this, and the wobble may be provided on both walls. In this case, one wobble does not include address information common to the land and the groove, but one wobble includes address information of the land or the groove. Next, an optical disk recording / reproducing apparatus for recording and / or reproducing signals on / from the magneto-optical disk 540 will be described with reference to FIG.

First, the recording operation will be described. The optical head 572 irradiates the magneto-optical disk 540 with a laser beam having a wavelength of 650 (allowable error ± 15, the same applies hereinafter) nm, and the area 554 where the groove is not formed is reproduced. The reproduced signal and the error signal in the area 554 are supplied to the reproduced signal amplifying circuit 574.
After being sent to the reproduction signal amplification circuit 574, the error signal is sent to the servo circuit 575, and the error signal is sent to the area 554.
Is sent to the synchronization signal generation circuit 577.

Referring to FIG. 5, detection of the area 554 by a photodetector in the optical head 572 will be described. The photodetector 580 has four regions A581, B582,
It is divided into C583 and D584. The photodetector 580 is arranged so that the direction indicated by the arrow 586 is the radial direction and the direction indicated by the arrow 585 is the tangerial direction.

The reflected light from the magneto-optical disk 540 is detected in areas A581, B582, C583, and D584, and DA + DD and DB + of the laser beam intensities DA, DB, DC, and DD detected in the respective areas.
DC is input to the adder 587, and the adder 587 outputs [D
After calculating [A + DD] + [DB + DC], the result is sent to the reproduction signal amplifier circuit 574 via the terminal 588 as a reproduction signal of the area 554. The reproduced signal in the area 554 has a waveform shown in FIG. This waveform (a) is detected regardless of whether the laser beam is traveling on a groove or a land.

Among the error signals, the focus error signal is [DA + DC]-[DB + DD], and the tracking error signal is [DA + DD]-[DB + DC].
Are respectively calculated by a subtractor (not shown) and sent to the reproduction signal amplifier circuit 574. The reproduction signal amplifying circuit 574 separates the reproduction signal of the area 554 from the reproduction signal, tracking error signal, and focus error signal of the area 554 sent thereto, and converts the reproduction signal of the separated area 554 into a synchronization signal generation circuit. 577, and sends a tracking error signal and a focus error signal to the servo circuit 575.

Referring to FIG. 4, synchronization signal generation circuit 577
Is the area 5 sent from the reproduction signal amplification circuit 574.
A synchronization signal is generated from the 54 reproduced signals. The generation of the synchronization signal in the synchronization signal generation circuit 577 will be described with reference to FIGS. The synchronization signal generation circuit 577 includes a comparator 601, a PLL circuit 602, and a clock generation circuit 603, and a reproduction signal of the area 554 input to the comparator 601 via the terminal 600 (shown by (a) in FIG. 6). Are compared by the comparator 601 and are converted into the signal of FIG. afterwards,
The signal (b) is input to the PLL circuit 602, and the PLL circuit 602 generates a timing signal (c) synchronized with the rise from the input signal (b). The generated timing signal (c) is input to the clock generation circuit 603, and the clock generation circuit 603 generates a synchronization signal (d) having a predetermined frequency, and controls the servo circuit 575 shown in FIG. The signal is sent to the circuit 581 and the signal format circuit 586.

In this embodiment, since 68 bytes of data are recorded between the areas 554, 554,
It is necessary to generate a synchronization signal corresponding to 544 bits. Therefore, the synchronization signal (d) in FIG. 6 is a signal in which 544 synchronizations exist between the timing signals in (c) in FIG. In the above description, the region 5 where no groove is formed
54 is detected by [DA + DD] + [DB + DC], but may be detected by [DA + DD]-[DB + DC].

After the synchronizing signal is generated, the laser beam is applied to each of the sectors 5411 and 541 of the magneto-optical disk 540.
2, 5413,..., And address information recorded by the wobble 553 at the head of each sector is detected. The address information is recorded by bi-phase modulation with the waveform denoted by reference numeral 610 in FIG. 8 as [1] and the waveform denoted by reference numeral 611 as [0]. Therefore, [101101
0] is a waveform indicated by reference numeral 612.

With reference to FIGS. 9, 10 and 11, the detection of address information recorded as wobbles will be described.
The photodetector 580 in the optical head 572 is arranged in the same manner as described with reference to FIG. 5, and its light receiving surface is divided into four regions. The address information recorded by wobble is stored in each area A
Among the intensities DA, DB, DC, and DD detected at 581, B582, C583, and D584, DA + DD and DB + DC are input to the subtractor 630, and are added to the adder 630.
Calculates [DA + DD]-[DB + DC], and sends the result to the reproduction signal amplifier circuit 574 via the terminal 631 as a reproduction signal of the wobble 612. The reproduction waveform of the wobble 612 sent to the reproduction signal amplification circuit 574 is shown in FIG.
7 (e). Reproduction signal amplification circuit 574
Sends the received reproduction signal of the wobble 612 to the address detection circuit 578 shown in FIG.

Referring to FIG. 11, address detection circuit 57
8 will be described in detail. Address detection circuit 578
Is composed of a comparator 641 and an address decoder 642. The signal (e) input via the terminal 640 is compared by the comparator 641 and converted into a binary signal shown in FIG. 9 (f). . The binarized (f) signal is input to the address decoder 642, and the address decoder 642 reads [1011010] from the binarized (f) signal to detect address information. The detected address information is sent to the control circuit 581 in FIG.

Referring to FIG. 4, servo circuit 575 rotates spindle motor 576 at a predetermined number of rotations in synchronization with the transmitted synchronization signal (the signal shown in FIG. 6D), and performs tracking. The objective lens in the optical head 572 is controlled by an error signal and a focus error signal to perform tracking servo and focus servo. The control circuit 581 controls the optical disc recording / reproducing apparatus based on the address information input from the address detection circuit 578, and sends a synchronization signal shown in FIG. 6D to the timing setting circuit 583.

The operation of the timing setting circuit 583 will be described. The timing setting circuit 583 controls the optical head 57 when recording a signal on the magneto-optical disk 540.
2, the timing of irradiating the laser beam generated by the semiconductor laser in the magneto-optical disk 540, the first timing pulse for pulsing the laser beam, and the S / N switching of the pulse magnetic field applied by the magnetic head 570 And a second timing pulse for determining the duty and the timing are generated based on the synchronization signal sent from the control circuit 581.

The timing setting circuit 583 generates first and second timing pulses based on the synchronization signal shown in FIG. 6D. The first timing pulse is supplied to the duty correction circuit 582, and the second timing pulse is supplied to the duty correction circuit 582. The signals are sent to the magnetic head drive circuit 571, respectively. Here, the first timing pulse has a phase relationship in which the laser is not turned on at the time of S / N switching of the second timing pulse. This is because when the magnetic field is switched from the S pole to the N pole, there is a certain transition time, so that even if the laser is irradiated on the magneto-optical disk at this timing, the signal cannot be accurately recorded. .

Further, the signal format circuit 586
Formats the recording data in synchronization with the synchronization signal sent from the synchronization signal generation circuit 577, and sends it to the magnetic head drive circuit 571. Also, the magnetic head drive circuit 571
Calculates the logical sum of the second timing pulse sent from the timing setting circuit 583 and the recording signal sent from the signal format circuit 586, and drives the magnetic head 570 based on the calculation result. Record the signal.

The duty correction circuit 582 adds a predetermined duty for turning on / off the laser beam to the first timing pulse sent from the timing setting circuit 583, and sends the first timing pulse to the laser drive circuit 573. Reference numeral 573 drives the semiconductor laser in the optical head 572 at a predetermined duty based on the sent first timing pulse to which the predetermined duty is added, and generates a pulsed laser beam.

Next, the reproducing operation will be described. A laser beam having a wavelength of 650 nm is irradiated on the magneto-optical disk 540 by the optical head 572, and the area 554 and the recording signal are reproduced in the same manner as when recording a signal. signal,
The wobble reproduction signal and the reproduction signal are sent to the reproduction signal amplification circuit 574, and after being amplified by the reproduction signal amplification circuit 574, the error signal is transmitted to the servo circuit 575, the reproduction signal is transmitted to the low-pass circuit 579, and the reproduction of the area 554 is performed. The signal is sent to the synchronization signal generation circuit 577, and the wobble reproduction signal is sent to the address detection circuit 578. The operations of the synchronizing signal generation circuit 577 and the address detection circuit 578 are the same as those at the time of recording, and a description thereof will be omitted. The operation of the servo circuit 575 is the same as that at the time of recording, and a description thereof will be omitted.

The control circuit 581 includes an address detection circuit 57
In addition to controlling the optical disk recording / reproducing apparatus based on the address information input from the control unit 8, the synchronization signal shown in FIG. When reproducing signals, the magneto-optical disk 54
Since no magnetic field is applied to 0, the timing setting circuit 583
In the first embodiment, a timing at which a laser beam generated by a semiconductor laser is applied to the magneto-optical disk 540 and a first timing pulse for pulsing the laser beam are generated based on a synchronization signal sent from the control circuit 581.
Duty correction circuit 5 generates the generated first timing pulse.
Send to 82.

The duty correction circuit 582 adds a predetermined duty for turning on / off the laser beam to the first timing pulse sent from the timing setting circuit 583, and sends the first timing pulse to the laser drive circuit 573. The semiconductor laser in the optical head 572 is driven at a predetermined duty based on the sent first timing pulse to which the predetermined duty is added, to generate a pulsed laser beam.

The low-pass circuit 579 removes high frequency component noise of the reproduction signal sent from the reproduction signal amplification circuit 574 and sends it to the A / D converter 580. A /
The D converter 580 performs A / D conversion in synchronization with the synchronization signal sent from the control circuit 581, and sends the A / D converted to the high-pass filter 584. The high-pass filter 584 removes low-frequency noise caused by birefringence of the disc and the like, and converts the reproduced signal into a PRML (Partial Response) signal.
Maximum Likely circuit) circuit 58
Send to 5. The PRML circuit 585 performs three-valued determination on the reproduced signal, and demodulates the reproduced signal with less errors.

In this embodiment, a region where no groove is formed periodically is provided in the groove of the magneto-optical disk in order to generate a synchronization signal. However, the present invention is not limited to this. Any optical disk can be used as long as the optical disk has the appearance of the optical disk.

[0034]

As described in detail above, according to the present invention,
Since wobbles are not formed on the walls on both sides of the groove in the area where the signal is recorded or reproduced, the polarization direction of the light reflected by the groove is affected by the wobble, and there is a leak that the effect appears in the reproduction characteristics. And good reproduction characteristics.

Further, according to the present invention, since both land and groove addresses can be used with one piece of address information, it is sufficient to record one address with wobbles, and the efficiency of format can be further improved. Furthermore, since the area where the groove for generating the synchronization signal is not provided is provided every 68 bytes, the synchronization signal can be reliably generated, and the characteristics in recording or reproducing the signal can be improved. Can be.

[Brief description of the drawings]

FIG. 1 is a plan view of a magneto-optical disk according to the present invention.

FIG. 2 is a perspective view illustrating the structure of a land and a groove of a magneto-optical disk according to the present invention.

FIG. 3 is a plan view illustrating the structure of lands and grooves of a magneto-optical disk according to the present invention.

FIG. 4 shows a recording and / or a magneto-optical disk according to the present invention.
FIG. 2 is a block diagram of an optical disk recording / reproducing apparatus for performing and reproducing.

FIG. 5 is a diagram illustrating detection of an area where no groove is provided.

FIG. 6 is a diagram illustrating a change in a signal for generating a synchronization signal.

FIG. 7 is a block diagram of a synchronization signal generation circuit according to the present invention.

FIG. 8 is a diagram illustrating a recording method of address information according to the present invention.

FIG. 9 is a diagram showing signal changes for explaining reproduction of address information in the present invention.

FIG. 10 is a diagram illustrating detection of address information according to the present invention.

FIG. 11 is a block diagram of an address detection circuit according to the present invention.

FIG. 12 is a diagram showing a tracking control method and an address detection method for recording and reproducing lands and grooves using three beams according to a conventional method.

[Explanation of symbols]

 540 Magneto-optical disk 551 Groove 553 Wobble 554 Area where no groove is provided 555 Groove 571 Magnetic head drive circuit 572 Optical head 573 Laser drive circuit 574 Reproduction signal amplification circuit 575 Servo circuit 577 Synchronization signal generation circuit 578 Address detection circuit 579 Low pass circuit 580 A / D converter 581 Control circuit 582 Duty correction circuit 583 Timing setting circuit 584 High pass filter 585 PRML circuit 586 Signal format circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 11/105 553 G11B 11/105 553D 563 563P 586 586W (31) Priority claim number Japanese Patent Application No. Hei 8-301426 (32) Priority date November 13, 1996 (November 13, 1996) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-6988 (32) Priority date 1997 January 17, 1997 (Jan. 17, 1997) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-12790 (32) Priority date January 27, 1997 (1997) 2.1.27) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-25655 (32) Priority date February 7, 1997 (1997.2.7) (33) ) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-56681 (32) Priority date March 1997 (11) March 11, 1997 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-95700 (32) Priority date April 14, 1997 (April 1997) 14) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-106368 (32) Priority date April 23, 1997 (April 23, 1997) (33) Priority Claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 9-109436 (32) Priority date April 25, 1997 (April 25, 1997) (33) Priority claiming country Japan (JP) ( 31) Priority claim number Japanese Patent Application No. 9-140087 (32) Priority date May 29, 1997 (May 29, 1997) (33) Priority claim country Japan (JP) (72) Inventor Noboru Mamiya Osaka 2-5-5 Keihanhondori, Moriguchi-shi, Sanyo Electric Co., Ltd. (72) Inventor Koji Uchihara 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Satoshi Sumi 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Kenji Nakao Kyo, Moriguchi-shi, Osaka 2-5-5 Hondori Sanyo Electric Co., Ltd. (72) Inventor Toshiaki Hioki 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hisashi Matsuyama Moriguchi, Osaka 2-5-5 Keihan Hondori, Sanyo Electric Co., Ltd. (72) Inventor Yoshihiro Hori 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (7)

[Claims] 1. An optical disk capable of recording and reproducing data on a land and a groove, wherein a wobble including address information for the land and the groove is provided on one of the walls of the groove, and an area other than a region where the wobble including the address information is provided is provided. An optical disc characterized in that, in the area, an area where no groove is provided periodically exists. 2. The optical disk according to claim 1, wherein the address information is recorded by a bi-phase modulation method. 3. The optical disk according to claim 1, wherein the address information is information common to a groove and a land. 4. A groove comprising a land and a groove, a wobble including address information for the land and the groove is provided on one of the walls of the groove, and a groove other than a region where the wobble including the address information is provided. An optical disc recording / reproducing apparatus for recording / reproducing on / from an optical disc in which an area not provided with a magnetic field is provided; a magnetic head for applying a magnetic field to the optical disc; an optical unit for irradiating the optical disc with a laser beam; And a control circuit for controlling the optical unit and the magnetic head based on the synchronization signal generated by the synchronization signal generation circuit. An optical disk recording / reproducing apparatus characterized by the above-mentioned. 5. The optical disk recording / reproducing apparatus according to claim 4, wherein the synchronization signal generation circuit generates a synchronization signal based on a reproduction signal from an area other than an area including the address information. 6. The synchronizing signal generation circuit, a comparator for binarizing a reproduction signal reproduced by the optical means, a PLL circuit for generating a timing pulse from the signal binarized by the comparator, and the PLL. 6. The optical disk recording / reproducing apparatus according to claim 5, further comprising: a clock generation circuit that generates a synchronization signal including a predetermined clock based on the timing pulse generated by the circuit. 7. A photodetector in said optical means has a light receiving surface comprising a first area, a second area, a third area, and a fourth area, and wherein said first, second, A reproduction signal is obtained from an area other than an area including the address information by calculating a sum of reflected light intensities of the laser beams detected on the optical disk in third and fourth areas. 7. The optical disk recording / reproducing apparatus according to 6.