JP2796302B2 - Optical disk recording or reproducing method, optical disk apparatus, and information arranging method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording or reproducing method, an optical disk device, and an information arranging method.

2. Description of the Related Art Conventionally, as a method of generating a clock signal used for recording and reproducing data, a method of generating a clock signal using a synchronization area in which a synchronization flag is written as described in JP-A-58-185046 is known. Are known.

In JP-A-63-53760, a servo signal is generated using a servo signal area in which a servo signal is recorded.

[Problem to be Solved by the Invention] In the conventional technology, when a clock is generated using this synchronous area, it is necessary to increase the number of synchronous areas in order to increase the accuracy of the clock. However, in that case, there is a problem that data efficiency is reduced.

In addition, when a track identification pattern for access is added, if the access is to be performed at high speed, the number of track identification patterns increases, and the data efficiency as a whole deteriorates.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a synchronous area and a servo area having a larger number of servo areas than the synchronous area. The mode is switched between a coarse synchronization mode in which a clock is generated using a synchronization area and a fine synchronization mode in which a clock is generated using a servo area when the clock is settled.

In addition, when track identification information is added as another invention, the phase of a synchronization area or a servo area is shifted for each track, and the number of steps is incorporated in the synchronization area as data, as a format of an optical disc in order to increase data efficiency. When generating a clock, a selector circuit for selecting a clock pulse corresponding to the number of steps is used.

[Operation] In the coarse synchronization mode, by using the signal in the synchronization area,
Generates a reliable clock and separates the servo area from the data area. Thus, the servo area can be configured in a simpler form, and the data efficiency can be improved.
In the fine synchronization mode, there are many servo areas,
You can make an accurate clock. At the start of the operation or when there is a rotation fluctuation due to a disturbance, switching to the coarse synchronization mode enables a clock to be reliably generated even if there is a disturbance.

Even when a track identification pattern is added, data efficiency can be increased by inserting position information into the synchronization area and shifting the phase for each track.

Example An example of the present invention will be described below with reference to FIG.
About JAPANESE JAOURNA
L OF APPLIED PHYSICS Vol.26 (1987) Suppl.26-4, pp1
49-154, and the operating principle of the recording / reproducing optical system is described in pp. 117-120 of the same book. Therefore, the description is omitted here, and the system configuration as an optical disk device is described. In FIG. 1, a disk 1 is driven by a rotating spindle 2, and a magnetic coil 3 is set on the disk surface and floats from the disk surface with a gap of several microns. An optical head 4 is placed facing the magnetic coil, and a light spot from the optical head is positioned in a magnetic field region generated by the magnetic coil 3. The signal detected by the optical head 4 enters an arithmetic processing circuit 10, where it is divided into a magneto-optical signal and a signal from a pre-pit. The magneto-optical signal enters a data demodulation circuit 11, and a reproduction clock RCK and a gate signal indicating the location of the data. The data is demodulated by the RDT and sent to the data controller 15.

The pre-pit signal from the arithmetic processing circuit 10 first enters the clock generation circuit 12, and generates clocks RCK and WCK necessary for data recording / reproduction and tracking. Further, the pre-pit signal enters the track shift detecting circuit 14 and generates a track shift signal TE using a control signal from the timing generating circuit 13. Further, the pre-pit signal enters a timing generation circuit 13 and uses a clock signal from the clock generation circuit 12 to control a signal for detecting a track deviation, a control signal for detecting position information for access, and a recording / reproduction signal. A signal for controlling data is generated, and a track shift detecting circuit 14 and an access controller 1 are respectively provided.
6. Send to data controller 15.

A signal from the pre-pit is input to the access controller, and information indicating the position of the light spot is detected using a signal from the timing generation circuit 13. Further, a signal from the track shift detecting circuit 14 is input to detect minute track information. Command information FA and CA for controlling the two actuators is transmitted based on these signals and the target track number commanded by the host CPU 17. The reproduction data processed by the data controller is sent to the host CPU 17. On the other hand, data to be recorded is sent from the upper CPU 17 to the data controller 15, added with control data such as an ECC (error correction code) and subjected to processing such as interleaving, and then sent to the data modulation circuit 20. In this circuit, data pulses to be actually recorded on the disk surface are created using signals from the clock creation circuit 12 and the timing generation circuit 13. In accordance with this signal, the coil driver 7 is driven to modulate the magnetic field. The power of the spot on the disk surface is controlled by the laser drive circuit 6, and this timing is synchronized with a signal WRC indicating the recording / reproducing state output from the host CPU. A part of the detection signal from the optical disk is input to the focus error detection circuit 19 to create a control signal AF of the automatic focus servometer, input this to the light spot control circuit 9 and perform phase compensation. The voice coil lens 21 is driven to perform focus servo. The track deviation signal TE is input to the light spot control circuit 9, and after processing such as phase compensation, a signal for controlling the fine actuator and the coarse actuator is created.

A signal to the coarse actuator drives the coarse actuator 5 via the coarse drive circuit 8 to move the entire head in the disk radial direction. The signal FA from the access controller and the signal FA are input to the light spot control circuit 9 to control the fine actuator, thereby enabling a minute and high-speed light spot control at the time of access. In addition, the signal
The CA is input to the course drive circuit 8 and controls macro movement of the entire optical head at the time of access. A signal WRC representing recording / reproduction is input to a clock generation circuit 12 and a timing generation circuit 13, and controls respective output signals according to a recording / reproduction state. The above is the overall configuration of the optical disk drive of the present invention.

Next, the pre-pit shape will be described with reference to FIG. A pit pattern is provided on one track on the disk surface by repeating it for each sector of the data division unit.
This sector is provided with an ID section that has address information and other control information at the beginning, and further, for the center of the track,
Pre-pits that are slightly meandered on the left and right are arranged. Data is recorded during this pre-pit. In the conventional method, as shown in FIG. 4, a pit pulse indicating a pit position is created from the pre-pit, and a clock signal for recording and reproducing data and a track shift signal are simultaneously detected from the pit pulse.

FIG. 3 shows a specific waveform of the track shift signal.
As the meandering state of the pre-pits, there are an in-phase pit and a phase inversion pit as shown in FIG. For these pit patterns, a track shift signal when the servo operation is OFF and a following state when the servo operation is ON are shown.

For the data, a clock signal synchronized with the pit pulse shown in FIG. 4 is created, the recording data is modulated using this clock, and is recorded in the data area between the pre-pits. In the magnetic field modulation overwrite method, the formed magnetic domains have a strip shape as shown in FIG. Also in the case of reading this, the clock created from the pre-bit has conventionally been used. This has the following problems. That is, in FIG. 5, due to the irradiation of the data pulse, the temperature distribution on the disk surface matches the intensity distribution of the light spot, and becomes a distribution trailing by Δ1 behind the light spot. According to the principle of magnetic field modulation overwriting, a point on the disk surface where the temperature is lower than the Curie temperature is recorded according to the magnetization direction of the external magnetic field. Therefore, Δ2 from the center of the distribution
Assuming that the temperature becomes equal to or lower than the Curie point at the deviation, the deviation Δ3 between the edge of the data pulse and the edge of the recording domain is the sum of Δ1 and Δ2.

From the above, in the magnetic field modulation overwrite method, the recording pulse and the domain deviate in principle. However, it is considered that this shift amount depends on the irradiation power, the linear velocity, the disk sensitivity, or the like, or is almost constant in the same sector, and does not change in each domain. For this reason, a self-clocking method of generating a clock from data is adopted as a reproduction clock generation method.

There is another problem. When the magneto-optical signal and the signal from the pre-pit are detected by the difference and the sum of the two polarization components as described later, the intensity ratio of the two signals is about 1:50 to 100, and the pre-pit signal leaks into the magneto-optical signal. Come in. For example, reproduction spot diameter 1.5μmφ, pre-pit diameter
When the diameter is 0.6 μm φ, the pre-pit signal becomes equal to the magneto-optical signal at a distance of about 1.3 μm, and in consideration of a signal detection margin, the data must be separated by about 2 to 2.5 μm from the center of the pit. Therefore, an empty area of about 4 to 5 μm is provided around the pre-pit.

Further, when the pits are differentiated in order to detect the position of the pre-pit, an erroneous signal is generated due to noise, a defect, or the like on the disk, and an erroneous signal is generated from the pre-pit position. In addition, it is necessary to know the phase of meandering in order to detect a track shift signal. For this purpose, a synchronization mark is formed on the disk in the form of a pre-pit in advance, and the synchronization mark is detected to determine the meandering phase and to identify the position of the pre-pit.

FIG. 6 shows a track format considering the above. One track includes N sectors, one sector includes M blocks, and one block includes L prepit pair areas. One pre-pit pair area includes pre-pits, an empty area sandwiching the pre-pits, and a data area. Taking a 3.5 ″ optical disk as an example, the number of data bytes in one track is unformatted to 18 KB, the number of sectors N is about 20 to 24, M is about 20 to 40, and L is about 8 to 16. Also, a tracking servo clock is created. The number of pre-pits and the number of tracks per track are about 6000-3000.

As a modulation method, a fixed length code is preferable because data is held at a fixed length. There are 8/9 conversion, 4/5 conversion, a certain 2-7 modulation method, etc. that can be self-clocked by such a modulation method. However, a variable length code is also applicable in consideration of recording density efficiency.

Among them, 2-7 modulation and 1-7 modulation are excellent methods,
2-7 modulation from the viewpoint of density, 1 from the detection margin
-7 modulation has advantages. In a recording / reproducing system such as a magneto-optical disk having a strict S / N ratio and a small amplitude deterioration at a data frequency to be used, 1-7 modulation having a sufficient detection margin is advantageous.

As a recording method, there is a pit position recording as shown in FIG. 6 or an edge recording as shown in FIG. The pit position recording does not require special consideration for the modulation method, but the recording density is lower than that of the pit edge recording. In pit edge recording, since the data has a fixed length, it is possible to control that the start point and the end point of the recorded data must match one of the recording levels. To avoid this, add an additional bit according to the data before modulation so that the end point of the data after modulation always matches one of the recording levels, or add an additional bit to the data after modulation and change the recording level. We have to do the matching.

7 and 8, a method of processing a detection signal using this format will be described. When the light spot 70 on the disk 1 passes through the tracks 71 and 72, the reflected light is transmitted to the voice coil lens 21 and the galvanomirror deflector.
After passing through 34, a part of the light is reflected by the beam splitter 30 and further separated by the beam splitter 33, and one part enters the defocus detection system 19. The other is 1/2 board 3
The polarization component is divided by the polarization beam splitter 36 following 5, and the detectors 38,
Focused on 40. By adding and subtracting the signals from the detectors 38 and 40, respectively, the pre-pits and the reflected light from the disk can be detected from the sum signal, and only the magneto-optical signal component can be obtained from the difference signal. The sum signal 73 changes corresponding to the pre-pits as shown in FIG. 8 by passing through the pre-pits 74 to 83. A low-pass filter 42 for removing this signal 73 through an amplifier 41 to remove high-frequency sounds.
, And the output is differentiated by a differentiating circuit 43. The differentiated signal 88 is obtained at a certain threshold by the comparator 44 to obtain the comparator 1 and the signal 89, and the monomultivibrator 45 expands the pulse width to obtain a signal 90, which is a signal 91 at the zero crossing point of the differentiated signal 88. Is obtained by the cross point detection circuit 46, and a logical AND with the signal 90 is obtained, so that a pit signal 92 indicating only the pre-pit portion is obtained.
This signal 92 is input to the shift register 48,
47, the pit signal is time-shifted and
A synchronization mark composed of pre-pits 86 and 87 is generated from the time interval between 86, 87 and 77 and 82, and a synchronization timing 93 is generated from the delay time of the register 48. The pit signal 92 is input to a PLL (phase locked loop) 49 for generating a clock, and a clock WCK synchronized with the pit signal is generated.
The signal WCK is input to a frequency dividing circuit 50 composed of a counter, and an estimated pulse 94 is generated at a pre-pit cycle in accordance with the timing at which the pre-pit exists. The start timing of the counter 50 is determined by the above-described synchronization timing 93. The signal 94 is input to the flip-flop 53, and a signal having a period twice as long as the period of the pre-pit is created. When the signal 94 is ANDed, the signals φ1 and φ2 are obtained. Timing information corresponding to the position of the pit. Further, the clock signal WCK is input to the frequency dividing circuit 51 composed of a counter, and the start timing of the counter is set by the signal 94 so that a pulse is generated just in the middle of the pre-pit. The signal is φ3.

The outputs of the low-pass filter 42 are input to sample and hold circuits 57 and 58, respectively, and sample and hold are performed by signals φ1 and φ2, respectively. Each output is output to a differential amplifier 59
And take the difference. Although this output can be used as a track shift signal, the signal passed through the inverting circuit 60 and the signal as it is are input to the respective inputs of the analog switch 61, and this signal is inverted by the signal φ3 and the inverter 62. , The sampling frequency for detecting the track deviation can be effectively doubled.

As the synchronization pattern, a specific pattern having a time arrangement not in the meandering pre-pit row such as the pre-pits 86 and 87 may be used. However, as shown in FIG. But it is good. Also, the slots can be arranged between the tracks. Similarly, pits 84, 85, 86, 8
7 patterns can be inserted between tracks. In this way, the synchronization mark can be detected even if the light spot is between the tracks. Further, considering the application of the optical disk in the future, the write-once type disk which has been used so far can be reproduced by this apparatus. At this time, the data is detected from the private signal, and becomes a signal at the same level as the track shift signal and the synchronization mark. In order for the synchronization mark to be distinguished, a pit pattern not present in the recording data may be provided.

The data tone will be described. The difference signal is converted into a digital signal by a binarization circuit 54 and input to a phase comparator 55. W of the clock from PLL49 is input to the other input.
A signal subjected to the CK phase shift is input, and the phase shift circuit 56 is controlled by the output of the phase comparator 55. In this way, even if there is a domain shift at the time of recording, it is possible to move only the phase and synchronize with the recording data. The reproduction clock RCK is input to the demodulation circuit 11, and the data is demodulated. With this configuration, since the prepit-synchronized clock WCK is used for recording, recording can be performed without being affected by disc eccentricity and rotation fluctuation.

On the other hand, at the time of reproduction, a clock having the same frequency as the recorded data is detected without being affected by disk eccentricity and rotation fluctuation in synchronization with the prepit. Here, if only the phase shift is detected from the data and the phase is adjusted, a clock RCK for reproduction synchronized with the data can be obtained.

Another embodiment for generating a reproduction clock will be described with reference to FIG. The signal φ4 is input to the F / V converter 101, the frequency is converted to a voltage, and then compared with the reference speed voltage by the differential amplifier 102, and the difference is compared with the phase compensation circuit 103.
Through the adder 104. To the other end of the adder 104, a phase shift between the output of the voltage controlled oscillator 105 and the binarized signal of the magneto-optical signal is detected by the phase comparator 107, and the result of passing this output through the phase compensation circuit 106 is input. . In this way, a two-input, one-output controller is obtained. This loop is composed of an F / V system and a PLL phase control system, and its loop characteristics are desired to have a configuration as shown in FIG. In the F / V system, the crossover frequency fc2 is selected to be about 2 to 5 kHz in order to have inertia.
The phase control system has a frequency of several hundred kHz in normal self-clocking, but if the band is expanded in this way, the effect of noise will increase, so fc1 should be about 1 digit times fc2, 20 to 50 kHz. . In this way, the reproduced clock does not run away due to a defect or the like, and the jitter due to noise is reduced as compared with a normal self-clock. The gain is increased and the tracking characteristics are improved.

FIG. 11 shows an embodiment of access to the optical disk of the present invention.

FIG. 12 shows an embodiment of the spot position signal generator of the present invention. According to a known method, the detected optical signal is binarized and input to the synchronization detector 48 and the gate circuit 100.
The synchronization detector detects a synchronization area using a known method such as pattern matching, and generates a synchronization pulse 93. The phase difference between the synchronization pulse 93 and the clock pulse divided by the counter circuit 50 is detected by the first phase comparator A. When the phase difference is large at the start of operation or due to rotation fluctuation due to disturbance, the switch is switched to enter the coarse synchronization mode. In the coarse synchronization mode, the phase control loop (PLL) is closed for the synchronization pulse. The output of phase comparator A is a low-pass filter (LP
F) After passing through 102, a clock is generated by a voltage controlled oscillator (VCO) 103, and the frequency is divided by a counter circuit 50.

The determination circuit 104 detects that the coarse synchronization mode has been pulled in, and switches the switch 101 to enter the fine synchronization mode. In the fine synchronization mode, PLL is performed on the servo pit. The gate circuit 100 receives the gate signal 100 at a timing at which a servo pit can be detected from the counter circuit 50, and generates a servo pulse, which is a servo pit signal, from among the data signals.
Take out 91 '. In the phase comparison circuit B, the servo pulse 9
Each time 1 'is input, the phase is compared with the clock 105.

Even in the fine synchronization mode, the output of the phase comparator A is monitored. If the PLL greatly fluctuates due to a defect on the disk or the like, the absolute value of the output of the phase comparator A increases. This is detected at a predetermined slice level, and the mode shifts to the coarse synchronization mode.

The number of servo areas and the number of synchronization areas per track determines the performance of the PLL in the fine synchronization mode and the coarse synchronization mode. In the synchronization area, a special pattern having a length of about 1 to 5 bytes is recorded, and several hundreds are arranged per track. The servo area has a length of 0.5 to 1 byte and has one or two servo pits.
About 00 to 6000 pieces are arranged.

PLL servo band is 1/1 frequency of input pulse to be synchronized
It can be increased to about 0. Therefore, in the coarse synchronization mode, by using the signal of the synchronization area, a reliable clock is generated and the servo area is separated from the data area. This allows the servo area to be configured in a simpler form,
Data efficiency can be increased. If a part of the synchronization pattern is replaced with a servo pit, the synchronization area can be shortened. Since the servo pits and data pits are separated by the gate signal, the clock phase error and frequency error in the coarse synchronization mode are within the allowable range, and the gate does not shift even in the transient state when switching to the fine synchronization mode. is necessary. According to this condition, the number of synchronization areas is determined. FIG. 13 shows the signal waveform of each part. The phase comparator A shows a characteristic as shown in FIG. In this case, a sawtooth waveform or a sine wave characteristic may be used. Also, a phase frequency comparator can be used. The servo pulse 91 'has already been detected in the coarse synchronization state. In the state where tracking is not performed, the detection position of the servo pulse is shifted for each step as shown by the dotted line in the figure,
When the phase comparator B has a sawtooth waveform characteristic as shown in the figure, the PLL can operate normally. Such a phase comparator is used in, for example, a clock demodulation circuit for a 2-7 modulated signal, and is not specifically illustrated.

The two steps to which the track on which the light spot scans belong to can be measured continuously only by the phase of the servo pits, once knowing from the synchronization pattern and the address data.
The number of steps is required to be the same as the number of tracks that the light spot can traverse during the period of the servo pit. This number is determined based on the examination of the access capability as described later. Since the number of servo pits is large, the clock generated in the fine synchronization mode is accurate and can be used as a reference clock for recording and reproducing data.

FIG. 14 shows access to the optical disk of the present invention.
An example will be described. The servo area is shorter and the synchronization area and the data area are also out of phase for each track. An embodiment of the spot position signal generator in this case is
Figure 15 shows. In the synchronization area, the number of steps is recorded as data. In the synchronization recognition circuit 48, the number of steps is detected simultaneously with discrimination from the data pattern. The corresponding clock pulse P is selected by the selector circuit. Are compared. In this case, the synchronization area becomes longer but the servo area becomes shorter, so that the overall efficiency can be improved.

JP-A-62-143232 describes a method of adding a track identification pattern. In this case, the clock synchronization information and the track identification information are obtained from different areas. That is, as shown in FIG. 16, a PLL is constituted by the detection signal of the synchronization pattern, and the track identification pattern is decoded based on the PLL. However, in this configuration, if the clock used for recording / reproduction is obtained from the PLL, the number of synchronization patterns increases, and if the access is further performed at high speed, the number of track identification patterns increases, and the overall data efficiency deteriorates. There were drawbacks. The present invention solves this problem by the configuration described above.

In the embodiment of the present invention described above, preferred examples of the number of bytes in the servo area and the data area and the number of access steps are summarized as follows.

In the conventional pre-pit pattern of Japanese Patent Application Laid-Open No. 62-143232, one access information 1 cannot be obtained for the first time with a pair of pre-pits. Can't fit.

Further, as an access pattern, there is a pattern as shown in FIG. In this case, the track intermediate position can be obtained during the seek even during the high-speed seek, so that the resolution can be improved. Since the speed of the pull-in operation can be reduced by about 1/2, the settling time is short and the pull-in can be performed stably.

[Effects of the Invention] According to the present invention, a tracking signal and clock information can be detected from a servo area with high reliability and data efficiency is high.

Further, according to another invention, it is possible to detect a light spot position information for access by adding a track identification pattern, to detect a tracking signal and clock information from a servo area with high reliability, and to improve data efficiency as compared with the related art. Can be raised.

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical disk apparatus of the present invention, FIG. 2 is a basic block diagram of a track format, FIG. 3 is an explanatory diagram of a detection signal from prepits, FIG. FIG. 6 is an explanatory diagram of a recording timing shift, FIG. 6 is a format explanatory diagram of the present invention, FIG. 7 is a configuration diagram of a detection request of the present invention, FIG. 8 is a time chart of a detection system, and FIG. FIG. 10 is a block diagram of generation of a reproduction clock, and FIG. 11 is an access pattern 1 of the present invention.
FIG. 12 is a block diagram of a clock system using the access pattern of FIG. 11, FIG. 13 is a signal waveform diagram thereof, and FIG. 14 is an explanatory view of another embodiment of the access pattern of the present invention. FIG. 15 is a block diagram of a clock system using the access pattern of FIG. 14, FIG. 16 is a block diagram of a clock system using a conventional access pattern, and FIG. 17 is another embodiment of the access pattern of the present invention. It is explanatory drawing of an example.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshito Tsunoda 1-280 Higashi Koikebo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory of Hitachi, Ltd. (56) References JP-A-58-185046 (JP, A) JP-A-58 -171728 (JP, A) JP-A-63-53760 (JP, A) JP-A-1-229428 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 7/09 G11B 11/10 G11B 21/00

Claims (21)

(57) [Claims] 1. A recording or reproducing method for an optical disk having a plurality of sectors and having a synchronization area and a servo area having a greater number of servo areas in each of the plurality of sectors, comprising: Generating a clock based on the signal from the servo area when a phase difference between the signal from the synchronous area and the clock based on the synchronous area becomes smaller than a predetermined level; Wherein the clock based on the signal from the servo area is used as a reference clock for recording and reproducing data. 2. The optical disk recording or reproducing method according to claim 1, wherein a signal from the synchronous area is compared with a clock based on the servo area, and a signal from the synchronous area and a clock based on the servo area are compared. A recording / reproducing method for an optical disc, characterized in that when the phase difference between the two is greater than a predetermined level, switching is performed so as to generate a clock based on a signal from the synchronization area. 3. An optical disk recording or reproducing method according to claim 1, wherein said clock is generated by a phase control loop. 4. A plurality of tracks each having a plurality of sectors, each of the plurality of sectors having a synchronization area having position information in each sector, and a servo area having a larger number than the synchronization area. A recording / reproducing method for an optical disc in which the phase of the synchronous area and the servo area of each track is shifted from the phase of the synchronous area and the servo area in a sector of an adjacent track in accordance with the position information. Generating a clock based on a signal from the synchronization area; detecting the position information from the synchronization area; selecting a clock pulse corresponding to the phase shift from the clock based on the position information; The signal from the synchronous area and the clock pulse are compared by comparing the signal from the synchronous area with the clock pulse. A recording or reproducing method for an optical disk, characterized in that the phase difference is controlled to be small. 5. The recording or reproducing method for an optical disk according to claim 4, wherein when the phase difference between the signal from the synchronization area and the clock pulse becomes smaller than a predetermined level, the signal from the servo area is read out. A recording or reproducing method for an optical disk, characterized in that switching is performed so as to generate a clock based on a signal. 6. The optical disk recording or reproducing method according to claim 5, wherein a clock based on a signal from said servo area is generated by a phase control loop. 7. The recording or reproducing method for an optical disk according to claim 5, wherein a clock pulse corresponding to the phase shift based on the position information is generated by a clock pulse based on a signal from the servo area. The signal from the synchronous area is compared with the clock pulse, and when the phase difference between the signal from the synchronous area and the clock pulse becomes larger than a predetermined level, the signal from the synchronous area is A recording or reproducing method for an optical disk, characterized in that switching is performed so as to generate a clock based on a signal. 8. The optical disk recording or reproducing method according to claim 5, wherein a clock based on a signal from the servo area is used as a reference clock for recording and reproducing data. Recording or playback method. 9. An optical disk apparatus using an optical disk having a plurality of sectors and having a synchronization area and a servo area having a larger number of servo areas in each of the plurality of sectors, a signal from the synchronization area. A coarse synchronization mode circuit that generates a clock based on a signal from the servo area; a fine synchronization mode circuit that generates a clock based on a signal from the servo area; and the synchronization with the clock from the coarse synchronization mode circuit or the fine synchronization mode circuit. A determination circuit for determining a phase difference from a signal from an area; and a circuit for generating a clock when the phase difference is smaller than a predetermined level based on a result of the determination circuit, is switched to a fine synchronization mode circuit. And a switching circuit, wherein a clock by the fine synchronization mode circuit is used as a reference clock for recording and reproducing data. Optical disc apparatus characterized by. 10. The optical disk device according to claim 9, wherein said switching circuit includes a circuit for generating a clock and a coarse synchronous mode circuit when said phase difference is larger than a predetermined level. An optical disk device characterized by switching to a fine synchronization mode circuit when the size is smaller. 11. The optical disk device according to claim 9, wherein the clock is generated by a phase control loop. 12. A plurality of sectors in each of a plurality of tracks, a synchronous area having position information in each sector of the plurality of sectors, and a servo area having a larger number of servo areas than the synchronous area. An optical disc apparatus using an optical disc in which the phase of the synchronization area and the servo area of each track is shifted from the phase of the synchronization area and the servo area in a sector of an adjacent track in accordance with the position information, A clock generation circuit that generates a clock based on a signal from the synchronization area or a signal from the servo area; a detection circuit that detects the position information from the synchronization area; and a phase shift based on the position information. An optical disc device having a selector circuit for selecting a corresponding clock pulse from the clocks. 13. The optical disk device according to claim 12, wherein a judgment circuit for judging a phase difference between a signal from the synchronization area and the clock pulse, and a clock generation circuit based on a result of the judgment circuit, An optical disc device having a switching circuit for switching between a coarse synchronization mode for generating a clock based on a signal from a synchronization area and a fine synchronization mode for generating a clock based on a signal from the servo area. 14. The optical disk device according to claim 13, wherein said switching circuit is set to a coarse synchronization mode when said phase difference is larger than a predetermined level, and to a fine synchronization mode when said phase difference is smaller than a predetermined level. An optical disk device characterized by switching to a mode. 15. The optical disk device according to claim 12, wherein the clock is generated by a phase control loop. 16. The optical disk device according to claim 12, wherein a clock in the fine synchronization mode is used as a reference clock for recording and reproducing data. A plurality of sectors are provided in each of the plurality of tracks, a synchronization area and a servo area having a greater number of servo areas than the synchronization area are provided in each of the plurality of sectors, and a sector of an adjacent track is provided. Are arranged such that the phases of the synchronous area and the servo area of each track are shifted with respect to the phase of the synchronous area and the servo area, and position information corresponding to the phase shift is set in the synchronous area. An information arrangement method characterized in that: 18. The information arranging method according to claim 17, wherein a mark deviated left and right with respect to the center of the track is provided in each of the servo areas. 19. The information arrangement method according to claim 17, wherein a pair of marks deviated left and right with respect to the center of the track are provided in each of the servo areas. Placement method. 20. The information arrangement method according to claim 17, wherein one of said servo areas is arranged so as to be incorporated in a part of said synchronous area. 21. The information arrangement method according to claim 17, wherein a mark used for tracking is provided in the servo area, and a specific pattern or a time pattern in the synchronous area that is not in the servo area is provided. An information arrangement method characterized by providing a slot pattern.