JP2953711B2 - Optical disc recording method and reproducing method thereof - Google Patents

Description

The present invention relates to a recording method for an optical disk and a reproducing method therefor, and relates to a signal recorded in advance on a recording track by a displacement in the width direction of the recording track. The present invention relates to a method of recording information on an optical disk so as not to affect the information, and to a method of reproducing information recorded on the optical disk.

B. Summary of the Invention The present invention uses an optical disk in which a recording track is pre-recorded by being displaced in the width direction of the recording track based on first information including a frame synchronization signal. When recording the second information including the phase pull-in signal of the signal processing clock along the signal processing, the change point due to the displacement of the recording track in the width direction is shifted from the change point of the second information. By doing so, the change point of the second information recorded along the recording track and the change point of the first information overlap, thereby causing jitter in the synchronization signal and deteriorating the pull-in accuracy of the phase pull-in of the PLL circuit. To prevent that.

C. Prior Art In an optical recording medium, for example, a magneto-optical disk, a guide groove for tracking is previously formed in a spiral or concentric shape on the disk, and the guide groove (so-called pre-groove) formed in advance is used. Alternatively, there is known a structure in which a land portion between grooves is used as a recording track, and data is recorded and reproduced on the recording track using the magneto-optical effect along the track direction. This means that information (data) is recorded optically, while optically detecting the guide groove and applying tracking servo.
It is for regenerating.

In this case, control information such as a synchronization signal and an address and data are alternately recorded on a recording track,
It is known to perform data management or the like based on the control information, and the control information records and reproduces data in block units or sector units.

Japanese Patent Application Laid-Open No. 63-87682 discloses a technique in which a wobbling track for detecting a tracking error is FM-modulated with a time code and recorded and formed. In this technology, for example, a carrier signal of a 20.05 kHz sine wave is FM-modulated based on a time code signal of a frequency sufficiently lower than the carrier to form a wobbling track, and a tracking error signal is obtained during reproduction. At the same time, the time code is demodulated to obtain a time code as position information. However, in this prior art, clocking of the recording signal on the track cannot be performed depending on the wobbling signal of the track, and the time information of the wobbling signal includes one set of information in one block. It is difficult to perform accurate positioning because the extraction accuracy is low and decoding cannot be performed unless one block is read.

In order to reproduce main information, for example, a magneto-optical signal, recorded along the track direction on the recording track, a long so-called preamble area for reproducing a clock (performing clocking) is provided at the head of the main information. There is known a method for extracting a clock for reproducing a magneto-optical signal from a signal written in the preamble area.

D. Problems to be Solved by the Invention In order to solve the above problems, the present inventors displace the recording track in the track width direction and record and form control information such as a frame synchronization signal and an address in advance, and perform this control. A method of reproducing information and using it as a frame synchronization signal or address information in recording and reproducing a main signal (main information) has already been proposed. Further, the present inventors use the frame synchronization signal recorded by the track width direction displacement as a frequency pull-in signal of a PLL, perform a phase pull-in of the PLL by a signal recorded on a recording track, and It also proposes ways to shorten it.

By the way, a signal recorded by displacing a recording track in the track width direction has an effect on a main signal recorded on the recording track, and in particular, in the above-described PLL phase pull-in, recording is performed by displacement in the track width direction. If the change point of the reproduced signal and the change point of the signal recorded on the track overlap each other, they interfere with each other, causing adverse effects such as generation of jitter in the reproduced clock.

The present invention has been made in view of such circumstances, and prevents a signal recorded due to a displacement in a track width direction from having an adverse effect on a main signal recorded on a track. A method of recording an optical disk, in which a main signal recorded on a track can be clocked in a short time with high accuracy (accurately) by a signal recorded in advance by a displacement and a signal recorded on a track. The purpose is to provide a reproduction method.

E. Means for Solving the Problems In order to achieve the above-described object, the recording method of the optical disk according to the present invention is configured such that the recording track has a width direction of the recording track based on the first information including the frame synchronization signal. Using an optical disk that is displaced in
When recording second information including a phase pull-in signal of a signal processing clock on the optical disk along the recording track, a change point due to a displacement of the recording track in a width direction and a change point of the second information. Are recorded so as to be shifted.

Here, the recording is performed so that the change point of the signal for pulling in the phase of the clock for signal processing of the second information and the change point due to the displacement in the width direction of the recording track do not overlap.

Also, in the recording method of the optical disk according to the present invention, the recording track is preliminarily recorded while being displaced in the width direction of the recording track based on the first information including the frame synchronization signal, and is recorded along the recording track direction. A plurality of frames constituting a recording unit of main information recorded by using an optical disc composed of a data part and a frame synchronization signal part provided preceding the data part, and the optical disc is formed on the recording track. When recording the second information including the signal for pulling in the phase of the clock for signal processing in the frame synchronization section along the line, the change point due to the displacement in the width direction of the recording track and the change point of the second information Are recorded so as to be shifted.

Further, in the reproducing method of the optical disk according to the present invention, the recording track is preliminarily recorded by being displaced in the width direction of the recording track based on the first information including the frame synchronization signal, and the signal processing is performed along the recording track direction. An optical disc which is recorded such that a change point caused by a displacement in the width direction of the recording track and a change point of the second information are shifted when recording second information including a signal for pulling in a phase of a clock for recording. The first information is reproduced from an output of the irradiated optical beam that has detected the return light from the optical disk, and a PLL circuit of the PLL circuit is reproduced based on the reproduced frame synchronization signal of the first information. After the pull-in of the PLL circuit is completed, the second information is reproduced from the output of detecting the return light from the optical disk, and the second information is reproduced.
In the PLL circuit based on the above-mentioned information.

F. Function According to the recording method and the reproducing method of the optical disk according to the present invention, for example, when recording (reproducing) information (data) on a magneto-optical disk, the signal recorded and formed by the displacement in the track width direction is used to reduce the frequency of the PLL. Do the retraction,
When the phase of the PLL is pulled in by a signal recorded on the track, for example, a clock synchronization signal, the influence of the signal recorded and formed on the displacement in the track width direction with respect to the phase pulling in of the PLL can be removed.

G. Examples Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a recording format of a recording track of a magneto-optical disk formed by one embodiment of a signal recording method according to the present invention, together with recording information by displacement in a track width direction. The magneto-optical disk used in this embodiment is formed by, for example, forming a perpendicular magnetization film having a magneto-optical effect on a transparent substrate, and a guide groove for tracking is formed on the magneto-optical disk in a spiral shape. It is formed concentrically in advance (a so-called pre-groove), and the pre-groove or a land between the grooves is used as a recording track. Also, this recording track
For example, a baseband signal of read-only secondary information including at least a control signal (synchronization, clock, etc.) is recorded and formed in advance by a track width direction displacement (track width direction shift or track width direction modulation). ing. When the main information is recorded along a track direction on a recording track on which a secondary information signal is recorded and formed in advance by the displacement in the track width direction, the change point of the recorded signal is in the track width direction. The main information is recorded so as not to overlap the change point of the signal recorded in advance due to the displacement.

In FIG. 1, as a specific example of the recording format of the recording information based on the displacement in the track width direction, a so-called CD (compact disk) format block or frame structure is used. That is, one block (one sector) serving as an information recording unit starts from the 0th frame to the 0th frame.
Consisting of 98 frames up to 97 frames, one frame is the channel clock cycle (channel clock bit width)
At 588 times T (588T), each frame is provided with a recording area for a 24T synchronization signal, a 14T subcode, and 544T data (including parity), and each area is connected with 3T connection bits. Have been. In the synchronization signal area, a frame synchronization signal in CD format, that is, an inversion interval of 11
A sync signal that is continuous twice at T is arranged, and the inversion interval is set to, for example, 7T, 11T (= 7T + 4T), and 4T, thereby configuring 44T of the top of the frame including the frame synchronization pattern of 22T. The frame synchronization signal is used to synchronize in frame units. To synchronize in a block (sector) unit composed of a plurality (98) of these frames, the frame synchronization signal is used. 8T at the end of the first 44T
May be used as a sector mark (block mark) for block synchronization. For example, the sector mark of the frame at the head of the block (the 0th frame) has a shape rising at the center of 8T, that is, a so-called PE.
By writing "0" in the (phase encoding) method and writing "1" in the sector mark of the other frames, the block top frame can be distinguished from other frames.

In one 588T (channel bits) of one frame, the other 544T data area of the 44T synchronization area at the beginning of the frame stores, for example, secondary information such as address information and the like in the main information channel clock cycle T of the main information. Integer multiple period (for example,
Recording may be formed by displacement in the track width direction with reference to the clock of 8T). As the modulation method at the time of the displacement recording in the track width direction, the above-mentioned PE method, so-called bi-phase mark modulation method, EFM (8-14 modulation) method, or the like may be adopted. Here, when recording is performed in the track width direction by the PE method of 1T of 8 bits, 68 (= 544/8) bits of information can be recorded in the data area of 544T. When recording an address as 68 bits of information per frame, for example, according to the CD format,
It is conceivable to use eight bits corresponding to two decimal digits in BCD representation for each of the minute, second, and block addresses. At this time, 2 bits are used for the sector mark, and minutes, seconds,
If 8 bits are used for each address of the block and the frame, a total of 34 bits is obtained from 2 + 8 × 4, and these inverted data are arranged successively to the 34-bit address data to make a total of 68 bits. be able to.

As described above, as a specific example of a recording format of main information recorded along a track direction on a recording track on which sub-temporal information such as a synchronization signal is recorded and formed by displacement in the track width direction, a so-called CD (compact) is used. Disc) format. That is, in FIG. 1, one block (one sector) serving as an information recording unit is composed of 98 frames from a 0th frame to a 97th frame, and one frame is 588 times (channel clock cycle (channel clock bit width)) T (channel clock bit width) T. 588T), one frame is provided with recording areas for synchronization signals, subcodes, and data (including parity). That is, at the beginning of one frame, a 24T (24 channel bits) synchronization signal area and a 14T subcode area are provided, and these are connected via 3T connection bits, respectively. The sample data and the parity data of the symbol (32 bytes) are modulated and arranged by the so-called EFM (8-14 modulation) method. The first frame of one block, that is, the 24T synchronization signal area, the 3T connection bit, and the 14T subcode area of the 0th frame have a 3T signal as a signal for pulling in the clock phase during recording and reproduction.
A pattern in which the reversal interval of 13 is repeated 13 times is recorded.
Further, a pattern in which the 11T inversion interval is continuous twice is recorded in the 24T synchronization signal area of the first frame to the 97th frame. This pattern in which the inversion interval of 11T is repeated twice is a so-called out-of-pattern that is not in the above-mentioned EFM method, and is used for frame synchronization.

As described above, the inversion interval of the signal recorded by the track width direction displacement recording is set to 11T, 11T, 7T, 11T (= 7T + 4
T), 4T, and the inversion interval of the synchronization signal for pulling in the phase of the clock recorded on the recording track of the 0th frame along the track direction is nT, and the integral multiple of nT is 11T, 22T.
(= 11T + 11T), 29T (= 22T + 7T), 40T (= 29T + 11)
T) and 44T (= 40T + 4T) are not equal to each other. For example, by setting 3T (n = 3) as in the above specific example, the change point of the signal recorded in the track width direction displacement as shown in FIG. The change points of the signal recorded on the recording track can be prevented from overlapping. It should be noted that the inversion interval of the synchronization signal for pulling in the phase of the clock recorded on the recording track of the 0th frame along the track direction is set to an integer other than 3T and an integer of T (n )
The value may be a double value, for example, 4T. By preventing the change point of the signal recorded due to the displacement in the track width direction and the change point of the signal recorded on the recording track from overlapping each other, the track width can be reduced with respect to the phase pull-in of the PLL as described later. It is possible to remove the influence of the change point of the recorded signal due to the directional displacement.

As described above, a specific example of reproducing a magneto-optical disk on which a synchronization signal is recorded on a recording track and secondary information such as an address is recorded and formed by displacement in the track width direction will be described with reference to FIG. I will explain it.

In FIG. 2, the magneto-optical disk 10 has a spiral or concentric recording track on which the secondary information is recorded and formed by displacement in the track width direction.
The synchronization signal and the main information are recorded on the recording track as described above. The magneto-optical disk 10 is rotated by a spindle motor 11 at a constant linear velocity (CLV) or a constant angular velocity (CAV). Record /
A laser beam from a laser light source 12 (such as a laser diode) for reproduction is converted into a parallel light beam by a collimator lens 13, and then passes through a beam splitter 14, and an objective lens 15 of a so-called two-axis device for focusing and tracking. Then, the light is irradiated onto the magneto-optical disk 10. The reflected beam from the magneto-optical disk 10 is split by a beam splitter 14 and passed through an optical system 16 such as a half-wave plate, a converging lens, and a cylindrical lens.
It is incident on 17. In the polarizing beam splitter 17, the light is separated into a so-called P-polarized light component and an S-polarized light component, and is incident on photodetectors 18 and 19 for detecting a tracking error signal, a focus error signal, and a magneto-optical signal (MO signal).

The outputs from the photodetectors 18 and 19 are sent to a differential amplifier 20 to take a difference to extract a magneto-optical signal (MORF signal). The MORF signal from the differential amplifier 20 is switched to a selected terminal of a switch 22. b and MO data detection circuit 21
Sent to. The photodetector 18 also detects a tracking error signal and a focus error signal using, for example, an element having a light-receiving portion divided into four parts. It is possible to obtain a signal of the secondary information recorded by the displacement (an RF signal recorded in the width direction). The track width direction displacement recording signal (RF of width direction recording) extracted as a high frequency component of this tracking error signal
Signal), as described above, includes a clock signal component having the same frequency as the clock of the main information recorded on the recording track along the track direction, and a synchronization signal for each predetermined recording unit of the main information. (For example, a frame synchronization signal), the track width direction displacement recording signal is switched to the PLL through the selected terminal a of the switch 22.
(Phase Lock Loop) 23, clock recovery and generation of various timing signals are performed by sending them to a frame synchronization detection circuit, a timing generation circuit, and the like. That is, this
The PLL 23 includes a phase comparator 23a, an LPF (low-pass filter) 23
b, comprising a VCO (voltage controlled oscillator) 23c and a frequency divider 23d, controlling the oscillation frequency of the VCO 23c to be an integral multiple of the frequency of the clock included in the RF signal recorded in the width direction. , It is possible to reproduce a clock having the same frequency as the frequency of the clock included in the RF signal recorded in the width direction. Then, a clock of a predetermined frequency from the PLL 23 is sent to a frame synchronization detection circuit, a timing generation circuit, and the like, and the frame synchronization is pulled in and various timing signals are generated. Next, after the pull-in of the clock frequency of the PLL 23 is completed using the RF signal of the width direction recording, the switch 22 is switched by a switching control signal from, for example, a timing generation circuit, and the MORF signal is sent to the PLL 23. Then, with the synchronization signal written at the beginning of the 0th frame included in the MORF signal, the phase of the PLL 23 is pulled in, the clock with the phase pulled in is sent to the MO data detection circuit, and the clock is recorded on the recording track. The main signal (data) is detected and taken out by the terminal 25 as reproduction data.

By the way, when the phase of the PLL 23 is pulled in by the synchronization signal recorded on the recording track as described above, the signal recorded due to the displacement in the track width direction leaks into the MORF signal, causing an adverse effect. For example, as shown in FIG.
In B, C, etc., when the change point (edge) of the magneto-optical signal (MO signal) recorded on the recording track overlaps with the change point (edge) of the signal recorded due to the displacement in the track width direction, the phase of the PLL 23 is pulled in. Accuracy was getting worse. That is, in the phase comparator 23a of the PLL 23, the change point of the signal recorded in the track width direction displacement affects the change point of the synchronization signal recorded on the recording track, and for example, jitter occurs in the synchronization signal. The output of the phase comparator 23a fluctuated. Therefore, in the signal recording method according to the present invention, as shown in FIG. 1, for example, the change point of the MO signal recorded on the recording track is shifted from the change point of the signal recorded by the displacement in the track width direction to change the track width. The influence of the signal recorded due to the direction displacement is eliminated, and the phase pull-in accuracy of the PLL 23 is increased.

Here, another embodiment of the signal recording method according to the present invention will be described with reference to FIG. FIG. 4 is a diagram showing a recording format of a recording track of a magneto-optical disk formed according to another embodiment, together with recording information by displacement in a track width direction. As shown in FIG. 4, the phase of the signal recorded on the recording track is shifted by a unit, for example, 0.5 T smaller than the channel clock period (that is, the channel clock bit width) T with respect to the signal recorded by the displacement in the track width direction. The point of change of the signal recorded in the track width direction displacement and the point of change of the signal recorded on the recording track should not overlap, and the phase pull-in of the PLL should be performed accurately as in the above embodiment. it can. in this case,
Also in the data area, the change point of the signal on the recording track and the change point of the track width direction displacement recording signal do not overlap, so that the influence of the track width direction recording signal can be eliminated.

Note that the present invention is not limited to the above-described embodiment, and the phase shift amount of a signal recorded on a recording track with respect to a signal recorded due to a displacement in the track width direction may be, for example, 0.1T or 0.2T.
You may make it. That is, the positional accuracy (deviation) of the signal recorded on the recording track is, for example, a channel clock cycle (channel clock bit width) T of
At 0 ns, it is about ± 20 ns, and the amount of phase shift of the signal recorded on the recording track with respect to the signal recorded due to the displacement in the track width direction is set to a sufficiently large value compared to this accuracy, and the mutual change point is What is necessary is just to avoid overlapping.

In general, when recording a magneto-optical signal (MO signal) on a recording track, a clock component is reproduced from a signal recorded in advance by displacement in the track width direction, and the MO signal is reproduced on the recording track using this clock. The method of recording is used, but due to the delay of filters such as PLL for clock recovery and the circuit for writing MO signals,
The MO signal recorded on the recording track is delayed from the signal recorded in advance by the displacement in the track width direction. That is, the clock phase of the MO signal on the recording track is different from the clock phase of the signal recorded in advance in the track width direction displacement recording, and the clock phase is mainly determined by using the clock extracted from the signal recorded in advance in the track width direction displacement recording. When information is reproduced, an error may occur. Therefore, in order to reproduce the magneto-optical disk, it is necessary to extract a clock component from the MORF signal obtained by reproducing the MO signal, and reproduce the main information using the clock. In other words, it is necessary to provide a long preamble area in which a clock component is written on the recording track so that the clock component can be sufficiently extracted from the MO signal. Therefore, in the present invention, instead of providing a sufficiently long preamble area for extracting a clock component, for example, as shown in FIG. 1 or FIG. The clock signal of the PLL is pulled in by this recorded signal, and the clock phase of the PLL can be pulled in by the synchronization signal written at the beginning of the 0th frame on the recording track. While shortening
The PLL pull-in time is shortened.

As described above, in the present invention, a signal including the clock component of the main information is recorded and formed in advance by the displacement recording in the track width direction, and the phase (displacement point) is shifted with respect to the signal so that the phase pull-in is performed on the recording track. By recording the synchronization signal as, for example, a magneto-optical signal, the PLL clock frequency is preliminarily pulled in with the track width direction displacement recording signal, and the PLL clock phase is pulled in with the synchronization signal recorded on the recording track, thereby stabilizing the PLL. In addition, the time required to perform the operation can be shortened, and by removing the adverse effect of the track width direction displacement recording signal on the signal recorded on the recording track, the clock of the PLL can be more accurately obtained. Furthermore, compared to a method in which clocking is performed only with a main information signal recorded on a recording track, the preamble for clock reproduction that must be recorded on the recording track can be reduced, and the recording capacity of the entire recording medium can be reduced. It can be prevented from lowering.

Further, in this way, a medium such as an optical disk on which information such as synchronization and address is recorded in advance by the displacement of the recording track itself in the width direction is easily mass-produced through a pressing process using a master disk or a stamper at the time of manufacturing the disk. Is possible.

The present invention is not limited to the above embodiments. For example, the recording medium may be, for example, an organic dye optical disk, various write-once disks, an overwritable disk, an optical card, a magneto-optical card, etc., in addition to the magneto-optical disk. Applicable. Further, software program data or the like may be recorded by the displacement in the track width direction. Further, the recording format of the main information and the track width direction displacement recording information is not limited to the specific example of FIG. 1 or FIG.

H. Effects of the Invention As described above, according to the present invention, a recording track is formed on an optical disc by displacing the recording track in advance in the width direction of the recording track with the first information including a frame synchronization signal. By performing recording so that the change point of the second information including the signal for pulling in the phase of the clock for signal processing along the track and the change point due to the displacement in the width direction of the recording track are shifted, that is, are not overlapped, the recording is performed. When the change point of the second information recorded along the track and the change point of the first information overlap, it is possible to prevent the occurrence of jitter in the synchronization signal and the deterioration of the phase pull-in accuracy of the PLL circuit.

Further, it is not necessary to provide an extra preamble area on the recording track in order to reproduce the clock for reproducing the main information.

[Brief description of the drawings]

FIG. 1 is a diagram showing a recording format of an embodiment of a signal recording method according to the present invention, and FIG. 2 is a block circuit diagram showing a specific example of a signal reproducing apparatus for reproducing a magneto-optical disk to which the present invention is applied. FIG. 3 is a diagram showing a specific example when a change point of a track width direction displacement recording signal and a change point of a signal recorded on a recording track overlap, and FIG. 4 is a signal according to the present invention. FIG. 11 is a diagram illustrating a recording format of another embodiment of the recording method. 10 magneto-optical disk 18, 19 photo detector 21 MO data detection circuit 22 changeover switch 23 PLL

Claims (4)

(57) [Claims] 1. An optical disk in which a recording track is pre-recorded by being displaced in a width direction of the recording track based on first information including a frame synchronization signal, and a signal processing is performed on the optical disk along the recording track. When recording the second information including the phase pull-in signal of the clock for
A recording method for an optical disc, wherein recording is performed such that a change point due to a displacement in the width direction of the recording track and a change point of the second information are shifted. 2. The recording method according to claim 1, wherein the change point of the signal for pulling in the phase of the clock for signal processing of the second information and the change point of the recording track due to displacement in the width direction do not overlap. 2. The recording method for an optical disk according to claim 1, wherein: 3. The main information recorded along the recording track direction while the recording track is displaced in the width direction of the recording track based on the first information including the frame synchronization signal and recorded in advance. A plurality of frames constituting a recording unit of an optical disk composed of a data part and a frame synchronization signal part provided preceding the data part are transmitted to the frame synchronization part along the recording track on the optical disk. An optical disc for recording the second information including a signal for pulling in a phase of a clock for signal processing, so that a change point due to a displacement in a width direction of the recording track and a change point of the second information are shifted from each other; Recording method. 4. A recording track is displaced in a width direction of the recording track based on first information including a frame synchronization signal and is recorded in advance, and a phase for pulling in a clock for signal processing along the recording track direction. When recording the second information including the signal of the above, a light beam is irradiated on the optical disc which is recorded so that the change point due to the displacement in the width direction of the recording track and the change point of the second information are shifted, The first information is reproduced from an output of the irradiated optical beam that detects return light from the optical disk, and a PL is generated based on a frame synchronization signal of the reproduced first information.
After the L circuit is pulled in, after the pull-in of the PLL circuit is completed, the second information is reproduced from the output of detecting the return light from the optical disk, and based on the clock pull-in signal of the second information. A method for reproducing an optical disk, wherein the phase of the PLL circuit is pulled in by the above method.