JPH05135507A - Optical disk and recording/reproducing system thereof - Google Patents

Abstract

PURPOSE:To properly secure the rotational synchronization by deciding exactly a header segment. CONSTITUTION:An optical disk is provided with a 1st mark (PMAD) which shows that a header segment is identical with a segment which includes the address information at a prescribed position in a segment. Furthermore a ROM data segment and a RAM data segment are provided with the 2nd marks (PMR and PMMO or PMD) at the setting positions different from the 1st mark in a segment to show absence of at least the header segment.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a ROM area and RA
An optical disc having an M area (magneto-optical recording area);
The present invention relates to a recording / reproducing system for this optical disc.

[0002]

2. Description of the Related Art An optical disk system capable of irradiating a spiral track with a laser beam to record various data on an optical disk and reading the recorded data is a track on which data on the optical disk is arranged. There are known a continuous system in which the tracks are formed by pregrooves and a sampled servo system in which tracks for arranging data are formed by sample servo pits that are discretely arranged.

FIG. 10 shows an example of a format of a ROM mixed type magneto-optical disk in which a recording track is formed by sample servo pits. S _{1 to} S ₄₂
Indicates a sector that is divided into 42 in the circumferential direction, for example.

FIG. 11 shows a track in each sector unit.
As shown in (a), a header segment H ₁ which is an area in which address data is recorded with pits formed in advance by embossing or the like is provided, and then a header segment H ₂ is provided. There are various usage modes of the header segment H ₂ depending on the format. For example, the header segment H ₂ is used as a test writing area immediately before data recording / reproducing is performed as a magneto-optical (MO) recording area, or as a ROM area. There is a case where predetermined data is formed by embossed pits.

Further, following the header segment H ₂ , a data recording area DB capable of recording data of, for example, 20 bytes is divided into ₃₀ data segments SG _{1 to} SG ₃₀ . This data segment SG ₁
The area consisting to SG ₃₀ in the optical disc,
The area where the data can be written / read out in the MO area (RAM area) and the RO formed by embossed pits
There is a portion which is regarded as an M region and is only capable of reading data.

In the MO region, when the recording surface is irradiated with a laser beam along the track and a magnetic field is applied from the other surface of the magneto-optical disk, the magnetic field is applied when the recording surface reaches the Curie point or higher. It is magnetized in the direction of the magnetic field and the data is recorded. Further, when reading information from a magneto-optical disk on which data is recorded, recorded data is read by detecting reflected light of a laser beam by utilizing a magnetic cover effect.

In each data segment (SG _{1 to} SG ₃₀ ) or header segment H ₁ or H ₂ , as shown in FIG. 11 (b), a servo byte SB is arranged first, followed by an address and a ROM. An area for recording data and MO data is formed.

At least one pair of wobbling pits P ₁ and P ₂ which are displaced from the center of the track T to the outer peripheral side and the inner peripheral side are arranged on the servo bite SB and on the center line of the track T. The clock pit P ₃ is previously formed by embossing or the like. Further, as a pit P _4, P ₅ the access code indicating the track information to form a Gray code, are formed in the same manner. or,
Warbling pits P ₁ and P ₂ and clock pits P
_A mirror surface M is formed at the rear portion of the mirror ₃ , and the focus servo signal is detected by the laser light reflected from the mirror surface M, and the laser power can also be controlled.

In such a magneto-optical disk, a tracking error signal is usually formed by calculating reflected light when the wobbling pits P ₁ and P ₂ are detected at the sampling points t ₁ and t ₂ , and the clock pit P is formed. _The signal that detects ₃ at sample point t ₃ forms the master clock signal.

[0010]

By the way, in such a ROM / MO mixed type optical disc, as the classification of the segment unit in the optical disc, the address region (header segment H ₁ ) and the ROM data region (R
OM data segment) and MO data area (RA
M data segments) exist, but after the PLL lock is achieved and the master clock is obtained, the system must be located at least at the beginning of each sector in order to achieve rotational synchronization such as sector synchronization and segment synchronization. It is necessary to detect the header segment H ₁ which is
That is, rotation synchronization is realized by detecting the header segment H ₁ and obtaining segment synchronization. Therefore,
During the recording / reproducing operation, it must be accurately determined whether the current scan area is the header area. Needless to say, the ROM area and the MO area must be accurately discriminated in the recording / reproducing operation.

Therefore, in the conventional optical disk, a mark (ROM mark) is formed at a predetermined position of the servo byte SB in the ROM data area, for example, by an embossed pit.
The segment type determination operation is performed depending on whether or not the area (data storage area DB) following B is recorded by embossed pits. In other words, header (address area) --- ROM mark without + emboss pit ROM data area --- ROM mark + emboss pit-MO data area・ ・ ・ ・ ・ ・ It is possible to discriminate by the difference of no ROM mark + no emboss pit.

Here, the initial startup sequence of the sampled servo system will be described. First, focus servo (continuous focus servo) control is performed, and then PLL lock is applied. Then, after the PLL is locked and the servo byte SB is specified, the sector synchronization,
Rotation synchronization control such as segment synchronization is performed, and focus servo (sampled focus servo) control is performed in the optical head servo system. Further, in the optical head servo system, tracking servo control is performed after focus servo control. In such an initial start-up sequence, the tracking-on state is not always obtained at the stage of performing the rotation synchronization control.

In the state where the tracking is not turned on, the reproduction RF signal level due to the ROM mark naturally becomes small, so that it becomes very difficult to determine the presence or absence of the ROM mark. In addition, if the playback signal is affected by noise or a defect before the tracking is turned on, the ROM
It is more difficult to determine the presence or absence of the mark.

There is also an optical disk of the type in which guard bands are formed on both sides of the track in the MO area. However, since this guard band is usually formed slightly protruding up to the servo byte SB, it is distinguished from the ROM mark. It may be difficult, and this also increases the difficulty of determining the presence or absence of the ROM mark.

That is, the conventional method has a drawback that the ROM mark determination is inaccurate, which causes a problem that the type of each segment cannot be accurately detected and rotation synchronization cannot be correctly obtained. there were.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, in which concentric or spiral tracks are formed by being divided into a plurality of sectors. In an optical disc in which a header segment in which address data is recorded, a ROM data segment in which ROM data is recorded, and a RAM data segment in which data can be recorded and reproduced exist as segments in a sector ,
The header segment is provided with a segment having address information at a predetermined position in the segment, that is, a first mark indicating that it is the first segment in the sector, and in the ROM data segment and the RAM data segment The optical disc is provided such that at least a second mark indicating that it is not a header segment is provided at a setting position different from the first mark in the segment.

As a recording / reproducing system for this optical disc, the reproduction information of the first and second marks is obtained by detecting the difference between the reproduction signals, and the header segment is discriminated from the obtained mark information. is there.

[0018]

By detecting the difference in the mark position, not by detecting the presence / absence of the mark, influences such as tracking on / off, noise, and defects can be excluded from the mark detection operation, and the accuracy of the determination is Remarkably improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical disc of the present invention will be described below with reference to FIGS. The sector structure of the optical disc is the same as that shown in FIG.
FIG. 1 shows a portion of the servo byte SB in the address area (header segment H ₁ ), FIG. 2 shows the servo byte SB in the ROM data segment, and FIG. 3 shows MO.
The portion of the servo byte SB in the data segment is shown. In each figure, T is a track, P ₁ , P
₂ is a pair of wobbling pits that are offset from the center of the track T toward the outer and inner sides, P ₃ is a clock pit located on the center line of the track T, and P ₄ and P ₅
Is a pit forming a gray code indicating track information. Further, M indicates a mirror surface.

The 1st to 40th pits are used as the servo bytes SB in each segment, and the 41st pit that follows is an area (address storage area or data storage area DB) in which various information is recorded. .. That is, in the header segment of FIG. 1, the address data AD is recorded by the embossed pits after the 41st pit, and in the ROM data segment of FIG.
Similarly, the OM data D _R is also N by the emboss pit.
It is recorded in the RZi system. Further, in the MO data segment of FIG. 3, the 41st and subsequent pits are used as a magneto-optical recording area so that predetermined data can be recorded / reproduced by the magnetic field modulation method.

Further, in the optical disc of this embodiment,
As can be seen from each figure, the third segment is included in the header segment H ₁ .
A pit is formed at the 8th pit and the address mark PM _AD
Thus, a pit is formed at the 40th pit in the ROM data segment to form the ROM mark PM _R, and a pit is formed at the 36th pit in the MO data segment to form the MO mark PM _MO . Reproduced RF signal waveforms obtained by scanning such segments are shown in the lower part of each drawing.

Therefore, for the optical disk of this embodiment,
If the position of the mark pit in the segment is detected, it is possible to determine whether the mark pit is the address mark PM _AD , the ROM mark PM _R, or the MO mark PM _{MO, and} whether the scanning segment is the header segment. , ROM data segment or MO data segment can be identified.

An embodiment of a recording / reproducing system for such an optical disc will be described with reference to FIGS. FIG. 4 is a schematic diagram of a recording / reproducing circuit to which the recording / reproducing system of the present embodiment is applied. Reference numeral 1 is a magneto-optical disk having the track format described in FIGS. The magneto-optical disk 1 is rotated by a spindle motor 2 at a constant angular velocity (CAV), for example. An optical head 3 for irradiating a laser beam during recording or reproduction is arranged below the magneto-optical disk 1.

As is well known, the optical head 3 is composed of an optical system including a laser emission source, a collimator lens, a beam splitter, and a biaxial device for controlling an objective lens. It is equipped with a polarizing beam splitter and a detector for detecting In particular, the reflected light is split into a P-polarized component and an S-polarized component by the polarization beam splitter 3C and detected by the two detectors 3A and 3B.

Then, the outputs of the detectors 3A and 3B are supplied to the arithmetic circuit 4a, and the arithmetic circuit 4a takes the difference between the two outputs to extract the reproduction signal of the magneto-optically recorded data. The outputs of the detectors 3A and 3B are supplied to the arithmetic circuit 4b, and the arithmetic circuit 4a calculates the sum of both outputs to obtain the RO recorded by the embossed pits.
A reproduction signal of M data can be extracted.

Further, the detector 3A is, for example, a light receiving element having a division surface, and when the servo byte SB of each segment is scanned, the push-pull signal is extracted by the detection circuit 5 to form various servo signals. Then, the servo circuit 6 is driven to drive the biaxial device to perform tracking servo and focus servo, and at the same time, the control data reproducing circuit 7 is supplied to form a master clock signal and the like, and the master clock signal is generated. Output to the system control unit 8. Reference numeral 9 denotes a spindle servo circuit which, under the control of the system control unit 8, controls the rotation operation of the spindle motor 2 by CAV using, for example, an FG pulse.

Further, in the control data reproducing circuit 7,
For the reproduced signal from the supplied servo bite SB,
The difference detection method is executed to detect the position of the mark pit in the segment, and the mark pit is the address mark PM.
_It is determined whether it is _AD , ROM mark PM _R, or MO mark PM _MO . The discrimination information is supplied to the system control unit 8 and used as reference data for rotation synchronization control or the like. Further, in the control data reproducing circuit 7, the servo byte SB in the header segment H ₁
Extract the address information recorded in the area following
This is supplied to the system control section 8.

Reference numeral 10 denotes a signal processing circuit for the reproduced signal demodulated by the differential amplifiers 4a and 4b, and includes an AGC circuit for controlling the amplitude of the reproduced signal to be constant. Reference numeral 11 is a clamp circuit for the reproduction signal read from the magneto-optical disk 1. The clamp voltage E _C supplied to the clamp circuit 11 removes a DC offset component superimposed on the reproduction signal. The "0" level is set to a constant voltage.

Reference numeral 12 denotes a gain adding circuit. In this gain adding circuit 12, the reproduced signal is an A / D converter 1 described later.
The amplitude level is adjusted to some extent suitable for the dynamic range of 3 in FIG. Reference numeral 13 is an A / D converter, and the output of this A / D converter 13 is supplied to a data detection section 15 composed of a digital circuit via a difference detection circuit 14.

That is, for example, NRZi recorded in the area following the servo byte SB on the optical disk 1 is recorded.
The reproduction information of the ROM data and MO data according to the system modulation method is extracted by the decoding process in the data detection unit 15. And this ROM data segment, M
Reproduction data of ROM data or MO data extracted by scanning the O data segment is supplied to a reproduction processing circuit (not shown).

On the other hand, the magneto-optical disk 1 is provided with a magnetic head portion 30 at a position facing the optical head 3.
A magnetic field that is inverted by the recorded data is applied. That is, the recording data supplied from the terminal 31 is subjected to predetermined code modulation and blocking in the recording data processing unit 32, further error correction code and the like are added, and the recording data is supplied to the magnetic head 30 as recording data. ..

In the control data reproducing circuit described above, for example, a difference detecting circuit is configured as shown in FIG. 5 to detect a pit position difference, and the pit position information is supplied to the system control section 8.

That is, the reproduction RF signal for scanning the servo byte SB is digitized by the A / D converter 40 and input to the maximum value register 41. On the other hand, from the counter 42a of the timing controller 42, as shown in FIG.
Values corresponding to the pit positions (1st to 40th pits) shown in (4) are output based on the master cloak, and are input to the pit position register 43.

The data held in the register 41 is successively compared with the value input via the A / D converter 40 in the comparator 44, and the comparison information output is supplied to the timing controller 42. The timing controller 42 outputs the comparison information to output the A / D converter 40.
When it is detected that data larger than the data held in the register 41 is input from the registers 41, 4
3 to control the update operation.

That is, in the servo byte SB of each segment of the optical disc 1, when the reproduction RF signal of the area of the 36th pit to the 40th pit is input to this difference detection circuit, the reproduction RF signal is generated by the mark pit.
Information on the point where the maximum value of the signal is obtained is stored in the registers 41 and 4.
Held at 3. That is, the register 41 holds the maximum value of the reproduction RF signal, and the register 43 stores the reproduction RF signal.
The pit count value at the point where the maximum value of the signal is obtained is held. That is, the position information of the mark pick is obtained from the register 43.

In the recording / reproducing system of the present embodiment, the above-mentioned FIG.
Since the position detection operation of the mark pits (PM _AD , PM _R , PM _MO ) is performed on the optical disc 1 shown in FIG. 3, the mark pit is detected at the 38th pit in the segment being scanned. For example, if the header segment and the mark pit are detected at the 40th pit, it can be determined as the ROM data segment, and if the mark pit is detected at the 36th pit, it can be determined as the MO data segment.

By adopting the method of making the segment discrimination based on the position of the mark pits instead of the presence or absence of the mark pits, the discrimination operation is not easily influenced by the presence or absence of noise, etc., and is required for more accurate discrimination. The tracking-on state is no longer required. Therefore, the accuracy of segment discrimination is significantly improved.

Therefore, the scanning timing (position) of the header segment can be accurately grasped from the segment discrimination information, and the rotation synchronization can be properly applied. of course,
It is possible to accurately discriminate between the ROM data segment and the MO data segment, and the discrimination information can be effectively used as the control information of the recording / reproducing operation.

As shown in FIGS. 1 to 3, in the optical disc of this embodiment, the position of the mark pits is MO mark PM _MO (36th pit) and address mark PM _AD (38th) from the segment head direction. Pit), ROM mark P
It is set in the order of M _R (40th pit).

The MO mark PM _MO is most distant from the data area because the pre-write area is provided immediately before the data area and the pre-write information is used for clamp control. This is to avoid the interference of.

When the ROM data is recorded by the NRZi system, there is no problem even if the ROM mark PM _R is close to the data area. Therefore, this is set at the end and the address mark pit PM _AD is set as the pit. It is preferable to set the address data for position recording so as to be separated from the data area in which the address data is recorded.

The mark pits are detected by the difference detecting circuit shown in FIG. 5, but the edge position difference detecting circuit is constructed as shown in FIG.
The position of the mark pit may be determined by detecting the rising edge of the F signal waveform (signal change amount).

That is, the reproduced RF signal for scanning the servo byte SB is digitized by the A / D converter 50 and input to the sequential register 51. On the other hand, the counter 52a of the timing controller 52 outputs a value corresponding to the pit position (first to 40th pits), which is input to the pit position register 53.

The data held in the register 51,
The value input via the A / D converter 50 is the subtractor 5
Subtraction processing is performed in 3. That is, a subtraction process is performed between the input signal and the input signal one sample before, and the difference amount (absolute value of the subtraction result) and the polarity (whether the rising portion or the falling portion of the reproduction signal) are determined. The difference amount output from the subtractor 54 is supplied to and held in the register 55. Further, the polarity determination signal S _P is supplied to the timing controller 52.

The value held in the register 55 and the value newly output from the subtracter 53 are compared in the comparator 56, and the comparison information output is the timing controller 5
2 is supplied. If the timing controller 52 detects that the data larger than the data held in the register 51 is input by the comparison information output, and that the rising edge is detected by the polarity determination signal S _P , the register is registered. The update operation of 53 and 55 is controlled.

That is, in the servo byte SB in each segment of the optical disc 1, if the reproduction RF signal of the area of the 36th pit to the 40th pit is input to this difference detection circuit, the reproduction RF signal of the mark pit is generated. The information of the point where the rising waveform is obtained, that is, the pit position information of the mark pit is obtained from the register 53. Therefore, it is possible to perform accurate segment determination as in the above.

FIGS. 7, 8 and 9 show other embodiments of the optical disk of the present invention.
This is an example when it is not necessary to distinguish between the OM data segment and the MO data segment. That is, at least the header segment is accurately discriminated, and the rotational synchronization is controlled by this discrimination information. In these embodiments, as for the header segment H ₁ , the address mark PM _AD is formed at the 38th pit of the servo byte SB as in FIG.

In the embodiment of FIG. 7, the servo byte S is used for both the MO data segment and the ROM data segment.
At the 36th pit of B, a mark pit (data mark PM _D ) indicating that it is a segment in which data is recorded instead of an address is provided. Therefore, if the mark pit is detected at the 36th pit by the pit position difference detection or the edge position difference detection, it is a segment in which data is recorded (or is recorded), and if it is detected at the 38th pit, the address is recorded. It is determined that the header segment has been deleted.

The embodiment of FIG. 8 corresponds to an optical disk of the type in which the guard band GB is formed in the MO recording area. As shown in the figure, in the MO data segment, the guard band GB projects to the servo byte SB up to a portion corresponding to the 36th pit. This guard band GB is used as a mark, and correspondingly, the 36th pit of the ROM data segment is used. A data mark PM _D is formed on.

Then, the MO data segment and the ROM
As shown in the figure, an effect of the guard band GB or a rising waveform due to the data mark PM _D is obtained corresponding to the 36th pit in the reproduced RF signal waveform when the servo byte SB of the data segment is scanned. On the other hand, when the header segment is scanned, a rising waveform due to the address mark PM _AD formed at the 38th pit is obtained. Therefore, the header segment can be discriminated by the edge position difference detection operation.

The embodiment of FIG. 9 also corresponds to an optical disc of the type in which the guard band GB is formed in the MO recording area, and the ROM data corresponding to the protruding portion of the guard band GB of the MO data segment to the servo byte SB. A long data mark PM _D is formed on the servo byte SB of the segment from the 36th pit to the 40th pit.

Then, the MO data segment and the ROM
As shown in the figure, an effect of the guard band GB or a rising waveform due to the data mark PM _D is obtained corresponding to the 36th pit in the reproduced RF signal waveform when the servo byte SB of the data segment is scanned. Then, when the header segment is scanned, a rising waveform due to the address mark PM _AD formed at the 38th pit is obtained, so that the header segment can be discriminated by the edge position difference detection operation.

Although various embodiments have been described above, the setting positions of the mark pits in the optical disc of the present invention and the circuit configuration in which the data recording / reproducing system of the present invention is adopted are not limited to these. Various changes are possible without using.

[0054]

As described above, in the optical disc and the recording / reproducing system thereof according to the present invention, the header segment has the first mark indicating that it is a segment having address information at a predetermined position in the segment. The ROM data segment and the RAM data segment are provided with at least a second mark indicating that the segment is not the header segment at a setting position different from that of the first mark in the segment. Since the segment discrimination is performed, there is an effect that segment discrimination, particularly header segment discrimination, can be accurately performed.
There is an advantage that the rotation synchronization control can be appropriately executed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a header segment of an embodiment of an optical disc of the present invention.

FIG. 2 is an explanatory diagram of a ROM data segment of the optical disc of this embodiment.

FIG. 3 is an explanatory diagram of MO data segments of the optical disc of this embodiment.

FIG. 4 is a block diagram of a recording / reproducing apparatus to which an embodiment of the recording / reproducing system of the present invention is applied.

FIG. 5 is a block diagram of a pit position difference detection circuit applied to this embodiment.

FIG. 6 is a block diagram of an edge position difference detection circuit applied to this embodiment.

FIG. 7: MO and R of another embodiment of the optical disc of the present invention
It is explanatory drawing of an OM data segment.

FIG. 8 is an MO and R of another embodiment of the optical disc of the present invention.
It is explanatory drawing of an OM data segment.

FIG. 9 is an MO and R of another embodiment of the optical disc of the present invention.
It is explanatory drawing of an OM data segment.

FIG. 10 is an explanatory diagram of an optical disc.

FIG. 11 is an explanatory diagram of a segment structure.

[Explanation of symbols] 1 optical disk 3 optical head 5 detection circuit 8 system control section PM _AD address mark PM _R ROM mark PM _MO MO mark PM _D data mark

Claims (2)

[Claims] 1. A concentric or spiral track is formed by being divided into a plurality of sectors, and a segment in the sector includes a header segment in which address data is recorded and ROM data. In an optical disc having a recorded ROM data segment and a RAM data segment capable of recording and reproducing data, the header segment has a head segment in a sector at a predetermined position in the segment. Is provided, and the ROM data segment and the RAM data segment indicate that they are not at least a header segment at a setting position different from that of the first mark in the segment. A second mark is provided Optical disc, characterized in that there. 2. A concentric or spiral track is formed by being divided into a plurality of sectors, and a segment in the sector includes a header segment in which address data is recorded and a ROM data. There is a recorded ROM data segment and a RAM data segment capable of recording and reproducing data, and the header segment is a head segment in a sector at a predetermined position in the segment. And a second mark indicating that the ROM data segment and the RAM data segment are not at least header segments at a setting position different from that of the first mark in the segment. For optical discs equipped with When performing the recording / reproducing operation, the reproduction information of the first and second marks is obtained by detecting the difference between the reproduction signals, and the header segment is discriminated from the obtained mark information. Optical disc recording / playback method.