JP3068093B2 - Optical disk and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disc, and more particularly, to a data format on an optical disc having a rewritable area and a read-only area.

[0002]

2. Description of the Related Art There are two types of optical disks: a read-only optical disk that only plays back recorded data, and a rewritable optical disk that allows a user to record data. In a read-only optical disk, a spiral or concentric track is provided on a disk substrate, and along this track, a physical unevenness (pit row) is formed according to information to be recorded. In a rewritable optical disk, a spiral or concentric groove is provided on a disk substrate, and a recording film is formed thereon. A track is set along this groove. When a user records data, a laser beam is irradiated along a track and, for example, the intensity of the laser beam is modulated according to the information to be recorded, thereby forming regions (recording marks) having different optical characteristics on the recording film. I do.

In general, in an optical disc, a track of one rotation is divided into a plurality of sectors (data units) as a unit for recording and reproducing data, so that the position of necessary data on the optical disc is managed, and data search is performed. I am trying to be fast.

[0004] The data format and modulation code of a read-only optical disk and a rewritable optical disk are different from each other. The data format of a rewritable optical disk is such that a user can record data for each sector. For example, an area for setting a laser power at the head of a recording area of each sector is provided, or a recording area is provided. It is necessary to provide a region for absorbing fluctuations in the rotation of the spindle motor at the end of the motor. On the other hand, a read-only optical disk does not need to cope with data rewriting by the user. Therefore,
In the case of a read-only optical disk, information recording at the time of manufacturing can be performed with high accuracy, and there is no need to provide an extra area for user recording unlike a rewritable optical disk.

FIG. 21 shows the structure of a conventional optical disc 301 having a rewritable area and a read-only area. The optical disc 301 has a recording film formed on a disc substrate so that a user can record and reproduce data. As shown in FIG. 21, on the optical disc 301, a reproduction-only area 302 provided on an outer peripheral portion thereof, a reproduction-only area 303 provided on an inner peripheral portion thereof, and a reproduction-only area 302 and 303 are formed. Rewriteable area 30
Five.

[0006] In the read-only areas 302 and 303, information and data are recorded in advance by forming a pit row 304 having a physically uneven shape. A groove-shaped guide track 306 is formed in the rewritable area 305, and the user records information and data while tracking a groove (groove: groove track) or land (inter-groove: land track) of this track. Reproduce.

FIG. 22 shows a conventional optical disk recording and reproducing apparatus 3 for recording and reproducing on and from the optical disk 301 of FIG.
FIG. 2 is a block diagram showing a configuration of a 00. As shown in FIG. 22, an optical disk recording / reproducing apparatus 300 includes an optical head 307 for recording or reproducing data, a first signal processing unit 320 for processing a reproduction signal from a rewritable area 305, and a reproduction-only area 302. Signal processing unit 330 for processing the reproduced signals from
And a switch 308 for switching and outputting the reproduction signal from 07 to the first and second signal processing units. The first signal processing unit 320 includes a first binarizing circuit 309, a first P
It has an LL (Phase-Locked Loop) 310, a first timing generation circuit 311, and a first demodulator 312.
The second signal processing unit 330 includes a second binarization circuit 313,
Second PLL 314, second timing generation circuit 31
5, and a second demodulator 316.

To reproduce the data recorded in the rewritable area 305, the switch 308 is switched to the terminal A on the first signal processing section 320 side. The reproduced signal is first converted to a digital signal by the first binarization circuit 309,
The clock is reproduced by the PLL 310 of FIG. next,
A gate signal for reading user data is generated by the first timing generation circuit 311 and the first demodulator 31
2 demodulates to binary data. The demodulated data is output from a first output terminal 317.

When reproducing data recorded in the read-only area 302 or 303, the conventional optical disk 30
As described above, since the format and modulation code of data recorded in the rewritable area 305 and the read-only areas 302 and 303 are different as described above, the second signal processing circuit 330 for the read-only area is used separately. There is a need.
Therefore, when reproducing data in the reproduction-only area 302 or 303, the switch 308 is switched to the B terminal on the second signal processing circuit 330 side. The reproduction signal is converted into a digital signal by the second binarization circuit 313 as in the case described above, and clock reproduction is performed by the second PLL 314. Next, a gate signal for reading user data is generated by the second timing generation circuit 315, and demodulated to binary data by the second demodulator 316. The demodulated data is output from the second output terminal 318.

FIG. 23 shows a conventional rewritable optical disk 3.
FIG. 2 is a diagram for explaining a data format in one sector 400 in FIG.

As shown in FIG. 23, a sector identification data area 401 is arranged at the head of a sector 400. Subsequently, a gap area 402 and a VFO area 403 are arranged, and thereafter, an information data area 450 and a buffer area 409 are provided. In the sector identification data area 401, address information and the like for managing the sector are recorded. The gap area 402 is an area for absorbing signal disturbance at the data recording start end and setting a recording laser power. Data to be recorded in the information data area 450 is divided into a plurality of data blocks 405a, 405b,...
a, 404b,... are added and recorded. Here, the data synchronization sequence 404 (404a, 404b,...)
..) Records a specific code pattern that does not occur in data in other areas modulated by the recording code. Also,
In the VFO area 403, a repeated pattern of codes having a single cycle is recorded, and the clock pull-in is stabilized during reproduction. The buffer area 409 absorbs rotation fluctuation at the end of recording.

According to the above-described data format, at the time of reproduction, first, the repetition pattern of the VFO area 403 stabilizes the pull-in of the clock in the PLL circuit. After the clock is sufficiently stabilized, the data synchronization sequence 404a is detected, it is recognized that it is the head of the information data area 450, and the first data block 405a is reproduced. Subsequently, the data synchronization sequence 404b is detected,
The next data block 405b is reproduced. Thereafter, by repeating the same operation, the data in the information data area 450 can be reproduced stably.

Also, as described above, the data block 405
By adding the synchronization sequence 404 every time, even if an error such as dropout occurs and the data reproduction is out of synchronization, it is possible to resume synchronization from the next data block and continue data reproduction. .

[0014]

However, in the structure of the conventional optical disk, the data format and the modulation code are different between the rewritable area and the read-only area as described above. Therefore, it is necessary to provide two signal processing circuits for the recording / reproducing apparatus for the optical disk, one for the rewritable area and the other for the read-only area, and there is a problem that the circuit scale becomes complicated and large.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an optical disc having a rewritable area and a read-only area. An object of the present invention is to provide a reproducible optical disk.

[0016]

The optical disk of the present invention comprises:
A rewritable first recording area and a read-only second recording area
An optical disc having a first recording area
Indicates the groove track and the land between the grooves.
Spiral or alternating tracks and tracks
A first track having a concentric shape;
The sector is divided into a plurality of first sectors, and the plurality of
Each of the first sectors has a sector identifying the first sector.
The first header area containing the
And a first data area for recording.
In the recording area, pit rows having physical irregularities are arranged.
Spiral or concentric second track
And the second track has a plurality of second sections.
Each of the plurality of second sectors.
Has a second data area in which read-only data is recorded.
And the first header area has a physical uneven shape.
Having a first pit row and a second having a physical unevenness
Pit string as the sector identification data,
Each of the pit train and the second pit train is
Half of the optical disk substantially equal to the width of the lube track
The first pit row has a radial width.
Pitch of the groove track from the center line of the groove track
About one-fourth of the optical disk toward the outer periphery of the optical disk.
And the second row of pits is
Of the pitch of the groove track from the center line of the groove track.
The position shifted in the inner circumferential direction of the optical disk by about 1/4
The first header area is formed on the optical disk.
Groove track and land adjacent to the disc in the radial direction
The first data area, which is provided in common with the rack;
And the data recorded in the second data area.
The read-only data obtained is modulated with the same modulation code.
The first data area and the second data area
With the same data capacity and same data format
Cage, thereby the objective described above being achieved. The plurality
Each of the first sectors includes the first header area and
A mirror mark disposed between the first data area and the first data area;
An area, a gap area, and a first dummy data area;
The first data area and the header area of the next first sector
Disposed between the band, the guard data area and buffer
And a key region. The first dummy
The data area is the modulation used to modulate the data to be recorded.
It may have a specific arrangement pattern of the key code. Departure
The reproducing apparatus of the present invention is a reproducing apparatus for reproducing the optical disc described above.
The first recording area in the first recording area.
A first detection unit for detecting a signal from the
Signal from the first data area in one recording area
And a second data area in the second recording area
A second detection unit for detecting the signals from the first detection unit and the second detection unit.
Selectively one of the output and the output of the second detector.
And a switch for outputting to the switch based on the output of the switch.
And a reproducing unit for generating a reproduced signal by
Thus, the above object is achieved.

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) In an optical disc according to the present embodiment, a recording film is formed on a disc substrate so that a user can record and reproduce data. As shown in FIG. 1, an optical disc 1 according to the present embodiment has a read-only area 2 provided on an outer peripheral portion thereof, a read-only area 3 provided on an inner peripheral portion thereof, and a read-only area 2 provided between the read-only areas 2 and 3. The formed rewritable area 5
have.

In the read-only areas 2 and 3, tracks are formed by physically uneven pit rows arranged spirally or concentrically. Each pit in the pit row is formed with a pit length and an arrangement according to the read-only data recorded in the read-only areas 2 and 3. In the rewritable area 5, spiral or concentric guide grooves (guide tracks) are formed on the disk substrate.
6 are formed. Information and data are recorded on a groove track, which is a groove of the guide groove 6, and a land track, which is a space between the grooves. The groove track and the land track are collectively referred to as an information track. FIG. 1 shows a spiral track in any area.

The information track of the rewritable area 5 is divided into a plurality of sectors. Each sector is composed of a first header area including identification data for identifying the sector and a recording mark having changed optical characteristics of a recording surface. And a first data area in which user data is recorded. Similarly, in the read-only areas 2 and 3, the track is divided into a plurality of sectors, and in each sector, read-only data is recorded by a second header area including identification data for identifying the sector and a pit string. And a second data area. As described above, by dividing the track of one rotation of the optical disc into a plurality of sectors (data units), it is possible to perform a required data position management and a data search based on the sectors at a high speed.

FIGS. 2A to 2H are views for explaining the data format of the optical disc 1 according to the present embodiment. First, the data format of the rewritable area 5 will be described. FIG. 2A shows each sector 1 of the rewritable area 5.
0 shows an example of a data format, and FIG. 2C shows a physical shape of a corresponding information track. In FIG. 2A, for comparison with FIG. 2C, the data formats of two adjacent information tracks are shown corresponding to their physical arrangement. As shown in FIG. 2A, the groove portion becomes a groove track 7 and the groove portion becomes a land track 8 with respect to the guide track 6 formed in a groove shape. Therefore, in the rewritable area 5 on the optical disc 1, the groove track 7 and the land track 8
Are arranged alternately. The user can track desired information (user data) by tracking the groove track 7 and the land track 8 respectively.
And the land track 8 can be recorded.

As shown in FIG. 2A, in the rewritable area 5, a sector 10 includes a first header area 11 (sector identification data PID1 and PID2) and an information area 2
Contains 0. First header area 11 and information area 20
Between the mirror mark 12 (M) and the gap region 1
3 (GAPa and GAPb) are provided. Information area 2
0 is the first dummy data area 1 as described later in detail.
5 (VFO areas: VFOa and VFOb), a first data area 17 (DATAa and DATAb), and a guard data area 18 (GDa and GDb). A buffer area 19 (BUFF) is provided between the information area 20 and the first header area 11 'of the next sector 10'.
a and BUFb) are provided. Further, the area provided in the groove track 7 is defined as a (for example, VFOa and DA
TAa), and the area provided on the land track 8 is b
(For example, VFOb and DATAb). The same applies to the following description unless otherwise specified.

As shown in FIG. 2C, the first header area 11 includes a pit row 21 (pit rows 21a and 21b) having a physically uneven shape. The width of each pit in the pit row 21 in the disk radial direction is substantially equal to the width of the guide groove 6 (groove track 7). The pit row 21
a and 21b are displaced (wobbled) from the center line of the corresponding guide groove 6 to the outer periphery or the inner periphery by about a quarter of the pitch of the guide groove 6 (groove pitch Tp).
In this embodiment, the first header area 11 is divided into a first half 11a and a second half 11b, the pit row 21a corresponding to the first half is shifted to the outer peripheral side, and the pit row 21b corresponding to the second half is shifted to the inner circumference. Has been shifted to the side.

As described above, by disposing the pit rows 21a and 21b from the center of the guide groove 6 (groove track 7), the tracking servo can be performed on either the groove track 7 or the land track 8. , The first header area 11 can be reproduced. Thus, it is not necessary to separately provide a header area dedicated to the groove track 7 and the land track 8.

If a dedicated header area is provided for each of the groove track 7 and the land track 8, in order to prevent the pit rows indicating the positions of the groove track 7 and the land track 8 from overlapping each other. A technique for forming a pit row having a width smaller than the width of the guide groove 6 is required. Such a narrow pit row can be cut by using a beam different from the beam for cutting the guide groove 6, but it is difficult to keep the positional accuracy of the two beams constant.

According to this embodiment, the cutting beam for forming the guide groove 6 is wobbled from the center of the guide groove 6 (groove track 7) to the left and right by using an AO modulator or the like, so that another cutting beam is formed. The first header area 11 (pit row 21) can be formed easily and with high precision on the optical disk 1 without the necessity of providing.

The mirror mark 12 provided after the header area 11 is used to determine which of the groove track 7 and the land track 8 is being tracked.

Gap region 13 (13a and 13b)
In order to prevent the start end 14 of the information area 20 from overlapping the mirror mark 12 or the first header area 11 even when there is a rotational jitter of the optical disc 1,
3a) and the area provided on the land track (13b).

The information area 20 is an area for recording data desired by the user. As described above, the first dummy data area 15 (VFOa and VFOb), the first data area 17 (DATAa and DATAb), 2 and a guard data area 18 (GDa and GDb) (FIG. 2).
(A)). In the information area 20, information is recorded by irradiating the recording film formed on the optical disc 1 with a laser beam to change the optical characteristics (reflectance) of the recording film. For example, by changing a crystalline recording film to an amorphous state, a recording mark having a different reflectance from other portions can be formed. As shown in FIG. 2C, the groove track 7 has a recording mark train 22a.
Are formed, and the land track 8 has a recording mark row 22b.
Is formed.

The first dummy data area 15 includes, for example,
PLL in a processing circuit for a reproduction signal from the optical disc 1
This is a VFO area for recording a specific pattern in order to operate the pull-in quickly and stably. Dummy data area 15
, A specific pattern (a specific bit length) of a modulation code used for modulating data is continuously recorded. Desired user data including an error correction code and the like is recorded in the first data area 17. The guard data area 18 is arranged at the end of the first data area 17 to ensure the stability of the reproduction signal processing circuit.

The buffer area 19 is an area in which no data is recorded. Similarly to the gap area 13, even when there is a rotational jitter of the optical disk 1, the end of the information area 20 ends at the header area of the next sector 10 '. 11 'is provided so as not to overlap.

In the rewritable area 5, data is recorded on the groove track 7 and the land track 8 according to the data format described above.

Next, the data format in the read-only areas 2 and 3 will be described with reference to FIGS. 2B and 2D. FIG. 2B shows an example of a data format in each sector 10 of the track 9 in the read-only area 2 or 3, and FIG. 2D schematically shows a physical shape of the track by a corresponding pit string.

In the read-only areas 2 and 3, the track 9 is recorded by a pre-recorded pit string (pre-pit).
Is formed. As shown in FIG. 2D, the pit strings in the read-only areas 2 and 3 are formed according to the same physical format in any data area.
That is, the pit row 29 has a radial width (pit width) of the optical disk 1 smaller than the width (groove width) of the guide groove 6 (groove track 7) formed in the rewritable area 5, and is subjected to tracking servo. All pits are arranged almost on the center line of the track.

In the read-only areas 2 and 3 as well, in the same manner as in the rewritable area 5, the track is divided into a plurality of sectors 30 and recorded, whereby the position of necessary information data is managed and the data retrieval is performed at high speed. It can be so. 1
It is preferable from the viewpoint of practical use of information recording / reproduction that unification of sector management in the read-only areas 2 and 3 and the rewritable area 5 existing on one optical disc and unification of processing of sector search and the like can be achieved. Therefore, in this embodiment, the length of the sector in the read-only areas 2 and 3, the length of the header area,
By making the length of the data area recorded in each sector equal to the length of the sector in the rewritable area 5, the length of the header area, and the length of the data area recorded in each sector, The data format is matched with the data format of the rewritable area.

Hereinafter, a specific data format of the reproduction-only areas 2 and 3 will be described. As shown in FIG. 2B, in the read-only areas 2 and 3, sectors 30
Is the second header area 31 (sector identification data PID1
And PID2) and a second data area 37. A second dummy data area 35 (VFO1) is provided between the second header area 31 and the second data area 37. In addition, a third dummy data area 38 (VFO2) is provided between the second data area 37 and the second header area 31 'of the next sector 30'.

As shown in FIG. 2D, the uneven pit rows formed in the second header area 31 are shifted inward and outward like the first header area of the rewritable area 5. Instead, they are arranged substantially on the center line of the track 9 (pit train 29) on which tracking servo is performed. Furthermore,
Compared with the width of the pit row 21 in the rewritable area 5 being substantially equal to the groove width, the width of the pit row 29 (pit width in the radial direction of the optical disc) in the read-only areas 2 and 3 is formed smaller than the groove width. Is done.

Also, in the second data area 37,
Similarly, a pit row having a concave and convex shape is arranged on the optical disk 1 substantially on the center line of a track 9 to be tracked and servoed according to data to be recorded.

Here, as can be seen from FIGS. 2A and 2B, the first header area 11 in the rewritable area 5 and the second header area 31 in the reproduction-only areas 2 and 3 are different from each other. , Its data capacity, data format (signal arrangement), and modulation code are the same.

Further, the first data area 17 in the rewritable area 5 and the second data area 37 in the read-only areas 2 and 3 have the same data capacity, data format (signal arrangement), and modulation code. It is.

As shown in FIGS. 2A and 2B, the start end (start timing) 16 of the first data area 17 in the rewritable area 5 and the second data area in the read-only areas 2 and 3 37 is matched with the start end (start timing) 36.

As described above, the first and second header areas 11 in the rewritable area 5 and the read-only areas 2 and 3 are used.
, 31 and the first and second data areas 17 and 37 have exactly the same format (signal arrangement), so that the circuit scale of the reproduction signal processing circuit can be reduced and shared as described later. Becomes

In the second dummy data area 35, if no pit row is formed between the second header area 31 and the second data area 37, the tracking error signal is interrupted and the tracking servo becomes unstable. It is provided to prevent the situation. As the data of the second dummy data area 35, for example, a specific data pattern of the same modulation code as that of the first dummy data area 15 (VFO area) in the rewritable area 5 is arranged. As a result, the PLL pull-in of the reproducing circuit can be operated quickly and stably. However, in order to stabilize the tracking servo, random data or arbitrary data may be arranged.

Similarly to the second dummy data area 35, the third dummy data area 38 is arranged to prevent the tracking error signal from being interrupted and the tracking servo from becoming unstable.

As described above, in the read-only areas 2 and 3, both the pit row of the second header area 31 and the pit row of the second data area 37 are substantially on the center line of the track 9 to be subjected to tracking servo. Are arranged. Further, between the second header area 31 of the sector 30 and the second data area 37, and the second data area 3 of the sector 30
7 and the second header area 31 'of the next sector 30' are filled with second and third dummy data areas 35 and 38, respectively. Accordingly, as shown in FIG. 2D, the physical arrangement of the pit rows 29 is uniform throughout the tracks in all of the read-only areas 2 and 3.

As described above, according to the format of the optical disc 1 according to the present embodiment, the groove tracks 7
The first header area 11 can be reproduced regardless of which of the track track and the land track 8 is tracked, and there is no need to separately provide a dedicated header area for the groove track 7 and the land track 8.

Also, the first header area 11 can be easily and accurately formed on the optical disc 1 by wobbling the cutting beam forming the guide groove 6 (groove track 7) from the track center to the left and right. Since it is possible, there is no need to separately provide a dedicated cutting light source for forming the first header region. Therefore, the pre-format formation of the rewritable area 5 of the optical disc 1 according to the present embodiment can be easily realized with a single cutting light source,
The circuit scale of the recording / reproducing device can be reduced.

FIG. 3 is a block diagram schematically showing a configuration of a reproduction signal processing section of the optical disk recording / reproducing apparatus 100 for recording / reproducing the optical disk 1 according to the present embodiment having the above data format. As shown in FIG. 3, the reproduction signal processing unit of the optical disc recording / reproducing apparatus 100 includes a two-divided photodetector 110, an addition operational amplifier 111,
Differential operational amplifier 112, switch circuit 113, binarization circuit 114, PLL (Phase-Locked Loop) 115, PI
It has a D reproduction circuit 116, a timing generation circuit 117, a demodulator 118, and an envelope detection circuit 120.

The split photodetector 110 (110a and 11a)
0b) is included in an optical head (not shown), and includes groove tracks 7 and land tracks 8 (recording marks 22 and pit rows 21) of the rewritable area 5 on the optical disc 1,
And the track 9 of the read-only areas 2 and 3 (pit row 2
The reflected light from 9) is received and converted into a reproduced signal.

The operational amplifier 111 includes the two-divided photodetector 11
0 to generate a sum signal S1 of two detection signals obtained from the two portions 110a and 110b.
Output to The operational amplifier 112 generates a difference signal S2 between the two detection signals, and outputs the difference signal S2 to the switch circuit 113 and the envelope detection circuit 120.

The switch circuit 113 switches between the sum signal S1 and the difference signal S2 and inputs the binarization circuit 114. The envelope detection circuit 120 detects the envelope of the difference signal S2, and when the difference signal S2 has an amplitude equal to or greater than a certain threshold, outputs the control signal S3 to the switch circuit 113 to switch the switch circuit 113.
The difference signal S2 is output as the output signal S4.

In the case of the data formats shown in FIGS. 2A to 2D, the output of the difference signal S2 is obtained only in the first header area of the rewritable area 5, as will be described later. Becomes high level only when the first header area 11 in the rewritable area 5 is detected (FIG. 2E). Therefore,
Only in the first header area 11, the output signal S4 from the switch circuit 113 becomes the difference signal S2. In all areas of the information area 20 and the read-only areas 2 and 3 in the rewritable area 5, the output S4 from the switch circuit 113 becomes the sum signal S1.

The output signal S4 of the switch circuit (sum signal S1
Alternatively, the difference signal S2) is binarized by the binarization circuit 114. The binarization circuit 114 binarizes the signal S4 according to, for example, a threshold value set for each of the sum signal S1 and the difference signal S2, and outputs a digital signal S5 to the PLL 115.

The PLL 115 extracts a reproduction clock from the digital signal S5 and outputs it to the PID reproduction circuit 116 which reproduces a sector identification signal from each header area. The timing generation circuit 117 uses the sector identification signal read by the PID reproduction circuit 116 to start reading the data areas 17 and 37 in which the user data is recorded (the recording data start end 16 in FIG. ) Is determined and the demodulator 118 is activated by the control signal S6. Demodulator 118 demodulates and outputs the user data.

Next, a description will be given of a signal waveform until binarization is performed when an information track recorded in the rewritable area 5 (that is, user data is already recorded in the information area 20) is reproduced. The output waveform of the sum signal S1 in the rewritable area 5 is shown in FIG.
FIG. 2 (f) shows the output waveform of FIG.

As shown in FIG. 2G, the output of the sum signal S 1 in the rewritable area 5 is in the first header area 11.
Is smaller than the predetermined threshold value 40 for binarization, so that the binarization circuit 114 does not detect the binarization. The reason is that the first header area 1
1 is slightly shifted from the center of the information track toward the outer circumference (11a) or the inner circumference (11b), so that light (beam from the optical head) is generated by the pit rows 21a and 21b.
Are diffracted, and the light reception of the photodetector 110 decreases.

On the other hand, in the information area 20 where data is recorded, since the recording mark 22 is formed at the center of the information track, the amplitude 42 of the portion corresponding to the information area 20 of the sum signal S1 is binarized. Exceeds threshold value 40. Therefore, binarization is detected by the binarization circuit 114, and a reproduced signal is obtained.

FIG. 2 (f) shows the output of the difference signal S2 in the rewritable area 5. In the area 11a of the first header area 11 of the rewritable area 5, the pit row 21a is shifted to the outer peripheral side.
The reflected light is diffracted more to the outer peripheral portion 110a of 0. Accordingly, as shown in FIG. 2F, the difference signal S2 output from the two-segment photodetector 110 has an amplitude 51a exceeding the positive threshold 50a for binarization. Therefore, 2
The binarization is detected by the binarization circuit 114, and a reproduced signal is obtained.

On the other hand, in the area 11 b of the first header area 11, the pit row 21 b is shifted toward the inner circumference side, so that more reflected light is diffracted to the inner circumference side portion 110 b of the two-divided photodetector 110. Is done. Therefore, the split photodetector 11
As shown in FIG. 2 (f), the difference signal S2 output from 0 has an amplitude 51b exceeding a negative threshold value 50b for binarization. Therefore, a binarized signal is detected by the binarization circuit 114 to obtain a reproduced signal.

However, in the information area 20 in the rewritable area 5, since the recording mark row 22 is arranged at the center of the information track, the two-divided photodetector 11
0, the light receiving amounts of the outer peripheral portion 110a and the inner peripheral portion 110b become substantially equal. Therefore, as shown in FIG. 2 (f), the amplitude 52 of the difference signal S2 becomes very small and does not reach the threshold value 51a (51b) for binarization. Play-only area 2
Similarly, the pit row 29 is arranged at the center of the track 9 in the cases of and, so that the light receiving amounts of the outer peripheral portion 110a and the inner peripheral portion 110b of the two-divided photodetector 110 become substantially equal, and the difference signal S2 is substantially Is not output to Therefore, in areas other than the first header area 11, the difference signal S2 is not binarized and no reproduced signal is obtained.

Next, FIG. 2H shows the output waveform of the sum signal S1 in the read-only areas 2 and 3. Since the pit strings 29 recorded in the read-only areas 2 and 3 are arranged on the center line of the track 9 to be subjected to tracking servo, the sum signal S1 is, as shown in FIG.
It has an amplitude 43 sufficient for binarization detection. Therefore, the second header area 31 and the second data area 37 are not distinguished,
All areas can be binarized by the output of the sum signal S1.
Therefore, there is no need to switch the switch circuit 113 in the read-only areas 2 and 3.

As described above, according to the data format of the optical disk 1 according to the present embodiment,
In the configuration of the reproduction signal processing unit of the optical disc recording / reproducing apparatus 100 for reproducing information from an optical disk, it is not necessary to separately construct a reproduction signal processing circuit for a rewritable area and a reproduction-only area unlike the related art. Therefore, a common signal processing unit can be used, and the circuit scale of the optical disk recording / reproducing apparatus can be reduced, and a highly reliable reproduced signal processing circuit can be realized with a simpler circuit configuration.

(Embodiment 2) FIGS. 4A to 4H are views for explaining the data format of an optical disk according to Embodiment 2 of the present invention. Also in the present embodiment, the basic configuration of the optical disc is the same as the configuration of the optical disc 1 according to the first embodiment, and the same components are denoted by the same reference numerals and detailed description thereof will be omitted. Also in this embodiment, the track of one rotation of the optical disk is divided into a plurality of sectors.
At the head of each sector, a header area including sector identification data indicating address information of the sector is provided. In the present embodiment, a description will be given focusing on the configuration of the data format of the read-only area.

FIG. 4A shows an example of a data format in each sector 10 of the rewritable area 5.
(C) shows the physical shape of the corresponding information track. As shown in FIG. 4C, the groove portion becomes a groove track 7 and the groove portion becomes a land track 8 with respect to the guide track 6 formed in a groove shape. Therefore, in the rewritable area 5 on the optical disk, the groove track 7
And land tracks 8 are alternately arranged. The user
By tracking the groove track 7 and the land track 8 respectively, desired information (user data)
Can be recorded on both the groove track 7 and the land track 8.

As shown in FIG. 4A, in this embodiment, the groove track 7 and the land track 8 are
It is shown as information track 6 '. In the rewritable area 5, the sector 10 has a first header area 11 at the beginning. The first header area 11 has a first half 11a (sector identification data PID1) and a second half 1
1b (sector identification data PID2), and pit rows 21a and 21b having physically uneven shapes are formed corresponding to the first half 11a and the second half 11b (FIG. 4).
(C)).

As shown in FIG. 4C, the pit train 2
The width in the disk radial direction of each pit of 1a and 21b is:
It is substantially equal to the width of the guide groove 6 (groove track 7). In addition, the pit row 21 is located on the outer circumferential or inner circumferential side from the center line of the corresponding guide groove 6 by about 1/4 of the pitch (groove pitch Tp) of the guide groove 6 (that is, in the opposite direction). It is staggered (wobbled). In this embodiment, the pit row 21a is shifted to the inner peripheral side, and the pit row 2
1b is shifted to the outer peripheral side.

As described above, by disposing the pit rows 21a and 21b from the center of the guide groove 6 (groove track 7), it is possible to perform tracking servo for either the groove track 7 or the land track 8. , The first header area 11 can be reproduced. Thus, it is not necessary to separately provide a header area dedicated to the groove track 7 and the land track 8.

As shown in FIG. 4A, a mirror area 12 (M) is provided after the first header area 11. The mirror region 12 is a flat portion where no groove or pit is formed, and is used, for example, to determine the offset of the tracking servo.

Next to the mirror area 12, the gap area 1
3 (GAP) is provided. Gap region 13 (GA
P) indicates that even when there is a rotational jitter of the optical disc 1,
This is an area provided on the information track 6 ′ so that the starting end 24 of the information area 20 does not overlap with the mirror area 12 or the first header area 11.

The information area 20 is an area in which information and data are recorded, and includes a first guard data area 23 (GD
1), a first dummy data area 15 (VFO), a first data area 17 (DATA), and a second guard data area 18 (GD2). The information area 20
A buffer area 19 (BUF) is provided between the first sector area 11 'and the first header area 11' of the next sector 10 '.

The first guard data area 23 is provided for ensuring the stability of the reproduction signal processing circuit. The first dummy data area 15 (VFO) is a VFO area provided for quickly and stably operating the pull-in of the PLL in the reproduction signal processing circuit, and includes a specific pattern (specific bit) of a modulation code used for data modulation. Is recorded continuously. Desired user data including an error correction code and the like is recorded in the first data area 17. The second guard data area 18 is disposed at the end of the first data area 17 to ensure the stability of the reproduction signal processing circuit. The buffer area 19 is an area in which no data is recorded. Similarly to the gap area 13, even when there is rotational jitter of the optical disc 1, the end of the information area 20 is overlapped by the header area 11 'of the next sector 10'. It is provided so that it does not become.

In the information area 20, information is recorded by irradiating the recording film formed on the optical disc 1 with a laser beam to change the optical characteristics (reflectance) of the recording film. For example, by changing a crystalline recording film to an amorphous state, a recording mark having a different reflectance from other portions can be formed. As shown in FIG. 4C, the recording track 22
a is formed, and the land track 8 has the recording mark train 22
b is formed.

As described above, in each area of the rewritable area 5, the groove track 7 and the land track 8 are formed according to the above data format, and data is recorded.

Next, the data format in the read-only areas 2 and 3 will be described with reference to FIGS. 4B and 4D. In this embodiment, as in the first embodiment, the data format of the read-only area is matched with the data format of the rewritable area. FIG.
4B shows an example of a data format in each sector 30 of the track 9 in the read-only area 2 or 3, and FIG. 4D schematically shows a physical shape of the track by a corresponding pit row.

In the read-only areas 2 and 3, the track 9 is recorded by a pre-recorded pit string (pre-pit).
Is formed. As shown in FIG. 4D, the pit strings in the read-only areas 2 and 3 are the same as in the first embodiment.
Each data area is formed according to the same physical format. That is, the pit row 29 is
Is smaller than the width (groove width) of the guide groove 6 (groove track 7) formed in the rewritable area 5, and all the pits are substantially on the center line of the track to be subjected to tracking servo. Are arranged.

As shown in FIG. 4B, in the read-only areas 2 and 3, the sector 30 includes a second header area 31 (sector identification data PID1 and PID2) and a second data area 37 (DATA). Contains. Second
Between the header area 31 and the second data area 37
Dummy data area 33 (DMY1) is provided. Further, a third dummy data area 34 (DMY2) is provided between the second data area 37 and the second header area 31 'of the next sector 30'.

The sector identification data PID1 and PID2 in the second header area 31 correspond to the second header area 31.
In order to make the length of the first header area 11 substantially equal to the length of the first header area 11, the length of the first and second half sections of the second header area 31 is adjusted in accordance with the sector identification data PID 1 and PID 2 in the first header area 11. Record repeatedly. However,
The uneven pit row formed in the second header area is
Pit trains 21a and 21 formed in the first header area
The tracks 9 are arranged on the center line of the track 9 on which tracking servo is performed, without being shifted to the inner and outer circumferences as shown in FIG.

The second data area 37 includes one sector 3
0 is made equal to the information amount recorded in one sector 10 in the rewritable area 5 and the format such as an error correction code to be added is made the same, so that the first data area 17 and the data The lengths of the regions are made substantially the same.

In general, recording by embossing in a read-only area can be performed with high accuracy when manufacturing a disc. In addition, since data is simply reproduced in the reproduction-only area, it is not necessary to cope with data rewriting by the user. Therefore, in the reproduction-only area, the gap area 13, the first guard data area 23, the second guard data area 18, and the buffer area 19 provided in the rewritable area are unnecessary. Therefore, if priority is given to the recording capacity of the optical disk, these areas should be deleted. However, if these areas are deleted, the data format differs between the read-only area and the rewritable area. Therefore, as described in the conventional example, the timing generation circuit and the demodulation circuit are rewritten as those for the read-only area. It is necessary to prepare two systems for the available area and switch between these systems for use. Also, to match playback timing,
The gap area 13, the first guard data area 23, the second
If the areas corresponding to the guard data area 18 and the buffer area 19 are provided and no pit row is formed in these areas, the tracking error signal is interrupted in these areas, and the tracking servo in the read-only area becomes unstable. Would.

Therefore, in the present embodiment, the second dummy data area 33 is arranged in a portion between the header area 31 and the data area 37 in each sector 30, and the data area 3
7 between the header area 31 'of the next sector 30' and the third sector 30 '.
Are arranged.

The data to be recorded in the second and third dummy data areas 33 and 34 is, for example, a modulation code used for data modulation, similar to the first dummy data area 15 (VFO) in the rewritable area. (A specific pulse width and a specific bit length pattern corresponding to a pulse interval) can be continuously recorded. By using such a specific pattern, the PLL pull-in of the reproduction signal processing circuit can be quickly and stably operated even in the reproduction-only area.

Further, a mirror area may be provided between the header area 31 and the second dummy area 33 in the same manner as the rewritable area.

The reproduction of the optical disk according to the present embodiment is exactly the same as that of the optical disk recording / reproducing apparatus 100 described in the first embodiment with reference to FIG.
In this case, the envelope detection signal, the difference signal in the rewritable area, the sum signal in the rewritable area, and the sum signal in the reproduction-only area are as shown in FIGS. 4 (e) to 4 (h), respectively.

As described above, according to the present embodiment, the main portion of the data format is arranged substantially the same, for example, the sector length is made the same in the rewritable area and the read-only area. It is possible to unify the management of the sector in the area and the rewritable area, and to unify processing such as sector search. Therefore, by sharing the reproduction signal processing circuit between the rewritable area and the reproduction-only area,
The circuit scale can be reduced.

In this embodiment, FIGS. 4A and 4
In (b), the data area 17 of the rewritable area and the data area 37 of the reproduction-only area are displayed so as to be arranged at the same timing. However, the present invention is not limited to this, and the lengths of these data areas are equal. Thus, even if the arrangement is shifted back and forth, unified sector management according to the present invention can be effectively performed.

(Embodiment 3) Next, a third embodiment of the present invention will be described. In this embodiment, a description will be given of a data array capable of stably performing tracking servo in reproduction of a reproduction-only area. The data format of the optical disc in this embodiment is the same as that of the optical disc described in the second embodiment, in both the rewritable area and the read-only area.

In general, there are various methods for performing tracking control along tracks on an optical disk. For example, as shown in FIG.
As a tracking servo method effective for the track formed in step 9, there is a phase difference detection method.

As described in the second embodiment, the second and third dummy data areas 33 and 34 shown in FIG. 4B have the specific pattern (specific pulse width) of the modulation code used for data modulation. , A specific bit length pattern corresponding to the pulse interval) are continuously arranged. However,
When such a specific continuous pattern is arranged on an adjacent track, there is a problem that tracking servo by the phase difference detection method becomes unstable.

Here, the reason why the tracking servo becomes unstable will be described below.

FIG. 5 is a diagram for explaining the principle of obtaining a tracking error signal by the phase difference detection method. The beam spot 57 tracks the uneven pit row 29 forming the track 9 in the read-only area. The light of the beam spot 57 is reflected by the pit row 29, and the reflected light is detected by the quadrant photodetector 58. The quadrant photodetector 58 receives the reflected light from the beam spot 57 and converts it into an electric signal. The quadrant photodetector 58 includes four division planes A, B, C, and D. The operational amplifier 59 generates the sum signal S11 of the divided plane A + C, and the operational amplifier 60 generates the divided signal B11.
The + D sum signal S12 is generated. The phase comparator 61
The tracking error signal S13 is generated by comparing the phases of the two sum signals S11 and S12.

When the beam spot 57 deviates upward from the center line of the track 9, the reflected light is diffracted at the edge of the pit 29, so that the phase of the sum signal S11 of the division plane A + C advances. On the other hand, when the beam spot 57 deviates below the center line, the phase of the sum signal S12 of the division plane B + D advances. Accordingly, the phase difference between the two sum signals S11 and S12 is detected by the phase comparator 61 and converted into a voltage signal, thereby obtaining a tracking error signal S13 representing the deviation of the beam spot 57 from the track center.

FIGS. 6 and 7 show tracking error signals obtained by the above-described phase difference detection method when the beam spot 57 deviates from the track center. FIG. 6 shows a target track 9a (pit train 29a) to be tracked and an adjacent track 9b (pit train 29b).
7 shows output waveforms of the sum signals S11 and S12 when the beam spot 57 deviates from the target track 9a when exactly the same data pattern is recorded. FIG.
As shown in the figure, the trajectory 64 of the beam spot 57 is
It is out of the destination track 9a.

In this case, the light of the beam spot 57 is generated by the upper edge of the pit row 29a of the target track 9a.
Light is diffracted to the four-divided surface A + B side of the four-divided photodetector 58. However, since the adjacent track 9b has the pit row 29b of exactly the same pattern, the light of the beam spot 57 simultaneously emits the pit row 29b of the adjacent track 9b.
The light is diffracted by the lower edge b into the quadrant C + D. As a result, as shown in FIG.
And the sum signal S12 of the quadrant B + D are
The output of the tracking error signal S13 becomes zero even though the phase difference disappears and the beam spot 57 deviates from the target track 9a.

As described above, the adjacent tracks 9a and 9b
In the case where pit rows having exactly the same pattern are formed, no tracking error signal S13 is generated and the tracking servo becomes unstable even if the track goes off.

FIG. 7 is an output waveform diagram of the sum signals S11 and S12 by the phase difference detection method when pits having a data sequence different from that of the target track 9a are arranged on the track 9b adjacent to the target track 9a. . It is assumed that the beam spot 57 tracks a locus 64 deviating from the target track 9a as in FIG.

In this case, as in the case of FIG. 6, the light of the beam spot 57 is emitted from the pit train 29 of the target track 9a.
The light is diffracted toward the four-divided surface A + B of the four-divided photodetector 58 by the upper edge of a. At the same time, beam spot 5
The light 7 is diffracted by the lower edge of the pit row 29b of the adjacent track 9b toward the quadrant C + D. But,
Since the pit arrangement pattern is different between the target track 9a and the adjacent track 9b, in the portions 65 and 66 where the pit edges of the two adjacent tracks coincide, FIG.
As in the case of the example, the outputs of the two sum signals S11 and S12 coincide with each other, and no phase difference occurs. A phase difference occurs in S12.

If the pit arrangement of the target track 9a and the pit arrangement of the adjacent track 9b are not correlated with each other and are random, as shown in parts 65 and 66 in FIG. Also occur at random, so that the frequency of occurrence of the coincidence portion of the edge decreases. In the frequency domain used for the tracking servo, even if a portion where the phase difference cannot be obtained randomly occurs, there is almost no problem in generating the tracking error signal S13.

However, as shown in FIG. 6, for example, when the phase difference cannot be obtained over the entire area of the second and third dummy data areas 33 and 34, the tracking error signal S13 in the case of the off-track occurs. Cannot be obtained sufficiently, and the tracking servo control becomes unstable.

The data format in the second dummy data area 33 and the third dummy data area 34 effective for preventing the above-described disturbance of the tracking servo will be described.

FIG. 8A shows the second dummy data area 3
A format example in which random data 73 and 74 generated in the M sequence are arranged in the third and third dummy data areas 34 is shown. If the initial value of the random data generated in the M-sequence is changed between at least two adjacent tracks, the correlation of the pit arrangement patterns on the adjacent tracks is lost, so that the coincidence of the pit edge positions between the adjacent tracks is random. Be transformed into Therefore, even if tracking servo is performed by the phase error detection method, relatively stable control can be performed.

FIG. 8B shows the second dummy data area 3
3 shows M-sequence random data 73 similar to that shown in FIG.
Next, a format example in which a specific pattern of a modulation code used for data modulation similar to that of the VFO area 15 (FIG. 4A) in a partially rewritable area is arranged is shown.

As shown in FIG. 8B, a part of the second half of the second dummy data area 33 is replaced with a VFO area 75 (VF
By setting O1), there is an effect of stabilizing the pull-in of the PLL of the reproduction signal processing circuit into the data area 37 arranged subsequently. Also, the VFO area 75
Does not generate the tracking error signal S13, but VFO
Since the area 75 is a part of the dummy data area, the tracking servo can be stably applied before and after the area 75, so that there is no practical problem.

FIGS. 8C and 8D show format examples in which data synchronization sequences 76 and 77 capable of specifying the timing of the start point of the data area 37 are arranged in the second dummy data area 33, respectively. FIG. 8C shows an even-numbered track, and FIG. 8D shows an odd-numbered track.

As described above, in order to secure a stable tracking servo in the phase error detection method, it is necessary to arrange different data sequences between adjacent tracks. Therefore, the data synchronization sequence 7 differs between the even track (FIG. 8 (c)) and the odd track (FIG. 8 (d)).
6 and 77 are arranged.

As shown in FIG. 8C, a data synchronization sequence 76 which counts up by the final value FF (HEX) is arranged on the even track. In this way, the timing up to the start point of the data area 37 can be detected in real time in the second dummy data area 33 due to the regularity (count-up) of the data synchronization sequence 76. Can be reliably recognized.

As shown in FIG. 8D, a data synchronization sequence 77 that counts down at the final value 00 (HEX) is arranged on the odd track. As in the case of the even track, the timing up to the start point of the data area 37 can be detected in real time in the second dummy data area 33 by the regularity (countdown) of the data synchronization sequence 77.

As described above, in the format examples shown in FIGS. 8 (c) and 8 (d), a different data synchronization sequence is arranged in each second dummy data area 33 in an adjacent track, so that tracking servo is performed. And the effect of reliably detecting the start point of the data area 37 can be expected.

As described above, according to the present embodiment, by randomizing the data arrangement of the second dummy data area 33 between adjacent tracks, the tracking servo in the read-only area uses the phase error detection method. A relatively stable servo is also possible. Further, by arranging different data synchronization sequences from the adjacent tracks in the second dummy data area 33, the tracking servo can be stabilized and the start point of the data area 37 can be reliably detected.

Although the data arrangement of the second dummy data area 33 has been described above, a data arrangement suitable for the tracking servo can be similarly applied to the third dummy data area 34. In the above, the reproduction operation (tracking servo) in the reproduction-only area has been described. However, the reproduction operation in the rewritable area is the same as that described in the first embodiment by the optical disk recording / reproducing apparatus 100 (FIG. 3).

(Embodiment 4) In Embodiment 3 described above, a pattern of data (code) recorded in the dummy data area can be directly generated at the time of reproduction. In the present embodiment, a method of using a modulation code to reduce the correlation between dummy data recorded on adjacent tracks will be described.

First, one value is determined in advance as data to be recorded in the dummy data area. Then, by scrambling this value, data with little correlation is generated. For example, hexadecimal (FF), (00)
For example, since all bits are 0 or 1, data can be easily generated based on this value. Scramble is realized by generating random data such as an M-sequence from a certain initial value, and taking an exclusive OR of this and data to be recorded. A method of generating scrambled data will be described in detail in a later embodiment.

If the data to be recorded is the same and the initial value is also the same, the data after scrambling will be the same. However, even if the data to be recorded is the same, the correlation of the scrambled data can be reduced by changing the initial value. It is difficult to change the initial value in all the sectors because a large number of initial values must be held. However, in order to reduce the correlation of the dummy data area between adjacent tracks, it is sufficient that the initial value differs between adjacent sectors, and the same data may be used for one round of the track. When the number of sectors included in one round of the track changes depending on the radial position on the optical disk, the number of consecutive sectors having the same initial value only needs to be equal to or less than the minimum number of sectors included in one round of the track. The number of consecutive sectors having the same initial value is M, and the type of the initial value is N. It is convenient to create such values of M and N from the address information of the sector included in the sector identification data.

For example, as address information of a sector, 3
Using byte data, it is possible to represent about 16.77 million sectors. If the values of M and N are powers of 2, it is easy to generate scrambled data. In this embodiment, a case where M = 16 and N = 16 will be described. The N initial values can be obtained, for example, as follows. First, the address information data of the sector identification data is represented in binary, and 4-bit data from the 5th bit to the 8th bit counted from the least significant bit is used. By setting the initial values corresponding to the 4-bit data, N = 16 types of initial values can be represented. It is also assumed that the initial value is updated every M = 16 sectors, and one sector of a track is formed by 256 sectors.

Therefore, since 16 consecutive sectors have the same initial value, it is possible to guarantee that the initial value of scrambling differs between adjacent sectors, from 16 sectors to 256 sectors in one track. The data to be recorded is scrambled by using these initial values, modulated by a recording code, and recorded in a dummy data area.

As described above, by scrambling the same data using different initial values between adjacent tracks (corresponding sectors), different data sequences are stored in the dummy data area between adjacent tracks. Can be arranged.

Therefore, according to the present embodiment, since the data arrangement of the dummy data area between adjacent tracks can be efficiently randomized, it is relatively stable even if tracking servo is performed using the phase error detection method in the read-only area. Tracking control can be realized.

(Embodiment 5) Next, a third embodiment of the present invention will be described. In the present embodiment, a data arrangement of a rewritable area or a read-only area that enables efficient sector management will be described.

In the above-described embodiment, as described with reference to FIGS. 4A and 4B, for example, data to be recorded on the optical disk includes the data area 17 (rewritable area) of each sector or the rewritable area. It is divided for each data capacity corresponding to the data area 37 (reproduction only area). As mentioned above,
An error correction code is added to the recording data of each sector.
As this error correction code, there is a method of performing error correction coding on a set of a plurality of sectors instead of a correction code method completed within each sector. Such a group of a plurality of sectors is called an ECC block. That is, the ECC block is a unit of error correction coding. One EC with k sectors
When a C block is configured (for example, a set of k = 16 sectors), even if an error having a length of about one sector occurs, the error can be corrected. When such an error correction code is used, the number of sectors recorded in the rewritable area and the read-only area is both an integral multiple of the ECC block. That is, in each area, an integral multiple of k sectors is recorded.

On the other hand, in order to efficiently manage sectors on the optical disc, it is desirable to manage the sectors included in each area in the rewritable area and the read-only area on a track basis. However, the number of sectors for one round of a track is not always an integral multiple of the number of sectors included in one ECC block. Therefore, multiple ECs
When the C block is recorded, the data does not always end at a position where the cut of one track is good.
In many cases, data ends in the middle of one round of the track. In the rewritable area, even if an unrecorded sector of data remains, the tracking control can be performed because the guide track of the groove or the land is formed. However, in the read-only area, if there is an unrecorded sector, the formed pit row is interrupted.
Tracking control becomes unstable.

For this reason, in this embodiment, dummy data is recorded in the remaining sector where recording data has been completed in order to fill one round of the track with data so that sector management can be performed in track units. As the dummy data to be recorded, for example, the VFO area 15 in the rewritable area
A specific pattern (a specific pulse width and a pulse interval) of the modulation code similar to the above can be continuously arranged. By setting the dummy data in such a pattern, the PLL of the reproduction signal processing circuit can be operated stably even in a sector where no user data is recorded.

As in the case of the second dummy data area described in the third embodiment, it is also possible to record M-sequence random data, a data synchronization sequence pattern, or data scrambled in the fourth embodiment. . FIG.
1 shows an optical disc 1 'according to the present embodiment. As shown in FIG. 9, the read-only area 3 and the rewritable area 5 on the inner peripheral portion are provided.
Is connected to the sector 71 of the read-only area 3.
Is recorded with dummy data. Similarly, dummy data is also recorded in the sector 72 of the read-only area 2 at the connection between the read-only area 2 and the rewritable area 5 on the outer peripheral portion.

As described above, for example, the error correction block E
When data is recorded in a predetermined recording unit, such as CC, the rewritable area and the connection part are always tracked by supplementing the dummy data recorded sectors to the unrecorded remaining read-only area sectors. You can start from the beginning. As a result, sector management on the optical disk can be efficiently performed.

(Embodiment 6) In a sixth embodiment of the present invention, a specific example of the data format in the sector 10 of the rewritable area and the sector 30 of the read-only area will be described.

FIGS. 10A and 10B show the layout of the sector 10 in the rewritable exclusive area.
(A) and FIG. 11 (b) show sector 3 in the read-only area.
0 shows the layout. First, generation of data to be recorded in the first data area 17 of the sector 10 and the second data area 37 of the sector 30 will be described.

In both the sectors 10 and 30, the data amount recorded in one sector is assumed to be 2048B (B represents bytes, the same applies hereinafter). In addition, 4B of data ID indicating the data area number (sector address), 2B of IED for error detection of the data ID, and 6B of RSV as a backup, and 4B ED to perform error detection for all of them.
C is added. These are collectively referred to as a first data unit. The data length of the first data unit is 2048
+ 4 + 2 + 6 + 4 = 2064 (B).

The information data section (2048B) is scrambled. The scrambling method is the same as that used for the dummy data area shown in the fourth embodiment, and is performed as follows.

First, a shift register is configured to generate so-called M-series data, and an initial value is set in the shift register. The initial value in the shift register is sequentially shifted in synchronization with the data to generate pseudo-random data. By performing an exclusive OR operation on the pseudo-random data and the information data to be recorded for each bit, scrambling is realized.

As described above, the information data is 2048B, and the data amount is 2 11. Therefore, a primitive polynomial of 2 11 or more is required as the M sequence. In the primitive polynomial constituting the M-sequence, in the 3 to 5 terms having 11 or more terms in the primitive polynomial, the next minimum order is the 15th power. As an example, a primitive trinomial (X ¹⁵ + X ⁴ +1) having a term of 2 15 will be used. FIG. 12 shows the realization of this primitive polynomial by the shift register 150.

As shown in FIG. 12, the length of the shift register 150 is 15 bits (entries r14 to r0). The shift register 150 takes the exclusive OR of the bit of the entry r14 and the bit of the entry r10, and feeds back the result to the entry r0. A predetermined 15-bit initial value is set in the shift register 150,
Pseudo-random data can be generated by sequentially circulating according to the bit clock. And
For example, an exclusive OR of the lower 8 bits (entries r7 to r0) of the shift register 150 and the 8 bits (1B) of the information data is taken every 8 clocks, and this is repeated 2048 times. As a result, the information data of one sector is scrambled. By resetting the shift register 150 for each sector and resetting the initial value, the information data of each sector can be scrambled independently (substantially without correlation).

Here, it is assumed that the number of consecutive sectors having the same initial value is M, and the type of the initial value is N. Such M
And N can be created from the address information of the sector included in the identification data. The value of M and N is 2
It is easy to generate such scramble data if it is a power of. As an example, assume that M = 16 and N = 16.
The N initial values can be obtained, for example, as follows. First, the data of the address information of the sector identification data is expressed in binary (when the sector address is 3B, 2
4 bits from the least significant bit to the 5th to 8th bits. By setting the initial values corresponding to the 4-bit data, N = 16 types of initial values can be represented. 4 above
The correspondence between the bit value and the initial value is determined in advance, and a correspondence table or the like is used. Also, the initial value is updated every M = 16 sectors, and one cycle of the track is 256 sectors.

As described above, the first data units subjected to the scramble processing are collected for 16 sectors, and an error correction code based on the Reed-Solomon code is formed. Data units for one sector are arranged in 172B × 12 rows, and
By collecting sectors, an array of 172B × 192 rows is formed. An outer code of 16B is added to each column of this array. Next, an inner code of 10B is added to each row. As a result, a data block of 182B × 208 rows (378
56B). This is called an ECC block.

Next, interleaving is performed so that the 16B outer code is included in each sector. The data in each sector is
182B × 13 rows = 2366B.

Next, modulation is performed using the recording code. The run length after modulation was limited as a recording code (Run Length Limite
d) Use RLL code. Here, as the recording code,
Convert 8 bit data to 16 channel bits 8
/ 16 conversion code is used. This conversion is performed according to a predetermined conversion table (conversion table). For example, four types of 16-channel bit data can correspond to one 8-bit data. This type is called a state. In the above conversion table, states used for conversion of the next data are also defined in advance.

FIG. 13 shows an example of such a conversion table. For example, the first data (D _t ) is transferred to state 1 (S _t =
By performing conversion according to the table of 1), a 16-bit code sequence (Y _t ) is obtained. The next data is selected from the state ( _{St + 1} ) table specified in the previous conversion. Although a detailed control method is omitted, the DC component included in the recording code can be suppressed by controlling the selection of the state.

At this time, the shortest bit length is limited to 3 channel bits, and the longest bit length is limited to 11 channel bits. Also, a 2B synchronization code is inserted to synchronize at the time of reproduction. The synchronization code is inserted every 91B, which is half of 182B for one row. As the synchronization code, several kinds of 32-channel bit length codes having patterns that do not normally appear in the above-described 8/16 conversion code are determined in advance. Thus, data of one sector is 186B × 13 rows = 2418
B.

The above data structure is common to the rewritable area and the reproduction-only area. The 2418B data obtained in this way is stored in the first data area 17 of the sector 10 in the rewritable area as shown in FIG. 10A, or in the read-only area as shown in FIG. It is recorded in the second data area 37 of the sector 30.

As shown in FIG. 10A, in the rewritable area, following the first data area 17, 1
The B postamble area 45 (PA) is arranged. In the above 8/16 conversion code, it is necessary to provide the end of the code at the end of the recording code in order to correctly decode the data at the time of reproduction. Therefore, the first postamble area 45
Is recorded with a pattern obtained by modulating a predetermined code according to a conversion rule.

Further, in front of the first data area 17,
A pre-sync area 4 that indicates a start point of the first data area 17 and records pre-sync data for achieving byte synchronization.
4 (PS). Pre-sync data is 3B
A code having a pattern length of (48 channel bits) and a high autocorrelation is determined. For example, “0000 0100 0100 1000 0010 0001 0010 0000” represented by the NRZI code
The pattern "1000 0010 0001 0000" is used.

The VFO area 15, the first guard data area 23, the second guard data area 18, the gap area 13, the buffer area 19, and the mirror area 12 shown in FIG. VF described in (a)
O area 15 (VFO), first guard data area 23
(GD1), the second guard data area 18 (GD2),
Gap area 13 (GAP), buffer area 19 (BU
F) and a region similar to the mirror region 12 (M).
The guard data area 23, the VFO area 15, and the PS area 44 form a first dummy data area 15 '.
In FIG. 10A, the numbers below each area indicate the byte length of that area. The same applies to FIGS. 10 (b), 11 (a) and 11 (b).

As shown in FIG. 10A, the VFO area 15 is provided before the PS area 44 in the first dummy data area 15 '. The VFO area 15 is an area for recording data of a specific pattern in order to quickly and stably operate the PLL pull-in of the reproduction signal processing circuit.
It is preferable that the pull-in of the PLL include a large number of code inversions (“1” represented by the NRZI code). However, when performing high-density recording, when the modulation code has the shortest bit length, the amplitude of the reproduction signal is small and the C / N is low, making it difficult to pull in a stable clock. Therefore, a repetition pattern of four channel bits having the next shorter bit length is used. When represented by an NRZI code, the pattern becomes "... 1000 1000 ...". In order to secure the number of inversions and pull-in time required for stable clock pull-in, VF
The length of the O region 15 is 35B.

The first guard data area 23 is provided before the VFO area 15, and the second guard data area 18 is provided after the postamble area 45 (PA). As described in the fourth embodiment, in a rewritable optical disk, when recording and erasing are repeatedly performed, deterioration due to a thermal load at the start and end of the recording unit increases. The guard data area needs to have a length such that the deteriorated portion does not extend from the VFO area to the PA area.

Since the recording medium has the property of deteriorating by repeatedly recording the same data at the same location, the lengths of the first and second guard data areas 23 and 18 before and after the data area 17 are increased. By expanding and contracting, the recording position of the first data area 17 is moved. However, the total length of the first guard data area 23 and the second guard data area 18 is assumed to be constant. According to the result of the experiment, the first guard data area 23 is (15 + k)
B, (45-k) B as the second guard data area 18
, And the moving amount is preferably from k = 0 to 7B. The total length of both guard data areas is constant at 60B. The data to be recorded in the guard data area is, for example, a repetition pattern of four channel bits “... 1000 1000...” Similar to the VFO area 15.

As described above, the first guard data area 23, VFO area 15, pre-sync area 44, first data area 17, and postamble area 4 shown in FIG.
5 and the second guard data area 18 are information recording areas for recording data, and the data length is 2517B.

The gap region 13 is used for setting a laser power. In order to secure the time required for setting the power, the gap region 13 has a length of 10B. The buffer area 19 is provided with a non-recording area (time width) so that the end of the recording data does not overlap with the next sector even if the rotation of the disk motor fluctuates or the disk is eccentric. The buffer area 19 has a length of 40B. The mirror area 12 has a size of 2B in order to secure the time required for determining the offset of the tracking servo.
Is provided.

Next, the configuration of the sector 30 in the read-only area will be described with reference to FIG. FIG.
As shown in (a), the sector 30 includes a header area 90,
A second dummy data area 33, a second data area 37,
And a third dummy data area 34. As described above, the data length recorded in the second data area 37 is
24 which is the same as the data length recorded in the first data area 17
18B. Similarly to the sector 10, the 1B postamble area 47 (P
A), second pad area 85 and postamble area 8
6 (PA) are arranged.

In this embodiment, similar to the second embodiment,
The second dummy data area 33 is arranged between the header area 90 and the second data area 37, and the third dummy data area 34 is arranged between the data area 37 and the head of the next sector. The second dummy data area 33 has a 35B VFO area 84 in the same manner as the sector 10 of the rewritable area in order to ensure the reliability of the data area 37 during reproduction.
And a 3B pre-sync area 46 (PS). FIG.
1 (a), the second dummy data area 33
Further includes a 30B first pad area 82 and a postamble area 83 (PA). The third dummy data area 34 includes a postamble area 47 and a second
Are formed from the pad region 85 and the postamble region 86.

The pattern and data length of data recorded in the VFO area 84 and the pre-sync area 46 are as shown in FIG.
VFO area 15 and pre-sync area 44 shown in FIG.
And the same as Further, as described in the fourth embodiment, as data to be recorded in the second and third dummy data areas,
For the (FF) data expressed in hexadecimal, scrambling is performed using different initial values between adjacent sectors, and a data sequence modulated by the above-described 8/16 conversion code is used. The scrambling method is the same as the method performed for the data area 37. For setting the initial value, 4-bit data from the fifth bit to the eighth bit counted from the least significant bit of the PID described later is used. The initial value corresponding to the 4-bit data is the same as the initial value of the data area 37.

The 8/16 conversion coding starts from the head of each pad area, for example, from state 4 in the conversion table shown in FIG. The data series generated in this manner is divided into a first pad area 82 and a second pad area 85.
To record. The first pad area 82 corresponds to the gap area 13 and the first guard data area 23 in FIG. 10A, and the second pad area 85 corresponds to the second guard data area 18 in FIG. And the buffer area 19.

In the rewritable area, the lengths of the first and second guard data areas 23 and 18 are changed. In the read-only area, the length of the corresponding pad area is made to correspond to the average length of the first and second guard data areas 23 and 18 so that the first pad area 82 has a size of 28B.
And the second pad area 85 is 80B. After the first and second pad regions 82 and 85, 1B postamble regions 83 and 86 are arranged to terminate the modulation code.

Next, the structure of each header area in the recordable area and the read-only area will be described. Example 2
As described with reference to FIG. 4A, the header area 11 of the rewritable area is divided into the first half 11a (sector identification data PID1) and the second half 11b (sector identification data PID2), and the corresponding pits are formed. The rows 21a and 21b are arranged so as to be displaced in the radial direction from the center line of the groove track 7 (the guide groove 6) by approximately a quarter of the groove pitch. Further, the pit row 21a and the pit row 21b are arranged such that their shifts are in opposite directions. Also in this embodiment, the header area 80 is arranged similarly.

FIG. 10B shows the data format of the header area 80 of the sector 10 in the rewritable area. As shown in FIG. 10B, the header area 80
Has four sector identification data (PID). These sector identification data are PID1, PID1
2, PID3, and PID4. And, for example,
The first half PID1 and PID2 of the 64B are displaced toward the outer periphery of the disk, and the second half PID3 and PID4 of the 64B are displaced toward the inner periphery of the disk.

In each sector identification data PID, 4 B is stored in the Pid area representing the address information of the sector, 3 B is stored in the sector number, and 1 is stored in various information of the sector such as the number of the PID area.
Assign B. In the Pid3 area 213 and the Pid4 area 218 of the latter half PID3 and PID4, the address information of the sector of the groove track 7 to be displaced with respect to the center line is recorded. The Pid1 area 203 in PID1 and PID2 in the first half
And the Pid2 area 208 include the groove track 7
The address information of the sector of the land track 8 adjacent to the outer circumference of the sector is recorded.

A 2B error detection code is added to each Pid area, and these are added to the IED areas 204, 209, and 21.
4 and 219. The data in the Pid area and the IED area are modulated by the above 8/16 conversion code. This modulation is started from the state 1 from the head of each Pid area using, for example, the conversion table shown in FIG. In order to terminate the modulation code, the postamble area 2 of 1B is used.
05, 210, 215, and 220 are located after the corresponding IED area.

The Pid areas 203, 208, 21
Before 3 and 218, the starting point of each Pid area is indicated,
AM that records address marks for byte synchronization
Regions 202, 207, 212, and 217 are provided, respectively. As the address mark, a pattern that does not appear in the 8/16 conversion code, for example, a code of 3B (48 channel bits) length is selected. For example, "00" represented by an NRZI code
01 0001 0000 0000 0000 0100 0100 0100 0000 0000 00
01 0001 ". Since this pattern includes twice a pattern of 14 channel bits longer than 11 channel bits which is the longest bit length of the modulation code, erroneous detection during normal data reproduction is reduced.

At the head of each sector identification data PID, a corresponding VFO area is provided. The VFO area is an area for recording data of a specific pattern in order to quickly and stably operate the PLL pull-in of the reproducing circuit. For example, similarly to the VFO area in the second embodiment, “... 1000 1000
.. "Can be used. As described above, the header area 80 includes the first half PID1 and PID2 as one set, and the second half PID3
And PID4 as one set and displaced in the opposite direction in the radial direction. First VFO area 201 at the beginning of each set
And 211 need to be able to re-establish the bit synchronization in order to ensure the bit synchronization.
The length is made longer than the O region. Second VFO in each set
Regions 206 and 216 may be short because they only resynchronize. In this embodiment, the first VFO regions 201 and 2
11 for 36B and second VFO regions 206 and 216 for 8
B.

Therefore, each PID includes, for example, PID1
In the case of, the VFO area 201 (VFO
1) The AM area 202, the Pid area 203, the IED area 204, and the postamble area 205 are arranged, and their length is 46B. Similarly, in the case of PID2, the VFO area 206 (VFO2), the AM area 2
07, a Pid area 208, an IED area 209, and a postamble area 210 are arranged, and their length is 18B. The same applies to PID3 and PID4 in the latter half.

Next, the data arrangement in the header area of the reproduction-only area will be described with reference to FIGS. 11 (a) and 11B. As already described in the second embodiment (FIGS. 4A and 4B), the data arrangement of the header area 31 of the read-only area is matched with the data arrangement of the header area 11 of the rewritable area. In the physical arrangement, the pit row corresponding to the header area 31 was arranged inline with respect to the track 9. Also in this embodiment, the header area 9
0 is arranged in the same manner as in the second embodiment. The data arrangement and the length (bit length) in the header area 90 in the reproduction-only area are determined by the header 80 in the rewritable area.
(FIG. 10A). That is, as shown in FIG. 11A, the header area 90 is 128B, and the identification data PID is recorded four times repeatedly (PID1 to PID).
ID4). For example, as shown in FIG.
In the case of 1, the VFO area 231 (VFO
1) The AM area 232, the Pid area 233, the IED area 234, and the postamble area 235 are arranged, and their length is 46B. Similarly, in the case of PID2, the VFO area 236 (VFO2), the AM area 2
37, a Pid area 238, an IED area 239, and a postamble area 240 are arranged, and their length is 18B. The same applies to PID3 and PID4 in the latter half.

As described above, according to this embodiment, the dummy data area 33 of the adjacent track in the read-only area is provided.
Alternatively, different data series can be arranged in 34. This means that certain fixed data (for example,
FF) by using the same scrambling as the scrambling for the data recorded in the data area 37 and performing scrambling with different initial values between adjacent sectors. Such scrambled data is modulated with the same recording code as the recording code used for the data in the data area 37 to form a pad area 82 or 85.
In this case, even when the tracking servo in the read-only area uses the phase error detection method, relatively stable servo can be performed. Further, a scramble circuit and a recording / encoding circuit for creating data to be recorded in the pad areas 82 and 85 can be shared with a scramble circuit and a recording / encoding circuit for creating data to be recorded in the data area 37. Thus, the configuration of the recording signal processing circuit can be simplified, and the circuit scale can be reduced.

In this embodiment, the position of the data area 17 is moved by expanding and contracting the lengths of the first and second guard data areas 23 and 18 in the recordable area. However, the present invention is not limited to this. For example, the length of the gap region 13 and the length of the buffer region 19 may be expanded and contracted in the same manner, and may be further expanded and contracted by combining them.

(Embodiment 7) In Embodiment 6 described above, the sectors 10 and 3 in the recordable area and the read-only area are used.
The example of the data array of 0 has been described. FIG. 10 (a) and FIG.
As shown in FIG. 1A, in the recordable area, a pre-sync area 44 is provided after the VFO area 15 and before the data area 17, and in the read-only area, the VFO area 8 is provided.
4, a pre-sync area 46 is provided before the data area 37.

On the other hand, in a conventional optical disk, as shown in FIG. 23, for example, a data area 450 is arranged immediately after a VFO area 403. Data area 45
0 is the data synchronization sequence 404a, 404 corresponding to the head.
a plurality of data blocks 405 in which b,.
a, 405b,...

In the data format as described above, at the time of reproduction, first, the clock synchronization in the PLL circuit is stabilized by the VFO area 403, and then the data synchronization sequence 404a is detected. Then, the data synchronization sequence 404a
, The head of the data area 450 is recognized, and the first data block 405a is reproduced.

However, in the above configuration, if, for example, the recording film of the optical disc is damaged in the portion of the first data synchronization sequence 404a that specifies the start timing of the head data block 405a, the synchronization data to be read out There is a problem that an error occurs and the start position of the head data block 405a cannot be specified.

Further, if the start position of the head data block 405a cannot be specified, the head data block 405a
In addition, since the block number of the succeeding data block 405b cannot be specified, an error occurs in the data in the data area 450 of the entire sector, and reading becomes impossible.

However, as described above, according to the data format of the sixth embodiment of the present invention, since the pre-sync area is provided after the VFO area, an error occurs in the first data synchronization sequence in the data area. However, the start timing of the head data block data can be detected with high reliability.

In the seventh embodiment, such a presync area will be described in more detail.

FIG. 14A shows the data format of one sector of the rewritable area of the optical disk according to the present embodiment, and FIG. 14B shows the data format of one sector of the read-only area. In FIGS. 14A and 14B, parts common to the data formats of the optical discs according to the embodiments described so far are denoted by the same reference numerals and correspond.

[0188] As shown in FIG.
Indicates a header area 80 (sector identification data PID1), a mirror area 12 (M) following the header area 80, and a gap area 13 (G
AP), first guard data area 23 (GD1), VF
O area 15, presync area 44 (PSY), first data area 17 (DATA), postamble 45 (P
A), a second guard data area 18 (GD2), and a buffer area 19 (BUF). The first data area 17 includes a plurality of data blocks 5a, 5b,.
And the first of each data block is
, Are arranged.

The mirror region 12 is a flat portion on which no pits or grooves are formed, and is used for taking a tracking offset. The first and second guard data areas 23 and 18 are areas for recording a predetermined data pattern in order to compensate for cycle deterioration due to heat load. The first guard data area 23 is located at the start of the recording data, and the second guard data area 18 is located at the end of the recording data. The gap area 13 is an area for absorbing signal disturbance at the data recording start end and setting the recording laser power. The VFO region 15 is the third
And a predetermined single-cycle code is continuously recorded. The pre-sync area 44 is a second data synchronization sequence shown in the present embodiment for specifying a data reproduction start position. Postamble 45
Is provided for terminating the modulation code and stably shifting the reproduction signal processing.

In the sector 30 of the read-only area, as shown in FIG. 14B, the pad area 82 (DMY) and the pad area 82 (DMY) are used instead of the gap area 13 and the first guard data area 23 of the recordable area. Postamble 8
3 (PA), instead of the second guard data area 18 and the buffer area 19, a pad area 85 (DMY)
By providing the postamble 86, the tracking stability is improved. However, the data arrangement (format) of the other parts is the same as that of the sector 10 shown in FIG. Hereinafter, the second data synchronization sequence arranged in the presync area 44 in the sector 10 of the recordable area and the presync area 46 in the sector 30 of the read-only area will be described in detail. In the following, the pre-sync area 44 in the sector 10 in the recordable area will be described as an example, but the same applies to the pre-sync area 46 in the sector 30 in the read-only area.

As described above, the data format according to the present embodiment uses the first data synchronization sequence 4a and the third data synchronization sequence (VFO region 1) arranged at the head of the data area.
5 or 84) has a data array to which a second data synchronization sequence (pre-sync area 44 or 46) is added. In order to detect a specific position in the code sequence, a specific pattern that has a strong autocorrelation and is not generated in other data portions is assigned to the second data synchronization sequence.

At the time of signal reproduction, first, the third data synchronization sequence (VFO area 15) is reproduced, and a PLL circuit pulls in a clock according to a single-cycle repetition pattern to stabilize the clock. After the clock is sufficiently stabilized, the position of the second data synchronization sequence (pre-sync area 44) is detected. From this detection position, the reading start position of the first data synchronization sequence 4a located at the head of the information data area can be specified. Next, by establishing synchronization with the data in the data area 17 using the first data synchronization sequence 4a,
It is possible to reproduce data at an even more correct timing.

When the data area 17 is divided into data blocks as shown in FIG. 14A, a plurality of first data synchronization sequences 4a, 4b,. The degree increases. Therefore, in order to secure a sufficient recording area for user data, it is necessary to shorten the length of one data synchronization sequence. On the other hand, since there is only one second data synchronization sequence (PSY44) in one sector, it is possible to make the length of the code sequence longer to ensure detection.

Therefore, according to the present embodiment, the position of the relatively long second data synchronization sequence (PSY44) can be reliably detected, and the detected second data synchronization sequence (PSY44) can be detected.
From the position (SY44), the read start position of the first data synchronization sequence 4a located at the head of the data area 17 can be specified. Thus, even if the first data synchronization sequence 4a is configured to be short, the detection can be performed stably.

Next, an example of a code pattern of the second data synchronization sequence will be described. In the present embodiment, as a recording code, 8 bits of data are converted into 16 bits of channel bits of the recording code, and an 8/16 code having a shortest bit length of 3 channel bits and a longest bit length of 11 channel bits is used. Here, the interval of one channel bit is represented by T. Also, an NRZI code is used to represent data. In the NRZI code, the signal level is inverted at bit “1” and not inverted at bit “0”. Also, the second data synchronization sequence needs to satisfy the mark / space length restriction by the recording code.

Therefore, the shortest recording bit length in this embodiment is "100". The code of the third data synchronization sequence (VFO area 15) has a longer period than the shortest recording bit length and more edge information (level reversal) that allows a reliable pull-in of the PLL in order to perform stable reproduction. Required to be included. Therefore, in this embodiment, the VFO area 15
Is used as a third data synchronization sequence to be recorded in the data sequence. Therefore, VF
The mark and space length in the O region 15 is 4T.

As described above, the pre-sync area 44
Is detected after performing clock synchronization from the third data synchronization sequence in the VFO area 15, so that the second data synchronization sequence is a code that can be synchronized every 4T.
Synchronous reproduction can be performed more reliably. Therefore, the second
It is effective to use a combination of 4-channel bit patterns as the data synchronization sequence.

On the other hand, when the average of the mark length and the space length of the second data synchronization sequence is close to the period of the repetition pattern of the third synchronization sequence in the VFO area (hereinafter, referred to as VFO pattern), the NRZI code is used. The resulting "1" exists at a similar position in the two code sequences. Therefore, when a bit error or the like occurs during reproduction, the probability of erroneously detecting the VFO pattern as the second data synchronization sequence increases. Therefore, in the present embodiment, the inter-code distance between the second data synchronization sequence and the VFO pattern is increased. However, in order to make the average of the mark length and space length of the second data synchronization sequence shorter than the period 4T of the VFO pattern, it is necessary to include a large number of patterns 3T, which is the shortest recording bit length, and to ensure stability during reproduction. Is impaired. Therefore, in this embodiment, the mark length of the second data synchronization sequence,
The average of the space length is set to be longer than the period 4T of the VFO pattern.

The second data synchronization sequence according to this embodiment is:
Code symbols having a length of 4 bits, in which level inversion is included only once, “0001”, “0010”, “0”
It is assumed that a code sequence is formed by combining a plurality of “100” and “1000” and a 4-bit code symbol “0000” in which level inversion does not occur.

Next, a more specific example of the code sequence forming the second data synchronization sequence will be described. Also in this embodiment, the above-described 8/16 modulation code is used. As described later, the first
Since a 2-byte code is used as the data synchronization sequence of
Three bytes are used as the second data synchronization sequence. When converted by the 8/16 modulation code, the recording channel bits have a length of 48 bits. If a combination of the above 4-bit code symbols is used, the length becomes 12 symbols. Hereinafter, four specific examples of the code sequence will be described.

(1) First Example of Code Sequence (Pattern 1) "0100 0010 0100 0010 0010 0010 0100 0100 1000 0010"
[0100 1000] Pattern 1 is the same as the pattern standardized in ISO / IEC 10089, and is "0100", "0010", "1000".
And three types of symbols.

(2) Second Example of Code Sequence (Pattern 2) "1000 0100 0100 1000 0010 0001 0000 1000 0010 0100"
0100 0001 "Pattern 2 is" 0100 "," 0010 "," 1000 "," 0001 "," 000 "
It is composed of five types of symbols "0".

(3) Third Example of Code Sequence (Pattern 3) "0000 0100 0100 1000 0010 0001 0010 0000 1000 0010"
[0001 0001 "Pattern 3 is composed of the same five types of symbols as pattern 2.

(4) Fourth Example of Code Sequence (Pattern 4) "0000 0100 0100 1000 0010 0001 0010 0000 1000 0010"
0001 0000 "pattern 4 is also composed of the same five types of symbols as pattern 2. As will be described in detail later, this pattern is a pattern uniquely found by the present applicant.
P arranged between the VFO area 15 and the data area 17
This is an example of a pattern that is resistant to errors and gives an excellent detection result as a data series of the SY area 44.

FIG. 15 shows, as a comparison of the characteristics of the patterns 1 to 4, the average of the mark length and the space length of each pattern,
The maximum and minimum values of the mark length and the space length, the types of symbols constituting the pattern, and the digital integrated value (D
(Absolute value of SV).

As shown in FIG. 15, the minimum value and the maximum value of the mark / space length generated in each pattern are 3T and 6T, respectively, and the limit value of the modulation by the 8/16 modulation code (the maximum length 11T, the minimum value). Length 3T).

It is preferable that the average mark / space length of patterns 1 to 4 be different from 4T which is the repetition period of the third data synchronization sequence, as described above. As can be seen from FIG. 15, the average mark / space length of pattern 1 is 3.7T, which is relatively close to 4T. This is because each of the three types of symbols constituting the code sequence of pattern 1 is a symbol in which one bit out of four bits always becomes "1". In particular, pattern 1 is "0000"
Therefore, it is difficult to make the average mark / space length longer than 4T.

On the other hand, the code sequences of patterns 2 to 4 are formed using five types of symbols including symbol "0000", and the average mark / space length can be made longer than 4T.

Also, as one of the indices representing the characteristics of the recording code, the recording code is represented by an NRZI code, and "1" of each bit is converted into a 1 value and "0" is converted into a -1 value to integrate all the codes. The digital integrated value (DSV) obtained can be used.
If the digital integrated value is zero, the DC component included in the recording code becomes zero, so that the DC component of the reproduction signal does not fluctuate, and the binarization of the reproduction signal can be performed stably. The digital integrated value of each pattern is as shown in FIG.

Next, detection of the second data synchronization sequence (PSY area) will be described.

FIG. 16 shows an example of the PSY detection circuit 200 for detecting the second data synchronization sequence. As shown in FIG. 16, the PSY detection circuit 200 includes a first shift register 91, a second register 92, a coincidence counter 93, a threshold circuit 94, a synchronization detection permission generation circuit 95,
And an AND circuit 96. In the present embodiment, as described above, the length of the second data synchronization sequence is 48 bits, and the twelve 4
The bit length symbols are S0 to S11. That is, the pattern of the second data synchronization sequence is the symbol sequence S0, S1, S2
2,..., S11.

First, patterns (symbol strings) S0, S1, S2,..., S11 of the second data synchronization sequence are stored in the second register 92. Then, the reproduction signal to be subjected to PSY detection is input to the first shift register 91 while being sequentially shifted. Then, every four bits, that is, for each symbol, the second
Detection with the synchronization sequence S0 to S11 (pattern match)
I do. The number of matching symbols is counted by the matching number counter 93, and the result is output to the threshold circuit 94. A threshold value for determining that the second data synchronization sequence has been detected is set in the threshold circuit 94 in advance, and when the count value counted by the coincidence counter 93 exceeds this threshold value , A detection signal is output from the threshold circuit 94.

For example, if the threshold value is set to 8, the threshold circuit 94 outputs the input reproduced signal and the second synchronization sequence S0 to S0.
A detection signal is output when S11 matches eight or more symbols. If there is no error in the reproduced signal, when the second data synchronization sequence is detected while shifting the contents of the first shift register 91 bit by bit, all 12 symbols match. The synchronization detection permission generating circuit 95 outputs a gate signal indicating a period during which the second data synchronization sequence is to be detected. When the threshold circuit 94 detects the second data synchronization sequence during this detection period, a detection signal of the second data synchronization sequence is output from the AND circuit 96 to a system control circuit (not shown).

In the present embodiment, pattern matching is performed for each 4-bit symbol.
For example, pattern matching may be performed in units of 1 bit.

Next, a specific example in which specific code patterns are assigned according to the data format shown in FIG. 14A (the same applies to FIG. 14B) will be described. FIG.
An example of a data format from the VFO area 15 to the first data block 5a is shown.

As shown in FIG. 17, it is assumed that at least 64 bits of a data sequence having a repeating pattern of "1000" exist in the VFO region 15 as a third data synchronization sequence. The first data synchronization sequence 4a of the data area 17 following the second data synchronization sequence of the PSY area 44
Is a 32-bit pattern 4a-1: "0001001001000100
000000000000010001 "or pattern 4a-2:" 00
01001000000100 0000000000010001 ". A data block 5a following the first data synchronization sequence 4a
Is an arbitrary 16 bits.

In the following, among the specific examples (patterns 1 to 4) of the above-mentioned second data synchronization sequence, pattern matches obtained in PSY detection for patterns 1 and 4 will be described.

Here, the second data synchronization sequence is shown in FIG.
The detection is performed using a 48-bit width detection window 97 as shown in FIG. If there is no error, the position where a match of 12 symbols should be obtained with respect to the second data synchronization sequence is set as a reference position, and the detection window 97 is shifted by -64 from the reference position.
The detection was performed by shifting in the range of +48 bits from the bit. Then, as described above, a comparison with the symbol of the second data synchronization sequence was performed every 4 bits of the input signal, and the number of pattern matches was obtained. The result is shown in FIG.
And 19B. The graphs shown in FIGS. 19A and 19B are generally called an autocorrelation function. Then, the threshold value of the pattern match is set to 8 symbols, and the position where 8 or more symbols match is set as the detection position of the second data synchronization sequence.

Here, in order to consider the influence of the first data synchronization sequence 4a and the data block 5a on the detection of the second data synchronization sequence, the results of FIGS. 19 (a) and 19B are as follows.
We are seeking as follows. Regarding the patterns 4a-1 and 4a-2 of the first data synchronization sequence, the value of the pattern match becomes larger at each time point (that is, the pattern that adversely affects the detection of the second data synchronization sequence). Is selected. When the detection window 97 is shifted to the right by about 40 bits or more from the reference position, a data block 5a subsequent to the first data synchronization sequence 4a is included in the detection window 97 as shown in FIG. Therefore, the pattern (16) of the data block 5a is used for detecting the second data synchronization sequence.
Bit) has a significant effect. Therefore, assuming the worst case, the pattern (16 bits) of the data block 5a giving the largest number of pattern matches is used.

As a result, FIGS. 19 (a) and 19 (b)
As can be understood from FIG. 5, the maximum value of the pattern match value when the detection window 97 is shifted to the left from the reference position (that is, the position of the bit shift 0) is 5 in the pattern 1, whereas it is 4 in the pattern 4. It is. Also, when the detection window 97 is shifted to the right from the reference position, the maximum value of the pattern match by pattern 1 is 6 in the range of 40 bits from the reference position, whereas it is 4 in pattern 4. It is desirable that the value of the pattern match when the detection window 97 is at a position other than the reference position be as low as possible in order to prevent erroneous detection of the second data synchronization sequence. Therefore, it can be said that pattern 4 has better autocorrelation characteristics with respect to bit shift.

Next, the autocorrelation of each pattern example of the second data synchronization sequence at the time of occurrence of an edge shift or slice variation is examined. The one-bit edge shift means that the reproduced signal is, for example, "00100" when it should originally be "00100".
01000 "or" 00010 ".
FIGS. 18A to 18C are diagrams illustrating slice fluctuation. The slice level is a reference for binarization of the reproduction signal, and binarization is performed by sampling the reproduction signal and setting the case where the value becomes larger than the slice level to "1". The result of the binarization is represented by an NRZI code. FIG.
As shown in (a), the reproduction signal is originally binarized by slicing at the center position of the amplitude of the reproduction signal. However, when the slice level rises as shown in FIG. 18B or when the slice level falls as shown in FIG. 18C, the reference for binarizing the reproduced signal is shifted. As a result, as shown in FIG. 18A, a signal sequence that should be reproduced as “10001000” by the NRZI code is reproduced as “10010000” when the slice level rises (FIG. 18B), "1 when descending
0000100 "(FIG. 18C).

FIGS. 20A and 20B show the worst value of the pattern match in the case where one to three edge bit shifts occur at arbitrary positions in the window 97 for detecting the second data synchronization sequence. Show. FIG.
0C is VFO due to the rise of the slice level.
The pattern of the area 15 changes from the original "10001000" to "10010000"
And the second data synchronization sequence in the PSY area has a similar variation, showing the result of pattern matching. Similarly, FIG. 20D shows the result of pattern matching when the slice level decreases. The results are shown.

As shown in FIGS. 20A and 20B, as the number of edge shift locations increases by 1, the value of the pattern match as a whole increases by 1 at almost all bit positions. As a result, in the case of the pattern 1, as shown in FIG. 20A, when two edge shifts occur, even at a position other than the reference position of the detection window 97, there is a position where the value of the pattern match is 8, and a false detection is performed. There is fear. However, in the case of pattern 4, even when two edge shifts occur, the maximum value of the pattern match at a position other than the reference position of the detection window 97 is 6, and the possibility of erroneous detection is small.

According to FIG. 20C, in the case of pattern 1, detection is performed by shifting detection window 97 from the reference position to the left (minus side in the figure) in the range of 64 bits to 48 bits, ie, VF with slice fluctuation
When a pattern match with the signal sequence in the O-region 15 is performed, there is a place where the value of the pattern match sharply increases (the value is 8), which may be erroneously detected as the second data synchronization sequence. There is. However, in the case of pattern 4, even when the slice level fluctuates, the maximum value of the pattern match on the left side from the reference position of the detection window 97 is 5, and the possibility of erroneous detection is small.

As described above, the second data synchronization sequence of pattern 4 has good characteristics as a recording code, and erroneously detects a synchronization signal even with respect to edge shift, slice level fluctuation, etc., as described in this embodiment. And the second data synchronization sequence recorded in the PSY area is preferable.

[0226]

As described above, according to the optical disk of the present invention, it is possible to reproduce the sector identification data of the first header area when tracking either the groove track or the land track. It is not necessary to provide a dedicated header area for each of the groove track and the land track.

Further, in the preformat of the rewritable area, the first header area is easily formed on the optical disk by wobbling the cutting beam forming the guide groove (groove track) from the center of the groove track to the inner and outer circumferences. And it can be formed with high precision.
Therefore, it is not necessary to separately provide a dedicated cutting light source in order to form the header area of the rewritable area.

Thus, according to the optical disk of the present invention,
Preformatting within the rewritable area can be accurately and easily realized using a single cutting light source. Therefore, even when the rewritable area and the reproduction-only area are mixed, the pre-formatting can be realized by using the conventional cutting machine.

As described above, according to the present invention, the length of a sector, the length of a header area, and the length of a data area to be recorded in each sector in a read-only area are determined.
The data format of the read-only area is matched with the data format of the rewritable area by making the length of the sector in the rewritable area, the length of the header area, and the length of the data area recorded in each sector the same. This makes it possible to unify the management of the sector between the read-only area and the rewritable area, and unify the processing such as sector search.

Further, according to the present invention, dummy data areas are added before and after the information data area in the read-only area, so that the length of the sector and the length of the header area in the read-only area and the data recorded in one sector are recorded. The length of the data to be written can be the same as the length of the sector in the rewritable area, the length of the header area, and the length of the data recorded in one sector. This makes it possible to unify the management of the sector in the read-only area and the rewritable area, and to unify processing such as sector search.

According to the optical disk of the present invention, even if the optical disk format has a rewritable area and a read-only area, it is not necessary to separately provide a reproduction signal processing circuit for the rewritable area and the read-only area. . Therefore, a common signal processing unit can be used, and the circuit scale of the optical disk recording / reproducing apparatus can be reduced, and a highly reliable reproduced signal processing circuit can be realized with a simpler circuit configuration.

Further, according to the present invention, even if the tracking servo in the read-only area is a phase error detection method, a tracking error signal can be detected stably, and relatively stable tracking servo can be performed. Further, by arranging different data synchronization sequences in the second dummy data area in the adjacent track, the tracking servo can be stabilized and the start point of the information data area can be reliably detected.

According to the present invention, the connection of the rewritable area is always started from the head of the track by supplementing the sector in which the dummy data is recorded to the unrecorded remaining sector of the read-only area. Thus, sector management can be performed efficiently.

According to the present invention, by using the second data synchronization sequence having strong autocorrelation in the presync area, the presync area can be detected with high reliability. It is possible to correctly specify the start timing position of the data area to be arranged. This makes it possible to stably reproduce the recorded data.

Further, as the configuration of the second data synchronization sequence, the average of the mark / space length in the second data synchronization sequence is made longer than the average of the mark / space length of the VFO region, so that the second data synchronization sequence is used in the VFO region. It is possible to make it difficult for pattern matching to occur with respect to the data synchronization sequence pattern to be obtained. Further, this effect can be realized even in a state where there is no error in the reproduced signal, or in a state where an edge shift occurs or a slice level fluctuates. Therefore, such a second data synchronization sequence is resistant to errors and can obtain an excellent detection result as a data sequence of a pre-sync area arranged between the VFO area and the data area.

Further, since the digital integrated value of the second data synchronization sequence is set to zero so as not to affect the fluctuation of the DC component, the stability of the reproduced signal is impaired by the addition of the second data synchronization sequence. Nothing.

Also, when the second data synchronization sequence satisfies the limit value on the modulation coding rule, the mark recorded on the optical disk is too small to cause waveform interference, or the mark is too large to cause signal interference. This has the effect of preventing the clock synchronization from becoming unstable due to a long inversion interval.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the arrangement of a rewritable area and a read-only area of an optical disc according to the present invention.

FIG. 2 is a diagram showing a data format and a reproduction signal of an optical disc according to one embodiment of the present invention.

FIG. 3 is a diagram showing a reproduction signal processing unit for reproducing an optical disk according to the present invention.

FIG. 4 is a diagram illustrating a data format and a reproduction signal of an optical disc according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating the principle of tracking control by a phase error detection method.

FIG. 6 is a diagram showing a waveform of a tracking error signal when the same data sequence is recorded on an adjacent track.

FIG. 7 is a diagram showing a waveform of a tracking error signal when a different data sequence is recorded on an adjacent track.

FIG. 8 is a diagram showing an example of a data format of a dummy data area according to one embodiment of the present invention.

FIG. 9 is a diagram showing an optical disk on which dummy data for sector control is recorded according to one embodiment of the present invention.

FIG. 10 is a diagram showing a data format of a rewritable area according to one embodiment of the present invention.

FIG. 11 is a diagram showing a data format of a read-only area according to one embodiment of the present invention.

FIG. 12 is a diagram showing a configuration example of a circuit for generating scrambled data according to one embodiment of the present invention.

FIG. 13 is a diagram illustrating an example of a conversion table of a modulation code.

FIG. 14 is a diagram showing a data format of a rewritable area and a read-only area of an optical disc according to one embodiment of the present invention.

FIG. 15 is a diagram illustrating a comparison of characteristics of each pattern of a second data synchronization sequence according to the present embodiment.

FIG. 16 is a diagram illustrating a configuration example of a second data synchronization sequence detection circuit.

FIG. 17 is a diagram illustrating a detection method and a detection range of a second data synchronization sequence.

FIG. 18 is a diagram illustrating a change in a slice level of binarization.

FIG. 19 is a diagram showing an autocorrelation function of pattern 1 and pattern 4 when there is no error in the reproduced signal.

FIG. 20A is a diagram showing a case where an edge shift occurs from one to three places in a synchronous pattern detection window;
FIG. 9 is a diagram showing an autocorrelation function of pattern 1 and pattern 4.

FIG. 20B is a diagram showing a case where one to three edge shifts occur in the synchronous pattern detection window;
FIG. 9 is a diagram showing an autocorrelation function of pattern 1 and pattern 4.

FIG. 20C is a diagram showing an autocorrelation function of pattern 1 and pattern 4 when the slice level changes.

FIG. 20D is a diagram showing an autocorrelation function of pattern 1 and pattern 4 when the slice level changes.

FIG. 21 is a diagram illustrating a conventional optical disc.

FIG. 22 is a diagram showing a conventional reproduction signal processing circuit for reproducing an optical disk.

FIG. 23 is a diagram showing a data format of a conventional optical disc.

──────────────────────────────────────────────────続 き Continuing from the front page (31) Priority claim number Japanese Patent Application No. Hei 8-1991887 (32) Priority date July 22, 1996 (July 22, 1996) (33) Priority claim country Japan (JP) Application for early examination (72) Inventor Isao Sato 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Toyoji Tokushima 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Yoshitaka 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-9-282667 (JP, A) JP-A-3-266236 (JP, A) JP-A-60-173733 ( JP A) Patent Akira 64-59632 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) G11B 7/00 - 7/013 G11B 20/12

Claims (4)

(57) [Claims] 1. An optical disc having a rewritable first recording area and a read-only second recording area, wherein the first recording area is a groove track as a groove portion and an inter-groove portion. A land track having a spiral or concentric first track alternately arranged, wherein the first track is divided into a plurality of first sectors; Has a first header area including sector identification data for identifying the first sector, and a first data area for recording data. The second recording area includes: A spiral or concentric second track in which a pit row having a physical unevenness is arranged has a plurality of second tracks.
Each of the plurality of second sectors has a second data area in which read-only data is recorded, and the first header area has a physical uneven shape. The first with
And a second pit row having a physical unevenness are included as the sector identification data. Each of the first pit row and the second pit row is substantially equal to the width of the groove track. And the first pit row is shifted from the center line of the groove track by about a quarter of the pitch of the groove track toward the outer periphery of the optical disk. The second pit row is formed at a position approximately one quarter of the pitch of the groove track from the center line of the groove track.
The first header area is formed at a position shifted in the inner circumferential direction of the optical disc, and the first header area is adjacent to the optical disc in the radial direction.
Groove track and land track
Is and, with the data recorded in the first data area, the second
The same change as the read-only data recorded in the data area
And the first data area and the second data area have the same data.
Data capacity and the same data format ,
optical disk. 2. Each of the plurality of first sectors includes a mirror mark area, a gap area, and a first dummy data area disposed between the first header area and the first data area. If, disposed between the first data area and the header area of the next first sector, further comprising a guard data area and buffer area, the optical disk according to claim 1. 3. The optical disk according to claim 2 , wherein the first dummy data area has a specific arrangement pattern of a modulation code used for modulating data to be recorded. 4. A reproducing apparatus for reproducing optical disks according to any one of claims 1 to 3, the first detector for detecting a signal from the first header region in the first recording area A second detector for detecting a signal from the first data area in the first recording area and a signal from a second data area in the second recording area; and the first detector A reproduction device comprising: a switch unit for selectively outputting one of the output of the first detection unit and the output of the second detection unit; and a reproduction unit for generating a reproduction signal based on the output of the switch unit.