JP2686802B2 - Recording method for optical disc - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a recording method for an optical disc partially having a read-only area and a writable area or once-writable area.

[Conventional technology]

A continuous servo method and a sample servo method are known as tracking methods for optical disks. The continuous servo method is a method of tracking using a groove that is continuously formed, and when recording data, a modulation method with a self-clock signal can be used to accurately synchronize using the signal itself. However, since the header part that disturbs the above-mentioned modulation method is at the head of the sector, it is necessary to resynchronize the data for each sector.

The sample servo method performs synchronization, tracking, and focusing in servo areas provided at 1000 or more places per revolution, and it is not necessary to resynchronize for each sector, but disk eccentricity, uneven rotation, and external If the synchronization is lost due to a shock or the like, the signal cannot be reproduced.

FIG. 6 is a diagram showing a sector format of a conventional continuous servo type optical disk planned by ISO.

In the figure, 4 is a groove-shaped track formed in a spiral shape at intervals of 1.6 μm, and information is provided between the tracks 4, 4 ... Or on the tracks 4, 4 ... (between the tracks 4, 4 ... In this example). Read-only and / or rewritable bit that records
PT, PT ... Are formed with a diameter of approximately 1 μm. One track is recorded in a format of 17 sectors, one sector is 1360 bytes, or one track is 31 sectors and one sector is 746 bytes. The sector is pre-formatted with 52 bytes of sector identification information and address information. Header section SH, SH, 1-byte mirror section MM, MM for detecting focus error, 13-byte gap flag ALPC area GFA, GFA, 12-byte PLL pull-in preamble section VFO, VFO, 3-byte synchronization Pattern part SP, SP
And a data portion SD, SD including a user area of 1024 bytes or 512 bytes is formed in this order.

FIG. 7 shows the format of the error correction code in one sector. This has a format of 1024 bytes as the user area, and is a 10-interleaved (rearranged) Reed-Solomon code with a code length of 120 and a minimum distance of 17 that composes a code word on GF (2 ⁸ ). D1 ~ E10,16
Is a 1-byte block, and 120 blocks in the vertical direction are configured as codes. These are 10-word codes (C0 ~
C9) Collectively constitutes an error correction code within one sector.

Since the minimum distance for error correction is 17, eight errors can be corrected per word code, and up to 80 continuous bytes can be corrected in one sector in the recording direction.

To prevent erroneous correction, CRCC (Cyclic Redundancy Check Code: CRC-1 to
This is done by adding CRC-4).

[Problems to be solved by the invention]

If a defect of about 100 μmφ, which is considered to be the maximum disc defect, occurs at the beginning of the data section of the sector of the optical disc
About 63 tracks (100 μm ÷ 1.6 μm = 62.5) in the number of tracks, the sync pattern portion SP of the same sector is damaged and data cannot be reproduced.

On the other hand, in the circumferential direction, 100 μm corresponds to 100 recorded bits, which is about 6 bytes as source data.
Even if there is a defect of mφ diameter, the sync pattern portion SP is not damaged across two sectors, and only one sector cannot be reproduced.

In the case of writable area or once writable area, verify after recording and write the data of the area where an error of more than a certain number of bytes has occurred due to the defect to another area to prevent unreadable data due to the defect. However, the synchronization pattern part SP of the sector in the read-only area of the optical disc
If there is a defect across tracks, the error cannot be corrected by the Reed-Solomon code error correction circuit in the sector.
There is a problem that the data in that sector cannot be reproduced.

This also applies to the sample servo type optical disk, and if a defect extending over a plurality of tracks occurs in the vicinity of the sync bit in the read-only area, error correction cannot be performed and reproduction becomes impossible.

The present invention has been made in view of such circumstances,
By generating check data for correcting those errors from the data recorded in the read-only area and recording the check data at a predetermined position in the read-only area, a synchronization pattern of sectors over a plurality of tracks in the read-only area. An object of the present invention is to provide a recording method for an optical disc that can reproduce data even if a part is damaged due to a defect.

[Means for solving the problem]

A recording method for an optical disc according to a first aspect of the present invention is a recording method for an optical disc having a track provided in a radial direction and a sector provided in a circumferential direction, a part or all of which is a read-only area. The area of the read-only area over a plurality of continuous radial tracks.
It is characterized in that a block is formed, and check data generated from sectors recorded over a plurality of blocks and correcting the error of those sectors is recorded at a predetermined position of the block.

A recording method for an optical disc according to a second aspect of the present invention, when the data recorded in a sector is corrected by the check data, records the corrected data in the recordable area of the optical disc. It is characterized in that the recorded address and the address where the corrected data is recorded are recorded as map information.

[Action]

According to the first and second aspects, an area extending over a plurality of continuous tracks in the radial direction of the read-only area is defined as one block, and the check data generated from the sectors recorded over a plurality of blocks is recorded at a predetermined position of the block. By doing so, for a defect that tends to occur across a plurality of tracks in the radial direction rather than in the longitudinal direction of the track, the sync signal of the data portion cannot be obtained in the normal reproducing operation, and the reproduction cannot be performed. In this case, the data can be easily reproduced, and when the erroneous data is reproduced, the data recorded separately and corrected by the map information can be used for the reproduction, so that the reproduction speed of the data is high. Become.

[Embodiment] The present invention will be described below with reference to the drawings illustrating an embodiment thereof.

FIG. 1 is a schematic diagram showing a configuration of a recording section of an optical disc used for carrying out a recording method for an optical disc according to the present invention. The optical disc has a diameter of 90 mm and its radius is 23.5 mm ~
Information is recorded in the recording unit 1 between 40.5 mm. The recording unit 1 is divided into 22 sectors # 0 to # 21 in the circumferential direction.
The inner peripheral side of the recording portion 1 is a read-only area 2 in which information is recorded by bits, and the outer peripheral side is formed with a writable area 3 by magneto-optical recording. Further, the recording unit 1 is provided with spiral tracks 4 at intervals of 1.5 μm. On the tracks 4 or between the tracks 4, 512 bytes of user data and error detection are made in a 1-sector data area.
The correction code is recorded.

FIG. 2 is a diagram showing the structure of tracks and sectors in the read-only area. Sectors S _{0 to} S ₂₁ are composed of a header section SH and a data section SD, and the data section SD is an area of 512 bytes of user data. And error detection and correction code areas are provided.

Predetermined information is recorded in pits in the data area. The first 7n track T _7n ~ first 8n-1 track T _8n-1 of the 21 sectors of 512 bytes of user data and error detection generated by the procedure described below in the data area S _21, the n-number of the correction code Error check data Cd _{0 to} Cd _n-1 are recorded.

 Next, a procedure for generating check data will be described.

FIGS. 3 and 4 are diagrams for explaining the procedure for generating the check data, in which the optical disk shown in FIG.
(N: natural number) A track is one block, and 8 blocks of ₀ to 7 blocks B _{0 to} B ₇ are considered.

And the first track T ₀ , T _n , of each block B _{0 to} B ₇
As shown in FIG. 3, information in each data area is added with symbols g _{0 to} g ₁₇₅ in the order of blocks B _{0 to} B ₇ of each sector S _{0 to} S ₂₁ of T _2n ... T _7n , and information g _{0 to} g ₁₇₄ The exclusive OR of each byte of 175 pieces of information is recorded as information g ₁₇₅ in the 7nth track as shown in FIG.
It is recorded in the 21st sector S ₂₁ of T _7n . This information g ₁₇₅ becomes the check data Cd ₀ . Similarly, the next track T ₁ , T _{n + 1} , T _{2n + 1}
... T _{7n + 1} information g ₀ writes check data Cd ₁ of exclusive OR to g ₁₇₄ to a 7n + 1 tracks T _{7n + 1} of the 21 sectors S _21, the last track T _n-1, T _{2n- 1} … Information of T _8n-1 g _{0 to} g ₁₇₄
8n-1 as the exclusive OR of check data Cd _n -1
Write to the 21st sector S ₂₁ of track T _{8n-1 with} a total of 512 512
Check data Cd _{0 to} Cd _n-1 of byte user data and error detection / correction code is created.

Check data Cd _{0 to} Cd _n-1 created in this way
Is recorded in a predetermined sector when recording information on the optical disc, even if the synchronization pattern portion of a certain sector is damaged by a defect over n tracks, information and check data Cd _{0 to} Cd for every n tracks. The information of the sector where the sync pattern portion is damaged can be reproduced by _n-1 and the position information of the damaged sector.

However, although eight blocks are considered in the above embodiment, the number of blocks is not limited to this value.

When the information of the damaged sector is correctly demodulated by the information for every n tracks, the check data Cd _{0 to} Cd _n-1 and the position information of the damaged sector as in this embodiment, the damaged portion correctly demodulated. By recording the information of the sector in a predetermined area and recording the damaged track and sector number and the newly recorded track and sector number as a map in the predetermined area, in each subsequent reproduction, It is not necessary to refer to the check data to correct the error, and the access speed is improved.

 Next, another embodiment will be described.

In the above-described embodiment, the exclusive OR of each information is obtained and used as the check data Cd _{0 to} Cd _n-1 , so that correction cannot be performed if the information and the check data for every n tracks are damaged by 2 sectors or more. In this embodiment, an error correction code with two types of check data added is created.

FIG. 5 is a diagram showing an error correction code generation procedure of another embodiment and corresponds to FIG. 3 of the first embodiment. In this embodiment, the same element that constitutes the Reed-Solomon code used in one sector is used, and an error correction code with a minimum distance of 3, that is, 2 symbols added as check data is considered. 16 as data format for every n tracks
Consider blocks B _{0 to} B ₁₅ of. Then, the exclusive OR of the information of the adjacent odd numbered and even numbered sectors is obtained. For example, as shown in FIG. 5, the information is sequentially assigned the symbols g ₀ to g ₃₄₉ , and the exclusive OR of the information g ₀ and the information g ₁ is the same as h ₀ and the information g _2.
If g ₃ and h ₁ are set, the exclusive OR of 175 of exclusive ORs h _{0 to} h ₁₇₄ can be obtained. The information is compressed from 350 to 175 because the Reed-Solomon code having an element on GF (2 ⁸ ) can only have a code length of 255. Based on this, two types of check data C1d _{0 to} C1d _n-1 and C2d _{0 to} C2d _n-1 are generated by an error correction method such as Reed-Solomon code, and they are generated in the 15th _nth sector of sector S ₂₀ and sector S ₂₁ . Truck T _15n ~
The 16th-1th track T _16n-1 is recorded on the nth track.

As a result, even if there are two errors in the information of the exclusive ORs h _{0 to} h ₁₇₄ of 175 and the two check data, it is possible to correct and reproduce by the position information of the damaged sector and the two check data. Also in this embodiment, by recording the corrected reproduction data and map information in a predetermined area, subsequent access can be speeded up.

Although the present invention is applied to the optical disk having the writable area and the read-only area and the error correction code between the sectors is applied only to the minimum areas 2 and 3 in the above two embodiments, the present invention is not limited to this. Needless to say, the present invention can be applied to any optical disk of the sample servo and continuous servo systems.

〔The invention's effect〕

As described above, according to the present invention, the data in the read-only area is generated at each predetermined area of the block by generating the check data for each area over a plurality of tracks in the radial direction, and is recorded at the predetermined position of the block. Even if the data is damaged over a plurality of tracks in the radial direction, the information of the damaged sector can be reproduced by the check data. Further, since the data format of the sector in the read-only area is the same as the data format of the sector in the writable area, there is an excellent effect that the hardware of the apparatus for recording / reproducing information on / from the optical disc can be changed little.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a recording section of an optical disc used for carrying out a recording method for an optical disc according to the present invention,
FIG. 2 is a diagram showing the structure of tracks and sectors in the read-only area, FIGS. 3 and 4 are diagrams showing a check data generation procedure, and FIG. 5 is a diagram showing a check data generation procedure of another embodiment. FIG. 6 is a diagram showing a sector format of an optical disk used in a conventional recording method, and FIG. 7 is a diagram showing an error correction code format in one sector. 1 ...... recording unit, 2 ...... read-only area, 3 ...... writable region, 4 ...... track, Cd ₀ ~Cd _n-1 ...... check data In the drawings, the same reference numerals are the same or corresponding parts Show.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryuichiro Arai 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation Industrial Systems Research Institute (72) Inventor Kazuhiko Nakane 8-chome Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture No. 1 Mitsubishi Electric Corporation Industrial Systems Research Institute (72) Inventor Masami Shimamoto 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation Industrial Systems Research Institute (56) Reference JP-A-63-298778 (JP, A) JP 60-115071 (JP, A) JP 57-205831 (JP, A) JP 63-14379 (JP, A)

Claims (2)

(57) [Claims] 1. A recording method for an optical disc having a track provided in a radial direction and a sector provided in a circumferential direction, a part or all of which is a read-only area, the method comprising: An area that extends over a plurality of continuous tracks in the radial direction is defined as one block, and check data that is generated from sectors recorded over a plurality of blocks and corrects errors in those sectors is recorded at a predetermined position in the block. A recording method for a characteristic optical disc. 2. When the data recorded in the sector is corrected by the check data, the corrected data is recorded in the recordable area of the optical disc, and the address and the correction in which the data before the correction is recorded are recorded. 2. The recording method for an optical disc according to claim 1, wherein the address where the subsequent data is recorded is recorded as map information.