JP2674597B2 - Data recording method for optical disk - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk data recording method applicable to, for example, a document file device. 2. Description of the Related Art An optical disk recording apparatus performs recording by, for example, irradiating the signal surface of a disk with recording laser light modulated by a digital recording signal and forming pits on the signal surface by the light energy. During playback,
The reading laser light is applied to the signal surface of the disk to obtain digital reproduction signals corresponding to the pits and lands. A large number of data tracks are formed on the disc, and addresses are recorded in advance at predetermined positions on the data tracks. When recording the data, if the target address is played while playing the address,
It is designed to record data. In order to perform the above-mentioned recording, the optical disc is provided with an address section and a data section for recording data. However, if the laser light power is not switched to the power required for recording by the time the laser light reaches the beginning of the data section after the target address is reproduced, the reliability of the recorded data will be impaired. There was a risk that Further, if the reproduction address is wrong, there is a problem that the data is written to the wrong address. Therefore, an object of the present invention is to record data after the target address is reproduced.
It is an object of the present invention to provide a data recording method for an optical disc, which can surely switch the laser power to a power required for recording and which can prevent the reproduction address from containing an error as much as possible. According to the present invention, a track is divided into a plurality of sectors, and each sector has an address having a code indicating an address of the track and the sector and an error detection code for the code. A signal is pre-recorded a plurality of times, and a sync signal for synchronizing with the address signal is pre-recorded corresponding to each address signal, and a data part for recording digital data. , After the target address is detected on the basis of the address signal recorded in the address section of the optical disc having a gap provided between the address section and the data section, the laser beam from the laser generating means is detected at the gap. The power is switched from the power for playback to the power required for recording, and the cell corresponding to the target address is selected. A data recording method for an optical disc, characterized in that digital data is recorded in a data section of the optical disk. The address signal recorded in the address section is reproduced to detect the target address. And
Digital data is recorded on the track and sector designated by the address. According to the present invention, since the gap is provided between the address portion and the data portion, the power of the laser beam is required for recording from the detection of the target address to the recording of the digital data in the data portion. It is possible to ensure that the data is switched to another one, and the reliability of the recorded data can be increased. Furthermore, since the address signal is recorded a plurality of times in the address portion, it is possible to avoid the error from being included in the reproduced address signal due to an error that occurs when the address portion is reproduced. BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. In FIG. 1, reference numeral 1 denotes a disk, which is rotated by a spindle motor 2 at a constant angular velocity or a constant linear velocity. The disk 1 is formed by coating the surface of a substrate made of glass or synthetic resin with a metal layer such as bismuth and plating the surface. In the disk 1, a recording laser beam from the optical head 3 causes a phase transition of its metal layer to form a pit. On the other hand, the pits are read by the reading laser light from the optical head 3. The recording laser light is modulated by the write data. A large number of spiral tracks are formed on the disk 1, and each track is divided into a plurality of sectors. The address section for each sector is recorded in advance on the disc 1, and the address reproduced from the address section allows a digital signal to be recorded in the target sector or reproduced from the target sector. There is. The optical head 3 has an objective lens, a beam splitter, an optical modulator, a light receiving element, etc., and laser light is applied to the optical head 3 from a laser generation circuit 4 including a semiconductor laser. Write data is supplied to the optical head 3 from a drive interface 5 via a laser generation circuit 4 including a semiconductor laser, and read data read by the optical head 3 is taken out via the drive interface 5. When writing (recording),
A power control signal is supplied from the drive interface 5 to the laser generation circuit 4 in order to further increase the power of the laser light as compared with the reading (reproducing) time. A servo circuit 6 is provided to rotate the disk 1 at a constant angular velocity or a constant linear velocity. Further, the optical head 3 can be sled in the radial direction of the disk 1 by a sled feeder 7 composed of a linear motor. Focusing and tracking of the optical head 3 are improved by the focus and tracking servo 8. The reproduction output of the optical head 3 is supplied to the system controller 9 for detecting a focusing error and a tracking error. A command is supplied to the system controller 9 via the drive interface 5, and a control signal for the servo circuit 6, the sled feed unit 7, the focus and tracking servo 8 is generated from the system controller 9. The drive interface 5 has the structure shown in FIG. In FIG. 2, reference numeral 21 denotes a block coding encoder that converts 8 bits into a preferable pattern of 10 bits, that is, a pattern that can reduce the DC component. The output of the encoder 21 is supplied to the parallel-serial converter 22 and the write data is written. It is formed. The read data from the optical head 3 is supplied to the serial / parallel converter 24 and the PLL 25 via the limiter 23. The output of the serial / parallel converter 24 is a block coding decoder 26 and a sync / mark detection circuit 27.
And supplied to. The PLL 25 extracts a bit clock from the read data and supplies this bit clock to the decoder 26 and the sync / mark detection circuit 27. The sync / mark detection circuit 27 detects the sync signal and the mark (address mark or data mark) in the read data, generates a timing signal synchronized with the read data, and supplies this timing signal to the decoder 26. Further, the drive controller 28 generates a command for the drive system controller 9 and a power control signal for the laser generation circuit 4. The formation of write data, the processing of read data, and the formation of data in the drive controller 28 are performed by the error correction code processor 11, memory 12, and system controller 13. Further, the computer 15 and the optical disc recording / reproducing apparatus are coupled via the interface 14. The error correction code processor 11 performs an error correction coding process at the time of recording, converts the error correction coded recording data into write data of a predetermined format, and at the time of reproduction, an error of the read data. The correction process is performed. The error correction code is a compact disk error correction code (CIRC code) jointly developed by the applicant of the present application and Philips.
The same as described above is used. That is, in this error correction code, first, the interleaved 16-byte data is encoded by the (20,16) Reed-Solomon code, and then the 20-byte data is interleaved again. , (24, 20) Reed-Solomon code is encoded. The error correction is performed by performing deinterleaving and decoding of Reed-Solomon code. The system controller 13 controls processing such as encoding, decoding, and format formation. A format in one embodiment of the present invention will be described with reference to FIGS. 3 and 4. As shown in FIGS. 3A and 4A, one track is divided into 20 sectors (0 to 19) when the angular velocity is constant, and
When the linear velocity is constant, the number of sectors is divided according to the length of one track. Data is written and read in units of this sector. Each sector includes an address part and a data part, as shown in FIGS. 3B and 4B. The address part is recorded in advance on the disc by the manufacturer. As shown in FIG. 3C, the address part is formed by sequentially recording the same address 0, address 1, and address 2. A 16-byte sync signal is located at the beginning of the address part. This sync signal has a bit pattern of (AA ... A) in hexadecimal notation. FIG. 3D shows the number of bytes and the bit pattern of the first part of the address part. After this sync signal, an address 0 consisting of a 2-byte address mark, a 2-byte track number, a 1-byte sector number and a 2-byte CRC code is located. 1 byte of this data is 10 by encoding 8 → 10 conversion.
It is converted to bits and recorded on the disc. The sync signal is a pulse signal having a repetition frequency equal to the highest frequency generated by the 8 → 10 conversion, and is used as an amble signal for bit synchronization. The address mark has a peculiar bit pattern (C936A bit pattern in hexadecimal notation) that does not occur in the data recorded in the data section and that bit synchronization is not easily lost. This address mark is used for word synchronization. The track number and the sector number are addresses of the track and the sector, and a CRC code (error detection code using a cyclic code) is added for error detection of both. A 3-byte sync signal is interposed between address 0 and address 1 and between address 1 and address 2. This sync signal is a pulse signal having the same frequency as the sync signal at the beginning of the address part, and prevents the bit synchronization from being lost. Recording the same address three times in the address part is a countermeasure against an error. That is, among the reproduced addresses, as a result of the error detection of the CRC code, the address that has no error is validated. However, in the case of triple-recording the addresses, since the sync signal is inserted at the boundary between the two addresses, both of the two addresses become an error due to the facilitation of bit synchronization and the burst error generated at the time of disk reproduction. Is prevented. In this embodiment, since the length of the burst error that occurs during disc reproduction rarely exceeds 3 bytes (30 bits on the disc), the length of the sync signal inserted between the two addresses is 3. I have a bite. In this way, even if a burst error occurs at the boundary of two addresses, 1
It is possible to prevent only the error of one address and the sync signal, and to prevent an error of both these two addresses. Also, the reliability of word synchronization can be improved by repeatedly inserting the address mark a plurality of times. When the first address mark is detected, the address marks from the second one generate a correct window. This window has a window width of, for example, ± 4 bits. Even if the bit pattern of the address mark is shifted up and down by 9 bits within this window width, the minimum Hamming distance is 5 bits, so that the address mark can be correctly detected even if a 2-bit error occurs in the address mark. Further, the end of the address part, that is, address 2
A gap is provided between the rear end of the CRC code and the next data section. This gap is provided in order to compensate for the rising time from the detection of the target address to the generation of laser light of sufficient power for recording. For example, the length of the gap between the address part and the data part is 10 bytes. FIG. 4C shows the format of the data part, and FIG. 4D shows the number of bytes and the bit pattern of the head part of this data part. The data section includes a sync signal and a data mark in addition to the error correction coded data. A 16-byte sync signal is inserted at the beginning of the data section. This sync signal is 8 → 1
It is a pulse signal having a repetition frequency equal to the highest frequency generated by 0 conversion, and is for pulling in bit synchronization. A 2-byte data mark 0 is inserted after this sync signal. The data mark 0 has a unique bit pattern (C639A in hexadecimal notation) and is used for data synchronization. Sixteen sets 0 to 15 are inserted after the data mark 0.
Each set consists of a data mark 1 of a unique bit pattern of 2 bytes (36C95 in hexadecimal notation) and 96 bytes of data. One sector contains 1.5 Kbytes of data. With this 1 sector data as a unit, the CIR
The C code is encoded, and the interleave is 1
It is designed to be completed within a sector. Similar to the address mark described above, a plurality of data marks are recorded in the data portion within one sector, and even if the word synchronization is lost in the middle of the data mark, subsequent data may be invalid. To be prevented. A gap having a length of 30 bytes, for example, is provided at the last position of the data portion of each sector. The gap between the sectors becomes longer than the specified length due to the compensation of the fall time of the recording light, the uneven rotation of the disc, the eccentricity of the disc, etc., and it overlaps with the beginning of the next sector. This is to prevent this. The data recorded on the disc is 8
Channel coding other than block coding of → 10 conversion may be applied. Further, the sync signal is not limited to the pulse signal of the highest frequency generated after the 8 → 10 conversion, but a signal having a periodicity such as a pulse signal of a frequency that is an integer fraction of this highest frequency can be used. According to the present invention, after the target address is detected based on the address signal recorded in the address section, the power of the laser beam from the laser generating means is reproduced at the gap. The power of the laser is switched to a power that is sensitive to recording, and the digital data is recorded in the data part of the sector corresponding to the target address, so ensure that the power of the laser light is switched to that required for recording. Therefore, the reliability of the recorded data can be increased. Further, in the present invention, since the address signal is recorded in the address portion a plurality of times, it is possible to avoid the error from being included in the reproduced address signal due to an error occurring when the address portion is reproduced. You can

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an example of an optical disc recording / reproducing apparatus in which the present invention is used. FIG. 2 is a block diagram of a part of the configuration of the optical disc recording / reproducing apparatus of FIG. FIG. 3 is a data format of one embodiment of the present invention,
In particular, it is a schematic diagram showing the configuration of the address part. FIG. 4 is a schematic diagram showing the format of one embodiment of the present invention, particularly the configuration of the data part thereof. [Explanation of reference numerals] 1 ... disk, 3 ... optical head, 4 ... laser generation circuit, 5 ... drive interface, 11
... Error correction code processor

Continuation of front page    (56) References JP-A-55-67948 (JP, A)                 JP-A-57-78640 (JP, A)                 JP-A-55-153183 (JP, A)                 JP-A-57-33441 (JP, A)                 JP-A-57-172533 (JP, A)                 JP-A-58-57674 (JP, A)                 JP-A-57-103563 (JP, A)                 JP-A-58-177753 (JP, A)

Claims (1)

(57) [Claims] A track is divided into a plurality of sectors, and each sector is prerecorded with an address signal having a code indicating an address of each of the track and the sector and an error detection code corresponding to the code. In addition, a sync signal for synchronizing with the address signal is pre-recorded in correspondence with each of the address signals, a data part for recording the digital data, and the address part. After the target address is detected on the basis of the address signal recorded in the address section of the optical disc having a gap provided between the laser section and the data section, The power was switched from the power for playback to the power required for recording, and the above-mentioned target address was supported. Data recording method for an optical disc, characterized in that for recording digital data to the data portion of the connector.