JPH0576113B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention records and reproduces information on an optical recording disk that has an optically detectable guide track and in which the guide track is divided in advance into a plurality of sectors. This invention relates to an optical information reproducing method.

Conventional structure and its problems As an optical information recording/reproducing device, for example, an optical recording disk coated with or vapor-deposited with a photosensitive material is rotated, and a light beam from a laser light source is narrowed onto the disk surface. By irradiating spot light and modulating its optical output intensity with a recording signal, an information signal is recorded on an optical recording disk as an optical change such as a phase change due to unevenness or a change in reflectance or transmittance, and There are devices that can reproduce recorded information by detecting optical changes.

In such devices, for reasons such as reduction of the recording track pitch, discrete partial writing, and erasing, the track to be recorded becomes an optically detectable guide track, and a microscopic spot light from a laser is used. A method is often used in which known tracking control is applied to follow the guide track, information is recorded on a predetermined track, and information is reproduced from the track.

Furthermore, when recording digital information whose data length is variable, some devices divide the track into a plurality of areas (sectors) in order to use the recording area efficiently. For sector identification, each sector has an address field written in advance at the beginning of each sector, as shown in A in Figure 1, and the recording signal is written in the address part A as shown in B in Figure 1. Recorded in divided areas. Address portion A generally records a track address and a sector address.

FIG. 2 is a diagram showing details of the format of a signal actually recorded on an optical disc. 1 is a synchronization signal to prompt the clock to synchronize during data reproduction, 2 is a data mark using a certain code to indicate the beginning of data, and 3 is a data mark with redundant bits added based on error correction code theory. , is interleaved encoded data.

FIG. 3 is a block diagram of an optical information recording/reproducing section for writing and reading data in sectors on an optical disk.

The optical head 4 receives the output signal c of the drive circuit 5.
Based on this, information is recorded on the optical disc, and during reproduction, a reproduction signal output d is sent to the RF reproduction circuit 6.
Referring to FIG. 2, a sector writing operation to an optical disk will be explained. The write data is transferred to the buffer memory 8 under the control of the CPU 7. Next, CPU8 is
After searching for a track for writing data, the sector address for writing data is set in the sector address register 9. Reference numeral 10 denotes a circuit that reproduces a sector address from the output of the RF reproduction circuit 6. The output of the sector address register 9 and the output of the sector address reproduction circuit 10 are compared in a sector address coincidence detection circuit 11. When the output of the sector address reproducing circuit 10 matches the output of the sector address register 9, the output a of the read/write control circuit 1
3, and the output b of the read/write control circuit 13
Accordingly, the data in the buffer memory 8 is modulated by the data modulation circuit 12 and input to the drive circuit 5.

The drive circuit 5 operates to light the recording material of the optical disc at a low optical output level that does not record when reading the recording material, and to perform threshold recording by modulating the light at a sufficient optical output level during writing. When the data in the buffer memory 8 is written to the target sector, the read/write control circuit 13 controls the drive circuit 5 to set the optical output of the semiconductor laser to a low optical output level for reading, and performs the next reading or writing. Be prepared.

Next, the case of sector reading will be explained. When the read sector is detected by the sector address coincidence detection circuit 11, the output of the RF regeneration circuit 6 is data regenerated by the data regeneration circuit 14 and written into the buffer memory 8.

In the conventional optical information recording and reproducing apparatus as explained above, it is assumed that the address part shown in FIG. If it is, that sector cannot be written to or read from. In particular, the problem is that when writing data, address part A is correctly reproduced, and after writing is completed, when attempting to read data from the same sector, an error in reading address part A of that sector is detected. This is the case.
Such a phenomenon may occur due to scratches or dust adhering to the address portion A of the recorded sector after data recording.

Purpose of the Invention The present invention provides an optical recording disk that has an optically detectable guide track, and the guide track is divided in advance into a plurality of sectors. To enable data in a sector to be read even if the address of the sector is not correctly reproduced.

Structure of the Invention The present invention provides that, when reading data written on a sector-structured optical disk, if the address part of a sector is not read out correctly, a sector before that sector is read out, and the address part is read out correctly. By starting data read from the address section and reading data continuously up to the sector whose address part is not read correctly, it is possible to read data from the sector that has become unreadable.

DESCRIPTION OF THE EMBODIMENTS FIG. 4 shows a specific configuration diagram for realizing the read/write control circuit 13 of FIG. 2 in one embodiment of the present invention.

20 is a down counter.

In the CPU 7, the number of data to be read is set in advance via the load terminal (LD) counter input terminal. Thereafter, when the CPU 7 sets a sector address in the sector address register 9, when the output of the sector address reproduction circuit 10 and the set sector address match, the output a of the sector address match detection circuit 11 is It is input to the preset input of the flip-flop circuit 21, and the Q output of the flip-flop circuit 21 becomes high level. Q of flip-flop circuit 21
The output is input to the count enable terminal (EN) of the down counter, and the data clock input to the clock input terminal (CK) is counted only while the Q output of the flip-flop circuit 21 is at a high level. This data clock is a pulse that is generated once per unit of data read during data read. When the down counter 20 counts the data clock by the set number of data, a carry occurs, the flip-flop 21 is cleared, and the Q output b of the flip-flop 21 becomes low level.

To implement the present invention using the read/write control circuit 13 configured as described above, the following procedure is used. That is, because the sector address of a certain sector in which data has already been written cannot be read correctly, the output a of the sector address match detection circuit 11 does not go to a high level.
Assume that data reading becomes impossible for this reason.
At this time, if the address of the immediately preceding sector can be read correctly, the following operation may be performed depending on whether data is recorded or not.

(1) When data is recorded in the immediately preceding sector: The CPU 7 sets the immediately preceding sector address in the sector address register 9, and sets the data amount for two sectors in the down counter 20 shown in FIG.

(2) When no data is stored in the immediately preceding sector The CPU 7 sets the immediately preceding sector address in the sector address register 9, and sets the data amount for one sector in the down counter 20 shown in FIG.

By performing the above operations, the data of the sector whose sector address cannot be read correctly can be finally read out and obtained as one sector's worth of data.

The above explanation relates to the case where the sector address of the sector immediately before the sector whose sector address cannot be read correctly can be read, but the present invention is not limited to such a case; If there is a sector whose sector address can be read before the sector that cannot be read correctly, and if you know the total amount of data recorded from that sector to the sector you are trying to read data from, then you can similarly read the data. be.

In addition, in addition to the data used by the user, the address information of the sector to be recorded is additionally recorded in the data to be recorded, and after obtaining the data using the method described above during playback, the By reading the sector address and confirming the sector address, data reliability can be improved.

Effects of the Invention According to the invention described above, it is possible to obtain data in a sector whose sector address cannot be read correctly after data is recorded.

[Brief explanation of the drawing]

FIG. 1 is a time chart showing the arrangement of the address part and data part of a sector, and FIG. 2 is a diagram showing the format of a signal recorded on an optical recording disk.
FIG. 3 is a block diagram of an optical information recording/reproducing section for writing and reading data in sectors on an optical disk, and FIG. 4 is a circuit diagram showing a circuit configuration for implementing the present invention.

Claims (1)

[Claims] 1. An optical information reproducing method for reproducing information by focusing a laser beam minutely onto an optical recording disk having a guide track divided into sectors having data recording areas following an address signal, the method comprising: a desired sector; When the address of this desired sector cannot be read correctly when reproducing the address, the total amount of data from the sector before the address unreadable sector whose address cannot be read and whose address can be read to the address unreadable sector is calculated. An optical information reproducing method characterized in that the data in the unreadable sector is obtained by reproducing and reading the data.