JPH03201229A - Optical disk checking device - Google Patents

Abstract

PURPOSE:To check defect every sectors by detecting the address of a sector of an information recording track and the effective range of the data part in the sector and detecting a defect in the data part in accordance with the change of the quantity of reflected light of irradiating laser light. CONSTITUTION:A sector detecting circuit 5 detects the leading part of each sector of an information recording track 3 based on an electric signal RF which an optical head 4 outputs in accordance with the quantity of reflected light. A sector address decoder 6 detects an address ADR of the sector by this sector detection pulse SF and the electric signal RF, and a data part detecting circuit 8 detects the effective range of the data part in the sector. A defect detecting circuit 7 detects a defect in the data part of the sector to update defect data DEF, and a write control circuit 9 outputs a write signal only at the time of detecting defective data to write the address ADR of the sector, where the defect exists, and defect data DEF in a memory part 10. Thus, defects of the optical disk are detected with one sector as the unit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical disk inspection device that optically detects defects in optical disks.

Conventional technology In recent years, optical discs have been developed as high-capacity recording media.

This optical disk records and reproduces information digitally using concentric circles or spiral tracks with pits formed by unevenness or magnetism. Since the information recording track of such an optical disk is minute, if there is a defect such as dust or damage, it becomes impossible to record or reproduce information, so it is necessary to inspect it to detect defects.

Therefore, as an apparatus for inspecting such an optical disk, there is one disclosed in Japanese Patent Application Laid-open No. 88347/1983. This detects the presence or absence of defects based on the light intensity level of the reflected light of the optical disk and the differential value of the light intensity, and consists of a predetermined number of information recording tracks set in advance based on the pulses output every time the optical disk rotates. Defect data is recorded for each block, and defects on the optical disc can be detected for each block, and the distribution density of defects in the radial direction of the optical disc can also be measured.

Problems to be Solved by the Invention Here, information recording and reproduction on an optical disc is actually performed for each sector obtained by dividing the information recording track of the optical disc in the circumferential direction.1 For example, when recording information in a sector, When an error occurs, that sector is considered to be defective, and information is recorded in a replacement sector. Here, a specific sector is often secured in advance as the sector for replacement, and if a defect exists in the sector secured for replacement, there is a high possibility that the defect will occur again, which is not preferable. Further, if a long defect such as a burst exists in a sector, it is impossible to reproduce information at all. because of these reasons,
Detection of defects on an optical disc must be performed for each sector.

However, in the above-mentioned optical disk inspection apparatus, since defect detection is performed for each block consisting of a predetermined number of information recording tracks, it is not possible to specify a sector having a defect due to insufficient data.

Means for Solving the Problem An optical head that irradiates the information recording track of an optical disk with a laser beam and outputs an electric signal according to the amount of reflected light is placed opposite the optical disk, and the information recording track is determined from the electric signal output by the optical head. A sector detection circuit is provided to detect the beginning of each sector, and a sector address decoder is provided to detect the address of the sector from the output signal of the sector detection circuit and the optical head. Defect detection includes a data section detection circuit that detects the effective range, detects a defect in the data section of a sector from the output signal of the data section detection circuit and the optical head, and updates defect data in accordance with the content of the detected defect. A write control circuit is provided which outputs a write signal from the outputs of the defect detection circuit and the data part detection circuit only when defective data exists in the data part of the sector. A memory section is provided in which the address of a sector in which a defect exists and defective data are written in the sector data section according to the output of a signal from the output of the defect detection circuit.

The optical head that irradiates the information recording track of the optical disk with a laser beam outputs an electrical signal according to the amount of reflected light, and the sector detection circuit into which the electrical signal output from this optical head is input detects the beginning of each sector of the information recording track. The sector address decoder to which this sector detection circuit and the output signal of the optical head are input detects the sector address.
The data part detection circuit to which the output signal of the sector detection circuit is input detects the valid range of the data part in the sector, and this data part detection circuit and the defect detection circuit to which the output signal of the optical head is input detects the valid range of the data part of the sector. The write control circuit, to which the output signals of the defect detection circuit and the data section detection circuit are input, detects the defect in the sector and updates the defect data in accordance with the contents of the detected defect. A write signal is output only when there is a defect, and in accordance with the output of the write signal of this write control circuit, the address and defect data of the sector in which the defect exists is written in the memory section from the output of the defect detection circuit to the sector data section. By doing this, defects on the optical disc are recorded along with the contents for each sector address.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 3. First, the optical disk inspection apparatus 1 of this embodiment is provided with an optical head 4 capable of focusing, tracking, etc. at a position facing the rotatably supported optical disk 2 and the information recording track 3. The output section of 4 is a sector detection circuit 5 and a sector address decoder 6.
and the defect detection circuit 7. The output section of the sector detection circuit 5 is connected to the sector address decoder 6 and the data section detection circuit 8, and the output section of the data section detection circuit 8 is connected to the defect detection circuit 7 and the write control circuit 9. It is connected. Here, the output section of the defect detection circuit 7 is also connected to the input section of the write control circuit 9, and the output section of the write control circuit 9, the sector address decoder 6, and the defect detection circuit 7 are connected to each other. It is connected to a memory section IO, and the output section of this memory section 10 is connected to a totalizer 11.

Incidentally, each sector 12 of the information recording track 3 of the optical disk 2 to be inspected by this optical disk inspection apparatus 1 includes a sector mark 13, a synchronization section 14, an address section 15, a synchronization section 16, and data, as illustrated in FIG. The structure is such that the portions 17 are sequentially formed.

With such a configuration, in this optical disk inspection apparatus l, the optical head 4 that irradiates the information recording track 3 of the rotating optical disk 2 with a laser beam outputs an electric signal according to the amount of reflected light, and this electric signal R, F is input to the sector detection circuit 5, sector address decoder 6, and defect detection circuit 7. Therefore, the sector detection circuit 5 detects the sector mark 13 present at the beginning of each sector 12 of the information recording track 3 based on the electric signal RF and outputs a sector detection pulse SF. The sector address decoder 6 to which the electric signal RF is input reads the address part 15 of the sector 12 and outputs the address ADR.

Further, the data section detection circuit 8 to which the sector detection pulse SF is input detects the effective range of the data section 17 following the address section 15 within the sector 12, and the optical head 4 is located within the effective range of this data section 17. The data section valid signal D is
E is valid. Then, the defect detection circuit 7 to which the data section valid signal DE and the electric signal RF are input clears the previous defect data as the data section valid signal DE becomes valid, and then clears the defective data in advance. Defects in the data portion 17 of the sector 12 are detected based on known techniques such as changes, and when detected, counters such as the length and number of defects are updated, and the defect data DEF is output. The defect detection signal DF is made valid. Note that this defect detection signal DF becomes invalid at the same time as the data section valid signal DE becomes invalid.

Then, this defect detection signal DF and data section valid signal DE
The write control circuit 9 to which is input the data section 1 of the sector 12 because both of them have changed from valid to invalid.
It is detected that a defect exists in 7 and outputs a write signal WR. The address AD output from the sector address decoder 6 and the defect detection circuit 7 according to the output of the write signal WR.
R and defect data DEF are written into the memory section 10.

Note that memory section 1 of address ADH and defect data DEF
The address signal indicating the storage location within 0 is updated every time the write signal WR is output.

The address AD written in the memory section 10 in this way
With R and the defect data DEF, defects on the optical disc 2 are recorded together with the contents for each address of each sector 12.

Furthermore, in this optical disk inspection apparatus 1, the memory section 10
The contents stored therein are read out by a totalizer 11, and the defective data is totaled for each zone consisting of a predetermined number of sectors.

This is in response to the fact that replacement of defective sectors on the optical disk 2 is often performed within a zone consisting of a preset number of sectors, and by doing this, data regarding defects on the optical disk 2 can be more easily read. It can be obtained in any useful form.

Further, by setting the counting method of the tallying unit 11 to be changeable, even if the setting of the alternate processing zone of the optical disc 2 is changed, it can be easily handled.

Effects of the Invention As described above, the present invention enables the optical head that irradiates the information recording track of an optical disk with a laser beam to output an electric signal according to the amount of reflected light, and detects the sector into which the electric signal output from the optical head is input. The circuit detects the beginning of each sector of the information recording track, and the sector address decoder, into which the output signal of this sector detection circuit and the optical head is input, detects the address of the sector, and the output signal of the sector detection circuit is input. The data part detection circuit detects the valid range of the data part in the sector, and the defect detection circuit to which this data part detection circuit and the output signal of the optical head are input detects a defect in the data part of the sector and detects the content of the defect. The corresponding defect data is updated, and the write control circuit to which the output signals of the defect detection circuit and the data section detection circuit are input outputs a write signal only when defective data exists in the data section of the sector. The address and defect data of the sector in which the defect exists is written in the memory part from the output signal of the defect detection circuit to the sector data part according to the output of the write signal of the write control circuit, so that the defect of the optical disk is detected in the sector. It is recorded along with the address, and defects are detected for each sector of the optical disk. Therefore, it is possible to check the defect status of special sectors used for replacement processing (replacement sectors), extract sectors with many bursts, etc.
It is possible to check defects for each sector, and by aggregating the above defect data for each zone for replacement processing, it is also possible to check for defects in accordance with replacement processing.Furthermore, the aggregation method can be changed freely. This has the advantage of being able to quickly respond even when the replacement processing zone is changed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a conceptual explanatory diagram showing the contents of sectors, and FIG. 3 is a time chart. l... Optical disc inspection device, 2... Optical disc, 3
...Information recording track, 4...Optical head, 5...
・Sector detection circuit, 6... sector address decoder,
7... Defect detection circuit, 8... Data part detection circuit, 9
...Write control circuit, 10...Memory section, 12...
Sector, 17...data section

Claims (1)

[Claims] An optical head that irradiates an information recording track of an optical disk with a laser beam and outputs an electrical signal according to the amount of reflected light, and a sector detection that detects the beginning of each sector of the information recording track from the electrical signal output by the optical head. a sector address decoder that detects the address of the sector from the output signal of the sector detection circuit and the optical head; and a data part detection circuit that detects the effective range of the data part in the sector from the output signal of the sector detection circuit. a defect detection circuit that detects a defect in the data section of the sector from the output signal of the data section detection circuit and the optical head and updates defect data corresponding to the content of the defect; a write control circuit that outputs a write signal from the output of the data portion detection circuit only when the defective data exists in the data portion of the sector; An optical disk inspection device comprising an address decoder and a memory section into which the address of a sector in which a defect exists and defective data are written based on the output signal of the defect detection circuit.