JPH0373440A - Defect inspecting device of disk-shaped information recording medium - Google Patents

Abstract

PURPOSE:To necessitate one time of the reproduction for the puprose of detecting defects by combining and handling the discretely detected defects of one bit to a defect lump in accordance with the position information thereof, detecting the kinds of the defects or defect lump and storing the information of the kinds, positions and sizes of the defects and defect lumps. CONSTITUTION:This device has a section 3 for detecting the information on defect sizes, a section 5 for detecting control track errors, a section 6 for detecting the generation of an address decoding gate signal and a header error, a section 7 for detecting the kind of the defects, a section 9 for detecting the information on the track position, a section 10 for detecting the information on the angle and sector position, and a memory 11. The defects are detected by the reproduction signal obtd. by reproducing the information recording medium to be inspected by a reproducing device 2. The kind, diametral position and circumferential position thereof are detected simultaneously therewith. The defects approaching in accordance with the detection positions thereof are combined as the defect lump and the sizes in the diametral and circumferential directions thereof are calculated. Further, the kinds, positions and sizes of these defects and defect lump are stored. The inspection by using a microscope is executed by using these stored contents. The inspection of the defects by one time of reproduction is enabled in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a defect inspection device for disc-shaped information recording media such as optical discs, magnetic discs, and magneto-optical discs.

[Background Art and Problems to be Solved by the Invention] In a disc-shaped information recording medium such as an optical disc, signals are recorded on tracks formed in a spiral or concentric circle. For this reason, unlike magnetic tape, where signals are recorded in a straight line,
Widespread defects, or burst defects, may occur that span multiple adjacent tracks.

FIG. 9 shows a disk-shaped information recording medium and its burst defect state. In this example, tracks are formed in a spiral shape on the disk-shaped information recording medium 51, and there are defects 52a over five tracks and defects 52b over two tracks. When a reproduced signal is obtained from such a disk-shaped information recording medium, seven dropout pulses P1 to P7 are detected as shown in FIG.

Detecting dropout pulses only detects the number of individual defects on the tracks of a disc-shaped information recording medium, and it is difficult to determine whether or not there are so-called burst defects.
Further, the 6 positions etc. cannot be detected. For this reason, in the past, burst defects were often detected by visual inspection by a worker using, for example, a microscope.

For the purpose of detecting such burst defects, the invention disclosed in Japanese Patent Publication No. 63-27779, for example, has been proposed.

The invention disclosed in Japanese Patent Publication No. 63-27779 is constructed as shown in the circuit diagram of FIG. 11, and the signal states of each part are as shown in the timing chart of FIG. 12.

In the figure, 53 is an input terminal for the reproduction signal from the disk-shaped information recording medium, and the dropout pulse a as shown in FIG. 12(A) includes the dropout pulse as shown in FIG. 10 above. ing. This dropout pulse a is input to the flip-flop 54.

The flip-flop 54 enters a set state as shown in FIG. 12(B) by receiving the dropout pulse a from the input terminal 53, and its output signal becomes high level.

When the flip-flop 54 is set and its high level output signal is input, the counter 55 counts the chronographs CL input from the terminal 56, and the result is a predetermined number, specifically a drop clock. When the count reaches a number corresponding to a time slightly shorter than the time from when the first out-pulse a is generated until the disk rotates once, a counting end signal is output. By receiving this count end signal, the monostable multi-by-by-break 57 is triggered and outputs a rotational position pulse d of a predetermined width as shown in FIG. 12(D). This rotational position pulse d is applied to a flip-flop 58 and a monostable multivibrator 59.

When the rotational position pulse d is applied, the monostable multi-bye-bye break 59 outputs a pulse C as shown in FIG. 12(C), which is applied to reset the flip-flop 54. As a result, the flip-flop 54 is reset as shown in FIG. 12(B), and the counter 55
counting is stopped. Note that the pulse C output by the monostable multi-bye-bye break 59 is also given to the counter 60.

When the dropout pulse a'' is again input to the input terminal 53 while the rotational position pulse d output from the monostable multi-vibrator 57 is at a high level, the flip-flop 54 is set again and the counter 55 starts counting. The flip-flop 58 is set in synchronization with the fall of the output pulse d of the monostable multi-bye-bye break 57, and a signal e as shown in FIG. 12(E) is output. Its state is determined by the signal d, and if the signal d is at a high level when the signal d falls, it is in the cent state, and if the signal d is at a low level when the signal d falls, it is in the reset state.

When the dropout disappears when the disk rotates three times after the first dropout, the output pulse C of the monostable multivibrator 59 causes the flip-flop 54 to
remains in the reset state for 41 seconds, and the flip-flop 58 is reset by the fall of the signal d and the low level of the signal S. When the flip-flop 58 falls, the monostable multivibrator 61 outputs a drone knob out completion signal f as shown in FIG. 12(F).

As described above, the output pulse C of the monostable multivibrator 59 is input to the counter 60. A counter 60 counts the number of output pulses C, ie, the number of consecutive tracks with dropouts. The count value of the counter 60 is the gate circuit 6
given to 6. The output signal of monostable multivibrator 61 is given to gate circuit 66 as a trigger signal.

With such a configuration, when the dropout winter end signal f is output, the number of consecutive trunks with dropouts is output from the gate circuit 66.

In this embodiment, gate circuit 66 outputs the degree of the number, rather than the number of consecutive trunks themselves. The gate circuit 66 classifies numbers into three levels, and terminals 66a,
A signal is output from 66b or 66c.

The dropout end signal r is provided to the counter 60 via a delay circuit 68 as a reset signal.

In this way, in the invention of Japanese Patent Publication No. 63-27779, the rotational position pulse d is generated by the occurrence of dropout,
Correspondingly, if a dropout pulse a is present, the presence of a so-called burst defect, in which a series of defects are clustered together in the radial direction of the disk, is detected.

However, in the invention of Japanese Patent Publication No. 63-27779 mentioned above,
If multiple defects exist on the same track at certain intervals, the circuit with the above configuration can only detect one defect on the same trunk, so prepare multiple sets of circuits or Alternatively, it may be necessary to perform multiple tests by slightly shifting the timing of dropout detection. Furthermore, the size of the burst, that is, the length in the circumferential direction of the disc-shaped information recording medium cannot be detected.

Japanese Patent Application Laid-Open No. 64-72087 proposes a method for determining and inspecting the position of dropouts on a magnetic disk.

This method determines the dropout angle (circumferential position) and radial position, stores these positions, and controls the position of the magnetic disk facing inspection equipment such as a microscope based on this stored position information. do.

However, with this method, even if there is a burst defect, the position of the magnetic disk must be controlled for each unit dropout (one bit of data), resulting in poor inspection efficiency.

Furthermore, defects include physical defects and data defects, and since these types are related to processing after defect detection, it is necessary to identify and store them, but the above two publications do not meet such requirements. No corresponding technology has been disclosed.

The following is the recording format of the optical disc according to ISO standard 5.
The 25-inch one will be explained.

Tracks are formed on the disk-shaped information recording medium 51 in a spiral or concentric manner. As shown in Figure 12, PEP (Phase
Encode Part) Control Toranoku 5
18.

5FP (Standard Format Part)
Control toranoku 51B, SFP user area 5
1C, SFP control track roll trunk records data such as recording/reproducing conditions for data signals on the disc-shaped information recording medium 51, and
The P user area 51C is used by the user to record arbitrary data.

Further, in the disc-shaped information recording medium 51, trunks other than the PEP control trunk 51A are radially partitioned to form °C sectors. Each sector has a header section 5 in which track and sector addresses are recorded.
It is composed of 0A and a data section 50B for recording data. However, SFP Control Torasoku 518,
As described above, various data of the disc-shaped information recording medium 51 are recorded in the data section 50B of the SFP 510.
The data portion 50B of the user area 51C is a portion for the user to record data, and is in an unrecorded state during inspection at the factory.

Note that a flag section 50C is formed at the beginning of the data section 50B of the SFP user area 51C.

In the disk-shaped information recording medium 51 having such a format, the types of defects and the inspection methods differ in each part. For example, since the data portion 50B of the SFP user area 51C is unrecorded, there can be no data defects here, only physical defects.

In contrast, the header section 50 of the SFP user area 51C
In A, both types of defects can occur, and in the case of data defects, the inspection contents are different, so it is necessary to identify the type of defect to which area it belongs. Therefore, conventionally, the SFP user area consists of a header section 50A and a data section 50B.
and are present alternately over the entire circumference, it was decided that the inspection of only the header section 50A over all the tracks and the inspection of only the data section 50B thereof would be performed twice. Therefore, there was a problem that the inspection efficiency was low.

The present invention has been developed to solve these problems, and it handles individually detected 1-bit defects as defect clusters based on their position information, and also handles defects or defect clusters. To detect the type of defect, to store information on the type, position, and size of the defect mass, only one replay is required for defect detection, and it is easy to handle in subsequent microscopic inspections. The purpose of the present invention is to provide a defect inspection device for information recording media.

[Means to solve the problem]

In order to achieve such an object, the defect inspection apparatus of the present invention includes a means for detecting a defect using a reproduced signal from a disc-shaped information recording medium, a means for detecting the type of detected defect, and a means for detecting a defect by using a reproduction signal from a disc-shaped information recording medium. means for detecting the radial position and circumferential position of the defect; means for dividing the defect into defect masses based on the detected position; means for calculating the radial dimension and circumferential dimension of the defect mass; and means for storing the type, position and size of the defect or defect mass.

[Effect]

A reproduction signal is obtained by applying the information recording medium to be inspected to a reproduction device. Defects are detected using the reproduced signal, and their type, radial position, and circumferential position are also detected.Next, based on these detected positions, the approaching defects are grouped together as defect clusters, and their radial direction 1 Calculate the circumferential dimension.7.These defects.

The type, position, and size of the defective lump are memorized. Examination using a microscope is performed using this memory content.

〔Example〕

The present invention will be described in detail below based on drawings showing embodiments of an optical disc.

FIG. 1 is a block diagram showing the overall configuration of the device 1 of the present invention (shown surrounded by a broken line). An optical disk (not shown) to be inspected is loaded into a playback device (optical disk drive) 2, and the analog playback signal obtained thereby is sent to a defect size information detection section 3 and an A/D (analog/digital) converter 4. is input to.

The defect size information detection unit 3 detects the size of the defect and provides it to the defect type detection unit 7. ^/D converter 4 converts the input analog reproduction No. 43 into digital (No.
and is input to the address decoding/gate 1ε signal generation/header error detection unit 6.

The control track error detection section 5 detects errors included in the control data recorded in the entire PEP control trunk 51A and the data section 50B of the SFP control tracks 51B and 510, and provides the result to the defect type detection section 7.

The address decoding/gate signal generation/header error detection unit 6 decodes the address signal reproduced from the header part 50A of each of the SFP control tracks 51B, 51D and the SFF' user area 51C included in the reproduced data and detects the area on the track. and outputs the results to the trunk position information detection unit 9 and the angle/sector position information detection unit 10, and also generates a gate signal for each information recording area being reproduced and outputs it to the defect type detection unit 7. do. It is also output to the angular sector position ↑a information detection unit 10.

The address decoding/gate signal generation/ladder error detection unit 6 also detects errors (header errors) included in the data recorded in each header section 50A, and sends the results to the defect type detection unit 7. give.

The defect type detection section 7 includes the defect size detection section 3. Control tracker: Detects information regarding the size and type of the defect from the defect detection result and data No. to be memorized.

The reproducing device 2 outputs one rotation pulse for each rotation of the optical disk, and this pulse is input to the angle/sector position information detection section 10 and the track position information detection section 9. The track position information detecting section 9 detects information regarding a track in which a defect or error exists from this rotation pulse and the address decoding result given from the address decoding/gate signal generation/header error detecting section 6, and stores it in the memory 11.

The angle/sector position information detection section 10 detects a reference position on the disk-shaped information recording medium where a defect or error exists based on the rotation pulse and the result of attrition/sector decoding given from the address decoding/gate signal generation/header error detection section 6. detects information about the angle and sector from;
It is stored in the memory 11.

The memory 11 is the defect 1-1 type detection unit 7 described above. Track position information detection unit 9 and angle/sector position information detection unit 10
Detection results are stored.

Computer 8 is a defect stored in memory 11.

x for reading out error data and detecting defective lumps, which will be described later, and for inspecting the optical disc to be detected using a microscope.
-Controls the position of the y stage, etc.

The above defect size detection section 3. A/D converter4. Control track error detection section 5. Address decoding/gate signal generation/header error detection section 6゜Defect type detection section 7.
Track position information detection section 9. Angle/sector position information detection section 10. The memory 11 and the computer 8 constitute the missing knot detection device of the present invention.

Each part will be explained in detail below. First, defect size information detection section 3
I will explain about it.

FIG. 2 is an enlarged schematic diagram of a burst defect existing on a disk-shaped information recording medium.

In the figure, the center of rotation of the disk 20 is at the bottom, and the outer edge is at the top. A large number of trunks T are formed on this disk 20, and FIG. 2 shows an 11th trunk Tll as an example.
-21st track T21 is shown.

21 is a burst defect, which extends from the 13th track T13 to the 20th track T20 of the disk 20 in this example. Therefore, the number of cross trunks is 8. The center of the track is the 17th trunk T17.

Now, for example, the 20th tiger number T2 is played by the playback device 2.
If 0 is reproduced, the circumferential length information of the defective portion indicated by hunting in the figure is obtained from the defect size information detection unit 3. The defect size information detection section 3 detects a signal caused by a defect contained in the reproduced signal to obtain a track ant pulse, and uses a dropout pulse generation circuit 3a and a counter to count the length of each dropout pulse as a clock number. 31).

The counted value of the counter 3b is given as bits 0.1, 2 to A, B to the selector 7a (FIG. 3) of the defect type detection section 7 as information representing the circumferential length of the defect.

Figure 4 shows the data format (a) for one sector of the SFP user area 51C, the data 1-signal, and the error signal (
b) to (h) are illustrated. A gate generating section (FIG. 8) of the address decoding/gate generating/header error detecting section 6 generates various gate signals from this input.

FIG. 4('b) shows control tracks 51B, 510
This is a gate signal of "L" during reproduction of the SFP user area 51C. This gate signal is applied to selectors 7a, 7b, and 7c of the defect type detection section 7 shown in FIG. The hesoda gate shown in FIG. 4(C) becomes "H" while the header area is being reproduced, and this is input as the defect type detecting section 7 as a defective signal 1-F. The flag gate shown in FIG. 4 (fd) is at the "I2" level only at the beginning of the data area. This gate signal is given as a signal E to the defect type detection section 7. Figures 4(e) and 4(f) show data errors in the control track and 5YNC and RESY of the data area in the control track.
It indicates the presence or absence of an NC error, and remains at "L" if there are no errors as shown in the figure. These signals are outputted from the control track area data detection section 5, and error signals are given as D and C to the defect type detection section 7.

If there is a defect in the data area in the SFP user area 51C, defective signals 0 and 1 are generated in the flag area at that timing as shown in FIG. 5 (gl).
．． 2...If there are A and B, a pulse appears at the same timing as shown in FIG. 5 fhl. These dimension information are input to the defect type detection section 7 as bits 0 to B as described above.

FIG. 5 shows another error occurrence situation. Check the CRC (CyclicR) at the parity check area PA in the Noda area.
When a signal representing an error in edudue Ch, eck) is obtained, a pulse representing a CRCI, CRC2, CRC3 or serial error is obtained and is applied to bits 3 and 21.0 of the defect type detection section 7, respectively. This error in the header area is detected by the address decoding/gate signal generation/header error detection section 6 of the header error detection section.

FIG. 6 is a timing chart when there is a data error in the control track. The control gate signal is at a high level as shown in FIG. 6(b). The control track error detection unit 5 detects an error in the SFP comptoir track 51B or 51D and outputs a signal as shown in FIG. 6 (el).
This is applied to bit D of the defect type detection section 7. If there is a defect in the flag area (Figure 6 (h)), the position is shown by the solid line, and if there is a defect in the data area (Figure 6 (g)).
)) is 2 points tM! It becomes high level at the position shown.

Figure 7 is the same < 5YN of SFP control track
A time chart is shown when there is an error in CRESYNC. In this case 5YNC and/or RESYNC
This is the same as in FIG. 6 except that a high level signal appears in the region.

FIG. 8 is a block diagram showing the configuration of the gate generating section of the address decoding/gate signal generating section/header error detecting section 6. As shown in FIG. The digital playback data output from the A/D converter 4 is applied to the sector mark (SM) detection section 6a and address mark (AM) detection section 6b of this gate generation section, and the sector mark detection section 6a is applied to the SFP user areas 51C and SFP.
If the sector mark in the FP control area 51B, 51D cannot be obtained or there is an abnormality, an error signal is generated. This is set to bit 0 by selector 7b as shown in FIGS. 3 and 5.
given to.

When the SM detection unit 6a detects the sector counter 55M, it resets the sector counter 6c and starts clock counting (not shown). The count value is input to the gate generation section 6d, and the gate generation section 6d outputs a header gate signal and a flag gate signal according to the count value. The output data No. 113 is given to the selector 6e.

On the other hand, the address mark output by the address mark detection section 6b is input to the address demodulation section 6f, where address data is obtained and given to the defect type detection section 7. Further, the address is checked in the CRC check section 6)i. As a result of the check, if an error exists, the CI? C
An error signal (CRCI, 2.3) is output and given to the defect type detection section 7. The gate generating unit 6g checks from the address mark whether it is the control area 51B, 51D or the 1-the area 51C, and in the case of the former, H
”, and this is manually inputted to the defect type detection section 7 via the selector 6e.The selector 6e indicates whether the optical disk to be detected is formatted or not (unformatted). A signal is applied to select and output a hesoda gate signal, a flag gate signal, and a control trunk gate signal.

The defect type detection section 7 outputs 16-bit defect size/type data based on inputs from the defect size detection section 3, the control trunk error detection section 5, and the address decoding/gate generation/header error detection section 6. This 16-bit data is stored in the memory 11 together with 16-bit data representing angles and sectors from the angle/sector position information detection section 10 and 16-bit data representing tracks from the track position information detection section 9.

FIG. 9 shows an example of this stored data. Figure 9 (a
l shows an example of an unformanted disk with a defect in the SFP user area 51C, and as mentioned above, the LSB side is 0,
1.2...The defect size data is entered in 12 bits of A and B, and the 4 pins C, D, E, and F on the MSB side are all O.

Figure 9 (bl is the data when there is a defect in the SFP flag area of the format disk, and the 4-bit data on the MSB side is "0100". In other words, the flag gate is "H" for this defect. This is because

Figure 9 (C1 shows the case where there is an SFP header error, the 4 bits on the MSB side become “1000” and the 4 bits on the LSB side
The bits 0, 1, 2, and 3 become "1" in accordance with each of the SM error, CRCI, and 2.3 error. The middle 8 bits are meaningless in this error case, and the second 16 bits are the sector, not the angle.

FIG. 9(d) shows a data error in the control track, and in this case, the 4 bits on the MSB side are "0010". Also, in Figure 9 (e+ is a 5YNC, RFSYliC error, the MSB side 4 bits are “0001” and 5Y
The difference between IJC error and) IEsYNc error is LSB side 2
Identified by bits. In these cases as well, the data in other parts of the first 16 bits is meaningless.

FIG. 10 organizes the codes of the above-mentioned four bits on the MSB side and the bits on the LSB side.

Next, data processing by the computer 8 will be explained. 11th. Figure i2 shows memory 1 as described above.
1 is a flowchart showing a processing procedure for determining a defect type when defect size/type data stored in Embodiment 1 is read out.

First, the computer 8 reads the defect data and sequentially examines the dimension data portion starting from the MSB side as shown in FIG. If the F bit is 1', processing proceeds to the header error subroutine (Figure 12), and the F bit is set to "O".
If the C-th bit is “1”, it is determined that there is a flag area defect, and the E-th bit is “0” and the D-th bit is “1”.
If so, it is determined that there is a control trunk data error, and if the D bit is “0” and the C bit is “0#”, it is determined that there is a user area defect or an unformatted disk defect, and the C bit is If it is “1” and the Oth bit is “1”, it is determined that there is a 5YNC error, and if the Oth bit is “01” and the first bit is “11”, it is determined that there is a RESYNC error.
It is determined to be an error.

In the header error subroutine, if the Oth bit is "1", it is determined to be a 5M error, and if the Oth bit is "0" and the first bit is "1", it is determined to be a cRci error; If the bit is “0” and the second bit is “1”, it is determined that there is a CRC2 error, and the second bit is “O”.
If the third bit is "1", it is determined that there is a CRC3 error.

The computer 8 determines the type of defect from the defect data as described above.

Next, a procedure for classifying defect data into defect chunks will be explained. FIG. 13 is a flowchart of the main routine, and FIGS. 14-17 are flowcharts of the subroutines.

The memory 11 stores defect size and type data as described above. FIG. 18 shows an example of this stored information, showing its size (SIZE), track number (TRACK), and angle (ANGLE). Pick up is the line number,
CLASS is available in three sizes, S and M, depending on the size.

Denoted as L (all M here), R is the distance from the center of the trunk. The computer 8 reads out such data, first sorts the defective data in descending track order (from the largest value to the smallest value), and then initializes the parameter ■ to "1" (steps St and S).
2). ■ is the number of sorted defect data. FIG. 19 is a list of data after sorting.

If (1) is the number of the trunk where the first defective data exists, then N+13- (I) being "O" means that other defective data exists on the same trunk.

"-l" means that defective data exists in the adjacent track. If it is less than "-2", it means that defective data exists on discontinuous tracks, that is, there are two defects in at least one trunk separated by N.

Therefore, in step S3, (1+i)-(1) is calculated and defects are classified (steps S3.S4.S5.S6).

The computer 8 determines that the result of step S3 is "0" or "-"
1", count the number of times in step 57゜S.
8) If the value is "-2" or less, a continuous defect has been detected in steps S5 to S8, so the center track number is stored (step 9).

In Figure 19, when I=1, (1+1)-(1)17
133 -18411 ≦-2, and (1) =18411 track defects are regarded as defects on discontinuous tracks.

! If = 2, then 17132-17133 = -1 Therefore, it is considered a defect on a continuous track.

This state continues until I=20.

When 1=21, 11954-17114≦-2, so the 22nd defect is considered to be a defect in a track that is discontinuous with the previous ones. The second to first defects are recognized as one defect cluster. Step S9
In this case, the center of the 2nd to 21st trunks is 11 or 12.
It is requested and memorized as such.

Similarly, defects in the 22nd and 23rd tracks are also recognized as defect clusters.

Note that in this example, there is no defect corresponding to (I+1)-(1)=0.

The computer 8 performs the above processing on all defect data while incrementing the parameter I by "1".
(Stenbu SIO, 5ll).

Next, the computer 8 initializes the parameter J to "11" (step 512), and determines whether the track (J) (Jth trunk) is the center of continuous defects or not in the step S described above.
Judgment is made according to the data stored in step 9 (step S
13〉. If "YIES", the process of the burst defect subroutine (step 515) shown in FIG. 14 is executed, and if "No", the process proceeds directly to step 7 515.

The burst defect subroutine is the 14th burst defect subroutine, which will be detailed later.
The process is as shown in the flowchart of the figure, and simply involves detecting the upper and lower limits of consecutive defect tracks, the central trunk, and the number of consecutive defects indicating the range in which tracks having defective data are continuous. The computer 8 executes this process while incrementing the parameter J by "1" (step 516), and when finished, executes the defect isolation subroutine (step 517).

This defect separation subroutine is shown in a flowchart in FIG. 15 and will be described in detail later, but it is simply a process of separating defects on the same track based on the angle in the circumferential direction of the disc-shaped information recording medium. In other words, when a plurality of defects exist on the same track, it is detected whether they constitute one burst defect or are separated defects depending on the angle from the reference position of the disk-shaped information recording medium.

When the computer 8 finishes processing the defect separation subroutine in step S17, it outputs the result to, for example, a CRT display or a printer (step S18).
).

FIG. 14 is a detailed flowchart of the burst defect subroutine.

First, the computer 8 initializes the parameter M to J in step S20>, and CM+1)-CM) is "-2".
The parameter M is incremented by "l" until it becomes smaller (step 522), CM+1)-CM
] is smaller than "-2' (step 521), the track with track number [M] is set as the lower limit of continuous defective tracks, that is, the innermost track (step S23).

This process sequentially checks track numbers starting from the center of a continuous defect, that is, a defective mass, and if the track numbers are two or more apart, it is determined that this is the end of the defective mass. For defect clusters 2 to 21, for example, if M = J = 12, M is incremented in order from (13) - (12) = 17122 - 17123 (22) - (21
)=11954-17114≦-2, M=21 is set as the innermost track of this defective mass.

Similarly, the computer 8 initializes the parameter L to J (step 524), and increments the parameter L by "1" until (L-1)-(L) becomes greater than "2" (step 526). ), (L-1)-(L)
If becomes larger than "2" (step 525), the trunk of track number (L) is set as the upper limit of consecutive defective tracks, that is, the trunk at the outer circumference of the defective mass (step 527).

Finally, the computer 8 stores the upper and lower limits and the center track of the consecutive defective trunk, and also calculates and stores the number of consecutive tracks using the upper and lower limit values (step S2
8).

In the example in Figure 19, the calculation is performed from L=12 and when L=2, (1) - (2) = 18411-1713
Since 3≧2, the L=second trunk is set as the outermost track.

FIG. 15 is a flowchart of the defect isolation subroutine.

First, the computer 8 initializes the parameter K to "1" (step 531) and detects the first burst defect (defect lump).
The data of each trunk is stored (step 532), and the angle subroutine is executed (step 533).

The flowchart of the angle subroutine is shown in FIG. 16 and will be described later, but in short, it determines whether multiple defects on the same track constitute one burst defect or not.
Or, it is a routine for determining whether the defects are separated from each other.

Through the processing of the angle subroutine in step S33, it becomes clear whether the multiple defects on the same trunk are a group of burst defects or different burst defects, so the computer 8 increments the parameter K by "l". , after performing the above-described processing for each burst defect (step 535), the process returns.

FIG. 16 is a flowchart of the angle subroutine.

First, the computer 8 sorts the defects in the same defect cluster, that is, in descending order of the angle (ANGLε) of the th burst defect (step 540). FIG. 20 shows the results of sorting in descending order of angle.

Next, initialize the parameter N to “1”.

Step 541), the angle (N) of the defect number N in the burst defect to be processed in step S32 of the defect separation subroutine is (N) - [N+ 1) 50.3'
, the number of defects is counted as continuous in the circumferential direction of the disc-shaped information recording medium.Step S42.5
43), if (M)-(M+1) is greater than 0.3'', it is assumed that the defect with number N and the defect with number N+1 are different, and the process of the burst data subroutine (step 544) is executed. In the example shown in Figure 7R20, there are no two defective masses in the circumferential direction.

The computer 8 executes the above process while incrementing the parameter N by "1" until the parameter N reaches the number of burst defects (step S45.546), and returns when the parameter N reaches the number of burst defects.

FIG. 17 is a flowchart of the burst data subroutine. In this subroutine, the computer 8 stores the angular center, trunk center, and maximum width dimension of the burst data, and then returns. Angle center 1
The width direction dimension is calculated based on the counting result in step S43, and the computer 8 detects a burst defect based on the data stored in the memory 11.

FIG. 21 shows the results of burst defect inspection by the apparatus of the present invention, and is a schematic diagram showing the disc-shaped information recording medium (optical disk) to be inspected and the burst defects present on its information recording surface. This is a list of burst defects that can be obtained.

"*" in Fig. 21 indicates a burst defect, the numbers indicate sector numbers, rsIZE (max) J in Fig. 22 indicates the maximum dimension in the width direction of the burst defect, r TRACK (c
enter) sets the trunk center of the burst defect center to rT! ? ACK(cross) J is the number of trunks crossed by the burst defect, rANGLE(center) −
, 1 is the angle of the center of the burst defect using the same criteria as above,
rRJ indicates the distance from the center.

〔Effect of the invention〕

According to the method of the present invention as described above, defects can be inspected by one reproduction. Furthermore, it is possible to combine a large number of 1-bit defects into a defect cluster. Furthermore, since the size and position of the missing M mass are memorized, subsequent inspection using a microscope, etc. can be performed efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of the device of the present invention, and FIG.
The figure is a schematic diagram of a burst defect, Figure 3 is a block diagram of the main part of the defect type detection section, Figures 4 to 7 are timing charts of gate signals, and Figure 8 is a pro-7 of the gate signal generation section. Figure 9 is a format diagram of defect size type data, Part 1
Figure 0 is a code diagram of the defect type, Figure 1L12 is a flowchart for flame type determination, Figure 13 is a flowchart showing the processor J+ji for classification into defect clusters, Figure 14 is a flowchart for burst defect navigating, and Figure 15 is a flowchart for the burst defect navigator. A flowchart of the defect separation subroutine, FIG. 16 is a flowchart of the angle subroutine, FIG. 17 is a flowchart of the burst data subroutine, FIGS. 18 to 20 are defect data list diagrams, and FIG. 21 is a schematic diagram showing an example of inspection results. Fig. 22 is a list diagram showing the data, Fig. 23 is a schematic diagram showing a disc-shaped information recording medium and burst defects existing on it, Fig. 24 is a waveform diagram showing a dropout pulse, and Fig. 25 is a conventional FIG. 26 is a timing chart for explaining its operation, and FIG. 27 is a configuration diagram of an information recording area of an ISO standard optical disc. 3... Defect size information detection unit 5... Control [
- Rack error detection section 6... Address decoding/gate generation/header error detection section 7... Defect type detection section 8... Computer 9... Track position detection section 10... Angle/sector position information detection Part 11...
・Memory In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] (1) means for detecting a defect using a reproduction signal from a disc-shaped information recording medium; means for detecting the type of the detected defect; and means for detecting the radial position and circumferential position of the detected defect. , means for dividing defects into defect clusters based on detected positions; means for calculating radial and circumferential dimensions of defect clusters; and means for storing types, positions, and dimensions of detected defects or defect clusters. A defect inspection device for a disc-shaped information recording medium, comprising: