JPH0963178A - Inspecting device of optical recording medium, method thereof and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase inspecting accuracy and to estimate the cause of generation of defect by recording data of previously set pattern and detecting/ displaying the generated portion of a bit error and defective size by comparing with the reproduced data. SOLUTION: Data of a previously set pattern are recorded on a recording surface 2 of an optical recording medium 1 by means of an optical head 5 of a bit error detecting means 4 and reproduced by the reflected light. Reproduced data are compared with the recorded data, the bit error of the optical recording medium 1 is detected and the signal is sent to a bit error portion calculating means 8 and defective size calculating means 9. The bit error generating portion and the defective size are calculated and a display screen is prepared by a plotter 11 through a corresponding position.size calculating means 10. A bit error generating position in common with plural optical recording media is calculated by means of a common defect detecting means 14. Consequently, highly accurate defect inspection is enabled, the defect is visually and easily recognized and early feedback to a manufacturing process is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus and an inspection method for an optical recording medium, and more particularly, to a defect in recording and reproducing functions of the optical recording medium with high accuracy and very easily recognizable. The present invention relates to an inspection apparatus and an inspection method for an optical recording medium, which can inspect information in a manufacturing process so that information can be fed back, and a method for manufacturing an optical recording medium using them.

[0002]

2. Description of the Related Art Conventionally, there has been a defect inspection device for detecting a defect on a recording surface of an optical recording medium by using an image processing device such as a CCD camera, but the resolution of the image input device is limited and the minimum detectable amount. The defect size was considerably larger than the actual defect size generated in the optical recording medium. Therefore, in order to detect defects with higher accuracy, it is necessary to separately provide a device dedicated to defect detection.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to detect defects in the recording and reproducing functions of an optical recording medium with unprecedentedly high precision, and to optically record the position, size, and shape of defects. By displaying information on the display screen corresponding to the recording surface of the medium so that it can be easily recognized at a glance, improving the inspection accuracy and extracting information for estimating the cause of defect occurrence from the inspection result, the manufacturing process Is to be able to provide feedback.

[0004]

In order to solve the above problems, an inspection apparatus for an optical recording medium of the present invention records data of a preset pattern on the optical recording medium, and reproduces the reproduced data and the recorded data. From a bit error detecting means for comparing patterns to detect a bit error, a bit error occurrence area calculating means for calculating an occurrence area of the bit error on the optical recording medium, and a spread or occurrence frequency of the bit error occurrence area. Defect size calculating means for calculating the defect size, the bit error occurrence area calculating means, and the calculation result of the defect size calculating means, the bit error occurrence area and the defect size are plotted on the display screen corresponding to the recording surface of the optical recording medium. And a defective portion / size display means for performing the same.

The optical recording medium inspection method according to the present invention is a bit for detecting a bit error by recording data of a preset pattern on the optical recording medium and comparing the reproduced data with the recorded data pattern. An error detection step, a bit error occurrence site calculation step for calculating the occurrence site of the bit error on the optical recording medium, and a defect size calculation step for calculating a defect size from the spread or occurrence frequency of the bit error occurrence site, And a defect site / size display step of plotting the site where the bit error has occurred and the defect size on the display screen corresponding to the recording surface of the optical recording medium from the calculation results of the bit error occurrence site calculation step and the defect size calculation step. The method is characterized by that.

Further, the method for manufacturing an optical recording medium according to the present invention comprises a method having an inspection step based on such an optical recording medium inspection method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an inspection apparatus for an optical recording medium according to an embodiment of the present invention. In the figure, 1 indicates an optical recording medium (for example, a phase change type optical recording medium), and 2 indicates a recording surface thereof. The optical recording medium 1 to be inspected is rotated at high speed by the drive device 3. Data of a preset pattern is recorded on the recording surface 2 of the rotating optical recording medium 1 by the laser light 6 from the optical head 5 of the bit error detecting means 4 and reproduced by the reflected light from the recording surface 2 (data reading). ) Is done. By comparing the pattern of the reproduced data with the pattern of the recorded data, occurrence of a bit error in the optical recording medium 1 is detected. For example, the presence / absence of occurrence of a bit error and the frequency of occurrence of the bit error may be detected for each sector, and the number of times of occurrence of the bit error (referred to as “occurrence frequency”) in a minute area of the unit area may be calculated. To detect this bit error, a bit error rate inspection device usually used in the optical disc inspection process can be used.

The signal from the bit error detecting means 4 is sent to the bit error occurrence portion calculating means 8 and the defect size calculating means 9 of the computer controller 7. The computer controller 7 is composed of, for example, a microcomputer, and the means described below is incorporated in the computer as a program. In the bit error occurrence portion calculating means 8, for example, the sector address of the recording surface 2 where the bit error occurred, and the radial position and reference position (for example, angle) on the recording surface where the bit error occurred from the bit error occurrence byte position in the sector. 0 °
Position) is calculated. That is, the information on the detected occurrence of the bit error is converted into the actual physical position information on the recording surface 2 by the sector address and the error occurrence byte information in the sector.

The defect size calculating means 9 calculates the defect size from the spatial spread of the detected bit error occurrence portion and the number of occurrences per unit area. This defect size may be calculated as an actual size, or may be calculated as the severity of the defect. When displaying a defect, it is better to calculate it to an exaggerated size with some amplification.
It is easy to visually recognize and inspect defects, which will be described later.

The signals from the bit error occurrence portion calculating means 8 and the defect size calculating means 9 are sent to the corresponding position / size calculating means 10. Corresponding position / size calculating means 10
Then, the optical recording medium 1 to be drawn by the plotter 11 described later
The actual position and size of the plot on the display screen (FIGS. 2 and 3) such as a plan view corresponding to the recording surface 2 of FIG. Therefore, based on this signal, the plotter 11 creates a display screen displaying defects as shown in FIGS.

By processing the signal of the corresponding position / size calculating means 10 by the enlarging means 12, the display screen drawn by the plotter 11 can be simply enlarged or can be partially cut and enlarged and displayed. These corresponding positions
Size calculating means 10, plotter 11 and enlarging means 12
Constitutes the defective portion / size display means 13 in the present invention. However, the enlarging means 12 may not be provided in particular. The display means 13 may be a hard copy device such as a plotter or a soft copy device such as a display device.

Further, in this embodiment, the common defect detecting means 14 is provided in the computer controller 7. When a plurality of optical recording media flow through the inspection process, the common defect detecting means 14 determines the bit error occurrence position common to the plurality of optical recording media based on the calculation result by the bit error occurrence part calculating means 8. . If the mode selected by the common defect detecting means 14 is selected,
The plotter 11 displays the bit error occurrence position common to the plurality of optical recording media.

In the inspection method and the optical recording medium manufacturing method using the optical recording medium inspection apparatus configured as described above, the unit is significantly smaller than that in the case of using the conventional image processing apparatus such as a CCD camera. Therefore, it is possible to inspect at bit size. Therefore, extremely accurate and accurate defect inspection is possible.

Further, since this inspection is carried out by comparing actually recorded and reproduced data, it is possible to measure the defect of the recording layer itself of the optical recording medium 1 and the defect of the track groove generated at the time of molding the substrate. In other words, even if the reflectance is constant, it is possible to measure defects in recording and reproduction due to other variation factors and defects. Alternatively, it is possible to measure even a recording / reproduction defect caused by a transfer defect of a microscopic track groove shape formed on the information recording surface side of the substrate. In addition, laser light power (recording power)
By changing, it is possible to measure the characteristics including the reflectance characteristics with high accuracy.

Further, since the defect information detected with high accuracy is drawn on the display screen corresponding to the recording surface 2 of the optical recording medium 1 by the plotter 11, the defect distribution can be visually (ie, at a glance) easily. I can confirm. For example, FIGS. 2 and 3
Examples 21 and 22 of the plan view in which the defect information is plotted are shown in FIG. 2, but in the example shown in FIG. 2, at a position near the outer periphery and at a position of about 90 ° to 240 ° from the reference position (0 ° position), Defects occur intermittently and intensively. In the example shown in FIG. 3, it can be seen that there are no defect concentration points, the bit error rate is uniform and small, and it is an excellent product with no practical problems. In this way, the occurrence status and distribution of defects can be confirmed at a glance.

Further, by the enlarging means 12, a certain portion, for example, an outer peripheral portion 23 of the plotted plan view 21 of FIG.
By enlarging and displaying as shown in FIG. 4, the distribution of defects becomes even clearer locally.

The defect occurrence information as shown in FIGS. 2 and 4 can be fed back to the manufacturing process of the optical recording medium.
For example, if the distribution of defects that have spread widely or the number of distributions of defect points shown in FIG. 3 increases abnormally, the film may peel during the manufacturing process, or dust may adhere during film formation or during handling. It is possible to estimate an increase in pinhole defects due to the above, etc., and if defects occur at the same location on multiple disks with the same stamper, it is possible to estimate that there is a defect in the stamper for molding the optical recording medium substrate. Becomes
Further, it adversely affects recording, for example, a hard coat layer,
Since it is possible to detect defects that occur in the coating layer of the overcoat layer, and also when the transport disc is scratched due to a defective handling jig, it is possible to provide appropriate feedback.

Further, since not only the distribution of defects but also the size thereof is displayed, for example, by displaying a state before, after, or in the middle of a wet heat test, the process of occurrence and growth of defects under wet heat conditions. It is also possible to grasp. For example, it is possible to narrow down the cause by chronologically tracking the defects due to the peeling of the adhesive at the interface of the recording layer, the progress of corrosion from the pinholes, and take appropriate measures.

Further, by using the mode of the common defect detecting means 14, the common defect data of a plurality of optical recording media can be extracted, and it is possible to determine which manufacturing process causes the defect. It becomes possible to grasp it accurately. For example, when defects occur at the same location on a plurality of optical recording medium discs made in series with the same stamper, it is possible to estimate that the stamper for molding the substrate of the optical recording medium has a defect.

Therefore, if the defect information corresponding to the recording surface of the optical recording medium 1 with high precision and accuracy as described above is known, it is possible to provide quick and appropriate feedback to the manufacturing process of the optical recording medium. Become. As a result, not only high-accuracy inspection but also appropriate processing of the manufacturing process for preventing defective products can be performed, which can contribute to manufacturing of higher quality optical recording medium and improvement of yield.

[0021]

As described above, according to the optical recording medium inspection apparatus, inspection method, and optical recording medium manufacturing method of the present invention, defects can be inspected with an unprecedentedly high precision, and The position, size, shape, and distribution of defects can be easily visually recognized, and defect analysis and early feedback to the optical recording medium manufacturing process can be easily performed. As a result, more reliable quality assurance can be achieved by higher inspection accuracy, and productivity can be improved by appropriate feedback to the manufacturing process.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical recording medium inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a recording surface of an optical recording medium showing an example of inspection results by the apparatus of FIG.

FIG. 3 is a plan view of a recording surface of an optical recording medium showing another inspection result by the apparatus of FIG.

FIG. 4 is a partial plan view in which a part of the plan view of FIG. 2 is enlarged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical recording medium 2 Recording surface 3 Drive device 4 Bit error detection means 5 Optical head 6 Laser light 7 Computer controller 8 Bit error occurrence site calculation means 9 Defect size calculation means 10 Corresponding position / size calculation means 11 Plotter 12 Enlargement means 13 Defects Part / size display means 14 Common defect detection means 21, 22 Plan view of recording surface as display screen

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Claims (5)

[Claims] 1. A bit error detecting means for detecting a bit error by recording data of a preset pattern on an optical recording medium, comparing reproduced data with the pattern of the recorded data, and an optical recording medium having the bit error. Bit error occurrence site calculation means for calculating the above occurrence site, defect size calculation means for calculating a defect size from the spread or occurrence frequency of the bit error occurrence site, the bit error occurrence site calculation means and the defect size calculation An optical-recording-medium inspection apparatus, comprising: a defective portion / size display means for plotting a portion where a bit error has occurred and a defective size on a display screen corresponding to the recording surface of the optical recording medium based on the calculation result of the means. 2. A common defect detecting means for deciding a bit error occurrence portion common to the plurality of optical recording media based on a calculation result by the bit error occurrence portion calculating means for a plurality of optical recording media. Optical recording medium inspection device. 3. The optical recording medium inspection apparatus according to claim 1, wherein the defective portion / size display means has a function of enlarging and displaying a part of a plot portion of the display screen. 4. A bit error detection step of recording data of a preset pattern on an optical recording medium, comparing the reproduced data and the pattern of the recorded data to detect a bit error, and an optical recording medium of the bit error. A bit error occurrence site calculation step for calculating the above occurrence site, a defect size calculation step for calculating a defect size from the spread or occurrence frequency of the bit error occurrence site, the bit error occurrence site calculation step and the defect size calculation A method for inspecting an optical recording medium, comprising: a defect site / size display step of plotting a site where a bit error has occurred and a defect size on a display screen corresponding to the recording surface of the optical recording medium based on the calculation result of the step. 5. A method of manufacturing an optical recording medium, which comprises an inspection step based on the method of inspecting an optical recording medium according to claim 4.