JPS62109246A - Inspection device for disc for information recording - Google Patents

Abstract

PURPOSE:To apply the defect inspection of an information recording disc such as an optical disc in a short time and for the entire recording area by using a 2-dimensional sensor as a sensor detecting a defect. CONSTITUTION:An object to be inspected 1 is fitted to a spindle 2 and driven. Then a controller 11 is activated to oppose the 2-dimensional sensor 5 to the optional region of the object 1 to be inspected. In irradiating a light 4a for the inspection to the object 1 to be inspected via a half mirror 3 via a light source 4, the light is reflected in a recording film 1a and made incident on the 2-dimensional sensor 5 via the half mirror 3. In switching a shutter provided between the half mirror 3 and the sensor 5, the reflected light at each phase of the object 1 is made incident on the 2-dimensional sensor 5 continuously, an analog signal in response to the incident light intensity is digitized and recorded sequentially in a data memory 7. Then a data from a normal pattern generator 8 is read, the pattern matching processing of both data is applied in a CPU 9 to discriminate the presence of a defect.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to systems typified by video discs and the like using a laser method or a capacitance method. 11 iQ This invention relates to an inspection device for Q discs.

[Conventional technology]

This type of information recording disc is, as shown in Figure 2,
A reproduction laser beam 22 focused by a focusing lens 21 is irradiated onto the recording film forming surface 20 of an information recording disk, and a signal is generated by utilizing changes in the reflected laser beam intensity between pits 23 and areas without pits 23. This is because it reads out the .

If there is a defect such as a scratch or a protrusion on the recording film forming surface 20, a problem occurs in that an erroneous signal is directly read out.

The above description has been made of an information recording disc on which pre-pits are formed, but even for information recording discs on which pre-groups are formed, if there is a defect on the recording film forming surface 20, tracking failure may occur and accurate information reading may not be possible. A similar problem occurs, such as being blocked. Furthermore, although the above describes problems during signal reproduction of information recording discs on which pre-pits, pre-groups, or both are formed, in information recording discs that can be written on immediately, there are problems not only during reproduction, but also during reproduction. During recording, a problem arises in that information signals or tracking (No. 6) cannot be accurately recorded.

Conventionally, in order to prevent the supply of such defective products, inspections have been conducted to discover such defects before the products are shipped.

The conventional defect inspection method is to first check for visible defects by visual inspection, and then apply a special defect inspection liquid to the test pieces for which no defects were found by visual inspection to optically detect the defects. FIG. 3 is a perspective view showing an example of a conventionally used defect inspection machine of this type, in which a two-step inspection method is adopted in which the inspection object 30 is rotated. A driving spindle 31, a laser head 32 that irradiates the inspection laser beam 1132a onto the object 30, a tracking servo system 33 that tracks the laser head 32, and a sensor 34 that detects the reflected beam from the object 30. The sensor 3
By sending the output signal from 4 to the host computer 35, it is possible to judge whether there is a defect or not and to perform statistical processing on the defect (reference is unknown).

The conventional inspection apparatus described above drives a spindle 31 and a tracking servo system 33 to send a laser beam 32 along pit examples or groups of a test object 30, and a sensor 34 detects a beam reflected from a recording film. By detecting changes in the intensity of the recording film, it is possible to know whether there are defects formed on the recording film. Therefore, by moving the laser head 32 from the 0-track 0-sector of the test object 30 to the last sector of the last trunk, the entire recording area of the test object 30 can be inspected for defects.

However, since this inspection apparatus is configured to send the laser head 32 along a pit row or group of the object 30 to be inspected, it has the disadvantage that inspection takes a long time. For example, in the case of a 12-inch information recording disc,
Approximately 90 minutes of inspection time is required to inspect the entire recording area, and it is impossible to inspect the entire recording area of all products on an actual manufacturing line.

Conventionally, in order to shorten the inspection time, a so-called sampling inspection has been carried out, in which only a previously sampled area of the recording area of the test object 30 is inspected.

[Problems with conventional technology]

Sampling inspections are based on statistical theory, so it is naturally impossible to completely check for defects, and a certain percentage of defective products will be supplied to the market. When a large number of defective products are supplied to the market, not only does it require a great deal of expense and effort to back them up, but it also causes serious consequences such as a loss of consumer trust in the manufacturer and a decline in competitiveness in the market. It may also lead to

In addition, conventional inspection equipment has an arithmetic unit for determining the presence or absence of defects and for performing Synopsis 1 processing regarding defects.
Since the host computer 35 performs several processes and calculations, it takes a long time to transfer data to the host computer 35 and wait for commands from the host computer 35. There is a problem in that the inspection time is correspondingly longer and the inspection efficiency is poor.

From this point of view, it is possible to completely inspect all recording areas of all products for defects in a short period of time! Side A is promising.

[Means for solving problems]

In order to solve the above problems, the present invention includes: a light source that irradiates a test object with inspection light; a two-dimensional sensor that is placed opposite the test object and detects reflected light from the test object; A data memory that stores the output signal from the two-dimensional sensor as two-dimensional data corresponding to the radial and circumferential directions of the object to be inspected, and a pattern of reflected light intensity possessed by a defect-free information recording disk? - Judging the presence or absence of a defect and performing processing related to the defect according to the generated normal pattern generator and the steps stored in the program memory based on the data from the data memory and the normal pattern generator. It is characterized by being equipped with a device.

[Implementation row]

FIG. 1 is a block diagram of an information recording disk inspection apparatus showing one embodiment of the present invention, in which 1 indicates an object to be inspected;
2 is a spindle for rotationally driving the test object 1;

3 is a semi-transparent mirror, 4 is a semi-transparent mirror 3, and 8 membrane 1 of the specimen 1 is inspected through the semi-transparent mirror 3.
a is a light source that irradiates inspection light; 5 is a two-dimensional sensor that detects the reflected light from the recording film 1a of the object l through the semi-transparent mirror 3; and 6 is an analog signal from the two-dimensional sensor 5. An A/D converter that converts the data into an 8-bit digital signal, 7 a data memory with a two-dimensional configuration for recording the I/O signal from the A/D converter 6, and 8 a defect-free information recording disk. A normal pattern generator 9 generates a pattern of reflected light intensity, and a central processing unit 9 performs judgment on the presence or absence of defects and statistical processing of defects based on the data from the data memory 7 and the normal pattern generator 8. C.P.
U), LO is a program memory in which programs for judgment and processing performed by the CPU 9 are stored, and 11 is a C
A controller that adjusts the position of the two-dimensional sensor 5 based on the test results of uF2, L2 a drive device that drives the two-dimensional sensor 5, and 13 a display device that displays the test results of the CP[J9. .

The spindle 2 is connected to a drive motor (not shown), and rotates the test object 1 fixed by the fixed JL2a at a constant speed.

The semi-transparent m3 means that the inspection light 4a from the light g4 is transmitted to at least the two-dimensional sensor 5, which will be described in detail later, in the recording area of the test object 1.
It is placed on the recording film 1a side of the object 1 so that the recording area to be detected is irradiated with uniform intensity.

As the two-dimensional sensor 5, an image pickup tube such as a photoelectric type image pickup tube or a light guide type image pickup tube, or a charge coupled device (CC) is used.
Any known two-dimensional sensor can be used, such as a solid-state imaging device in which solid-state imaging devices such as D) or a packet brigade device (BBD) are arranged two-dimensionally. The type of two-dimensional sensor to be used among these two-dimensional sensors 5 is appropriately selected depending on the purpose and object of the inspection.

Normal pattern occurrence 1r! 8 consists of a memory with a two-dimensional configuration, in which pits and groups identical to those of the test object 1 are formed, and the unique reflected light intensity pattern of an information recording disk with no defects is preliminarily recorded as a digital signal. Based on the program stored in the program memory 10 (according to instructions from the CPU 9), it is read out as appropriate.

The CPU 9 performs pattern matching processing on the data from the data memory 7 and the data from the normal pattern generator 8 according to the program stored in the memory 10 of the progera 11, and determines whether or not there is a defect depending on whether or not the two data are the same. and its size, and according to the pass/fail criteria stored in advance in the program memory 10, the test object 1 is inspected.
Determine whether or not the product is appropriate. Further, the shape, size distribution, etc. of defects are statistically processed according to a program stored in advance in the program memory IO.

As the display device 13, any known device such as a CRT or a liquid crystal display device can be used. Note that a printer may be attached instead of the display device] 3 or together with the display device 13.

Hereinafter, a method for inspecting defects on information recording discs using the inspection apparatus of the above embodiment will be described.

First, the test object 1 is mounted on the spindle 2, and the drive motor (not shown) is immediately activated to rotate the test object 1's [! move.

At the same time, the controller 11 is operated to cause the two-dimensional sensor 5 to face any eFiW of the object l.

Next, when the inspection light 4a is irradiated from the light source 4 to the object to be inspected through the semi-transparent ff13, the inspection light 4a illuminates the film 1.
Reflected at a, semi-transparent! The light is input to the two-dimensional sensor 5 via t3. At this time, if a shutter (not shown) provided between the semi-transparent mirror 3 and the two-dimensional sensor 5 is opened and closed at the required timing, the reflected light at each phase of the object l is continuously transmitted to the two-dimensional sensor 5. can be incident on the target.

In the two-dimensional sensor 5, the incident light is converted into a two-dimensional electric analog No. 41 corresponding to the intensity of the incident light, and output from the output terminal. The analog signal is sent to the A/D converter 6 and converted into a corresponding 8-bit digital signal 71, which is sequentially stored in the data memory 7.

Next, data from the data memory 7 and data from the normal pattern generation ri8 are read out according to the program stored in the program memory 10.
In this step, pattern matching processing is performed on both data. Through this, the presence or absence of a defect in the test object 1 is determined,
The results are displayed on the display device 13. Furthermore, if it is determined that there is a defect, it is determined whether the degree of the defect is within predetermined product standards, and the result is displayed on the display waveform 13. be displayed on. In addition to these judgments, the shape, size, distribution, etc. of the defect are statistically processed by the CPU 9.

When the inspection of one recording area is completed as described above, the drive device J
12 is driven, and the two-dimensional sensor 5 is transferred to a predetermined area.

Hereinafter, the above procedure f: by repeating the operation sequentially.

Is it possible to check the entire recording area for defects?

In the case of the inspection apparatus of the above embodiment, it is possible to detect defect information in the entire recording area by rotating the object to be inspected several times. Complete the defect inspection of the older varnish area of the two test objects. In addition, normal Hatern generator 8, CI) U
9. Performance consisting of program memory lO w'ixV! 1
, half-transparent mirror 3. Since it is integrally attached to the detection section consisting of the light source 4, two-dimensional sensor 5, A/D converter 6, and data memory 7, data transmission time is short and defect inspection can be performed quickly.

In the above embodiment, the two-dimensional sensor 5 capable of inspecting a part of the object 1, the light g4, and the semi-transparent mirror 3 are used to sequentially inspect the object 1 by rotating the object 1. Although a case has been described in which the entire object to be inspected is inspected, the gist of the present invention is not limited thereto. It is also possible to make it possible to perform inspection at a specific time. In this case, a spindle for rotationally driving the test object 1 and a controller I for driving the two-dimensional sensor 5 are used.
Of course, the I and the drive device 12 are no longer necessary.

[Effects of the Invention] As explained above, since the information recording device according to the present invention uses a two-dimensional sensor as a sensor for detecting defects, it can be used for information recording on optical discs etc. We want to be able to inspect disks for defects in a short period of time and on the entire recording area.

Therefore, the information recording day (all areas of the screen) can be inspected by UJ.
In addition, the reliability of information recording discs can be significantly improved compared to the conventional sampling inspection method.In addition, it is possible to determine the presence or absence of defects in information recording discs and to perform statistical processing of defects. Since the arithmetic bag Vl for performing the test is integrally provided, the test time can be significantly reduced compared to when the test is performed online to a host computer.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of the defect checking device according to the present invention, Fig. 2 is a cross-sectional view showing the principle of reproducing information on an information recording disk, and Fig. 3 is a block diagram showing an example of the defect checking device according to the present invention. It is a block diagram showing an example of a defect inspection device. 1: object to be coated, 2 varnish spindle, 3: semi-transparent mirror, 4: solo source, 5: two-dimensional sensor, 6: -A, /D converter, 7; f-
8: Normal pattern generator. 9: CPU, 10 Niprogram memory, 11: Controller, 12: Drive? jJ neck, 13: Display device F': 1.
゛- Attorney's Attorney 7 A. Part 1: 1:'
i,,,-' Fig. 18. Each 9 for normal patterning: CPIJ 10 Program memory 11 Controller 12 Drive device 13 Display ζ1 Fig. 2 Fig. 3 35

Claims (1)

[Claims] A light source that irradiates the test object with inspection light, a two-dimensional sensor placed opposite to the test object that detects the intensity of reflected light from the test object, and an output signal from the two-dimensional sensor that detects the diameter of the test object. a data memory for storing two-dimensional data corresponding to the direction and the circumferential direction; a normal pattern generator for generating a pattern of reflected light intensity of a defect-free information recording disk; 1. An information recording disk inspection device comprising an arithmetic unit that determines the presence or absence of defects and performs statistical processing regarding defects according to procedures stored in a program memory based on data.