JPH06251529A - Optical disk inspection device - Google Patents

Abstract

PURPOSE:To obtain a disk inspection device which can easily detect the defective position of an optical disk (magneto-optical disk). CONSTITUTION:A rotation driving means (spindle motor) 2 rotating the optical disk 1 and an optical pickup 4 irradiating the disk 1 with a laser beam and detecting the state of reflected light are provided. Besides, a discrimination means 8 discriminating the defect of the disk 1 based on the output of the pickup 4, position detection means 6, 8 and 13 detecting a position where the disk 1 is irradiated with the laser beam from the pickup 4 and a memory 10 storing the information of the defect of the disk 1 are provided. Then, when the defect of the disk 1 is detected by the discrimination means 8, the positions of the disk detected by the detection means 6, 8 and 13 are stored in the memory 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc inspection apparatus for inspecting an optical disc such as an optical disc or a magneto-optical disc on which data is optically recorded or reproduced.

[0002]

2. Description of the Related Art An optical disc in which data is optically recorded or reproduced by using a laser beam has a signal recording surface or a disc surface in a predetermined state (for example, whether it is smooth or not) when the disc is manufactured. Is it being inspected? By discriminating that a disc determined to have a defective portion by such an inspection is not shipped as a defective product, only non-defective products will appear as products and troubles due to the use of defective products can be prevented.

[0003]

By the way, since the conventional inspection apparatus of this type merely detects whether or not there is a defective portion on the disk, it is difficult to perform a detailed analysis of the defective state of the disk. It was not possible to know which position on the disc was bad. For this reason, even if there is a cause of a defect in the original plate used for molding the optical disk, it is difficult to identify the cause of the defect because the defect location cannot be identified.

In view of the above points, the present invention has an object to provide a disc inspection apparatus of this type which can easily detect a defective position of an optical disc.

[0005]

SUMMARY OF THE INVENTION The present invention is, for example, as shown in FIG. 1, an optical disc inspection apparatus for detecting the state of an optical disc 1 on which recording or reproduction is performed optically. 2, an optical pickup 4 for irradiating the optical disc 1 with a laser beam to detect the state of reflected light, a discriminating means 8 for discriminating a defect of the optical disc 1 from the output of the optical pickup 4, and a laser beam from the optical pickup 4. When the discriminating means 8 detects a defect of the optical disc 1, the position detection means 6, 8, 13 for detecting the position of the optical disc 1 irradiated with the optical disc 1 and the memory 10 for storing the defect information of the optical disc 1 are detected. The disk positions detected by the means 6, 8 and 13 are stored in the memory 10.

In this case, the discriminating means discriminates the smoothness of the surface of the optical disk.

Further, in this case, the defect information and the position information are divided into a lower bit and an upper bit and stored in the memory.

[0008]

According to the present invention, when the defect of the optical disk is detected, the information of the detected position at this time is stored in the memory, so that the defective position can be specified from the information stored in the memory.

Further, in this case, by discriminating the smoothness of the surface of the optical disc as a defect detection, the disc, which is particularly problematic when the surface smoothness is poor such as a magneto-optical disc, can be satisfactorily inspected.

Further, in this case, the defect information and the position information are divided into the upper bits and the lower bits and stored in the memory, so that the data can be efficiently stored in the memory.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a configuration of an optical disc inspection apparatus of this example. In FIG. 1, reference numeral 1 denotes an optical disc as an object to be inspected. Here, the optical disc 1 is a magneto-optical device for recording data on a magnetic film by laser light. Use a disc. The optical disc 1 is inspected for defects and is rotated by a spindle motor 2. In this case, the encoder 3 is attached to the rotary shaft of the spindle motor 2,
The encoder 3 outputs a pulse every time the spindle motor 2 rotates by a predetermined angle (for example, 10 °).

A laser light source such as a semiconductor laser;
The laser light output from this laser light source is used for the optical disc 1
An optical pickup 4 having a built-in optical member such as a lens for irradiating the optical disk and a photosensor for receiving the laser beam reflected by the optical disk 1 is arranged near the optical disk 1. The rough position of the laser beam applied to the optical disc 1 from the optical pickup 4 in the radial direction of the disc changes as it is driven by the sled motor 5. The sled motor 5 is driven based on command data output from the motor control circuit 6. That is, the command data output from the motor control circuit 6 is converted into a control voltage by the data conversion circuit 7, and the sled motor 5 is driven to a position based on the value of this control voltage. Fine adjustment of the laser beam applied to the optical disc 1 in the radial direction of the disc is performed by moving the objective lens in the optical pickup 4.

A signal processing circuit 8 is connected to the optical pickup 4. The signal processing circuit 8 processes the signal detected from the disc and the laser light emitted from the optical pickup 4 is transmitted to the disc. Various servo controls are made to follow the upper track. Further, in connection with this servo control, data on the amount of movement of the objective lens in the optical pickup 4 is supplied to the signal processing circuit 8.

Then, the signal processing circuit 8 processes the signal detected from the disc, and supplies the data showing the characteristic of the processed optical disc to the defect discriminating circuit 9. The data indicating the characteristics of the optical disc include, for example, a detected RF signal and a servo error signal. Then, the defect discriminating circuit 9 discriminates whether or not the disc has a defective portion based on the data showing these characteristics. For example,
The smoothness of the surface of the optical disk is discriminated from changes in the RF signal and the servo error signal, and when a state with poor smoothness is detected, the location with poor smoothness is determined as a defective location. Then, when it is determined that there is a defective portion, the characteristic data (data relating to smoothness or the like) at this time is supplied to the memory 10 as digitized data. The memory 10 stores the data of the defective portion of the disk, and stores the position data of the defective portion of the disk described later together with the data of the characteristic of the defective portion.

Further, the data of the moving amount of the objective lens (data of the moving amount of the disk in the radial direction) supplied to the signal processing circuit 8 is supplied to the analog / digital converter 11, and this analog / digital converter 11 is supplied. The digital data converted by the above is supplied to the adder 12. Further, the sled motor command data output from the motor control circuit 6 is supplied to the adder 12, and the sled motor command data and the objective lens movement amount data are added by the adder 12 to the disk 1. Data of the radial position on the disk of the laser light to be irradiated is obtained, and the data of the radial position on the disk is supplied to the memory 10.

The output of the encoder 3 that outputs a pulse each time the spindle motor 2 rotates by a predetermined angle is supplied to the counter 13, and the counter 13 counts the number of pulses. At this time, the count by the counter 13 resets the count value every one rotation. Therefore, the count value matches the rotation angle of the rotation shaft of the spindle motor 2. Then, the count data output by the counter 13 is supplied to the memory 10.

On the memory 10 side, when the characteristic data of the defective portion is supplied from the defect judging circuit 9, the data of the radial position on the disk supplied from the adder 12 side at the same time and the counter 13 are supplied. The output count data (rotation angle data) is stored. As the storage state at this time, the data of the radial position on the disk and the rotation angle data are stored as a high-order bit, and the data of the characteristic of the defective portion is stored as a series of data that is a low-order bit.

A display device 14 is connected to the memory 10 so that the data relating to the defective portion stored in the memory 10 at a predetermined time can be displayed with numerical values such as the radial position and the rotation angle position together with the defective state. There is.

According to the optical disc inspection apparatus having the above-described structure, when the optical disc 1 has a defect, the data of the state (characteristic) of the defective portion is stored in the memory 10 as the lower bit and the data of the characteristic is stored. The data of the radial position and the rotation angle position are stored in the upper bits of.
Therefore, by observing the display of the data stored in the memory 10 on the display device 14, if the inspected disc has a defect, its position can be specified, and the defective state of the disc can be directly checked or the disc can be checked. It becomes possible to easily check the relevant part on the molding machine side and investigate the cause of the defect.

In the above-mentioned embodiment, the portion of the disc surface having poor smoothness is inspected, but the state of another disc may be inspected. For example, partial eccentricity of the track formed on the disk, a defective portion of the coating, or the like may be inspected. In addition, a plurality of items may be inspected at the same time.

Further, in the above-mentioned embodiment, the magneto-optical disk in which data is recorded on the magnetic film by the laser beam is inspected, but another optical disk inspection apparatus in which data is optically recorded or reproduced. Of course, it can also be applied to.

[0023]

According to the present invention, when a defect of an optical disk is detected, the information of the detected position at this time is stored in the memory, so that the defect position can be specified from the information stored in the memory, and the defect is detected. It becomes possible to easily analyze the defective state of the disk based on the determination of the position.

Further, in this case, by discriminating the smoothness of the surface of the optical disc as the defect detection, it is possible to satisfactorily perform the inspection of the disc which is particularly problematic when the smoothness of the surface is bad like the magneto-optical disc.

Further, in this case, the defect information and the position information are divided into upper bits and lower bits and stored in the memory, so that the data can be efficiently stored in the memory.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

[Explanation of reference numerals] 1 optical disc 2 spindle motor 3 encoder 4 optical pickup 5 thread motor 6 motor control circuit 8 signal processing circuit 9 defect determination circuit 10 memory 13 counter 14 display device

Claims (3)

[Claims] 1. An optical disc inspection apparatus for detecting the state of an optical disc on which recording or reproduction is performed optically, and a rotation driving means for rotating the optical disc, and irradiating the optical disc with laser light to detect the state of reflected light. Optical pickup, discriminating means for discriminating a defect of the optical disc from the output of the optical pickup, position detecting means for detecting a position where the laser beam from the optical pickup is irradiated on the optical disc, and defect information of the optical disc. And a memory that stores, when the discriminating means detects a defect in the optical disc,
An optical disc inspection device for storing the disc position detected by the position detection means in the memory. 2. The optical disc inspection apparatus according to claim 1, wherein the discriminating means discriminates the smoothness of the surface of the optical disc. 3. The optical disk inspection device according to claim 1, wherein the defect information and the position information are divided into a lower bit and an upper bit and stored in the memory.