JP2000011468A - Method of inspecting optical disk protective coat and inspecting device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of inspecting an optical disk protective coat which automatically distinguishes the presence or absence of 'coat irregularity' of the protective coat of an optical disk 1, and to provide an inspecting device using the method. SOLUTION: A protective coat of an optical disk 1 and a reflecting coat are irradiated with light beam (s) containing a shadow of a fixed form pattern by an illumination means 5 covered with a net like body of the fixed form pattern in front of a light source, and a picture of the reflected light (t) containing the shadow of the fixed form pattern projected on the protective coat of the optical disk 1 and the reflecting coat is taken by a photographing means 4. And, in a reference optical disk 1 having a normal protective coat, the shadow of the fixed form pattern is taken beforehand by the photographing device 4, and the shadow image is used as an reference image. And, at inspection, a shadow of the fixed form pattern in photographed on the optical disk to be inspected 1, and compared with the reference image by an image recognition means 8, and the presence or absence of 'coat irregularity' is judged by a discrimination means 9 by recognizing deformed conditions of the fixed form pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for inspecting "coat unevenness" of a protective coating film for protecting the surface of a vapor-deposited film on an optical disk such as a compact disk (hereinafter referred to as a CD).

[0002]

2. Description of the Related Art An optical disc is produced through a process in which aluminum is deposited as a reflective film on a molded signal forming surface, and a protective coating material is applied to the upper surface of the optical disk to prevent oxidation of the reflective film. That is common. As a method of applying a protective coating material, a so-called "spin coating method" is often used, and an example thereof can be found in JP-A-4-195744. As another method, there is a method in which an orifice for discharging a protective coating solution in a band shape corresponding to the coating width is arranged, and a coating film having a substantially constant thickness is obtained by simply rotating the disk once. And conventionally,
Most of the methods for determining whether such a protective coating material is applied uniformly are visual inspections. In general, it is normal that the protective coat film is applied uniformly, but sometimes the protective coat film may have wavy irregularities, which is not called “coat unevenness”. It is determined to be good.

On the surface of a compact disk (hereinafter referred to as "CD") or the like, a maker name, a song name, a player name, etc. are printed on this protective coat film in order to display the recorded content recorded on the CD. ing. CD printing refers to printing ink on this protective coat film. At the stage of print inspection, a “non-printed state” where no print is made on the protective coat film and a case where it is printed on the protective coat film Can be divided into “printing states”. If "coat unevenness" has occurred, "coat unevenness" under "printing status"
By visually inspecting the prints, the prints may be uneven due to the influence of the coated surface, and as a result, the prints may be visually observed as “print unevenness”. However, in the “non-printed state”, it is very difficult to visually check the “coat unevenness” of the protective coat film because the protective coat material is translucent and the underlying vapor deposition surface is a mirror surface.

In general, when inspecting the state of the printing surface, a printing surface inspection device is used. In the printing surface inspection device, uniform illumination is usually applied to the entire surface of the CD. With such uniform illumination, a subtle change in unevenness on the coated surface cannot be accurately recognized due to reflection of light by a mirror surface.

[0005]

SUMMARY OF THE INVENTION The present invention automatically discriminates the state of application of a protective coating material on an optical disk without using the above-described visual inspection. An object of the present invention is to provide a method for inspecting a protective coat film, which can accurately detect the presence or absence of “coat unevenness” even in a coat film, and an inspection apparatus using the same.

[0006]

According to the method for inspecting a protective coat film of the present invention, a shadow of a fixed pattern is projected on a reflective film of an optical disc, and the shadow is imaged, and the protective coat film formed on the reflective film is formed. The surface state of the protective coating film is inspected by detecting the deformation of the shading of the lattice pattern caused by the above.

In another method for inspecting a protective coat film according to the present invention, a light beam including a shadow of a fixed pattern is irradiated onto a reflective film of an optical disk at a predetermined incident angle, and the light having a shadow of the fixed pattern is irradiated. By imaging the reflected light from the reflective film, by detecting the deformation of the shading of the fixed pattern, which is caused by the wavy irregularities on the surface of the protective coat film formed on the reflective film,
The presence or absence of a wavy uneven shape on the surface of the protective coat film is determined.

According to still another method for inspecting a protective coat film of the present invention, a light beam including a shadow of a fixed pattern from directly above on a reflective film of an optical disk is provided in comparison with the above-described method for inspecting a protective coat film. Irradiates the reflected light from the reflective film including the shadow of the fixed pattern, and detects the deformation of the fixed pattern shadow caused by the wavy irregularities on the surface of the protective coat film formed on the reflective film. By doing so, the presence or absence of a wavy uneven shape on the surface of the protective coat film is determined.

Further, the protective coating film inspection apparatus of the present invention has a light source whose front surface is covered with a net-like body having a fixed pattern, and the light source uses the fixed light to face the reflective film of the optical disk at a predetermined incident angle. Illuminating means for irradiating a light beam (s) including a shadow of the pattern; and reflected light (t) including a shadow of the fixed pattern of the mesh projected on the reflective film and the protective coat film formed on the reflective film. Image processing means for processing the shadow image of the fixed pattern captured by the imaging means, and an image recognition means for recognizing the presence or absence of deformation of the shadow of the fixed pattern of the shadow image; and a detection result of the image recognition means. Determining means for determining the presence or absence of a wavy uneven shape on the surface of the protective coating film of the optical disk based on the determination.

In another embodiment of the protective coat film inspection apparatus according to the present invention, an optical disk, a half mirror, and an image pickup means are arranged coaxially with an axis of the optical disk in this order. A light source whose front surface is covered with a mesh of a standard pattern, including a shadow of the standard pattern at an incident angle of 45 degrees toward the half mirror surface. An illuminating means for irradiating a light beam (x); and a light beam (x) having a 45-degree inclination with respect to the axis of the optical disk and containing a shadow of the fixed pattern emitted from the illuminating means. A half mirror that reflects the light downward toward the reflection film, and reflected light (y) including the shadow of the fixed pattern reflected from the reflection film and the protective coat film formed on the reflection film passes through the half mirror. Imaging hand An image recognition unit that processes the image captured by the imaging unit and recognizes whether or not the shading of the fixed pattern is deformed by the net-like body; and a protection coat for the optical disk based on a detection result of the image recognition unit. Determining means for determining the presence or absence of a wavy uneven shape on the film surface.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment (●) of an inspection apparatus using the protective coating film inspection method of the present invention will be described with reference to the drawings. FIG. 1 is a schematic explanatory view showing a main configuration of a protective coat film inspection apparatus 10 according to the present embodiment, and a reflection film 10 of an optical disc 1 such as a CD mounted on a turntable 2.
1 is to inspect the applied state of the protective coating material (102) applied on the surface 1. That is, it is normal that the coating material is uniformly applied, and depending on the application method and the like,
Irregularities may be formed on the surface of the protective coating material, which is called “coat unevenness” and is determined to be defective. (See FIG. 2) Reference numeral 5 denotes an illuminating unit for irradiating the optical disk 1, which is installed so as to irradiate the optical disk 1 with incident light at a predetermined incident angle. The illuminating means 5 is provided with a light source 6 for generating uniform parallel light, and a reticulated body 7 having a fixed pattern (grating, dots, etc.) covering the front surface of the light source 6 (removably attached so as to cover the light source 6). ). The illuminating means 5 is installed at a position where the incident light (s) can be irradiated at a predetermined angle of incidence from obliquely upward toward the optical disk 1, and the above-mentioned fixed pattern is formed on the reflection film and the protective coating film of the optical disk 1. The incident light (s) including a shadow is irradiated, and the shadow of the fixed pattern is projected on the reflective film and the protective coat film.

Reference numeral 4 denotes imaging means such as a CCD camera or the like at a position where the reflected light (t) including the shadow of the fixed pattern projected on the reflection film and the protective coating film can be imaged from a diagonally upper side at a predetermined reflection angle. is set up.

Reference numeral 8 denotes an image recognizing unit which processes the captured image captured by the image capturing unit 4 and recognizes whether or not the shading image of the fixed pattern is deformed.

Numeral 9 denotes a judging means for judging whether or not "coat unevenness" exists in the protective coat film of the optical disk based on the recognition result of the image recognizing means 8.

FIG. 2 is a cross-sectional view showing the structure of the optical disc 1 to which the present embodiment is applied. The signal forming surface of the transparent molded substrate 100 onto which the digitized signal is transferred is shown in FIG.
In order to reflect a laser beam for signal reproduction emitted from below in the figure, a reflection film 101 made of an aluminum vapor deposition film is formed. Reference numeral 102 denotes a protective coating film for preventing the reflection film 101 from being oxidized. FIG. 2 shows a case in which the protective coating film is formed by a spin coating method, which is a method of forming the protective coating film. 2 spreads to the periphery of the disk due to centrifugal force, as shown in FIG. 2, a wave whose wavelength increases toward the periphery is generated, and when cured as it is, the protective film 102 with wavy irregularities remaining on the surface is formed. Become.

The operation of the embodiment (●) will be described. (A) As shown in FIG. 1, the illumination means 5 irradiates incident light (s) including a shadow of a fixed pattern on the protective coat film and the reflective film of the optical disc 1. (B) The imaging means 4 images the reflected light (t) including the shadow of the fixed pattern projected on the protective coating film and the reflection film of the optical disc 1. (FIG. 3 shows a shaded image of a standard pattern (lattice pattern) of a CD having “coat unevenness” (part A).) (C) In advance, a normal protective coat film (“coat unevenness”)
Without. ), A shadow of a fixed pattern is imaged, and the shadow image is used as a reference image. (D) At the time of inspection, on the optical disk 1 to be inspected, a shadow of the fixed pattern is imaged, the shadow image is compared with the reference image, and the degree of deformation of the fixed pattern is recognized to thereby determine “coat unevenness”. Is determined.

Another embodiment (●) of the inspection apparatus using the protective coat film inspection method of the present invention will be described with reference to the drawings.

FIG. 4 is a schematic explanatory view showing a main configuration of the protective coat film inspection apparatus 10 according to the present embodiment. Reference numeral 1 denotes an optical disk placed on the inspection table 2.

The positional relationship among the optical disk 1, the half mirror 3, the image pickup device 4, and the illuminating means 5 is arranged at predetermined intervals so that the center axes of the optical disk 1, the half mirror 3, and the image pickup device 4 are aligned in this order. Has been established. The central axis of the illuminating means 5 is orthogonal to the central axes of the optical disk 1, the half mirror 3, and the imaging device 4.
Is incident at an incident angle of 45 degrees.

The half mirror 3 is disposed above the optical disc 1 at an angle of 45 degrees with respect to the axis of the optical disc 1.

The illuminating means 5 comprises a light source 6 for generating uniform parallel light, and a mesh having a fixed pattern (gratings, dots, etc.) attached so as to cover the front surface of the light source 6 (removably so as to cover the light source 1). The light source 6 generates parallel light including a shading of a fixed pattern in the parallel light generated from the light source 6.

The illuminating means 5 is disposed so as to be orthogonal to the axis of the optical disk 1, and irradiates the half mirror 3 with incident light (x) at an incident angle of 45 degrees.

The half mirror 3 reflects the incident light (x) right below, irradiates the incident light (x) on the reflective film of the optical disk 1, and forms a fixed pattern on the reflective film and the protective coat film of the optical disk 1. Reflect the shadow of.

Reference numeral 4 denotes an image pickup device. The center of the optical axis of the image pickup device coincides with the center axis of the optical disk 1. The imaging device 4 captures reflected light (y) including the shadow of the fixed pattern projected on the reflection film and the protective coat film of the optical disk 1 through the half mirror 3.

Reference numeral 8 denotes an image recognizing means for processing the image captured by the image pickup means 4 and confirming whether or not the shading image of the fixed pattern is deformed by the net-like body 7.

Numeral 9 is a discriminating means for discriminating the presence or absence of "coat unevenness" (corrugated unevenness of the protective coat surface) of the protective coat film of the optical disc 1 based on the detection result of the image recognition means.

The operation of this embodiment (●) will be described with reference to FIG. (A) The uniform parallel light emitted from the light source 5 passes through the mesh body 7 to become incident light (x) including a shadow of a fixed pattern. The incident light (x) is incident on the half mirror 3, reflected right below, irradiates the reflection film of the optical disk 1, and projects a fixed pattern shadow on the reflection film and the protective coating film of the optical disk 1. The half mirror 3 reflects the reflected light (y) including the shadow projected on the reflection film and the protective coat film.
Through the imaging device 4. (B) A normal protective coat film (“coat unevenness”)
Without. ) Is taken as a reference image using the reference optical disk 1 having the standard pattern. (C) At the time of inspection, on the optical disk 1 to be inspected, a shadow of a fixed pattern is imaged, and the shadow image is compared with the reference image to recognize the degree of deformation of the fixed pattern. Is determined.

Comparing the effects of the embodiment (●) and the embodiment (●), in the embodiment (●), the imaging means 4 and the illuminating means 5 are arranged at a predetermined angle with respect to the optical disk 1. However, since the image is taken obliquely, the space tends to greatly expand. However, since a half mirror or the like is not used as in the embodiment (●), it can be realized at low cost. In the embodiment (●), since the imaging means 4 and the illuminating means 5 are arranged at right angles and illuminated through the half mirror 3, the mounting of each component does not expand as in the embodiment (●), and It can be made compact.

In both embodiments, the state where no printing is applied to the protective coating film of the optical disk is referred to as the “non-printing state”.
Also, the presence or absence of “coat unevenness” of the protective coat film can be detected satisfactorily. Further, the lighting device of the present embodiment can be realized at a very low cost because it can be realized only by adding a mesh to the front of the light source of the conventional printing surface inspection device. The inspection device can be easily switched to the protective coat film inspection device.

[0030]

The present invention is a simple mechanism in which the front surface of the light source of the illuminating means is simply covered with a mesh, and the presence or absence of "coat unevenness" of the protective coating film is automatically determined, so that it depends on human labor. In addition, a visual inspection was conventionally performed. Inspection of “unevenness” of the protective coat film can be automated.
Further, it is possible to easily switch to the protective coat film inspection apparatus simply by adding a net to the light source of the conventional print surface inspection apparatus for inspecting the print surface of an optical disc.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of a protective coat film inspection apparatus according to an embodiment (●) of the present invention.

FIG. 2 is a cross-sectional view illustrating the structure of an optical disk.

FIG. 3 is a diagram illustrating a reflected light image including a shadow of a fixed pattern captured by an imaging device.

FIG. 4 is a schematic cross-sectional view illustrating a schematic configuration of a protective coat film inspection apparatus according to another embodiment (●) of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 optical disk s, incident light (light ray) t, reflected light x, incident light (light ray) y, reflected light 10 protective coating film inspection device 6 light source 7 mesh body 5 lighting means 4 imaging means 8 image recognition means 9 discriminating means 3 Half mirror

Claims (5)

[Claims] An image of a fixed pattern is projected on a reflection film of an optical disk, and the deformation of the fixed pattern caused by a protective coating film formed on the reflection film is detected. A surface condition of the protective coat film, thereby inspecting the protective coat film of the optical disk. 2. A light beam (s) including a shading of a fixed pattern is radiated at a predetermined incident angle onto a reflection film of an optical disk, and reflected light (t) from the reflection film is imaged. Detecting the deformation of the shading of the fixed pattern caused by the wavy uneven shape of the protective coat film formed on the optical disk, thereby determining the presence or absence of the wavy uneven shape of the protective coat film. Inspection methods. 3. A light beam (x) transmitted through a half mirror and including a shadow of a fixed pattern from directly above, on a reflection film of an optical disk.
And the reflected light (y) from the reflective film is transmitted through the half mirror to capture an image, and the shading of the fixed pattern caused by the wavy irregularities of the protective coat film formed on the reflective film Detecting the presence or absence of a wavy uneven shape of the protective coat film by detecting the presence of a wavy irregular shape. 4. An apparatus for inspecting a protective coat film of an optical disk, comprising: a. Illumination means having a light source whose front surface is covered with a mesh of a fixed pattern, and irradiating a light beam (s) including a shadow of the fixed pattern at a predetermined incident angle toward a reflective film of an optical disk. b. Reflected light (t) including a shadow of the fixed pattern reflected from the reflective film and the protective coat film formed on the reflective film.
Imaging means for imaging the image. c. An image recognition unit that processes the image captured by the imaging unit and recognizes whether or not the shading of the fixed pattern is deformed by the mesh. d. Determining means for determining the presence or absence of a wavy uneven shape on the surface of the protective coating film of the optical disk based on a detection result of the image recognition means. 5. An apparatus for inspecting a protective coat film of an optical disk, comprising: A configuration in which an optical disk, a half mirror, and an imaging unit are arranged in this order coaxially with the axis of the optical disk, and the illumination unit is arranged so as to be orthogonal to the axis of the optical disk; Illumination means having a light source whose front surface is covered with a mesh of a fixed pattern, and irradiating a light beam (x) including a shadow of the fixed pattern at an incident angle of 45 degrees toward the half mirror surface. b. A half mirror having a 45-degree inclination with respect to the axis of the optical disk, and reflecting a light beam (x) emitted from the illuminating means and containing a shadow of the fixed pattern toward the reflection film of the optical disk and directly below the mirror. . c. Imaging means for imaging reflected light (y) including the shadow of the fixed pattern reflected from the reflection film and the protective coat film formed on the reflection film through the half mirror; d. An image recognition unit that processes the image captured by the imaging unit and recognizes whether or not the shading of the fixed pattern is deformed by the mesh. e. Determining means for determining the presence or absence of a wavy uneven shape on the surface of the protective coating film of the optical disk based on a detection result of the image recognition means.