JP2000065748A - Surface inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface inspection apparatus by which an inspection result can be obtained surely when the surface of a mirrorlikely finished member such as, e.g., the signal face of a CD is inspected, whose inspection speed is fast and which is simple and low cost. SOLUTION: In the surface inspection apparatus, the surface of an object to be inspected is irradiated with illumination light from an illumination means 5, and the surface of an adjacent region is inspected on the basis of reflected light from the adjacent region in a part which is hit intensely with the illumination light. In the surface inspection apparatus, a photographing means 3 which photographs the adjacent region is provided, a binarization means which binarizes images photographed by the photographing means 3 is provided, an area counting means which counts the area of the image on one side of the binarized images generated by the binarization means is provided, and a yes-no judgment means which judges yes or no according to the area counted by the area counting means is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection apparatus, and more particularly to a surface inspection apparatus capable of accurately inspecting an article having a mirror-like surface for scratches, holes, and the like.

[0002]

2. Description of the Related Art For example, a CD (compact disk)
In a mass production factory, a case where a CD is completed as a product and a final inspection is performed will be considered. As is well known, the signal surface of a CD is mirror-finished, and when inspecting for scratches, holes, adhesion of protrusions, dirt, and the like, the inspection is generally performed visually by an operator. However, visual inspection is inefficient and unfavorable in terms of increased labor costs. Therefore,
Surface inspection device (for example, JP-A-7-55710,
It is also conceivable to automatically perform a surface inspection using Japanese Patent Application Laid-Open No. 2-50313.

The principle of the above-mentioned surface inspection apparatus is as shown in FIG. 13, in which the surface of the inspection object 101 is irradiated by irradiation means (irradiation part / non-irradiation part generation means) which is not shown, and for example, a slit is formed by using a mask. An irradiated portion 102 and a non-irradiated portion 103 are formed. Then, small scratches, holes, and projections (hereinafter, referred to as scratches) 104 are not visible in the directly irradiated portion 102, but scratches and the like are generated in the non-irradiated portion 103 due to irregular reflection and scattering of the irradiation light of the irradiated portion 102. This makes use of the phenomenon that the user can see the image 104. The term “visible” includes not only visual observation by a human but also photographing means using, for example, a CCD or the like. Further, the “non-irradiated portion” includes a portion having a lower irradiation degree than the irradiated portion.

[0004]

However, when a surface inspection apparatus using the above-mentioned principle is applied to a mirror-finished inspection object such as a CD in a mass production factory or the like, the inspection result can be obtained reliably. It is preferable that the inspection speed is high and that it can be easily and inexpensively constructed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reliable inspection result when inspecting the surface of a mirror-finished member such as a signal surface of a CD. It is to provide a surface inspection device.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention illuminates the surface of an object to be inspected with irradiation light from irradiation means, and reflects light from a region near a portion where the irradiation light is strongly applied. A surface inspection apparatus that performs a surface inspection of the nearby area based on the image capturing means for capturing an image of the nearby area,
Binarizing means for binarizing an image photographed by the photographing means;
An area counting unit that counts an area of one of the binary images generated by the binarizing unit; and a pass / fail determination unit that determines pass / fail based on the area counted by the area counting unit. Features.

Further, when irradiating the surface of the inspection object with irradiation light from the irradiation means, an irradiation part and a non-irradiation part are simultaneously generated by the irradiation part / non-irradiation part generation means, and the irradiation part and the non-irradiation part are generated. A surface inspection apparatus for inspecting a surface of the non-irradiated portion based on reflected light, wherein the irradiated portion / non-irradiated portion generation means generates an irradiation pattern in which the irradiated portion and the non-irradiated portion have an opposite irradiation relationship to each other. Photographing means for photographing an irradiation pattern area generated by each of the two types of masks; binarizing means for binarizing an image photographed by the photographing means; An area counting unit that counts an area of one of the binary images generated by the unit; and a pass / fail determination unit that determines pass / fail based on the area counted by the area counting unit.

With this configuration, the image of the inspection object photographed by the photographing means is binarized, and one area of the binarized image is counted by the area counting means. Since the pass / fail judgment is made, it is possible to provide a surface inspection apparatus which can surely obtain an inspection result, has a high inspection speed, and can be configured at a low cost with a simple configuration.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. The parts already described are given the same reference numerals, and redundant description will be omitted.

(1) First Embodiment FIG. 1 is an overall configuration diagram of a surface inspection apparatus SD1 according to the present embodiment, FIG. 2 is a conceptual diagram in which a flaw or the like is found in the surface inspection apparatus SD1, and FIG. Is a block diagram of a control system of the surface inspection apparatus SD1.

As shown in FIG. 1, a CD (compact disk) 2, which is an "object to be inspected", is placed on an inspection table 1 with its signal surface facing up. Stand 4 above inspection table 1
A video camera 3 which is a “photographing means” fixed to the video camera 3 is installed.
Connect to In addition, an illumination 5 composed of a linear fluorescent lamp, which is an “irradiation unit”, is disposed above the inspection table 1. The illumination 5 moves in the direction of arrow A by moving means (not shown) while forming a linear irradiation surface 6 on the signal surface of the CD 2.

When the signal surface of the CD 2 is irradiated, as shown in FIG. 2, if there is a flaw 8 or the like in a nearby region 7 which is a “neighboring region” of the irradiation surface 6, the irregular reflection and reflection described in the above-mentioned conventional example will be described. By the scattering or the like, it becomes possible to take an image by using the video camera 3 to distinguish between “the scratches 8” and “the portion where no scratches exist”.

Next, a surface inspection apparatus SD1 will be described with reference to FIG.
The configuration of the control system will be described. As shown in FIG. 3, the control system of the surface inspection device SD1 is roughly divided into
, An input device (mouse 22, keyboard 23), an output device (process monitor 21), and a program monitor 21
And a video camera 3 and the like.

The video camera 3 has an image pickup device such as a CCD, and outputs a signal from a not-shown subject (object to be inspected) as a video signal, and an A / D converter constituting an image processing board 11 described below. 12 The image processing apparatus 10 includes an image processing board 11 and a host CPU 1
9 and a program memory 18. The image processing board 11 includes an A / D converter 12 that converts the received video signal into a digital signal and outputs the digital signal, and image memories 13 a and 13 b that store the output of the A / D converter 12.
An image processor 14 which is a "binarizing means" for processing and measuring the image signals stored in the image memories 13a and 13b; an "area counting means" for calculating the stored and processed signals; Image CPU 16,
A D / A converter 15 which receives a digital signal from the image memory 13a, converts the digital signal into an analog signal, and outputs the analog signal;
An image processing monitor 17 for displaying an output from the converter 15 is provided.

The host CPU 19 includes an image CPU 16
To the user, and receive processing data. The program memory 18 stores a user program.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. In the state shown in FIG. 1, the signal surface of the CD 2 is irradiated by the illumination 5 to form an irradiation surface 6. In this case, compared with the irradiation intensity of the irradiation surface 6, the vicinity 7
Irradiation intensity becomes weaker. The video camera 3 photographs the vicinity 7 of the irradiation surface 6 for the first time, and acquires the video signal in the image memory 13a (acquires it on the screen A) (step 1). Unnecessary portions of the acquired image A are masked in the image memory 13a (step 2), and the acquired image A is binarized (step 3).

In the binarized image, a portion caused by a scratch or the like 8 is, for example, binarized to be a white portion (blank portion) in FIG.
Therefore, the area of the white portion is counted (step 4). If the area is equal to or smaller than a predetermined value, the total area of the scratches 8 is small, and it is determined that the first inspection of the irradiated surface is passed (step 4). 5). If the value is equal to or more than the predetermined value, the area of the scratches 8 is large, so that the first inspection is determined to be rejected (step 6).

When the first pass / fail judgment is completed, the inspection at the first position (the state shown in FIG. 1) is completed (step 7). (Step 8), and Step 1
Then, the above-described steps 1 to 7 are repeated until the predetermined inspection area on the signal surface of CD2 (for example, the entire surface of the signal surface of CD) is completed.

(2) Second Embodiment In the surface inspection apparatus SD2 of this embodiment, two types of masks are alternately interposed between the illumination and the CD to generate an irradiated portion and a non-irradiated portion. Is the case.

As shown in FIGS. 5 and 6, the interior of the ring of the illumination 21 composed of a ring-shaped fluorescent lamp fixed to the stand 4 is disposed directly below the lens portion of the video camera 3. In addition, first and second arms 22 and 24 that are rotatable in the directions of arrows B and C are attached to the stand 4,
A mask 23 having a light-transmitting portion (shown in white) 23a and a light-impermeable portion (shown in black) 23b formed concentrically on the distal end of the first arm 22 is fixed. Similarly, a mask 25 having a light transmitting portion (shown in white) 25a and a light non-transmitting portion (shown in black) 25b formed concentrically on the tip of the second arm 24 is fixed.

The diameter of the masks 23 and 25 is slightly larger than the diameter of the CD 2, and the outermost light transmitting portion 23 of the first mask 23 is formed.
a and the outermost light opaque portion 25 of the second mask 25
The dimensions of b are the same. Similarly, the corresponding ring-shaped portions (light transmitting portions and light non-transmitting portions) of the first mask 23 and the second mask 25 have the same dimensions. Then, as shown in FIG. 7, the signal surface of the CD 2 on the inspection table 1 is first covered with the irradiation pattern 27 corresponding to the first mask 23, and the scratches 8 are made visible in the non-irradiated portion, and the video camera 3 Enable shooting. Next, as shown in FIG. 8, the image is covered with an irradiation pattern 28 corresponding to the second mask 25, and the scratches 8 are made visible in the non-irradiated portion so that the video camera 3 can take an image. When the CD2 is covered with the irradiation patterns 27 and 28 using the first and second masks in this manner, it is possible to make the scratches 8 and the like 8 evident by the irradiation pattern over the entire surface of the CD2 without leakage.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

First, the first mask 23 is irradiated with the illumination 21 and the CD2.
Then, the irradiation pattern 27 (FIG. 7) by the first mask 23 is photographed by the video camera 3 and acquired as the screen A in the image memory 13a (step 11). Unnecessary portions of the acquired image A are masked in the image memory 13a (step 12), and the acquired image A is binarized (step 13).

One area of the binarization (for example, a white portion corresponding to a flaw or the like) is counted (step 14). If the area is equal to or smaller than a predetermined value, the flaw or the like 8 passes the first inspection. Then, the arms 22 and 24 are rotated to exchange the first mask 23 with the second mask 25 (step 15). Then, similarly to the above, the irradiation pattern 28 (FIG. 8) by the second mask 25 is photographed by the video camera 3 and acquired as the screen B in the image memory 13b (step 16). Unnecessary portions of the acquired image B are masked in the image memory 13b (step 17), and the acquired image B is binarized (step 18). One area of the binarization result is counted (step 19), and if the area is equal to or smaller than a predetermined value, the flaws 8 etc. are passed in the second inspection, so that it is determined that they pass overall (step 2).
0). In this case, the passed CD 2 is removed from the inspection table 1, and the next CD 2 is placed on the inspection table 1.
From 1 on, the same inspection as described above is performed.

If the area count is equal to or greater than the predetermined value in step 14 and if the area count is equal to or greater than the predetermined value in step 19, the primary inspection or the secondary inspection is rejected (step 21). Finish (Step 2
2).

According to the present embodiment, the mechanical operation in the inspection process is performed only when the arms 22 and 24 are rotated to change the mask, so that the required time for the inspection is shorter than that in the first embodiment. Can be shortened.

(2-1) Modification of Second Embodiment FIGS. 10 and 11 show a modification of the second embodiment. In each case, FIG.
In this case, a mask having a different pattern is used in place of the concentric mask shown in FIG.

FIG. 10 shows a checkered pattern 31a, 3
1b, where the light non-transmissive portion 31c and the light transmissive portion 31d form a pattern in a relationship that complements each other.

FIG. 11 shows vertical stripe patterns 32a and 32b.
This is the case where the light non-transmissive portion 32c and the light transmissive portion 32d form patterns in a relationship that complements each other.

(3) Third Embodiment In this embodiment, a mask 41 shown in FIG. 12 is provided instead of the masks 23 and 25 shown in FIG. This mask 41 divides the concentric circle into four parts and
1a and the light opaque portion 41b are formed, and the center O is disposed immediately below the video camera 3. Then, first, an irradiation pattern is generated on the signal surface of a CD (not shown) in the state of FIG.
The processing up to 4 is performed.

Next, the mask 41 is rotated by 90 ° in the direction of arrow D along the center O, the irradiation pattern of FIG. 12B is generated on the signal surface of the CD, and photographing is performed. The processing from 15 to step 22 is performed. If a mask of the type shown in FIG. 12 is used, the surface inspection apparatus can be made compact.

In the above-described embodiment, the case of a CD has been described as a specific example of the mirror finish. However, a mirror finish other than the CD (for example, various disk-shaped recording media, porcelain, various painted surfaces, etc.) can be used. Of course, the present invention can also be applied.

[0033]

As described above, according to the present invention, an irradiated portion and a non-irradiated portion (including a weak irradiation intensity) are generated on the surface of a mirror-finished inspection object by the irradiating means, and photographed by the photographing means. The image of the inspected object is binarized, and one area of the binarized image is counted by the area counting means, and the pass / fail judgment of the inspected object is performed based on the count result. It is possible to provide a surface inspection apparatus with a simple and inexpensive configuration that can be obtained at a high inspection speed.

[Brief description of the drawings]

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

FIG. 2 is a conceptual diagram when a flaw or the like is found in the first embodiment.

FIG. 3 is a block diagram of a control system according to the first embodiment.

FIG. 4 is an operation flowchart of the first embodiment.

FIG. 5 is an overall configuration diagram of a second embodiment of the present invention.

FIG. 6 is a side view of a main part of the second embodiment.

FIG. 7 is a diagram showing a first irradiation pattern in the second embodiment.

FIG. 8 is a diagram showing a second irradiation pattern in the second embodiment.

FIG. 9 is an operation flowchart of the second embodiment.

FIG. 10 is a diagram showing an irradiation pattern according to a modification of the second embodiment.

FIG. 11 is a diagram showing an irradiation pattern of another modification of the second embodiment.

FIG. 12 is a diagram showing an irradiation pattern according to the third embodiment of the present invention.

FIG. 13 is a view showing an irradiation pattern for explaining the principle of a conventional surface inspection apparatus.

[Explanation of symbols]

SD1, SD2 ... surface inspection device, 1 ... inspection table, 2 ... C
D, 3 video camera, 4 stand, 5, 21 illumination, 6 irradiation surface, 7 inspection area, 8 scratch, etc., 10 image processing device, 23, 25 mask

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G051 AA11 AA37 AA71 AA90 AB01 AB07 AB08 AB12 BB07 BC07 CA04 CB05 CC07 EA11 EA12 EA14 ED01 ED08 FA02 GC04 GC15 GD02 GD06 5D121 HH11 HH18

Claims (5)

[Claims] 1. A surface inspection apparatus that irradiates a surface of an inspection object with irradiation light from an irradiation unit and performs a surface inspection of the vicinity area based on a reflection light from a vicinity area of a portion where the irradiation light is strongly applied. A photographing means for photographing the neighboring area; a binarizing means for binarizing an image photographed by the photographing means; and an area of one of the binary images generated by the binarizing means. A surface inspection apparatus comprising: an area counting means for counting; and a pass / fail judgment means for judging pass / fail according to the area counted by the area counting means. 2. The surface inspection apparatus according to claim 1, wherein the determination unit determines whether the inspection object is acceptable while moving the irradiation unit along the surface of the inspection object. 3. When irradiating the surface of an inspection object with irradiation light from an irradiation unit, an irradiation part and a non-irradiation part are simultaneously generated by an irradiation part / non-irradiation part generation means, and the irradiation part and the non-irradiation part are generated. A surface inspection apparatus that performs a surface inspection of the non-irradiated portion based on reflected light, wherein the irradiated portion / non-irradiated portion generation means generates an irradiation pattern in which the irradiated portion and the non-irradiated portion have an opposite irradiation relationship to each other. Photographing means for photographing an irradiation pattern area generated by each of the two types of masks; a binarizing means for binarizing an image photographed by the photographing means; A table comprising: area counting means for counting the area of one of the binary images generated by the means; and pass / fail determination means for determining pass / fail based on the area counted by the area counting means. Inspection equipment. 4. The two types of masks are formed concentrically on the same plate-like member, and imaging for the pass / fail judgment is performed based on a first irradiation pattern generated by a first mask. The surface inspection apparatus according to claim 3, wherein the imaging for the pass / fail determination is performed based on a second irradiation pattern generated by the second mask by rotating the mask by a predetermined angle. 5. The surface inspection apparatus according to claim 1, wherein the inspection object is a signal surface of a CD.