JPH07110302A - Defect detector for transparent board - Google Patents

Abstract

PURPOSE:To detect defects in a test specimen by providing a mask having a transparent part and an opaque part between the test specimen and an illumi nation light source before the test specimen is irradiated with illumination light from one side to pick up its transmitted light by the light source by means of a camera from the other side. CONSTITUTION:A test specimen 1 is transported in a predetermined direction by a transporter. Light is emitted to the test specimen 1 from an illumination light source 4 in synchronism with the image pickup signal of a TV camera 2. Defects of the specimen 1 are detected from the image pickup signal of the camera 2 by means of a defect detection circuit 3. A mask 11 having a transparent part 11a and an opaque part 11b is provided between the specimen 1 and the light source 4. This causes the specimen 1 to have a bright part 9 by the transparent part 11a of the mask 11 and a dark part 10 by its opaque part 11b. Since a bubble 8 in the specimen 1 is irradiated with no light from the dark part 10, this comes in shade to allow the outline of the bubble 8 to be detected as a contrast image. The opaque part 11b of the mask 11 is provided in a stripe or mesh form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent plate defect detecting device suitable for use in a detecting device for detecting various defects in a plate-shaped transparent object such as glass or plastic.

[0002]

2. Description of the Related Art Conventionally, a plate-like transparent object to be inspected is illuminated with illumination light, the reflected light or transmitted light is imaged by a television camera, and the signal is detected by an electronic circuit to detect defects in the object to be inspected. There is proposed a defect detection device that does.

FIG. 4 and FIG. 5 are side views of a conventional transparent plate defect detection device used for defect inspection of a plate-shaped transparent object. 4 and 5, reference numeral 1 denotes a plate-shaped transparent object to be inspected, which is conveyed in a predetermined direction by a conveying device (not shown). Reference numeral 2 denotes a television camera, which is a general black and white television camera. Defect detection circuit 3 is composed of a differentiating circuit and the like.
It is a circuit for detecting the defect of.

Reference numeral 4 denotes an illumination light source, which is composed of, for example, strobe light, and emits light in synchronization with an image pickup signal of the television camera 2 with respect to an object to be inspected 1 conveyed by a conveying device (not shown). Reference numeral 5 is a light diffusion plate, which is made of frosted glass or the like and diffuses the strobe light of the illumination light source 4.

FIG. 4 is a reflection type transparent plate defect detecting device, and FIG. 5 is a transmission type transparent plate defect detecting device.
The defect detection apparatus for a transparent plate shown in FIG. 4 differs from the defect detection apparatus for a transparent plate shown in FIG. This is the point provided on the side opposite to the side provided.

The above-described reflection type transparent plate defect detecting apparatus shown in FIG. 4 irradiates the object 1 to be inspected with light from the illumination light source 4, and the television camera 2 reflects the light reflected from the surface of the object 1 to be inspected.
To detect a defect, and mainly to inspect for a defect on the surface of the object 1 to be inspected, for example, the presence or absence of unevenness on the surface.

The above-described transmission type defect detection apparatus shown in FIG. 5 detects a defect by catching the transmitted light of the object 1 to be inspected by the illumination light source 4 with the television camera 2, and mainly in the object 1 to be inspected. It is used for detecting black foreign matter. In any of the defect detection devices shown in FIGS. 4 and 5, a light diffusion plate 5 is provided between the illumination light source 4 and the inspection object 1 and the inspection object 1 is irradiated with diffused light. Is configured.

[0008]

However, the above-mentioned FIG.
In the conventional reflection-type defect detection device shown in FIG. 1, the reflected light on the surface of the object to be inspected 1 is captured by the television camera 2 to detect the defect. It was Further, as shown in FIG. 6, in the conventional transmission type defect detection apparatus shown in FIG.
As defects in the object 1 to be inspected, convex portions 6 and concave portions 7 on the surface
If the bubbles 8 inside are present, these defects are diffusely reflected by the illumination light source 4 by the periphery of the defect portion in the inspected object 1 as shown by the arrow in FIG. It is illuminated brightly by light, and contrast of light and dark cannot be obtained, and it cannot be distinguished as a defective portion.
Therefore, there is an inconvenience that bubbles cannot be detected and only black foreign matter can be detected.

The present invention has been made in view of the above points, and an object thereof is to provide an inexpensive transparent plate detecting apparatus capable of easily detecting a defect in an object to be inspected.

[0010]

A transparent plate defect detecting apparatus according to the present invention is a transparent plate defect detecting apparatus for detecting a defect of an object 1 to be inspected, as shown in FIGS. , An illumination light source 4 which applies illumination light from one side of the inspected object 1, a television camera 2 which images the transmitted light of the inspected object 1 by the illumination light source 4 from the other side, and the inspected object 1
And a mask 11 having a transparent portion 11a and an opaque portion 11b between the illumination light source 4 and the light source 4.

The transparent plate defect detection apparatus of the present invention is
For example, as shown in FIGS. 1 to 3, the opaque portion 11b of the mask 11 is provided in a stripe shape.

Further, the transparent plate defect detecting apparatus of the present invention is
For example, as shown in FIGS. 1 to 3, the opaque portion 11b of the mask 11 is provided in a mesh shape.

[0013]

According to the present invention, the mask 11 having the transparent portion 11a and the opaque portion 11b between the object 1 to be inspected and the illumination light source 4 is provided.
Since the transparent portion 1 of the mask 11 is provided inside the inspected object 1,
A bright portion 9 due to 1a and a dark portion 10 due to the opaque portion 11b of the mask 11 are generated, and since the bubble 8 in the inspected object 1 is not irradiated with light from the dark portion 10, it becomes a shadow, and the contour of the bubble 8 is contrasted. It can be detected as a certain image.

Further, according to the present invention, since the opaque portion 11b of the mask 11 is provided in a stripe shape, the transparent portion 11a of the mask 11 causes the bright portion 9 and the opaque portion 11b of the mask 11 in the inspected object 1. Since the dark portion 10 and the dark portion 10 are formed in a stripe shape and the light is not emitted from the dark portion 10 to the bubble 8 in the inspected object 1, this becomes a shadow, and the outline of the bubble 8 can be detected as an image with contrast.

Further, according to the present invention, since the opaque portion 11b of the mask 11 is provided in a mesh shape, the light portion 9 by the transparent portion 11a and the dark portion 10 by the opaque portion 11b are mesh-shaped in the object 1 to be inspected. Since the light is not emitted from the dark portion 10 to the bubble 8 in the inspected object 1, it becomes a shadow, and the contour of the bubble 8 can be detected as an image with contrast.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the detection device according to the present invention will be described in detail below with reference to FIGS. 4 to 6
Portions corresponding to the conventional transparent plate defect detection device shown in 1 are denoted by the same reference numerals and detailed description thereof will be omitted.

FIG. 1 shows one construction of an embodiment of the transparent plate defect detecting apparatus of the present invention. Reference numeral 1 denotes a plate-shaped transparent object to be inspected, which is conveyed in a predetermined direction by a conveying device (not shown). Reference numeral 2 denotes a television camera, which is a general black and white television camera. Reference numeral 3 denotes a defect detection circuit, which is composed of a differentiating circuit or the like and is a circuit for detecting a defect of the inspected object 1 from an image pickup signal of the television camera 2.

Reference numeral 4 denotes an illumination light source, which is composed of, for example, strobe light, and emits light in synchronization with an image pickup signal of the television camera 2 with respect to an object to be inspected 1 conveyed by a conveying device (not shown). Reference numeral 5 is a light diffusion plate, which is made of frosted glass or the like and diffuses the strobe light of the illumination light source 4.

The embodiment of the defect detecting device for a transparent plate of the present invention shown in FIG. 1 is different from the conventional defect detecting device for a transparent plate shown in FIGS. Board 5
The point is that a stripe-shaped or mesh-shaped mask 11 having a transparent portion 11a and an opaque portion 11b is provided between and. 2A shows a stripe-shaped mask, and FIG. 2B shows a mesh-shaped mask.

As described above, when the stripe-shaped mask as shown in FIG. 2A is used, the strobe light of the illumination light source 4 diffused by the light diffusing plate 5 is applied to the mask 11, so that the mask 11 is exposed. The transparent portion 11 of the mask 11 is provided on the inspection object 1.
Illumination of a striped pattern is performed by a and the opaque portion 11b.

As a result, as shown in FIG. 3, the transparent portion 11a of the mask 11 and the bright portion 9 of the mask 11 and the dark portion 10 of the opaque portion 11b of the mask 11 are alternately formed in stripes in the object 1 to be inspected. Since light does not strike the bubble 8 in the object 1 from the dark portion 10, it becomes a shadow, and the contour of the bubble 8 can be detected as an image with contrast.

Further, the object 1 to be inspected is conveyed from the front end to the end thereof in a direction orthogonal to the stripe formed by the transparent portion 11a and the opaque portion 11b of the mask 11 by a conveying device (not shown). Here, by matching the conveyance pitch with the pitch of the stripes of the transparent portion 11a and the opaque portion 11b, it is possible to inspect all of the object 1 to be inspected from the front end to the end. In other words, the transparent portion 11a of the mask 11 is conveyed so that the bright portion 9 is entirely generated in the inspected object 1.

Further, as described above, when the mesh-shaped mask as shown in FIG. 2B is used, the strobe light of the illumination light source 4 diffused by the light diffusion plate 5 is applied to the mask 11. The inspected object 1 is illuminated with a mesh-shaped pattern by the transparent portion 11a and the opaque portion 11b of the mask 11.

As a result, as shown in FIG. 3, a bright portion 9 by the transparent portion 11a of the mask 11 and a dark portion 10 by the opaque portion 11b of the mask 11 are formed in a mesh shape in the object 1 to be inspected. Since the light is not emitted from the dark portion 10 to the bubbles 8 therein, this becomes a shadow, and the outline of the bubbles 8 can be detected as an image with contrast.

Further, the object 1 to be inspected is conveyed in a predetermined direction from its leading end to its trailing end by a conveying device (not shown). Here, by matching the conveyance pitch with the mesh pitch of the transparent portion 11a and the opaque portion 11b, it is possible to inspect all of the object 1 to be inspected from the front end to the end. In other words, the transparent portion 11a of the mask 11 is conveyed so that the bright portion 9 is entirely generated in the inspected object 1.

In this case, since the mesh-shaped mask 11 is surrounded by the dark portion 10 in a spot shape around the defect portion as compared with the stripe-shaped mask 11, the contour of the defect portion further has a bright and dark contrast, and the defect portion is further enhanced. Can be easily detected.

In the above example, the mesh-shaped mask 11
Shows an example in which the stripe-shaped mask 11 is formed so as to be orthogonal and the shape of the mesh is a quadrangle, but the shape of the mesh may be a hexagon, an octagon, another polygon, or a circle.

The mask 11 is preferably provided at a distance sufficiently away from the object 1 to be inspected. When the object 1 to be inspected is approached and the focus of the TV camera 2 is entered, the mask 1
This is because the black and white boundary line of the stripe-shaped or mesh-shaped pattern 1 is erroneously detected as a defective portion by the defect detection circuit 3.

Therefore, the mask 1 seen from the TV camera 2
1 is best taken as an out-of-focus, blurred image. That is, in order to prevent the black and white boundary line from being detected when the mask 11 is provided in the focus-matching portion of the television camera 2 close to the inspected object 1, as shown in FIG.
, As shown in
The mask 11 may be formed by gradually blurring between the transparent portion 11a and the opaque portion 11b.

Although the size of the opaque portion 11b of the mask 11 may correspond to the size of the defect to be detected, the thickness of the black line of the opaque portion 11b of the mask 11 is usually 1 mm. It has been found that ~ 2 millimeters is suitable.

In the above example, the object 1 to be inspected is conveyed by the not-shown conveying device.
Needless to say, the mask 11 may be fixed and the object 1 to be inspected may be conveyed by a conveying device (not shown), and the two may be relatively displaced to perform the inspection.

As described above, by inserting the mesh-shaped or stripe-shaped mask 11 between the object 1 to be inspected and the illumination light source 4, the defect in the object 1 to be inspected on the transparent plate can be easily detected, and the cost can be reduced. The device can be configured.

Needless to say, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0034]

According to the present invention, since the mask having the transparent portion and the opaque portion is provided between the object to be inspected and the illumination light source,
A bright part due to the transparent part of the mask and a dark part due to the opaque part of the mask are generated in the object to be inspected, and the air bubbles in the object to be inspected are not exposed to light from the dark part. It can be detected as a certain image.

Further, according to the present invention, since the opaque portions of the mask are provided in stripes, the light portions due to the transparent portions of the mask and the dark portions due to the opaque portions of the mask are alternately arranged in stripes in the object to be inspected. Since the light is not emitted from the dark part to the air bubbles in the object to be inspected, this becomes a shadow,
The contour of the bubble can be detected as a contrasting image.

Further, according to the present invention, since the opaque portion of the mask is provided in a mesh shape, a bright portion due to a transparent portion and a dark portion due to an opaque portion are generated in a mesh shape in the object to be inspected, and the object to be inspected is formed. Since the light does not reach the air bubbles in the body from the dark part, it becomes a shadow, and the outline of the air bubbles can be detected as an image with contrast.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of an embodiment of a transparent plate defect detection apparatus of the present invention.

2A and 2B are views showing a mask of an embodiment of a transparent plate defect detection apparatus of the present invention, FIG. 2A is a stripe mask, FIG. 2B is a mesh mask, and FIG. 2C is a stripe pattern with blurred black and white boundaries. It is a mask.

FIG. 3 is a diagram for explaining the operation of an embodiment of the transparent plate defect detection apparatus of the present invention.

FIG. 4 is a side view showing a configuration of an example of a conventional transparent plate defect detection apparatus.

FIG. 5 is a side view showing the configuration of another example of a conventional transparent plate defect detection apparatus.

FIG. 6 is a diagram illustrating the operation of a conventional transparent plate defect detection apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspected object 2 TV camera 3 Defect detection circuit 4 Illumination light source 5 Light diffusing plate 6 Convex part 7 Concave part 8 Bubble 9 Bright part 10 Dark part 11 Mask 11a Transparent part 11b Opaque part

Claims (3)

[Claims] 1. A defect detecting device for a transparent plate for detecting a defect of an inspected object of a transparent plate, comprising: an illumination light source for applying illumination light from one side of the inspected object; A defect detecting device for a transparent plate, comprising: a television camera that images transmitted light from the other side; and a mask having a transparent portion and an opaque portion between the object to be inspected and the illumination light source. 2. The defect detecting device for a transparent plate according to claim 1, wherein the opaque portion of the mask is provided in a stripe shape. 3. The defect detecting device for a transparent plate according to claim 1, wherein the opaque portion of the mask is provided in a mesh shape.