JPH087161B2 - Plate thickness compensator for identification type defect detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a transparent plate material, such as a glass plate or a plastic plate, by scanning a light spot on a plate material (hereinafter referred to as a transparent plate material) that transmits at least light. The present invention relates to a flying-spot type defect detection device for detecting defects existing in a sheet, and more particularly to a plate thickness correction device for an identification type defect detection device capable of identifying and detecting the type, size, position, etc. of the detected defect. .

[Conventional technology]

The defect detection device for detecting defects existing in the translucent plate material,
For example, in a transparent glass plate production line, the defects existing in the transparent glass plate to be manufactured are detected, and the detection result is fed back to the transparent glass plate manufacturing process to prevent the occurrence of defects at the occurrence position, It is required to improve the yield.

In a conventional transparent glass plate defect detection device, for example, as is known in Japanese Patent Laid-Open No. 51-29988, the presence of a glass plate by detecting only reflected light with respect to irradiation light by a light receiver. To know the drawbacks, or JP-A-51-1184
As known from Japanese Patent Laid-Open Publication No. JP-A-2003-242, there is one that detects a defect existing in a glass plate by detecting only transmitted light with respect to irradiation light with a light receiver.

The defect detecting device disclosed in Japanese Patent Laid-Open No. 51-29988 mentioned above can detect defects on the glass surface, but cannot detect defects inside the glass.

On the contrary, the defect detection device disclosed in Japanese Patent Laid-Open No. 51-1184 can detect defects inside the glass, but defects on the glass surface cannot be detected or are very difficult to detect. There is a problem.

Further, the defect detection device as described above cannot identify the type of defect (foreign matter, foam, stick, drip, etc.),
Further, since one light receiver detects bubbles and foreign matter at the same level, there is a defect that foreign matter is overlooked and bubbles and the like are overlooked.

As a defect detecting apparatus for improving such a defect, the present applicant has proposed an identification type defect detecting apparatus capable of identifying the type of defect. The outline of the already proposed discrimination type defect detection device will be described below.

For example, the disadvantages of existing glass plates include bubbles formed by bubbles remaining inside the glass plate, foreign substances formed when foreign substances remain inside the glass plate, and almost all melted foreign substances leaving a tail inside the glass plate. There are a brush formed by remaining in a pulled shape, a drip formed by the tin of the bath adhering to the surface of the glass plate, and the like.

When such a defect exists in the glass plate, when a light spot is projected on the defect, the states of transmission, transmission scattering, reflection, and reflection scattering differ depending on the type of the defect. As shown in FIG. 10, when the light beam 3 is projected onto the defect 2 existing on the transparent glass plate 1 at a constant incident angle α with respect to the normal line, the fluff, the foreign matter, and the bubbles generate transmitted scattered light. In particular, in the case of a bush, the near paraxial transmitted scattered light 5 that is closest to the optical axis of the transmitted light 4 is generated, and in the case of a foreign substance, the paraxial transmitted scattered light 6 that is close to the optical axis of the transmitted light 4 is generated. In the case, the far-axis transmitted scattered light 7 separated from the optical axis of the transmitted light 4 is generated. In addition, bubbles, foreign matter, sticks
The light amount of the transmitted light 4 decreases with both drip, and the light amount of the reflected light 8 increases with drip.

Therefore, a light receiver for individually detecting transmitted light, near-paraxial transmitted scattered light, paraxial transmitted scattered light, far-axis transmitted scattered light, and reflected light is provided to change the amount of transmitted light and reflected light and The types of defects can be identified by detecting the presence or absence of transmitted scattered light, paraxial transmitted scattered light, and far axis transmitted scattered light.

Table 1 shows a summary of the above relationships. The circles in the table indicate with which light the defect type can be identified.

Based on the above facts, the proposed discrimination type defect detection device is a flying spot type defect detection device, and in the flying spot type defect detection device, transmitted light, near paraxial transmitted scattered light, paraxial transmitted scattered light, far axis transmitted scattered light, reflected light, A plurality of light receivers for detecting at least two kinds of reflected / scattered light respectively are provided, the light from each light receiver is converted into an electric signal, and the obtained electric signal is processed to determine the kind and size of the defect. Defect data including information indicating the level is generated, these defect data are further processed to create a defect pattern consisting of a bit pattern corresponding to one defect of the glass plate, and the defect pattern thus obtained is The type, size, etc. of the defect are determined by collating with a defect identification pattern table created in advance.

FIG. 11 and FIG. 12 are a perspective view and a schematic side view of a projector and a light receiver portion of the already proposed defect detecting device, and the light receiver is exaggeratedly shown.

The floodlight is centered on a laser light source 11 that emits a laser light and an axis 13 parallel to the traveling direction of the transparent glass plate 10 (hereinafter referred to as the Y-axis direction) upon receipt of the laser light 12 from the laser light source 11. A rotary polygon mirror 14 that rotates at high speed is provided. In addition,
The position of the laser light source 11 shown in FIG. 12 is shown differently from the actual position, in order to avoid obscuring the drawing. The floodlight having the above configuration is installed above the traveling transparent glass plate 10.

One light receiver for detecting the transmitted light 17 on the side opposite to the side where the light projector is provided, that is, below the transparent glass plate 10.
D1 and two photodetectors D that detect near paraxial transmitted scattered light
2 _A , D2 _B, and two photo detectors D for detecting paraxial transmitted scattered light
3 _A , D3 _B, and two receivers D for detecting far-axis transmitted scattered light
4 _A and D4 _B are arranged. On the other hand, above the transparent glass plate 10, one light receiver D5 for detecting the reflected light 18 is arranged.

The plurality of light receivers basically have the same structure and have a linear light receiving surface in the width direction of the transparent glass plate 10 (hereinafter, referred to as X axis direction). The structure of the light receiver D1 will be described below as a representative.

FIG. 13 is a perspective view of the light receiver D1. This receiver D1
A large number of optical fibers 21 are arranged, and one end of the optical fibers 21 is arranged in two rows as shown in the figure and embedded and fixed in a resin or the like to form a light receiver main body 22. The end faces 23 of 21 of a large number of arranged optical fibers are gathered to form an elongated linear light receiving face 24. The other ends of the optical fibers are bundled and connected to a photomultiplier tube described later.

When the photodetectors D1, D2 _A , D2 _B , D3 _A , D3 _B , D4 _A , and D4 _B for detecting transmitted light and transmitted scattered light having the above structure are arranged, the transmitted light 17 shown in FIG. The respective light receivers are arranged such that the light receiving surface is located within each effective light receiving angle with respect to the axis. Table 2 shows an example of the relationship between each light receiver and the effective light receiving angle.

Light receivers D1, D2 _A , D2 _B , D3 _A , D3 _B , D4 _A , D4 arranged so that the light receiving surface is located within the effective light receiving angle as described above.
FIG. 14 shows _B as seen from the light-receiving surface side. The length direction of the light receiving surface of each light receiver is parallel to the X-axis direction. The use of two light receivers for detecting the near-paraxial transmitted scattered light, the paraxial transmitted scattered light, and the far-axis transmitted scattered light in this way is to prevent the generated transmitted scattered light from being overlooked.

In FIGS. 11 and 12, the other end of the optical fiber of the photodetector D1 is connected to the photomultiplier tube PM1 and the photodetectors D2 _A and D2 _B are connected.
The other ends of the optical fibers are bundled and connected to the photomultiplier tube PM2, and the other ends of the optical fibers of the photodetectors D3 _A and D3 _B are bundled and connected to the photomultiplier tube PM3, and the photoreceiver D4 _A , The other ends of the optical fibers of D4 _B are bundled and connected to the photomultiplier tube PM4, and the other end of the photodetector D5 is connected to the photomultiplier tube PM5. Each photomultiplier tube converts the light received by each light receiver into an electric signal.

Now, in the proposed identification type defect detection device provided with the light projector and the light receiver having the above-mentioned configuration, the laser light 12 emitted from the laser light source 11 is incident on the rotating polygon mirror 14 rotating at a high speed, and the rotating polygon mirror. The laser beam 12 is shaken in the X-axis direction by 14 and then projected onto the traveling transparent glass plate 10 to scan the glass plate in the X-axis direction. Each time the reflecting surface changes due to the rotation of the rotary polygon mirror 14, the laser light 12 is transmitted through a transparent glass plate.
Repeat 10 scans. Since the transparent glass plate 10 runs in the Y-axis direction, the entire surface of the glass plate is scanned by the laser light.

As shown in FIG. 12, the laser light 12 is
The transparent glass plate 10 is projected at an incident angle α in the Y-axis direction with respect to a normal line perpendicular to the glass plate surface. This is to prevent the light reflected on the back surface of the transparent glass plate 10 and subsequently reflected on the front surface from interfering with the transmitted light. The value of the incident angle α is preferably 13 ° or more.

When there is a defect in the transparent glass plate, when the laser beam hits this defect, the amount of transmitted light and reflected light changes depending on the type of defect (foreign matter, bubble, stick, drip), and at the same time transmitted scattered light occurs. To do.

For example, if the defect type is a bush, and the incident laser light hits the bush, the amount of transmitted light changes and
Proximity paraxial transmission scattered light is generated. The change in the amount of transmitted light is detected by the photodetector D1 and sent to the photomultiplier tube PM1.
It is converted into an electric signal. On the other hand, the near paraxial transmitted scattered light is
The light is incident on the light-receiving surfaces of the photodetectors D2 _A and D2 _B. The received near paraxial transmission scattered light is sent to the photomultiplier tube PM2 and converted into an electric signal.

Similarly, for example, when the defect type is foreign matter, when the incident laser beam hits the foreign matter, the amount of transmitted light changes and paraxial transmitted scattered light is generated at the same time. This transmitted scattered light is
The light received by the photodetectors D3 _A and D3 _B is sent to the photomultiplier tube PM3 and converted into an electric signal.

Similarly, for example, when the type of defect is bubbles, when the incident laser light hits the bubbles, the amount of transmitted light changes and, at the same time, far-axis transmitted scattered light is generated. The far-axis transmitted scattered light is received by the photo detectors D4 _A and D4 _B , and the received light is sent to the photomultiplier tube PM4 and converted into an electric signal.

Similarly, for example, when the type of defect is a drip, when the incident laser beam hits the drip, the amount of transmitted light changes and the amount of reflected light changes at the same time. This change in reflected light is detected by the photodetector D5, sent to the photomultiplier tube PM5, and converted into an electric signal.

The electrical signal from the photomultiplier tube is sent to the processing unit, defect data including information indicating the type and size of the defect is generated, and these defect data are further processed to correspond to one defect of the glass plate. A defect pattern including a bit pattern is created, and the defect pattern thus obtained is collated with a defect identification pattern table created in advance to determine the type and size of the defect.

Since the configuration of the processing unit is not directly related to the present invention, the description is omitted.

[Problems to be solved by the invention]

In the already proposed discrimination type defect detection device, as described above, in order to avoid the interference of the laser light, the laser light from the projector is obliquely incident on the glass plate. Therefore, as shown in FIG. 15, when the plate thickness of the glass plate 10 changes from h ₁ to h ₂ , the transmitted light 17 has its optical axis deviated as shown by 17 ′ and the reflected light 18 has 18 ′. As a result, as a result of the deviation of the optical axis, in each light receiver, the light receiving sensitivity of not only the transmitted light and the reflected light but also the transmitted scattered light is deteriorated, and the detection sensitivity of the identification type defect detecting device is lowered.

The present invention solves such a problem, and when the plate thickness of the translucent plate material to be inspected is changed, the plate thickness correcting device corrects the light according to the plate thickness so that the light is effectively incident on the light receiver. To provide.

[Structure of Invention]

The present invention scans a translucent plate material traveling in the length direction in the width direction with a beam-shaped scanning light from a light projector, and transmits among the transmitted light, the transmitted scattered light, the reflected light, and the reflected scattered light from the translucent plate material. It is used for an identification type defect detection device for detecting at least two kinds of light by a plurality of light receivers to detect defects existing in the transparent plate material, and when the plate thickness of the transparent plate material changes, A plate thickness correction device that corrects the position of light incident on a light receiver according to changes in plate thickness, including position detection means for detecting the position of light incident on the light receiver, and position of light incident on the light receiver. It is characterized by further comprising drive means for driving an object to be driven which is driven to correct the above, and control means for controlling the drive means according to the position information from the position detection means.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a plate thickness correcting device of a first embodiment for a photodetector for transmitted light and a photodetector for transmitted scattered light using a rotatable parallel mirror. Note that, in FIG. 1, the illustration of the transmitted scattered light receiver is omitted.

According to this embodiment, a line scan type CCD camera 25 is provided at the end of the light receiving surface of the transmitted light receiver D1, and an axis parallel to the X axis direction is provided between the rotary polygon mirror 14 and the glass plate 10. Two parallel mirrors 27 and 28 that rotate around 26
The parallel mirror 29 is provided on the parallel mirror support mechanism 32. The parallel mirror 29 is, for example, a drive unit 30 such as a motor.
Is driven to rotate. The drive unit 30 is controlled by the control unit 31 to which the position detection signal from the CCD camera 25 is input.

FIG. 2 (a) is a diagram showing the light receiving surface of the CCD camera 25, which is a one-dimensional line CCD of 1024 bits or 2048 bits.
The sensor 33 is arranged in the Y-axis direction. Therefore, when the light spot 34 reaches the one-dimensional line CCD sensor 33, the CCD
The camera 25 outputs a position detection signal indicating the position of incident light in the Y-axis direction. FIG. 2B shows a video signal as a position detection signal from the CCD camera 25. From this video signal, the current position of the incident light in the Y-axis direction can be known. From the viewpoint of detection sensitivity, if the position of the incident light in the Y-axis direction that should be originally incident on the light receiving surface of the light receiver D1 is the origin position 35, and the thickness of the glass plate 10 changes, the current position of the incident light is the origin. It will move from position 35.

FIG. 3 is a diagram for explaining the function of the parallel mirror 29. The two mirrors 27 and 28 are arranged so as to face each other in parallel, and the two mirrors about the axis 26 are arranged relative to each other. It is supported by a support mechanism 32 so that it can rotate while maintaining its position. Now, the two mirrors 27 and 28 are in position 2 shown in FIG.
7a and 28a, the laser light 12 from the rotary polygon mirror 14 is first reflected by the mirror 27 and then reflected by the mirror 28 and projected onto the glass plate 10 along the optical axis 12a. When the parallel mirror 29 is rotated leftward from the above state and the two mirrors are brought to the positions 27b and 28b shown in the figure, the laser light 12 incident on the parallel mirror 29 is guided along the optical axis 12b. Is emitted. By rotating the parallel mirror 29 in this way, the optical path of the laser beam 12 projected on the glass plate 10 can be shifted. Therefore, when the plate thickness of the glass plate 10 to be inspected changes, the incident position of the transmitted light 17 on the light receiver D1 can be corrected by rotating the parallel mirror 29.

 Next, the operation of this embodiment will be described.

A glass plate to be inspected in the plate thickness correcting device of FIG.
When the plate thickness of 10 changes, the optical path of the transmitted light 17 deviates as described above. When the transmitted light 17 whose optical path is deviated enters the CCD camera 25, the current position of the transmitted light 17 is detected and input to the control unit 31. The control unit calculates the magnitude of the deviation of the transmitted light from the original position and the direction of the deviation, controls the drive unit 30 by the control signal, and rotates the parallel mirror 29 to move the transmitted light 17 Adjust so that is at the origin position of receiver D1.

The operation of the control unit 31 will be described in more detail with reference to the flowchart of FIG. The control unit is a CCD camera 2
The current position is read based on the position detection signal from 5 (step). Next, (current position-origin position) is calculated, and the deviation is calculated (step). The absolute value of the calculated deviation is taken and whether the deviation is positive or negative is detected (step). If the deviation is positive, the transmitted light in FIG.
17 is shifted to the right of the origin position 35, and if the deviation is negative, the transmitted light 17 is shifted to the left of the origin position 35.

Next, the absolute value of the deviation is compared with a maximum value (MAX) preset in the control unit 31 (step), and when the absolute value of the deviation is larger than the maximum value, the control unit 31 has a CCD camera abnormality, for example. Is displayed abnormally and the plate thickness is not corrected (step). When the absolute value of the deviation is smaller than the maximum value, the minimum value (MIN) preset in the control unit 31 is further compared with the absolute value of the deviation (step).
If the absolute value of the deviation is smaller than the minimum value, it is determined that the deviation is not enough to correct, and the control signal is not output, and the process returns to step. When the absolute value of the deviation is larger than the minimum value, the control signal is output to the drive unit 30. This control signal contains the absolute value of the deviation, that is, the magnitude of the deviation of the current position of the transmitted light 17 with respect to the origin position, and the direction of the deviation that indicates whether the deviation of the deviation of the transmitted light with respect to the origin position. Is included. The drive unit 30 rotates the parallel mirror 29 based on the control signal from the control unit 31, and corrects the transmitted light 17 so that the transmitted light 17 reaches the origin position 35.

As described above, according to the present embodiment, the parallel mirror is provided between the projector and the glass plate, and the parallel mirror is rotated to change the optical path of the laser light projected on the glass plate. Even if the plate thickness changes, the optical path of transmitted light can be kept constant. Moreover, if the optical path of the transmitted light does not change, the optical path of the transmitted scattered light does not change. Therefore, the light receiving sensitivities of the light receiver for transmitted light and the light receiver for transmitted scattered light are not deteriorated, so that the detection sensitivity of the identification type defect detection device can be kept good as a whole.

The first embodiment described above is an example using the parallel mirror, but it is understood that the projector itself may be moved without using the parallel mirror. FIG. 5 shows a second embodiment based on this idea. Laser light source 11 and rotating polygon mirror
The projector having 14 is supported by a projector support mechanism 43 that can move as a unit in parallel to the Y-axis direction. This embodiment is similar to the first embodiment in that the CCD camera 40 provided at the end of the light receiver D1 and the control unit 41 that outputs a control signal based on the transmitted light detection position signal from this CCD camera. And a drive unit 42 that drives the support mechanism 43 based on a control signal from the control unit. The operation of these elements is similar to that of the first embodiment, and when the thickness of the glass plate 10 is changed from h ₁ to h ₂ as shown in the figure, the incident light 12 passes through the optical path indicated by the dotted line 12 '. The entire projector may be moved in the Y-axis direction so that it is projected on the plate 10.

Although the projector itself is moved in the second embodiment described above,
On the contrary, it is understood that the light receiver itself may be moved. Sixth
In the figure, a third embodiment based on this idea is shown. It should be noted that the light receiver for the transmitted scattered light is not shown in order to avoid obscuring the drawing.

The light receiver for transmitted light and the light receiver for transmitted scattered light are supported by a light receiver support mechanism 53 that can move as a unit in parallel to the Y-axis direction. In this embodiment, similar to the first and second embodiments, a CCD camera 50 provided at the end of the photodetector D1 and
The control unit 51 outputs a control signal based on the transmitted light detection position signal from the CCD camera, and the drive unit 52 drives the support mechanism 53 based on the control signal from the control unit. The operation of these elements is the same as in the first and second embodiments, and the thickness of the glass plate 10 is h ₁ as shown in the drawing.
From changes to h _2, when the optical path of the transmitted light 17 is changed as shown by the dotted line 17 ', the entire light receiver in the Y-axis direction by the driving unit 52 so that this transmission light comes to the home position of the photodetector D1 Just move.

In the above third embodiment, the light receiver itself is moved,
The light receiver may be fixed, a rotatable optical path changing mirror may be provided between the light receiver and the glass plate, and the optical path may be changed by rotating the mirror. FIG. 7 shows a fourth embodiment based on this idea. The illustration of the light receiver for the transmitted scattered light is omitted. A mirror 65, which is rotatable about an axis 64 parallel to the X-axis direction, is provided in the optical path of the transmitted light and the scattered light from the glass plate 10 for changing the optical path by reflecting the light and the light receiver. Different from each of the above-mentioned embodiments, is arranged in the optical path of the light reflected by the mirror 65. The optical path changing mirror 65 is rotatably supported by the support mechanism 63.

This embodiment is similar to the first to third embodiments in that the photodetector D1
CCD camera 60 provided at the end of the, a control unit 61 that outputs a control signal based on a transmitted light detection position signal from the CCD camera, and an optical path changing mirror based on the control signal from the control unit. It is composed of a drive unit 62 for rotating 65. The operation of these elements is the same as in the first to third embodiments, the thickness of the glass plate 10 is changed from h ₁ to h ₂ as shown, and the optical path of the transmitted light 17 is changed as shown by the dotted line 17 '. In the case of change, the drive unit 62 may rotate the optical path changing mirror 65 so that the transmitted light comes to the origin position of the light receiver D1.

Each of the above examples was the plate thickness correction device for the transmitted light receiver and the transmitted scattered light receiver, but when the identification type defect detection device also includes the reflected light receiver D5, In addition, it is necessary to correct the plate thickness of the reflected light receiver. FIG. 8 is a diagram showing a fifth embodiment in this case. According to this embodiment, the light receiver D5 that receives the reflected light 18
Is supported by a support mechanism 73 that can move in parallel to the Y-axis direction, and a CCD camera 70 provided at the end of the light receiver D5,
The control unit 71 outputs a control signal based on the reflected light detection position signal from the CCD camera, and the drive unit 72 drives the support mechanism 73 based on the control signal from the control unit. The operation of these elements is the same as in each of the above embodiments, and when the plate thickness of the glass plate 10 is changed from h ₁ to h ₂ as shown and the optical path of the reflected light 18 is changed as shown by the dotted line 18 ′. First, the drive unit 72 may move the light receiver D5 in the Y-axis direction so that the reflected light comes to the origin position of the light receiver D5.

In this embodiment, the photodetector D5 is of the optical fiber type whose light-receiving surface is extremely elongated, but the photodetectors for transmitted light and transmitted scattered light must be arranged very close to each other due to the effective light-receiving angle. Therefore, as compared with the case where an optical fiber type light receiver has to be used, a scattering box (collection box) having a wide light receiving surface can be used as a light receiver for reflected light. A sixth embodiment using such a scattering box is shown in FIG.

In this embodiment, a CCD camera 80 is provided at the end of a scattering box type reflected light receiver D5, and a mask having a slit 81 extending in the X-axis direction is provided on the front surface of the light receiving surface of the light receiver D5.
82 is provided. This mask is X parallel to the front of the receiver D5.
It is supported so as to move in a direction perpendicular to the axial direction.
In addition, FIG. 9 (a) is a view of the photodetector D5 viewed from the X-axis direction,
FIG. 9B is a view of the photodetector D5 viewed from the mask side.

This embodiment is similar to each of the above-described embodiments in that
A control unit 84 that outputs a control signal based on the reflected light detection position signal from the D camera 80 and a drive unit 83 that drives the mask 82 based on the control signal from this control unit are provided.

According to the present embodiment, the CCD camera 80 has a receiver D for the reflected light 18.
The incident position on 5 is detected and the current position detection signal is sent to the control unit 84.
Send to The control unit 84 controls the driving unit 83 to drive the mask 82 so that the reflected light 18 is taken into the light receiver D5 from the slit 81 of the mask 82. Therefore, even if the plate thickness of the glass plate 10 changes and the optical path of the reflected light 18 shifts, the mask can be driven accordingly and the reflected light can be taken into the light receiver.

In the above embodiment, only the reflected light is taken in through the slit of the mask, but it is also possible to take in only the reflected scattered light.

Although the embodiments of the present invention have been described above, the means for detecting the incident position of the transmitted light or the reflected light on the light receiver is CC
Of course, the position is not limited to the D camera, and other position detecting means may be used.

〔The invention's effect〕

As described above, according to the present invention, in the identification type defect detection device for detecting a defect of the transparent plate material, the plate thickness of the transparent plate material to be inspected is changed, and transmitted light, transmitted scattered light, reflected light, Even if the optical path of the reflected / scattered light is changed, it can be corrected so that the light receiver can effectively receive the light. Therefore, the defect can be detected with high sensitivity.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a diagram for explaining the functions of the CCD camera of the first embodiment, and FIG. 3 is a diagram showing the first embodiment. FIG. 4 is a view for explaining the function of the parallel mirror, FIG. 4 is a flow chart for explaining the operation of the control unit of FIG. 1, FIG. 5 is a view showing a second embodiment of the present invention, and FIG. FIG. 7 is a diagram showing a third embodiment of the present invention, FIG. 7 is a diagram showing a fourth embodiment of the present invention, FIG. 8 is a diagram showing a fifth embodiment of the present invention, FIG. 9 is a diagram showing a sixth embodiment of the present invention, FIG. 10 is a diagram showing transmitted light and transmitted scattered light, and FIG. 11 is a perspective view of an already proposed identification type defect detection device. FIG. 13 is a schematic side view of an already proposed identification type defect detection device, FIG. 13 is a perspective view of a light receiver, and FIG. 14 is a plan view of a light receiving surface of a plurality of light receivers for transmitted light and transmitted scattered light, Figure 15 shows Is a diagram showing a deviation of the optical path of the transmitted light and reflected light when the plate thickness of the plate is changed. D1 …… Receiver for transmitted light D2 _A , D2 _B …… Receiver for near paraxial transmitted scattered light D3 _A ， D3 _B …… Receiver for paraxial transmitted scattered light D4 _A ， D4 _B …… Far axis scattered scattering Optical receiver 10 …… Glass plate 11 …… Laser light source 12 …… Laser light 14 …… Rotating polygon mirror 17 …… Transmitted light 18 …… Reflected light 25,40,50,60,70,80 …… CCD camera 29 …… Parallel mirror 30,42,52,62,72,83 …… Drive unit 31,41,51,61,71,84 …… Control unit 33 …… One-dimensional line CCD sensor 65 …… Optical path changing mirror 81 …… Slit 82 …… Mask

Front Page Continuation (72) Inventor Junichi Abe 480 Shimohara, Upper Fujisawa, Iruma City, Saitama Prefecture, Tokyo Factory, Yasukawa Electric Co., Ltd. Yasukawa Electric Co., Ltd. Tokyo factory

Claims (6)

[Claims] 1. A beam-shaped scanning light from a light projector scans a light-transmissive plate material traveling in the length direction in the width direction to obtain transmitted light, transmitted scattered light, reflected light, and reflected scattered light from the light transmissive plate material. Used in an identification type defect detection device for detecting at least two kinds of light with a plurality of light receivers to detect defects existing in the transparent plate material, and when the plate thickness of the transparent plate material changes, A plate thickness correction device that corrects the position of light incident on the light receiver in accordance with the change in the plate thickness, including position detection means for detecting the position of light incident on the light receiver, and light incident on the light receiver. Discrimination type defect detection, comprising: a driving unit that drives a driven object that is driven to correct a position; and a control unit that controls the driving unit according to position information from the position detecting unit. Device thickness correction device. 2. The plate thickness correction device for an identification type defect detection device according to claim 1, wherein the driven object is a rotation provided between the light projector and the translucent plate member. A plate thickness correction device for an identification type defect detection device, which is a possible parallel mirror. 3. The plate thickness correction device for an identification type defect detection device according to claim 1, wherein the driven object is a light receiver. Correction device. 4. The plate thickness correction device for an identification type defect detection device according to claim 1, wherein the driven object is a light projector. apparatus. 5. A plate thickness correction device for an identification type defect detection device according to claim 1, wherein the driven object is rotatable between a light transmitting plate and a light receiver. Thickness correction device for an identification type defect detection device, characterized in that it is a simple optical path changing mirror. 6. The plate thickness correction device for an identification type defect detection device according to claim 1, wherein the driven object is a mask provided on the front surface of the light receiver. Thickness correction device for mold defect detection device.