JPH0772722B2 - Detection sensitivity adjustment device 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 the above, and more particularly to a detection impression adjusting device of an identification type defect detection device capable of identifying and detecting the type, size, position, etc. of detected defects. .

[Conventional technology]

A defect detection device for detecting a defect existing in a transparent plate material, for example, in a transparent glass plate manufacturing line, detects a defect existing in a transparent glass plate to be manufactured, and feeds back the detection result to the transparent glass plate manufacturing process. Therefore, it is necessary to prevent the occurrence of defects at the locations where they occur and to improve the yield of products.

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 the glass plate by detecting only reflected light with respect to irradiation light by a light receiver. To know the disadvantages, 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 detection device disclosed in Japanese Patent Laid-Open No. 51-29988 described 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. 5, 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 cause 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 this case, the far-axis transmitted scattered light 7 that is far from the optical axis of the transmitted light 4 is generated. In addition, the amount of transmitted light 4 decreases for bubbles, foreign matters, bushes, and drip, and the amount of reflected light 8 increases for 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 identification type defect detection device
In the flying spot type defect detection device, a plurality of detecting at least two kinds of light among transmitted light, near paraxial transmitted scattered light, paraxial transmitted scattered light, far axial transmitted scattered light, reflected light, and reflected scattered light, respectively. Each light receiver is provided, the light from each light receiver is converted into an electric signal, and the obtained electric signal is processed to generate defect data including information indicating the type and size of the defect. Further processing is performed to create a defect pattern composed of a bit pattern corresponding to one defect of the glass plate, and the defect pattern thus obtained is collated with a defect identification pattern table prepared in advance to detect the defect. It is configured to determine the type, size, etc. of the.

6 and 7 are a perspective view and a schematic side view of a scanner and a light receiver portion of the already proposed defect detecting device, and the light receiver is exaggeratedly shown.

The scanner is centered on a laser light source 11 that emits laser light and an axis 13 parallel to the direction in which the laser light 12 from the laser light source 11 enters and the transparent glass plate 10 travels (hereinafter referred to as the Y-axis direction). The rotary polygon mirror 14 that rotates at a high speed and the axis 15 that is parallel to the Y-axis direction in which the transparent glass plate 10 travels, that is, the direction parallel to the width direction of the glass plate (hereinafter referred to as the X-axis direction). Parallel mirror 16 for plate thickness correction that can change the angle
It has and. The position of the laser light source 11 shown in FIG. 7 is different from the actual position,
This is to avoid obscuring the drawings. The scanner having the above-described configuration is installed above the traveling transparent glass plate 10.

One photodetector D1 for detecting the transmitted light 17 is provided on the side opposite to the side where the scanner is provided, that is, below the transparent glass plate 10.
And two photodetectors D2 _A and D2 for detecting near paraxial transmitted scattered light.
_B and two photodetectors D3 _A and D3 for detecting paraxial transmitted scattered light
_B and two photodetectors D4 _A and D4 _B for detecting far-axis transmitted scattered light 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 elongated in the X-axis direction. The structure of the light receiver D1 will be described below as a representative.

FIG. 8 is a perspective view of the light receiver D1. This photodetector D1 is formed by arranging a large number of optical fibers 21, and one end of the optical fibers 21 is arranged in two rows as shown in the figure and fixed by being embedded in resin or the like, and the photodetector main body 22 Make up. 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 arranging the photodetectors D1, D2 _A , D2 _B , D3 _A , D3 _B , D4 _A , D4 _B for detecting transmitted light and transmitted scattered light having the above structure,
In FIG. 7, each light receiver is arranged so that the light receiving surface is positioned within each effective light receiving angle with reference to the optical axis of the transmitted light 17. Second example of relationship between each light receiver and effective light receiving angle
Shown in the table.

The photodetectors D1, D2 _A , D2 _B , D3 _A , D3 _B , D4 _A , and D4 _B arranged so that the light receiving surface is located within the effective light receiving angle as seen from the light receiving surface side. It is shown in FIG. 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. 6 and 7, the other end of the optical fiber of the photodetector D1 is connected to the photomultiplier tube PM1, and the other ends of the optical fibers of the photodetectors D2 _A and D2 _B are bundled to form a photomultiplier tube PM2. 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 other ends of the optical fibers of the photodetectors D4 _A and D4 _B are bundled and photomultiplied. It is connected to the 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.

Although not shown, a light receiver for forming a start pulse is provided between the rotary polygon mirror 14 and the parallel mirror 16 of the scanner, and the light received by this light receiver and sent by the optical fiber is transmitted. A photoelectric converter for converting into an electric signal and a pulse shaper are provided, and a start pulse ST indicating the start of scanning is formed.

Now, in the proposed identification type defect detection device including the scanner 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 high speed, and the rotating polygon The laser beam 12 is shaken in the X-axis direction by the mirror 14, reflected by the parallel mirror 16, and then projected onto the traveling transparent glass plate 10 to scan the glass plate in the X-axis direction. The laser beam 12 repeatedly scans the transparent glass plate 10 every time the reflecting surface of the rotary polygon mirror 14 changes. 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. 7, the laser light 12 is projected onto the transparent glass plate 10 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.

If there is a defect in the transparent glass plate, if the laser light hits this defect, the type of defect (foreign matter, bubble, stick, drip)
As a result, the amounts of transmitted light and reflected light are changed, and at the same time transmitted and scattered light is generated.

For example, when the type of defect is a bush, when the incident laser light hits the bush, the amount of transmitted light changes, and at the same time, near paraxial transmitted scattered light is generated. The change in the amount of transmitted light is
It is detected by the photodetector D1, sent to the photomultiplier tube PM1, and converted into an electric signal. On the other hand, the near paraxial transmission scattered light is incident on the light receiving surfaces of the photo detectors 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. The transmitted and scattered light is received by the photodetectors D3 _A and D3 _B , and the received light is the photomultiplier tube P
It is sent to M3 and converted into an electrical 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. This far-axis transmitted scattered light is received by the photodetectors D4 _A and D4 _B , and the received light is the photomultiplier tube P
It is sent to M4 and converted into an electrical 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]

The proposed identification type defect detection device is a ribbon-shaped glass plate,
Or, it is left in a line where a cut glass plate or the like flows to detect a defect, but when the light transmittance and the light reflectance are different due to the difference in the thickness and color of the glass plate flowing through the line. In order to maintain the detection accuracy of defects, the detection sensitivity must be kept constant.

An object of the present invention is to change the thickness, color, etc. of an inspection object according to
An object of the present invention is to provide a detection sensitivity adjusting device that adjusts the detection sensitivity of the identification type defect detecting device.

[Structure of Invention]

The present invention scans a traveling transparent plate material with a light spot in a direction perpendicular to the traveling direction, receives at least transmitted light and transmitted scattered light with a plurality of light receivers, and converts the received light into an electric signal with a photoelectric converter. A detection sensitivity adjusting device used for an identification type defect detection device that detects defects existing in the transparent plate material by converting it, and a sample storage shelf for storing the transparent plate material sample, and a reference light from the scanning light. , A reference light capturing means for transmitting the transparent plate material sample taken out from the sample storage shelf and then making it enter each of the light receivers, a means for sampling the taken-in reference light, and a sampling value based on the sampling value. And a control means for controlling the gain of the photoelectric converter connected to the light receiver.

〔Example〕

 Next, examples of the present invention will be described.

1 to 4 are views showing an embodiment of the present invention.
FIG. 1 shows the photodetector parts of the photodetectors D1, D2 _A , D2 _B , D3 _A , D3 _B , D4 _A , D4 _B that receive the transmitted light and the transmitted scattered light of the identification type defect detection device, FIG. 1 is a view of the light receiver portion viewed from the Y-axis direction, and FIG. 2 is a view of the light receiver portion viewed from the X-axis direction. Note that, in FIG. 1, the light receiver is represented by a symbol D as a representative. In the figure, 14 is a rotary polygon mirror, 12 is a laser beam, and the laser light source and the parallel mirror are not shown.

In the present embodiment, the detection sensitivity adjusting device for the photomultiplier tube PM2 for the near paraxial transmitted scattered light will be described as a representative, but the photomultiplier tube PM1 for the transmitted light and the photoelectron for the paraxial transmitted scattered light are described. The multiplier tube PM3, the photomultiplier tube PM4 for far-axis transmitted scattered light, and the photomultiplier tube PM5 for reflected light can be realized with the same configuration.

As shown in FIGS. 1 and 2, the detection sensitivity adjusting apparatus of the present embodiment is provided with a light receiver 31 in the scanning light above the traveling glass plate 30 and an optical fiber 32. One end of the glass plate is connected to this receiver, and the other end of the glass plate is located at a position off the line through which the glass plate 30 flows.
Lead to 34. An optical fiber 33 is provided at the other end of the optical fiber 32 so that one end faces the other end with a certain distance, and the other end of this optical fiber is a photomultiplier tube for near paraxial transmission scattered light.
Connect to PM2. The light taken into the photomultiplier tube PM2 via the light receiver 31 and the optical fibers 32 and 33 will be referred to as reference light hereinafter.

The glass plate sample insertion part 34 has a photoelectric limit switch.
35 is provided, this photoelectric limit switch is composed of a light emitting portion and a light receiving portion, when the glass plate sample 37 is inserted into the space where the optical fibers 32 and 33 face each other, it is reflected by the glass plate sample. By receiving the light from the light emitting portion at the light receiving portion, it is detected that the glass plate sample is inserted into the insertion portion 34.

In the vicinity of the glass plate sample insertion portion 34, a sample shelf 38 for storing a plurality of glass plate samples is provided, and the insertion and removal of the glass plate sample from the sample shelf and the insertion and removal of the glass plate sample are performed mechanically. This is performed by the sample moving mechanism unit 36 which is any means.

FIG. 3 is a diagram showing an electric circuit portion of the detection sensitivity adjusting apparatus of this embodiment. This electric circuit portion counts the clock CLK and is reset by the output of the photoelectric limit switch 35, and the sampling pulse output from this counter, and the reference in the electric signal output of the photomultiplier tube PM2. Reference light signal RS which is the part corresponding to light
Sampling circuit 42 for sampling, hold circuit 43 for holding the sampling value, and hold circuit 43
And a control circuit 44 for controlling a high-voltage generation circuit 45 that supplies a voltage applied to the photomultiplier tube PM2 based on the sampling value from.

Next, the operation of this embodiment will be described with reference to the signal waveform diagram of FIG.

In FIG. 1, it is assumed that the laser beam scans the glass cutting plate 30 in the X-axis direction from left to right. The light that has entered the light receiver 31 during one scan, that is, the reference light, is sent to the photomultiplier tube PM2 via the optical fiber 32 and the optical fiber 33.
Therefore, the electric signal output from the photomultiplier tube PM2 is
As shown in FIG. 4A, the reference light signal RS corresponding to the reference light is output for each scanning.

When detecting a defect of a certain type of glass plate 30, first, the sample moving mechanism unit 36 is driven in advance, and the glass plate sample shelf 38 is used to select the glass plate sample 37 of the same type as the glass plate 30 to be inspected. It is taken out, inserted into the glass plate sample insertion portion 34, and held for a predetermined time. The photoelectric limit switch 35 detects the insertion of the glass plate sample 37,
A detection signal as shown in FIG. 4 (b) is output. During the ON period T of this detection signal, the glass plate sample 37 is inserted into the insertion portion 34.
Corresponds to the period held in. During this period T,
The reference light is input to the photomultiplier tube PM2 via the photoreceiver 31, the optical fiber 32, the glass plate sample 37, and the optical fiber 33, and the photomultiplier tube PM2 outputs the reference light signal RS. The level of the reference light signal RS during this period depends on the transmittance that changes depending on the color, thickness, etc. of the glass plate sample 37.

On the other hand, the detection signal of the photoelectric limit switch 35 is
It is input to 41 and resets the counter at its rising edge. The clock CKL in FIG. 4C, which is synchronized with the reference light signal RS, is input to the counter 41, and the counter 41 outputs a sampling pulse SP to the sampling circuit 42 after counting a predetermined number of this clock. Counter 41
The above-mentioned counter number is the detection period T of the glass plate sample 37.
The sampling pulse SP is output at about half the time. This sampling pulse SP is the fourth
It is shown in FIG.

In the sampling circuit 42, this sampling pulse SP
The reference light signal R from the photomultiplier tube PM2
Sample S. The sampled value is held by the hold circuit 43 and input to the control circuit 44. The control circuit 44 compares the input sampling value with the reference level and sets the applied voltage generated by the high voltage generation circuit 45 based on the comparison result. The applied voltage thus set determines the sensitivity of the photomultiplier tube PM2. This sensitivity is maintained while the same type of glass plate 30 flows through the line.

When the defect detection of the same type of glass plate is completed as described above and the defect detection of another type of glass plate having a different color etc. is performed, the photoelectron is performed before the defect detection operation in the same manner as described above. Adjust the sensitivity of the multiplier again.

As described above, according to this embodiment, it is possible to adjust the detection sensitivity of the identification type defect detection device in accordance with the color, thickness, etc. of the glass plate. Further, it is clear that the detection sensitivity adjusting apparatus of this embodiment can make the detection sensitivity of the identification type defect detecting apparatus constant even with respect to changes in the laser light output and deterioration of the sensitivity of the photomultiplier tube.

Although one embodiment of the present invention has been described above, the detection means provided in the glass plate sample insertion portion is not limited to the photoelectric limit switch, and may be a mechanical limit switch.

Further, in the above examples, the taking out of the sample from the glass plate sample shelf and the taking in and out of the sample insertion portion are carried out by mechanical means, but without providing such mechanical means, an operator It may be done manually each time.

Further, in the above embodiments, the photomultiplier tube is used as a means for converting the light from the light receiver into an electric signal, but generally any photoelectric converter capable of gain control may be used. Of course.

〔The invention's effect〕

As described above, according to the present invention, it is possible to set the detection sensitivity adapted to the glass plate to be inspected in the identification type defect detection device, so that it is possible to increase the detection sensitivity of the identification type defect detection device. Become.

[Brief description of drawings]

1 and 2 are views showing an embodiment of the present invention, FIG. 3 is a view showing an electric circuit portion of the embodiment, and FIG. 4 is a view for explaining an operation of the embodiment. Waveform diagram, FIG. 5 is a diagram showing transmitted light and transmitted scattered light, FIG. 6 is a perspective view of an already proposed identification type defect detection device, and FIG. 7 is a schematic view of an already proposed identification type defect detection device. FIG. 8 is a side view, FIG. 8 is a perspective view of the light receiver, and FIG. 9 is a plan view of the light receiving surfaces of a plurality of light receivers for transmitted light and transmitted scattered light. 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 transmitted scattered light Optical receiver 30 …… Glass plate 31 …… Receiver 32,33 …… Optical fiber 34 …… Glass plate Sample insertion part 35 …… Optical limit switch 36 …… Sample moving mechanism part 37 …… Glass plate sample 38… Glass plate sample rack 41 Counter 42 Sampling circuit 43 Hold circuit 44 Control circuit 45 High voltage generation circuit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuo Miyano 480 Shimohara, Kamifujisawa, Iruma City, Saitama Prefecture Yasukawa Electric Co., Ltd. Tokyo factory (56) References Japanese Patent Publication No. 57-37023 (JP, B2)

Claims (1)

[Claims] 1. A traveling light-transmitting plate material is scanned with a light spot in a direction perpendicular to the traveling direction, at least transmitted light and transmitted scattered light are received by a plurality of light receivers, and the received light is converted into an electric signal by a photoelectric converter. Is a detection sensitivity adjusting device used for an identification type defect detection device for detecting defects existing in the transparent plate material, and a sample storage shelf for storing the transparent plate material sample, and a reference light from the scanning light. A reference light capturing means for capturing and transmitting the transparent plate material sample taken out from the sample storage shelf and then making it enter each of the light receivers, a means for sampling the captured reference light, and a sampling value based on a sampling value. And a control means for controlling the gain of a photoelectric converter connected to the photodetector, the detection sensitivity adjusting device of the identification type defect detecting device.