JPH02116739A - Detector for light transmitting object - Google Patents

Abstract

PURPOSE:To detect a flaw accurately in a short time by computing a difference between an image an obtained when light is transmitted through a light transmitting object provided on a light transmitting planar body and a normal image stored to identify whether the flaw is present depending on the resulting value. CONSTITUTION:A glass plate 1 to be inspected is placed on an X-Y table 2 and when a table 2 is scanned in a direction X being irradiated with light from a power source 3, a pulse is obtained with a width thereof corresponding to the width of a flaw, if any, when present in a transparent electrode of the glass plate 1. When a computing circuit 8 computes a difference between an output of an image pickup means 4 and a normal image pickup image stored in a memory 7, a waveform alone corresponding to the flaw is obtained. The waveform is discriminated by the specified discrimination level; when the level exceeds a specified value, the flaw is judged to be present. This enables automatic detection of a flaw present in a light transmitting object accurately in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid crystal display, for example, in which a transparent electrode, which is a light-transmitting object, has a scratch on the surface of a glass plate, which is a light-transmitting plate. Translucent elements such as beads made of synthetic resin or other materials are used to detect the The present invention relates to a device for detecting objects.

2. Description of the Related Art In a typical prior art, in order to inspect a glass plate on which a transparent electrode is formed, which constitutes a liquid crystal display device, for scratches on the transparent electrode, the glass plate is placed above a light source, and the glass plate is placed above a light source. An operator visually inspects the transparent electrode on the opposite side from the light source.

Problems to be Solved by the Invention In such prior art, since visual inspection is performed, it is obvious that individual differences occur, and scratches on the electrodes may be overlooked, or even inadvertent scratches may occur. Even though the product should be judged as good, it may be judged as defective, resulting in an excessively high defective rate.

Furthermore, in this prior art, the width of the transparent electrode is, for example, 100 μm, and the external shape of the glass substrate on which such a transparent electrode is formed over the entire surface is, for example, 30 cm in length.
Inspecting the transparent electrodes of such a relatively large glass plate, which is 30 cm wide, requires a relatively long time of about 10 to 15 minutes per glass plate.

Moreover, in Manako's prior art, the fj work of inspection is monotonous and requires a high degree of skill.

An object of the present invention is to enable automatic detection of the presence or absence of scratches on a transparent object provided on a transparent plate-like body or the existence of a transparent object in a short period of time. An object of the present invention is to provide a detection device for a transparent object.

Means for Solving the Problems The present invention provides a light source that transmits light through a transparent plate-like body and a transparent object provided thereon, and a light source that transmits light through a transparent plate-like body and a transparent object provided thereon. , a means for taking an image on the side opposite to the light source, a means for storing an image taken by the imaging means of a light-transmitting plate-like body on which a normal light-transmitting object is provided, and a means for storing an image of a light-transmitting plate-like body on which a normal light-transmitting object is provided; calculation means for determining the difference between the output of the imaging means that images the provided translucent plate-like body and the content of the storage means; and means for responding to the output of the calculation means and determining the level of the difference. A detection device for a light-transmitting object is characterized in that it includes:

Further, the present invention provides a light source that irradiates a light-transmitting plate-like body and a light-transmitting object provided thereon, and a light-transmitting plate-like body and a light-transmitting object that are placed on the same side as the light source. means for storing an image taken by the imaging means of a translucent plate-like body on which a normal translucent object is provided; and a translucent plate on which a normal translucent object is provided. The apparatus is characterized by comprising: a calculation means for determining the difference between the output of the imaging means that images the sexual plate and the content of the storage means; and means for determining the level of the difference in response to the output of the calculation means. This is a detection device for translucent objects.

The present invention is characterized in that the transparent plate-like body is supported via a polarizing plate on the opposite side of the plate-like body from the light source.

Further, the present invention provides a light source that irradiates a light-transmitting plate-like body and a light-transmitting object provided thereon, and a light-transmitting plate-like body and a light-transmitting object that are placed on the same side as the light source. means for level-discriminating the output of the imaging means; a polarizing plate disposed on the opposite side of the plate-like body from the light source; 1 is a translucent object detection device, characterized in that the device has a satin finish, and includes means for supporting a polarizing plate.

Function According to the present invention, the light-transmitting plate-like body is provided with a light-transmitting object, and the light-transmitting plate-like body is, for example, a glass plate, and the light-transmitting object is The intervening piece may be a synthetic resin bead or the like that forms a space for sealing the transparent electrode or liquid crystal. Light from a light source is transmitted through or irradiated onto a plate-like object and a transparent object, and an image is captured by a line image sensor or the like on the opposite side of the light source or on the same side as the light source. The storage means first stores an image of a light-transmitting plate-like body provided with a normal light-transmitting object. Next, an image of the light-transmitting plate-like body on which the light-transmitting object to be inspected is provided is taken, and the difference from the contents of the storage means is determined. This difference is level-discriminated. Therefore, even if there is unevenness in the illuminance distribution due to the light source, this will not cause any damage to the transparent object or erroneous detection of the transparent object itself.

In a configuration in which the light source and the imaging means are arranged on the same side with respect to the plate-like body, a polarizing plate is provided on the opposite side of the plate-like body from the light source and the imaging means, so that the reflected light from the light source is directed to the imaging means. to prevent false detection from occurring.

Furthermore, according to the present invention, even if a support that causes diffused reflection is provided on the side opposite to the plate-like body of the polarizing plate, for example, a support means having a matte surface, it is possible to reliably prevent false detection due to reflected light. can.

Embodiment FIG. 1 is an overall system diagram of an embodiment of the present invention. A glass plate 1, which is a transparent plate-like body of a liquid crystal display device, can be displaced by an X-Y table 2 in an X-axis and a Y-axis that are perpendicular to each other in a horizontal plane. The light source 3 is moved together with the glass plate 1 by the X-Y table 2, is provided below the glass plate 1, generates light below the glass plate 1, and transmits the light. An imaging means 4 is provided at a fixed position above the glass plate 1. The imaging means 4 is a line image sensor comprising an objective lens and a number of charge-coupled devices (abbreviated as CCD) on which an image of the glass plate 1 is formed by the lens, and the charge-coupled devices are arranged in the Y direction. configured.

The output of the imaging means 4 is given to an analog-to-digital conversion circuit 5 and an image processing diagram i? Image processing is performed at 86, and the contents are stored in the memory 7.

The contents of the memory 7 are calculated in the calculation circuit 8, and the XY table 2 is controlled by the controller 9 based on the result. The calculation results are displayed by the cathode ray tube 10 and printed by the printer 11.

FIG. 2 is a plan view of the glass plate 1. This glass plate 1
A transparent electrode 12, which is a light-transmitting object, is formed on one surface of the electrode. A transparent electrode 12 on a glass plate 1 and the transparent electrode 1
There is a difference in density between the region 13 where no 2 is formed and the region 13 when light is transmitted.

The transparent electrode 12 may have scratches 14, 15, etc., and the width d1 of the scratch 14 in the X direction is the amount of transparency vf112.
When the total width dO is equal to the total width dO, it can be determined that the electrode 12 is cut. The width do of the electrode 12 is, for example, 100 μm, the vertical length of the glass plate 1 in the Y direction is, for example, 30 cm, and the horizontal length in the X direction is, for example, 30 cm.

Referring to FIG. 3(1), the electrode 12 formed on this glass plate 1 is shown again. this? A scratch 16 exists on the S pole 12. In this situation, the wound 16
While scanning the vicinity in the X direction with the X-Y table 2,
When the imaging means 4 takes an image with a shift in the Y direction, the arithmetic circuit 8 can obtain a signal 17 corresponding to the flaw 16 as shown in FIG. 3(2). Based on this signal 17, the width in the X direction is obtained as indicated by reference numeral 18, and its width d1 can be calculated. This width d1 is the amount of transparency! Ii! When the width do is equal to 12, the voltage vf
! It can be determined that 12 are separated.

It is also possible to determine the width d2 of the flaw 16 in the Y direction on the basis of the signal 17, as indicated by a single reference numeral.

Without installing the glass plate 1 on the X-Y table 2,
When the light source 3 is moved in the X direction by the X-Y table 2, the unevenness of the illuminance distribution in the X direction of the light source 3 is as shown in FIG.
An illuminance distribution is obtained in which the illuminance is high at the center of the direction and low at both ends. The illuminance distribution of the light source 3 is uniform in the X direction, and the glass plate 1 is mounted on the X-Y table 2.
When the transparent electrode 12 is in a normal state with no scratches, the waveform 12a corresponding to the electrode 12 and its electric current [1]
A waveform 13a corresponding to the region 13 of the glass plate where the waveform 2 is not provided is obtained. Therefore, the light source 3 is
) A signal waveform obtained by the imaging means 4 when the glass plate 1 on which a normal, i.e., scratch-free transparent electrode 12 is formed is scanned in the X direction by the X-Y table 2. is now shown in Figure 4 (3), and the waveform shown in Figure 4 (3) is as shown in Figure 4 (1).
) and the waveform of FIG. 4 (2) are superimposed. A normal transparent electrode 1 as shown in FIG. 4 (3)
The imaging means 4 first stores the imaging result of the glass plate 1 having a 2-in-1 image in the memory 7.The imaging means 4 detects pixels at a large number of gradations corresponding to the intensity of the received light, and the gradation for each pixel is Stored in memory 7.

The waveform obtained when the glass plate 1 to be inspected next is mounted on the X-Y table 2 and scanned in the X direction is, for example, the waveform shown in FIG. 4 (4). Scratch 1 on electrode 12
6, a pulse having a width corresponding to the width d3 of the scratch 16 in the X direction is obtained, as shown in the pulse waveform 20 of FIG. 4(4). Based on the output of the imaging means 4 and the output of the memory 7, the arithmetic circuit 8 calculates the output from the imaging means 4 as shown in FIG.
The light intensity level having the waveform shown in FIG. 4 (3), which is stored in advance in the memory 7, is subtracted and calculated for each corresponding pixel from the light intensity level having the waveform shown in 4). The difference is determined as shown in FIG. 4 (5).

As a result, only waveform 20 corresponding to @16 is obtained,
This waveform 20 can be accurately determined without being adversely affected by unevenness in the illuminance distribution of the light source 3. This waveform 20
is level-discriminated at a predetermined discrimination level 11, and when the waveform 20 is equal to or higher than the discrimination level 11, it can be determined that a flaw exists.

FIG. 5 is a flowchart for explaining the operation of the arithmetic circuit 8. Moving from step s1 to step s2,
A glass plate 1 to be inspected is placed on an X-Y table 2. Prior to placing the glass plate 1 to be inspected, the glass plate 1 is X-
The displacement of the Y table 2 is adjusted. When the glass plate 1 to be inspected is aligned with the position of the above-mentioned normal glass plate, in step S4, the glass plate 1 to be inspected is moved and scanned in the X direction by the X-Y table 2. , such scanning in the X direction is shifted in the X direction and the scanning is repeated. The output of the imaging means 4 during scanning in the X direction is converted into a digital value by an analog-to-digital conversion circuit 5.

In step s5, the stored contents of a glass plate having a scratch-free transparent electrode stored in advance in the memory 7;
The difference in light intensity level from the imaged result of the glass plate 1 to be inspected is determined, thus obtaining the waveform shown in FIG. 4 (5). In step S6, the level of the waveform shown in FIG. 4 (5) is discriminated. When the waveform 20 corresponding to the flaw 16 is equal to or higher than the predetermined discrimination level 4, it is assumed that the flaw 16 exists, and the process moves from step S7 to step S8, where a flag is turned on. For example, when the glass plate 1 is scanned in the X direction by the X-Y table 2 in FIG.
), a flag 20a corresponding to the flaw can be obtained, and flags 20a and 20b corresponding to the flaw can be obtained, as shown in FIG. 6(2).

In step s9, the connection of the scratch 16 in the X direction and in the
The coordinate position according to table 2 is stored in memory 7. For example, when the flag 20c is obtained as a result of scanning in the X direction as shown in FIG. 6(3), this flag 20c
The coordinate position is stored in the memory 7 as corresponding to the starting edge of the scratch.

In step s9, for example, as shown in FIG. 6(3), the flag 20d is set to
If it is determined that the flaw is adjacent to c, and therefore the flaw is continuous, the process moves to step s12, and it is detected whether there is a connection with another flaw, that is, an overlap. If there is no overlap with other scratches, step s14
Then, the coordinate positions of the flaw flags are further stored in the memory 7. For example, in step S9, as shown in FIG. It can be determined that they are connected, and flag 20j is set.

20k, it can be determined that the scratches on the pond are connected, and in step s12, these flags 20
Scratches from f to 20h and flag 20j.

It can be determined that the wound at 20 is not connected.

As shown in Figure 6 (5), flag 201° 20m
, 20n, one flaw is connected, and another flaw is connected as shown by flags 20p, 20q, and 2On, and these two flaws are connected and overlap at flag 2On. It is determined that there is. When the scratches overlap like this, flag 2
The flaws from 01 to 20n are connected to the flaws from flags 20p, 20q, and 2On.
The calculation can be performed in step s13 assuming that there are scratches from 1 to flag 20p. In step s15, the width of the scratch is calculated and, for example, as shown in FIG.
), find the width d4 of the scratch in the X direction.

In step s16, it is determined whether the calculated width of the scratch is equal to the total width do of the transparent electrode 12, or whether the total width do is equal to or greater than a predetermined value of the groove width. If the size is large and the product is defective, it is assumed that a defective product is detected in step s17, and the subsequent inspection of the glass plate 1 is stopped.

In the aforementioned step s9, the connection of scratches is checked, and as a result, when it is determined that the scratch is at the end, in step s18, the already counted number of scratches is incremented by 1, and the next number is counted. In step s19, the stored contents of the coordinate position of the flaw including the terminal end are cleared.

When one scanning operation in the X direction is completed, the process moves to step S20, moves by a predetermined distance in the Y direction, and performs X scanning again.In step s21, it is determined whether scanning of the entire surface of the glass plate 1 has been completed. If the inspection has been completed, the inspection is terminated in step s22.

If there is no scratch in step S7, it is determined in step s23 whether the flag is on. When the flag is on,
It is determined that the pixel whose flag is on is the end of the scratch. In step s24, the total number of scratches is determined by adding the stored number to the count value already stored in the memory 7. In step s25, the flag is turned off and all stored coordinate positions of scratches are cleared.

When the flag is off in step s23,
It is determined that there is no scratch, and the process moves to step s20.

FIG. 7 is a simplified perspective view of another embodiment of the invention. In this embodiment, a light source 23 irradiates the glass plate 1 with light. The imaging means 4 is arranged on the same side as the light source 23 with respect to the glass plate 1 (above in FIG. 7), and images the glass plate 1 and the transparent electrode formed thereon.

Glass plate 1 is placed on polarizing plate 24 . Regarding this polarizing plate 24, the side opposite to the glass plate 1 (lower side in FIG. 7)
The rigid support plate 2 is made of a material such as aluminum and has fine irregularities with a satin finish on the side of the polarizing plate 24.
5 is provided, and this support plate 25 supports the polarizing plate 24 and the glass plate 1 within the horizontal plane of XY. Support plate 2
5 is moved by the XY table 2, and this support plate 25 supports the glass plate 1 and the polarizing plate 24 horizontally without distortion. The matte surface of the support plate 25 may be black or white, or may be colored in another color.

As another embodiment of the present invention, the support plate 25 may be a mirror whose reflective surface is on the polarizing plate 24 side. When the support plate 25 is a mirror, the reflected light from the light source 23 is directly incident on the imaging means 4. In order to avoid this, it is necessary to consider the position of the reflective surface imaging means 4 of the support plate 25 or the light source 23.

By using the polarizing plate 24, the reflected light from the light source 23 is reliably prevented from directly entering the imaging means 4, and thereby the transparent electrode formed on the glass plate 1 can be detected by the imaging means 4 in multiple gradations. It is possible to take an image in the same manner as in the above-mentioned embodiment.

The number of polarizing plates 24 may be one as shown in FIG. 7, or a plurality of polarizing plates whose polarization directions are shifted by, for example, 90 degrees may be used. The other configurations are similar to those of the previous embodiment.

FIG. 8 is a simplified system diagram of yet another embodiment of the present invention. The imaging means 26 includes a line image sensor including an objective lens 27 and a charge-coupled device 28, and images a partial area 30 of the liquid crystal display device 29 from above.

These two liquid crystal display devices have a structure in which a space for enclosing liquid crystal is maintained between a pair of glass plates each having a transparent electrode formed thereon by an intervening piece made of synthetic resin beads. It is possible to image each imaging area 30 by the imaging means 26, count the number of intervening pieces in the imaging area 30, and inspect whether the intervening pieces are evenly distributed and arranged. As described above, this intervening piece is made of synthetic resin and has translucency, shines brightly with the light from the irradiation end 31, and can be distinguished from the glass plate and the transparent electrode. The imaging area 30 is, for example, 1 mm long and 1 mm wide.
mm area, and the size of two liquid crystal display devices is 1 m in length.
, and has a width of 1 m, and the intervening piece is this liquid crystal display device 2.
They are distributed and arranged over the entire surface of 9. Irradiation end 31
is connected to an optical fiber 32, into which light from a light source 33 is guided. Light from light source 33 is also directed into optical fiber 34.

The liquid crystal display device 29 is placed on an X-Y table 35,
It moves in a horizontal plane, and thus a plurality of imaging areas 30 can be selectively imaged by the imaging means 26. The output of the imaging means 26 is given to an image processing device 36, where calculations similar to those in the previous embodiment are performed to count the number of intervening pieces, and the calculation results can be displayed using a cathode ray tube 37 or the like. can.

FIG. 9 is a sectional view of the vicinity of the objective lens 27 of the imaging means 26, and FIG. 10 is a bottom view of the vicinity of the objective lens 27 of the imaging means 26. Referring to these drawings, light from the light source 33 via the optical fibers 3 and 1 passes through the objective lens 27.
The optical path 45 formed on the outer periphery of the mirror advances as indicated by reference numeral 38, and the tapered reflective surfaces 40 of the three reflective members
reflected by the imaging area 3 as indicated by reference numeral 41.
Focused on 0. The reflective member 39 has a concave reflective surface such as a parabola. In this way, the imaging area 30 is illuminated with high illuminance. The reflected light from the imaging area 30 is reflected by the objective lens 27.
is guided from the optical path 42 to the charge-coupled device 28 via the optical path 42 .

The objective lens 27 is attached to an inner tube 43, and an optical path 45 through which light 38 passes is formed between the inner tube 43 and the outer tube 44. The outer cylinder 44 is fixed to the inner cylinder 43 by a connecting piece 46.

FIG. 11 shows an image of the imaging area 30 taken by the imaging means 26. As shown in FIG. The interval d5 in the Y direction between the scanning lines 47 in the X direction is selected to be smaller than the diameter d4 of the intervening piece 46, which is a bead of the liquid crystal display device 29, so that the intervening piece 46 can be accurately detected by the plurality of scanning lines 47. be able to.

In order to reliably detect the intervening piece 46 of the liquid crystal display device 29, a polarizing plate 48 and a polarizing plate 48 are provided on the side opposite to the irradiation end 31 of the two liquid crystal display devices (lower side in FIG. 8) in the same way as in the previous embodiment. ,
Four matte support plates may also be provided.

FIG. 12 shows the experimental results of the inventor. Support plate 49
is made of aluminum and has a black-dyed satin finish. When the polarizing plate 48 is omitted, a waveform containing noise during scanning in the X direction as shown in FIG. 12 (1) is obtained; When only one polarizing plate is used, the waveform shown in FIG. 12 (2) is obtained, and two polarizing plates 4 whose polarization directions are shifted by 90 degrees from each other
8, the waveform shown in FIG. 12 (3) was obtained. Pulses pi, p2 . p3 is obtained, and pulse p3 is pulse p3.
It can be seen that it is possible to detect the intervening piece 46 more clearly than in case 1.

In this way, the processing device 36 can detect the intervening piece 46 by level-discriminating the output level corresponding to the light intensity of the charge-coupled device 28 using a predetermined discrimination level.

FIG. 13 shows the i-tip plate 48 showing the experimental results of the present inventor.
Two sheets are used whose polarization directions are shifted by 90 degrees from each other, and the support plate 49 is made of aluminum and has a satin finish. With this configuration as well, pulses p4 corresponding to the two intervening pieces 46 of the liquid crystal display device can be obtained.

FIG. 14 shows other experimental results of the inventor.

In this embodiment, when the polarizing plate 48 is omitted and the support plate 35 is a mirror, FIG. 14(1) is obtained.

According to such a configuration, the intervening piece 4 of the liquid crystal display device 29
A pulse p5 containing noise corresponding to 6 is obtained. Furthermore, as shown in FIG. 14 (2), two polarizing plates 48 whose polarization directions are shifted by 90 degrees from each other are used, and the support plate 48 is
When a mirror is used as 9, a pulse p6 corresponding to the two intervening pieces 46 of the liquid crystal display device is obtained.

Based on the experimental results shown in FIGS. 12 to 14, when a polarizing plate is used, the detection of the intervening piece 46 of the liquid crystal display device 29 is reduced by the output of the charge coupled device 28, regardless of the surface condition of the support. It turns out that this is possible by level discrimination.

The present invention can be implemented not only in connection with a liquid crystal display device, but also in a wide range of technical fields for detecting a transparent object provided on a transparent plate. .

Effects of the Invention As described above, according to the present invention, it is possible to automatically and accurately detect a light-transmitting object provided on a light-transmitting plate-like body in a short time, and this invention is not related to the prior art described above. This eliminates the need for skilled workers as described above.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram of an embodiment of the present invention, FIG. 2 is a plan view of a glass plate 1, FIG. 3 is a diagram showing the imaging situation of this glass plate 1, and FIG. FIG. 5 is a flowchart for explaining the operation of the arithmetic circuit 8; FIG. 6 is a diagram illustrating the arithmetic operation of the arithmetic circuit 8; FIG. is a simplified perspective view of another embodiment of the present invention, FIG. 8 is a simplified system diagram of still another embodiment of the present invention, and FIG. 9 is a diagram showing the imaging means 2.
10 is a bottom view of the vicinity of the objective lens 27 of the imaging means 26, FIG. 11 is a diagram showing an image of the imaging region 30 imaged by the imaging means 26, and FIGS. FIG. 14 is a diagram showing experimental results by the inventor of the present invention for the embodiment shown in FIGS. 8 to 11. 2.19...X-Y table, 3.23...Light source, 4
．． 26... Imaging means, 5... Analog-to-digital conversion circuit, 6... Image processing circuit, 7... Memory, 8...
...Arithmetic circuit, 12...Transparent electrode, 14, 15.16
...Scratch, 24.48...Polarizing plate, 25.49...
Support plate, 29...Liquid crystal display device, 30...Imaging area agent Patent attorney Keishi Saikyo /P1 ~P2 11.ノ・−１′−P＾−躠ν・４−・〜、−J−′−
″゛＼／−＋＋＋４＋−１、＾λ−Jo+、He、−１gin−
Ri-Iichi--Rho Kidney--〇〜o9〜P3

Claims (4)

[Claims] (1) A light source that transmits light through a translucent plate and a translucent object provided thereon, and an image of the translucent plate and the translucent object on the side opposite to the light source. means for storing an image taken by the imaging means of a light-transmitting plate on which a normal light-transmitting object is provided; and a light-transmitting board on which a light-transmitting object to be inspected is provided. A translucent device characterized by comprising: arithmetic means for determining the difference between the output of the imaging means that images the object and the content of the storage means; and means for determining the level of the difference in response to the output of the arithmetic means. Sexual object detection device. (2) A light source that irradiates the light-transmitting plate and the light-transmitting object provided thereon, and imaging the light-transmitting plate and the light-transmitting object on the same side as the light source. means for storing an image taken by the imaging means of a light-transmitting plate on which a normal light-transmitting object is provided; and a light-transmitting board on which a light-transmitting object to be inspected is provided. A translucent device characterized by comprising: arithmetic means for determining the difference between the output of the imaging means that images the object and the content of the storage means; and means for determining the level of the difference in response to the output of the arithmetic means. Sexual object detection device. (3) A light-transmitting object detection device according to claim 2, characterized in that the light-transmitting plate-like body is supported via a polarizing plate on the opposite side of the plate-like body from the light source. . (4) A light source that irradiates light to the translucent plate and the translucent object provided thereon, and images the translucent plate and the translucent object on the same side as the light source. means for level-discriminating the output of the imaging means; a polarizing plate disposed on the opposite side of the plate-like body from the light source; and a polarizing plate disposed on the opposite side of the plate-like body with respect to the polarizing plate, the surface of which is satin-finished. and a means for supporting a polarizing plate.