JP3779507B2 - Inspection device for transparent laminate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inspection apparatus for inspecting the appearance of a transparent laminate such as an LCD (liquid crystal display).
[0002]
[Prior art]
Conventionally, as an inspection device for inspecting the appearance of transparent or translucent transparent laminates such as LCDs, the transparent laminate is illuminated with a lamp by a method such as coaxial epi-illumination, oblique illumination, or transmission illumination. In addition, there has been an apparatus for inspecting appearance such as contamination of foreign matter by taking an image of the transparent laminate with an imaging device such as a video camera and observing an image of the transparent laminate displayed on a monitor screen. As the foreign matter, glass cullet, fiber chips, bubbles, adhesives, or the like, which are fine glass fragments, can be considered.
[0003]
[Problems to be solved by the invention]
However, in such a conventional inspection apparatus, there is a problem that even if the presence of the foreign matter itself can be found, it cannot be determined between which layer of each transparent body the foreign matter is included in the transparent laminate. .
[0004]
For example, in the case of an LCD, in order to protect the polarizing plate, a protective film such as a resin sheet is attached to the surface of the polarizing plate at least until the shipment stage from the factory. Therefore, even if foreign matter is mixed in the surface of the protective film or between the protective film and the polarizing plate, the foreign matter is not present inside the LCD and must be judged as a good product. However, since the conventional inspection apparatus cannot determine whether the foreign matter is present inside the LCD or the foreign matter, there is no foreign matter between the protective film surface or the protective film and the polarizing plate. There is an inconvenience that it is determined as a defective product until it must be determined as a non-defective product, as in the case of mixing.
[0005]
The present invention has been conceived under such circumstances, and it is possible to know which layer of a plurality of transparent bodies constituting a transparent laminated body contains foreign matter. The problem is to provide an inspection device.
[0006]
DISCLOSURE OF THE INVENTION
In order to solve the above problems, the present invention takes the following technical means.
[0007]
According to the first aspect of the present invention, there is provided an inspection apparatus for imaging a transparent laminate in which sheet-like transparent bodies are laminated, and inspecting the transparent laminate based on an image obtained by imaging, A laser device that emits a laser beam that is transmitted obliquely with respect to the stacking direction of the transparent body from one main surface to the other main surface of the transparent layered body, and one main surface of the transparent layered body Obtained by an imaging device that captures an image from the side, a transfer device that sequentially changes the transmission position of the transparent laminate by laser light by relatively moving the laser device, the imaging device, and the transparent laminate, and the imaging device Based on the image data, one main surface and the other main surface of the transparent laminate, and each image data of the laminate boundary surface of each transparent body are separated and accumulated, so that one main surface and the other of the transparent laminate The main surface of each and the lamination of each transparent body Characterized by comprising an image data processing means for enabling generate an image of the surface inspection apparatus of the transparent laminate is provided.
[0008]
The transparent body constituting the transparent laminate may be completely transparent or translucent.
[0009]
An LCD can be considered as the transparent laminate, but is not limited thereto.
[0010]
The image of the transparent body surface generated by the image data processing means may be an image of one transparent body surface, or may be an image of a plurality of transparent body surfaces. Of course, in the case of a plurality of transparent body surface images, they are individually generated and can be individually displayed on a monitor screen.
[0011]
According to a preferred embodiment, the image data processing means includes: a linear bright portion due to irregular reflection of laser light on one main surface of the transparent laminate, and the other of the transparent laminate, of the images obtained by the imaging device. The position of the linear bright portion due to the irregular reflection of the laser beam at the laminated boundary surface of each transparent body is determined by the distance from the reference position to the linear bright portion due to the irregular reflection of the laser beam on the main surface of to decide.
[0012]
According to another preferred embodiment, two sets of a laser device and an imaging device are provided, and the two laser devices are inclined in directions opposite to each other with respect to the stacking direction of the transparent body. Laser light transmitted through the transparent laminate is emitted, and laser light is emitted alternately at different timings.
[0013]
As described above, the image data processing means separates the image data of one main surface and the other main surface of the transparent laminate and the lamination boundary surface of each transparent member based on the image data obtained by the imaging device. By accumulating, it is possible to generate images of one main surface and the other main surface of the transparent laminate, and the lamination boundary surface of each transparent member, so that the appearance of the image of the desired transparent member is individually inspected. By this, it can be known which foreign substance exists between which of the some transparent body which comprises a transparent laminated body.
[0014]
Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 2 is a schematic configuration diagram of a transparent laminate inspection apparatus according to the present invention. This inspection apparatus transfers a LCD 1 as a transparent laminate in the direction of arrow A, and a laser beam transmitted through the LCD 1. A laser device 3 that emits light 3a, an imaging device 4 that images irregularly reflected light of the laser beam 3a by the LCD 1, a laser device 5 that emits laser light 5a that passes through the LCD 1, and an imaging device that images irregularly reflected light of the laser beam 5a by the LCD 1 6. Control device 7 for controlling laser devices 3 and 5 and imaging devices 4 and 6 and processing images taken by imaging devices 4 and 6, and projecting images processed by control device 7 on a monitor screen The monitor device 8 is provided. The LCD 1 is supported by a pair of support plates 2 a and 2 b that protrude from the upper surface of the transfer device 2. Although not shown, the control device 7 includes a CPU (central processing unit), a RAM (random access memory), and the like.
[0017]
FIG. 3 is a plan view of the LCD 1, and the laser beam 3 a and the laser beam 5 a are linear over the entire length in the width direction of the LCD 1 at the position of one main surface of the LCD 1. That is, the laser device 3 and the laser device 5 are provided with a collimator lens and an aspherical cylinder lens (not shown), respectively, and radiate the laser beam 3a and the laser beam 5a spreading in a fan shape. These laser beams 3a and 5a are, for example, visible light having a wavelength of 635 nm, and the line width on one main surface of the LCD 1 is 30 μm.
[0018]
FIG. 1 is a schematic cross-sectional view of the LCD 1, and the LCD 1 includes a first transparent plate 1a, a second transparent plate 1b, and a third transparent plate 1c. The actual LCD is composed of more transparent plates, but here it is assumed that it is composed of three layers of transparent plates for easy understanding of the explanation. The first transparent plate 1a corresponds to a protective film stuck at least to the shipping stage from the factory to protect the polarizing plate, the second transparent plate 1b corresponds to the polarizing plate, and the third transparent plate 1c It corresponds to other members such as a glass substrate and a liquid crystal layer.
[0019]
The laser beam 3a from the laser device 3 is transmitted through the LCD 1 at an angle θ with respect to the stacking direction of the LCD 1. In this embodiment, the angle θ is 45 degrees. Although not shown in FIG. 1, the laser beam 5a from the laser device 5 is transmitted through the LCD 1 at an angle θ with respect to the stacking direction of the LCD 1. In this embodiment, the angle θ is 45 degrees. is there. However, the laser beam 3a and the laser beam 5a are inclined 45 degrees in directions opposite to each other with respect to the stacking direction of the LCD 1.
[0020]
When the laser beam 3a is transmitted through the LCD 1, a point B that is a boundary surface between the air layer and the first transparent plate 1a, a point C that is a boundary surface between the first transparent plate 1a and the second transparent plate 1b, a second point The laser beam 3a is irregularly reflected at point D, which is a boundary surface between the transparent plate 1b and the third transparent plate 1c, and point E, which is a boundary surface between the third transparent plate 1c and the air layer. Therefore, the image picked up by the image pickup device 4 appears as four bright lines, that is, linear bright portions B, C, D, and E, on the monitor screen 8a of the monitor device 8, as shown in FIG. The linear bright portion B corresponds to the irregular reflection at the point B, and the linear bright portion C corresponds to the irregular reflection at the point C. Further, the linear bright portion D corresponds to irregular reflection at the point D, and the linear bright portion E corresponds to irregular reflection at the point E.
[0021]
Here, since the laser beam 3a makes an angle of 45 degrees with respect to the laminating direction of the LCD 1, the thicknesses of the first transparent plate 1a, the second transparent plate 1b, and the third transparent plate 1c are set to t ₁ and t ₂ , respectively. , T ₃ , the horizontal distance between point B and point C, that is, the separation distance in the direction orthogonal to the stacking direction of LCD ₁ is t ₁ , the horizontal distance between point C and point D is t ₂ , and point D and point E are The horizontal distance of is t ₃ . Therefore, when a telecentric optical system is used, the distance L ₁ between the linear bright part B and the linear bright part C on the monitor screen 8a of the monitor device 8, and the linear bright part C and the linear bright part D the distance L _2, the ratio of the distance L ₃ between the linear bright portion D and the linear bright portion E is equal to the ratio t ₁ and t ₂ and t _3. In the case of a macro optical system, correction is performed according to the distance. That is, calibration is performed. As a result, even if the linear bright portions B, C, D, and E are displaced as a whole on the monitor screen 8a as a whole, the linear bright portions B and the linear bright portions E are used as a reference. The positions of the bright portions C and the linear bright portions D can be accurately known.
[0022]
The above description holds true for the laser beam 5a from the laser device 5 in the same manner as the laser beam 3a from the laser device 3.
[0023]
Next, the operation will be described. The LCD 1 transported at a predetermined speed in the direction of arrow A by the transport device 2 is irradiated with laser light 3 a and laser light 5 a by the laser device 3 and the laser device 5. The laser light 3a and the laser light 5a are transmitted through the LCD 1, and the light due to irregular reflection at this time is picked up by the image pickup device 4 and the image pickup device 6 and stored as image data in a RAM built in the control device 7. Of course, imaging is performed in an environment where light from light sources other than the laser beams 3 a and 5 a is not captured by the imaging devices 4 and 6. At this time, the laser device 3 and the laser device 5 alternately emit laser light 3a and laser light 5a at different timings, and in synchronization with those timings, the imaging device 4 emits irregularly reflected light from the laser light 3a. The imaging device 6 images the irregularly reflected light from the laser light 5a.
[0024]
As the LCD 1 is transferred by the transfer device 2, the transmission position of the LCD 1 is sequentially displaced by the laser light 3 a and the laser light 5 a, and the LCD 1 is moved by a predetermined distance, whereby the image pickup device 4 and the image pickup device 6 over the entire LCD 1. Imaging is performed. For example, since the line width of the laser beam 3a and the laser beam 5a is 30 μm, if the imaging device 4 and the imaging device 6 capture one frame every time the LCD 1 is moved by 30 μm, the entire LCD 1 is captured without omission. Will be.
[0025]
The image data stored in the RAM of the control device 7 is processed by a CPU built in the control device 7, and images of the linear bright portions B, C, D, and E are individually generated. That is, among the image data for one frame, the image data of the linear bright portions B, C, D, and E are individually taken out, and the image data are individually stored in a predetermined area of the RAM. At this time, the position of the linear bright part B and the linear bright part E is determined by the CPU based on the image data for each frame, and the linear bright part is determined based on the amount of displacement from the reference position using these positions as the reference position. The positions of the part C and the linear bright part D are determined. This is because it is difficult to completely ideally transfer the LCD 1 by the transfer device 2, and as a result of the LCD 1 irregularly displacing irregularly during the transfer, it is linear on the image pickup devices of the image pickup device 4 and the image pickup device 6. Since the bright portions B, C, D, and E are minutely displaced integrally, in order to accurately determine the positions of the linear bright portion C and the linear bright portion D while avoiding the influence of the minute displacement, the linear portions The positions of the bright part B and the linear bright part E are used as a reference. In this way, not only the influence due to the transfer of the LCD 1 but also the influence due to the minute undulation of the LCD 1 itself can be reduced as much as possible.
[0026]
Thus, by separately separating and accumulating the image data of the linear bright portions B, C, D, and E for each frame, an image of the boundary surface between the air layer and the first transparent plate 1a, that is, one main surface of the LCD 1 is displayed. An image of a boundary surface between the first transparent plate 1a and the second transparent plate 1b, an image of a boundary surface between the second transparent plate 1b and the third transparent plate 1c, and the third transparent plate 1c and the air layer The boundary surface, that is, the image of the other main surface of the LCD 1 can be individually displayed on the monitor screen 8 a of the monitor device 8. Therefore, when a foreign object exists on any boundary surface, the foreign object is displayed only on the image of the boundary surface. Since the irregular reflection due to the foreign matter is sufficiently larger than the irregular reflection due to the boundary surface without the foreign matter, the foreign matter can be clearly recognized from the image.
[0027]
For example, as shown in FIG. 5, when the foreign material 11 exists on the boundary surface between the second transparent plate 1b and the third transparent plate 1c, an image of the boundary surface between the second transparent plate 1b and the third transparent plate 1c is displayed. When projected on the monitor screen 8a of the monitor device 8, the foreign matter 11 is projected as shown in FIG. Therefore, the shape of the foreign matter 11 can be determined, for example, the foreign matter 11 is fibrous. Incidentally, in FIG. 6, D _1, D _n is D ₁ point of FIG. 5, a linear bright portion by the laser beam 3a at the D _n points, and the second transparent plate 1b by a set of these linear bright portion first An image of the boundary surface with the 3 transparent plate 1c is formed.
[0028]
Thus, since the images on the respective boundary surfaces of the LCD 1 can be individually displayed, the appearance inspection of the LCD 1 can be accurately performed. That is, if foreign matter exists in the image of the boundary surface between the air layer and the first transparent plate 1a, or the image of the boundary surface between the third transparent plate 1c and the air layer, the foreign matter can be removed by cleaning, It can be determined that the LCD 1 is a non-defective product. If there is foreign matter in the image of the boundary surface between the first transparent plate 1a and the second transparent plate 1b, the foreign matter can be removed by removing and cleaning the first transparent plate 1a, which is a protective film. It can be judged that. If there is a foreign object in the image of the boundary surface between the second transparent plate 1b and the third transparent plate 1c, it is a foreign object in the LCD 1 and cannot be removed by cleaning, so the LCD 1 is a defective product. It can be judged. In other words, only the image of the boundary surface between the second transparent plate 1b and the third transparent plate 1c is visually inspected, and if there is a foreign object, it can be determined as a defective product, and if there is no foreign material, it can be determined as a non-defective product.
[0029]
Further, the laser device 3 and the laser device 5 are used to radiate the laser light 3a and the laser light 5a from different directions, and the irregularly reflected light from them is individually imaged by the imaging device 4 and the imaging device 6, so that the imaging The blind spot can be eliminated, and the appearance inspection can be performed more accurately. That is, when only the laser beam 3a is used, for example, when a large foreign object exists on the boundary surface between the air layer and the first transparent plate 1a, the laser beam 3a is blocked by the foreign object, and the lower side than the foreign object. Although a blind spot is formed on the boundary surface of the laser beam, the laser beam 5a can be transmitted through the blind spot portion by using the laser beam 5a, so that an image obtained by processing the image signal from the imaging device 4 and the imaging By observing both the image obtained by processing the image signal from the device 6, the blind spot can be eliminated. Further, since the laser beam 3a is inclined with respect to the laminating direction of the LCD 1, one or more of the linear bright portions B, C, D, and E do not appear at both ends of the LCD 1 in the transfer direction. However, such a blind spot can be eliminated as much as possible by using the laser beam 5a together.
[0030]
Further, since the positions of the linear bright portions C and D are determined based on the positions of the linear bright portions B and E, it is possible to avoid the influence of the irregular minute displacement of the LCD 1 due to the transfer as described above, and it is robust. That is, it is possible to realize an appearance inspection that is resistant to fluctuations.
[0031]
In the above embodiment, the inclination angle θ of the laser beam 3a and the laser beam 5a is set to 45 degrees. However, the inclination angle θ is arbitrary and is preferably about 45 degrees to 60 degrees.
[0032]
In the above embodiment, the image signals of all the pixels of the imaging device built in the imaging device 4 and the imaging device 6 are output. However, the processing speed is increased by outputting the image signals of only necessary portions. You may comprise. For example, when the imaging device is a CCD (charge coupled device), it is configured to extract only the image signal of the part that surely includes the area from the linear bright part B to the linear bright part E by a method such as partial scan. May be.
[0033]
In the above embodiment, the LCD 1 is transferred by the transfer device 2. However, the LCD 1 may be fixed and the laser devices 3, 5 and the imaging devices 4, 6 may be moved. Good.
[0034]
In the above embodiment, the positions of the linear bright portions C and D are determined based on the positions of the linear bright portions B and E. However, the bright lines are detected based on the image data for each frame. The position of the linear bright portions C and D may be determined directly. Alternatively, when the irregular displacement due to the transfer of the LCD 1 can be reduced, it is assumed that the positions of the linear bright portions B, C, D, and E on the imaging device of the imaging devices 4 and 6 are fixed. You may comprise so that the image data in the bright parts B, C, D, and E may be separately separated and accumulated. Further, when the positions of the linear bright portions B and E are not used as a reference in this way, the image data of only the linear bright portions D is separated and accumulated, and the LCD 1 is a non-defective product by the image of only the linear bright portions D. It may be determined whether the product is defective or defective.
[0035]
Moreover, in each said embodiment, although two laser beams 3a and 5a were used, you may use only any one.
[0036]
In each of the above embodiments, an example of performing an appearance inspection of the LCD 1 has been described. However, the transparent laminate inspection apparatus of the present invention is not limited to the LCD 1, and a completely transparent or translucent transparent body is laminated. Automatic visual inspection can be performed on any transparent laminate.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an LCD.
FIG. 2 is a schematic configuration diagram of a transparent laminate inspection apparatus according to the present invention.
FIG. 3 is a plan view of an LCD.
FIG. 4 is an explanatory diagram of a linear bright portion imaged by the imaging device.
FIG. 5 is a schematic cross-sectional view of an LCD in a state where foreign matter exists on a boundary surface.
FIG. 6 is an enlarged explanatory diagram of a state in which a boundary surface on which a foreign object exists is displayed on a display screen.
[Explanation of symbols]
1 LCD
1a 1st transparent plate 1b 2nd transparent plate 1c 3rd transparent plate 2 Transfer device 3 Laser device 3a Laser light 4 Imaging device 5 Laser device 5a Laser light 6 Imaging device 7 Control device 8 Monitor device 8a Monitor screen

Claims (3)

An inspection apparatus for imaging a transparent laminate in which sheet-like transparent bodies are laminated, and inspecting the transparent laminate based on an image obtained by imaging,
A laser device that emits laser light that is transmitted obliquely with respect to the stacking direction of the transparent body from one main surface to the other main surface of the transparent stack,
An imaging device for imaging the transparent laminate from one main surface side thereof;
A transfer device that sequentially changes the transmission position of the transparent laminate by the laser light by relatively moving the laser device and the imaging device and the transparent laminate;
Based on the image data obtained by the image pickup device, one main surface and the other main surface of the transparent laminate, and, by separating and accumulating each image data of the lamination interface of the transparent body, said transparent An inspection apparatus for a transparent laminate, comprising: one main surface of the laminate, the other principal surface, and an image data processing unit that can generate an image of the laminate boundary surface of each transparent member . The image data processing means includes a linear bright portion due to irregular reflection of the laser light on one main surface of the transparent laminate, and the other main surface of the transparent laminate among images obtained by the imaging device. The position of the linear bright part due to the irregular reflection of the laser light at the laminated boundary surface of each transparent body is determined from the linear bright part due to the irregular reflection of the laser light at the reference position and the displacement distance from the reference position The inspection device for a transparent laminate according to claim 1. Two sets of the laser device and the imaging device are provided,
The two laser devices emit laser beams that pass through the transparent laminated body while being inclined in directions opposite to each other with respect to the lamination direction of the transparent bodies, and alternately emit laser beams at different timings. The transparent laminate inspection apparatus according to claim 1, wherein the transparent laminate is radiated.

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