WO2006088150A1

WO2006088150A1 - Glass substrate inspection equipment and inspection method

Info

Publication number: WO2006088150A1
Application number: PCT/JP2006/302865
Authority: WO
Inventors: Shinichi Okamura
Original assignee: Central Glass Company, Limited
Priority date: 2005-02-17
Filing date: 2006-02-17
Publication date: 2006-08-24
Also published as: KR100898208B1; KR20070085606A; JP4747602B2; JP2006226801A

Abstract

Inspection equipment for a glass substrate being employed in a flat panel display, the glass substrate subjected to cutting at the corner and boring of a through hole, characterized by comprising a stopper provided in the middle of a glass substrate carrier, for stopping the glass substrate at a predetermined position, an image capturing unit consisting of an illuminator on a line being arranged perpendicularly to the carrying direction of the glass substrate and directed from one side of the stopped glass substrate, and a camera provided oppositely to the illuminator across the glass substrate, directed in the direction perpendicular to the carrying direction of the glass substrate and movable in parallel therewith with its optical axis kept perpendicular to the glass substrate, and an image processor for processing the images of the cut at the corner of the glass substrate and the through hole.

Description

Specification

Glass substrate inspection apparatus and inspection method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a glass substrate inspection apparatus used for a flat panel display, and more particularly to an inspection apparatus and an inspection method for performing dimensional inspections for hole processing and notch processing of a glass substrate using a camera and an image processing apparatus.

Background of the Invention

[0002] A glass substrate used in a flat panel display such as a liquid crystal display or a plasma display has a shape in which a glass plate is cut into a rectangle and a corner of the glass plate called an orientation flat is cut out. The through hole has a hole force at a position close to.

[0003] In such a glass substrate, if the size and shape of the notch and the position of the through hole are not as desired, problems may occur during assembly of the display, and the through hole If there are defects on the edge, such as cracks or chips, the glass substrate will be damaged, causing problems.

[0004] For this reason, the size and shape of the notch, the position of the through-hole, and the presence or absence of defects near the through-hole edge with respect to the cut-out and through-hole processed parts on the glass substrate. Need to be checked.

[0005] Patent Document 1 discloses a technique for optically inspecting a shape 'dimension. The purpose of this optical system is to recognize the shape, and it is difficult to detect defects.

[0006] As an inspection apparatus for a glass substrate, the glass plate is illuminated by an illuminator disposed obliquely with respect to the traveling direction of the glass plate, and the glass plate is illuminated by a line camera having a visual field parallel to the illuminator. Patent Document 2 discloses an apparatus for detecting the defect of the cut portion of the glass plate by detecting the light of the formed portion.

[0007] In addition, the glass plate is fixed to a stage that can move and rotate, the glass substrate is fiber-illuminated at various angles, and images are taken with a CCD camera from a direction perpendicular to the glass substrate and an oblique direction. Patent Document 3 discloses an apparatus for detecting a defect of a glass substrate by performing binary processing on the result. [0008] In the devices disclosed in Patent Documents 2 and 3, it is difficult to inspect the shape of a notch called an orientation flat even though various defects existing on the substrate can be detected.

[0009] Further, for the light-transmitting sheet, in Patent Document 4, a moving light-transmitting sheet is imaged with a line camera, and a hole in the light-transmitting sheet is detected as a defect in the light-transmitting sheet. The method is disclosed.

[0010] In this method, even if the position and size of a hole as a defect can be grasped, the dimensional accuracy of the position and size of the processed through hole and the defect of the edge of the through hole cannot be inspected. Have difficulty.

Patent Document 1: JP-A-6-137815

Patent Document 2: JP-A-11-169343

Patent Document 3: Japanese Patent Laid-Open No. 2003-98122

Patent Document 4: Japanese Patent Application Laid-Open No. 11-304724

Summary of the Invention

[0011] In the conventional inspection apparatus, the illumination method and the image processing are different in the inspection of the shape 'dimension and the inspection of the defect, and the notch or the through hole of the glass substrate used for the flat panel display is different. The shape inspection and the inspection of defects that occur at the edge of the through hole must be performed by separate devices, and the inspection of notches and through hole shapes and the inspection of defects that occur at the edge of the through hole are performed with one device. It was difficult.

[0012] The present invention inspects a notch and a hole shape determined by a design specification and a defect generated at an edge of a through hole naturally generated by processing of the through hole with a single inspection device. The issue is to provide an inspection device.

[0013] A glass substrate inspection apparatus of the present invention is a glass substrate inspection apparatus used for a flat panel display, wherein the glass substrate is notched in a corner portion and processed in a through hole. A stopping device that stops the glass substrate at a predetermined position in the middle of the conveying device that conveys the glass substrate, and one surface force of the stopped glass substrate A straight line that is arranged perpendicular to the conveying direction of the glass substrate An upper illuminator and an optical axis that is provided on the opposite side of the illuminator across the glass substrate and is movable in parallel to the glass substrate in a direction perpendicular to the conveyance direction of the glass substrate. With the camera pointed vertically Glass substrate inspection, comprising: an image capturing device that captures an image of a corner notch and a through-hole of the glass substrate captured by the image capturing device. Device.

Brief Description of Drawings

FIG. 1 is a plan view schematically showing a glass substrate.

FIG. 2 is a schematic view showing an inspection apparatus of the present invention.

FIG. 3 is a diagram schematically showing a binarized image of notches.

FIG. 4 is a diagram schematically showing a binarized image of a through hole.

FIG. 5 is a graph showing the size of the dark part numerically indicated at the edge part of the through hole.

Detailed description

[0015] The glass substrate inspection apparatus and inspection method of the present invention provide an apparatus for easily inspecting a glass substrate for a flat panel display, which has been subjected to notch processing and through-hole processing.

[0016] Most glass substrates used in flat panel displays have a rectangular shape. As shown in Fig. 1, the glass substrate has a rectangular corner called an orientation flat so that the front and back sides and orientation of the glass substrate can be distinguished. On the other hand, notches 4, 5, 6, and 7 are processed. In addition, drilling force is provided to provide through holes 2 and 3 to fill the gas. These notches and through-holes are machined into a predetermined position and a predetermined size based on the design specifications of the glass substrate.

[0017] The glass substrate inspection apparatus of the present invention inspects the notch and the shape of the through hole of the glass substrate and the defect of the edge of the through hole, and a stop device for stopping the substrate being conveyed, An image capturing device comprising a scattered light source that illuminates the glass substrate and a camera that images the glass substrate illuminated by the scattered light, and the camera is moved to a predetermined position to image the notch or the through-hole. And an image processing device for analyzing the captured camera image.

FIG. 2 shows an example of the inspection apparatus of the present invention. The glass substrate 1 is moved by the transport roll 8 in the direction indicated by the arrow in the figure, and the inspection is performed by stopping the glass substrate 1 with a stop device (not shown). [0019] The stop device stops the glass substrate 1 when the notch or the through hole comes to the position of the camera 9 in the transport direction. The stop device may use an optical glass substrate edge detection device to automatically stop the transport roll 8 and stop the glass substrate based on a signal for detecting the edge of the glass substrate 1. Alternatively, a physical stop object may be used so that the glass substrate stops by stopping the transport roll 8 when the glass comes into contact with the stop object. The physical stop object should be able to be taken in and out after the inspection is completed so that it can be transported by the transport roll again.

As shown in FIG. 2, the scattered light source 10 that illuminates the stopped glass substrate 1 with the scattered light 13, and the scattered light 13 is installed on the side that transmits the glass substrate 1, and is illuminated with the scattered light 13. The image of the glass substrate 1 is captured using an image capturing device including a camera 9 for imaging the glass substrate 1.

[0021] It is preferable to use an area camera as the camera 9 for imaging notches and through-holes in the glass substrate 1 stopped by the stopping device. Furthermore, it is preferable to use a telecentric lens so that the side surface of the through hole is not captured when imaging the through hole.

[0022] The glass substrate 1 stopped by the stopping device is illuminated from below by a linear illuminator 15, and the through hole and corner cutout of the glass substrate 1 are imaged by the camera 9 above the glass substrate 1. .

[0023] The illuminator is composed of a scattered light source 10 and a box cover 11, and it is desirable to use a straight fluorescent lamp as the scattered light source 10, but other light sources can be used as long as they can be illuminated with scattered light. Good. Further, in order to make the illumination of the scattered light 13 uniform, it is preferable to provide a diffusion plate 14 between the scattered light source 10 and the glass substrate 1.

The camera 9 is installed so that the optical axis of the camera 9 is perpendicular to the glass substrate 1.

Further, the camera 9 can be moved parallel to the glass substrate in a direction perpendicular to the conveyance direction of the glass substrate by the conveyance roll 8 by a moving device (not shown). Instead of fluorescent lamp 11, use a spot illuminator that can move in conjunction with camera 9.

An image captured by the camera 9 shown in FIG. 2 is binarized into bright and dark by the image processing device 12, and the binarized image is used to form the shape of the notch or the through hole. Inspection and inspection of defects at the edge of the through hole are performed. As shown in FIG. 3, the cutout image 20 has corners cut out to form an oblique edge 22. Many glass substrates have a chamfer 21 processed, and the chamfer 21 is displayed as dark in the cutout image 20.

[0027] From the image of the notch, for example, the shape inspection of the notch can be performed as follows.

[0028] Intersection PI, P2 coordinates of edge line 22 of notch and non-notch edge line 23 and edge line 24, and coordinates of intersection P3 of extension line of edge line 23 and edge line 24 The triangles Pl, P2, and P3 are measured, and the size and shape of the notch are obtained. Compared with the values in the design specifications, it is possible to judge whether the difference is below the allowable force or not. .

Furthermore, in the glass substrate inspection apparatus of the present invention, the width of the chamfer 21 can be measured, and the chamfered shape inspection can be performed.

[0030] FIG. 4 is an image of the through hole 30. The glass substrate 1 is stopped by a stop device in the glass substrate transport direction so that the through hole 30 is directly below the camera 9, and the camera 9 is moved. Obtained by imaging through-hole 30.

[0031] In order to satisfactorily inspect the through hole, it is desirable to match the center P4 of the through hole 30 with the optical axis of the camera 9.

[0032] For this reason, the glass substrate 1 is supported by a suction support device including a suction cup or a suction pad, and the suction support device is supported by a moving device including a servo motor or a pulse motor and a motor controller. It is preferable to provide a moving device that can move with high accuracy.

The glass substrate inspection apparatus of the present invention is configured such that the movement of the camera 9 can be moved in parallel to the glass substrate 1 in a direction perpendicular to the transport direction. Furthermore, it is preferable to provide a moving device that allows the camera 9 to move in parallel with the glass substrate 1 in the same direction as the conveyance direction of the glass substrate 1 and to move in the direction perpendicular to the glass substrate 1. .

[0034] The center of the through hole 30 and the optical axis of the camera 9 are obtained by determining the position of the through hole 30 in the image of the camera 9 by image processing, and based on the position of the through hole 30, the camera 9 and the Z or glass substrate It can be matched by one mobile device. The vicinity of the edge of the through hole 30 appears as a dark portion 31 in the image. Defective edge of through hole 30

32 also appears dark in the image. The camera is installed perpendicular to the glass substrate, and detection is possible regardless of which side of the glass substrate the defect is on.

[0036] The inspection of the shape of the through hole 30 and the inspection of defects can be performed as follows, for example.

[0037] The coordinates of the center P4 of the through hole 30 and the radius rl of the through hole 30 are also measured by the image data force, and the quality and position of the through hole 30 are inspected based on the difference from the design specification value. .

[0038] Furthermore, defects called cracks or chips may occur at the edge of the through hole 30 due to the processing of the through hole 30. Such a defect appears in the image as a dark part 32 that is larger than the dark part 31 of the non-defective edge in the image.

[0039] An edge defect of the through hole 30 can be detected as follows.

[0040] In the image of the through hole 30, a reference line is hypothesized in an appropriate direction parallel to the surface of the glass substrate from the center P4 of the through hole, and the reference line is rotated clockwise on the glass substrate surface. . For the rotation angle Θ, the image power is also measured for the dark part width t near the edge.

Θ

Create a graph.

[0041] The width t of the dark part of the defect is larger than the width t of the dark part of the non-defective edge.

twenty one

It is possible to determine the quality of edge processing using.

[0042] Note that in capturing an image of the through hole 30, a light shielding plate (not shown) is provided between the diffusion plate 14 and the glass substrate 1, and the width of illumination illuminated with the scattered light 13 on a straight line is It is preferable to set the field of view of camera 9 to 1.5 to 3 times, more preferably about 2 times.

[0043] If the illumination width of the scattered light 13 is larger than 3 times the field of view of the camera 9, the brightness of the image of the defect becomes brighter, making it difficult to distinguish by binary values. There is a risk that the illumination will be reflected in the entire field of view of the camera 9, illumination unevenness may occur, and the inspection accuracy may soon decrease.

Claims

The scope of the claims

[1] A glass substrate inspection apparatus used for a flat panel display, in which the glass substrate is notched in a corner portion and a hole is formed in a through hole, and is in the middle of a conveying device that conveys the glass substrate. A stop device for stopping the glass substrate at a predetermined position, a linear illuminator disposed at right angles to the conveying direction of the glass substrate from one surface force of the stopped glass substrate, Provided on the opposite side of the illuminator across the glass substrate, the optical axis is perpendicular to the glass substrate, and can be moved parallel to the glass substrate in a direction perpendicular to the glass substrate transport direction. An image capturing device comprising a camera and an image processing device for processing an image of a corner notch and a through-hole of the glass substrate captured by the image capturing device. Glass substrate inspection apparatus.

[2] The glass substrate inspection apparatus according to [1], wherein the size and shape of the notch are inspected using the binary-processed image of the notch.

[3] The glass according to claim 1 or 2, wherein a defect of an edge of the through hole is inspected using a binary image of the through hole. Board inspection equipment.

[4] A support device for sucking and supporting the glass substrate and a moving device for moving the support device in the transport direction and Z or a direction perpendicular to the transport direction are provided at the stop position of the glass substrate. The glass substrate inspection apparatus according to claim 1.

5. The glass substrate inspection apparatus according to claim 1, further comprising a moving device for moving the camera in the transport direction and in a Z direction or a vertical direction of the glass substrate.

[6] Using the glass substrate moving device and the Z or camera moving device, align the optical axis of the camera with the center of the through hole, capture the image of the through hole, and detect the through hole using the image. A glass substrate inspection method using the glass substrate inspection apparatus according to claim 1, wherein:

[7] Inspection capability for defects at the edge of the through-hole The circular edge of the through-hole and the dark area around the edge are made “dark” by binary image processing, and the edge of the edge is perpendicular to the circular edge of the through-hole. 6. A glass substrate inspection method using the glass substrate inspection apparatus according to claim 1, wherein the dark portion is measured and the through hole is inspected using the measured length of the dark portion.