JP2012225824A - Method and apparatus for inspecting three-dimensional defect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional defect inspection apparatus which is an automatic defect inspection apparatus of a color filter substrate and is capable of performing extremely efficient defect inspection of a defect on the color filter substrate by performing not only area size determination of a plane but also simultaneously performing defect determination in a height direction.SOLUTION: The three-dimensional defect inspection apparatus for simultaneously detecting defects in a plane direction and a height direction of the color filter substrate includes: conveyance means for placing the color filter substrate and conveying the color filter substrate on an XY plane; imaging means in which a camera and a light source can be synchronously and axially moved on the color filter substrate; image processing means for performing arithmetic processing of imaged data obtained by the imaging means; and means for determining acceptance of the color filter substrate by three-dimensional defect data obtained by the image processing means.

Description

  The present invention relates to a defect inspection method for a color filter for a liquid crystal display device, and more particularly to a method for automatically determining the defect type in an automatic inspection machine.

  In general, a color filter substrate for a liquid crystal display device includes, for example, a black matrix (BM: light-shielding portion) 15 formed by pattern etching of a chromium or chromium oxide film and transparent colored layers of red, green, and blue as shown in FIG. The red pixel 12, green pixel 13, and blue pixel 14 are formed on a transparent substrate (glass substrate) 11, a transparent electrode layer (ITO layer) 16 is formed thereon, and a spacer 17 is further provided. It has become. Defect inspection machines for inspecting defects (scratches, foreign matter, protrusions, white defects, etc.) generated in the manufacturing process of the color filter substrate 10 having such a configuration are mainly used in the following methods.

  For example, in Patent Document 1, the following proposal is made. As shown in FIG. 6, white light or laser light is used as the light source 2, and light from the light source 2 is irradiated on each pixel pattern composed of red, green, and blue transparent colored layers on the color filter substrate 10. Next, light reflected, transmitted or scattered from the pixel pattern is received by the camera 1 using a charge coupled device (CCD), and an electric signal converted from the light is processed to detect a defect.

  In such a defect inspection apparatus, in the conventional automatic defect inspection, the determination is made only by the planar defect size, and the height management is separately performed by the review measurement based on the area size. However, the actual color filter substrate has various sizes and sizes, and the presence or absence of defects in the height method varies and is not uniform. Regardless of this situation, the actual inspection assumes every situation, and since the height is measured separately by the review machine for the inspection of all color filter substrates, there are problems such as inefficiency is there.

Japanese Patent Laid-Open No. 10-222101

  It is an object of the present invention to provide a three-dimensional defect inspection apparatus capable of performing extremely efficient defect inspection by performing not only plane area size determination but also height direction defect determination at the same time with an automatic defect inspection apparatus. To do.

The present invention is for solving the above-mentioned problems, and the invention according to claim 1 of the present invention is a three-dimensional defect inspection apparatus for simultaneously detecting defects in the planar direction and the height direction of a color filter substrate,
Conveying means for placing the color filter substrate and conveying it on the XY plane;
An imaging unit capable of synchronizing and axially moving a camera and a light source on the color filter substrate;
Image processing means for performing arithmetic processing on imaging data obtained by the imaging means;
A three-dimensional defect inspection apparatus comprising: means for performing pass / fail judgment of the color filter substrate based on the three-dimensional defect data obtained by the image processing means.

The invention according to claim 2 of the present invention is the three-dimensional defect inspection apparatus according to claim 1, wherein the camera is an area sensor camera or a line sensor camera.

  The invention according to claim 3 of the present invention is the three-dimensional defect inspection apparatus according to claim 1 or 2, wherein a plurality of the cameras are provided.

  The invention according to claim 4 of the present invention uses the three-dimensional defect inspection apparatus according to any one of claims 1 to 3 to determine a target region for defect inspection of the color filter substrate from two different camera positions. This is a three-dimensional defect inspection method characterized in that three-dimensional defect data in the height direction is calculated from image data obtained by imaging.

By automating the inspection using the three-dimensional defect inspection apparatus of the present invention, not only the planar area size determination but also the defect determination in the height direction can be performed simultaneously, and the inspection processing speed of the color filter substrate is improved. In addition, failure trend analysis is automated and speeded up so that early analysis of the cause of failure enables quick feedback to the manufacturing process.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic (top view, side view) of one Example of the inspection apparatus of this invention. Fig. 3 is a flow diagram for determining and detecting a three-dimensional defect according to the present invention. The schematic of the information acquisition method of the height direction of the present invention. The schematic diagram of the information calculation of the height direction by the stereo vision of this invention. 1 is a schematic cross-sectional view of an example showing the structure of a color filter substrate. The side schematic diagram of one example of the conventional inspection device.

  The form of determination of the defect inspection method of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic view of an embodiment of the inspection apparatus of the present invention. Fig.1 (a) is a top view, FIG.1 (b) shows a side view. FIG. 2 shows a three-dimensional defect detection determination flow of the present invention. FIG. 3 shows a schematic diagram of the information acquisition method in the height direction of the present invention. FIG. 3A shows the images A ′ and B ′ of the X axis, the Y axis, and the Z axis when the camera is located at two different points A and B with respect to P to be inspected. It is the figure shown in three dimensions. FIG. 3B is a diagram showing two dimensions of the X axis and the Z axis. FIG. 4 is a schematic diagram for calculating information in the height direction by stereo vision according to the present invention. FIG. 5 is a schematic sectional view of an embodiment showing the structure of the color filter substrate. FIG. 6 shows a schematic side view of an embodiment of a conventional inspection apparatus.

  In general, the structure of a conventional color filter substrate (CF substrate) 10 includes a red pixel 12, a green pixel 13, a blue pixel 14, and a black matrix (BM) 15 formed on a glass substrate 11, as shown in FIG. A transparent electrode layer (ITO layer) 16 is laminated thereon, and a spacer 17 is further provided.

As shown in the side view of FIG. 1B, the three-dimensional defect inspection apparatus 20 according to the present invention includes a light source 2 that can be moved in a synchronous and axial manner, with a CF substrate 10 placed on a transfer stage 3, and an upper part thereof. This is a device for detecting a three-dimensional defect in the inspection target area of the CF substrate 10 by the camera 1. As shown in the plan view of FIG. 1 (a), the above-mentioned light source 2 and the camera 1 that can move axially and synchronously have a pixel row 30 (first row R ₁ ) and a pixel column 40 (first row L _1). ), The pixel (L ₁ , R ₁ ) is sequentially moved from the pixel (L ₁ , R ₁ ) to the pixel (L _n , R ₁ ) in the T direction, and the inspection target region of the pixel row R ₁ is inspected. When the inspection is finished, the pixel is moved in the S direction and the pixel row R ₂ is inspected in the same manner as the inspection of the row R ₁ . By repeating this operation, the entire surface of the CF substrate 10 is inspected. The light source 2 and the camera 1 are not limited to one, but it is more preferable that a plurality of the light source 2 and the camera 1 are provided in order to further reduce the inspection processing time. In order to further reduce the inspection processing time, the camera 1 is preferably an area sensor camera or a line sensor camera.

  A more detailed description of the inspection method of the present invention will be given by the three-dimensional defect detection determination flow of the invention shown in FIG.

In the three-dimensional defect inspection method of the present invention, the inspection target area P of the CF substrate 10 is imaged from two different positions (position A and position B in FIG. 3) with one same camera 1 or different cameras 1. It is characterized by using stereo vision. In this case, for example, an image obtained from imaging data at position A (first position) is mainly used as a basic image, and a periodic pattern comparison with R ₂ is performed on the basis of imaging data of a row of pixels R _1. If both are different, it is determined as a defect, and defects in a certain region are collectively determined as a defect of area size.

  On the other hand, for a defect in the height direction, an image obtained from imaging data at position B (second position) is used as a reference image for a pixel determined as a defect in the defect determination of the area size described above. Then, the parallax is obtained from the imaging data at the position B, height information is calculated to obtain a height defect, and finally, the defect of the area size and the defect of the height are combined to finish the detection of the defect.

A method of calculating the height information by obtaining the parallax from the imaging data at the positions A and B will be described below. From the schematic diagram of FIG. 4, since ΔPA′B ′ and ΔPAB are similar, the following equation (1) holds.
d: (d−Xa + Xb) = Zp: (Zp−f) Formula (1)
Therefore, the Z coordinate value Zp, which is the height information at the point P, is obtained from the following equation (2).
Zp = df / (Xa−Xb) Formula (2)
In Expressions (1) and (2), d is the inter-camera distance (interval between position A and position B), f is the focal length of the camera, Xa is the X coordinate value of position A, and Xb is position B. X coordinate value, Zp represents the Z coordinate value of the position P.

As described above, the present invention is characterized in that the same position of the inspection target region is imaged from two different camera positions (position A and position B). By combining the basic image obtained from one position (position A) and the reference image obtained from the other position (position B) by this method, not only the area size defect but also the height method defect can be obtained. It can be detected at the same time. That is, using the basic image at the position A, the defect is determined by comparing the periodic pattern with R ₂ on the basis of the imaging data of the pixel row R ₁ , and R ₃ and R ₄ are similarly detected. , ... performs detection of defects in areas Zeiss collectively defects constant region and R _n, At the same time, as a reference image the image at the position B, seeking parallax from the imaging data of the position a and the position B The height information is calculated to detect the height defect, and the defect of the entire CF substrate can be detected three-dimensionally by one automatic defect inspection apparatus.

  In the inspection of the CF substrate, by using the three-dimensional defect inspection apparatus of the present invention, not only the planar area size determination but also the defect determination in the height direction can be performed at the same time, and the inspection processing speed of the CF substrate is improved. In addition, failure trend analysis is automated and speeded up so that early analysis of the cause of failure enables quick feedback to the manufacturing process.

1 Camera 2 Light Source 3 Transport Stage 10 CF Substrate 11 Glass Substrate 12 Red Pixel 13 Green Pixel 14 Blue Pixel 15 Black Matrix (BM)
16 ITO layer 17 Spacer 20 Defect inspection device 21 Camera optical axis at position A 22 Camera optical axis at position B 23 Parallax 30 Row of pixels (R ₁ , R ₂ ... R _n )
40 pixel columns (L ₁ , L ₂ ... L _n )
A 1 position of camera (position A)
B 2 positions of camera (position B)
A ′ Image pickup position at camera position A B ′ Image pickup position at camera position B P CF substrate inspection area S Scan direction T Camera / light source movable direction M CF substrate movement direction d Inter-camera distance (position A and position (B)
f Camera focal length

Claims (4)

A three-dimensional defect inspection apparatus for simultaneously detecting defects in a planar direction and a height direction of a color filter substrate,
Conveying means for placing the color filter substrate and conveying it on the XY plane;
An imaging unit capable of synchronizing and axially moving a camera and a light source on the color filter substrate;
Image processing means for performing arithmetic processing on imaging data obtained by the imaging means;
A three-dimensional defect inspection apparatus, comprising: means for performing pass / fail judgment of the color filter substrate based on the three-dimensional defect data obtained by the image processing means.   The three-dimensional defect inspection apparatus according to claim 1, wherein the camera is an area sensor camera or a line sensor camera.   The three-dimensional defect inspection apparatus according to claim 1, wherein a plurality of the cameras are provided.   Using the three-dimensional defect inspection apparatus according to any one of claims 1 to 3, a target region for defect inspection of the color filter substrate is imaged from two different camera positions, and height is obtained from the obtained image data. A three-dimensional defect inspection method characterized by calculating three-dimensional defect data in a direction.