JPH07101195B2 - Color filter inspection method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect of a color filter in a liquid crystal color display panel, especially, a red
The present invention relates to a technique that is effective in detecting defects due to color mixture that a material for forming color pixels such as green and blue adheres to a portion other than a required portion of a filter substrate.

[0002]

2. Description of the Related Art In general, a color filter of this type basically has a plurality of colors having different spectral characteristics such as red, green and blue on one surface of a light-transmitting substrate such as a glass substrate. Color pixels, and in many cases, a light shielding pattern is provided at the boundary of each color pixel. The light-shielding pattern is said to be effective in increasing the sharpness of the display image on the display panel. As shown in FIG. 3, three kinds of defects are found in such a color filter. One is a defect 10 due to a foreign substance, which exists in a form in which at least a part is embedded in the red (R), green (G), and blue (B) color pixels 20 on one surface of the substrate 12. Another one is
It is a white defect 30 and is a pattern defect in which the color pixel 20 or the light shielding pattern 40 is not present where it should be. Further, one is a defect 50 due to color mixing, and for example, a part of the color pixel 20 of blue (B) is placed on the color pixel 20 of red (R), and other color pixel material is used in addition to the necessary part. It is an attached defect. Since the defect 10 due to foreign matter has a height,
A short circuit with the opposite substrate occurs, and white spots and other defects 30 and 50 of color mixture also deteriorate display quality.

Therefore, it is necessary to inspect for the presence or absence of these defects, and conventionally, a visual method is generally used. Further, it is possible to apply a mechanized method for inspecting a color filter, in which the inspection efficiency and accuracy are improved. For example, when detecting a defect 10 due to a foreign substance, the fact that the scattered light from the foreign substance is larger than that of other portions, as disclosed in JP-A-59-148809, is used to detect the scattered light. The defect 10 due to the foreign matter can be detected. Further, in the case of detecting the white spot defect 30, the mask inspection method utilizing transmitted light, which is disclosed in Japanese Patent Laid-Open No. 51-97380, can be applied.
As shown in FIG. 4, the light intensity of the transmitted light in the white defect 30 is larger than that in the color pixel 20 and the light shielding pattern 40. Therefore, the white defect 30 can be detected by providing a judgment standard at the line Th.

However, regarding the portion of the defect 50 due to the color mixture, the above method using scattered light or transmitted light causes
Defects cannot be effectively detected because each light intensity does not significantly differ from other portions. For example, it is difficult to distinguish the portion of the color pixel 20 from the portion of the defect 50 due to color mixing with scattered light, and with transmitted light, as shown in FIG.
As indicated by the chain line in the figure, the light intensity of the transmitted light at the defect 50 portion due to the color mixture is extremely low and is close to that level of the light shielding pattern 40 portion, and it is difficult to properly set the determination standard. . In this regard, the fact that each pattern of the color pixels 20 of the color filter and the light-shielding pattern 40 has regularity is used to perform image processing to distinguish the portion of the defect 50 due to color mixture from each regular pattern. It is possible to do so. However, the image processing requires a proper processing device, which causes a problem of increased cost.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique capable of effectively detecting a defect due to color mixture without performing image processing.

[0006]

According to the present invention, in addition to the transmitted light passing through a portion of the color filter substrate 10,
Color pixels 20 and light-shielding pattern 4 in the same portion of the base
The reflected light from 0 is also detected, and the defect is detected based on the detected light obtained by adding the transmitted light and the reflected light. A metal material such as chromium, aluminum, or nickel is often used as a material for forming the light shielding pattern 40, and these pattern forming materials have higher light reflectivity than the material for forming the color pixel 20. Therefore, by utilizing the high reflectivity, it is possible to clearly distinguish the defect 50 due to the color mixture from the portion of the light shielding pattern 40 without performing any image processing.
With the transmitted light alone, the defect 50 due to the color mixture is blocked by the light-shielding pattern 4.
It is difficult to distinguish from 0, but by adding the reflected light, as shown by the solid line in FIG.
The light intensity of the portion of 0 can be made larger than the determination standard Th, whereby only the defect 50 due to color mixture can be detected.

[0007]

1 shows an optical system of an inspection apparatus to which the present invention is applied. Color filter 10 to be inspected
For 0, two detection systems are prepared. One is a detection system by transmitted light using a first light source L1 behind the color filter 100, and the other is a second light source L2.
And a detection system by reflected light using the half mirror 200. As each light source, a halogen lamp or a white laser can be used. Color filter 10
The camera 300 above 0 receives the transmitted light and the reflected light from the color filter 100. As the camera 300, an ordinary camera for photoelectric conversion or a known one such as a three-plate color camera capable of color intensity correction can be used. When a normal camera is used, it is preferable to insert a color intensity correction filter 400 to correct the difference in light intensity based on color.
The size of the defect 50 to be detected is, for example, 20 to 100 μm or more, but the size of the pixel of the camera 300 is preferably ¼ or less of the minimum detection area. By using such an inspection device, it is possible to simultaneously detect transmitted light and reflected light from the same portion of the color filter 100 and effectively detect the defect 50 due to color mixing.

[0008]

According to the present invention, it is noted that the reflected light from the portion of the light-shielding pattern 40 is much larger than that from the portion of the defect 50 due to color mixing, and transmission from the same portion on the color filter 100 side is performed. Since light and reflected light are detected and the defect is detected based on the detection light obtained by adding them, the defect 50 due to color mixture can be effectively detected without performing image processing.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an inspection apparatus to which the present invention is applied.

FIG. 2 is a characteristic diagram showing a detection principle according to the present invention.

FIG. 3 is a cross-sectional view showing various defects in a color filter.

FIG. 4 is a characteristic diagram showing a principle of detecting a white defect.

[Explanation of symbols]

 12 substrate 20 color pixel 40 light shielding pattern 50 defect due to color mixing 100 color filter 300 camera L1, L2 light source

Claims (2)

[Claims] 1. A light-transmissive substrate is provided on one surface thereof with color pixels of a plurality of colors having different spectral characteristics, and a light-shielding pattern located at a boundary portion of each color pixel, the light-shielding pattern forming the color pixels. In a color filter inspection method for detecting defects in a color filter made of a material exhibiting higher light reflectivity than a material, in addition to transmitted light passing through a portion of the base, color pixels and light shielding of the same portion of the base A method for inspecting a color filter, which also detects reflected light from a pattern and detects a defect based on the detected light obtained by adding the transmitted light and the reflected light. 2. The method for inspecting a color filter according to claim 1, wherein the defect is a defect due to color mixture in which a material for forming the color pixel is attached to a portion other than a necessary portion of the substrate.