JP2003344299A - Defect inspection device for color filter and detect inspection method for color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect inspection device capable of precisely inspecting the surface of a color filter for defect. <P>SOLUTION: This defect inspection device for color filter for performing a defect inspection by radiating light from a light source to the color filter comprises an imaging means for imaging the transmitted light and reflected light of the radiated light, and a detection means for detecting a defect only when the respective signals of the transmitted light and reflected light are detected in the same coordinate in the detection of defect by image processing the signal obtained by the imaging means. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection device for color filters and the like, and more particularly to a device for detecting micro black defects.

[0002]

2. Description of the Related Art Conventionally, a white defect on a color filter,
Defects such as black defects and granular projection foreign matter occur, and these eventually reduce the yield of the product, so inspection was performed to detect these defects.

As an inspection method, there have been a method of performing manually and a method of using an inspection device. As an automatic inspection of a color filter, it is general to detect a particulate projection foreign substance by reflected light and detect a black defect and a white defect by transmitted light. A black defect is a defect (dark defect) that looks like a black dot when a foreign substance, etc., falls on the pattern and the amount of transmitted light drops only in that part, and a white defect increases the amount of transmitted light due to missing or missing patterns. It is a defect (light defect) that looks like a white dot.

[0004]

However, since it is impossible to distinguish between the front surface and the back surface of the color filter by the transmitted light, a foreign matter that can be easily blown off on the back surface is also detected as a black defect, which results in an over-detection state and high accuracy. The inspection was not completed.

The present invention overcomes the drawbacks of the prior art,
It is an object of the present invention to provide a method for detecting a black defect of a color filter more accurately.

[0006]

In order to solve the above problems, the present invention has the following constitution. In a defect inspection apparatus for a color filter that irradiates a color filter with light from a light source to perform a defect inspection, an image capturing unit that captures transmitted light and reflected light of the emitted light, and image processing the signal obtained by the image capturing unit. A defect inspection apparatus for a color filter, comprising: a detection unit that detects a defect only when detection signals of transmitted light and reflected light are detected at the same coordinates when detecting a defect. In a defect inspection method for a color filter that irradiates a color filter with light from a light source, the transmitted light and reflected light of the emitted light are photographed by an image capturing means, and the resulting signal is image-processed to detect the defect. A defect inspection method for a color filter, wherein a defect is detected only when detection signals of transmitted light and reflected light are detected at the same coordinates.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The automatic defect inspection apparatus for a color filter of the present invention detects a defect by irradiating the color filter with transmitted light and reflected light, taking an image with an image pickup means, and image-processing the obtained signal. This is an automatic inspection device, which inspects by shining light on the color filter with the colored surface of the color filter facing upward. The light source is located about 400 mm above the substrate and passes through a condenser lens located about 200 mm above the substrate to irradiate the substrate with light uniformly. The light is applied to the entire width of the color filter, and the light with a width of about 5 mm is applied in the flow direction. The angle of the light irradiated on the substrate is set to 80 ° as shown in Fig. 1. A CCD sensor that detects reflected light is installed at a position about 250 mm above the substrate, and about 250 mm below the substrate. A CCD sensor that detects transmitted light is installed on the. A CCD sensor that detects reflected light is attached so that it can receive light that is specularly reflected, and a CCD that detects transmitted light.
The sensor is installed at the place where the irradiated light passes (on the optical axis). The field of view of the CCD sensor is set to be about 50 mm, and there are 8 for reflected light and 8 for transmitted light in the width direction.
I have a stand installed. The color filter is composed of a red, green, and blue colored layer formed on a glass substrate, and an overcoat and a transparent electrode layer on the colored layer.
The coloring layer is a composition containing acrylic resin, polyimide resin, or the like as main pigments such as red, blue, or green, and auxiliary pigments such as yellow. The overcoat is a transparent resin such as an acrylic resin, a polyimide resin, or an epoxy resin. The transparent electrode is composed of an oxide of indium and tin. A xenon lamp, a halogen lamp or the like is generally used as the light source, but the light source is not limited to this.
As shown in FIG. 1, light can be irradiated from the upper part of the color filter to the entire width direction, the color filter can be moved in the direction of the arrow in the figure to irradiate almost the entire area, and an image can be taken by an image pickup means such as a CCD camera. . The resolution of the CCD camera is preferably 5 μm to 25 μm, but considering noise etc. 8
μm to 15 μm is more preferable. If the resolution is too low, noise will be detected, and if the resolution is high, the small defect to be detected will not be detected. The substrate transfer speed is preferably such that the resolution of the camera is 8 to 15 μm. Further, as shown in FIG. 1, black light is accurately detected by imaging reflected light and transmitted light from one light source and comparing the detection signals of both.

The colored pattern black defect inspection apparatus of the present invention makes it possible to accurately detect only the defect on the color filter by combining and detecting the transmission illumination and the reflection illumination.

[0009]

Embodiment 1 Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram for carrying out the detection method of Example 1, and shows an apparatus for automatically inspecting defects by a CCD line sensor when a color filter is used as an inspection sample. 1 is a light source, a xenon lamp (xenon lamp manufactured by USHIO INC.)
UXL-151D-O), 2 and 3 are CCD line sensors (500 effective pixels)
0) image pickup camera, 4 is a color filter for Red, G
Reen and Blue are patterned and coated with 1 μm overcoat. 5 is an image processing device. Devices for imaging the sample and the imaging cameras 2, 3 etc., if all of them are stationary, the imaging cameras 2, 3
Has one or more CCD line sensors arranged in a straight line, and the image of the color filter 4 is formed on the light receiving surface of the CCD line sensor by the lens. Only the image on the straight line of the color filter is captured. However, in the first embodiment, the color filter 4 is rotated and moved in the direction orthogonal to the linear CCD line sensor so that the entire surface of the sample is imaged. The transportation speed was 5.4 m / min.
A condenser lens 7 uniformly illuminates the inspection substrate and forms a light source image at the entrance pupil position of the CCD.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an automatic inspection apparatus in an embodiment, in which a color filter is conveyed with a colored surface facing upward in a direction of an arrow, and light is emitted from a light source CC
The reflected light is imaged by D2 for image processing, and the transmitted light is imaged by CCD3 for image processing. In the figure, 1 is a light source (xenon lamp), 2 and 3 are imaging cameras (resolution 15 μm), 4
Is a color filter, 5 is an image processing apparatus, and 6 is a color filter transport roll. The imaging cameras 2 and 3 have a CCD area sensor, and the entire image of the color filter is formed on the CCD area sensor through the lens. Light source 1
Illuminates the entire surface of the color filter. Transport roll 6
The gap is narrow within the range that does not affect the inspection and is about 100 mm.
Open Also, when detecting a black defect, reflected light,
The output is set to be detected only when the transmitted light detects the same defect. The color filter of the inspection sample is a pattern in which red, blue, and green colored pattern parts are periodically arranged. For testing purposes, a plurality of black defects of a predetermined size are made in advance at predetermined positions in the colored pattern part. It has a coloring pattern. The types of black defects are those that left Cr (mirror surface) of the black matrix and those that were left undeveloped for each color. When the light is applied to the minute black defect portion of the colored portion, the reflected light and the transmitted light are respectively imaged on the CCD and image-processed by the image processing device. At this time, in the reflected light, the Cr black defect is detected as a reflective bright defect, and the black defect of each color is detected as a reflective dark defect. The transmitted light detects each black defect as a dark defect. By combining the detection results of transmitted light and reflected light, all the black defects on the color filter were accurately detected, and the adhered foreign matter on the back surface was not detected.

COMPARATIVE EXAMPLE 1 The following is an example in which the detection of transmitted light is set to output a black defect. Although all the black defects produced in the inspection sample were detected, the foreign substances attached to the back surface of the color filter, which may not be detected, were also detected.

[0012]

As described above, by combining the reflected light and the transmitted light to detect the defect, the automatic inspection apparatus of the present invention is automated for the sample having the colored periodic pattern area or the colored substantially pattern area. The present invention provides a highly accurate defect detection device.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a defect inspection apparatus of the present invention.

[Explanation of symbols]

1: Light source 2: CCD line sensor (for reflected light) 3: CCD line sensor (for transmitted light) 4: Color filter 5: Image processing device 6: Transport roll

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Claims (2)

[Claims] 1. A defect inspection apparatus for a color filter, which irradiates a color filter with light from a light source to inspect the defect, and an image pickup means for picking up transmitted light and reflected light of the emitted light, and a signal obtained by the image pickup means. A defect inspection apparatus for a color filter having a detection means for detecting a defect only when detection signals of transmitted light and reflected light are detected at the same coordinates when a defect is detected by image processing . 2. A defect inspection method for a color filter, wherein a color filter is irradiated with light from a light source for defect inspection, and transmitted light and reflected light of the irradiated light are photographed by an imaging means, and the obtained signal is subjected to image processing. A defect inspection method for a color filter, wherein the defect is detected only when the detection signals of the transmitted light and the reflected light are detected at the same coordinates when the defect is detected.