JPH0943097A - Color filter defect inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect white omission fault for each color by providing, on the optical path between a light source and a photoelectric transfer means, a color filter by which photodetection amount, with transfer means, and optical quantity at each color part of the color filter are made almost constant. SOLUTION: A color filter substrate 1 is placed on a test stage 2, and the light of a light source 3 is made incident on the substrate 1 through an optical amount adjusting filter 4. At the substrate 1, it transmits or is reflected on the filter pattern of red, green and blue, and becomes incident an a CCD cameras 5 and 5', and the signal is inspected for default by a detection circuit part. In addition, color filters 6 and 6' are provided before the light from the light source 3 is incident on the cameras 5 and 5'. By adjusting color of the filters 6 and 6', detection ability difference for each color caused by the difference in light transmission factor among filter pattern colors of the substrate 1 is adjusted. With this, white omission fault of each color or fault on a projection is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection device for a color filter used in a liquid crystal display device or the like.

[0002]

2. Description of the Related Art Conventionally, the following means have been used for defect inspection of color filters for liquid crystal display devices. That is, as shown in FIG. 1, the light emitted from the light source 3 that irradiates the color filter substrate 1 on the stage 2 is transmitted or reflected by the pattern portion of the color filter substrate 1, and photoelectric conversion means, for example, It is captured by the CCD line sensor 5 or 5'and converted into an electric signal.
This signal is processed and judged by the detection circuit section to detect a white spot defect of several tens of μmφ and a defect due to a protrusion in the pattern section. Here, the white spot defect means that a part where incident light is almost transmitted as it is due to a partial defect of the color filter part or the black matrix part.

Here, an example of a method for determining processing in the detection circuit section will be described. First, the transmitted light signal captured by the CCD line sensor 5 is as shown in FIG.
The reflected light signal captured by the CCD line sensor 5'is as shown in FIG. 2 (b) or (c). FIG.
FIG. 2B is an example of a color filter having a black matrix of a metal chrome film, and FIG. 2C is an example of a color filter having a black matrix of a colored resin film. In addition,
In FIG. 2, the horizontal axis represents the position on the color filter substrate having the repeating pixel portion of red (R), green (G), and blue (B), and the vertical axis represents the intensity of the electric signal. FIG.
The middle portion A represents the signal obtained from the blank defect portion on the color filter substrate. Here, for example, as shown in FIG. 3, one cycle of the signal of FIG. 2C, which is a set of signal patterns in each of the R, G, and B parts, remains in the obtained waveform and is in the position axis (horizontal axis) direction. Shift. Next, the signal obtained by taking the difference between the shifted signal and the original signal of FIG. 2C is as shown in FIG. 4, and only the white defect portion in the G and B pixel portions is extracted as a signal. It Alternatively, FIG. 2 (c)
There is also a method of moving the inspection portion of the line sensor to the R, G and B pixel portions adjacent to the inspection portion of (1) to obtain a signal as shown in FIG. 3 and taking the difference between the signal and the signal obtained in FIG. 2 (c). is there.
Further, the sizes of these defects can be known from the width of the position axis in the figure, and a portion where a signal having a width equal to or larger than the prescribed size of the defective portion is obtained is detected as a defective portion.

However, since there are differences in the detection sensitivities of the R, G, and B color photoelectric conversion means, a large difference occurs in the signal levels of the two defective portions shown in FIG. Moreover, in addition to the signal obtained from the true defective portion, noise is included due to various electrical factors or factors such as unevenness of the color filter surface. These have made it difficult to set the slice level, which is the reference signal level for recognizing and determining the defective portion.

That is, optical characteristics of R, G, B pigments or dyes used in color filters,
That is, the difference in the amount of light received by the photoelectric conversion means is caused by the difference in the transmittance or the reflectance, and the higher the value of the transmittance or the reflectance is, the smaller the difference from the transmittance or the reflectance of the white defect portion is. Therefore, there is a problem in the detection accuracy as a defect.

[0006]

The standard required for a color filter, that is, the maximum size of a blank defect that can be ignored in terms of performance is, for example, that the size of the defective portion is 30 to 80 μmφ.
It is either less than or equal to a certain level and there is no difference in the standard for each color, or a specific standard is specified for each color. However, conventionally, the inspection machine is not designed so as to be able to set the difference in the detection power depending on the colors so as to satisfy these standards. The present invention eliminates the difference in detection sensitivity in the inspection machine as described above, and makes all the colors of R, G, and B have the same sensitivity or the white difference of each color of R, G, and B due to the difference in sensitivity based on a specific standard. The purpose is to enable detection of missing defects.

[0007]

The present invention is directed to a light source for irradiating light onto a color filter for a liquid crystal display device, and photoelectric conversion for receiving light transmitted or reflected by a pattern portion of the color filter and converting it into an electric signal. And a defect detecting device for detecting a white spot defect and a protrusion defect of the pattern portion based on an electric signal obtained by the photoelectric conversion device, wherein a photoelectric conversion is performed from a light source. A color filter is provided in the middle of the path through which the light up to the means is provided, which makes the light quantity received by the photoelectric conversion means substantially equal in the red, green, and blue color portions of the color filter. It is a defect inspection device for a color filter.

That is, a color filter is attached between the light source and a sensor, for example, a CCD line sensor, in the middle of the path through which light passes so as to eliminate the difference in the detection power between the R, G, and B colors, or It is a defect inspection apparatus that uses a method of adjusting to a difference in detection power based on a standard. In the case of transmitted light inspection, in order to deal with R and B with low transmittance,
High transmittance due to the use of purple filter G
The amount of light of R, G, and B that finally enters the CCD line sensor is made uniform so that R, G, and R have the same sensitivity.
This is a defect inspection device that enables detection of all white and white defects. In the reflected light inspection, since the reflectance characteristic is different from the transmitted light, a color filter matching the characteristic is used, for example, a blue-green filter is used corresponding to the high reflectance of R. , R light amount is suppressed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the defect inspection apparatus of transmission type shown in FIG. 5 and reflection type shown in FIG. 6, a color filter substrate 1 to be inspected is mounted on a stage 2, and a xenon lamp and a halogen lamp are used. Light emitted from the light source 3 using a fluorescent lamp or the like reaches the color filter substrate 1 through the light amount adjustment filter 4, and red (R), green (G),
CC connected to the detection circuit by transmitting or reflecting the filter pattern of each color of blue (B)
D (charge-coupled device) is incident on the camera 5 or 5 ', the image obtained there is converted into an electric signal, and the defect inspection processing is performed in the detection circuit section as described above.

Here, in the device according to the present invention, in addition to the above-described structure, the color filter 6 is provided at an arbitrary position until the light emitted from the light source 3 enters the CCD line sensor 5 or 5 '.
Place. The color filter 6 may be made of any material and means, but for example, a glass plate coated with a coloring pigment is used. By adjusting the color of the color filter 6, it is possible to adjust the detection power which has been different for each color due to the difference in the light transmittance between the filter patterns on the color filter substrate 1 in the related art.

As shown in the graph of FIG. 7, the light transmittance curves for the R, G, and B colors of the color filter indicated by the thin lines show the difference in the transmittance of each filter. Since the transmittance of the G color filter is high, the white defect of G color has a small difference between the light transmittance of the defective portion and the light transmittance of G color, and is difficult to detect as compared with other colors. Here, as the color filter 6 used for the transmitted light incident on the CCD line sensor 5, a purple filter showing the light transmittance curve shown by the thick line in FIG. The amount of light that has passed through the color filter and then that of the color filter 6 is approximately the same. Therefore, the detectability of the blank defect of each color becomes equal. For example, as shown in Table 1 below, in the conventional method, there is a variation in the minimum size of the white spot defect that can be detected for each color. However, according to the present invention, the minimum white spot defect detection size should be the same. You can

[0012]

[Table 1]

The color filter 6'used for the reflected light incident on the CCD line sensor 5'also similarly transmits light for correcting the difference in the light amount due to the difference in the light reflectance of the R, G and B color portions. Use a filter with a rate curve.

[0014]

As described above, according to the present invention, a color filter, particularly a purple filter, eliminates the difference in detection sensitivity in an inspection machine, and all R, G, and B colors have the same sensitivity or are specified. It is possible to adjust so that a white spot defect or a protrusion defect of each color of R, G, and B can be detected by the difference in sensitivity based on the standard.

[0015]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a conventional color filter defect inspection apparatus.

2A to 2C are examples of signals of a pattern portion obtained by a photoelectric conversion unit.

FIG. 3 is an example of a signal obtained by shifting FIG. 2 (c) by one cycle in the position axis direction so that the waveforms of a set of signal patterns in R, G, and B parts match.

FIG. 4 is an example of a signal obtained by taking the difference between the signals of FIGS. 2 and 3 (c).

FIG. 5 is an explanatory diagram showing one embodiment of the present invention.

FIG. 6 is an explanatory diagram showing another embodiment of the present invention.

FIG. 7 is a graph showing an example of the light transmittance of the color filter used in the present invention together with an example of the light transmittance of each color of the color filter.

[Explanation of symbols]

 1 color filter substrate 2 stage 3 light source 4 light intensity adjustment filter 5 CCD line sensor 6 color filter

Claims (1)

[Claims] 1. A light source for irradiating light onto a color filter for a liquid crystal display device, a photoelectric conversion means for receiving light transmitted or reflected by a pattern portion of the color filter and converting it into an electric signal, and the photoelectric conversion means. In a defect inspection device for a color filter, which comprises defect detection means for detecting a blank defect and a protrusion defect of the pattern portion based on the obtained electric signal, in a path through which light from the light source to the photoelectric conversion means passes. A defect inspection for a color filter, characterized in that a color filter is provided on the way, which makes the amount of light transmitted or reflected by each of the red, green and blue pixel portions of the color filter received by the photoelectric conversion means substantially equal. apparatus.