JPH0712742A - Color filter fault detecting device - Google Patents

Abstract

PURPOSE:To pick-up image with the use of image pick-up elements having different color-sensitive characteristics for red, green and blue as if image pick-up elements having uniform color-sensitive characteristics for red, green and blue are used CONSTITUTION:Light turning knobs 17, 18, 19 are manipulated so as to adjust the light quantities of light sources 13, 14, 15, and the brightness of picked-up images of filter elements 11R, 11G, 11B are set to one and the same value. If a fault 22 is present in a part of the filter element 11B, its brightness distribution is clearly different from those of the filter elements 11R, 11G adjacent thereto, and accordingly, a signal processing device 21 can easily find out the fault, and accordingly, the necessity of a troublesome signal process carried out by the processing device 21 can be eliminated.

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 color filters used in color TVs, color liquid crystal displays and the like.

[0002]

2. Description of the Related Art Conventionally, a defect of a color filter used in a color TV, a color liquid crystal display or the like has been inspected by a defect inspection apparatus shown in FIG. 7, for example. That is, in FIG. 7, 1 is a color filter to be inspected, and this color filter 1 is arranged so that the illumination light of the fluorescent lamp 2 which is a linear light source installed on the back side has a uniform luminance distribution. It is illuminated by the fluorescent lamp 2 through the diffuser plate 3 thus formed. Color filter
The transmitted light that illuminates 1 passes through color filter 1, and the transmitted image of color filter 1
Placed opposite the surface of, for example, C of 5000 pixels
The image is picked up by the image pickup device 4 which is a line sensor of a CD (Charge Coupled Device). The image signal of the color filter 1 picked up by the image pickup device 4 is output to the signal processing device 5 including a CPU and the like, and is subjected to arithmetic processing in the signal processing device 5 so that the color filter 1 loses or overlaps colors or has dust. Defects such as adhesion are inspected.

[0003]

By the way, as shown in FIG. 8, the color filter 1 has a black stripe 1a.
It is composed of red (R), green (G), and blue (B) filter elements 1R, 1G, 1B surrounded by
It consists of 0 elements. FIG. 8 shows an example of images sequentially picked up by the image pickup device 4 when the color filter 1 or the image pickup device 4 thus configured moves in a direction orthogonal to the aa direction. , Aa
The case where the defective portion 6 exists in the blue filter element 1B of the line will be described.

The illumination light that illuminates the color filter 1 is
Light with a wavelength that depends on the emission spectrum of fluorescent lamp 2,
The image is captured by the image sensor 4 after passing through the color filter 1.However, due to the difference in the transmittance of the filter elements 1R, 1G, and 1B and the color sensitivity characteristics of the image sensor 4, the images are captured at different brightness levels. To be done. FIG. 9 shows a state of the luminance distribution along the aa line.

However, in FIG. 9, the luminance distribution missing due to the defective portion 6 is shown by a broken line, but since the luminance distributions of the filter elements 1R, 1G, 1B are also different,
A signal processing device based on the luminance distribution shown in FIG.
In order for 5 to judge the defective portion 6 as a defect, complicated signal processing such as calculation processing of the area of the luminance distribution of each color and correction processing of the red, green, and blue color sensitivities of the image sensor 4 is required. is there.

The present invention has been made in view of the above circumstances, and an image pickup device having uniform red, green, and blue color sensitivity characteristics even when image pickup is performed by image pickup devices having different red, green, and blue color sensitivity characteristics. An object of the present invention is to provide a color filter defect inspection device capable of capturing an image as an element.

[0007]

In order to achieve the above object, the present invention provides a color filter to be inspected, which includes red, green and blue filter elements, and independent red, green and blue light. Illuminating means for illuminating the color filter with light obtained by synthesizing light from the respective light sources, an image pickup device for picking up an image of the color filter illuminated by the illuminating means, and the respective light sources. The light quantity of the light emitted from the lighting device and the color of the color illuminated by the lighting means with the light amount adjusted by the light adjusting means. Signal processing means for inspecting a defect of the color filter based on an output of the image pickup device which picks up an image of the filter.

[0008]

Since the present invention is configured as described above, the dimming means adjusts the light amount of each light source of the illuminating means and sets the brightness of the captured image of each filter element imaged by the image sensor to the same brightness. Thus, if there is a defect in a part of the filter element, it is clearly different from the brightness distribution of the adjacent filter element, and the signal processing unit can easily judge it as a defect, and the troublesome signal processing by the signal processing unit is unnecessary.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a color filter defect inspection apparatus according to an embodiment of the present invention. In FIG. 1, 11 is a color filter to be inspected.
Is illuminated by a lighting plate 12 installed on the back side thereof.
The illumination plate 12 receives three illumination lights of red (R), green (G), and blue (B) emitted from three independent light sources 13, 14, and 15, respectively.
Three colors are combined and introduced by way of the branch optical fiber 16.

That is, each of the three light sources 13, 14, 15 comprises a halogen lamp and a filter for extracting light of red (R), green (G) and blue (B) wavelengths, respectively.
The light emitted from each of these light sources 13, 14 and 15 is shown in FIG.
As shown in FIG. 3, each has a spectral characteristic with no overlapping region. In addition, the three-branch optical fiber 16 includes three input optical fibers 16R, 16G, and 16B, and these input optical fibers.
The mixing optical unit 16a that uniformly combines the red (R), green (G), and blue (B) illumination light input from 16R, 16G, and 16B, and the illumination light combined by this mixing optical unit 16a Output optical fiber output to the illumination plate 12
16b and 3 input optical fibers 16R, 16
Illumination lights emitted from the three light sources 13, 14 and 15 are input to the G and 16B, respectively. Further, the amount of illumination light emitted from each of the light sources 13, 14, 15 can be adjusted in each wavelength range by adjusting the dimming dials 17, 18, 19 provided in each of the light sources 13, 14, 15. It can be set arbitrarily.

Further, the transmitted light illuminating the color filter 11 is transmitted through the color filter 11, and the transmitted image of the color filter 11 is arranged on the surface of the color filter 11, for example, a CCD line of 5000 pixels. An image is picked up by the image sensor 20 including a sensor. Image sensor
The image signal of the color filter 11 picked up by 17 is C
The signal is output to the signal processing device 21 including a PU and the like, and is subjected to arithmetic processing in the signal processing device 21 to inspect for defects such as missing or overlapping colors of the color filter 11 or adhesion of dust.

On the other hand, as shown in FIG. 3, the color filter 11 has the same structure as in FIG.
It consists of red (R), green (G), and blue (B) filter elements 11R, 11G, and 11B surrounded by 11a, and one line consists of about 500 elements. FIG. 3 shows an example of images sequentially picked up by the image pickup device 4 when the color filter 11 or the image pickup device 20 configured as described above moves in a direction orthogonal to the bb direction. The signal is input to the signal processing device 21 and processed. While observing this processing result on the monitor display (not shown), the operator can adjust the dimming dial 17,1 provided on each light source 13,14,15.
Operate 8,19 to adjust the amount of light from the light sources 13,14,15
The brightness of each filter element 11R, 11G, and 11B sensed by 20 is set to be the same brightness. Therefore, the image sensor
The image pickup sensitivity of 20 is adjusted uniformly for each color, and FIG. 3 shows a picked-up image when the image pickup sensitivity of the image pickup element 20 is adjusted uniformly.

Next, the operation of the embodiment of the present invention having the above construction will be described.

First, the image pickup device 20 picks up an image of the filter element 11R, 11G, 11B of an arbitrary line of the color filter 11.
Based on the picked-up image, the light amount of the light sources 13, 14, 15 is adjusted by the light control dials 17, 18, 19 to uniformly set the image pickup sensitivity of the image pickup device 20. After the image pickup sensitivity of the image pickup device 20 is set, the color filter 11 is inspected for defects.

That is, as shown in FIG. 3, assuming that the defective portion 22 exists in the blue filter element 11B of the bb line of the color filter 11, the dimming dials 17, 18, 19 are provided.
Since the image pickup sensitivity of the image pickup device 20 is adjusted uniformly for each color, an image signal having a luminance distribution along the line bb as shown in FIG. 4 is picked up by the image pickup device 20. In FIG. 4, the luminance distribution missing due to the defective portion 22 is shown by a broken line, but as is clear from FIG. 4, the luminance distribution of the blue filter element 11B in which the defective portion 22 exists and this blue filter are shown. Comparing the luminance distributions of the normal red and green filter elements 11R and 11G adjacent to the element 11B, the luminance is the same, but the distribution widths are clearly different, and the defective portion 22 becomes the blue filter element 11B. It becomes easy to judge that it exists.

Therefore, on the basis of the image signal output from the image pickup device 20, it is judged whether there is a defect such as missing or overlapping of colors in the color filter 11 or adhesion of dust, and the defect of the color filter 11 is inspected. In the signal processing device 21, it is possible to judge whether or not there is a defect in each filter element 11R, 11G, 11B simply by judging and comparing the distribution width of the luminance distribution of the image signal of each filter element 11R, 11G, 11B. Is performed.

In this way, the signal processing device 21 determines and compares the distribution width of the luminance distribution of the image signal to determine the presence of a defect, thereby correcting the red, green, and blue color sensitivities of the image sensor 20. This eliminates the need for cumbersome signal processing, speeds up the processing speed for defect inspection, and enables highly reliable defect inspection.

Note that the defect determination method in the above-described embodiment is simple, so that the distribution width of the luminance distribution of the image signal is determined.
Although the comparison method is used, the invention is not limited to this.

In the above embodiment, the illumination plate 12 illuminates the color filter 11 directly. However, the present invention is not limited to this, and as shown in FIG. 5, a space between the illumination plate 12 and the color filter 11 is provided. Color filter 11 with diffusing plate 23
May be indirectly illuminated, and since it is possible to illuminate with softer light and brightness unevenness is reduced, it is possible to suppress image noise during defect inspection.

In the above embodiment, in order to set the image pickup sensitivity of the image pickup device 20 uniformly for each color, the operator operates the dimming dials 17, 18, 19 to set the light intensity of the light sources 13, 14, 15 respectively. However, the present invention is not limited to this, and as shown in FIG. 6, an image input from the image sensor 20 by the signal processing device 21 with the automatic light control function added to the light sources 13, 14, 15. Light source by light intensity control signals 24, 25, 26 generated based on the signal
13,14,15 may be controlled to adjust the light quantity,
It is possible to automatically control the light sources 13, 14, and 15.

Further, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0023]

As described above in detail, according to the color filter defect inspection apparatus of the present invention, the light control means adjusts the light amount of each light source of the illumination means and each filter element of the color filter imaged by the image sensor. By setting the brightness of the captured image of 1 to the same brightness, when a defect exists in a part of the filter element, the brightness distribution of the adjacent filter element is obviously different, and therefore the signal processing unit detects the defect of the color filter. This has an excellent effect that the determination can be easily made, and further, the troublesome signal processing by the signal processing means is not necessary and the processing speed for the defect inspection can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a color filter defect inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing spectral characteristics of red, green, and blue light sources.

FIG. 3 is a diagram showing an example of a captured image by an image sensor adopting the present invention.

FIG. 4 is a diagram showing a luminance distribution along line bb in FIG.

FIG. 5 is a diagram showing a first another embodiment of the present invention.

FIG. 6 is a diagram showing a second embodiment of the present invention.

FIG. 7 is a diagram showing a conventional color filter defect inspection apparatus.

FIG. 8 is a diagram showing an example of an image captured by an image sensor in a conventional device.

9 is a diagram showing a luminance distribution along line aa in FIG.

[Explanation of symbols]

 11 ... Color filters 11R, 11G, 11B ... Red, green, and blue filter elements 12 ... Illumination plate (illumination means) 13, 14, 15 ... Red, green, and blue light sources 17, 18, 19 ... Dimming dial (Light control means) 20 ... Imaging element 21 ... Signal processing device (signal processing means)

Claims (1)

[Claims] 1. A color filter to be inspected, which comprises red, green, and blue filter elements, and three independent light sources for emitting red, green, and blue light, respectively, and combine the light from these light sources. Illuminating means for illuminating the color filter with the above-mentioned light, an image pickup element for picking up an image of the color filter illuminated by the illuminating means, and each filter element for adjusting the light quantity of each light source to be picked up by the image pickup element Of the color filter based on the output of the image pickup device that picks up the color filter illuminated by the illumination unit with the light amount adjusted by the light adjustment unit and the brightness adjustment of the captured image of the color filter. A color filter defect inspection apparatus comprising a signal processing unit for inspecting a defect.