JPH08136876A - Substrate inspecting device - Google Patents

Abstract

PURPOSE: To enable a highly accurate inspection by converting an image signal into image data, performing the image procession of image data and detecting the delicate change of color while detecting the uneveness of a substrate by comparing image data with threshold values. CONSTITUTION: A glass substrate 12 is placed on a sheet 11 for emphasizing color. After a positioning,when uniform rays of light are radiated from an illuminator 14, these rays of light irradiate the glass substrate 12 from an oblique upward. Since irradiating rays of light transmit through the glass 12, almost of them are absorbed by the sheet 11 for emphasizing color and then a reflected light on the surface of the glass 12 heads to a color CCD camera 15. The camera 15 performs a photographing with respect to the glass 12 to output an image signal corresponding to the light quantity of the reflected light from the glass 12. Then, an inspection part 17 sets respective threshold values to respective data which are subjected to the image procession and in the case a value of one side of either a horizontal direction or a vertical direction exceeds threshold values, the part 17 detects the value as the uneveness of an oriented film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applied to, for example, an LCD (Liquid Liquid).
The present invention relates to a substrate inspection device that inspects a liquid crystal alignment film in a crystal display for uneven color.

[0002]

2. Description of the Related Art As an inspection system for LCD,
For example, there are an LCD orientation distribution measurement system and a brightness unevenness inspection device. Of these, the LCD orientation distribution measurement system is LC
This is a system for measuring the brightness distribution in the angle direction of D, and the brightness unevenness inspection device is a system for inspecting the brightness unevenness of the LCD and the backlight.

Such an inspection system is an inspection for the final manufactured LCD and utilizes transmitted light from the LCD. FIG. 4 is a block diagram of such an inspection system. A backlight 2 is arranged below the LCD 1, and a CCD (solid-state imaging device) camera 3 is arranged above the LCD 1.

With such a configuration, the LCD 1 is displayed in, for example, only one color of green, and the backlight 2 emits light. In this state, the CCD camera 3 captures an image of the LCD 1 through which the light from the backlight 2 is transmitted and outputs an image signal corresponding to the brightness thereof.

The processing unit 4 performs image processing on the image signal output from the CCD camera 3 and detects display unevenness on the LCD 1. However, the unevenness of the alignment film is a slight change in the color of the alignment film in the LCD 1, for example, there are streaks or spots.

For this reason, in the above device, the transmitted light of the LCD 1 is detected to detect the unevenness. Therefore, the transmitted light cannot detect the subtle color change in the alignment film. However, it was difficult to accurately check the color unevenness.

[0007]

As described above, the LCD 1
Since the display unevenness is detected by detecting the transmitted light of the above, it is not possible to detect a subtle color change in the alignment film, and it is difficult to highly accurately check the unevenness. Therefore, the present invention is
It is an object of the present invention to provide a substrate inspection device capable of detecting a subtle color change and performing a highly accurate inspection.

[0008]

According to a first aspect of the present invention, there is provided a sheet for color enhancement arranged on one surface side of a light transmissive substrate, and an illuminating means for irradiating the other surface of the substrate with light. A color image pickup device which detects reflected light when light is radiated from the illuminating means to the other surface of the substrate and outputs an image signal corresponding to the amount of light; and an image signal output from the color image pickup device as image data. And an inspecting means for detecting at least unevenness of the substrate by projecting the image data and comparing the image data with a threshold value to achieve the above object.

According to the second aspect, the sheet is a filter having a color according to the type of the substrate. According to claim 3, the sheet is black. According to the fourth aspect, the sheet is arranged in surface contact with one surface of the substrate, or is separated by a predetermined distance. According to the fifth aspect, the illumination means changes the irradiation angle of light according to the type of substrate.

[0010]

According to the first aspect, the color enhancing sheet is arranged on one surface side of the substrate, and the other surface of the substrate is irradiated with light. As a result, the reflected light from the substrate includes light corresponding to the unevenness of the substrate.

In this state, the reflected light from the substrate is picked up by a color image pickup device, an image signal corresponding to the amount of light is output, the image signal is converted into image data for projection processing, and a threshold value is set. At least the unevenness of the substrate is detected by comparing with.

According to the second aspect, a filter having a color according to the kind of the substrate is arranged as the sheet. According to the third aspect, the black sheet is used and is arranged on one surface side of the substrate.

According to the fourth aspect, the sheet is arranged in surface contact with one surface of the substrate, or is separated by a predetermined distance.
According to the fifth aspect, it is possible to inspect the unevenness of various substrates by changing the irradiation angle of the light to the substrate according to the type of the substrate.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a substrate inspection device applied to a glass substrate used for an LCD.

A color-enhancing sheet 11 is placed on the XY table 10, and a glass substrate 12 used for an LCD is placed on the sheet 11. The color-enhancing sheet 11 is used for color-enhancing the glass substrate 12, and a matte color such as black, which corresponds to the type of the glass substrate 12, is used.

The color-enhancing sheet 11 is placed in contact with the lower surface of the glass substrate 12 or is placed on the glass substrate 12.
It may be arranged at a predetermined distance from the lower surface of the. The XY table 10 moves in the XY directions under the drive control of the drive control unit 13.

On the other hand, the lighting device 14 is used for the XY table 10.
It is located diagonally above. The illumination device 14 irradiates flicker-free and uniform light from obliquely above the glass substrate 12.

The illuminating device 14 has a structure in which the irradiation angle of the light irradiating the glass substrate 12 can be changed according to the kind of the glass substrate 12. Also, color CCD camera 1
5 are arranged in the light reflecting direction of the glass substrate 12.
The color CCD camera 15 outputs an image signal according to the amount of light reflected from the glass substrate 12 and sends the image signal to the image processing section 16.

The image processing unit 16 has a function of converting an image signal from the color CCD camera 15 into image data having a gray level value of 0 to 255. The inspection unit 17
512 × the image data converted by the image processing unit 16
Secured as 512 × 8 bit data, and this image data is projected in the horizontal and vertical directions,
Set each threshold for each image processed data,
It has a function of detecting a value exceeding this threshold as unevenness of the alignment film.

The inspection unit 17 has a function of transmitting and receiving position data to and from the drive control unit 13 and recognizing where on the glass substrate 12 the range currently being imaged by the color CCD camera 15 is. ing.

Next, the operation of the apparatus configured as described above will be described. Glass substrate 12 is sheet 11 for color enhancement
Placed on top. The glass substrate 12 is used as the alignment films 12a and 12b of the LCD as shown in FIG.

Here, when the entire color of the glass substrate 12 is imaged by the color CCD camera 15 at a time, the XY table 10 is used to position the glass substrate 12 as it is without moving. After this positioning, when uniform light is emitted from the illumination device 14, this light is emitted obliquely from above the glass substrate 12. At this time, the irradiation angle of the light with which the glass substrate 12 is irradiated is set according to the type of the glass substrate 12.

Most of the light applied to the glass substrate 12 is absorbed by the color enhancing sheet 11 by passing through the glass substrate 12, and the reflected light on the surface of the glass substrate 12 is reflected by the color CCD camera 15. Head to. That is, the color enhancement sheet 11 acts as a wavelength filter.

Therefore, the reflected light from the glass substrate 12 includes light corresponding to the unevenness of the glass substrate 12. The color CCD camera 15 is the glass substrate 1
The image pickup device 2 picks up an image and outputs an image signal according to the amount of light reflected from the glass substrate 12.

The image processing section 16 includes a color CCD camera 1
The image signal from No. 5 is converted into image data having a gray level value of 0 to 255. The inspection unit 17 secures the image data converted by the image processing unit 16.

Then, the inspection section 17 analyzes the image data as shown in FIG.
As shown in, projection processing is performed in the horizontal and vertical directions, and each threshold value is set for each piece of image-processed data. Either the horizontal or vertical value exceeds the threshold value. In that case, the value is detected as the unevenness Q of the alignment film.

On the other hand, when the glass substrate 12 is imaged for each area, the XY table 10 is moved by the drive control unit 13 to X.
Direction and the Y direction, and this movement causes the glass substrate 1 to move.
Positioning of each area in 2 is performed. Then, the color CCD camera 15 is provided for each of the positioned areas.
The glass substrate 12 is imaged by.

The color CCD camera 15 outputs an image signal according to the amount of reflected light from the glass substrate 12 which is imaged in the same manner as above. The image processing unit 16 is a color CCD
The image signal from the camera 15 is converted into image data of gray level values of 0 to 255.

The inspection unit 17 secures the image data converted by the image processing unit 16 as data of 512 × 512 × 8 bits. Then, the inspection unit 17 is 512 × 51.
As shown in FIG. 3, each image data of each area 2 is projected in the horizontal direction and the vertical direction, and each threshold value is set for each image-processed data. When either value exceeds the threshold value, that value is detected as the unevenness Q of the alignment film.

As described above, in the above embodiment, the black color enhancing sheet 11 is arranged on the lower surface side of the glass substrate 12, and the upper surface side of the glass substrate 12 is irradiated with light from an oblique direction. Since the reflected light from the glass substrate 12 is imaged by the color CCD camera 15 and the image data is subjected to a projection process and compared with a threshold value, the unevenness of the glass substrate 12 is detected. Light reflected from the glass substrate 12 includes light corresponding to the unevenness of the glass substrate 12, which causes a slight change in color of the alignment film, for example, unevenness of the alignment film such as streaks or spots. Can be detected with high accuracy.

Since this inspection of the alignment film unevenness is performed on the glass substrate 12 in the process of manufacturing the LCD, the yield can be improved by feeding back the inspection result of the alignment film unevenness to the product process.

Further, there is no inspection variation due to the difference in the visual sense of a person, the unevenness inspection of the alignment film can be automated, and the quantitative unevenness inspection can be performed. In addition, it is possible to cope with changes in illuminance of the lighting device 14 and changes in the external environment.

Further, by changing the irradiation angle of the light from the color enhancing sheet 11 and the illuminating device 14 to the glass substrate 12, the unevenness of the glass substrate 12 of each type can be inspected. it can.

The present invention is not limited to the above-mentioned embodiment but may be modified as follows. For example, the lighting device 14 may irradiate the glass substrate 12 with light from directly above. In this case, a half mirror or the like is arranged above the glass substrate 12, and the reflected light from the glass substrate 12 is transmitted through the half mirror to the color CCD camera 1.
It is sufficient to lead to 5. Further, in the above-mentioned one embodiment, L
Although the inspection of the glass substrate 12 used for the CD has been described, it can be applied as a color evaluation of the substrate.

[0035]

As described in detail above, according to the present invention, it is possible to provide a substrate inspection apparatus capable of detecting a subtle color change and performing a highly accurate inspection.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a substrate inspection apparatus according to the present invention.

FIG. 2 is a diagram showing a glass substrate of an LCD.

FIG. 3 is a diagram showing a projection process.

FIG. 4 is a schematic configuration diagram of a conventional device.

[Explanation of symbols]

10 ... XY table, 11 ... sheet for color enhancement, 12 ...
Glass substrate, 13 ... Drive control unit, 14 ... Lighting device, 15
... color CCD camera, 16 ... image processing section, 17 ... inspection section.

Claims (5)

[Claims] 1. A sheet for color enhancement arranged on one surface side of a light transmissive substrate, an illuminating means for irradiating the other surface of the substrate with light, and another illuminating means for illuminating the other surface of the substrate. A color image pickup device that detects reflected light when light is applied to a surface and outputs an image signal corresponding to the amount of light, and an image signal output from this color image pickup device is converted into image data. A substrate inspection apparatus comprising: an inspection unit that detects at least the unevenness of the substrate by performing projection processing and comparing with a threshold value. 2. The board inspection apparatus, wherein the sheet is a filter having a color according to the type of board. 3. The board inspection apparatus, wherein the sheet is black. 4. The substrate inspection apparatus, wherein the sheet is placed in surface contact with one surface of the substrate or is placed with a predetermined interval therebetween. 5. The substrate inspection apparatus, wherein the illuminating means changes the irradiation angle of light according to the type of substrate.