JPH07286938A - Method for inspecting flat display device and optical imaging device used therefor - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an inspection method capable of increasing the reliability of inspection of a flat panel display device. [Structure] Before inspecting the LCD, a slide base 58 is provided so that light from a light source 59 does not reach the CCD camera 56.
A light-shielding plate 60 is placed so as to cover the light-transmitting hole, and the CCD camera 56 captures an image in this state. At this time, the detection level of the normal light receiving pixel of the CCD camera 56 becomes the black level, but the detection level of the defective light receiving pixel shows the white level. By detecting the image pickup result from the CCD camera 56 by the image processing board 52, the detection level of each light receiving pixel is checked to identify the defective light receiving pixel. Then, when the LCD is inspected, the imaging result of the defective light receiving pixel is corrected by using the imaging result of the normal light receiving pixels located around the defective light receiving pixel, so that the inspection reliability of the LCD is improved by the defective light receiving pixel. Avoid being damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a flat panel display device and an optical image pickup device used therefor.

[0002]

2. Description of the Related Art Flat-panel display devices such as liquid crystal display devices (LCD) have been attracting attention as small-sized and lightweight display devices that can replace cathode ray tubes. For example, the LCD can be classified into several types according to its driving method. An active matrix method is known as one of LCD driving methods. FIG. 11 shows an equivalent circuit for each pixel of this drive type LCD. As shown in the figure, in the active matrix LCD, the drive transistor 6 and the capacitor element 8 are integrated for each pixel at the intersection of the matrix of the scanning lines 2 and the data lines 4, and the contrast and We are trying to improve the display performance such as response. On the equivalent circuit diagram, the liquid crystal layer is indicated by reference numeral 10. Liquid crystal layer 1
One pixel electrode of 0 is formed in a matrix on the driving substrate together with the driving transistor 6 and the capacitive element 8, and the other counter electrode of the liquid crystal layer 10 is opposed to the driving substrate with the liquid crystal layer interposed therebetween. It is mounted on the counter substrate to be arranged.

However, in such an active matrix type LCD, it is necessary to integrate several hundred thousand driving transistors such as thin film transistors (TFTs) on a driving substrate, and this driving transistor and other wirings, etc. The problem is how to make the above-mentioned defect-free on the drive substrate, and how to improve the reliability of the inspection of the manufactured LCD.

As an inspection method to be performed after injecting liquid crystal between the driving substrate and the counter substrate, as in Japanese Patent Laid-Open No. 63-123093, the LCD is actually driven and its display screen is displayed by a CCD camera or the like. There is a method of inspecting a pixel defect by inspecting with an optical imaging device. When inspecting a pixel defect, an AC component potential A as shown in FIG. 12 is applied to the liquid crystal layer 10 through the data line 4 and the drive transistor 6 in order to drive the LCD under actual drive conditions. A common potential Vcom is applied from the counter electrode of the liquid crystal layer 10, and the common potential Vcom is the center potential (V) of the upper potential Vmax and the lower potential Vmin of the potential A.
Since it is max / 2 + Vmin / 2), an AC voltage is applied to the liquid crystal layer 10. The AC voltage is applied in order to prevent deterioration of the liquid crystal of the liquid crystal layer 10.

LCD in normal white mode, for example
In this case, the scanning line 2 shown in FIG. 11 is scanned, the drive transistor 6 is opened, and the potential A shown in FIG.
The voltage of the potential Vcom is applied, and the pixel becomes a black dot. If the drive transistor 6 or the like has a defect, the pixel becomes a white spot. Therefore, the defect can be detected by detecting the white spot with an optical image pickup device such as a CCD camera.

By the way, a CCD is formed by arranging a plurality of light receiving pixels in a matrix. However, some defects may occur in some light receiving pixels at the time of manufacture and use thereof. Regarding the defect of the light receiving pixel which occurs at the time of manufacturing the CCD, there is no problem because the correction is made at the time of shipment of the CCD camera.

[0007]

However, when the CCD camera is used, no correction is made for the defects that have occurred in some of the light receiving pixels that make up the CCD. As a result, C having a defect in such a light receiving pixel
When the LCD is inspected using a CD camera, normal LC
D may be erroneously determined to be defective, or defective LCD may be erroneously determined to be normal, resulting in a problem in the reliability of the inspection result. The above-mentioned problems similarly occur when inspecting a flat panel display device such as a plasma display panel or a light emitting diode display panel in addition to the LCD.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for inspecting a flat panel display device and an optical image pickup device used therefor, which can enhance the reliability of the inspection of the flat panel display device. .

[0009]

In order to solve the above-mentioned problems of the prior art and to achieve the above-mentioned object, a method for inspecting a flat panel display device according to a first aspect of the present invention is a method for emitting light from a light emitting means. Image pickup is performed with the image pickup means in a state where light is shielded, and based on the image pickup result, a light receiving pixel having a detection level equal to or higher than a reference level is specified as a defective light receiving pixel, and the image pickup is performed when the flat display device is inspected. Among the image pickup results of the flat panel display device by the device, the image pickup result of the specified defective light receiving pixel is corrected based on the image pickup result of the normal light receiving pixel arranged around the defective light receiving pixel, and the correction is performed. Defective display pixels included in the flat panel display device are detected based on the imaging result.

According to a second aspect of the present invention, the method for inspecting a flat panel display device is such that an image is picked up by the image pickup means while the light from the light emitting means is directly incident on the image pickup means, and based on the image pickup result. A defective light-receiving pixel whose detection level is equal to or lower than a reference level is specified as a defective light-receiving pixel, and when the flat display device is inspected, among the image pickup results of the flat display device by the image pickup device, the specified defective light receiving pixel The image pickup result is corrected based on the image pickup result of the normal light receiving pixels arranged around the defective light receiving pixel, and the defective display pixel included in the flat panel display device is detected based on the corrected image pickup result.

Preferably, the correction is performed by replacing the image pickup result of the defective light receiving pixel with an averaged value of at least a plurality of image pickup results of the normal light receiving pixels located around the defective light receiving pixel. .

An optical image pickup device according to a first aspect of the present invention is an image pickup device in which a plurality of light receiving pixels are arranged in a matrix, and a defective light receiving pixel of the image pickup device is incident on the image pickup device. A light-blocking means for blocking the light to be captured, and an image pickup result of the image pickup means shielded by the light-blocking means,
Based on the imaging result, a specifying unit for specifying a light receiving pixel whose detection level is equal to or higher than a reference level as a defective light receiving pixel
The storage means for storing the address of the defective light receiving pixel specified by the specifying means, and the image pickup result of the defective light receiving pixel corresponding to the address stored in the storage means among the image pickup results of the image pickup means And a correction unit that corrects by replacing with a value calculated based on the imaging result of the normal light-receiving pixels located around the.

According to a second aspect of the present invention, there is provided an optical image pickup device, wherein an image pickup means having a plurality of light receiving pixels arranged in a matrix and an image pickup means for detecting a defective light receiving pixel of the image pickup means. Is input, and the image pickup result of the image pickup means when the light from the light emitting means is directly emitted, and based on the image pickup result, a light receiving pixel whose detection level is equal to or lower than a reference level is set as a defective light receiving pixel. Specifying means for specifying, storage means for storing the address of the defective light-receiving pixel specified by the specifying means, and imaging result of the defective light-receiving pixel corresponding to the address stored in the storage means among the imaging results of the imaging means Is replaced with a value calculated based on the image pickup result of the normal light-receiving pixels located around the defective light-receiving pixel, and the correction means is provided.

The correction means preferably performs the correction by replacing the image pickup result of the defective light receiving pixel with an averaged value of the image pickup results of the normal light receiving pixels located around the defective light receiving pixel.

[0015]

In the method for inspecting a liquid crystal display device according to the first aspect of the present invention, before the inspection of the liquid crystal display device, the image pickup means takes an image with the light from the light emitting means blocked, and the image pickup result is obtained. From this, it is detected whether or not there is a defective light receiving pixel, and if there is a defective light receiving pixel, it is specified. In the detection of the defective light receiving pixel, if the light receiving pixel of the image pickup means is normal, if the image pickup is performed in a state where the light from the light emitting means is shielded, the detection level of the normal light receiving pixel is close to the black level. The detection level of the light receiving pixel is close to the white level. Utilizing this fact, a predetermined reference level is provided to detect a defective light receiving pixel.

That is, a light-receiving pixel whose detection level is a white level which is the detection level when light is detected despite blocking the light from the light-emitting means can be regarded as a defective light-receiving pixel. The defective light-receiving pixel identified in this way is a correction target when correcting the image pickup result of the image pickup unit. That is, if it is specified that the image pickup unit has a defective light receiving pixel, then, when the flat panel display device is imaged by the image pickup unit, the image pickup result of the specified defective light receiving pixel in the image pickup result is, It is corrected based on the imaging result of the light receiving pixels arranged around the defective light receiving pixel. Then, based on the corrected imaging result, the defective display pixel included in the flat panel display device that is the imaging target is detected.

In the method for inspecting a flat panel display device according to the second aspect of the present invention, the flat panel display according to the first aspect of the present invention described above in a state where the light from the light emitting means is directly applied to the image pickup means. Similar to the device inspection method, defective light receiving pixels are identified. At this time, since the image pickup means is irradiated with light, if the light receiving pixel is normal, the detection level of the light receiving pixel is close to the white level, but the detection level of the defective light receiving pixel is close to the black level. Utilizing this and
A predetermined reference level is provided to detect defective light receiving pixels.

The optical image pickup device of the present invention has a structure suitable for use when performing the above-described inspection method for a flat panel display device. In the optical image pickup device of the present invention, in addition to the image pickup of the flat panel display device, the substrate or machine may be picked up when, for example, inspecting a substrate that has undergone soldering or inspecting a mechanical defect. Also in this case, the reliability of the inspection using the imaging result of the optical imaging device can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display inspecting method and an optical image pickup device according to an embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram for explaining an inspection device for carrying out an inspection method for a liquid crystal display device according to this embodiment, and FIG. 2 is a block diagram of the inspection device shown in FIG.
Block diagram when identifying defective light-receiving pixels of CD, FIG.
FIG. 3 is a block diagram when inspecting a defective liquid crystal pixel of an LCD in the inspection device shown in FIG. 1.

As shown in FIG. 1, the inspection apparatus of this embodiment comprises an optical image pickup apparatus 50, an LCD control section 55, and a lens 5.
7, a slide table 58 and a light source 59. The optical image pickup device 50 includes an image processing board 52 and an A / D converter 5.
3, a control board 54, a CCD camera 56, and a light shielding plate 60.

The CCD camera 56 has a plurality of light-receiving pixels arranged in a matrix, accumulates electric charges in each light-receiving pixel in accordance with an external state within the image pickup range, and outputs the horizontal scanning signal from the horizontal scanning circuit. The charge accumulation state of the light receiving pixels located at the matrix intersections sequentially specified by the vertical scanning circuit and the vertical scanning signal is output to the control board 54 as an imaging result. The CCD camera 56 is arranged so that the LCD (liquid crystal display device) 1 mounted on the slide base 58 is included in the imaging range. Control board 54
Is the analog image signal S obtained by the CCD camera 56.
It outputs to the A / D converter 53 as 54.

The A / D converter 53 has an analog image signal S corresponding to the image pickup result input from the control board 54.
54 is A / D converted, and the digital image signal S53 corresponding to the A / D conversion is output to the image processing board 52. The image processing board 52 performs a predetermined process for inspecting and identifying a defective light receiving pixel in the CCD camera 56 based on the digital image signal S53. Image processing board 52
The processing in will be described later. The light blocking plate 60 is manufactured using a light blocking member, and has a shape that covers the light transmitting hole 58 a when it is mounted on the slide base 58.

When inspecting the LCD (hereinafter, also referred to as LCD inspection mode), the LCD control section 55 is connected to the LCD 1 to be inspected as shown in FIG. 3, and supplies a predetermined drive voltage to the LCD 1. , The liquid crystal pixels of the LCD 1 are set in the light transmitting state and the light shielding state. The slide base 58 has a light transmitting hole 58a near the center of the imaging range of the CCD camera 56,
When inspecting and identifying the defective light receiving pixel of the CCD camera 56 (hereinafter, also referred to as CCD inspection mode), the light shielding plate 60 is placed as shown in FIG. 2, and in the LCD inspection mode, the LCD 1 is displayed as shown in FIG. Placed. Slide table 58
Is, for example, horizontally slid from the position indicated by the solid line to the position indicated by the two-dot chain line in FIG. It is placed on the slide table 58.

The LCD 1 and the light shielding plate 60 are automatically slid by, for example, a transfer device, placed on the slide base 58, and carried out from the slide base 58. In addition, the light source 59 is a transparent hole 58 a of the slide base 58.
Is arranged so as to emit light toward the CCD camera 56 via the control signal S52 from the image processing board 52.
Turn on / off according to b. The light source 59 has, for example, a shutter that blocks the emitted light.

First, the LCD 1 to be inspected in the inspection method of this embodiment will be described with reference to FIGS. FIG. 9 is a diagram showing a schematic configuration of the LCD 1, and FIG. 10 is an LC.
It is an equivalent circuit diagram which shows an example of D1. As shown in FIG. 9, the LCD 1 used in this embodiment includes a transparent drive substrate 20.
And a counter substrate 22 which is also transparent.
The liquid crystal layer 10 is formed by sealing the liquid crystal between 0 and 22.
Are formed and constitute the liquid crystal cell 15. On the surface of each substrate 20, 22 located outside the liquid crystal cell 15,
Polarizing plates 26 and 28 are attached. The liquid crystal forming the liquid crystal layer 10 is not particularly limited, but for example, TN type or STN type liquid crystal is used. Polarizing plates 26, 28
The polarization axes of are orthogonal to each other.

A color filter layer 30 and a counter electrode 32 are formed on the liquid crystal layer side of one counter substrate 20.
Further, the scanning line 2 is formed on the liquid crystal side surface of the other drive substrate 22.
, The data line 4, and the drive transistor 6 and the capacitive element 8 (see FIG.
(See) and are integrated and built in a matrix. The illustration of the capacitive element 8 is omitted in FIG. 9.
The drive transistor 6 is composed of a TFT composed of, for example, an amorphous silicon film or a polysilicon film. The capacitive element 8 has a function of storing signal charge during one field time.

The pixel electrode 36 and the counter electrode 32 are
For example, it is composed of a transparent electrode such as an ITO film. Since the liquid crystal layer 10 exists between the pixel electrode 36 and the counter electrode 32, the liquid crystal layers 10 ... 10 controlled for each liquid crystal pixel are formed in the equivalent circuit shown in FIG. Liquid crystal layer 10
The common voltage Vcom is applied to the counter electrode 32 on one side. A voltage selected by the drive transistor 6 from the data line 4 is applied to the pixel electrode 36 on the other side of the liquid crystal layer 10.

As shown in FIG. 10, a vertical scanning circuit 38 is connected to the scanning line 2. The vertical scanning circuit 38 may be formed integrally with the drive substrate 22 shown in FIG. 2, but may be formed on a different substrate from the drive substrate 22. Also,
The data line 4 is connected to the video signal input terminal line 42 via the hold switch 40. The hold switch 40 is composed of, for example, CMOS, and is controlled by the horizontal scanning circuit 44. Like the vertical scanning circuit 38, the horizontal scanning circuit 44 may be formed integrally with the driving substrate 22, but may be formed on a substrate different from the driving substrate 22.

The LCD 1 includes a normal white mode LCD in which the screen is displayed in white in the normal state and a normal black mode LCD in which the screen is displayed in black in the normal state. In this embodiment, a normal white mode LCD is used as the LCD 1, and the LCD shown in FIG.
The control unit 55 sends a drive voltage to the LCD 1 so that the entire screen of the LCD 1 is displayed in black. At that time, the LCD control unit 55 sends a control signal so that the voltage applied to the liquid crystal layer of the LCD 1 changes by alternating current. In a normal LCD, the voltage of the common electrode (common potential V _com ) is set to about 6 V, so that the voltage change is made in the range of 4.0 to 8.0 V, for example.

The inspection method and the inspection of the LCD 1 by the optical image pickup apparatus of this embodiment will be described below. Figure 4
5 is a flow chart for explaining the procedure of the inspection of the LCD 1 in the present embodiment, and FIG. 5 is a flow chart for explaining the procedure in the process (step S1) for inspecting and specifying the defective light receiving pixel of the CCD camera 56 shown in FIG. It is a flowchart.

First, in step S0, for example, 40
In order to perform inspection and identification of defective light-receiving pixels (step S1) once for each lot of LCD1 of 0 to 500, the LCD1 to be inspected is the first LCD1 of one lot. Determine if there is. If so, the process of step S1 is executed. If not, the process of step S1 is skipped and the process of step S2 is executed. The process of step S1 will be described in detail with reference to FIG. As shown in FIG. 5, the process of step S1 includes the processes of steps S11 to S16.

Step S11: As shown in FIG. 2, a light shielding plate 60 is placed on the slide table 58 so as to cover the light transmitting hole 58a, and the light from the light source 59 is shielded by the light shielding plate 60, and the CCD camera 56 is exposed. Not reach

Step S12: Image pickup by the CCD camera 56 is started. At this time, the transparent hole 5 of the slide base 58
Since 8a is covered with the light shielding plate 60, the CCD camera 56 captures an image in the entire image capturing range (the light shielding plate 60) in which the incident light is shielded.

Step S13: An analog image signal S54 corresponding to the image pickup result from the CCD camera 56 is output from the control board 54 to the A / D converter 53, and the A / D
A / D conversion is performed in the converter 53. The A / D-converted digital image signal S53 is output to the image processing board 52, and in the image processing board 52, as shown in FIG.
Based on the digital image signal S53 as shown in (C), processing relating to inspection and identification of defective light receiving pixels is performed.

The waveform of the digital image signal S53 shown in FIGS. 6B and 6C is the image signal of the horizontal scanning line 56a1 of the image pickup screen 56a of the CCD camera 56 shown in FIG. 6A. The vertical axis is the detection level. Further, the horizontal axis of the waveform of the digital image signal S53 shown in FIGS. 6B and 6C indicates time, and the time on the horizontal axis is considered as the address of the light receiving pixel of the CCD camera 56 by considering the scanning pattern. be able to.

At this time, since the incident light is blocked in the entire image pickup range of the CCD camera 56, if all the light receiving pixels are normal, the detection levels of all the light receiving pixels indicated by the digital image signal S53 are as shown in FIG. As shown in 6 (B), the level approaches black (hereinafter, also referred to as black level). However, when some of the light receiving pixels have a defect, as shown in FIG. 6C, the detection level is the reference level A in the portion of the waveform of the digital image signal S53 corresponding to the defective light receiving pixel. A waveform S53a that exceeds the level and approaches a level corresponding to white (hereinafter, also referred to as a white level) appears.

Therefore, in the image processing board 52,
In the waveform of the digital layer signal S53, the waveform S53 in which the detection level exceeds the reference level A and approaches the white level S53
It is inspected whether or not a exists, and if it exists, the light receiving pixel of the address corresponding to the timing when the waveform S53a occurs is specified as the defective light receiving pixel among the light receiving pixels of the CCD camera 56. In this way, the reference level A is provided to avoid erroneously determining a normal light-receiving pixel as a defective light-receiving pixel when noise is superimposed on the waveform S53. At this time, for example, FIG.
When the light receiving pixel corresponding to the waveform S53a shown in FIG. 7 is the light receiving pixel e among the light receiving pixels a to i arranged in a matrix as shown in FIG. 7, the light receiving pixel e is specified as a defective pixel. .

Step S14: When the defective light-receiving pixel is identified in step S13, the address of the identified defective light-receiving pixel is stored in, for example, the memory built in the image processing board 52. At this time, for example, when the light receiving pixel e shown in FIG. 7 is specified as a defective pixel, the address of the light receiving pixel e is stored.

Step S15: The light shielding plate 60 is retracted from the slide base 58. The evacuation operation of the light shielding plate 60 is automatically performed by, for example, a conveying device that conveys the light shielding plate 60 provided.

As described above, step S1 shown in FIG.
Then, among the light receiving pixels of the CCD camera 56 used when the LCD 1 is inspected, the presence or absence of a defective light receiving pixel is inspected, and if there is a defective light receiving pixel, the address of the light receiving pixel is stored. The stored address of the light receiving pixel is used when correcting the image pickup result of the CCD camera 56 in step S4 of FIG. 4 described later.

In the inspection of the LCD 1 in this embodiment, after the step S1 is completed, the steps S2 to S2 shown in FIG.
The process of step S5 is performed. The processing of steps S2 to S5 shown in FIG. 4 will be described below. Step S2: From the image processing board 52 to the LCD control unit 5
5, the control signal S52a is output, and accordingly, LC
The D control unit 55 sends a driving voltage to the LCD 1 so that the entire screen is displayed in black. The LCD 1 brings all the liquid crystal pixels into a light-shielded state by the drive voltage from the LCD control unit 55.
Further, the control signal S50 is output from the image processing system 50 to the light source 59, and light from the light source 59 is applied to the LCD 1 through the light transmitting hole 58a of the slide base 58 based on the control signal S50.

At this time, if all the liquid crystal pixels of the LCD 1 are normal, that is, if there is no defective liquid crystal pixel,
The light from the light source 59 irradiated onto the LCD 1 through the light transmitting hole 58a is blocked by the liquid crystal pixels of the LCD 1 and does not reach the CCD camera 56 via the lens 57. As a result, if the LCD 1 has no defective liquid crystal pixel, the CCD
The entire image area of the camera 56 is shielded from incident light and becomes almost black. On the other hand, if the LCD 1 has a defective liquid crystal pixel, the defective liquid crystal pixel remains in the light-transmitting state without being shielded by the drive voltage from the LCD control unit 55, and the light from the light source 59 is emitted. Transmits the defective liquid crystal pixel and forms an image on the corresponding light receiving pixel of the CCD camera 56 through the lens 57. As a result, CCD camera 5
The range corresponding to the defective liquid crystal pixel in the image pickup range of 6 is close to white.

Step S3: The image processing board 52 judges whether or not the address of the defective light receiving pixel existing in the CCD camera 56 is stored in Step S1, and if it is judged that the address is stored, the step S3 is executed. The process of S4 is executed, while the process of step S5 is executed when it is determined that it is not stored.

Step S4: The image processing board 52 is A
Digital image signal S53 input from the / D converter 53
Is corrected. The correction of the digital image signal S53 in the image processing board 52 is performed by, for example, the defective light receiving pixel shown in FIG.
In the case of the light receiving pixel e shown in FIG. 5, the light receiving pixel e is specified from the address stored in step S15 shown in FIG. 5, and the light receiving pixels b, d arranged around the light receiving pixel e,
The imaging result of the light receiving pixel e is replaced with the imaging result derived from the imaging result (detection level) of h and f. In addition, in the present embodiment, one light receiving pixel corresponds to one liquid crystal pixel for the sake of simplification of description.
Several light receiving pixels correspond to one liquid crystal pixel.
The imaging result of the defective light-receiving pixel e is replaced with, for example, the value shown on the right side of the following formula (1).

(Image forming result of light receiving pixel e) = {(Image forming result of light receiving pixel b) + (Image forming result of light receiving pixel d) + (Image forming result of light receiving pixel h) + (Formation of light receiving pixel f) Image result)} / 4 (1)

At this time, for example, when the image pickup results of the light receiving pixels b and d are white level and the image pickup results of the light receiving pixels f and h are black level, the image pickup result of the light receiving pixel e is white level and black. It is replaced by the gray level which is the middle level of the levels. In this way, by replacing the image formation result of the defective light receiving pixel with a value calculated by reflecting the image formation result of the light receiving pixels around the defective light receiving pixel,
The imaging result of the defective light-receiving pixel can be made to substantially match the original imaging result. As a method of replacing the image formation result of the defective light receiving pixel with the image formation result of the surrounding light receiving pixels, in addition to the method shown in the above formula (1), for example, as shown in the following formula (2), the light receiving pixel a , B, c, f, i, h, g, d values derived from the imaging results may be used.

(Image forming result of light receiving pixel e) = {(Image forming result of light receiving pixel a) + (Image forming result of light receiving pixel b) + (Image forming result of light receiving pixel c) + (Formation of light receiving pixel f) Image result) Image forming result of light receiving pixel i) + (Image forming result of light receiving pixel h) + (Image forming result of light receiving pixel g) + (Image forming result of light receiving pixel d)} / 8 (2)

Step S5: When the process in step S4 is performed, the digital image signal S53 corrected in step S4 is used, while step S4
If the processing in step A is not performed, the A / D converter 53
Using the digital image signal S53 input from
It is inspected whether or not there is a defective liquid crystal pixel in D1. At this time, if there is no defective liquid crystal pixel on the LCD 1,
As shown in (A), the detection level of the light receiving pixel of the CCD camera 56 indicated by the digital image signal S53 becomes the black level.

On the other hand, if the LCD 1 has a defective liquid crystal pixel, as shown in FIG.
A part of the detection level 53 becomes a white level at a position corresponding to the light-receiving pixel on which the light transmitted through the defective liquid crystal pixel is imaged. Therefore, the digital image signal S
By checking the detection level of 53, it is possible to determine whether or not the LCD 1 has a defective liquid crystal pixel. In order to avoid an erroneous determination due to the superposition of noise in the determination, the reference level A is provided as shown in FIG. 6, and the digital image signal S53 has a waveform that exceeds the reference level A and approaches the white level. In this case, it is assumed that the LCD 1 has a defective liquid crystal pixel. When it is determined that the LCD 1 has a defective liquid crystal pixel, for example, the average detection level of the LCD 1 is calculated based on the number of defective liquid crystal pixels and the detection level at which the defective liquid crystal pixel is imaged, and the calculation is performed. It is determined whether the average detection level satisfies a certain standard. Then, the LCD 1 whose detection level does not meet a certain standard is treated as a defective LCD, for example.

As described above, according to the inspection method and the optical image pickup apparatus of the present embodiment, even when the light receiving pixel of the CCD camera 56 has a defect, the image formation result of the defective light receiving pixel is received by the surrounding light. By performing the correction using the image formation result of the pixel, it is possible to obtain the image signal according to the original appearance of the LCD. As a result, the LCD based on the image signal
Since the presence or absence of the defect can be accurately determined, the reliability of the inspection result can be improved. Further, in the optical image pickup apparatus of the present embodiment, even if some of the light receiving pixels have defects after shipping, it is necessary to repair or replace the apparatus by correcting the image pickup result of the defective light receiving pixels. It is also economically superior.

The inspection method and the optical image pickup apparatus of the present invention are not limited to the above-mentioned embodiments. For example, the inspection of the defect of the light receiving pixel of the CCD camera 56 (step S1 shown in FIG. 4) may be performed twice to improve the reliability of the inspection. Further, when the LCD 1 is imaged by the CCD camera 56 when the entire LCD 1 does not fall within the imaging range by one image pickup, the CCD camera 56 is imaged a plurality of times to inspect liquid crystal pixel defects in the entire LCD 1. You may

Further, in the above-mentioned embodiment, in step S1 shown in FIG. 4, the defect of the light receiving pixel when the light source 59 irradiates the CCD camera 56 with a constant amount of light is inspected. Then, for example, the defect of the light-receiving pixel may be inspected when the light amount is changed from a very small amount to an excessive amount or from an excessively small amount. Further, as a method of correcting the image pickup result of the defective light receiving pixel in step S4 of FIG.
The method is not limited to the methods of Expressions (1) and (2) as long as the method uses the value calculated using the imaging result of the light receiving pixels located around the defective light receiving pixel.

Further, in the present embodiment, the light-shielding plate mounted on the slide table 58 is exemplified as the light-shielding means for shielding the light from the light source 59, but the detection level of the image pickup range of the CCD camera 56 is substantially black. If possible, the shutter is not limited to the light-shielding plate and may be, for example, the shutter provided in the CCD camera 56 or the light source 59 itself.

Further, in the present embodiment, an example in which the shading plate 60 is slid on the slide base 58 provided between the light source 59 and the lens 57 and mounted is described. It may be provided at another position as long as it can block the light emitted from 59 to the CCD camera 56. Further, in this embodiment, 400 to 500 L
CCD camera 5 for each lot with CD1 as one lot
Although the example of detecting the defective light receiving pixel of No. 6 has been described,
The number of LCDs 1 constituting one lot is arbitrary. Also,
The defective light receiving pixel of the CCD camera 56 is detected by, for example, 1
It may be performed each time one LCD 1 is inspected.

The second embodiment will be described. In the above-described first embodiment, the case where the defective light-receiving pixel included in the CCD camera 56 and showing the detection level close to the white level even though the light is not incident is corrected has been described. In the present embodiment, a case will be described in which a defective light receiving pixel included in the CCD camera 56, which has a detection level close to a black level even though light is incident, is corrected.

In the inspection method of the flat panel display device of this embodiment and the optical device used therefor, in the CCD inspection mode, as shown in FIG.
The CCD camera 56 is irradiated via the. And the light source 5
Despite being irradiated with the light from 9, the light receiving pixel having the detection level close to the black level is identified by exceeding the predetermined reference level (for example, the reference level A shown in FIG. 8), and the identified light reception is performed. The pixel address is stored in the memory built in the image processing board 52. And CCD camera 5
When the image pickup by 6 is performed, the image pickup result of the defective light receiving pixel is corrected based on the address stored in the memory of the image processing board 52. The correction is the same as that described in the first embodiment described above.

In the above-mentioned embodiments, the LCD is exemplified as the flat display device, but in addition to the LCD, a flat display device such as a plasma display panel or a light emitting diode display panel may be an inspection object. Further, in the above-described embodiment, the CCD is exemplified as the image pickup means, but an image pickup tube, a microcathode or the like may be used instead of the CCD. Further, in the above-described embodiment, the LCD device using the optical image pickup device 50 is used.
However, the optical imaging device 50 may be used to image the substrate or the machine when inspecting the soldered substrate or inspecting the machine for defects. Also in this case, the reliability of the inspection based on the imaging by the optical imaging device 50 can be improved.

[0058]

As described above, according to the inspection method of the flat display device and the optical image pickup device of the present invention, even if the light receiving pixel has a defect, the image forming result of the defective light receiving pixel can be used as the surrounding image. By performing correction using the image formation result of the light receiving pixels, it is possible to obtain an image pickup result according to the original appearance of the flat panel display device. As a result, the presence / absence of a defect in the flat panel display device can be accurately determined based on the imaging result, and the reliability of the inspection result can be improved. Further, according to the optical image pickup apparatus of the present invention, an accurate image pickup result can be obtained even when a defect occurs in the light receiving pixel after shipping.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an inspection method for a liquid crystal display device and an optical image pickup device according to an embodiment of the present invention.

FIG. 2 is a block diagram when a defective light receiving pixel of a CCD is specified in the inspection method and the optical imaging device shown in FIG.

FIG. 3 is a block diagram when performing a defect inspection of an LCD in the inspection method and the optical image pickup apparatus shown in FIG.

FIG. 4 is a flowchart illustrating a procedure of an LCD inspection method according to an embodiment of the present invention.

5 is a flowchart for explaining the procedure in step S1 shown in FIG.

6A is an image pickup screen of a CCD camera, and FIG. 6B is C.
An image signal output from the CCD camera when the CD camera has no defective light receiving pixels, and (C) is an image signal output from the CCD camera when the CCD camera has defective light receiving pixels.

FIG. 7 is a diagram for explaining correction of an imaging result of a defective light receiving pixel existing in the CCD camera.

8A and 8B are diagrams for explaining an image signal from a CCD camera when an image of the LCD is picked up, FIG. 8A is an image signal when the LCD has no defective liquid crystal pixel, and FIG. 8B is a defective liquid crystal pixel on the LCD. It is an image signal when there is.

FIG. 9 is a diagram showing a schematic configuration of a liquid crystal display device to be inspected in an example of the present invention.

FIG. 10 is an equivalent circuit diagram showing an example of a liquid crystal display device.

FIG. 11 is a diagram showing an equivalent circuit for each pixel of an LCD driven by an active matrix system.

12 is a schematic waveform diagram of a drive signal supplied to the LCD shown in FIG.

[Explanation of symbols]

 1 ... LCD 50 ... Image processing system 52 ... Image processing board 53 ... A / D converter 51 ... Optical system 54 ... Control board 55 ... LCD control unit 56 ...・ CCD camera 57 ・ ・ ・ Lens 58 ・ ・ ・ Slide stand 58a ・ ・ ・ Transparent hole 59 ・ ・ ・ Light source 60 ・ ・ ・ Light-shielding plate

Claims (6)

[Claims] 1. A flat display is provided from a direction facing the light emitting means by an image pickup means in which a plurality of light receiving pixels are arranged in a matrix while irradiating light from the light emitting means to a display portion of the flat display device. In an inspection method for imaging a device and inspecting the display pixels of the flat display device for defects based on the imaging result, the imaging device performs imaging with light from the light emitting device blocked, and the imaging Based on the result, the light receiving pixels whose detection level is equal to or higher than the reference level are identified as defective light receiving pixels, and when the inspection of the flat panel display device is performed, the identification is performed among the image pickup results of the flat panel display device by the image pickup device. The image pickup result of the defective light receiving pixel is corrected based on the image pickup result of the normal light receiving pixel arranged around the defective light receiving pixel, and the flattening is performed based on the corrected image pickup result. A method of inspecting a flat display device for detecting defective display pixels included in a flat display device. 2. The plane display from a direction facing the light emitting means by an image pickup means in which a plurality of light receiving pixels are arranged in a matrix while irradiating light from the light emitting means to a display section of the flat panel display device. A method for inspecting an image of a device and inspecting the presence or absence of a defect in a display pixel of the flat display device based on a result of the image capturing, wherein the image is captured by the image capturing unit in a state where light from the light emitting unit is directly incident on the image capturing unit. Based on the imaging result, the light receiving pixel whose detection level is equal to or lower than the reference level is specified as a defective light receiving pixel, and when the inspection of the flat display device is performed, the image pickup result of the flat display device by the image pickup device Among them, the image pickup result of the specified defective light receiving pixel is corrected based on the image pickup result of the normal light receiving pixel arranged around the defective light receiving pixel, and the corrected image pickup result is obtained. A method for inspecting a flat display device, which detects defective display pixels included in the flat display device based on the result. 3. The correction is performed by replacing the image pickup result of the defective light receiving pixel with an averaged value of at least a plurality of image pickup results of the normal light receiving pixels located around the defective light receiving pixel. Item 3. An inspection method for a flat panel display device according to Item 1 or 2. 4. An image pickup means having a plurality of light receiving pixels arranged in a matrix, a light blocking means for blocking light incident on the image pickup means when specifying a defective light receiving pixel of the image pickup means, and light blocking by the light blocking means. The image pickup result of the image pickup means is input, and based on the image pickup result, a specifying unit that specifies a light receiving pixel whose detection level is a reference level or higher as a defective light receiving pixel, and a defective light receiving pixel specified by the specifying unit. A storage unit that stores an address, and an image pickup result of a defective light receiving pixel corresponding to an address stored in the storage unit out of an image pickup result of the image pickup unit, and an image pickup result of a normal light receiving pixel located around the defective light receiving pixel. And an amendment unit for amendment by replacing with a value calculated based on the above. 5. An image pickup means having a plurality of light receiving pixels arranged in a matrix, a light emitting means for irradiating the image pickup means with light when identifying defective light receiving pixels of the image pickup means, and light from the light emitting means. The image pickup result of the image pickup unit when directly irradiating is input, and based on the image pickup result, a specifying unit that specifies a light receiving pixel whose detection level is equal to or lower than a reference level as a defective light receiving pixel, and is specified by the specifying unit. A storage unit that stores the address of the defective light receiving pixel, and an image pickup result of the defective light receiving pixel corresponding to the address stored in the storage unit among the image pickup results of the image pickup unit An optical imaging device comprising: a correction unit that replaces and corrects a value calculated based on a pixel imaging result. 6. The correction means performs the correction by replacing the image pickup result of the defective light receiving pixel with an averaged value of the image pickup result of the normal light receiving pixels located around the defective light receiving pixel. Item 5. The optical imaging device according to item 5.