JP2003194669A - Inspection method and inspection device for liquid crystal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method and an inspection device capable of performing accurate visual inspection by preventing misunderstanding dust or the like on the outside face of a substrate as an internal defect. <P>SOLUTION: This inspection device 100 has a voltage application device 110 for supplying a liquid crystal display panel 10 with a voltage for liquid crystal driving, an imaging device 120 constituted from a CCD camera for photographing a driving region of the liquid crystal display panel 10, or the like, and a control device 130 connected to the voltage application device 110 and the imaging device 120 and constituted from an MPU or the like. At the inspection time, a voltage value Vop supplied to the liquid crystal display panel 10 is changed, and a plurality of images are picked up by the imaging device 120. The control device 130 detects an abnormal part wherein the appearance is changed corresponding to the change of the voltage value and the changing mode is different from peripheral parts, based on the plurality of images. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for a liquid crystal device, and more particularly to an inspection method and an inspection method suitable for inspecting the appearance of a drive region of a liquid crystal device in a state where a predetermined voltage is applied. Regarding the device.

[0002]

2. Description of the Related Art Generally, in the process of manufacturing a liquid crystal device, for example, a liquid crystal display panel, an appearance inspection step is provided for inspecting the appearance of a drive region while a predetermined drive voltage is applied to the liquid crystal display panel. In this visual inspection process,
The purpose is to find defects such as point defects, line defects, and display unevenness that occur in the liquid crystal display panel, and eliminate defective products.

In the above appearance inspection, it is often the case that the drive area is visually observed while the liquid crystal display panel is turned on to determine the presence or absence of the above defect. In some cases, the drive area of the liquid crystal display panel is photographed by a line sensor, a CCD camera, or the like, and the still image obtained by the photographing is subjected to appropriate image processing to detect a defect.

Further, in Japanese Unexamined Patent Publication No. 5-5709, two images are photographed by changing the voltage value applied to the liquid crystal display panel, and the variance of the density ratio of these two images is obtained to determine the surroundings. An inspection apparatus capable of detecting a defect having a change mode different from that of a normal region is disclosed.

[0005]

However, when a defect is detected from the image of the driving area in the above-described conventional visual inspection process, the inspection target cannot be three-dimensionally captured as in the case of visual inspection. There is a problem that it is difficult to accurately detect internal defects of the panel because the detection result includes noise such as picking up foreign matter such as dust adhering to the outer surface of the substrate of the liquid crystal display panel. . This is also the case with the inspection device described in the above-mentioned JP-A-5-5709. In this inspection device, when the voltage value applied to the liquid crystal is changed, the normal region is changed. Since all different parts are detected, the foreign matter attached on the outer surface of the substrate whose appearance change does not depend on the change of the voltage value is also detected.

Further, in the conventional appearance inspection process, if an inspection error occurs due to the noise or the like in the automatic inspection based on the image, a normal product is discarded as a defective product or a defective product is mixed in the product. Will be done. Also,
If defective products are mixed in with good products in automatic inspection, in order to completely exclude defective products from products, it is necessary to visually inspect all products that are good products in automatic inspection. .

Therefore, the present invention solves the above-mentioned problems, and an object of the present invention is to prevent a dust and the like on the outer surface of a substrate from being mistakenly recognized as an internal defect, so that an accurate appearance inspection can be performed. A method and an inspection apparatus are provided. Another object of the present invention is to provide an inspection method and an inspection apparatus that can reliably remove defective products from the product and reduce the time and effort of complementary inspection by visual inspection or the like.

[0008]

In order to solve the above-mentioned problems, a liquid crystal device inspection method of the present invention is a liquid crystal device inspection method for inspecting the appearance of a liquid crystal device. A plurality of images of the drive region of the liquid crystal device is captured in a state where the polarization angle of the light received from the liquid crystal device is changed, and the appearance is changed according to the voltage application state or the change of the polarization angle based on the plurality of images. It is characterized in that an abnormal portion that changes and whose change mode is different from the normal region is detected.

According to the present invention, the appearance changes from a plurality of images taken by changing the voltage application state or the polarization angle and the appearance of the change according to the change of the voltage application state or the polarization angle, and the change mode is the normal region. By detecting different abnormal parts, such as foreign matter adhered on the outer surface of the liquid crystal device,
It is possible to exclude from the inspection results peculiar parts that do not cause an internal defect of the liquid crystal device and whose appearance hardly changes due to the voltage application state or the change of the polarization angle, and it is possible to detect only the abnormal part caused by the internal defect. Since it becomes possible, the inspection accuracy can be improved.

More specifically, a specific portion having a different form from the change state of the normal region due to the voltage applied state or the change of the polarization angle is extracted, and the voltage applied state or the polarization angle of the specific portion is extracted. It is preferable to detect the abnormal site by excluding the specific site whose appearance hardly changes due to the change of.

In the present invention, it is preferable to detect the abnormal portion based on a difference value between the plurality of images.

According to the present invention, a difference value between a plurality of images is obtained, and the abnormal portion is detected based on the difference value, so that the voltage application state or the polarization state is determined by the absolute value of the difference value. It is possible to determine whether or not the appearance is changed according to the change in the angle, and the change mode is determined by the size of the difference between the difference value and the difference value value of the normal area (for example, the surrounding area). It is possible to quantitatively determine whether or not it is different from the normal region.

In the present invention, it is preferable that the abnormal portion is detected after excluding a portion having an appearance different from that of the normal region, which appears in an image photographed in the state where no voltage is applied to the liquid crystal device.

According to the present invention, a portion having an appearance different from that of the normal region, which appears in an image photographed without applying a voltage to the liquid crystal device, is excluded in advance, and whether or not there is an abnormal portion at another position. By detecting, it is possible to exclude a large foreign substance or the like attached to the outer surface of the liquid crystal device from the target of the inspection process, so that the inspection process can be performed easily and quickly.

In the present invention, it is preferable that the abnormal portion and the portion whose appearance hardly changes among the plurality of images are separately detected.

According to the present invention, by distinguishing and detecting the abnormal part and the part (the above-mentioned unique part) whose appearance hardly changes between the plurality of images, whether or not it is the unique part after the inspection. Since it is possible to confirm by visual inspection or the like, it is possible to further improve the inspection accuracy.

In the present invention, the voltage applied to the liquid crystal of the liquid crystal device may be changed as the voltage applied state.

In the present invention, the frequency of the voltage applied to the liquid crystal device may be changed as the voltage applied state.

In the present invention, the driving area is divided into a plurality of divided area portions, and inspection information indicating which divided area portion the abnormal portion or a portion whose appearance hardly changes between the plurality of images belongs to. Is preferred.

According to the present invention, the driving area of the liquid crystal device is divided into a plurality of divided area portions, and the inspection information indicating which divided area portion the abnormal portion or the peculiar portion belongs to is obtained. Even when the re-examination is performed by, the location of the abnormal site or the peculiar site can be easily and quickly known.

Next, a liquid crystal device inspection device of the present invention is a liquid crystal device inspection device for inspecting the appearance of a liquid crystal device.
On the basis of a voltage applying unit capable of changing a voltage application state to the liquid crystal device, an image capturing unit that captures an image of a drive region of the liquid crystal device, and a plurality of images captured while changing the voltage application state. A discriminating means for detecting an abnormal portion whose appearance changes due to the change of the voltage application state and whose change mode is different from the normal region.

According to the present invention, the appearance of the plurality of images taken by the image pickup means while changing the voltage application state by the voltage application means is changed by the determination means according to the change of the voltage application state, and the change is made. By detecting an abnormal part whose mode is different from the normal region, the appearance hardly changes due to a change in the voltage application state, such as a foreign substance adhering to the outer surface of the liquid crystal device, and a peculiarity not caused by an internal defect of the liquid crystal device. Since it becomes possible to exclude the part from the inspection result and detect only the abnormal part caused by the internal defect, the inspection accuracy can be improved.

In the present invention, the voltage applying means may be configured so as to be able to change the voltage value applied to the liquid crystal of the liquid crystal device.

Further, in the present invention, the voltage applying means may be configured to be able to change the frequency of the voltage applied to the liquid crystal of the liquid crystal device.

Another liquid crystal device inspection device of the present invention is a liquid crystal device inspection device for inspecting the appearance of a liquid crystal device, wherein the polarization angle of the light emitted from the liquid crystal device is changed to a specific polarization. Polarizing means capable of extracting components,
Voltage applying means for applying a voltage to the liquid crystal device,
Based on a plurality of images captured by changing the polarization angle of the liquid crystal device, an image capturing device that captures an image of the drive region of the liquid crystal device through the polarization device, and the appearance changes due to the change of the polarization angle, and It has a discriminating means for detecting an abnormal portion whose change mode is different from the normal region.

According to the present invention, the appearance of the plurality of images taken by the image pickup means while changing the polarization angle of the polarizing means is changed by the discriminating means according to the change of the polarization angle, and the change mode is normal. By detecting abnormal parts that are different from the area, inspection results can be obtained for peculiar parts that do not result from internal defects in the liquid crystal device, such as foreign matter adhering to the outer surface of the liquid crystal device, whose appearance hardly changes due to changes in the polarization angle. Therefore, it is possible to detect only the abnormal portion caused by the internal defect, and thus it is possible to improve the inspection accuracy.

In the present invention, it is preferable that the discrimination means is configured to detect the abnormal portion based on a difference value between the plurality of images.

According to the present invention, the discriminating means obtains a difference value between a plurality of images, and detects the abnormal portion based on the difference value, thereby responding to a change in the voltage application state or the polarization angle. Therefore, it is possible to quantitatively determine whether or not the appearance has changed and whether or not the change mode is different from the normal region.

In the present invention, the discrimination means detects the abnormal portion after excluding the portion having an appearance different from that of the normal region, which appears in the image photographed without applying a voltage to the liquid crystal device. It is preferable that it is configured as follows.

According to the present invention, the discrimination means appears in an image photographed without applying a voltage to the liquid crystal device,
Excludes from the inspection process the large foreign matter that has adhered to the outer surface of the liquid crystal device by excluding parts that have an appearance different from that of the normal area in advance and detecting whether there is an abnormal part at other positions. Therefore, the inspection process can be performed easily and quickly.

In the present invention, it is preferable that the discriminating means is configured to separately detect the abnormal portion and a portion whose appearance hardly changes between the plurality of images.

According to the present invention, the distinguishing means separately detects the abnormal part and the part (the above-mentioned unique part) whose appearance hardly changes between the plurality of images, so that the unique part is detected after the inspection. Since it is possible to confirm by visual inspection or the like whether or not there is any, it is possible to further improve the inspection accuracy.

In the present invention, the driving area is divided into a plurality of divided area portions, and inspection information indicating which divided area portion the abnormal portion or a portion whose appearance hardly changes between the plurality of images belongs to. It is preferable to have an inspection information calculating unit for obtaining

According to the present invention, the inspection information calculating means divides the drive area of the liquid crystal device into a plurality of divided area portions, and provides inspection information indicating which divided area portion the abnormal portion or the peculiar portion belongs to. By obtaining the value, the location of the abnormal portion or the specific portion can be easily and quickly known even when the reinspection is performed by visual inspection or the like. In this case, it is particularly desirable that the identification information of the liquid crystal device to be inspected is associated with the inspection information of the liquid crystal device.

The inspection method can be implemented by an operation program that can be executed by a computer. In the inspection device, the control means is a computer (microprocessor unit).
The operation program can be configured to realize the above inspection method.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of an inspection method and an inspection apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing a state in which the inspection method of the present embodiment is carried out and a schematic configuration of an inspection apparatus.

The liquid crystal display panel 10 to be inspected in this embodiment is formed by bonding substrates 11 and 12 made of a transparent material such as glass or plastic with a sealing material 13.
The liquid crystal 14 is sealed inside the sealing material 13.
A large number of electrodes (not shown) facing each other are formed on both sides of the liquid crystal 14, and these electrodes are conductively connected to wiring (not shown) drawn on the substrate 11.

The inspection device 100 includes a voltage application device 110 that supplies a voltage for driving a liquid crystal to the liquid crystal display panel 10, a drive region of the liquid crystal display panel 10 (a pair of electrodes or electrode portions facing each other, and a sandwiched therebetween. Image pickup device 120 configured by a CCD camera or the like for taking an image of a region in which pixels including the liquid crystal are arranged, and an MPU (microprocessor unit) connected to the voltage application device 110 and the image pickup device 120. And a control device 130 including the above.

The voltage applying device 110 is the liquid crystal display panel 1.
0 of the above wiring (or the input terminal formed at the tip)
Is connected to a wiring member 112 connected to a contact member (which can be formed of a connector, a flexible wiring board, or the like) 111 that is conductively connected to. In addition, the voltage applying device 110 receives the control device 1 via the output circuit 113.
It is connected to 30. The voltage application device 110 is configured to be able to change the voltage value Vop applied to each pixel of the liquid crystal display panel 10 and the frequency F of the applied voltage according to a command received from the control device 130.

The illumination 121 is configured to irradiate the liquid crystal display panel 10 with light. Also, the liquid crystal display panel 1
A pair of polarizing plates 122 and 123 are arranged on the front and back of 0,
The light emitted from the illumination 121 passes through the polarizing plate 122 and is applied to the liquid crystal display panel 10, and the light passing through the liquid crystal display panel 10 passes through the polarizing plate 123 and is guided to the imaging device 120. There is. The image pickup device 120 is connected to the control device 130 via an input / output circuit 124. The orientations of the polarizing plates 122 and 123 are set so that their polarization transmission axes are set in appropriate directions so that they are almost the same as the characteristics of the polarizing plates arranged on the front and back sides of the liquid crystal display panel 10 in a commercialized state. It is installed with the standard posture as the standard position. Here, the polarizing plate 123 is rotatably arranged in a plane including its plate surface. Imaging device 12
0 captures the drive region of the liquid crystal display panel 10 in response to a command from the control device 130, and displays the image as the control device 130.
It is designed to be sent to.

In this inspection apparatus 100, the liquid crystal display panel 10 is constructed so as to be photographed by a transmissive optical structure, but a polarizing plate is arranged between the liquid crystal display panel 10 and the image pickup device 120. , Liquid crystal display panel 10
Illumination is applied to the image pickup device 120 side,
The liquid crystal display panel 10 is irradiated with light through this polarizing plate,
It is also possible to take an image with a reflection type optical configuration in which the reflected light from the liquid crystal display panel 10 is guided again to the image pickup device 120 through the polarizing plate.

2A and 2B are detectable in this embodiment,
1 schematically shows a state of a part having an appearance different from the surroundings. Here, the substrate 11 and the substrate 12 are the same as above.
Are bonded to each other via a sealing material 13, and a liquid crystal 14 is arranged inside thereof. The electrode 11 is formed on the inner surface of the substrate 11.
a is formed, and the electrode 11a is covered with the alignment film 11b. Similarly, the electrode 12a is formed on the inner surface of the substrate 12.
Is formed, and the electrode 12a is covered with the alignment film 12b.

FIG. 2A shows a situation in which a foreign substance 15 such as dust is mixed in the liquid crystal display panel. The foreign material 15 is
It mixes in the liquid crystal 14, and its existence constitutes a defect in appearance, and also intervenes between the electrode 11a and the electrode 12a to affect the potential drop between the electrodes.
The alignment state of the liquid crystal 14 is also changed. Furthermore, the applied voltage is lowered by generating a leakage current between the electrodes 11a and 12a, and in an extreme case, the electrodes 11a and 12a are short-circuited. Such a situation generally causes point defects.

FIG. 2B shows the alignment film 11b or 12b.
Shows a situation in which the liquid crystal 14 is locally defective in orientation. In the illustrated example, an abnormal surface portion 16 is formed on the alignment film 12 b, and the abnormal surface portion 16 causes the liquid crystal 14 to be formed.
Causes alignment failure. The abnormal surface portion 16 is caused by an abnormality in the rubbing process (alignment process), unevenness of the alignment film, adhesion of impurities to the alignment film surface, or the like. In this case, the alignment failure of the liquid crystal 14 causes an abnormality in the electro-optical action in the area (such as an abnormality in the voltage-transmittance characteristic of the liquid crystal 14).

FIG. 2C shows a situation in which foreign substances (dust and the like) 17 and 18 are attached to the outer surface of the substrate 11 or 12. Since the liquid crystal display panel can be grasped three-dimensionally by visual inspection, it is relatively easy to recognize that it is a foreign substance that has adhered to the outer surface of the substrate, but the image taken by the imaging device shows the outer surface of the substrate. It is extremely difficult to determine whether it is the upper foreign matter 17, 18 or a foreign matter or other internal defect inside the panel structure. As the foreign matters 17 and 18 on the outer surface of the substrate, like the foreign matter 15, metal powder, resin powder, other dust, and the like can be considered.
In particular, cleaning marks and the like on the substrates 11 and 12 can easily occur in a normal manufacturing process.

FIG. 3 shows the appearance of the foreign material 15, the abnormal surface portion 16 and the foreign materials 17, 18 on the image. In addition, in this figure, in order to explain the appearance of a portion having an appearance different from the surroundings, such as an abnormal portion caused by a foreign substance or the like, many portions are shown in a manner different from the actual state. FIG. 3A shows a voltage value V applied to the liquid crystal.
op = 0v, the voltage value Vop = 3v in FIG.
(C) is the voltage value Vop = 5v. Liquid crystal display panel 1
In a region having a normal panel structure within the drive region of 0 (hereinafter, simply referred to as “normal region”), the liquid crystal 14 changes its alignment state with the change of the voltage value, and its appearance gradually changes. Foreign matter 17, which is attached to the outer surface of the substrate,
Since the appearance of the portion where 18 exists is not related to the change in the internal state of the liquid crystal display panel, it hardly depends on the change in the voltage value Vop.

Further, the foreign matter 1 inside the liquid crystal display panel 10
In the part where 5 exists and the part where the abnormal surface part 16 is formed, the appearance changes as the voltage value Vop changes, but the appearance change mode is different from the above normal region. Becomes For example, at the site where the foreign matter 15 exists, the appearance changes due to the presence of the foreign matter 15 itself, and the presence of the foreign matter 15 causes the change in the electric field applied state to be different from the surrounding normal area, and the abnormal surface portion 16 is formed. This is because the initial alignment state of the liquid crystal 14 is different from that of the surrounding normal region in the region where the voltage is applied and the change of the alignment state when a voltage is applied is also different from that of the normal region.

Here, the above-mentioned foreign matter 15 and abnormal surface portion 1
6. A part that exhibits a change mode different from the normal region when the voltage value is changed, such as a part where the foreign matters 17 and 18 exist, will be simply referred to as a “specific part” hereinafter.

When an inspection is performed using a plurality of images (a), (b) and (c) to which different voltage values Vop are applied as shown in FIG. It is possible to specify the positions of the foreign matters 17 and 18 on the outer surface of the substrate by extracting a portion from which the appearance change is small. In addition, the positions of the foreign matter 15 and the abnormal surface portion 16 inside the panel structure can be specified by extracting, from the above-mentioned specific parts, a part having an appearance change different from the appearance change of the surrounding normal region. it can. In general, a specific portion having a change mode different from that of the normal region is extracted, and a portion (hereinafter, simply referred to as “specific portion”) having a small change in appearance even if the voltage value changes is excluded from this specific portion ( By excluding), it is possible to detect only an abnormal part in the panel structure (hereinafter, simply referred to as “abnormal part”).

As a method of excluding or extracting a peculiar portion whose appearance change is small even if the voltage value changes, a specific threshold value is set for the appearance change amount, and the peculiar portion below the threshold value is set. A direct method is to specify a site that exhibits a change in appearance. Further, an image of the drive area of the liquid crystal display panel 10 when the voltage value Vop is set to 0 (non-lighting state) is taken, and the data of the image is used as a background image, which is different from the surrounding normal area. It is also possible to exclude a site having an appearance from the above-mentioned specific site assuming that it is the above-mentioned specific site, or to extract a specific site at the same position as the above site as a unique site with little change in appearance. it can.

FIG. 4 is a graph showing an example of the relationship between the position on the image and the brightness of a plurality of images taken with the voltage value Vop changed as described above. FIG. 4A shows a portion that does not clearly appear in the background image (voltage value Vop = 0v), but it appears as a black dot as the voltage value is changed,
The figure shows an abnormal portion (arrow in the figure) whose contrast changes with a change in voltage value. In addition, FIG.
Shows a specific portion (arrow shown in the figure) which is always shown as a black dot without depending much on the change of the voltage value Vop, and this specific portion is a foreign substance attached on the outer surface of the substrate of the liquid crystal display panel. Further, FIG. 4C shows an abnormal portion (arrow shown in the figure) that appears as a white dot that causes a contrast change different from the surroundings with a change in the voltage value Vop.

The above-mentioned abnormal portion changes depending on the change in the voltage value Vop, and the change mode is different from the surrounding normal region. As a situation where this abnormal portion occurs, as shown in FIG. 5A, when the rising characteristic (steepness) of the voltage value-transmittance characteristic in the liquid crystal display panel 10 is different from the normal region (illustrated solid line) (illustrated) One-dot chain line and dotted line). In addition, as shown in FIG.
A case where the threshold value of the voltage value-transmittance characteristic (threshold voltage value in the on-off characteristic) in the liquid crystal display panel 10 is different from the normal region (solid line in the figure) (one-dot chain line or dotted line in the figure) is also included.

FIG. 6 is a schematic diagram showing the procedure of the inspection method when the inspection is performed using the inspection apparatus 100 shown in FIG. 1 or the procedure of the operation program executed by the controller 130 of the inspection apparatus 100. It is a flowchart. First, a state in which no power is supplied from the voltage applying device 110 to the liquid crystal display panel 10 (that is, the voltage value Vop
= 0 v), the driving area of the liquid crystal display panel 10 is photographed by using the image pickup device 120, and is acquired and stored as the background image described above. At this time, from this background image, a site having an appearance different from that of the normal region, for example, a site visually recognized as a white dot or a black dot is extracted based on a predetermined threshold value assuming that it is the above-mentioned unique site, and recorded / recorded. You may save. Here, in the present embodiment, a case where the image is a monochrome image and the image data is lightness data will be described below. However, when the image is a color image, a threshold is also set for the hue and The specific site can be extracted by both the brightness. It should be noted that the processing relating to this background image is not necessarily required to be performed, and the shooting and image processing of this background image may be omitted.

Next, the voltage value Vop output from the voltage applying device 110 is set appropriately. Here, the setting of the voltage value Vop in the voltage application device 110 is performed as follows, for example. That is, from a low voltage value to a high voltage value, or vice versa, from a high voltage value to a low voltage value,
N voltage values Vop (1), V whose values monotonously change
Op (2), Vop (3), ... Vop (N) are set in advance. At this time, the numbers in parentheses indicate the identification numbers n (Vop) = 1 to N of N preset voltage values. The voltage value is set by the above N voltage values Vo.
It is performed by sequentially selecting one of p by adding it one by one from n = 1 to N.

First, of the predetermined N voltage values Vop, the voltage value Vop (1) having the identification number n (Vop) = 1.
Is set, and this voltage value is supplied from the voltage application device 110 to the liquid crystal display panel 10, and in this state, the imaging device 120
The driving area of the liquid crystal display panel 10 is photographed by. Then, the image input signal from the imaging device 120 is transmitted to the control device 130.
When it is sent to, the image is stored in the memory or the like as it is at the first shooting (when n = 1). Then, the voltage value Vop (n is a natural number larger than 1) is set again as it is, and the set voltage value is supplied from the voltage applying device 110 to the liquid crystal display panel 10, and the image pickup device 1 is operated in the same manner as described above.
Take a picture at 20. After the second and subsequent shootings are performed in this way, the image (n = j) obtained by this is
The image (n = j-1) previously captured by the control device 130 and stored in the memory and subtraction calculation (image difference calculation)
Then, the image difference data is generated. Where j is 2
It is a natural number of N.

Next, white spot inspection processing is carried out. In this white spot inspection process, from the image (n = j), a portion having a higher brightness than the surroundings (hereinafter, simply referred to as “white spot”. In this case, the portion is not only a spot-shaped portion but also a linear portion Or a part having a certain spread) is extracted, and at the position of this white point, the image difference data (brightness data) is the reference difference data (for example, the average value or the median value of the image difference data). It is determined whether or not it is a specific part having a value more than a predetermined threshold value than the above) and the image difference data is an abnormal part having a value of a predetermined minimum value or more.

That is, when the image difference data at the position of the white spot is larger than the reference difference data by the threshold value or more or smaller than the threshold value by the threshold value or more, there is a change mode different from the normal region with respect to the change of the voltage value. Determined to be a specific part. Further, when the difference between the image difference data and the reference difference data is less than the threshold value, it is not known whether it is a normal region or a specific region, so it is determined that it is not the specific region for the time being. Then, regarding the white spot determined to be the specific portion, when the image difference data at the position of the white spot is less than the above minimum value, the white spot is not based on a defect in the panel structure. For example, it is determined that the noise is caused by the foreign matter attached to the outer surface of the substrate.
Similarly, when the image difference data at the position of the white point is equal to or more than the above-mentioned minimum value when it is determined to be the specific part,
It is determined that the abnormal portion has a significant change mode according to the change of the voltage value.

If an abnormal portion is found at the above-mentioned stage, an output device (display device, printing device, sounding device, etc.) not shown, which is appropriately provided in the inspection device 100, may output an error message, The liquid crystal display panel 10 itself is similarly displayed, and the inspection is ended.

Next, if no abnormal portion is found in the white spot inspection process, the black spot inspection process is subsequently executed. This black spot inspection processing is performed by the image (n
= J), a portion having a lower brightness than the surroundings (hereinafter, simply referred to as a “black dot”. In this case, not only a spot-shaped portion but also a linear portion or a portion having a certain extent of spread. The image difference data is a specific portion having a value that is more than a predetermined threshold value from the reference difference data (for example, the average value or the median value of the image difference data) at the position of this black point. Moreover, it is determined whether the image difference data is an abnormal part having a value equal to or higher than a predetermined minimum value.

That is, when the image difference data at the position of the black dot is larger than the reference difference data by the threshold value or more or smaller than the threshold value by the threshold value or more, the change mode different from the normal region is specified with respect to the change of the voltage value. Determined as a part. Further, when the difference between the image difference data and the reference difference data is less than the threshold value, it is not known whether it is a normal region or a specific region, so it is determined that it is not the specific region for the time being. Then, regarding the black spot determined to be the specific portion, when the image difference data at the position of the black spot is less than the above-mentioned minimum value, the black spot is not based on a defect in the panel structure, and is, for example, the substrate. It is determined that it is due to foreign matter (noise) attached to the outer surface.
Similarly, when the image difference data at the position of the black spot is equal to or more than the above-mentioned minimum value when it is determined to be the specific part,
It is determined that the abnormal portion has a significant change mode according to the change of the voltage value.

If an abnormal portion is found at the above-mentioned stage, an output device (display device, printing device, sounding device, etc.) not shown, which is appropriately provided in the inspection device 100, may output a message indicating that it is defective, The same display is provided on the liquid crystal display panel 10 itself (that is, a defective product is displayed),
Finish the inspection. Here, instead of displaying the defective product, the liquid crystal display panel may simply be carried out to a place where the defective product should be placed.

If no abnormal portion is found in the white spot inspection process and the black spot inspection process, the image (n = j) is stored in the memory unless j = N. Then, n = 1 to N are added one by one, and the above series of processing is repeated until n = N. If no abnormal part is finally found in this repeated processing,
If necessary, the above output device is caused to output that the product is non-defective, or the liquid crystal display panel is carried out to the place where the non-defective product should be placed, and the inspection is completed.

FIG. 7 is an explanatory view (a) to (c) showing an example of an inspection method when an inspection is performed using the inspection device 100.
Is. It should be noted that, in this figure, a large number of specific parts and abnormal parts are shown for the sake of explanation. In this example, a plurality of drive regions 10D of the liquid crystal display panel 10 (M ×
K) divided area parts 10d [m, k] (m = 1 to M, k
= 1 to K), and the specific region or abnormal region discovered in the inspection apparatus 100 is divided into the divided region portion 10d.
Whether it exists in [m, k] is calculated from the positions of the specific part and the abnormal part detected as described above, and this is stored as inspection information. This processing is executed in the control device 130. For example, in the case of inspecting a plurality of liquid crystal display panels 10, the identification information (identification number or the like) of the liquid crystal display panels and the inspection information are stored in association with each other.
The inspection information can be easily used for each liquid crystal display panel when a specific portion or an abnormal portion is confirmed by a re-inspection such as a visual inspection in a later step.

For example, taking a case where a visual inspection is performed at the time of re-inspection as an example, [m,
By recognizing k] as the position coordinate, it is possible to know the approximate position in the drive region 10D, and thus it is possible to easily and quickly find the site to be visually inspected. Further, based on this inspection information, a member that limits the visible range so that only the range of the divided area 10d [m, k] can be visually recognized, or the divided area 10d [m, k] is enlarged and displayed. By using a means (microscope, monitor, etc.) or the like, it is possible to perform the reinspection quickly and reliably.

In this way, in the case where the number of defective products is relatively small, in the above white spot inspection process and black spot inspection process, the above threshold value may be reduced or the above minimum value may be lowered, resulting in failure. By increasing the number of liquid crystal display panels that are determined to be non-defective and re-inspecting the liquid crystal display panels that are determined to be defective, by visual inspection,
A good product can be taken out from the liquid crystal display panel determined to be a defective product. In this case, it is possible to reduce the probability that a defective product is mixed in the liquid crystal display panel that is determined to be a good product, and at the same time, it is possible to suppress the number of liquid crystal display panels that need to be re-inspected by visual inspection or the like. In this case, provide a gray zone for the above threshold and minimum value,
You may make it re-examine only the site | part which belongs to this gray zone. In this way, the number of reexamination targets can be further reduced.

In FIG. 7, the black dots shown in the figure are those determined by the inspection device 100 to be the specific parts and not the abnormal parts (that is, the peculiar parts), and the white dots shown are the abnormal parts. It is determined by the inspection apparatus 100 that there is a black dot or a white dot surrounded by a dotted line, and a black dot or a white dot surrounded by a solid line is re-determined by the re-inspection as not a specific part or an abnormal part. Was redetermined to be a specific site or an abnormal site by reexamination. Therefore, FIG. 7 (a) is finally judged as a non-defective product because neither a peculiar part nor an abnormal part was found by the re-examination, and FIG. 7 (b) is finally judged again as a peculiar part and not an abnormal part. However, FIG. 7C shows a defective product because the abnormal region was finally found by re-determination.

Here, although it is determined that the inspection apparatus 100 is a peculiar portion and not an abnormal portion, it is re-determined as an abnormal portion in the reinspection, and conversely, it is an abnormal portion in the inspection apparatus 100. Although determined, there may be some that are re-determined as a unique site but not an abnormal site in the retest.

In the embodiments described above, the case where a plurality of images are acquired by changing the voltage value as the voltage application state to the liquid crystal display panel has been described. But,
According to the present invention, also in the case where a plurality of images are acquired by changing the frequency F of the applied voltage as the voltage applied state,
The inspection can be performed by the same method and apparatus as in the above embodiment. In this case, the voltage application device 110 needs to be configured so that the frequency F of the applied voltage can be changed and supplied to the liquid crystal display panel. Here, the waveform of the applied voltage may be a drive waveform used during multiplex drive or a drive waveform used during simple drive. When the frequency of the applied voltage is changed, the appearance in the drive region changes due to the degree of change in the electric field that is applied to the liquid crystal molecules to the change in the external electric field and the magnitude of the response speed in the alignment direction of the liquid crystal molecules. Although the internal factors and appearance changes themselves are different from the above embodiment,
Similar to the above-described embodiment, in the abnormal portion caused by the internal defect of the liquid crystal display panel, the appearance change mode due to the change in the frequency F is different from the normal area change mode. In this case, the peculiar portion on the outer surface of the substrate of the liquid crystal display panel caused by foreign matter or the like is exactly the same as the case of the above embodiment, and the situation does not change at all.

Further, instead of changing the voltage value Vop or the frequency F of the applied voltage as described above, a method of changing the polarization angle of the light taken into the image pickup device 120 is also the same method and device as in the above embodiment. An inspection can be done. In this case, the voltage applying device 120 may simply supply power to the liquid crystal display panel at a predetermined voltage value and frequency. The imaging of the drive area of the liquid crystal display panel by the imaging device 120 is performed plural times by changing the polarization angle of the polarization component contributing to the imaging by a method of rotating the polarizing plate 123 within a plane including the plate surface thereof. When the polarization angle at the time of shooting is changed, the appearance changes with different retardations (= Δn
D, where Δn is a refractive index anisotropy of liquid crystal molecules and d is a portion having a substantial thickness of the liquid crystal layer), so that they are different from each other, so that a foreign substance 15 exists in the panel structure. When the abnormal surface portion 16 is formed on the alignment film, the internal factor and the change mode itself are different from those in the above embodiment, but the polarization angle is different in the abnormal portion due to the internal defect of the liquid crystal display panel as in the above embodiment. The appearance change mode due to the change is different from the normal area change mode. In this case as well, the unique portion on the outer surface of the substrate of the liquid crystal display panel caused by a foreign substance or the like is exactly the same as in the case of the above embodiment, and the situation does not change at all.

The liquid crystal device inspecting method and the inspecting device of the present invention are not limited to the above-mentioned illustrated examples, and various modifications can be made without departing from the scope of the present invention. is there.

[0071]

As described above, according to the present invention,
By preventing the dust and the like on the outer surface of the substrate from being mistaken for internal defects, an accurate visual inspection can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a liquid crystal device inspection method and an inspection device according to the present invention.

2A to 2C are enlarged cross-sectional views (a) to (c) showing structures of different types of specific parts of the liquid crystal display panel.

3A to 3C are image explanatory diagrams (a) to (c) schematically showing changes in appearance of different specific parts.

FIG. 4 is image data graphs (a) to (c) showing changes in image data of different specific parts.

FIG. 5 is graphs (a) and (b) showing changes in voltage-transmittance characteristics of a liquid crystal display panel.

FIG. 6 is a schematic flow chart showing the procedure of the inspection method of the present embodiment or the procedure of the operation program of the inspection apparatus.

FIG. 7 is explanatory diagrams (a) to (c) for explaining the inspection method of the present embodiment.

[Explanation of symbols]

10 ... Liquid crystal display panel 10D: Driving area 10d [m, k] ... Division area part 15, 17, 18 ... Foreign matter 16: Abnormal surface 100 ... Inspection device 110 ... Voltage applying device 120 ... Imaging device 122, 123 ... Polarizing plate 130 ... Control device

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2G051 AA90 AB02 CA04 CB02 CC20                       EA08                 2G086 EE10                 2H088 FA11 FA12 FA13 FA30 HA01                       HA02 HA03 HA06 HA18 KA03                       KA06 KA07 KA30 MA11 MA20                 5B057 AA01 BA02 DA03 DB02 DB05                       DB09 DC05 DC08 DC22 DC32

Claims (15)

[Claims] 1. A method of inspecting a liquid crystal device for inspecting the appearance of the liquid crystal device, comprising: a driving area of the liquid crystal device in a state in which a voltage is applied to the liquid crystal device or a polarization angle of light received from the liquid crystal device is changed. Taking a plurality of images, based on the plurality of images, the appearance changes according to the voltage application state or the change of the polarization angle, and the change mode is to detect an abnormal site different from the normal region. Characteristic liquid crystal device inspection method. 2. The inspection method for a liquid crystal device according to claim 1, wherein the abnormal portion is detected based on a difference value between the plurality of images. 3. The abnormal portion is detected after excluding a portion having an appearance different from that of the normal region, which appears in an image photographed in a state in which a voltage is not applied to the liquid crystal device. The method for inspecting a liquid crystal device according to claim 1 or 2. 4. The liquid crystal according to claim 1, wherein the abnormal part and the part whose appearance hardly changes between the plurality of images are separately detected. Equipment inspection method. 5. The method for inspecting a liquid crystal device according to claim 1, wherein a voltage value applied to the liquid crystal of the liquid crystal device is changed as the voltage application state. . 6. The method for inspecting a liquid crystal device according to claim 1, wherein the frequency of the voltage applied to the liquid crystal device is changed as the voltage application state. 7. The inspection information indicating which of the divided area portions the drive area is divided into a plurality of divided area portions, and the abnormal portion or a portion whose appearance hardly changes between the plurality of images belongs to. Claim 1 characterized by the above.
7. The method for inspecting a liquid crystal device according to claim 6. 8. A liquid crystal device inspection device for inspecting the appearance of a liquid crystal device, comprising: a voltage applying unit capable of changing a voltage application state to the liquid crystal device; and an image of a drive region of the liquid crystal device. Based on the image pickup means and the plurality of images taken by changing the voltage application state, an abnormal part whose appearance changes due to the change of the voltage application state and whose change mode is different from the normal region is detected. An inspection apparatus for a liquid crystal device, comprising: a determination unit. 9. The inspection apparatus for a liquid crystal device according to claim 8, wherein the voltage applying unit is configured to change a voltage value applied to the liquid crystal of the liquid crystal device. . 10. The liquid crystal device inspection apparatus according to claim 8, wherein the voltage applying unit is configured to change the frequency of the voltage applied to the liquid crystal of the liquid crystal device. . 11. A liquid crystal device inspection device for inspecting the appearance of a liquid crystal device, comprising: a polarizing means capable of extracting a specific polarization component by changing the polarization angle of light emitted from the liquid crystal device; Based on a voltage applying unit that applies a voltage to the liquid crystal device, an image capturing unit that captures an image of a drive region of the liquid crystal device via the polarization unit, and a plurality of images captured by changing the polarization angle. An apparatus for inspecting a liquid crystal device, comprising: a discriminating unit that changes an appearance due to a change in the polarization angle and that detects an abnormal portion whose change mode is different from a normal region. 12. The determination unit is configured to detect the abnormal portion based on a difference value between the plurality of images, according to any one of claims 8 to 11. The inspection device for a liquid crystal device according to item 1. 13. The discriminating means detects the abnormal portion after excluding a portion having an appearance different from that of the normal region, which appears in an image taken in a state in which a voltage is not applied to the liquid crystal device. The liquid crystal device inspection device according to any one of claims 8 to 12, wherein the inspection device is configured. 14. The method according to claim 8, wherein the determination means is configured to distinguish and detect the abnormal portion and a portion whose appearance hardly changes between the plurality of images. Item 14. The liquid crystal device inspection device according to any one of items 13. 15. The drive area is divided into a plurality of divided area portions, and inspection information indicating which of the divided area portions the abnormal portion or a portion whose appearance hardly changes among the plurality of images belongs to is obtained. The inspection device for a liquid crystal device according to any one of claims 8 to 14, further comprising inspection information calculation means.