JP3270336B2 - Image quality inspection apparatus for liquid crystal display and inspection method therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display image quality inspection apparatus and method for automatically performing an image quality inspection of a liquid crystal display.

[0002]

2. Description of the Related Art In a method of manufacturing a liquid crystal display,
Conventionally, when performing an image quality inspection, an operator performs the inspection visually while switching to various display pixels. However, in the visual inspection, the pass / fail judgment varies depending on the operator. Also, even for the same worker,
Examination accuracy often depends on physical condition. In order to solve this problem, in recent years, there has been developed an inspection device that quantitatively performs image quality inspection by performing image processing on a screen displayed on a liquid crystal display using an imaging device. In such an inspection device, inspection is often performed with the ratio of the pixels of the liquid crystal display to the imaging element of the imaging device being about 1 to 3 times in consideration of the resolution of the imaging device and the speed required for image processing.

[0003]

However, when a pixel defect inspection of a liquid crystal display is performed in a state where the ratio of the pixel of the liquid crystal display to the image pickup device of the image pickup device is about 1: 1, the size of the pixel on the surface or inside the liquid crystal display is small. If foreign matter of a size adheres, these cannot be distinguished. When it is attempted to determine a pixel defect and a foreign substance from a difference in shape, it is necessary to make a pixel of the liquid crystal display correspond to a tens of times of imaging elements. However, if the resolution of the imaging device is increased, the number of image processings increases accordingly, and there is a problem that the inspection processing time increases.

According to the present invention, even if the ratio of the pixel of the liquid crystal display to the image pickup device of the image pickup device is about one to one, processing of the imaged pixel enables the discrimination between the foreign matter adhering to the liquid crystal display and the pixel defect. An object of the present invention is to provide a high-speed image quality inspection apparatus for a liquid crystal display and an inspection method therefor.

[0005]

According to the first aspect of the present invention, a battery
A display control device for displaying a liquid crystal display having a light, an imaging device for imaging the display screen, an image processing device for processing an image signal of the imaging device to detect a position of abnormal image quality, and controlling image quality inspection. A control device that performs the control signal, the display control device controls the liquid crystal display ,
The entire display white or the backlight
And instructing switching means to output an indication of the entire non-display does not receive a control signal at the lighting state, image quality abnormality and entirely hidden and when the detection result of the image processing apparatus was entirely white display of the liquid crystal display Comparing the position data of the image quality abnormality in the case of performing, the image quality abnormality identification means for identifying foreign matter adhering to the liquid crystal display and pixel defects of the liquid crystal display,
An image quality inspection apparatus for a liquid crystal display, comprising:

According to a second aspect of the present invention, there is provided the image quality inspecting apparatus for a liquid crystal display according to the first aspect, wherein the image quality abnormality identifying means of the control device includes an image quality abnormality when the liquid crystal display is entirely white-displayed. An image quality abnormality of the liquid crystal display is identified by taking a difference between the position data of the image quality abnormality when the image is not displayed.

According to a third aspect of the present invention, an image of a display screen of a liquid crystal display having a backlight is picked up , a picked-up image signal is processed to detect a position of abnormal image quality, and the liquid crystal display is turned on by the backlight. Receives a control signal when the light is on.
Quality abnormality and the backlight in the case of the digit entire white display
This is an image quality inspection method for a liquid crystal display, characterized by comparing position data of image quality abnormality in a case where a display signal is not displayed entirely without receiving a control signal in a lighting state of a light source and discriminating a foreign matter and a pixel defect.

According to a fourth aspect of the present invention, there is provided the image quality inspection method for a liquid crystal display according to the third aspect, wherein the image quality abnormality when the liquid crystal display is entirely white and the image quality abnormality when the entire liquid crystal display is not displayed. It is characterized in that abnormalities in the image quality of the liquid crystal display are identified by taking the difference between the data.

In the present invention, an image displayed on a liquid crystal display is taken in from an image pickup device, and the position of abnormal image quality is detected. At this time, abnormal image quality due to foreign matter and abnormal image quality due to pixel defects are detected. Next, without displaying the liquid crystal display, the image is taken in from the imaging device, and the position of the abnormal image quality is detected. At this time, an image quality abnormality due to foreign matter is detected. By comparing the positions of the image quality abnormalities obtained from the two images, the image quality abnormalities present in both the display and the non-display are foreign matters, and the others are pixel defects. Therefore, if the difference between the image quality abnormality when displayed and the position data of image quality abnormality when not displayed is taken, the data of the foreign matter is deleted and only the data of the pixel defect remains. In this way, it is possible to discriminate the foreign matter and the pixel defect of the liquid crystal display.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of an image quality inspection apparatus according to the present invention. The image quality inspection apparatus includes a liquid crystal display 1, a display control device 2 for displaying the image on the liquid crystal display 1, a liquid crystal display 1
An image capturing apparatus 3 that captures a display screen above the image processing apparatus, an image processing apparatus 4 that processes an image signal from the image capturing apparatus 3 to detect a position of an abnormal image quality, and a computer 5 that controls image quality inspection Be composed.

The liquid crystal display 1 comprises a liquid crystal panel 1a and a backlight 1b. When no control signal is received from the display control device 2, the liquid crystal panel 1a transmits light from the backlight 1b. The liquid crystal panel 1a realizes various screen displays on the liquid crystal display 1 by blocking or transmitting light from the backlight 1b by receiving a control signal from the display control device 2.

An image on the liquid crystal display 1 captured by the imaging device 3 is processed by the image processing device 4 to detect an abnormal image quality of the liquid crystal display 1. The computer 5 controls the display control device 2 and processes data from the image processing device 4.

FIG. 2 is an explanatory diagram showing an example of a liquid crystal display display screen. The liquid crystal display screen 6 includes a pixel defect (hereinafter, referred to as a black spot defect) 7 that always displays black and a black foreign substance 8 existing on the surface or inside of the liquid crystal display. FIG. 2 shows these image quality abnormalities 7,
8 shows an enlarged view of FIG.

An image quality inspection for the liquid crystal display screen 6 will be described. FIG. 3 is a flowchart showing an image quality inspection process using the image quality inspection device. First,
In response to a display instruction from the computer 5, the display control device 2 turns on the backlight 1b to display the entire surface of the liquid crystal display 1 in white (step S1), and images the display screen of the liquid crystal display 1 with the imaging device 3 (step S1).
2). The image signal from the imaging device 3 is processed by the image processing device 4 to detect an abnormal image quality. However, when the liquid crystal display 1 is displayed, when the pixel ratio of the liquid crystal display 1 and the element ratio of the imaging device 3 are about 1: 1, the black spot defect 7 and the black foreign matter 8 are both regarded as dot-like dark image quality abnormalities, The distinction is hard to distinguish. Therefore, the position of the abnormal image quality is sent to the computer 5 and stored (step S3).

Next, in response to an instruction from the computer 5, the display control device 2 sets the liquid crystal display 1 to a non-display state with the backlight 1b turned on, and captures an image of the display screen of the liquid crystal display 1 by the imaging device 3 (step S5). .
Since the liquid crystal display 1 is in the non-display state, the black spot defect 7 is not displayed. On the other hand, since the light from the backlight 1b is blocked at the portion of the black foreign material 8, it can be regarded as a dot-like dark image quality abnormality. The image processing device 4 detects a foreign substance 8 having an image quality abnormality when the liquid crystal display 1 is not displayed, and stores the position in the computer 5 (step S).
6). The computer 5 reads out the inspection result in the display state and the inspection result in the non-display state from the storage unit, compares the inspection result in the non-display state, and removes the image quality abnormality due to the foreign matter by obtaining the difference, thereby obtaining the black spot defect 7 (step S7). .

According to the above-mentioned method, it is not necessary to perform enlarged imaging, and the pixel defect 7 of the liquid crystal display 1 and the foreign matter 8 attached to the liquid crystal display 1 can be distinguished at high speed.

[0017]

According to the present invention, the image quality abnormality when the liquid crystal display is displayed and the image quality abnormality when the liquid crystal display is not displayed are compared based on the detection result of the image processing apparatus, and the foreign matter and the pixel defect are identified. The failure mode of the liquid crystal display can be automatically and accurately identified at high speed without using a high-resolution imaging device.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing an example of abnormal image quality of a liquid crystal display screen.

FIG. 3 is a flowchart illustrating an image quality inspection process using the image quality inspection apparatus.

[Explanation of symbols]

 Reference Signs List 1 liquid crystal display 1a liquid crystal panel 1b backlight 2 display control device 3 imaging device 4 image processing device 5 computer

Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) G01M 11/00 G01N 21/956 G02F 1/13 101 G09F 9/00 352 G09G 3/36

Claims (4)

(57) [Claims] A display control device for displaying a liquid crystal display having a backlight; an imaging device for imaging the display screen; an image processing device for processing an image signal of the imaging device to detect a position of abnormal image quality. A control device for controlling image quality inspection, wherein the control device includes the display control device, the liquid crystal display ,
When the backlight is lit , the control signal is received.
And instructing switching means to output an indication of the digits not entirely hidden, the image processing apparatus a detection result from the quality abnormality in the case where the quality abnormality and entirely hidden in the case where the entire white display of the liquid crystal display An image quality inspection apparatus for a liquid crystal display, comprising: an image quality abnormality identification unit that compares position data and identifies a foreign matter adhering to the liquid crystal display and a pixel defect of the liquid crystal display. 2. An image quality abnormality identifying means of the control device calculates a difference between position data of an image quality abnormality when the liquid crystal display is entirely white and an image quality abnormality when the liquid crystal display is not entirely displayed, thereby obtaining an image quality abnormality of the liquid crystal display. 2. The image quality inspection apparatus for a liquid crystal display according to claim 1, wherein the image quality abnormality is identified. Wherein capturing the display screen of the liquid crystal display having a backlight, and detects the position of the image quality abnormality by processing the captured image signal, the liquid crystal display, said bar
In the lighting state of quality abnormality and the backlight in the case where the entire white display, which has received the control signal in a lighting state of the backlight
An image quality inspection method for a liquid crystal display, comprising comparing position data of an image quality abnormality in a case where the entire image is not displayed without receiving a control signal, and identifying a foreign matter and a pixel defect. 4. An image quality abnormality of the liquid crystal display is identified by taking a difference between the position data of the image quality abnormality when the liquid crystal display is entirely white and that of the image quality abnormality when the liquid crystal display is not entirely displayed. An image quality inspection method for a liquid crystal display according to claim 3.