JPH07311563A - Method and device for liquid crystal display and information processing device - Google Patents

Abstract

PURPOSE:To improve the yield of liquid crystal panels by making pixel defects inconspicuous in liquid crystal panels while permitting the existence of these pixel defects. CONSTITUTION:The liquid crystal display device is provided with a pixel defect memory 1 which stores pixel defect data 1a composed of information on the coordinates regarding pixel defects and display conditions such as color and luminance in a liquid crystal panel 3 and pixel defect data 10 read from this pixel defect memory 1. It is also provided with a picture processing unit 2 which generates image data G1 subjected to compression-elongation processing so that pixel data which is selected from the group of pixel data that constitutes image data G based on the pixel data G inputted externally and whose coordinates and display conditions are close to those of pixcel defects are displayed on top of the pixel defects to give the image data G1 to the liquid crystal panel 3.

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 technology and an information processing technology, and more particularly to a technology effectively applied to a pixel defect countermeasure of a liquid crystal panel used as a display means such as a workstation or a personal computer.

[0002]

2. Description of the Related Art For example, a liquid crystal panel has been increasingly used as a display device for information processing equipment such as a workstation and a personal computer, and a liquid crystal panel of a TFT system has become the mainstream. For example, in the case of a color LCD, this TFT liquid crystal panel has one pixel made up of a total of 3 dots for each color of R, G and B, and each dot is made up of a thin film transistor (TFT) formed on the surface of the liquid crystal panel. For example, a liquid crystal panel having a configuration of 1024 × 768 pixels is composed of about 2.4 million transistors. It is difficult to completely form all of these transistors, and it is a major technical problem that some defects, that is, pixel defects, occur during manufacturing. Since a pixel defect has the maximum brightness or the minimum brightness, the appearance of the pixel defect changes depending on which of the R, G, and B dots the defect appears. Cannot be used as, and the yield decreases.

Therefore, conventionally, for example, Press Journal Co., Ltd., issued January 20, 1991, "Monthly Semiconductor World" 1991.2, P132-P.
135, "Repair Technology for LCDs", etc., physically repairs by cutting a short circuit portion of a wiring pattern in an LCD panel, which causes a pixel defect, with a laser, or a circuit. By providing a redundant circuit in part of the configuration,
Measures such as improving yield by repairing defective parts have been taken.

[0004]

However, in the case of the prior art as described above, the manufacturing process of the LCD panel is complicated by the repair process, and the circuit configuration is complicated by the redundant circuit. There's a problem. In addition, there is a problem in that it is impossible to remedy or prevent a pixel defect, a deterioration in image quality, or the like that occurs during actual use after shipment by the physical defect countermeasure during manufacturing as described above.

It is an object of the present invention to provide a liquid crystal display technique which allows the existence of pixel defects in a liquid crystal panel, makes the existence of pixel defects inconspicuous, and improves the yield of liquid crystal panels. .

Another object of the present invention is to allow the existence of pixel defects in the liquid crystal panel, thereby preventing the manufacturing process of the liquid crystal panel, the circuit structure, etc. from being unnecessarily complicated.
An object of the present invention is to provide a liquid crystal display technology capable of improving the yield of liquid crystal panels and the display image quality.

Still another object of the present invention is to provide a liquid crystal display technique capable of relieving the occurrence of pixel defects and image quality deterioration during actual use of the liquid crystal panel.

Still another object of the present invention is to provide an information processing technique capable of maintaining and improving the image quality of a display image without being affected by the presence of pixel defects in a liquid crystal panel of a liquid crystal display device. To do.

[0009]

In the liquid crystal display technology of the present invention, the coordinates of the pixel defect of the liquid crystal panel on the screen, the brightness,
A means for storing chromaticity information is provided, pixel data having coordinates, luminance, and chromaticity closest to the pixel defect is searched from the input image data, and the searched pixel data is detected on the pixel defect. Alternatively, a means for compressing / expanding or moving the image data of the peripheral portion of the pixel defect so as to be displayed in the vicinity without changing the image of the image is provided.

Further, in the information processing technique of the present invention, when a liquid crystal display device is used as the information output means, the position of a pixel defect on a liquid crystal panel in the liquid crystal display device or the position of a pixel defect in the liquid crystal display device is compared with image data given to the liquid crystal display device. Depending on the state, compression / expansion processing or display position movement processing is performed without changing the image of the image data in advance.

[0011]

In the above-described liquid crystal display technology of the present invention, the compression / expansion processing is performed, for example, when the pixel data closest to the pixel defect exists on the same horizontal plane as the pixel defect and at coordinates farther from the display start position than the pixel defect. , The pixel data closest to the pixel defect is compressed by processing the image data closer to the display start position than the pixel data closest to the pixel defect, and the image data on the opposite side of the display start position is expanded from the pixel data. Can be moved to the display start position side and displayed on or near the pixel defect. Also, the same can be done in the vertical direction. Such processing can be realized not only for pixel defects found during manufacturing, but also for pixel defects and image quality deterioration that occur during use, by updating the information relating to the pixel defects.

As a result, it becomes possible to make the liquid crystal panel inconspicuous while allowing the pixel defect. That is, a liquid crystal panel having a pixel defect can be used as a good product, and the yield of the liquid crystal panel is improved. It is possible to relieve the image quality deterioration and the like caused by the occurrence of a pixel defect during use, and to maintain and improve the display image quality.

Further, according to the information processing technique of the present invention, the image data to be given to the liquid crystal display device is previously set in accordance with the state of the pixel defect of the liquid crystal panel of the liquid crystal display device used for outputting the information such as the image data. The pixel defects can be made inconspicuous in the display image by processing.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing an example of the configuration of a liquid crystal display device which is an embodiment of the present invention.
The liquid crystal display device according to the present embodiment includes a pixel defect memory 1, an image processing unit 2 and a liquid crystal panel 3. The pixel defect memory 1 stores pixel defect data 1a including information regarding display states such as coordinates on the screen of pixel defects of the liquid crystal panel 3, luminance, and chromaticity. The image processing unit 2 refers to the pixel defect data 1a read from the pixel defect memory 1 and compresses and expands the input image data G in the vertical and horizontal directions of the screen without changing the image of the image to obtain the image data G1. The processed image data G1 is output to the liquid crystal panel 3 and displayed.

FIGS. 2A to 2C are conceptual diagrams showing the process of compression / expansion processing of image data in the image processing unit 2 of this embodiment. The same figure (a) has shown the coordinate of a pixel defect, brightness | luminance, and chromaticity, (b) shows the image data G before compression / expansion, (c) shows the liquid crystal panel 3 of the image data G1 after compression / expansion processing. The example of a display in is shown.

Next, an example of the operation of this embodiment will be described.
In this embodiment, as illustrated in FIG. 2A, the pixel configuration of the liquid crystal panel 3 is horizontal 1024 pixels and vertical 768 pixels, and the luminance and chromaticity are at the positions of horizontal 300 pixels and vertical 200 pixels on the liquid crystal panel 3. Has a black pixel defect. In addition, it is assumed that the image processing unit 2 is directly input with the image data G of black “A” displayed at the display position of the liquid crystal panel 3 as illustrated in FIG. 2B.

In this case, the pixel defect memory 1 has horizontal 300 as a coordinate on the screen of the pixel defect in the liquid crystal panel 3.
Pixel, vertical 200 pixel position, and brightness,
The pixel defect data 1a indicating that the chromaticity is black is stored. The pixel defect data 1a is stored in the pixel defect memory 1.
As a method of storing the information, an operator manually recognizes a pixel defect and manually inputs it, or a method of displaying a pattern for discovering the pixel defect on the liquid crystal panel 3 and providing an imaging means for recognizing the image to automatically input the pattern. Etc. are possible.

Then, the image processing unit 2 refers to the pixel defect data 1a read from the pixel defect memory 1 and retrieves the pixel data of the coordinates, luminance and chromaticity closest to the pixel defect from the input image data G. Search for. In this example, the black pixel data having the same luminance and chromaticity as the pixel defect has a horizontal value of 350 as a pixel forming the display character “A”.
It is assumed that the pixel is located at the vertical position of 200 pixels. Then, the image processing unit 2 sets 35 on the display start position side of the pixel data having the same luminance and chromaticity as this pixel defect.
Compress 0 pixels to 300 pixels (compression rate R = 350 /
400) and 624 pixels on the opposite side of the display start position from the pixel data having the same luminance and chromaticity as the pixel defect are 674.
The pixel is expanded and processed (expansion rate R = 674/624) and output. As a result, in the liquid crystal panel 3, the pixels forming the display character "A" of the processed image data G1 are displayed on the pixel defects in an overlapped manner, so that the pixel defects become invisible. Note that the compression / expansion processing of this image is performed without changing the image of the base image, so that the above-mentioned compression ratio and expansion ratio R are in a range such that the lower limit value Rmin <R <the upper limit value Rmax. To be restricted.

As a compression / expansion processing technique for the image data G, for example, the gradation integration method disclosed in Japanese Patent Application No. 5-251363 filed by the applicant of the present invention can be used.

FIG. 3 is a conceptual diagram showing an example of processing in the image processing unit 2 when there are a plurality of pixel defects in the liquid crystal panel 3. That is, in FIG. 3, the liquid crystal panel 3 has positions of 350 pixels horizontally and 200 pixels vertically,
There are pixel defects (black) at two positions of 800 pixels horizontally and 500 pixels vertically.
On the other hand, a case is shown in which the display character “A” of the image data G including the black pixel data is output at the position of horizontal 400 pixels, vertical 200 pixels, and the position of horizontal 700 pixels, vertical 500 pixels.

In this case, the image processing unit 2 compresses the image data G in the horizontal direction when x≤350 (compression rate R1 = 350/400), 350 <x≤800.
Then, it is extended horizontally (extension rate R2 = 450/30
0), x> 800, compression in the horizontal direction (compression rate R3 =
The image data G1 is generated by performing the process of (1024-800) / (1024-700) and is given to the liquid crystal panel 3. At this time, the lower limit value Rmin <R1, R2, R3 <the upper limit value R is set so that the image data G1 does not become unnatural.
max and | R1−R2 | <difference upper limit value R _D ma
x, | R2-R3 | <limit upper limit value R _D max.

As a result, as illustrated in FIG. 3C, the two pixel defects are buried and overlapped with the pixel data (black) of the processed image data G1 and cannot be seen as defects. .

Although FIG. 3 shows the case where the compression and expansion ratios in the respective areas delimited by the positions of the pixel defects are fixed and processed, as illustrated in FIG. The compression rate and the expansion rate may be interpolated between them. That is, in FIG. 4, in the horizontal direction within the rectangular area including two defects, as shown in Equations 1 and 2 in the figure, the compression rate and the expansion rate are calculated by the linear function of the pixel position y in the vertical direction. By interpolating, a smoother compression / expansion process is realized.

That is, equations 1 and 2 are y <200.
Compression ratio (350/40) at both ends of the region of y ≦ 500
The compression ratio and the expansion ratio are proportionally divided between 0) to the expansion ratio (800/700) so that a smooth compression / expansion result can be obtained.

Also in this case, the values of the compression ratio and the expansion ratio R are set so that the processed image data G1 is not unnaturally displayed.
And rate of change of R in interpolation processing dR (y) / dy
Is Rmin <R <Rmax, | dR (y) / dy | <
A limit is added so that the upper limit value R _Di max of the change rate is obtained.

For the sake of simplicity in the above description, the vertical coordinate of the pixel data which is composed of the unprocessed image data G and is superimposed on the pixel defect is the same as the pixel defect position. The same compression / expansion processing as in the horizontal direction is performed in the vertical direction.

Further, even if there is no pixel data having the same luminance and chromaticity as the pixel defect, compression / expansion processing is performed so that the pixel data having the closest luminance and chromaticity overlaps with the pixel defect.
It is possible to make pixel defects less noticeable, and
Even if there are multiple pixel defects and it is difficult to make them unnoticeable by compression / expansion processing without changing the image of the underlying image, prioritize the most prominent pixel defects and make them as conspicuous as possible. By eliminating them, the number of pixel defects that cause visual noise can be apparently reduced.

FIG. 5 shows the image data G while determining the plurality of N pixel defects and the similarity of the display state such as the luminance and chromaticity in the pixel data in the unprocessed image data G. FIG. 6 is a conceptual diagram showing an example of a determination table set in the pixel defect memory 1 when determining the processing method of FIG. 6, and FIGS. 6 and 7 are flowcharts showing an example of determination processing using this determination table. is there.

For each of a plurality of pixel defects, the determination table shows the coordinates (x, y) of the pixel defect, the color, the brightness (R, G, B), and the pixel data included in the input image data G1. Of these, the pixel defect having the closest display position distance and the difference in display state (color, brightness) is stored as a pair, and the distance dr to the pixel defect, the display state proximity dc, and further, The rank C determined based on the dr and dc is set. And finally,
The compression rate and the expansion rate are determined in the image processing unit 2 so that the pixel defects are closest to each other in order of dr and dc so that they overlap each other. This determination process is performed by a series of processes shown in FIGS. 6 and 7.

That is, first, the worst values are set in dr and dc of the entry of the pixel defect data (step 101). That is, in the case of the present embodiment, since the screen size of the liquid crystal panel 3 is 1024 × 768, the diagonal distance 1280 of this screen is taken as the worst value of the distance d.
Set to r. Similarly, in this embodiment, it is assumed that the brightness of R, G, and B is displayed in 16 steps of 0 to 15, and for simplicity,
If the closeness of the display state is the distance in the three-dimensional space of R, G, and B, the square root of 16 ² +16 ² +16 ² ≈27.7 is set in dc. Needless to say, dc may be determined according to the actual human visual characteristics.

Next, the pixel position x, y is initialized to (1, 1) at the upper left of the screen (step 102), and the pixel data D (x, y) displayed at the x, y position of the image data G.
Is input (step 103), and the first pixel defect (No.
= 1) is set (step 104).

Then, dr, DC are calculated for this pixel defect and D (x, y) (step 105) and compared with dr, dc of each entry already set in the judgment table (step 106), If it is smaller than the known one, the pixel defect No. The entries dr and dc are updated (step 107).

The operations of steps 105 to 106 are executed for all pixel defects (steps 108 and 10).
9) Further, the operations of steps 103 to 109 are repeated for one horizontal line (steps 110, 1).
11) When one line is completed, the display position y for one line is advanced in the vertical direction (steps 112 and 113), 1
The processes of steps 103 to 109 are executed for all pixel data of 024 × 768 for one frame.

After that, the pixel data of the image data G is ranked C in order from the pixel defect closest to dc and dr.
Is added (step 114), the compression / expansion ratio is determined in order from the highest rank (step 115), and the dr at the rank C is set to 0 (step 116). Are drastically recalculated (step 117), and the rank C is reset for the pixel data of ranks C + 1 and later (step 118).

Then, the rank C is further advanced (step 1
(19, 120), the compression / expansion ratio is determined so as to set dr to 0 (step 121), and the compression / expansion process of the pixel data at each rank C is reasonably matched with the screen configuration based on the already-processed compression / expansion ratio. Check whether or not (step 12
3) If they do not match, the relief processing of the pixel defect of the order is abandoned (step 122), and if they match, they coexist with the screen configuration based on the already processed compression / expansion rate (step 1).
23). This coexistence is performed by the processing of FIGS.

When the processing of steps 117 to 124 is completed for all the ranks in step 119, the procedure returns to step 102 of FIG. 6 to input the first pixel data of the next frame, and the series of processing described above. repeat.

By such processing, a plurality of pixel defects can be reasonably buried in the compressed and expanded image data G1 and can be displayed inconspicuously.

That is, according to the liquid crystal display device of the present embodiment, pixel defects can be made inconspicuous in a liquid crystal display device such as a workstation or a personal computer that frequently displays a still image, and the yield of the liquid crystal panel can be reduced. It is possible to improve the cost and reduce the cost. Also, the liquid crystal panel 3
By allowing the presence of the pixel defect in the liquid crystal panel 3, the yield and the display image quality of the liquid crystal panel 3 can be improved without unnecessarily complicating the manufacturing process and the circuit structure of the liquid crystal panel 3.

Further, in accordance with a new pixel defect, deterioration of image quality, or the like which newly occurs with the lapse of use time, information on the pixel defect can be added to the pixel defect memory 1 to easily relieve the life of the liquid crystal display device. It is possible to realize extension and prevention of image quality deterioration.

(Second Embodiment) Next, an information processing apparatus which is another embodiment of the present invention will be described. FIG. 8 is a block diagram showing an example of the configuration of the information processing apparatus of this embodiment.

The information processing apparatus according to this embodiment includes a drawing unit 7, a frame memory 8, and a liquid crystal display device 9 for displaying the pixel data of the frame memory 8 on the liquid crystal panel 3 as they are.
Is included. The drawing unit 7 includes a pixel defect memory 1
Are connected.

The pixel defect memory 1 is a means for storing the on-screen coordinates, luminance, and chromaticity information of the pixel defect of the liquid crystal panel 3, and the drawing unit 7 has the pixel defect memory 1
The pixel defect data 1a read from the frame memory 8 is referred to based on the drawing command input from the host device.
Is a means for expanding the image data. Although not shown in particular, the host device for the drawing unit 7 refers to a functional module such as a central processing unit connected by a bus or a communication line.

The frame memory 8 stores the image data at addresses corresponding to the display coordinates of the liquid crystal panel 3, and the image data expanded in the frame memory 8 is output to the liquid crystal panel 3 for display. Here, when the drawing unit 7 develops the image data in the frame memory 8, the pixel data of the coordinates, luminance, and chromaticity closest to the pixel defect are set to the coordinates of the pixel defect of the liquid crystal panel 3 as in the first embodiment. The image data of the peripheral portion is compressed and expanded so that the address of the corresponding frame memory 8 is stored. By doing so, it is possible to superimpose and display the pixel data of the luminance and chromaticity closest to the pixel defect on the pixel defect of the liquid crystal panel 3, and it becomes possible to make the pixel defect inconspicuous.

Further, in the case of this embodiment, the compression / expansion processing for embedding the pixel defect in the image data is performed on the higher-order drawing unit 7 side independently of the liquid crystal display device 9. For example, depending on the image data and usage,
You can suppress compression / decompression at all, the type of image data,
Flexible processing such as changing the algorithm of compression / expansion processing according to the processing capacity of the drawing unit 7 and the like becomes possible.

[0046]

According to the liquid crystal display technology of the present invention, the yield of liquid crystal panels can be improved by allowing the presence of pixel defects in the liquid crystal panel and making the presence of pixel defects inconspicuous. To be Further, by allowing the existence of pixel defects in the liquid crystal panel, the yield and display image quality of the liquid crystal panel can be improved without unnecessarily complicating the manufacturing process, circuit structure, etc. of the liquid crystal panel. Is obtained. In addition, it is possible to remedy the occurrence of pixel defects and image quality deterioration during actual use of the liquid crystal panel.

Further, according to the information processing apparatus of the present invention, it is possible to maintain and improve the image quality of the display image without being affected by the presence of pixel defects in the liquid crystal panel of the liquid crystal display device. Is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a liquid crystal display device which is an embodiment of the present invention.

2A to 2C are conceptual diagrams showing a process of compressing and expanding image data in a liquid crystal display device which is an embodiment of the present invention.

3A to 3C are conceptual diagrams showing a process of compression / expansion processing of image data in a liquid crystal display device which is an embodiment of the present invention.

FIG. 4 is a conceptual diagram showing an example of compression / expansion processing of image data in a liquid crystal display device which is an embodiment of the present invention.

FIG. 5 is a conceptual diagram showing an example of a determination table in the liquid crystal display device which is an embodiment of the present invention.

FIG. 6 is a flowchart showing an example of determination processing in the liquid crystal display device which is an embodiment of the present invention.

FIG. 7 is a flowchart showing an example of determination processing in the liquid crystal display device which is an embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of an information processing apparatus that is an embodiment of the present invention.

[Explanation of symbols]

1 ... Pixel defect memory, 1a ... Pixel defect data,
2 ... Image processing unit, 3 ... Liquid crystal panel,
7 ... Drawing unit, 8 ... Frame memory, 9 ...
..Liquid crystal display device

Claims (5)

[Claims] 1. Compressing, decompressing and moving the image data to be displayed on the liquid crystal panel without changing the image of the image data according to the coordinates and display state of a pixel defect on the liquid crystal panel. Pixel data having the same or similar display state as the display state of the pixel defect in the pixel data group forming the image data is displayed immediately above or in the vicinity of the pixel defect. A liquid crystal display method characterized in that the liquid crystal display method is controlled as follows. 2. A liquid crystal panel, a pixel defect storage unit that stores the coordinates and display state of a pixel defect of the liquid crystal panel on the screen, and the coordinate and display state of the pixel defect and the input image data. On the basis of the pixel data group constituting the image data, the pixel data having the same or similar display state as the display state of the pixel defect is displayed immediately above or in the vicinity of the pixel defect, A liquid crystal display device comprising: an image processing unit that performs at least one process of compression, decompression, and movement on image data without changing the image of the image data and outputs the image data to the liquid crystal panel. 3. The display state includes at least one piece of information on chromaticity and luminance, and the image processing means, when there are a plurality of pixel defects, detects the individual pixel defects of the pixel data group of the image data. The pixel data having the same or similar display state is displayed immediately above or in the vicinity of the pixel defect having the highest rank, in order from the pixel defect having the highest rank, in order from the pixel defect having the highest rank. So that the image data is compressed without changing the image of the image data,
The liquid crystal display device according to claim 2, wherein a process of performing at least one process of expansion and movement is repeated. 4. A frame memory in which pixel data is written at an address corresponding to a display coordinate of the pixel data,
A liquid crystal display device having a liquid crystal panel that directly displays the pixel data read from the frame memory, a pixel defect storage unit that stores the coordinates and display state of pixel defects in the liquid crystal panel, and input image data or command. And the same or similar to the display state of the pixel defect in the pixel data group forming the image data, based on the coordinates and display state of the pixel defect in the liquid crystal panel read from the pixel defect storage means. Pixel data having the display state of is compressed with respect to the image data without changing the image of the image data so that the pixel data is displayed immediately above or in the vicinity of the pixel defect,
An information processing apparatus, comprising: an image processing unit that performs at least one process of decompression and movement and writes the frame memory. 5. The display state includes at least one piece of information on chromaticity and luminance, and the image processing means, when there are a plurality of pixel defects, detects the individual pixel defects of the pixel data group of the image data. The pixel data having the same or similar display state is displayed immediately above or in the vicinity of the pixel defect having the highest rank, in order from the pixel defect having the highest rank, in order from the pixel defect having the highest rank. So that the image data is compressed without changing the image of the image data,
The information processing apparatus according to claim 4, wherein the operation of performing at least one of expansion and movement is repeated.