JP2008191238A - Dot matrix type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dot matrix type display device capable of suppressing a decrease in display quality even when a display element includes a pixel portion having a defect. <P>SOLUTION: A dark-spot correcting circuit 14 holds coordinate data of a defective pixel portion having a dark spot, counts coordinate positions of respective pixels of an input monochromatic video image signal based upon a synchronizing signal of a video image signal, and compares the count data with the coordinate data to detect a pixel corresponding to the defective pixel portion from the input video image signal. When the detected pixel corresponding to the defective pixel portion is a pixel of white display, the dark-spot correcting circuit 14 converts the pixel into a pixel of black display. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dot matrix type display device using a liquid crystal display element or the like.

  Conventionally, a dot matrix type display device using a liquid crystal display element or a plasma display element is known as a display device for displaying an image.

  In an active matrix display device typified by a TFT (Thin Film Transistor) liquid crystal panel, a TFT or the like is used as a switching element to control one dot. By using TFTs, etc., there is an advantage that high-speed control can be performed in dot units. On the other hand, if the switching element is defective, the dots cannot operate normally and always light up or not light up at all. . These defects are called pixel defects.

  As described above, it is difficult to completely eliminate the pixel defect due to the structure using the switching element. Therefore, at present, certain pixel defects are allowed based on the standards of each panel manufacturer in consideration of yield and display quality.

  Because of this situation, it is well known that pixel defects are generally present in TFT liquid crystal panels and the like.

  Accordingly, various liquid crystal display elements have been proposed that eliminate defects in an image by compensating for the defect during the manufacturing process even if a defect occurs in the manufacture of the liquid crystal display element. In such a liquid crystal display element, the switching elements constituting the pixel portion are made redundant, that is, when a failure occurs, an overlapping switching element and wiring for repairing are formed. The display elements have different configurations (for example, see Patent Document 1).

By the way, as in Patent Document 1, in order to provide switching elements with redundancy, it is necessary to manufacture a redundant switching element. For this reason, it is difficult to reduce the pixel size and reduce the density and to repair the short circuit or the open part, it is necessary to perform defect inspection and repair in the manufacturing process of the display element. For this reason, an apparatus and man-hours for inspection and repair are required, and the manufacturing process of the display element becomes complicated.
Japanese Patent Laid-Open No. 2004-61698

  On the other hand, in the case of a display element that does not repair defects as described above in the manufacturing process, it is impossible to deal with defects in the pixel portion of the completed display element. In particular, when at least one of the R, G, and B of the pixel portion of the display element has a dark spot defect, since the pixel portion having the dark spot defect is colored when white display is performed, the display quality is deteriorated. There was a problem.

  The present invention has been made in view of the above, and an object of the present invention is to provide a dot matrix display device capable of suppressing a reduction in display quality even when a pixel portion having a defect is included in a display element. .

  In order to achieve the above object, a dot matrix display device according to the present invention is a dot matrix using a display element in which a plurality of pixel portions each including three dots for displaying red, green, and blue are arranged in a matrix. In the display device, when one or a plurality of defective pixel portions in which at least one dot is a dark spot display is included in the plurality of pixel portions, the defective pixel portion of the display element Coordinate data storage means for storing coordinate data including the coordinate position and information on the number of defective pixel portions in advance, and the coordinate position of each pixel in the monochrome video signal input from the outside to the dot matrix display device Coordinate counter means for counting based on a synchronizing signal of a video signal, count data by the coordinate counter means, and the coordinate data storage means Compared with the stored coordinate data, the coordinate data comparing means for detecting the pixel corresponding to the defective pixel portion from the input video signal, and the defective pixel portion detected by the coordinate data comparing means When the corresponding pixel is a pixel for white display, video signal conversion means for converting the pixel into a pixel for black display is provided.

  Since the dot matrix type display device of the present invention corrects the pixel of the video signal corresponding to the defective pixel portion using the coordinate data of the defective pixel portion having a dark spot, the display element includes the defective pixel portion. Even in this case, it is possible to suppress deterioration in display quality.

  Hereinafter, the best mode for carrying out the dot matrix type display device of the present invention will be described with reference to the drawings.

  First, pixel defects in a display panel such as a TFT liquid crystal panel will be described with reference to FIGS. In the conventional dot matrix type display device as shown in FIG. 1, a video signal input from the outside is displayed on the display panel 12 after the resolution is converted by the resolution conversion IC 11 to match the resolution of the display panel 12. . The power supply circuit 13 supplies power input from an external power supply to each unit of the apparatus to operate each unit.

  The display panel 12 has a plurality of pixel portions arranged in a matrix, and as shown in FIG. 2, the pixel portion displays dots 21 for displaying red, dots 22 for displaying green, and blue. Dot 23.

  There are two types of pixel defects, dark spots and bright spots. When the image of the dot matrix display device is monochromatically displayed (red, green, or blue) on the entire surface, a dark spot is a pixel defect that does not light due to a defective dot and only that dot becomes black. On the other hand, when the image of the dot matrix display device is displayed in black on the entire surface, it is lit due to a defective dot, and a pixel defect in which only red, green, blue, etc. are displayed is a bright point.

  In the case of a pixel defect of a dark spot, for example, when the dot 21 displaying red in the pixel portion has a defect, the pixel portion is displayed in black as shown in FIG. Therefore, when a white display is attempted, the pixel portion is displayed in cyan as shown in FIG.

  In this way, in the case of a pixel defect of a dark spot, when the entire surface is displayed in white, the pixel portion having a dark spot is colored and displayed under the influence of a defective dot. This means that the dark spot is not only that the defective dot becomes black, but may be colored depending on the display content. For this reason, for example, when an image is expressed in shades of white and black, there is a problem that display quality is deteriorated due to pixel defects that are colored and displayed.

  In applications that generally require high-quality display, pixel defect standards may be set strictly. In this case, panel manufacturers inspect and sort display devices to meet standards. Since there is a limit to the means for suppressing pixel defects, the current situation is that screening is performed as a practical solution. However, the more severe management of pixel defects in the display device, the greater the influence on the unit price of the display device, for reasons such as a decrease in yield and an increase in the selection process. Therefore, in a device that requires high-quality display, the trade-off relationship between unit price and pixel defect is always a problem.

  Therefore, the present invention provides an inexpensive control function in an electric circuit, converts it into an image that does not hinder display even in a display device with a dark spot, and suppresses deterioration in display quality.

  FIG. 3 is a block diagram showing the configuration of the dot matrix display device according to the embodiment of the present invention. In the constituent elements of the present embodiment shown in FIG. 3, the same constituent elements as those in FIG.

  As shown in FIG. 3, the dot matrix display device according to the present embodiment includes a resolution conversion IC 11, a display panel 12, a power supply circuit 13, and a dark spot correction circuit 14.

  The resolution conversion IC 11 converts the resolution of a video signal input from the outside so as to match the resolution of the display panel 12. Here, in the present embodiment, when an image is expressed in shades of white and black, it is input for the purpose of suppressing deterioration in display quality due to colored display of a defective pixel portion having a dark spot. Assume that the video signal is monochrome.

  The display panel 12 displays the video signal from the dark spot correction circuit 14. In the display panel 12, a plurality of pixel portions are arranged in a matrix, and the pixel portion displays dots 21 for displaying red, dots 22 for displaying green, and blue as shown in FIG. Dot 23.

  The power supply circuit 13 supplies power input from an external power supply to each unit of the apparatus to operate each unit.

  The dark spot correction circuit 14 converts a pixel that is originally colored under the influence of a dark spot, a kind of pixel defect of the dot matrix display device, into a black display.

  FIG. 4 is a block diagram showing the configuration of the dark spot correction circuit 14 of the dot matrix type display device shown in FIG. As shown in FIG. 4, the dark spot correction circuit 14 includes a coordinate data control circuit 141, a coordinate data storage nonvolatile memory 142, a coordinate counter circuit 143, a coordinate data comparison circuit 144, and a video signal conversion circuit 145. Prepare.

  The coordinate data control circuit 141 acquires coordinate data acquired by a setting personal computer (not shown) via a communication line (not shown) such as RS232C, and stores the coordinate data in a nonvolatile storage for coordinate data. Transfer to memory 142. Here, the coordinate data includes information on the coordinate position and the number of defective pixel portions in the display panel 12 of the defective pixel portion having a dark spot in at least one dot among the pixel portions of the display panel 12, and for setting. It is acquired by using a test image by a personal computer.

  When the coordinate data output command is input from the coordinate data comparison circuit 144, the coordinate data control circuit 141 acquires the coordinate data from the coordinate data storage nonvolatile memory 142 and outputs the coordinate data to the coordinate data comparison circuit 144.

  The coordinate data storage nonvolatile memory 142 stores coordinate data when receiving an input command from the coordinate data control circuit 141, and outputs coordinate data when receiving an output command from the coordinate data control circuit 141. Since the coordinate data storage non-volatile memory 142 is a non-volatile memory, the coordinate data can be retained even when the power of the dot matrix display device is turned off.

  The coordinate counter circuit 143 operates a built-in horizontal counter and vertical counter (not shown) using the horizontal synchronization signal and the vertical synchronization signal of the video signal input from the resolution conversion IC 11 as triggers. The horizontal counter is incremented every time a video signal is input, and the vertical counter is incremented every time a video signal is input for one line. By executing the count in synchronization with the video signal, the matching between the coordinate data and the actual video signal is performed, and the pixel that needs to be corrected can be appropriately converted.

  The coordinate data comparison circuit 144 compares the count data from the coordinate counter circuit 143 with the coordinate data acquired via the coordinate data control circuit 141, and determines whether or not the input video signal is a pixel that needs to be corrected. Judging. If the pixel requires correction, a command is output to the video signal conversion circuit 145 to execute correction, and the command is output to the video signal conversion circuit 145 so as not to correct unless the pixel requires correction.

  The video signal conversion circuit 145 converts and outputs the video signal so that the video signal needs to be displayed in black according to the instruction from the coordinate data comparison circuit 144, and the pixel that does not need to be corrected does not convert the video signal. Output.

  Next, the operation of the dot matrix display device according to this embodiment will be described.

  First, a procedure for acquiring coordinate data of dark spots will be described. First, a video signal of an inspection image including a cursor-like pointer for specifying coordinates is supplied from a setting personal computer to a dot matrix display device, and a single color display (red, green, or blue) is displayed on the display panel 12. ) And presence of the defective pixel part which has a dark spot is confirmed by an operator's visual observation.

  When there is a defective pixel portion, the pointer is appropriately moved to the position of the defective pixel portion by the operation of the operator. Then, the setting personal computer acquires information on the coordinate position, and accumulates coordinate data including information on the coordinate position and the number of defective pixel portions. In addition, you may acquire the information of the coordinate position of a dark spot using measuring instruments, such as a camera, instead of an operator's visual observation.

  When the coordinate data is stored in the setting personal computer, the coordinate data control circuit 141 acquires the coordinate data from the setting personal computer and transfers the coordinate data to the coordinate data storage nonvolatile memory 142. In this way, the coordinate data of the defective pixel portion of the display panel 12 is stored in the coordinate data storage nonvolatile memory 142.

  When a monochrome video signal and its horizontal synchronization signal and vertical synchronization signal are input from the outside, the resolution conversion IC 11 converts the resolution of the input video signal so as to match the resolution of the display panel 12, and performs resolution conversion. The video signal and its horizontal synchronization signal and vertical synchronization signal are output to the dark spot correction circuit 14.

  Then, as shown in FIG. 5, the coordinate counter circuit 143 operates a built-in horizontal counter and vertical counter (not shown) using the horizontal synchronization signal and the vertical synchronization signal of the video signal input from the resolution conversion IC 11 as triggers. The horizontal counter is counted up each time one video signal is input, the vertical counter is counted up every time one video signal is input, and the count data is output to the coordinate data comparison circuit 144.

  The coordinate data comparison circuit 144 acquires coordinate data stored in the coordinate data storage nonvolatile memory 142 via the coordinate data control circuit 141, and compares the count data from the coordinate counter circuit 143 with the coordinate data. Then, it is determined whether or not the input video signal is a pixel that needs to be corrected. Here, if the input video signal is a pixel corresponding to a defective pixel portion having a dark spot and a pixel for white display, the coordinate data comparison circuit 144 determines that the pixel needs to be corrected. . In the example illustrated in FIG. 5, when the video signal corresponding to the coordinates (3, 2) of the defective pixel portion having a dark spot is a white display pixel, it is determined that the pixel needs to be corrected.

  If the pixel needs to be corrected, the coordinate data comparison circuit 144 outputs a command to the video signal conversion circuit 145 to execute correction for converting the pixel into a black display pixel. If not, a command is output to the video signal conversion circuit 145 so that no correction is made.

  The video signal conversion circuit 145 converts and outputs the video signal so that the video signal needs to be displayed in black according to the instruction from the coordinate data comparison circuit 144, and the pixel that does not need the correction does not convert the video signal. Output.

  6A and 6B are diagrams for explaining display correction of a defective pixel portion having a dark spot. FIG. 6A shows a display before correction, and FIG. 6B shows a display after correction. It is. When the dot 21 displaying red has a defect, when trying to display white, the defective pixel portion is displayed in cyan as shown in FIG. 6A, but as shown in FIG. 6B by correction. In black. By correcting in this way, even if a defective pixel portion having a dark spot is present on the display panel 12, it is possible to prevent color display.

  As described above, according to the present embodiment, the coordinate data of the defective pixel portion having a dark spot is stored in the coordinate data storage nonvolatile memory 142, and the coordinate data is compared with the count data of the coordinate counter circuit 143. And correcting the pixel of the video signal corresponding to the defective pixel portion using this comparison result, so that even if the display panel 12 includes the defective pixel portion, it is difficult to visually recognize the defective pixel portion. A decrease in display quality can be suppressed.

It is a block diagram which shows the structure of the conventional dot matrix type display apparatus. It is a figure for demonstrating a dark spot. 1 is a block diagram illustrating a configuration of a dot matrix display device according to an embodiment of the present invention. It is a block diagram which shows the structure of the dark spot correction circuit of the dot matrix type display apparatus shown in FIG. It is an image figure of coordinate data. It is a figure for demonstrating correction | amendment of the display of the defective pixel part which has a dark spot.

Explanation of symbols

11 Resolution conversion IC
DESCRIPTION OF SYMBOLS 12 Display panel 13 Power supply circuit 14 Dark point correction circuit 141 Coordinate data control circuit 142 Non-volatile memory for coordinate data storage 143 Coordinate counter circuit 144 Coordinate data comparison circuit 145 Video signal conversion circuit

Claims (1)

A dot matrix type display device using a display element in which a plurality of pixel portions each including three dots for displaying red, green, and blue are arranged in a matrix,
The coordinate position of the defective pixel portion in the display element and the defective pixel portion when at least one defective pixel portion in which at least one dot is a dark spot display is included in the plurality of pixel portions. Coordinate data storage means for storing in advance coordinate data including the number of pieces of information,
Coordinate counter means for counting the coordinate position of each pixel in the monochrome video signal input to the dot matrix display device from the outside based on the synchronization signal of the video signal;
Coordinate data comparison means for comparing the count data by the coordinate counter means and the coordinate data stored in the coordinate data storage means, and detecting pixels corresponding to the defective pixel portion from the input video signal;
When the pixel corresponding to the defective pixel portion detected by the coordinate data comparison unit is a white display pixel, the dot matrix includes: a video signal conversion unit that converts the pixel into a black display pixel. Type display device.

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