JP2010014801A - Brightness data acquiring device and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a luminance data acquiring device for implementing a liquid crystal display that can accurately identify the line where luminance unevenness occurs and does not cause degradation in a display image caused by unevenness in the luminance. <P>SOLUTION: The luminance data acquiring device acquires a luminance value as a luminance data, which is preliminarily set, according to the quantities of received light by a light-receiving element 102 for receiving irradiation light from a display region 101 of a TFT panel 100. Since the light-receiving element 102 comes to receive light in units of a source line and/or a gate line of the TFT panel 100, the luminance data representing the luminance value of the TFT panel 100 can be acquired in units of a source line and/or a gate line. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a luminance data acquisition device and a liquid crystal display device that acquire luminance data indicating the luminance of a display area of a liquid crystal display panel.

  In recent years, liquid crystal display devices have become thinner and larger, and their demand has increased. Along with this, higher quality display performance is required more than ever.

  However, the liquid crystal panel provided in the liquid crystal display device has uneven luminance in the display area due to some factor during production, and deteriorates the display quality. In particular, in the liquid crystal panel, the uneven luminance generated in the stripe shape is conspicuous, and the display quality is remarkably lowered by the uneven luminance in the stripe shape.

  For example, as shown in FIG. 3, in the display region 101 of the TFT panel unit 100, a region 101a whose luminance value is uniformly smaller than or larger than the reference luminance value in the arrow Y direction (the direction along the source line) is streaked. Exists. Such a streak-shaped region having a luminance value different from that of the surrounding area is hereinafter referred to as luminance unevenness 101a. Here, the reference luminance value is a luminance value obtained when the entire TFT panel is displayed with the same gradation.

  In order to eliminate the luminance unevenness, the luminance value of the video signal input to the liquid crystal panel is usually adjusted. For example, if the brightness value of the area corresponding to a certain source line is smaller than the reference brightness value, the area is judged to be darker than the surrounding area, and the brightness value of the video signal input to the source line is adjusted to be larger. On the other hand, if the luminance value of the area corresponding to the source line is larger than the reference luminance value, it is determined that the area is brighter than the surrounding area, and the luminance value of the video signal input to the source line is reduced. Adjust to. Specifically, luminance unevenness is eliminated by converting the gradation data of the video signal input to each source line in accordance with the luminance value of the region corresponding to each source line.

  As a technique for specifying the brightness unevenness, for example, there is a technique for creating data for correcting the unevenness using a measuring device that captures the entire screen of the liquid crystal panel as an image and measures the brightness state of the entire screen. is there.

  Further, the liquid crystal display panel has a problem that the luminance of the surface is lowered due to a change with time and the display quality is lowered.

In view of this, Patent Documents 1 and 2 disclose techniques for detecting the brightness of the surface of a liquid crystal panel and correcting the brightness to prevent deterioration in display quality.
JP 2001-265296 (published September 28, 2001) JP 007-34209 (released on February 8, 2007)

  By the way, as disclosed in Patent Documents 1 and 2, the luminance of the entire display screen can be detected only by detecting the luminance of the surface of the liquid crystal panel, but the luminance unevenness occurrence position, that is, the generation line (source line). Since it is difficult to accurately specify the brightness unevenness, the brightness unevenness cannot be appropriately eliminated, and there is a problem that the display image is deteriorated due to the brightness unevenness.

  In order to accurately identify the line where the uneven brightness is generated, it is conceivable that the display surface of the liquid crystal display panel is photographed with a camera or the like, and the observer himself observes the photographed image. If the number of source lines increases as in the case of a liquid crystal display panel that has advanced, it will take a very long time to identify all the luminance irregularities, and it will be difficult to accurately identify the lines where the luminance irregularities occur. The problem arises. Therefore, in this case as well, it is difficult to accurately specify the line where the luminance unevenness is generated, so that the luminance unevenness cannot be appropriately eliminated, and there is a problem that the display image is deteriorated due to the luminance unevenness.

  Further, in order to identify the line where the uneven brightness is generated, a method using mechanical processing using the above-described measuring apparatus is also conceivable. In this case as well, the above-described observer himself specifies the line where the uneven brightness is generated. As in the case, if the liquid crystal panel has a higher definition, there arises a problem that the processing time increases.

  The present invention has been made in view of the above-described problems, and its purpose is to accurately identify a line where luminance unevenness is generated in a short time and to prevent deterioration of a display image due to luminance unevenness. An object of the present invention is to realize a luminance data acquisition device capable of realizing a liquid crystal display device.

  In order to solve the above-described problem, the luminance data acquisition apparatus according to the present invention acquires a luminance value set in advance according to the amount of light received by the light receiving unit that receives irradiation light from the display area of the liquid crystal display panel as luminance data. In the luminance data acquisition apparatus, the light receiving unit receives light in units of source lines and / or gate lines of the liquid crystal display panel.

  According to said structure, the light-receiving part receives the irradiation light from a liquid crystal display panel in the source line unit and / or gate line unit of the said liquid crystal display panel, The brightness data which shows the luminance value of this liquid crystal display panel Can be obtained in source line units and / or gate line units.

  As a result, it is possible to accurately identify the luminance unevenness generation line on the liquid crystal display panel using the luminance data acquired in units of source lines and / or gate lines. As a result, it is possible to provide a liquid crystal display device that can suppress deterioration of a display image due to luminance unevenness.

  Furthermore, if the number of light receiving units is increased, the time required to acquire the luminance data of each line can be shortened, so that it is possible to quickly identify the line where the luminance unevenness occurs.

  It is preferable that the light receiving unit includes a plurality of light receiving elements provided for each source line and / or for each gate line of the liquid crystal display panel.

  In this case, since the irradiation light from the area | region corresponding to each line can be received simultaneously for every line unit, the generation | occurrence | production line of a brightness nonuniformity can be identified more rapidly. Accordingly, it is possible to realize a liquid crystal display device that accurately specifies a line where luminance unevenness is generated in a short time and does not cause deterioration of a display image due to luminance unevenness.

  In the case where the light receiving element is provided integrally with the liquid crystal display panel, it is necessary to further provide a light guide means for guiding the irradiation light from the display area of the liquid crystal display panel to the light receiving element.

  The positional relationship between the light receiving element and the light guiding means is preferably as follows.

  When the light receiving element is provided outside the display area of the display surface of the liquid crystal display panel, the light guide means emits light from the display area at a bezel portion that covers the display area of the liquid crystal display panel display surface. It preferably comprises a reflection mirror provided at a position where light is reflected and guided to the light receiving element. Here, the reflection mirror is located at the position where the incident angle to the reflection mirror and the emission angle from the reflection mirror of the irradiation light from the display area closest to the light receiving element of the liquid crystal display panel are equal in the bezel portion. It is preferable to be provided.

  Therefore, the light receiving element receives the light reflected from the reflection mirror provided in the bezel portion by the irradiation light from at least a part of the region along the corresponding source line or gate line.

  Usually, out of the luminance unevenness that occurs in the liquid crystal display panel, the conspicuous luminance unevenness occurs uniformly along the source line or the gate line. Therefore, as described above, the region along the source line or the gate line. Measuring the luminance of a part of the line is equivalent to measuring the luminance on the entire line.

  Further, the light guiding means is not particularly provided, and the light receiving element may be provided at a place where the irradiation light from the liquid crystal display panel can be directly received.

  For example, the light receiving element is a surface of the bezel portion covering the outside of the display area of the liquid crystal display panel, facing the outside of the display area of the liquid crystal display panel, and irradiation from the display surface of the liquid crystal display panel You may provide in the position which can receive light.

  As a result, it is not necessary to provide the light guide means, and the components of the luminance data acquisition apparatus can be reduced.

  As described above, if the luminance data acquisition device is used, the position of occurrence of luminance unevenness in the liquid crystal display panel can be accurately specified. Therefore, if the luminance data acquisition device is applied to the liquid crystal display device, an image with high display quality can be displayed. Is possible.

  Therefore, the liquid crystal display device of the present invention has a light receiving amount of a liquid crystal display panel, a video processing circuit that supplies a video signal to the liquid crystal display panel, and a light receiving unit that receives irradiation light from the display area of the liquid crystal display panel. And a luminance data acquisition device for acquiring a luminance value set in advance as luminance data, and the video processing circuit adjusts the luminance of the video signal using the luminance data acquired by the luminance data acquisition device. Then, the liquid crystal display panel is supplied.

  Accordingly, it is possible to suppress a decrease in display product due to luminance unevenness, and thus it is possible to realize a liquid crystal display device capable of displaying a high display product.

  As described above, the luminance data acquisition device according to the present invention acquires, as luminance data, a luminance value set in advance according to the amount of light received by the light receiving unit that receives irradiation light from the display area of the liquid crystal display panel. In the acquisition device, the light receiving unit receives light in units of source lines and / or gate lines of the liquid crystal display panel, so that the line where the luminance unevenness is generated can be identified in a short time and accurately. It is possible to provide a liquid crystal display device that does not cause deterioration of the displayed image.

  The embodiment of the present invention will be described as follows.

  FIG. 1 is a schematic cross-sectional view of a TFT panel unit 100 as a liquid crystal display device showing an embodiment of the present invention.

  As shown in FIG. 1, the TFT panel portion 100 includes a TFT portion 100c, a liquid crystal layer 100d, and a color filter 100e in order from the front glass substrate 100b side between the front glass substrate 100a and the back glass substrate 100b. It has a laminated structure.

  That is, as shown in FIG. 1, the TFT panel unit 100 includes a TFT unit 100c as a display unit that contributes to video display, a liquid crystal layer 100d provided on the back side of the TFT unit 100c, and a color filter 100e. A typical color TFT liquid crystal display panel.

  The front glass substrate 100a is provided with a light receiving element 102 for receiving irradiation light from the TFT portion 100c.

  The light receiving element 102 is provided in a place other than the display area 101 in the TFT panel unit 100, and is provided separately from the pixels 110 constituting the display area 101, for example, as shown in FIG. 2. More specifically, in FIG. 2, when the arrow X direction is the gate line direction and the arrow Y direction is the source line direction, the light receiving element 102 is the uppermost pixel 110 in the column of pixels 110 aligned in the source line direction. And one-to-one with the pixel column of each source line along the gate line.

  When the TFT panel unit 100 is configured as a liquid crystal display device, the outer periphery is covered with a chassis 11 as shown in FIG. The chassis 11 is provided with a bezel 11 a that covers an area other than the display area 101 in the TFT panel unit 100. Here, a predetermined gap is provided between the bezel 11 a and the TFT panel unit 100.

  Of the bezel 11a of the chassis 11, the surface facing the TFT panel portion 100 of the bezel 11a covering the light receiving element 102 provided on the transparent substrate 100b is irradiated from the TFT portion 100c as shown in FIG. A reflection mirror 103, which is a light guide member for reflecting light to the light receiving element 102, is provided.

  The reflection mirror 103 is disposed at a position for guiding the irradiation light from the region on the source line in the TFT unit 100 c corresponding to the light receiving element 102 to the light receiving element 102. Note that the irradiation light guided to the light receiving element 102 is preferably irradiation light from the entire region on the source line corresponding to each light receiving element 102, but if the region is on the same source line, the irradiation light from all regions Instead of irradiation light, irradiation light in a part of the region may be used.

  Note that the length of the gap between the bezel 11a and the TFT panel unit 100 takes into account the thickness of the reflection mirror 103 and the thickness at which the reflection mirror 103 can properly guide the irradiation light from the TFT unit 100c to the light receiving element 102. To be determined.

  The light receiving element 102 is composed of, for example, a photodiode or a phototransistor, and outputs an electrical signal corresponding to the amount of received light.

  In the TFT panel unit 100, the light receiving element 102 is manufactured simultaneously in the same process as the TFT element in the TFT panel. The manufacturing method of the TFT panel unit 100 including the light receiving element 102 is the same as the manufacturing method of a general TFT panel, and thus detailed description thereof is omitted.

  By the way, when video signals of the same gradation are supplied to all the source lines to the TFT panel unit 100, the luminance of the video displayed on the TFT panel unit 100 should be uniform.

  However, in the general TFT panel unit 100, the luminance is not uniform and unevenness occurs. For example, as shown in FIG. 3, in the display area 101, the unevenness has a region where the luminance value is uniformly lower or higher than the reference luminance value in the arrow Y direction (vertical direction), resulting in the luminance unevenness 101a. Recognized by the observer.

  The luminance unevenness 101a does not appear periodically, but appears irregularly in the direction of the arrow X as shown in FIG. Further, the position where the luminance unevenness 101a is generated varies depending on individual differences. For this reason, the luminance value is measured for each source line in the TFT panel unit 100, the extent to which the measured value is different from the reference luminance value is grasped for each TFT panel unit 100, and the region where the luminance unevenness 101a occurs. And the video signal input to the TFT panel 100 needs to be corrected.

  In the present embodiment, as described above, the light receiving element 102 is provided for each source line, and the irradiation light from the region corresponding to each source line is received by the light receiving element 102, and according to the amount of light received. An electrical signal is output, and this electrical signal is used as luminance data.

  An example of the liquid crystal display device using the luminance data is a liquid crystal display device shown in FIG. As shown in FIG. 4, the liquid crystal display device includes a TFT panel section 100, a timing control circuit 200, and a video signal processing circuit 300.

  The TFT panel unit 100 includes a liquid crystal display panel and the light receiving element 102 (FIG. 1) described above as a light receiving unit for measuring the luminance of the display area of the liquid crystal display panel.

  The TFT panel unit 100 is configured to perform a desired display when the video signal from the video signal processing circuit 300 is supplied via the timing control circuit 200. The timing control circuit 200 adjusts the luminance of the video signal input for each source line from the luminance value obtained from each light receiving element 102 of the TFT panel unit 100 in advance, and then converts the video signal to the TFT panel. To the unit 100. Details of the timing control circuit 200 will be described later.

  In the present embodiment, the light receiving element 102 is provided on the front glass substrate 100a as shown in FIG. 1, but the present invention is not limited to this. For example, the TFT panel portion 100 ′ shown in FIG. In addition, the bezel 11a may be provided on the opposing surface of the TFT panel portion 100. In this case, it is possible to directly receive light without reflecting the irradiation light from the display area 101 in the TFT portion 100c, and thus the number of components can be reduced.

  As shown in FIG. 6, the timing control circuit 200 includes a luminance adjustment circuit 400, a video data correction circuit 500, a panel data transmission circuit 600, and a timing generation circuit 700.

  The luminance adjustment circuit 400 is a circuit that adjusts the luminance of the video signal input to the TFT panel unit 100, and includes a color gradation expansion circuit (gradation expansion means) 401 and a memory (storage means) 402. It is out. Details of the luminance adjustment circuit 400 will be described later.

  The video signal whose luminance is adjusted for each line by the luminance adjustment circuit 400 is supplied to the video data correction circuit 200. Here, the line indicates a source line provided in the TFT portion 100a in the TFT panel portion 100.

  The video data correction circuit 500 further performs correction processing in the gamma correction circuit, the color tone correction circuit, the contour correction circuit, and the like on the video signal whose luminance has been adjusted by the luminance adjustment circuit 400, and the corrected video data is converted into the subsequent stage. This circuit supplies the panel data transmission circuit 600 and the timing generation circuit 700.

  The panel data transmission circuit 600 extracts panel data necessary for display on the TFT panel unit 100 from the corrected video data supplied from the video data correction circuit 500 and transmits the panel data to a source driving circuit (not shown). Circuit.

  On the other hand, the timing generation circuit 700 generates a timing signal for timing the panel data supplied to the TFT panel unit 100 from the timing information included in the corrected video data supplied from the video data correction circuit 500. It is.

  That is, the timing control circuit 200 appropriately corrects the luminance of the input video signal, generates panel data and a timing signal from the corrected video data, and supplies each to the source driving circuit. It has become.

  In the timing control circuit 200 shown in FIG. 6, an example in which the luminance adjustment circuit 400 is provided in the previous stage of the video data correction circuit 500 is shown, but the luminance adjustment circuit 400 is provided in the subsequent stage of the video data correction circuit 500. It may be.

  Here, the brightness adjusting circuit 400 will be described below with reference to FIGS. 7 (a) and 7 (b).

  The luminance adjustment circuit 400 includes a color gradation expansion circuit (gradation expansion means) 401 and a memory (storage means) 402 as shown in FIG.

  The color gradation extension circuit 401 is a circuit that performs an extension process on an 8-bit gradation video signal to a pseudo 10-bit gradation video signal for each line in the TFT panel unit 100 to which a video signal is input. . For example, an FRC (Frame Rate Control) circuit can be preferably used, but other circuits may be used as long as the circuit expands the gradation in a pseudo manner. For example, as an example of the FRC circuit, a circuit for performing pseudo 10-bit gradation display on the TFT panel 1 capable of displaying 8-bit gradation by dividing the time into four and expressing gradations of lower 2 bits. There is.

  As shown in FIG. 7B, the color gradation expansion circuit 401 expands an 8-bit input video signal represented by 256 gradations to 1024 gradations of 10-bit gradations and expands pseudo 1024. This is a circuit that selects 256 gradations based on the 2-bit luminance adjustment data stored in the memory 402 from the gradations and outputs a pseudo 10-bit output.

  The memory 402 is storage means for storing 2-bit luminance adjustment data set in advance for each line to which a video signal is input in the TFT panel unit 100. As the storage means, RAM, ROM or the like can be applied, but it is preferable to use a storage means with a reading speed as fast as possible.

  In the memory 402, 2-bit luminance adjustment data is stored for each source line of the TFT panel section 100 as shown in FIG.

  The color gradation expansion circuit 401 reads the luminance adjustment data stored in the memory 402 for each source line, and based on the read luminance adjustment data, the level of the video signal input to the source line. A key is assigned to one of the expanded gradations.

  Specifically, when the brightness adjustment data is 2-bit data as described above, the 2-bit data can be classified into four types of “00”, “01”, “10”, and “11”. , 4 gradations (4n gradation, 4n + 1 gradation, 4n + 2 gradation) of 10-bit video signal for one gradation of the 8-bit video signal (n gradation: n = 0 to 255) 4n + 3 gradations) is assigned.

  Here, the brightness adjustment data “00” indicates no gradation change, “01” indicates that the gradation is increased by one step when the gradation is changed to 10-bit gradation, and “10” indicates the gradation is changed. When the 10-bit gradation is set, it indicates that the level is increased by two, and “11” indicates that the level is increased by three when the gradation is set to the 10-bit level. That is, in FIG. 5, “00” is associated with the 4n gradation of the 10-bit gradation, “01” is associated with the 4n + 1 gradation, “10” is associated with the 4n + 2 gradation, “11” is associated with the 4n + 3 gradation.

  In other words, if the number of gradations of an input 8-bit gradation video signal is n = 0, there are four gradations of 0 gradation, 1 gradation, 2 gradations, and 3 gradations in the 10-bit gradation. Assigned. When the luminance adjustment data indicating that no gradation change is necessary in the source line is “00”, the 8-bit gradation video signal with n = 0 is assigned to 0 gradation of 10-bit gradation. become.

  As described above, when the brightness adjustment data is 2-bit data, one gradation is selected from four gradations for each gradation. In the case of performing, the gradation is reduced to 6-bit gradation. However, as described above, if the gradation is expanded to 10-bit gradation, the gradation can be left as 8-bit gradation.

  In this embodiment, the case where the luminance adjustment data is 2 bits has been described. However, the present invention is not limited to this. For example, the luminance adjustment data may be 4 bits. In this case, one gradation is selected from 12 gradations for each gradation. As described above, by increasing the number of bits of the brightness adjustment data, it is possible to widen the gradation correction range.

  As described above, in the present embodiment, the TFT panel unit 100 is provided with the light receiving element 102 that constitutes a luminance data acquisition device for extracting luminance data and generating luminance adjustment data. Since the luminance value of each line can be obtained from 102 and the line where the luminance unevenness is generated can be specified, the line where the luminance unevenness is generated manually when the TFT panel unit 100 is produced is automatically replaced with the line where the luminance unevenness is generated. Can be specified.

  In addition, since the light receiving element 102 remains after the production of the TFT panel unit 100, in a liquid crystal display device equipped with the TFT panel unit 100, it is possible to observe the change in luminance value of each line in real time.

  As a result, it is possible to always correctly adjust the correction amount determined with respect to the luminance unevenness periodically, and it is possible to minimize the deterioration in display quality due to secular change. As a result, the service life of the liquid crystal display device can be extended.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The present invention can be applied to a display panel in which luminance unevenness may occur, such as a liquid crystal display panel.

1, showing an embodiment of the present invention, is a schematic sectional view of a liquid crystal display device including a light receiving element. FIG. 2 is a plan view showing a positional relationship between light receiving elements and pixels in the liquid crystal display device shown in FIG. 1. It is a top view of the TFT panel part of the liquid crystal display device shown in FIG. It is a block diagram which shows the principal part structure of the liquid crystal display device shown in FIG. FIG. 5 is a schematic cross-sectional view of a liquid crystal display device including a light receiving element according to another embodiment of the present invention. FIG. 5 is a block diagram showing a main configuration of a timing control circuit provided in the liquid crystal display device shown in FIG. 4. (A) is a block diagram showing a main configuration of a luminance adjustment circuit in the timing control circuit shown in FIG. 6, and (b) explains pseudo gradation processing in the luminance adjustment circuit shown in (a). FIG. It is a figure which shows the state which stored the data for luminance adjustment in the memory with which the luminance adjustment circuit shown to Fig.7 (a) was equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Chassis 11a Bezel 100 TFT panel part 100a TFT part 100b TFT panel part 100b Transparent substrate 100c Optical sheet 101 Display area 101a Brightness unevenness 102 Light receiving element 103 Reflection mirror 110 Pixel 200 Timing control circuit 200a TFT part 201 Display area 202 Light receiving element 300 Image Signal processing circuit

Claims (6)

In a luminance data acquisition device that acquires, as luminance data, a luminance value set in advance according to the amount of light received by a light receiving unit that receives irradiation light from a display area of a liquid crystal display panel,
The luminance data acquisition apparatus, wherein the light receiving unit receives light in units of source lines and / or gate lines of the liquid crystal display panel. The light receiving part is
2. The luminance data acquisition apparatus according to claim 1, comprising a plurality of light receiving elements provided for each source line and / or for each gate line of the liquid crystal display panel. The light receiving element is provided integrally with the liquid crystal display panel,
The luminance data acquisition apparatus according to claim 2, further comprising a light guide unit that guides irradiation light from a display area of the liquid crystal display panel to the light receiving element. The light guiding means is
When the light receiving element is provided outside the display area of the display surface of the liquid crystal display panel, the bezel part covering the outside of the display area of the liquid crystal display panel display reflects the irradiation light from the display area and 4. The luminance data acquisition apparatus according to claim 3, comprising a reflection mirror provided at a position leading to the light receiving element. The light receiving element is
The position of the bezel part covering the outside of the display area of the liquid crystal display panel that faces the outside of the display area of the liquid crystal display panel and that can receive the irradiation light from the display face of the liquid crystal display panel The luminance data acquisition device according to claim 2, wherein the luminance data acquisition device is provided. A liquid crystal display panel;
A video processing circuit for supplying a video signal to the liquid crystal display panel;
The luminance data acquisition according to any one of claims 1 to 5, wherein a luminance value set in advance according to the amount of light received by a light receiving unit that receives irradiation light from a display area of the liquid crystal display panel is acquired as luminance data. With the device,
The liquid crystal display device, wherein the video processing circuit adjusts the luminance of the video signal using the luminance data acquired by the luminance data acquisition device and supplies the video signal to the liquid crystal display panel.

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