JP4691070B2 - Video signal correction apparatus, method, and program - Google Patents

Description

  The present invention relates to an apparatus, method, and program for correcting chromaticity of a video signal used in a backlight drive type liquid crystal display device.

A backlight drive type liquid crystal display device (hereinafter referred to as a liquid crystal display device) used in a field requiring a long life and high reliability is a backlight lamp tray system in which a backlight lamp can be replaced. This is proposed so that maintenance and replacement can be performed by realizing the backlight lamp in a tray system in the case of deterioration of the fluorescent lamp due to years of use, failure of the fluorescent lamp (lamp out), or the like.
In recent years, with the increase in the size of liquid crystal modules, backlight lamp trays have also been put into practical use by being mounted in a plurality of trays in a horizontal / vertical manner. One backlight lamp tray is formed by integrating a plurality of fluorescent lamps and an inverter drive circuit. For example, a liquid crystal display device in which three backlight lamp trays and a total of 18 fluorescent lamps are mounted has been proposed. Yes.

  In such a liquid crystal display device, when replacing the backlight lamp tray due to the life of the fluorescent lamp, it is recommended to replace all mounted backlight lamp trays. It is recommended that all backlight lamp trays be replaced even in the event of a failure of the fluorescent lamp on the tray. The reason for exchanging the same number of backlight lamp trays as at the end of their lifespan is that the color of the backlight lamp trays varies depending on the production time and lot (product production unit) of the fluorescent lamp parts. This is because when such a backlight lamp tray is mixed, a chromaticity difference is generated on the surface of the liquid crystal panel.

Patent documents 1 to 3 are known as conventional techniques. Patent Document 1 is a technique for adjusting the backlight so that the luminance corresponding to the color temperature of the display color is changed. Patent Document 2 discloses unevenness of the backlight according to the energization time for each area of the liquid crystal display screen. Patent Document 3 is a technique for correcting backlight brightness and display data based on measurement results in a multi-display.
JP 2007-12534 A JP 2006-330222 A JP 2001-147667 A

As described above, conventionally, the user has to replace all the backlight lamp trays even when some of the lamps have run out, and the user has a drawback that the cost for maintenance increases. In addition, since the parts supplier requires strict accuracy standards, the optical specification range of the fluorescent lamp parts cannot be expanded, and the user cannot expand the procurement source.
That is, when the backlight lamp tray replacement method is adopted in the liquid crystal display device, if only a part of the backlight lamp tray is replaced instead of the total, a subtle difference in lamp chromaticity can be recognized with the naked eye. This will be described with reference to a liquid crystal display device including three backlight lamp trays shown in FIG. For example, if the middle backlight lamp tray breaks down and the tray is replaced, the difference in chromaticity generated on the LCD panel surface due to subtle lamp chromaticity differences between the upper-middle and interrupted-lower backlight lamp trays. FIG. 15 shows a case where recognition with the naked eye is possible. For this reason, it is necessary to replace all the backlight lamp trays even if the replacement is performed due to a part of the lamps being cut. Note that the backlight lamp tray may be arranged vertically as shown in FIG. In such a case, regions with different chromaticities appear in the vertical direction.

  The present invention has been made in view of the above problems, and in the backlight drive type liquid crystal display device, the change in the color of the backlight light caused by the difference in the lamp characteristics of each light source is in units of lamp trays. The purpose is to display the screen without making the user feel uncomfortable by correcting.

The video signal correction apparatus according to the present invention includes an adjacent divided region with respect to the chromaticity measured on the surface of the liquid crystal panel for each divided region obtained by dividing the display region of the liquid crystal panel according to the arrangement of a plurality of backlight lamps. Storage means for preliminarily storing adjustment parameters set so as to reduce the chromaticity difference between them to a predetermined value or less, and the gradation of the RGB components of the video signal corresponding to the designated divided area among the divided areas a first correcting means for adjusting, based on the adjustment parameter, see contains the boundary between the first divisional area and a second partitioned area adjacent to the divided area where the video signal is adjusted, the first When adjusting the gradation of the RGB components of the video signal corresponding to the synthesis area, which is an area obtained by synthesizing the first area that is a part of the divided area and the second area that is a part of the second divided area, the first region and before Symbol Serial second region to, and a second correction means for performing an adjustment on the basis of the said adjustment parameter that is different between the first region and the second region.

The video signal correction method according to the present invention includes a segmented region adjacent to a chromaticity measured on the surface of the liquid crystal panel for each segmented region in which the display region of the liquid crystal panel is segmented according to the arrangement of a plurality of backlight lamps. A process of obtaining the adjustment parameter from storage means for storing in advance an adjustment parameter set so as to reduce the chromaticity difference between the predetermined values or less, and a video corresponding to the designated divided area among the divided areas the gradation of the RGB components of the signals, between the first step of adjusting, based on the adjustment parameter, and the first partitioned area and a second partitioned area adjacent to the divided area where the video signal is adjusted look including the border, RGB component video signals corresponding to the first region and the synthesis area is synthesized region and a second region which is a part of the second segment area which is a part of the first segment area Floor of When adjusting, over the previous SL first region and the second region, having a second step of performing an adjustment on the basis of the said adjustment parameter that is different between the first region and the second region.

The program according to the present invention allows the computer of the video signal correction apparatus to perform chromaticity measured on the surface of the liquid crystal panel for each divided area obtained by dividing the display area of the liquid crystal panel according to the arrangement of the plurality of backlight lamps . A step of acquiring the adjustment parameter from a storage unit that stores in advance an adjustment parameter set so as to reduce a chromaticity difference between adjacent divided regions to a predetermined value or less; and a specified division among the divided regions the gradation of the RGB components of the video signal that corresponds to the region, a first step of adjusting, based on the adjustment parameter, a second segment adjoining the first segment area and the division area where the video signal is adjusted look including the border between the regions, the first region and the synthesis area is synthesized region and a second region which is a part of the second segment area which is a part of the first segment area When adjusting the gradation of the RGB components of the corresponding video signal, over the previous SL first region and the second region, to perform the adjustment on the basis of the said adjustment parameter that is different between the first region and the second region And a second step .

  Therefore, according to the present invention, the gradation of the RGB components of the video signal corresponding to the designated divided area among the divided areas obtained by dividing the display area of the liquid crystal panel according to the arrangement of the plurality of backlight lamps is adjusted. , By adjusting the gradation of the RGB component of the video signal corresponding to the composite region including the boundary line between the segmented region where the video signal is adjusted and the segmented region adjacent to the segmented region, Since a subtle difference in color generated in the backlight lamp lamp tray can be corrected and chromaticity correction can be performed in the liquid crystal display device, only the defective backlight lamp tray needs to be replaced.

  First, a configuration of a liquid crystal display device according to an embodiment of the present invention will be described with reference to FIG. The liquid crystal display device includes a control terminal 100, a control circuit 200, and an LCD module 300.

  The control terminal 100 is used for a user to perform an OSD (On Screen Display) operation. In this case, the user operates the buttons provided on the control terminal 100 while viewing the setting screen displayed on the image by the video signal input to the liquid crystal display device, and gives an input to the control circuit 200. It is.

The control circuit 200 includes a video signal input unit 210, a control basic unit 220, and a video signal output unit 230.
A digital signal (for example, a digital signal in which gradation is expressed by 8 bits for each RGB) or an analog signal is input to the video signal input unit 210.
The control basic unit 220 includes a dimming control unit 221, a control unit 222, a color control unit 223, and a chromaticity correction unit 224.
When setting is performed by OSD operation using the control terminal 100, the dimming control unit 221 sends a control signal for adjusting lamp luminance to the dimming circuit unit 310 of the LCD module 300. This interface uses an analog DC voltage. This control can be realized using an MPU (microprocessing unit, that is, a microcomputer control circuit).
The color control unit 223 converts the output level for the input image data from the video signal input unit 210. This control is realized by an FPGA (field-programmable grid array (ie, logic circuit)), and conversion parameter setting and control can be realized by using an MPU (microcomputer control circuit).
When information necessary for determining a register value representing the amount of chromaticity correction is input by an OSD operation using the control terminal 100, the chromaticity correction unit 224 receives a predetermined area from the display area of the liquid crystal panel. Correct the chromaticity of the video signal. Alternatively, means for remotely connecting to the control unit 222 through RS-232C or the like may be provided, and the above register value of the chromaticity correction unit 224 may be set directly. In one embodiment, the chromaticity correction unit 224 is implemented as a logic circuit. Alternatively, a program for causing the MPU to execute chromaticity correction processing may be installed.
The video signal output unit 230 outputs the video signal processed by the control basic unit 220 to the video signal input unit 340 of the LCD module 300 as a digital signal. This processing is realized by an FPGA, and conversion parameter setting and control can be realized by using an MPU.

The LCD module 300 includes a dimming circuit unit 310, a power supply unit 320, a backlight lamp unit basic unit 330, a video signal input unit 340, a control basic unit 350, and a drive circuit basic unit 360.
The dimming circuit unit 310 controls the lamp luminance by a control signal input from the dimming control unit 221. This controls the lamp luminance of the backlight lamp unit 332 by adjusting the duty ratio of the control signal input to the backlight inverter unit 331 of the backlight lamp unit basic unit 330. As described above, one backlight lamp tray is configured by integrating a plurality of fluorescent lamps and an inverter drive circuit, and one backlight lamp tray corresponds to the backlight lamp unit basic unit 330, and The plurality of fluorescent lamps in the backlight lamp tray correspond to the backlight lamp unit 332, and the inverter drive circuit of the backlight lamp tray corresponds to the backlight inverter unit 331. Therefore, in the embodiment having three backlight lamp trays, there are three backlight lamp unit basic units 330, and one dimming circuit unit 310 controls them.
The control basic unit 350 includes a basic unit 351, a voltage control unit 352, and a gradation control unit 353. The gradation control unit 353 controls gamma characteristics that are the basis of color temperature.
The drive circuit basic unit 360 displays an image under the control of the source drive circuit units 361 and 362 and the gate drive circuit units 363 and 364. The drive circuit basic unit 360 corresponds to a liquid crystal panel.

Processing that affects the chromaticity generated on the surface of the liquid crystal panel is performed by the dimming control unit 221, the color control unit 223, and the chromaticity correction unit 224. This will be described by comparing the current general process shown in FIG. 2 with the process of the present embodiment shown in FIG.
2, when a video signal is input to the liquid crystal display device, a dimming control process for correcting the lamp luminance of the backlight lamp and a color control process for adjusting the chromaticity of the video signal are performed. The light output from the backlight lamp by the light control process and the light output from the liquid crystal panel by the color control process are combined to generate chromaticity on the surface of the liquid crystal panel. Note that the chromaticity adjustment in the color control processing is conventionally performed by correcting the chromaticity between monitors or correcting the chromaticity for the master color. This is done on the assumption that the chromaticity of the liquid crystal panel surface is always within a certain range, so if there is a variation in chromaticity on the liquid crystal panel surface between backlight lamp trays, it cannot be easily corrected. It was.
On the other hand, in the processing of the present embodiment shown in FIG. 3, chromaticity correction processing for correcting the chromaticity of the video signal adjusted by the color control processing is performed. This process adjusts the video signal to correct the chromaticity difference due to the backlight lamp tray.
2 and 3 do not represent the input / output relationship of the signals, but the light output from the backlight by the dimming control processing and the color control processing (color control processing and chromaticity correction processing in FIG. 3). It schematically shows that light output from the liquid crystal panel is combined to produce chromaticity on the surface of the liquid crystal panel.

Hereinafter, processing by the chromaticity correction unit 224 will be described. FIG. 4 shows an example in which a chromaticity difference is generated on the surface of the liquid crystal panel as a problem because only the lower backlight lamp tray is replaced. For example, as shown in FIG. 4, when the liquid crystal display device displays 2048 lines in the vertical period of the video signal and 2048 pixels in the horizontal period, that is, has an effective display area of 2048 × 2048 pixels. As a segmented area defined by segmenting the display area of the liquid crystal panel according to the physical arrangement of the lamps, the 2048 lines are segmented, and the upper (U) and lower (D) sections are each 683 lines. The section (M) is set to 682 lines. At this time, as shown in FIG. 5, the upper stage (U) and the middle stage (M) have substantially the same chromaticity, and the lower stage (D) is different in chromaticity. The chromaticity measured on the surface of the liquid crystal panel is, for example, It is a value like
Upper (U) center: white (0.3089, 0.3117)
Middle (M) center: white (0.3089, 0.3117)
Lower stage (D) Center: White blue system (0.3014, 0.3161)
Table 1 shows values measured for a plurality of lines in the effective display area of the liquid crystal display device. The line numbers shown in FIG. 5 and Table 1 are given so as to increase from the bottom to the top, and the chromaticities at the middle (M) center and the bottom (D) center are 1024 in Table 1, respectively. The chromaticity of 341 lines was adopted.

  In the case shown in FIG. 5 and Table 1, the chromaticity generated on the surface of the liquid crystal panel by the lower (D) backlight lamp tray is white-blue, so that the white color of the same color as the upper (U) and middle (M) By doing so, the chromaticity difference on the surface of the liquid crystal panel can be made constant. Generally, the chromaticity difference perceived by the human eye is a difference of 0.001 to 0.0015, and the goal is to make the chromaticity difference 0.0015 or less.

Therefore, in the present embodiment, as shown in FIG. 4, first correction means for defining upper, middle, and lower sections corresponding to the arrangement of the backlight lamp tray and correcting the chromaticity in the range of the backlight lamp tray unit, A video signal to be input to the liquid crystal panel is corrected by providing the chromaticity correction unit 224 with a second correction unit that corrects the chromaticity of the combined section by providing a composite section where the chromaticities of each stage intersect. In the example shown below, the composite section is a section composed of a predetermined number of lines above and below the upper and middle boundary lines, and a section composed of a predetermined number of lines above and below the middle and lower boundary lines. As described above, the second correction unit performs synthesis of the sections that are individually chromatically corrected by the first correction unit by setting a synthesis section that spans the sections that are individually chromaticity corrected by the first correction unit. be able to.
Note that the region to be corrected by the first correction unit may be a region in which the display region of the liquid crystal panel is divided according to the arrangement of the plurality of backlight lamps, and the region to be corrected by the second correction unit is It suffices if the divided areas are areas including adjacent boundary lines. For example, the number of backlight lamp trays is not limited to three. Further, even when the backlight lamp tray is arranged vertically as shown in FIG. 16, the display area of the liquid crystal panel is divided so as to correspond to this arrangement, and the divided areas include the adjacent boundary lines. It is possible to set these areas as correction targets of the first and second correction processing means.

Next, FIG. 6 and FIG. 7 show an outline of the processing (correction processing 1 and correction processing 2) by the first and second correction means. 6 and 7, the x-axis represents the line number from the lowest stage of the effective display area of the liquid crystal display device, and the y-axis represents the values of chromaticity Wx and Wy. The solid lines in the graph indicate the chromaticity values Wx and Wy before the correction process, and the broken lines in the graph indicate the chromaticity values Wx and Wy after the correction process.
(1) Correction process 1: In the example of FIG. 4, the chromaticity of the lower (D) center (341 lines) that is white-blue is changed to the chromaticity of the middle (M) center (1024 lines) that is white. The processing of the lower stage (D) (1st to 683 lines) is performed.
(2) Correction process 2: When correction process 1 is performed, a chromaticity difference occurs in the synthesis section. Therefore, since the chromaticity needs to be flattened, each of the synthesis sections in the range of the inverse chromaticity shown in FIG. Perform line chromaticity correction.

  The section for performing the above correction processing is determined in advance as shown in FIGS. 8 and 9, and the information shown in Table 2 is set in the register of the chromaticity correction unit 224. Usually, the section is variable because it is set by a register. As the processing target of the correction process 2, it can be considered that the chromaticity forms an apex at the boundary line between the backlight lamp trays. Therefore, the boundary section between A and B (boundary 1A and boundary 1B in Table 2) for each boundary line. , And boundary 2A and boundary 2B).

If processing in the section including the boundary line is not required due to the backlight lamp characteristic, the correction processing may be invalidated depending on the section.
Further, correction processing may be added in a section where correction processing is performed redundantly. For example, in Table 2, the boundary 2B (483 to 683 lines) to which the correction process 2 is applied overlaps with the lower stage (1 to 683 lines) to which the correction process 1 is applied. In FIG. 8, these sections are represented in the range of 483 to 683 lines as the line processing section of the correction process 2 and are represented in the range of 1 to 683 lines as the horizontal arrow and the line processing section of the correction process 1. Corresponding to the horizontal arrow. However, if the result obtained by applying both the correction process 1 and the correction process 2 to the range of 483 to 683 lines is obtained by one correction process (assuming “correction process 2 ′”), The correction process 1 may be applied to lines 1 to 482 excluding overlapping portions, and the correction process 2 ′ may be applied to lines 483 to 683. In FIG. 8, the horizontal arrow shown in the range of 1 to 482 lines as the line processing section of the correction process 1 represents such a case. That is, the area to be subjected to the correction process 1 may be the entire area or a part of each area obtained by dividing the display area of the liquid crystal panel according to the arrangement of the plurality of backlight lamps. Including.

  FIG. 10 shows the above process by detailing FIG. The dimming control process adjusts the lamp brightness of the backlight lamp by gain adjustment. The color control process performs gain / offset adjustment of the video signal and color balance adjustment of each RGB component. In the chromaticity correction process, each of RGB components whose color balance is adjusted is divided into an upper stage (U), a middle stage (M), and a lower stage (D), and the correction process 1 described above is performed. The correction process 2 described above is performed for each of the RGB components included in the section (MD). Here, the combined section (UM) corresponds to, for example, the boundary 1A and the boundary 1B of Table 2 described above, and the combined section (MD) includes, for example, the boundary 2A and the boundary 2B of Table 2 described above. Equivalent to.

Next, how each section is corrected in the correction process 1 and the correction process 2 will be described. In the liquid crystal panel, the white chromaticity is determined by the red component, the green component, and the bluish purple component, and therefore, the chromaticity that is different for each backlight lamp tray is solved by adjusting the RGB color components.
First, the principle of converting each chromaticity with respect to color will be described with reference to FIG. FIG. 11 shows the color display of the directivity characteristic of white chromaticity by the black and white shading. The color center is white. If the color is white-blue (cyan), the chromaticity Wx is in the minus direction, so Wx may be shifted in the plus direction. Conversely, if it is white-red, Wx is in the plus direction, so Wx may be in the minus direction. If it is white-green, the chromaticity Wy is in the plus direction, so Wy may be shifted in the minus direction. On the other hand, if the color is white-purple, the chromaticity Wy is in the minus direction, so Wy may be shifted in the plus direction. Similarly, in the case of white-blue, since chromaticity Wx and Wy are in the minus direction, Wx and Wy may be shifted in the plus direction. Conversely, if it is a white-yellow system, Wx and Wy are in the plus direction, so they may be shifted to minus.
Adjustment can be made by determining a register setting value necessary for chromaticity conversion so that the directivity can be converted by a register parameter. Table 3 shows an example of chromaticity conversion in RGB single color, and Table 4 shows chromaticity correction ratios corresponding to register setting values. For example, the register setting value is adjusted by adjusting the chromaticity difference ± 0.015 of each RGB within the range of the register setting value ± 10, that is, the register setting value is changed in steps of + 0.015 / 10, and ± 0.0015 / Prepare a chromaticity conversion table with step separation. It is also possible to increase the number of steps and make finer adjustments.

An example of R color chromaticity adjustment in Table 3 is a register for shifting Wx in the plus direction when the color is white blue (cyan) and the measured chromaticities Wx and Wy are 0.285 and 0.310. The set value is 10 (according to Table 4, the corresponding chromaticity correction ratio is about 1.09), the color is white red (pink), and the measured chromaticities Wx, Wy are 0.308, 0.312 In order to shift Wx in the minus direction at a certain time, the register setting value is set to -10 (according to Table 4, the corresponding chromaticity correction ratio is about 0.9).
In the example of the chromaticity adjustment of G color, when the color tone is white purple and the measured chromaticity Wx, Wy is 0.298, 0.286, the register setting value is set to 10 in order to shift Wy in the plus direction. When the color is white-green and the measured chromaticities Wx and Wy are 0.301 and 0.321, this indicates that the register set value is set to −10 in order to shift Wy in the minus direction.
In the example of adjusting the chromaticity of the B color, when the hue is white and blue and the measured chromaticities Wx and Wy are 0.295 and 0.308, the register setting value is set to 10 in order to shift Wx and Wy in the plus direction. When the color tone is white yellow and the measured chromaticities Wx and Wy are 0.313 and 0.329, the register set value is set to -10 in order to shift Wx and Wy in the minus direction.

Since the relationship between the chromaticity differences ΔWx, ΔWy exemplified in Table 3 (difference between measured Wx, Wy and white Wx, Wy) and the register setting values for RGB chromaticity adjustment is obtained by experiment, ΔWx , ΔWy can be changed in predetermined increments to create a conversion table. Since the RGB chromaticity has a spread (depth) due to the backlight lamp characteristic, in this embodiment, as shown in Table 5, in addition to the single color adjustment register setting value, a chromaticity with which a plurality of chromaticities can be adjusted simultaneously. A directional chromaticity conversion table for selection and weighting is used. This table is stored in advance by providing storage means in the chromaticity correction unit 224. It is adjusted using the setting value of this table according to the backlight lamp characteristics. The horizontal axis of Table 5 represents the value of ΔWx in units of 0.0015, and the vertical axis represents the value of ΔWy in units of 0.0015. For example, R0, G0, and B-10 located at +10 and +10 indicate that the register set values of R, G, and B are 0, 0, and -10, respectively. Even where the values in Table 5 are omitted, an appropriate register setting value can be obtained by experiment to fill this table. In Table 5, as an example, the range of the chromaticity difference ± 0.015 is configured in increments of ± 10, but may be configured in increments of ± 20. The chromaticity correction ratio in Table 4 is different from the ratio at which the chromaticity actually changes on the liquid crystal panel surface, so this chromaticity conversion table is effective.
In the correction process 1, when the register setting value is given in this way, the gradation of each RGB component in the corresponding section is adjusted by the chromaticity correction ratio (Table 4) corresponding to the register setting value, and thereby the color The degree is corrected.

  In the correction process 2, after executing the correction process 1, the chromaticity is more smoothly interpolated in the boundary section of the backlight lamp tray. For this reason, in the correction process 2, in addition to the directional chromaticity conversion table used in the correction process 1, a depth coefficient for chromaticity conversion and a division coefficient within a variable range are provided, and these coefficients are stored in advance as register setting values. For example, in addition to the directional chromaticity conversion table, the following coefficients are defined.

Division factor: N = 2 to 10,
Depth coefficient: K [n] = 0.1 to 0.5, n is 0 to N−1

  A depth coefficient is provided for each division coefficient. That is, a boundary chromaticity conversion table corresponding to each division coefficient is provided. This table is stored in advance by providing storage means in the chromaticity correction unit 224. As shown in Table 6, when the division coefficient is set for each of the boundaries 1A, 1B, 2A, and 2B that are targets of the correction process 2 with respect to the register setting values in the directional chromaticity conversion table, the boundary chromaticity The depth coefficient of each section is determined with reference to the conversion table, and “depth coefficient * register setting value” (the symbol “*” means multiplication) is applied to each section divided by the division coefficient. The division coefficient of each section used in the correction process 2 may be set as a register value in advance, or may be set by the user before the correction process 2 is performed.

  For example, when the register setting values in the correction process 1 are R0, G0, and B10, and the sections of the boundaries 1A and 1B are set to the division coefficient 5 in the correction process 2, for example,

Division factor: N = 5
Depth coefficient: K [n] = 0.1 * n, n is 0 to N-1,
K [0] = 0.1 → (R0, G0, B1),
K [1] = 0.2 → (R0, G0, B2),
K [2] = 0.3 → (R0, G0, B3),
K [3] = 0.4 → (R0, G0, B4),
K [4] = 0.5 → (R0, G0, B5)

It is determined. The section division is based on equal division, but may be divided in a predetermined proportion. An example of how the depth coefficient is applied will be described with reference to FIG. 9. The section indicated by the boundary 2B is equally divided into five, and the line number indicated by the x-axis increases in this section of FIG. Since the amount to be corrected increases as the value is increased, K [4], K [3], K [2], K [1], and K [0] are divided into five equally divided sections, respectively. Apply a depth factor. Further, the section shown as boundary 2A is also equally divided into five, and in this section of FIG. 9, the amount to be corrected becomes smaller as the line number indicated by the x-axis increases, so that the equally divided five sections Are applied in the order of K [0], K [1], K [2], K [3], K [4].

  The correction process 1 and the correction process 2 are expressed as follows using the parameters defined as described above. FIG. 12 shows the chromaticity correction processing of FIG. 10 using the parameters defined as described above.

(1) Correction process 1
Yr _1/2/3 = Gr _1/2/3 * Xr _1/2/3 ,
Yg _1/2/3 = Gg _1/2/3 * Xg _1/2/3 ,
Yb _1/2/3 = Gb _1/2/3 * Xb _1/2/3 ,
Yr / g / b _1/2/3 is the output chromaticity (RGB component gradation), Xr / g / b _1/2/3 is the input chromaticity (RGB component gradation),
Gr _1/2/3 , Gg _1/2/3 , Gb _1/2/3 = chromaticity correction ratio corresponding to the register setting value (Table 4),
The correction target is applied to the upper, middle, and lower stages.

(2) Correction process 2
Yr _4/5/6/7 = K [n] * Gr _4/5/6/7 * Xr _4/5/6/7 , n is 0 to N-1,
Yg _4/5/6/7 = K [n] * Gg _4/5/6/7 * Xg _4/5/6/7 , n is 0 to N-1,
Yb _4/5/6/7 = K [n] * Gb _4/5/6/7 * Xb _4/5/6/7 , n is 0 to N-1,
Gr _4/5/6/7 , Gg _4/5/6/7 , Gb _4/5/6/7 = Chromaticity correction ratio corresponding to the register setting value (Table 4),
Yr / g / b _4/5/6/7 is output chromaticity (RGB component gradation), Xr / g / b _4/5/6/7 is input chromaticity (RGB component gradation),
N = division factor (number of divisions in the boundary section), K [n] = depth factor (n is 0 to N-1),
The correction target is applied to the boundary 1A, the boundary 1B, the boundary 2A, and the boundary 2B. The register setting value used in each section is the same as the register setting value used in the correction process 1 for the section including the section.

FIG. 13 shows a processing flow of chromaticity correction. The user measures the chromaticity of the surface of the liquid crystal panel, for example, at the center of each section for the upper (U), middle (M), and lower (D) shown in FIG. Steps S1, S2). Then, ΔWx and ΔWy are obtained by subtracting the chromaticities Wx and Wy of the reference tray from the chromaticities Wx and Wy of the adjustment tray, respectively, and input to the chromaticity correction unit 224 (step S3). The chromaticity correction unit 224 determines which value of −10 to +10 each corresponds to ΔWx and ΔWy in units of 0.0015, and sets the R, G, and B registers from the directional chromaticity conversion table (Table 5). A value is acquired (step S4). The processing of steps S5 to S7 is performed by the chromaticity correction unit 224 as described above.
Alternatively, the user may input the register setting value to the chromaticity correction unit 224 after obtaining the register setting value in step S4 without inputting ΔWx and ΔWy in step S3.
As described with reference to FIG. 1, the input to the chromaticity correction unit 224 is performed by OSD operation using the control terminal 100, or the register value of the chromaticity correction unit 224 is directly set through RS-232C or the like. To do.
Further, even if the user inputs the chromaticity Wx, Wy measured for each section and the reference chromaticity Wx, Wy to the chromaticity correction unit 224, the chromaticity correction unit 224 performs the processing of steps S1 to S4. Good. For example, the reference tray in step S1 is a tray in which the chromaticity difference from the reference chromaticity is less than 0.0005, and one of the other trays (if there are a plurality of trays, from step S8 if there are more than one). (Return to S2) is set as the adjustment tray in step S2. Then, in step S3, ΔWx and ΔWy are obtained by subtracting Wx and Wy of the reference tray from Wx and Wy of the adjustment tray, respectively, and in step S4, ΔWx and ΔWy are any values from −10 to +10 in units of 0.0015. R, G, B register setting values are obtained from the directional chromaticity conversion table (Table 5).

  As described above, in the liquid crystal display device, it is possible to display the screen without giving a sense of incongruity to the user by correcting the change in the color of the backlight light caused by the difference in the lamp characteristics of each light source for each lamp tray.

  This is effective in a liquid crystal display device with a backlight lamp drive type and a replaceable backlight.

It is a block diagram showing the structure of the liquid crystal display device by one Embodiment of this invention. Represents the current general process for chromaticity. The process of this embodiment regarding chromaticity is represented. The definition example of the effective display area and section of a liquid crystal display device is shown. This represents a case where a difference in chromaticity of the lamp appears. An outline of the correction process 1 is shown. An outline of the correction process 2 is shown. The processing section of the correction process 1 is represented. The processing section of the correction process 2 is represented. An overview of chromaticity correction processing is shown. It represents the directivity of white chromaticity. Represents chromaticity correction processing. A processing flow for chromaticity correction is shown. Represents the arrangement of the backlight lamp tray. This represents a case where a difference in chromaticity of the lamp appears. Represents the arrangement of the backlight lamp tray.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Control terminal 200 Control circuit 210 Video signal input part 220 Control basic part 221 Dimming control part 222 Control part 223 Color control part 224 Chromaticity correction part 230 Video signal output part 300 LCD module 310 Dimming circuit part 320 Power supply part 330 Back Light lamp unit basic unit 331 Backlight inverter unit 332 Backlight lamp unit 340 Video signal input unit 350 Control basic unit 351 Basic unit 352 Voltage control unit 353 Gradation control unit 360 Drive circuit basic unit 361, 362 Source drive circuit unit 363, 364 Gate drive circuit section

Claims (3)

With respect to the chromaticity measured on the surface of the liquid crystal panel for each divided area obtained by dividing the display area of the liquid crystal panel according to the arrangement of a plurality of backlight lamps, the chromaticity difference between adjacent divided areas is less than a predetermined value. Storage means for preliminarily storing adjustment parameters set so as to decrease
A first correction unit that adjusts the gradation of the RGB component of the video signal corresponding to the specified divided area of the divided areas based on the adjustment parameter ;
Look including the border between the first divisional area and a second partitioned area adjacent to the divided area where the video signal is adjusted, the first region and the second is a part of the first segment area when adjusting the gradation of the RGB components of the corresponding video signal to a region obtained by combining the second region which is a part of the synthesis regions of partitioned regions, over the previous SL first region and the second region, the second Second correction means for performing adjustment based on the adjustment parameter that is different between one area and the second area;
A video signal correction apparatus comprising: With respect to the chromaticity measured on the surface of the liquid crystal panel for each divided area obtained by dividing the display area of the liquid crystal panel according to the arrangement of a plurality of backlight lamps, the chromaticity difference between adjacent divided areas is less than a predetermined value. Obtaining the adjustment parameter from the storage means for storing in advance the adjustment parameter set to be reduced to
A first step of adjusting the gradation of the RGB components of the video signal corresponding to the specified divided area of the divided areas based on the adjustment parameter ;
Look including the border between the first divisional area and a second partitioned area adjacent to the divided area where the video signal is adjusted, the first region and the second is a part of the first segment area when adjusting the gradation of the RGB components of the corresponding video signal to a region obtained by combining the second region which is a part of the synthesis regions of partitioned regions, over the previous SL first region and the second region, the second A second step of performing the adjustment based on the adjustment parameter that is different between the first region and the second region;
A video signal correction method comprising: In the computer of the video signal correction device,
With respect to the chromaticity measured on the surface of the liquid crystal panel for each divided area obtained by dividing the display area of the liquid crystal panel according to the arrangement of a plurality of backlight lamps, the chromaticity difference between adjacent divided areas is less than a predetermined value. Obtaining the adjustment parameter from storage means for preliminarily storing the adjustment parameter set so as to be reduced;
A first step of adjusting , based on the adjustment parameter, a gradation of an RGB component of a video signal corresponding to a specified divided area of the divided areas;
Look including the border between the first divisional area and a second partitioned area adjacent to the divided area where the video signal is adjusted, the first region and the second is a part of the first segment area when adjusting the gradation of the RGB components of the corresponding video signal to a region obtained by combining the second region which is a part of the synthesis regions of partitioned regions, over the previous SL first region and the second region, the second A second step of performing an adjustment based on the adjustment parameter that is different between the first region and the second region;
A program that executes

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