JP7045807B2 - Method, color adjuster, program and display system - Google Patents

Description

The present invention relates to a display driver setting method, a color adjusting device, a program, and a display system, and more particularly to a method and a device for setting a display driver configured to perform a color adjusting process and a color addition process.

One of the most typical image data formats is the RGB format. The image data in the RGB format has a format for describing the gradation values that specify the gradations of the primary colors R, the primary colors G, and the primary colors B for each pixel of the image. Most typically, the gradation values of the primary colors R, the primary colors G, and the primary colors B are each described by 8 bits. In the following, the image data in RGB format may be simply referred to as RGB data.

On the other hand, in recent display panels (for example, liquid crystal display panels and OLED (organic light emitting diode) display panels), in order to improve image quality, each pixel displays an R sub-pixel displaying a primary color R and a primary color G. In addition to the G sub-pixels that display the primary colors B and the B sub-pixels that display the primary colors B, additional sub-pixels that display additional colors other than the primary colors R, G, and B may be included. As the additional color, for example, yellow Y, light blue C, and white W may be used. In the following, the additional color is represented by the symbol “F”, and the sub-pixel displaying the color F may be referred to as an F sub-pixel.

When an image is displayed on a display panel in which each pixel has an F sub-pixel in addition to an R sub-pixel, a G sub-pixel, and a B sub-pixel according to the RGB data, color addition processing may be performed on the RGB data. be. Since the gradation value of the F sub-pixel is not described in the RGB data, when the image is displayed on the display panel provided with the F sub-pixel according to the RGB data, the R sub-pixel, the G sub-pixel, and the B are displayed from the RGB data. It is necessary to perform digital image processing to generate image data that describes the gradation values of the sub-pixel and the F sub-pixel. Such digital image processing is the color addition processing referred to in the present specification. Properly designing the color addition process is useful for improving the image quality of the display panel. In the following, image data in a format that describes the gradation values of the R sub-pixel, G sub-pixel, B sub-pixel, and F sub-pixel of each pixel may be referred to as FRGB data. In the present specification, the color addition process refers to an image process for generating FRGB data from RGB data.

Another technique that contributes to improving the image quality of the display panel is color correction processing. The color correction process is a digital image process performed on image data for color adjustment of the display panel (adjustment of the color displayed on the display panel). The color correction process is performed, for example, for color space management to match the color gamut used in the generation of image data with the color gamut of the image displayed on the display panel. It is intended in the generation of image data that the color gamut used in the generation of image data (for example, the color gamut specified in the sRGB standard or the Adobe RGB standard) and the color gamut of the image displayed on the display panel are different. A color different from the original color will be displayed on the display panel. This is not preferable from the viewpoint of improving the image quality. The color gamut adjustment is performed to display the image on the display panel in the color intended in the generation of the image data.

One of the problems found by the inventor is that performing color addition processing and color correction processing (for example, color gamut adjustment) separately can deteriorate image quality and circuit characteristics.

FIG. 1 shows an example of image processing performed when an image is displayed on a display panel in which each pixel includes an R sub-pixel, a G sub-pixel, a B sub-pixel, and an F sub-pixel according to RGB data. .. In the image processing shown in FIG. 1, FRGB data is generated by performing color addition processing on RGB data, and color-adjusted FRGB data is generated by performing color gamut adjustment on the FRGB data. , Gamma-corrected FRGB data is generated by performing gamma correction on the color-adjusted FRGB data. The display panel is driven according to the gamma-corrected FRGB data.

The image processing of FIG. 1 requires a color gamut adjustment technique corresponding to FRGB data, but a color gamut adjustment technique corresponding to FRGB data is not known. Further, when performing the image processing of FIG. 1, since the image data in which the gradation values of four colors are described is handled in the color gamut adjustment, the circuit scale and the circuit scale and the case of performing the color gamut adjustment for the RGB data Power consumption increases by 33% by simple calculation.

FIG. 2 shows another example of image processing performed when an image is displayed on a display panel in which each pixel includes an R sub-pixel, a G sub-pixel, a B sub-pixel, and an F sub-pixel according to RGB data. ing. In the image processing shown in FIG. 2, color gamut adjustment is performed on RGB data to generate color-adjusted RGB data, and color addition processing is performed on the color-adjusted RGB data to perform FRGB data. Is generated, and the FRGB data after gamma correction is generated by performing gamma correction on the FRGB data. The display panel is driven according to the gamma-corrected FRGB data. In the image processing of FIG. 2, a conventionally known color gamut adjustment technique can be applied, and an increase in circuit scale and power consumption can be suppressed.

One problem in the image processing of FIG. 2 is that the color may change in the color addition processing. When the additional color F is white W, the color addition process most typically performed is to set the minimum value among the gradation values of the R sub-pixel, the G sub-pixel, and the B sub-pixel described in the RGB data. The gradation value of the R sub-pixel, G sub-pixel, and B sub-pixel of the image data after the color addition processing is determined as the gradation value of white W, and the R sub-pixel, G sub-pixel, and B of the original RGB data are set. This is a process of calculating by subtracting the minimum value from the gradation value of the sub-pixel. However, in such a color addition process, the color changes. When the color changes in the color addition process, the result of the color adjustment (for example, color gamut adjustment) that should be realized by the color correction process is lost, and the image quality deteriorates.

Therefore, there is a technical need to provide a technique for realizing a desired color adjustment (for example, a desired color gamut adjustment) even if a color addition process that changes the color is performed. exist.

The following techniques are known in relation to color gamut adjustment and color addition processing.

Japanese Unexamined Patent Publication No. 2008-40305 discloses a technique for processing a hue by sequentially performing RGB-XYZ conversion, XYZ-LMS conversion, color correction, LMS-XYZ conversion, and XYZ-RGB conversion.

Japanese Unexamined Patent Publication No. 2008-141723 discloses a technique for realizing a color gamut specified in the Adobe RGB standard by performing YCbCr-RGB conversion and RGB-RGB conversion on YCbCr data.

Japanese Unexamined Patent Publication No. 2002-116750 discloses a technique for adjusting a color gamut by matrix conversion.

In International Publication No. 2012/137819, regarding the color addition process, when converting RGB data to RGBX data for each pixel, the brightness of white (W) is set to the white (W) of a pixel included in a predetermined area including the pixel. ) Discloses a technique for determining the brightness to be substantially the same.

Japanese Unexamined Patent Publication No. 2006-133711 discloses a color addition process for calculating an RGBW signal from an RGB input signal. The color addition process disclosed in this publication includes a step of determining the minimum value of the RGB input signal, a step of subtracting the minimum value from the RGB input signal, and an RGBW signal corresponding to the case where the RGB input signal is the minimum value. The RGBW signal to be finally output is obtained by adding the corresponding signal of the RGB signal obtained in the step of subtracting the minimum value from the RGB input signal to the calculated RGBW signal. It has the steps you want.

Japanese Patent Application Laid-Open No. 2008-131349 describes the calculation of the outermost shell surface based on device data, the primary color enlargement processing for expanding the RGB color reduction vector in the saturation direction, the RGBW-XYZ-RGB conversion processing, the RGBW separation processing, and the W value adjustment. It discloses a color addition process in which the processes are sequentially performed.

Japanese Unexamined Patent Publication No. 2008-40305 Japanese Unexamined Patent Publication No. 2008-141723 Japanese Unexamined Patent Publication No. 2002-116750 International Publication No. 2012/137819 Japanese Unexamined Patent Publication No. 2006-133711 Japanese Unexamined Patent Publication No. 2008-131349

Therefore, one of the objects of the present invention is to provide a technique for realizing a desired color adjustment (for example, a desired color gamut adjustment) even if a color addition process that changes the color is performed. There is something in it. Other objects and novel features of the invention will be appreciated by those of skill in the art from the disclosure below.

From one viewpoint of the present invention, a plurality of pixels are included, and each of the plurality of pixels includes an R subpixel that displays the primary color R, a G subpixel that displays the primary color G, and a B subpixel that displays the primary color B. , A display driver corresponding to a display panel including an F sub-pixel that displays additional colors other than the primary colors R, primary color G, and primary color B, and color correction processing for RGB data according to color correction parameters. Is performed to generate RGB data after color correction, and color addition processing is performed on the RGB data after color correction to specify the F gradation value and R to specify the gradation of the F sub-pixel. Generates FRGB data including the G gradation value that specifies the gradation value and the gradation of the G sub-pixel and the B gradation value that specifies the gradation of the B sub-pixel, and drives the display panel according to the FRGB data. A setting method for setting color correction parameters is provided for a display driver configured as described above. The setting method is
The first displayed on the display panel when the R sub-pixel, G sub-pixel, and B sub-pixel are driven by the drive signal corresponding to the minimum gradation value, and the F sub-pixel is driven by the drive signal corresponding to the maximum gradation value. A step of acquiring first color coordinate data indicating color coordinates of one display color in a predetermined color space, and
Steps to determine the color correction parameters to be evaluated and
A step of performing color correction processing on the RGB data to be calibrated based on the color correction parameters to be evaluated to generate RGB data after color correction to be evaluated.
A step to generate evaluation target FRGB data by performing color addition processing on the evaluation target color corrected RGB data, and
A step of determining whether or not the evaluation target color correction parameter is appropriate based on the evaluation target FRGB data and the first color coordinate data, and
When it is determined that the evaluation target color correction parameter is appropriate, it includes a step of determining the evaluation target color correction parameter as a color correction parameter to be set in the display driver.

Another aspect of the present invention provides a color adjusting device for setting color correction parameters to the display driver described above. The color adjusting device includes an arithmetic unit and an interface. The arithmetic unit drives the R subpixel, the G subpixel, and the B subpixel with a drive signal corresponding to the minimum gradation value, and displays the F subpixel on the display panel when driven by the drive signal corresponding to the maximum gradation value. Color coordinate data indicating the color coordinates of the displayed display color in a predetermined color space is acquired, the evaluation target color correction parameter is determined, and the color correction process is performed on the calibration target RGB data based on the evaluation target color correction parameter. To generate RGB data after color correction for evaluation, add color to the RGB data after color correction for evaluation to generate FRGB data for evaluation, and based on the FRGB data for evaluation and color coordinate data. It is configured to determine whether the evaluation target color correction parameter is appropriate, and if it is determined that the evaluation target color correction parameter is appropriate, the evaluation target color correction parameter is determined as the color correction parameter to be set in the display driver. Has been done. The interface sends the color correction parameters to the display driver.

In still another aspect of the invention, a program for setting color correction parameters to the display driver is provided. The program is applied to the arithmetic unit in the following steps:
The display displayed on the display panel when the R sub-pixel, G sub-pixel, and B sub-pixel are driven by the drive signal corresponding to the minimum gradation value, and the F sub-pixel is driven by the drive signal corresponding to the maximum gradation value. A step of acquiring color coordinate data indicating the color coordinates of a color in a predetermined color space,
Steps to determine the color correction parameters to be evaluated,
A step of performing color correction processing on the RGB data to be calibrated based on the color correction parameters to be evaluated to generate RGB data after color correction to be evaluated.
A step of generating evaluation target FRGB data by performing color addition processing on the evaluation target color corrected RGB data.
A step of determining whether or not the evaluation target color correction parameter is appropriate based on the evaluation target FRGB data and the color coordinate data, and
When it is determined that the evaluation target color correction parameter is appropriate, the step of determining the evaluation target color correction parameter as the color correction parameter to be set in the display driver is executed.

According to the present invention, a desired color adjustment (for example, a desired color gamut adjustment) can be realized even if a color addition process that changes the color is performed.

An example of image processing performed when an image is displayed on a display panel in which each pixel includes an R sub-pixel, a G sub-pixel, a B sub-pixel, and an F sub-pixel according to RGB data is shown. Another example of image processing performed when an image is displayed on a display panel in which each pixel includes an R sub-pixel, a G sub-pixel, a B sub-pixel, and an F sub-pixel according to RGB data is shown. It is a block diagram which shows the structure of the display device in one Embodiment. It is a figure which shows an example of the structure of each pixel of a display panel. It is a block diagram which shows the structure of the display driver in one Embodiment. It is a block diagram which shows the structure of the color adjustment apparatus in one Embodiment. It is a block diagram which shows the structure of the arithmetic unit of the color adjustment apparatus in one Embodiment. It is a flowchart which shows the procedure of calculation of a color adjustment parameter in one Embodiment. It is a chromaticity diagram which shows the luminance coordinate data of the primary color R, the primary color G, the primary color B and the color F of the maximum gradation value in the xyY color system, and the luminance coordinate data of a white point (WP). It is a flowchart which shows the procedure of calculation of a color adjustment parameter in another embodiment. It is a block diagram schematically showing the structure of the luminance coordinate measuring apparatus and the display apparatus in another embodiment. FIG. 3 is a block diagram schematically showing a configuration of a display system according to an embodiment of FIG. It is a block diagram which shows the actual operation of the display system of FIG. It is a block diagram schematically showing the structure of the luminance coordinate measuring apparatus and the display apparatus in still another embodiment. FIG. 3 is a block diagram schematically showing a configuration of a display system according to an embodiment of FIG. It is a block diagram schematically showing the structure of the luminance coordinate measuring apparatus and the display apparatus in still another embodiment. FIG. 3 is a block diagram schematically showing a configuration of a display system according to the embodiment of FIG.

FIG. 3 is a block diagram showing a configuration of a display device 100 to which the display driver setting method of the present invention is applied in one embodiment.

In this embodiment, the display device 100 includes a display panel 1 and a display driver 2. The display device 100 is configured to receive image data from the host 3 and display an image corresponding to the received image data on the display panel 1. In the present embodiment, the image data supplied from the host 3 to the display driver 2 has an RGB format, and describes gradation values that specify the gradations of the primary colors R, primary colors G, and primary colors B for each pixel. ing. In one embodiment, the gradations of the primary colors R, the primary colors G, and the primary colors B may be specified by 8-bit gradation values.

The display panel 1 includes an active region 4 and a gate driver circuit 5. A plurality of gate lines 6, a plurality of source lines 7, and a plurality of pixel circuits 8 are arranged in the active region 4. The pixel circuits 8 are arranged in a matrix, and each pixel circuit 8 is provided at a position where the corresponding gate line 6 and the source line 7 intersect. In the following, the direction in which the gate line 6 extends may be referred to as a "horizontal direction".

When the display panel 1 is configured as a liquid crystal display panel, in one embodiment, each pixel circuit 8 may include a selection transistor, a pixel electrode, and a holding capacitance (none of which is shown). In this case, a driving voltage is applied between the pixel electrode of each pixel circuit 8 and the common electrode (not shown) of the display panel 1, and the orientation of the liquid crystal existing between the pixel electrode and the common electrode is the pixel electrode and the common electrode. It is controlled by the electric field generated during.

When the display panel 1 is configured as an OLED (organic light emitting diode) display panel, the pixel circuit 8 has an OLED element, a drive circuit for driving the OLED element, and a holding capacity for storing the drive electrode. It may be included (neither is shown). In this case, a current corresponding to the voltage held in the holding capacity is supplied to the OLED element to drive the OLED element.

FIG. 4 is a diagram showing an example of the configuration of each pixel 10 of the display panel 1. In the present embodiment, each pixel 10 includes a pixel circuit 8 that displays a primary color R (red), a primary color G (green), and a primary color B (blue), and a pixel circuit 8 that displays an additional color F. There is. As the additional color F, for example, yellow Y, light blue C, and white W may be used. The pixel circuit 8 that displays the primary color R is used as the R sub-pixel, and the pixel circuit 8 that displays the primary color G is used as the G sub-pixel. Further, the pixel circuit 8 that displays the primary color B is used as the B sub-pixel, and the pixel circuit 8 that displays the color F is used as the F sub-pixel. In the following, the pixel circuit 8 for displaying the primary color R, the primary color G, the primary color B, and the color F may be described as R sub-pixel 8R, G sub-pixel 8G, B sub-pixel 8B, and F sub-pixel 8F, respectively. In the present embodiment, the R sub-pixel 8R, the G sub-pixel 8G, the B sub-pixel 8B, and the F sub-pixel 8F included in each pixel 10 are arranged side by side in the horizontal direction and are connected to the same gate line 6. To.

In FIG. 4, the F sub-pixel 8F, the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B are arranged in this order in each pixel 10, that is, the F sub-pixel 8F is located at the left end of each pixel 10. However, the arrangement of the F sub-pixel 8F, the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B is not limited to the arrangement shown in FIG. For example, the order in which the F sub-pixel 8F, the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B are arranged can be appropriately changed.

Returning to FIG. 3, the gate driver circuit 5 drives the gate line 6 in response to the control signal received from the display driver 2. In this embodiment, a pair of gate driver circuits 5 are provided on the left and right sides of the active region 4. The gate driver circuit 5 is integrated in the display panel 1 by SoG (System on Glass) technology.

The display driver 2 is a semiconductor integrated circuit that operates as described below. First, the display driver 2 has a source output connected to the source line 7 of the display panel 1, and drives each pixel circuit 8 of the display panel 1 according to the image data received from the host 3. Second, the display driver 2 supplies a gate control signal to the gate driver circuit 5 according to the control data received from the host 3, thereby controlling the gate driver circuit 5.

FIG. 5 is a block diagram schematically showing the configuration of the display driver 2 in the present embodiment. The display driver 2 includes an interface circuit 21, an image processing IP core 22, a source driver circuit 23, a panel interface circuit 24, a register circuit 25, a non-volatile memory 26, and a timing controller 27.

The interface circuit 21 receives image data in RGB format from the host 3 and transfers the received image data to the image processing IP core 22. The interface circuit 21 further receives control data from the host 3 and stores commands and control parameters included in the control data in the register circuit 25.

The image processing IP core 22 operates as an image processing circuit that performs desired image processing on the image data in RGB format received from the interface circuit 21 and generates the processed image data. The processed image data has a format for describing gradation values that specify the gradations of the R sub-pixel 8R, the G sub-pixel 8G, the B sub-pixel 8B, and the F sub-pixel 8F.

The image processing performed in the image processing IP core 22 may include image processing other than the color correction processing and the color addition processing. In this case, the circuit for performing the image processing is in the image processing IP core 22. May be added.

The source driver circuit 23 operates as a drive circuit unit that drives the source line 7 of the display panel 1 in response to the processed image data received from the image processing IP core 22.

The panel interface circuit 24 generates a gate control signal according to the control data received from the host 3, and supplies the generated gate control signal to the gate driver circuit 5.

The register circuit 25 holds commands and control parameters used to control the display driver 2. The commands and control parameters included in the control data received from the host 3 are stored in the register circuit 25.

The non-volatile memory 26 non-volatilely holds the control parameters used for controlling the display driver 2. When the display driver 2 is started, the control parameters stored in the non-volatile memory 26 are read out and stored in the register circuit 25, and the control parameters stored in the register circuit 25 are used for controlling the display driver 2.

The timing controller 27 determines the timing of the circuit group (for example, the image processing IP core 22, the source driver circuit 23, and the panel interface circuit 24) included in the display driver 2 according to the commands and control parameters stored in the register circuit 25. Take control.

In the present embodiment, the image processing IP core 22 is configured to perform color correction processing and color addition processing. More specifically, the image processing IP core 22 includes a color correction circuit 28 and a color addition processing circuit 29.

The color correction circuit 28 performs color correction processing on the RGB format image data received from the interface circuit 21, and generates RGB data after color correction. The color correction process in the color correction circuit 28 is performed according to the color correction parameters supplied from the register circuit 25. The color correction parameter specifies the mode of the color correction process in the color correction circuit 28 (for example, the degree to which each primary color is emphasized, the degree to which the saturation is emphasized, etc.).

The color correction parameters are non-volatilely stored in the color correction parameter storage area 31 of the non-volatile memory 26. When the display driver 2 is started, the color correction parameters stored in the color correction parameter storage area 31 are read out and stored in the register circuit 25, and the color correction parameters stored in the register circuit 25 are supplied to the color correction circuit 28. Will be done. The color correction circuit 28 performs color correction processing according to the color correction parameters received from the register circuit 25.

The color addition processing circuit 29 performs color addition processing on the color-corrected RGB data received from the color correction circuit 28 to generate FRGB data. As described above, the FRGB data is image data in a format that describes the gradation values of the R sub-pixel, the G sub-pixel, the B sub-pixel, and the F sub-pixel of each pixel. The generated FRGB data or image data obtained by performing desired image processing on the FRGB data is supplied to the source driver circuit 23 as post-processed image data.

In order to realize the desired color adjustment (for example, the desired color gamut adjustment), it is desired to optimally calculate the color correction parameters used in the color correction processing. According to the inventor's study, one of the considerations in calculating the color correction parameters is that color changes can occur in the color addition processing performed after the color correction processing. If the color correction parameters are calculated in consideration of the color change in the color addition process, the image data with the desired color adjustment can be finally obtained. In the following, a technique for calculating an appropriate color correction parameter in consideration of a color change in the color addition process and setting it in the display driver 2 (that is, writing it in the color correction parameter storage area 31) is presented.

In the present embodiment, in the calculation of the color correction parameter, the color coordinate data indicating the color coordinates in the predetermined color space of the color F of the maximum gradation value is acquired, and the acquired color coordinate data is used for the calculation of the color correction parameter. Be done. Strictly speaking, the color coordinate data of the color F having the maximum gradation value is that the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B of the display panel 1 are driven by a drive signal corresponding to the minimum gradation value. , F This is data indicating the color coordinates of the display color displayed on the display panel 1 in a predetermined color space when the sub-pixel 8F is driven by the drive signal corresponding to the maximum gradation value.

In the present embodiment, the color coordinate data of the color F of the acquired maximum gradation value is used to evaluate the appropriateness of the color correction parameter. The evaluation of the appropriateness of the color correction parameters is roughly performed as follows.

The RGB data to be calibrated (Ri, Gi, Bi) and the target RGB data (Rt, Gt, Bt) associated with the calibration target RGB data (Ri, Gi, Bi) are prepared in advance. The RGB data to be calibrated (Ri, Gi, Bi) is the RGB data to be determined whether the color correction parameter is appropriate. The target RGB data (Rt, Gt, Bt) represents the target color to be realized when the color correction processing and the color addition processing are performed on the RGB data (Ri, Gi, Bi) to be calibrated in RGB format. It is data and is used to determine whether or not the color correction parameter is appropriate for the corresponding RGB data (Ri, Gi, Bi) to be calibrated.

Color correction processing is performed on the RGB data (Ri, Gi, Bi) to be calibrated using the color correction parameters for which appropriateness should be evaluated to generate color-corrected RGB data, and further, color-corrected RGB data. Color addition processing is performed on the data, and FRGB data (Fa, Ra, Ga, Ba) is generated. Here, Fa, Ra, Ga, and Ba are gradation values of the F sub-pixel 8F, the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B, respectively. The RGB luminance component data (Rr, Gr, Br) representing the colors displayed on the display panel 1 when the display panel 1 is driven according to the FRGB data in RGB format is the color F of the maximum gradation value. Calculated using coordinate data. The RGB luminance component data (Rr, Gr, Br) indicates the components of the primary colors R, primary colors G, and primary colors B displayed on the display panel 1 when the display panel 1 is driven according to the FRGB data. Become. Since the color coordinate data of the color F having the maximum gradation value includes the color information displayed by the F sub-pixel 8F, the RGB luminance component data (Rr, Gr, Br) can be calculated from the FRGB data.

The appropriateness of the color correction parameter is determined based on the result (that is, similarity) of comparison between the RGB luminance component data (Rr, Gr, Br) and the target RGB data (Rt, Gt, Bt). When the RGB luminance component data (Rr, Gr, Br) matches the target RGB data (Rt, Gt, Bt) or is close to the target RGB data (Rt, Gt, Bt), the color correction parameter is appropriate. Judged. When the RGB luminance component data (Rr, Gr, Br) is significantly different from the target RGB data (Rt, Gt, Bt), it is determined that the color correction parameter is not appropriate, and the color correction parameter is adjusted. When the color correction parameters are adjusted, the same evaluation is performed on the adjusted color correction parameters. Such a procedure is repeated until it is determined that the color correction parameters are appropriate. The color correction parameters determined to be appropriate are stored in the non-volatile memory 26 of the display driver 2.

In one embodiment, the color coordinate data of the color F having the maximum gradation value may be acquired by actually performing the measurement on the display panel 1. In this case, as the color coordinate data of the color F having the maximum gradation value, the F sub-pixel 8F is driven by the drive signal corresponding to the maximum gradation value for all the pixels 10 of the display panel 1, and the other sub-pixels (R) are driven. Sub-pixel 8R, G sub-pixel 8G, B sub-pixel 8B) is a color indicating the color coordinates of the display color displayed on the display panel 1 in a state of being driven by the drive signal corresponding to the minimum gradation value in a predetermined color space. The coordinate data is measured by a measuring device (eg, a brightness meter). As the color space, for example, an xyY color system can be used. In this case, the color coordinate data of the color F may be acquired as the luminance coordinate data indicating the stimulus value (luminance) Y and the chromaticity coordinates (x, y) in the xyY color system.

In another embodiment, from the design data of the display panel 1, for example, the data showing the characteristics of the filter provided on the display panel 1, the color coordinate data of the color F having the maximum gradation value, that is, the R sub-sub of the display panel 1. Displayed on the display panel 1 when the pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B are driven by the drive signal corresponding to the minimum gradation value, and the F sub-pixel 8F is driven by the drive signal corresponding to the maximum gradation value. The color coordinate data (brightness coordinate data) of the display color to be displayed may be calculated.

The number of colors F added to the primary colors R, G, and B is not limited to one. When the number of additional colors F is 2 or more, the color coordinate data of the color F having the maximum gradation value is acquired for each of the additional colors F, and the acquired color coordinate data determines the appropriateness of the color correction parameter. Used for evaluation.

Hereinafter, the calculation of the color correction parameter in the present embodiment will be described in detail. FIG. 6 is a block diagram showing a configuration of a color adjusting device 200 used for optimally calculating a color correction parameter to be set in the display driver 2 in the present embodiment. The color adjusting device 200 includes a luminance meter 11 and an arithmetic unit 12.

The luminance meter 11 measures the color coordinates of the display color displayed on the display panel 1 in a predetermined color space, generates color coordinate data indicating the color coordinates, and supplies the color coordinate data to the arithmetic unit 12. In the present embodiment, the luminance meter 11 measures the stimulus value (luminance) Y and the chromaticity coordinate (x, y) in the xyY color system, and indicates the measured stimulus value Y and the chromaticity coordinate (x, y). The luminance coordinate data is supplied to the arithmetic unit 12 as the above color coordinate data. As will be described later, in the present embodiment, the stimulus value Y and the chromaticity coordinates (x, y) when the primary colors R, the primary colors G, the primary colors B and the color F are displayed on the display panel 1 at the maximum gradation value are shown. The luminance coordinate data and the luminance coordinate data indicating the stimulus value Y and the chromaticity coordinates (x, y) of the white point (WP) of the display panel 1 are acquired by the luminance meter 11, and the acquired luminance coordinate data is the arithmetic unit. It is supplied to 12.

The arithmetic unit 12 calculates the color correction parameter to be set in the display driver 2 from the color coordinate data (in this embodiment, the luminance coordinate data) received from the luminance meter 11. FIG. 7 is a block diagram showing an example of the configuration of the arithmetic unit 12.

In the present embodiment, the arithmetic unit 12 is configured as a computer in which the color adjustment software 13 is installed, and includes an interface 14, a storage device 15, a processor 16, and an interface 17. The interface 14 receives color coordinate data (in this embodiment, luminance coordinate data) from the luminance meter 11.

The storage device 15 stores color adjustment software 13 for calculating color correction parameters. The calculation of the color correction parameter is performed by the processor 16 executing the color adjustment software 13. In addition to calculating the color correction parameters, the color adjustment software 13 also performs a process of generating image data and control data to be supplied to the display driver 2 in the process of calculating the color correction parameters. The storage device 15 is also used as a work area for calculating color correction parameters. The storage device 15 stores various data (for example, the above-mentioned luminance coordinate data) used in the process of calculating the color correction parameter or generated in the process of calculation. The interface 17 transmits the calculated color correction parameter to the display driver 2, and further transmits the image data and the control data to be supplied to the display driver 2 in the process of calculating the color correction parameter to the display driver 2.

The storage device 15 of the arithmetic unit 12 stores RGB data to be calibrated (Ri, Gi, Bi) and target RGB data (Rt, Gt, Bt) associated with the RGB data (Ri, Gi, Bi). The RGB data to be calibrated (Ri, Gi, Bi) is the RGB data to be determined whether the color correction parameter is appropriate. The target RGB data (Rt, Gt, Bt) is data indicating the target color to be realized when the color correction processing and the color addition processing are performed on the RGB data (Ri, Gi, Bi) to be calibrated. , Used to determine whether the color correction parameters are appropriate for the corresponding calibrated RGB data (Ri, Gi, Bi). The number of pairs of the RGB data (Ri, Gi, Bi) to be calibrated and the target RGB data (Rt, Gt, Bt) stored in the storage device 15 may be one or a plurality.

Subsequently, a procedure for calculating the color correction parameter using the color adjusting device 200 shown in FIG. 6 will be described. FIG. 8 is a flowchart showing a procedure for calculating the color correction parameter in the present embodiment. Each step shown in FIG. 8 is executed by the processor 16 of the arithmetic unit 12 executing the color adjustment software 13.

First, the luminance coordinate data of the primary color R, the primary color G, the primary color B and the color F of the maximum gradation value, and the luminance coordinate data of the white point (WP) are acquired (step S01).

In the present embodiment, the brightness coordinate data of the primary color R of the maximum gradation value drives the R subpixel 8R of the display panel 1 with a drive signal corresponding to the maximum gradation value, and other subpixels (F subpixel 8F, The stimulus value Y and chromaticity coordinates (x) in the xyY color system of the display color displayed on the display panel 1 in a state where the G sub-pixel 8G and the B sub-pixel 8B) are driven by the drive signal corresponding to the minimum gradation value. , Y) are acquired as data including. In the following, the luminance coordinate data of the primary color R of the maximum gradation value may be described as (RY, Rx, Ry). Here, RY is the stimulus value Y of the primary color R, and Rx and Ry are the chromaticity coordinates x and y of the primary color R, respectively.

In one embodiment, in the acquisition of the brightness coordinate data of the primary color R of the maximum gradation value, the color adjustment software 13 applies the image processing IP core 22 to the source driver circuit 23 as post-processing image data for all the pixels 10. Control to instruct to supply image data in which the gradation value of the R sub-pixel 8R is the maximum gradation value and the gradation value of the F sub-pixel 8F, the G sub-pixel 8G, and the B sub-pixel 8B is the minimum gradation value. Send the data to the display driver 2. While the source driver circuit 23 drives the display panel 1 according to the processed image data generated in this way, the color adjustment software 13 controls the luminance meter 11 and displays it on the display panel 1. Measure the luminance coordinate data of the display color. The luminance coordinate data acquired in this way is the luminance coordinate data of the primary color R having the maximum gradation value.

Similarly, the brightness coordinate data of the primary color G of the maximum gradation value drives the G subpixel 8G of the display panel 1 with the drive signal corresponding to the maximum gradation value, and other subpixels (F subpixel 8F, R subpixel). Stimulation value Y and chromaticity coordinates (x, y) in the xyY color system of the display color displayed on the display panel 1 in a state where the pixel 8R, B sub-pixel 8B) is driven by the drive signal corresponding to the minimum gradation value. ) Is included in the data. In the following, the luminance coordinate data of the primary color G having the maximum gradation value may be described as (GY, Gx, Gy). Here, GY is the stimulus value Y of the primary color G, and Gx and Gy are the chromaticity coordinates x and y of the primary color G, respectively. In the brightness coordinate data of the primary color G of the maximum gradation value, the gradation value of the G sub-pixel 8G is the maximum gradation value for all the pixels 10, and the floor of the F sub-pixel 8F, the R sub-pixel 8R, and the B sub-pixel 8B. It is measured in the same manner as the brightness coordinate data of the primary color R of the maximum gradation value, except that the image data whose adjustment value is the minimum gradation value is supplied to the source driver circuit 23.

Further, the brightness coordinate data of the primary color B of the maximum gradation value drives the B sub-pixel 8B of the display panel 1 with the drive signal corresponding to the maximum gradation value, and other sub-pixels (F sub-pixel 8F, R sub-pixel). Stimulation value Y and chromaticity coordinates (x, y) in the xyY color system of the display color displayed on the display panel 1 in a state where the 8R, G subpixel 8G) is driven by the drive signal corresponding to the minimum gradation value. Is acquired as data containing. In the following, the luminance coordinate data of the primary color B having the maximum gradation value may be described as (BY, Bx, By). Here, BY is the stimulus value Y of the primary color B, and Bx and By are the chromaticity coordinates x and y of the primary color B, respectively. In the brightness coordinate data of the primary color B of the maximum gradation value, the gradation value of the B sub-pixel 8B is the maximum gradation value for all the pixels 10, and the floor of the F sub-pixel 8F, the R sub-pixel 8R, and the G sub-pixel 8G. The measurement is performed in the same manner as the brightness coordinate data of the primary color R and the primary color G of the maximum gradation value, except that the image data whose adjustment value is the minimum gradation value is supplied to the source driver circuit 23.

Further, the brightness coordinate data of the color F having the maximum gradation value drives the F sub-pixel 8F of the display panel 1 with the drive signal corresponding to the maximum gradation value, and other sub-pixels (R sub-pixel 8R, G sub-pixel). Stimulation value Y and chromaticity coordinates (x, y) in the xyY color system of the display color displayed on the display panel 1 in a state where 8G, B sub-pixel 8B) is driven by a drive signal corresponding to the minimum gradation value. Is acquired as data containing. In the following, the luminance coordinate data of the color F may be described as (FY, Fx, Fy). Here, FY is the stimulus value Y of the color F, and Fx and Fy are the chromaticity coordinates x and y of the color F, respectively. In the brightness coordinate data of the color F of the maximum gradation value, the gradation value of the F sub-pixel 8F is the maximum gradation value for all the pixels 10, and the floor of the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B. The measurement is performed in the same manner as the brightness coordinate data of the primary colors R, the primary colors G, and the primary colors B of the maximum gradation values, except that the image data whose adjustment value is the minimum gradation value is supplied to the source driver circuit 23.

On the other hand, the brightness coordinate data of the white point (WP) drives the R sub-pixel 8R, G sub-pixel 8G, and B sub-pixel 8B of the display panel 1 with a drive signal corresponding to the maximum gradation value, and drives the F sub-pixel 8F. It is measured as data including the stimulus value Y and the chromaticity coordinates (x, y) in the xyY color system of the display color displayed on the display panel 1 in a state of being driven by the drive signal corresponding to the minimum gradation value. In the following, the luminance coordinate data of the white point may be described as (WY, Wx, Wy). Here, WY is the stimulus value Y of the white point, and Wx and Wy are the chromaticity coordinates x and y of the white point, respectively.

In the acquisition of the brightness coordinate data of the white point (WP), the color adjustment software 13 uses the R subpixels for all the pixels 10 as the processed image data supplied to the image processing IP core 22 and the source driver circuit 23. Control data instructing to supply image data in which the gradation value of the 8R, G sub-pixel 8G, and B sub-pixel 8B is the maximum gradation value and the gradation value of the F sub-pixel 8F is the minimum gradation value is provided. Send to display driver 2. While the source driver circuit 23 drives the display panel 1 according to the processed image data generated in this way, the color adjustment software 13 controls the luminance meter 11 and displays it on the display panel 1. Measure the luminance coordinate data of the displayed color. The luminance coordinate data acquired in this way is the luminance coordinate data of the white point (WP).

The chromaticity diagram of FIG. 9 illustrates the luminance coordinate data of the primary color R, the primary color G, the primary color B and the color F of the maximum gradation value in the xyY color system, and the luminance coordinate data of the white point (WP). There is.

In the above, the brightness coordinate data of the primary color R, the primary color G, the primary color B and the color F of the maximum gradation value, and the brightness coordinate of the white point (WP) are obtained by actually performing the measurement on the display panel 1. Although the data has been acquired, from the design data of the display panel 1 (for example, the data showing the characteristics of the filter provided on the display panel 1), the primary colors R, primary colors G, primary colors B, and colors F having the maximum gradation values are obtained. The brightness coordinate data and the brightness coordinate data of the white point (WP) may be acquired.

With reference to FIG. 8 again, following step S01, for the display panel 1, an image is obtained using only the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B (without using the F sub-pixel 8F). The RGB-XYZ conversion matrix M representing the display characteristics of the display panel 1 when displayed and the XYZ-RGB conversion matrix M ^-1 which is an inverse matrix thereof are calculated (step S02). In one embodiment, the RGB-XYZ conversion matrix M and the XYZ-RGB conversion matrix M ^-1 are calculated according to the following procedure.

ここで、ｒ、ｇ、ｂは、それぞれ、ホワイトポイントの輝度を１としたときの原色Ｒ、Ｇ、Ｂの輝度を表しており、下記の連立方程式（１ｂ）を解くことによって得られる：

First, an RGB-XYZ conversion matrix representing the display characteristics of the display panel 1 is calculated based on the luminance coordinate data of the primary colors R, primary colors G, primary colors B, and white point (WP) of the maximum gradation values acquired in step S01. Will be done. The RGB-XYZ transformation matrix is calculated as the transformation matrix M of the following equation (1a):

Here, r, g, and b represent the luminance of the primary colors R, G, and B, respectively, when the luminance of the white point is 1, and can be obtained by solving the following simultaneous equations (1b):

The XYZ-RGB conversion matrix is obtained as an inverse matrix M ^-1 of the RGB-XYZ conversion matrix M. That is, the XYZ-RGB conversion matrix M ^-1 is represented by the following equation (2):

Further, the RGB data (FR, FG, FB) of the color F is calculated based on the luminance coordinate data (FY, Fx, Fy) of the color F having the maximum gradation value and the XYZ-RGB conversion matrix M ^-1 . (Step S03). The RGB data (FR, FG, FB) of the color F drives the F sub-pixel 8F of the display panel 1 with a drive signal corresponding to the maximum gradation value, and other sub-pixels (R sub-pixel 8R, G sub-pixel 8G). , B sub-pixel 8B), the ratio of the primary color R component, the primary color G component, and the primary color B component of the display color displayed on the display panel 1 in a state of being driven by the drive signal corresponding to the minimum gradation value. It is the data which shows.

Specifically, first, the luminance coordinate data (FY, Fx, Fy) of the color F having the maximum gradation value is the color coordinate data (FX, FY, FZ) of the XYZ color system according to the following (3a) and (3b). Is converted to.
FX = FY × Fx / Fy ・ ・ ・ (3a)
FZ = FY × (1-Fx-Fy) / Fy ... (3b)
As the FY of the color coordinate data of the XYZ color system, the stimulus value FY of the luminance coordinate data is used as it is.

Further, the RGB data (FR, FG, FB) of the color F is calculated by applying the XYZ-RGB conversion matrix to the color coordinate data (FX, FY, FZ) of the color F and performing the XYZ-RGB conversion. .. The RGB data (FR, FG, FB) of the color F is expressed by the following equation (4):

The color correction parameters are calculated using the RGB data (FR, FG, FB) of the color F calculated in this way (steps S04 to S09). The calculation of the color correction parameter is performed by the following procedure.

First, the color correction parameter is initially selected by an appropriate method (step S04). In one embodiment, a color correction parameter prepared in advance in the storage device 15 of the arithmetic unit 12 is selected. If the color correction parameter is not appropriate in a later step, the color correction parameter is adjusted. Therefore, in step S04, the color correction parameter may be appropriately selected.

Subsequently, it is determined whether or not the selected color correction parameter is appropriate (steps S05 to S08).

Specifically, the color correction process is performed on the RGB data (Ri, Gi, Bi) to be calibrated based on the color correction parameter selected in step S04, and the color-corrected RGB data (Rc, Gc, Bc) is obtained. It is calculated (step S05). As described above, the RGB data to be calibrated (Ri, Gi, Bi) is the RGB data to be determined whether the color correction parameter is appropriate. The color adjustment software 13 is configured to perform the same color correction processing as the color correction processing performed in the color correction circuit 28 of the image processing IP core 22 of the display driver 2 by software processing, and in step S05, the color is corrected. The same color correction process as the color correction process performed in the correction circuit 28 is executed by the color adjustment software 13, and the color-corrected RGB data (Rc, Gc, Bc) is calculated. When a plurality of sets of the RGB data to be calibrated (Ri, Gi, Bi) and the target RGB data (Rt, Gt, Bt) are prepared, each of the plurality of RGB data to be calibrated (Ri, Gi, Bi) is prepared. A plurality of color-corrected RGB data (Rc, Gc, Bc) corresponding to the above are calculated.

Subsequently, color addition processing is performed on the color-corrected RGB data (Rc, Gc, Bc) to calculate FRGB data (Fa, Ra, Ga, Ba) (step S06). The color adjustment software 13 is configured to perform the same color addition processing as the color addition processing performed in the color addition processing circuit 29 of the image processing IP core 22 of the display driver 2 by software processing, and in step S06, the color adjustment software 13 is configured to perform the same color addition processing. The same color addition process as the color addition process performed in the color addition process circuit 29 is executed by the color adjustment software 13, and FRGB data (Fa, Ra, Ga, Ba) is calculated. When a plurality of sets of the RGB data to be calibrated (Ri, Gi, Bi) and the target RGB data (Rt, Gt, Bt) are prepared, that is, a plurality of color-corrected RGB data (Rc, Gc, Bt) are prepared in step S06. When Bc) is calculated, a plurality of FRGB data (Fa, Ra, Ga, Ba) corresponding to each are calculated.

ここで、γは、表示装置１００に設定されるガンマ値である。また、ＦＲＧＢ_ＭＡＸは、ＦＲＧＢデータ（Ｆａ，Ｒａ，Ｇａ，Ｂａ）に記述されたＲ副画素８Ｒ、Ｇ副画素８Ｇ、Ｂ副画素８Ｂ、Ｆ副画素８Ｆの階調値に許容される最大階調値であり、Ｒ副画素８Ｒ、Ｇ副画素８Ｇ、Ｂ副画素８Ｂ、Ｆ副画素８Ｆの階調値が８ビットで表される場合、ＦＲＧＢ_ＭＡＸは“２５５”である。この場合、式（５ａ）～（５ｃ）は、下記式（５ａ’）～（５ｃ’）に書き直すことができる：

Subsequently, the RGB luminance component data (Rr, Gr, Br) is calculated from the FRGB data (Fa, Ra, Ga, Ba) using the RGB data (FR, FG, FB) of the color F calculated in step S03. (Step S07). The RGB luminance component data (Rr, Gr, Br) is the primary color R, primary color G, of the color displayed on the display panel 1 when the display panel 1 is driven based on the FRGB data (Fa, Ra, Ga, Ba). It is data showing the luminance component of the primary color B, and in this embodiment, the RGB luminance component data (Rr, Gr, Br) is calculated according to the following formulas (5a) to (5c):

Here, γ is a gamma value set in the display device 100. Further, FRGB _MAX is the maximum scale allowed for the gradation values of the R sub-pixel 8R, the G sub-pixel 8G, the B sub-pixel 8B, and the F sub-pixel 8F described in the FRGB data (Fa, Ra, Ga, Ba). The FRGB _MAX is "255" when the gradation value of the R sub-pixel 8R, the G sub-pixel 8G, the B sub-pixel 8B, and the F sub-pixel 8F is represented by 8 bits. In this case, the equations (5a) to (5c) can be rewritten into the following equations (5a') to (5c'):

Based on the calculated RGB luminance component data (Rr, Gr, Br), it is determined whether or not the color correction parameter selected in step S04 is appropriate (step S08). As described above, the RGB luminance component data (Rr, Gr, Br) is the primary color of the color displayed on the display panel 1 when the display panel 1 is driven based on the FRGB data (Fa, Ra, Ga, Ba). The luminance components of R, the primary color G, and the primary color B are shown. Therefore, it is possible to determine whether or not the color correction parameter is appropriate based on the RGB luminance component data (Rr, Gr, Br) and the target RGB data (Rt, Gt, Bt). For example, when the RGB luminance component data (Rr, Gr, Br) calculated in step S08 matches the target RGB data (Rt, Gt, Bt) or is close to the target RGB data (Rt, Gt, Bt). It is determined that the color correction parameter is appropriate. On the other hand, when the RGB luminance component data (Rr, Gr, Br) is significantly different from the target RGB data (Rt, Gt, Bt), it is determined that the color correction parameter is not appropriate.

一実施形態では、距離Ｄが所定値よりも小さい場合に色補正パラメータが適正であると判断され、そうでない場合、色補正パラメータが適正でないと判断されてもよい。 In one embodiment, the similarity between the RGB luminance component data (Rr, Gr, Br) and the target RGB data (Rt, Gt, Bt) may be calculated. In one embodiment, the similarity between the RGB luminance component data (Rr, Gr, Br) and the target RGB data (Rt, Gt, Bt) may be calculated as the distance D defined by the following equation (6). :

In one embodiment, if the distance D is smaller than a predetermined value, it may be determined that the color correction parameter is appropriate, and if not, it may be determined that the color correction parameter is not appropriate.

When a plurality of sets of the RGB data to be calibrated (Ri, Gi, Bi) and the target RGB data (Rt, Gt, Bt) are prepared, the RGB luminance component data (Rr, Gr, Br) corresponding to each set are prepared. ) And the target RGB data (Rt, Gt, Bt), the similarity (distance D) is calculated for each set, and it is determined whether or not the color correction parameter is appropriate based on the calculated similarity. May be good. In one embodiment, based on the sum of the similarity (distance D) calculated for each set of RGB luminance component data (Rr, Gr, Br) and target RGB data (Rt, Gt, Bt). It may be determined whether or not the color correction parameter is appropriate.

If it is determined in step S08 that the color correction parameter is not appropriate, the color correction parameter is adjusted (step S09), and further, whether or not the adjusted color correction parameter is appropriate is determined again by the above procedure. (Steps S05 to S08). Specifically, the color correction process is performed on the RGB data (Ri, Gi, Bi) to be calibrated based on the adjusted color correction parameters, and the color-corrected RGB data (Rc, Gc, Bc) is calculated ( Step S05) Further, color addition processing is performed on the color-corrected RGB data (Rc, Gc, Bc) to calculate FRGB data (Fa, Ra, Ga, Ba) (step S06). Further, the RGB brightness component data (Rr, Gr, Br) is calculated from the FRGB data (Fa, Ra, Ga, Ba) using the RGB data (FR, FG, FB) of the color F calculated in step S03. (Step S07), based on the calculated RGB brightness component data (Rr, Gr, Br), it is determined whether or not the color correction parameter obtained by the adjustment in step S09 is appropriate (step S08). The adjustment of the color correction parameter and the determination of the appropriateness of the color correction parameter are repeated until the color correction parameter is determined to be appropriate.

When it is determined that the color correction parameter is appropriate, the color correction parameter is transmitted from the arithmetic unit 12 to the display driver 2 and written in the color correction parameter storage area 31 of the non-volatile memory 26 of the display driver 2 (step S10). ). This completes the calculation of the color correction parameters and the setting of the calculated color correction parameters in the display driver 2.

According to the procedure for calculating the color correction parameters described above, even when the color changes due to the color addition process, the desired color adjustment (for example, the desired color gamut adjustment) is performed in consideration of the color change. It can be realized.

In the above-mentioned procedure for calculating the color correction parameter, the color coordinate data of the color F having the maximum gradation value (more specifically, the brightness coordinate data (FY, Fx, Fy) of the color F having the maximum gradation value) is used. Although the appropriateness of the color correction parameter is determined, in addition, the appropriateness of the color correction parameter may be determined using the color coordinate data of the color F having a specific intermediate gradation value mid. Strictly speaking, the color coordinate data of the color F of the intermediate gradation value mid is that the R subpixel 8R, the G subpixel 8G, and the B subpixel 8B of the display panel 1 are driven by the drive signal corresponding to the minimum gradation value. The data indicates the color coordinates of the display color displayed on the display panel 1 when the F sub-pixel 8F is driven by the drive signal corresponding to the intermediate gradation value mid in a predetermined color space. Here, the intermediate gradation value mid is a predetermined gradation value that is larger than the minimum gradation value and smaller than the maximum gradation value. When the gradation value of the F subpixel 8F is represented by 8 bits in the output FRGB data, the minimum gradation value is "0" and the maximum gradation value is "255". In this case, the intermediate gradation value. The mid is determined to be an integer value greater than 0 and less than 255. By additionally using the color coordinate data of the color F having the intermediate gradation value mid, the appropriateness of the color correction parameter can be determined more accurately.

As the color coordinate data of the color F of the intermediate gradation value mid, the luminance coordinate data (FY ^mid , Fx ^mid , Fy ^mid ) of the color F of the intermediate gradation value mid may be used. Here, FY ^mid is the stimulus value Y of the color F of the intermediate gradation value mid, and Fx ^mid and Fy ^mid are the chromaticity coordinates x and y of the color F of the intermediate gradation value mid, respectively. In the following, in addition to the luminance coordinate data (FY, Fx, Fy) of the color F of the maximum gradation value, the luminance coordinate data (FY ^mid , Fx ^mid , Fy ^mid ) of the color F of the intermediate gradation value mid is used for the color. The calculation of the color correction parameter when determining the appropriateness of the correction parameter will be described. In the following, in order to clearly distinguish from the brightness coordinate data (FY ^mid , Fx ^mid , Fy ^mid ) of the color F of the intermediate gradation value mid, the brightness coordinate data (FY,) of the color F of the maximum gradation value is used. Fx, Fy) is described as (FY ^max , Fx ^max , Fy ^max ).

FIG. 10 is a flowchart showing a procedure for calculating a color correction parameter when determining the appropriateness of the color correction parameter using the luminance coordinate data (FY ^mid , Fx ^mid , Fy ^mid ) of the color F having an intermediate gradation value mid. Is.

The luminance coordinate data of the primary color R, the primary color G, the primary color B and the color F of the maximum gradation value, and the luminance coordinate data of the white point (WP) are acquired (step S11). The luminance coordinate data of the primary color R, the primary color G, the primary color B and the color F of the maximum gradation value, and the luminance coordinate data of the white point (WP) are performed in the same manner as in step S01 described above.

Further, the luminance coordinate data of the color F having the intermediate gradation value mid is acquired (step S12). The brightness coordinate data of the color F of the intermediate gradation value mid drives the F sub-pixel 8F of the display panel 1 with the drive signal corresponding to the intermediate gradation value mid, and other sub-pixels (R sub-pixel 8R, G sub-pixel). Stimulation value Y and chromaticity coordinates (x, y) in the xyY color system of the display color displayed on the display panel 1 in a state where 8G, B sub-pixel 8B) is driven by a drive signal corresponding to the minimum gradation value. Is acquired as data containing.

In one embodiment, in the acquisition of the brightness coordinate data of the color F having the intermediate gradation value mid, the color adjustment software 13 supplies all the pixels 10 as the processed image data supplied to the source driver circuit 23 to the image processing IP core 22. Instructs to supply image data in which the gradation value of the F sub-pixel 8F is the intermediate gradation value mid and the gradation value of the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B is the minimum gradation value. The control data to be output is transmitted to the display driver 2. While the source driver circuit 23 drives the display panel 1 according to the processed image data generated in this way, the color adjustment software 13 controls the luminance meter 11 and displays it on the display panel 1. Measure the luminance coordinate data of the display color. The luminance coordinate data acquired in this way is the luminance coordinate data of the color F having the intermediate gradation value mid.

Subsequently, regarding the display panel 1, the display characteristics of the display panel 1 when an image is displayed using only the R sub-pixel 8R, the G sub-pixel 8G, and the B sub-pixel 8B (without using the F sub-pixel 8F) are shown. The RGB-XYZ conversion matrix M and its inverse matrix XYZ-RGB conversion matrix M ^-1 are calculated (step S13). The calculation of the RGB-XYZ conversion matrix M and the XYZ-RGB conversion matrix M ^-1 is performed in the same manner as in step S02 described above. The RGB-XYZ conversion matrix is calculated according to the above formula (1a), and the XYZ-RGB conversion matrix M ^-1 is calculated according to the above formula (2).

Further, based on the luminance coordinate data (FY ^max , Fx ^max , Fy ^max ) of the color F having the maximum gradation value and the XYZ-RGB conversion matrix M ^-1 , the RGB data (FR ^max ) of the color F having the maximum gradation value. , FG ^max , FB ^max ) is calculated, and further, it is intermediate based on the luminance coordinate data (FY ^mid , Fx ^mid , Fy ^mid ) of the color F of the intermediate gradation value mid and the XYZ-RGB conversion matrix M ^-1 . RGB data (FR ^mid , FG ^mid , FB ^mid ) of the color F of the gradation value mid is calculated (step S14). Here, the RGB data (FR ^max , FG ^max , FB ^max ) of the color F having the maximum gradation value drives the F sub-pixel 8F of the display panel 1 with the drive signal corresponding to the maximum gradation value, and other subs. Primary color R component, primary color G of the display color displayed on the display panel 1 in a state where the pixels (R sub-pixel 8R, G sub-pixel 8G, B sub-pixel 8B) are driven by the drive signal corresponding to the minimum gradation value. It is data which shows the ratio of the component of, and the component of the primary color B. Further, the RGB data (FR ^mid , FG ^mid , FB ^mid ) of the color F of the intermediate gradation value mid drives the F sub-pixel 8F of the display panel 1 with the drive signal corresponding to the intermediate gradation value mid, and other Primary color R component and primary color of the display color displayed on the display panel 1 in a state where the sub-pixels (R sub-pixel 8R, G sub-pixel 8G, B sub-pixel 8B) are driven by the drive signal corresponding to the minimum gradation value. It is data which shows the ratio of the component of G and the component of primary color B.

More specifically, the RGB data (FR ^max , FG ^max , FB ^max ) of the color F having the maximum gradation value is calculated as follows. The luminance coordinate data (FY ^max , Fx ^max , Fy ^max ) of the color F of the maximum gradation value is converted into the color coordinate data (FX, FY, FZ) of the XYZ color system according to the following (7a) and (7b). To.
FX ^max = FY ^max x Fx ^max / Fy ^max ... (7a)
FZ ^max = FY ^max × (1-Fx ^max -Fy ^max ) / Fy ^max ... (7b)
As the FY ^max of the color coordinate data of the XYZ color system, the stimulation value FY ^max of the luminance coordinate data is used as it is.

Further, by applying the XYZ-RGB conversion matrix to the color coordinate data (FX ^max , FY ^max , FZ ^max ) and performing the XYZ-RGB conversion, the RGB data (FR ^max , FG ^max ) of the color F having the maximum gradation value is performed. , FB ^max ) is calculated. The RGB data (FR ^max , FG ^max , FB ^max ) of the color F of the maximum gradation value is expressed by the following equation (8):

The RGB data (FR ^mid , FG ^mid , FB ^mid ) of the color F of the intermediate gradation value mid is also calculated in the same manner. Specifically, the luminance coordinate data (FY ^mid , Fx ^mid , Fy ^mid ) of the color F of the intermediate gradation value mid is the color coordinate data (FX ^mid , FY) of the XYZ color system according to the following (9a) and (9b). It is converted to ^mid , FZ ^mid ).
FX ^mid = FY ^mid x Fx ^mid / Fy ^mid ... (9a)
FZ ^mid = FY ^mid × (1-Fx ^mid -Fy ^mid ) / Fy ^mid ... (9b)
As the FY ^mid of the color coordinate data of the XYZ color system, the stimulus value FY ^mid of the luminance coordinate data is used as it is.

Further, by applying the XYZ-RGB conversion matrix to the color coordinate data (FX ^mid , FY ^mid , FZ ^mid ) and performing the XYZ-RGB conversion, the RGB data (FR ^mid , FG) of the color F having the intermediate gradation value mid is performed. ^mid , FB ^mid ) is calculated. The RGB data (FR ^mid , FG ^mid , FB ^mid ) of the color F of the intermediate gradation value mid is expressed by the following equation (10):

The RGB data (FR ^max , FG ^max , FB ^max ) of the color F having the maximum gradation value calculated in this way and the RGB data (FR ^mid , FG ^mid , FB ^mid ) of the color F having the intermediate gradation value mid are obtained. The color correction parameters are calculated using the data (steps S15 to S21).

First, the color correction parameter is initially selected by an appropriate method (step S15). In one embodiment, a color correction parameter prepared in advance in the storage device 15 of the arithmetic unit 12 is selected. If the color correction parameter is not appropriate in a later step, the color correction parameter is adjusted. Therefore, in step S15, the color correction parameter may be appropriately selected.

Subsequently, it is determined whether or not the selected color correction parameter is appropriate (steps S16 to S20).

Specifically, the color correction process is performed on the RGB data (Ri, Gi, Bi) to be calibrated based on the color correction parameter selected in step S15, and the color-corrected RGB data (Rc, Gc, Bc) is obtained. It is calculated (step S16). The calculation of the color-corrected RGB data (Rc, Gc, Bc) is performed in the same manner as in step S05 described above.

Further, color addition processing is performed on the color-corrected RGB data (Rc, Gc, Bc) to calculate FRGB data (Fa, Ra, Ga, Ba) (step S17). The calculation of the FRGB data (Fa, Ra, Ga, Ba) is performed in the same manner as in step S06 described above.

ＦＲＧＢデータ（Ｆａ，Ｒａ，Ｇａ，Ｂａ）においてＲ副画素８Ｒ、Ｇ副画素８Ｇ、Ｂ副画素８Ｂ、Ｆ副画素８Ｆの階調値が８ビットで表される場合、ＦＲＧＢ_ＭＡＸは“２５５”である。この場合、式（１１ａ）～（１１ｃ）は、下記式（１１ａ’）～（１１ｃ’）に書き直すことができる：

Further, the F gradation value Fa of the FRGB data calculated in step S17, the RGB data (FR ^max , FG ^max , FB ^max ) of the color F of the maximum gradation value calculated in step S14, and the intermediate gradation value mid. From the RGB data (FR ^mid , FG ^mid , FB ^mid ) of the color F of (FR mid, FG mid, FB mid), the RGB data (FR ^intp , FG ^intp , FB ^intp ) of the color F of the F gradation value Fa is calculated (step S18). The RGB data (FR ^intp , FG ^intp , FB ^intp ) of the color F of the F gradation value Fa is the F sub-pixel 8F when the F sub-pixel 8F is driven by the drive signal corresponding to the F gradation value Fa. It is data showing the brightness components of the primary color R, the primary color G, and the primary color B of the displayed display color, and is calculated according to the following formulas (11a) to (11c).

When the gradation values of the R sub-pixel 8R, G sub-pixel 8G, B sub-pixel 8B, and F sub-pixel 8F are represented by 8 bits in the FRGB data (Fa, Ra, Ga, Ba), the FRGB _MAX is "255". Is. In this case, the equations (11a) to (11c) can be rewritten into the following equations (11a') to (11c'):

ここで、γは、表示装置１００に設定されるガンマ値である。 Subsequently, the RGB luminance component data from the FRGB data (Fa, Ra, Ga, Ba) is used from the RGB data (FR ^intp , FG ^intp , FB ^intp ) of the color F of the F gradation value Fa calculated in step S18. (Rr, Gr, Br) is calculated (step S19). The RGB luminance component data (Rr, Gr, Br) is the primary color R, primary color G, of the color displayed on the display panel 1 when the display panel 1 is driven based on the FRGB data (Fa, Ra, Ga, Ba). It is data showing the luminance component of the primary color B, and in this embodiment, the RGB luminance component data (Rr, Gr, Br) is calculated according to the following formulas (12a) to (12c):

Here, γ is a gamma value set in the display device 100.

When the gradation values of the R sub-pixel 8R, G sub-pixel 8G, B sub-pixel 8B, and F sub-pixel 8F are represented by 8 bits in the FRGB data (Fa, Ra, Ga, Ba), the FRGB _MAX is "255". Is. In this case, the equations (12a) to (12c) can be rewritten into the following equations (12a') to (12c'):

Based on the calculated RGB luminance component data (Rr, Gr, Br), it is determined whether or not the color correction parameter selected in step S15 is appropriate (step S20). As described above, the RGB luminance component data (Rr, Gr, Br) is the primary color of the color displayed on the display panel 1 when the display panel 1 is driven based on the FRGB data (Fa, Ra, Ga, Ba). The luminance components of R, the primary color G, and the primary color B are shown. Therefore, it is possible to determine whether or not the color correction parameter is appropriate based on the RGB luminance component data (Rr, Gr, Br) and the target RGB data (Rt, Gt, Bt). Judgment of the appropriateness of the color correction parameter based on the RGB luminance component data (Rr, Gr, Br) is performed in the same manner as in step S08 above.

If it is determined in step S20 that the color correction parameter is not appropriate, the color correction parameter is adjusted (step S21), and further, it is determined again whether or not the adjusted color correction parameter is appropriate by the above-mentioned procedure. (Steps S16 to S20). Color correction processing is performed on the RGB data (Ri, Gi, Bi) to be calibrated based on the adjusted color correction parameters, and the color-corrected RGB data (Rc, Gc, Bc) is calculated (step S16). Further, color addition processing is performed on the color-corrected RGB data (Rc, Gc, Bc) to calculate FRGB data (Fa, Ra, Ga, Ba) (step S17). Further, the RGB data (FR max, FG max, FB max) of the F gradation value Fa of the FRGB data calculated in step S17, the color F of the maximum gradation value, and the RGB data of the color F of the intermediate gradation value mid (FR ^max , FG ^max , FB ^max ). From FR ^mid , FG ^mid , FB ^mid ), RGB data (FR ^intp , FG ^intp , FB ^intp ) of the color F of the F gradation value Fa is calculated (step S18). Further, using the RGB data (FR ^intp , FG ^intp , FB ^intp ) of the color F of the F gradation value Fa calculated in step S18, the RGB brightness component data (Fa, Ra, Ga, Ba) is used as the RGB brightness component data (Fa, Ra, Ga, Ba). Rr, Gr, Br) is calculated, and it is determined whether or not the adjusted color correction parameter is appropriate based on the calculated RGB brightness component data (Rr, Gr, Br) (step S20). The adjustment of the color correction parameter and the determination of the appropriateness of the color correction parameter are repeated until the color correction parameter is determined to be appropriate.

When it is determined that the color correction parameter is appropriate, the color correction parameter is transmitted from the arithmetic unit 12 to the display driver 2 and written in the color correction parameter storage area 31 of the non-volatile memory 26 of the display driver 2 (step S10). ). This completes the calculation of the color correction parameters and the setting of the calculated color correction parameters in the display driver 2.

According to the procedure for calculating the color correction parameter shown in FIG. 10, even when the color changes due to the color addition process, the desired color adjustment (for example, the desired color gamut adjustment) is performed in consideration of the color change. ) Can be realized. Further, in the procedure shown in FIG. 10, in addition to the brightness coordinate data (FY ^max , Fx ^max , Fy ^max ) of the color F having the maximum gradation value, the brightness coordinate data (FY) of the color F having the intermediate gradation value mid is added. Since the appropriateness of the color correction parameter is determined using ^mid , Fx ^mid , Fy ^mid ), the appropriateness of the color correction parameter can be determined more accurately.

In the above-described embodiment, the color correction parameter to be set in the color correction circuit 28 is calculated by the arithmetic unit 12 of the color adjustment device 200, and the calculated color correction parameter is the non-volatility of the display driver 2 from the color adjustment device 200. Although it is written in the memory 26, the method of calculating and setting the color correction parameter can be changed in various ways.

11 and 12 are block diagrams schematically showing the configurations of the luminance coordinate measuring device 200A and the display device 100 in another embodiment. With reference to FIG. 11, in the present embodiment, the luminance coordinate measuring device 200A for measuring the luminance coordinate data is used instead of the color adjusting apparatus 200. Further, in the non-volatile memory 26 of the display driver 2, in addition to the color correction parameter storage area 31 for storing the color correction parameter, a luminance coordinate data storage area 32 for storing the luminance coordinate data is prepared.

The luminance coordinate measuring device 200A includes a luminance meter 11 and an arithmetic unit 12, and the luminance coordinate data measuring software 18 is installed in the arithmetic unit 12. The measurement of the luminance coordinate data is executed by the arithmetic unit 12 executing the luminance coordinate data measurement software 18. When the color correction parameter is calculated by the procedure of FIG. 8, the luminance coordinate data of the primary color R, the primary color G, the primary color B, and the color F of the maximum gradation value and the luminance coordinate data of the white point (WP) are measured. When the color correction parameter is calculated by the procedure of FIG. 10, in addition, the luminance coordinate data of the color F having the intermediate gradation value mid is measured. The measured luminance coordinate data is written in the luminance coordinate data storage area 32 of the display driver 2.

As shown in FIG. 12, in the present embodiment, in the mounting of the display device 100, the display system is configured by the host 3 and the display device 100. In this display system, the color correction parameters to be set in the color correction circuit 28 are calculated by the host 3. The color adjustment software 41 is installed in the host 3, and the color correction parameters are calculated by the host 3 executing the color adjustment software 41.

When the display system is started, as shown in FIG. 12, the luminance coordinate data written in the luminance coordinate data storage area 32 of the non-volatile memory 26 is read out from the display driver 2 to the host 3. Transferred. The host 3 calculates the color correction parameter to be set in the color correction circuit 28 by the procedure described above from the read luminance coordinate data. In this configuration, the target RGB data (Rt, Gt, Bt) used for the color correction parameter is stored in the storage device of the host 3. The color correction parameter calculated by the host 3 is transferred to the display driver 2 and written in the color correction parameter storage area 31 of the non-volatile memory 26 of the display driver 2.

In the actual operation of the display driver 2, as shown in FIG. 13, the color correction parameter is read from the color correction parameter storage area 31 to the register circuit 25, and the read color correction parameter is the register circuit. It is supplied from 25 to the color correction circuit 28. The host 3 supplies image data to the display driver 2. The color correction circuit 28 performs color correction processing on the image data supplied from the host 3 based on the color correction parameters received from the register circuit 25.

Such a configuration is useful for the user of the display device 100 to perform the desired color adjustment. The manufacturer of the display device 100 writes the luminance coordinate data measured by the luminance coordinate measuring device 200A into the non-volatile memory 26 of the display driver 2. The user of the display device 100 can accurately perform the desired color adjustment by executing the desired color adjustment software 41 by the host 3.

14 and 15 are block diagrams schematically showing the configurations of the luminance coordinate measuring device 200A and the display device 100 in still another embodiment. As shown in FIG. 14, in the present embodiment, the non-volatile memory 26 of the display driver 2 includes a color correction parameter storage area 31 for storing color correction parameters and a general-purpose memory area 33. The luminance coordinate data measured by the luminance coordinate measuring device 200A is written in the general-purpose memory area 33 of the display driver 2.

As shown in FIG. 15, in the present embodiment as well, in the mounting of the display device 100, the display system is configured by the host 3 and the display device 100. In the display system, when calculating the color correction parameter, the luminance coordinate data written in the general-purpose memory area 33 is read out and transferred from the display driver 2 to the host 3. The color adjustment software 41 is installed in the host 3, and the host 3 calculates the color correction parameters to be set in the color correction circuit 28 by the above-mentioned procedure from the read luminance coordinate data. The color correction parameter calculated by the host 3 is transferred to the display driver 2 and written in the color correction parameter storage area 31 of the non-volatile memory 26 of the display driver 2. After that, the general-purpose memory area 33 in which the luminance coordinate data is written is opened for purposes other than holding the luminance coordinate data.

Such a configuration is useful for effectively utilizing the non-volatile memory 26 of the display driver 2. The luminance coordinate data does not necessarily have to be retained after the calculation of the color correction parameter set in the color correction circuit 28 is completed. If the color correction parameter set in the color correction circuit 28 is calculated only once, the general-purpose memory area 33 that stores the luminance coordinate data holds the luminance coordinate data after the calculation of the luminance coordinate parameter is completed. The non-volatile memory 26 can be effectively used by using it for purposes other than the above. In addition, in order to enable color adjustment, that is, calculation of the color correction parameter of the color correction circuit 28 at a desired timing, the luminance coordinate data may be continuously held in the general-purpose memory area 33. ..

16 and 17 are block diagrams schematically showing the configurations of the luminance coordinate measuring device 200A and the display device 100 in still another embodiment. As shown in FIG. 16, in the present embodiment, the non-volatile memory 26 of the display driver 2 includes a luminance coordinate data / color correction parameter storage area 34. The luminance coordinate data measured by the luminance coordinate measuring device 200A is written in the luminance coordinate data / color correction parameter storage area 34 of the display driver 2.

As shown in FIG. 17, in the present embodiment as well, in the mounting of the display device 100, the display system is configured by the host 3 and the display device 100. In the present embodiment, the host 3 includes a luminance coordinate data storage memory 42.

In the display system, when calculating the color correction parameter, the luminance coordinate data / luminance coordinate data written in the luminance coordinate parameter storage area 34 is read out and transferred from the display driver 2 to the host 3 to be transferred to the host 3. It is written to the luminance coordinate data storage memory 42. The color adjustment software 41 is installed in the host 3, and the host 3 uses the luminance coordinate data stored in the luminance coordinate data storage memory 42 to set the color correction parameters to be set in the color correction circuit 28 by the procedure described above. Is calculated. The color correction parameter calculated by the host 3 is transferred to the display driver 2 and written in the luminance coordinate data / color correction parameter storage area 34 of the display driver 2. When writing the color correction parameter, the luminance coordinate data / luminance coordinate data stored in the luminance coordinate parameter storage area 34 is overwritten by the luminance coordinate parameter. According to such a configuration, the capacity of the non-volatile memory 26 of the display driver 2 can be reduced.

The luminance coordinate data stored in the luminance coordinate data storage memory 42 of the host 3 may be retained or discarded after the color correction parameter is calculated. When the color adjustment, that is, the calculation of the color correction parameter set in the color correction circuit 28 can be executed at a desired timing, the luminance coordinate data is continuously held in the luminance coordinate data storage memory 42. On the other hand, when the color correction parameter is calculated only once, the luminance coordinate data is discarded after the color correction parameter is calculated. In this case, a general-purpose memory may be used as the luminance coordinate data storage memory 42. After calculating the color correction parameters, the general-purpose memory may be used for purposes other than holding the luminance coordinate data. Such a configuration is preferable for effective use of memory resources.

Although the embodiments of the present invention are specifically described above, the present invention should not be construed as being limited to the above embodiments. It will be obvious to those skilled in the art that the present invention can be implemented with various modifications. In particular, in the present invention, not only the display driver configured as a dedicated semiconductor integrated circuit for driving the display panel but also the touch panel controller that operates for touch detection of the touch panel is monolithically integrated (that is, on the same chip). Note that it should be interpreted as including the indicated display driver.

100: Display device 200: Color adjustment device 200A: Brightness coordinate measurement device 1: Display panel 2: Display driver 3: Host 4: Active area 5: Gate driver circuit 6: Gate line 7: Source line 8: Pixel circuit 8F: F Sub-pixel 8R: R Sub-pixel 8G: G Sub-pixel 8B: B Sub-pixel 10: Pixel 11: Brightness meter 12: Arithmetic device 13: Color adjustment software 14: Interface 15: Storage device 16: Processor 17: Interface 18: Brightness coordinates Data measurement software 21: Interface circuit 22: Image processing IP core 23: Source driver circuit 24: Panel interface circuit 25: Register circuit 26: Non-volatile memory 27: Timing controller 28: Color correction circuit 29: Color addition processing circuit 31: Color Correction parameter storage area 32: Brightness coordinate data storage area 33: General-purpose memory area 34: Color correction parameter storage area 41: Color adjustment software 42: Brightness coordinate data storage area

Claims (6)

Determines color correction parameters for a display driver that includes a plurality of pixels, each of which comprises an R subpixel, a G subpixel, a B subpixel, and an F subpixel. How to do
(A) The R sub-pixel, the G sub-pixel, and the B sub-pixel are driven by a drive signal corresponding to the minimum gradation value, and the F sub-pixel is driven by a drive signal corresponding to the maximum gradation value. The step of acquiring the first color coordinate data in a predetermined color space of the first display color displayed on the display panel according to the above.
(B) A step of preparing the RGB data to be calibrated and the target RGB data representing the target color to be realized when the color correction process and the color addition process are performed on the RGB data to be calibrated.
(C) A step of performing the color correction process on the calibration target RGB data according to the evaluation target color correction parameter that specifies the mode of the color correction process to generate the evaluation target color corrected RGB data.
(D) A step of performing the color addition process on the RGB data after color correction for evaluation to generate evaluation target FRGB data.
(E) The RGB brightness component data representing the color displayed on the display panel in RGB format when the display panel is driven according to the evaluation target FRGB data is the evaluation target FRGB data and the first color coordinates. Steps to make decisions based on data and
(F) A step of determining the evaluation target color correction parameter as the color correction parameter according to the determination that the RGB luminance component data matches or is close to the target RGB data.
(G) After adjusting the evaluation target color correction parameter to a different color correction parameter in response to the determination that the RGB luminance component data does not match the target RGB data and is not near , the above (c) to ( e ). ) Step to repeat step
And how to equip. In addition,
When the R subpixel, the G subpixel, and the B subpixel are driven by a drive signal corresponding to the minimum gradation value, and the F subpixel is driven by a drive signal corresponding to the maximum gradation value, the said. An image was displayed using the R subpixel, the G subpixel, and the B subpixel in the color coordinates of the first display color displayed on the display panel in the XYZ color system without using the F subpixel. By operating the XYZ-RGB conversion matrix showing the display characteristics of the display panel in the case, the value FR representing the component of the primary color R of the first display color and the value FG representing the component of the primary color G of the first display color. , And the step of calculating the value FB representing the component of the primary color B of the first display color.
The RGB luminance component data is
A value Rr indicating a component of the primary color R of the color displayed on the display panel when the display panel is driven according to the evaluation target FRGB data, and
A value Gr indicating a component of the primary color G of the color displayed on the display panel when the display panel is driven according to the evaluation target FRGB data, and
A value Br indicating a component of the primary color B of the color displayed on the display panel when the display panel is driven according to the evaluation target FRGB data.
Including and
The evaluation target FRGB data is
The gradation value Fa of the F sub-pixel and
The gradation value Ra of the R subpixel and
The gradation value Ga of the G sub-pixel and
Gradation value Ba of the B sub-pixel
Including and
The following equations (1a) to ( _1c ):

The method according to claim 1, which is calculated according to the above. In addition,
The R subpixel, the G subpixel, and the B subpixel are driven by a drive signal corresponding to the minimum gradation value, and the F subpixel is larger than the minimum gradation value and smaller than the maximum gradation value. A step of acquiring second color coordinate data in the color space of the second display color displayed on the display panel in response to being driven by a drive signal corresponding to the adjustment price.
When the R subpixel, the G subpixel, and the B subpixel are driven by a drive signal corresponding to the minimum gradation value, and the F subpixel is driven by a drive signal corresponding to the maximum gradation value, the said. An image was displayed using the R subpixel, the G subpixel, and the B subpixel in the color coordinates of the first display color displayed on the display panel in the XYZ color system without using the F subpixel. By operating the XYZ-RGB conversion matrix showing the display characteristics of the display panel in the case, the value FR ^max representing the component of the primary color R of the first display color and the value representing the component of the primary color G of the first display color. A step of calculating FG ^max and a value FB ^max representing a component of the primary color B of the first display color, and
When the R subpixel, the G subpixel, and the B subpixel are driven by a drive signal corresponding to the minimum gradation value, and the F subpixel is driven by a drive signal corresponding to the intermediate gradation value, the said. By acting the XYZ-RGB conversion matrix on the color coordinates of the second display color in the XYZ color system displayed on the display panel, a value FR ^mid representing the component of the primary color R of the second display color, the above. A step of calculating a value FG ^mid representing the component of the primary color G of the second display color and a value FB ^mid representing the component of the primary color B of the second display color.
Equipped with
The RGB luminance component data is
A value Rr indicating a component of the primary color R of the color displayed on the display panel when the display panel is driven according to the evaluation target FRGB data, and
A value Gr indicating a component of the primary color G of the color displayed on the display panel when the display panel is driven according to the evaluation target FRGB data, and
A value Br indicating a component of the primary color B of the color displayed on the display panel when the display panel is driven according to the evaluation target FRGB data.
Including and
The evaluation target FRGB data is
The gradation value Fa of the F sub-pixel and
The gradation value Ra of the R subpixel and
The gradation value Ga of the G sub-pixel and
Gradation value Ba of the B sub-pixel
Including and
The step of calculating the RGB luminance component data is
The intermediate gradation value is mid, the maximum gradation value is FRGB _MAX , and the following equations (2a) to (2c):

Using the values FR ^ip , ^FG , ^FB , and gamma value γ set in the display driver, the value Rr, the value Gr, and the value Br are calculated according to the following equation (3a). ~ (3c):

The method of claim 1, comprising the step of calculating according to. Determines color correction parameters for a display driver that includes a plurality of pixels, each of which comprises an R subpixel, a G subpixel, a B subpixel, and an F subpixel. It is a color adjustment device that
Arithmetic logic unit and
Equipped with an interface,
The arithmetic unit is
(A) The R sub-pixel, the G sub-pixel, and the B sub-pixel are driven by a drive signal corresponding to the minimum gradation value, and the F sub-pixel is driven by a drive signal corresponding to the maximum gradation value. The first color coordinate data of the first display color displayed on the display panel in a predetermined color space is acquired according to the above.
(B) The RGB data to be calibrated and the target RGB data representing the target color to be realized when the color correction process and the color addition process are performed on the RGB data to be calibrated are stored.
(C) The color correction process is performed on the calibration target RGB data according to the evaluation target color correction parameter that specifies the mode of the color correction process, and the evaluation target color-corrected RGB data is generated.
(D) The evaluation target FRGB data is generated by performing the color addition processing on the evaluation target color corrected RGB data.
(E) The RGB brightness component data representing the color displayed on the display panel in RGB format when the display panel is driven according to the evaluation target FRGB data is the evaluation target FRGB data and the first color coordinates. Determined based on the data
(F) In response to the determination that the RGB luminance component data matches or is close to the target RGB data, the evaluation target color correction parameter is determined as the color correction parameter.
(G) After adjusting the evaluation target color correction parameter to a different color correction parameter in response to the determination that the RGB luminance component data does not match the target RGB data and is not near , the above (c) to ( e ). ) Is configured to perform the operation again,
The interface is a color adjuster configured to transmit the color correction parameters to the display driver. Determines color correction parameters for a display driver that includes a plurality of pixels, each of which comprises an R subpixel, a G subpixel, a B subpixel, and an F subpixel. It ’s a program to do
In the arithmetic unit, the following steps:
(A) The R sub-pixel, the G sub-pixel, and the B sub-pixel are driven by a drive signal corresponding to the minimum gradation value, and the F sub-pixel is driven by a drive signal corresponding to the maximum gradation value. A step of acquiring color coordinate data in a predetermined color space of the display color displayed on the display panel according to the above.
(C) A step of performing the color correction process on the RGB data to be calibrated according to the color correction parameter to be evaluated to specify the mode of the color correction process to generate the RGB data after the color correction to be evaluated.
(D) A step of generating evaluation target FRGB data by performing color addition processing on the evaluation target color corrected RGB data.
(E) The RGB brightness component data representing the color displayed on the display panel in RGB format when the display panel is driven according to the evaluation target FRGB data is the evaluation target FRGB data and the color coordinate data. Steps to determine based on,
(F) It is said that the RGB brightness component data matches or is close to the target RGB data representing the target color to be realized when the color correction process and the color addition process are performed on the RGB data to be calibrated. A step of determining the evaluation target color correction parameter as the color correction parameter according to the judgment, and
(G) After adjusting the evaluation target color correction parameter to a different color correction parameter according to the determination that the RGB luminance component data does not match the target RGB data and is not near , the above (c) to ( e ) Step to repeat step
A program that runs. A display panel including a plurality of pixels, each of which includes an R subpixel, a G subpixel, a B subpixel, and an F subpixel.
A display driver configured to drive the display panel,
Equipped with a host
The display driver is
A color correction circuit configured to perform the color correction process on the RGB data according to the color correction parameter that specifies the mode of the color correction process and generate the RGB data after the color correction.
A color addition circuit configured to generate FRGB data by performing color addition processing on the color-corrected RGB data, and
A drive unit configured to drive the display panel according to the FRGB data, and a drive unit.
The R sub-pixel, the G sub-pixel, and the B sub-pixel are driven by a drive signal corresponding to the minimum gradation value, and the F sub-pixel is driven by a drive signal corresponding to the maximum gradation value. A non-volatile memory configured to non-volatilely store color coordinate data of the display color displayed on the display panel in a predetermined color space is provided.
The host
(A) Receive the color coordinate data from the display driver and receive it.
(B) Stores the RGB data to be calibrated and the target RGB data representing the target color to be realized when the color correction process and the color addition process are performed on the calibrated RGB data in RGB format. ,
(C) The color correction process is performed on the calibration target RGB data according to the evaluation target color correction parameter that specifies the mode of the color correction process, and the evaluation target color-corrected RGB data is generated.
(D) The evaluation target FRGB data is generated by performing the color addition processing on the evaluation target color corrected RGB data.
(E) The RGB brightness component data representing the color displayed on the display panel in RGB format when the display panel is driven according to the evaluation target FRGB data is the evaluation target FRGB data and the color coordinate data. Determined based on
(F) In response to the determination that the RGB luminance component data matches or is close to the target RGB data, the evaluation target color correction parameter is determined as the color correction parameter.
(G) After adjusting the evaluation target color correction parameter to a different color correction parameter in response to the determination that the RGB luminance component data does not match the target RGB data and is not near , the above (c) to ( e ). ) Is repeated,
(H ) A display system configured to transfer the color correction parameters to be set in the display driver to the display driver.

Images