Method for controlling display unit and display unit

Abstract

To prevent coloring caused by generation of domains.SOLUTION: A display unit 1 comprises liquid crystal panels 100R, 100G, and 100B, and displays an image based on rays of emitted light from the respective liquid crystal panels. A display control circuit 210 of the display unit 1 supplies video data in respective colors of R, G, and B to the corresponding liquid crystal panels. The display control circuit 210 takes a panel pixel with the lowest transmittance, of three panel pixels corresponding to a white side pixel on a domain boundary, as a reference panel pixel, and reduces the gradation level of pixel data supplied to the two panel pixels other than the reference panel pixel, of the three panel pixels, to prevent coloring of the white side pixel.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a display device control method and a display device. [Background technology]

[0002] In a three-panel liquid crystal projector, for example, a liquid crystal panel is prepared for each color of R, G, and B, and a color image is generated by synthesizing the images generated by the liquid crystal panels. The liquid crystal panel used in a liquid crystal projector has pixel electrodes arranged in a matrix on one substrate, a common electrode on the other substrate, and liquid crystal sandwiched between the pixel electrodes and the common electrode. When a voltage corresponding to a grayscale level is held between the pixel electrodes and the common electrode, the orientation state of the liquid crystal molecules is regulated, and the transmittance or reflectance corresponding to the voltage is obtained. Therefore, in the above configuration, among the electric fields acting on the liquid crystal molecules, the electric field in the direction from the pixel electrodes to the common electrode or the opposite direction, that is, perpendicular to the substrate surface, contributes to the control of the transmittance, etc. Hereinafter, the electric field perpendicular to the substrate surface may be referred to as a vertical electric field.

[0003] In recent years, as the gap between pixel electrodes narrows due to miniaturization and high definition, the effect of the electric field generated by the adjacent pixel electrodes, that is, the electric field parallel to the substrate surface, cannot be ignored. Hereinafter, the electric field parallel to the substrate surface may be referred to as the horizontal electric field. When the horizontal electric field is added to the vertical electric field, the alignment of the liquid crystal is poor, that is, a domain occurs, which is visually recognized as a display defect. In order to suppress the display defect due to the domain, for example, the following technology has been proposed. That is, when the horizontal electric field becomes large, specifically, when it is assumed that the difference in voltage applied to the adjacent pixel electrodes is equal to or greater than a threshold value, a technology has been proposed for correcting each of the colors R, G, and B so that the voltage difference becomes small (see, for example, Patent Document 1). Note that such a correction may be called a domain correction.

[0004] Patent Document 1 discloses that the VT characteristics of each of the R, G, and B colors are changed in the same manner based on a correction value for a pixel of a liquid crystal panel where a domain occurs. In the technology disclosed in Patent Document 1, for example, when a first difference between a first gradation level designated to a first subpixel corresponding to a first color of each of the R, G, and B colors in a first pixel and a second gradation level designated to a second subpixel corresponding to the first color in a second pixel adjacent to the first pixel is equal to or greater than a threshold value, the first gradation level is corrected to a first corrected gradation level that is closer to the second gradation level by a first correction amount. In addition, in the technology disclosed in Patent Document 1, a third gradation level designated to a third subpixel corresponding to a second color of each of the R, G, and B colors in the first pixel is corrected to a second corrected gradation level that is closer to the second gradation level by a second correction amount based on a second difference between the first corrected gradation level and the second gradation level in a direction from the second gradation level toward the first gradation level. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-004919 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the voltage ranges used in the liquid crystal panels of R, G, and B are different for each color, the voltage relationship between the liquid crystal panels may be lost and the correction may not be performed correctly when the correction is performed using the technique disclosed in Patent Document 1. One example of a case where the voltage ranges used in the liquid crystal panels of R, G, and B are different for each color is a case where the color modes are different for R, G, and B. [Means for solving the problem]

[0007] A control method for a display device according to one embodiment of the present disclosure is a control method for a display device comprising a first liquid crystal panel, a second liquid crystal panel, and a third liquid crystal panel, and displaying an image based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel, the control method including: supplying pixel data of a first color to the first liquid crystal panel, supplying pixel data of a second color different from the pixel data of the first color to the second liquid crystal panel, and supplying pixel data of a third color different from the pixel data of the first color and the second color to the third liquid crystal panel; and determining a panel pixel having the lowest transmittance among a first panel pixel of the first liquid crystal panel corresponding to a first display pixel in the image, a second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and a third panel pixel corresponding to the first display pixel in the third liquid crystal panel as a reference panel pixel, and lowering a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel, other than the reference panel pixel, among the first panel pixel, the second panel pixel, and the third panel pixel.

[0008] Also, a control method for a display device according to another aspect of the present disclosure is a control method for a display device including a first liquid crystal panel, a second liquid crystal panel, and a third liquid crystal panel, which displays an image based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel, and which includes a correction lookup table storing correction data according to a difference in gradation levels of two adjacent display pixels in the image, the control method including the steps of: acquiring the correction data from the correction lookup table based on pixel data representing the gradation levels of each color of the first display pixel in the image and pixel data representing the gradation level of a second display pixel adjacent to the first display pixel; the first panel pixel corresponding to the first display pixel in the first liquid crystal panel, the second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and the third panel pixel corresponding to the first display pixel in the third liquid crystal panel being a reference panel pixel; lowering a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel based on the correction data; and supplying pixel data in which the gradation levels of the two colors have been corrected based on the correction data to the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each color.

[0009] Also, a display device according to another aspect of the present disclosure includes a first liquid crystal panel, a second liquid crystal panel, a third liquid crystal panel, a storage device that stores a correction lookup table in which correction data corresponding to a difference in gradation levels of two adjacent display pixels in an image displayed based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel is stored, and a control device, wherein the control device acquires correction data from the correction lookup table based on pixel data representing the gradation levels of each color of a first display pixel in the image and pixel data representing the gradation level of a second display pixel adjacent to the first display pixel, The method performs the following operations: a panel pixel having the lowest transmittance among a first panel pixel corresponding to the first display pixel in a liquid crystal panel, a second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and a third panel pixel corresponding to the first display pixel in the third liquid crystal panel is set as a reference panel pixel; a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel is lowered based on the correction data; and pixel data in which the gradation levels of the two colors have been corrected based on the correction data are supplied to the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each color. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing an example of an optical configuration of a display device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a block diagram showing an example of an electrical configuration of the display device. [Diagram 3] FIG. 1 is a diagram showing a configuration of a liquid crystal panel in a display device. [Figure 4] FIG. 2 is a perspective view showing a main structure of a liquid crystal panel. [Diagram 5] FIG. 2 is a cross-sectional view showing the structure of a liquid crystal panel. [Figure 6] FIG. 2 is a block diagram showing an electrical configuration of a liquid crystal panel. [Figure 7] FIG. 2 is a diagram showing a configuration of a pixel circuit in a liquid crystal panel. [Figure 8] 1A and 1B are diagrams illustrating an example of degradation of display quality due to domains. [Figure 9] 1 is a diagram showing the VT characteristics of a liquid crystal panel for each wavelength. [Figure 10] FIG. 13 is a diagram showing an example of the contents stored in a correction LUT. [Figure 11] 4 is a flowchart showing the flow of processing of a control method executed by a display control circuit. [Figure 12] FIG. 11 is a diagram illustrating an example of the operation of the display device. [Figure 13] FIG. 13 is a diagram showing an example of voltages applied to pixel electrodes of sub-pixels in conventional domain correction. [Figure 14] 5A and 5B are diagrams illustrating an example of voltages applied to pixel electrodes of each sub-pixel in the embodiment. [Figure 15] 10 is a flowchart showing a process flow of a control method in a second embodiment. [Figure 16] FIG. 11 is a diagram illustrating an example of the operation of the display device according to the second embodiment. [Figure 17] 11A and 11B are explanatory diagrams of shifting the position of a display pixel by a light path shift element. [Figure 18] 1A and 1B are diagrams illustrating degradation of display quality in a display device including a light path shift element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A display device according to an embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, the dimensions and scale of each part are appropriately different from the actual ones. In addition, since the embodiment described below is a preferred specific example, various technically preferable limitations are attached, but the scope of the present disclosure is not limited to these forms unless otherwise specified in the following description to limit the present disclosure.

[0012] (A: First embodiment) 1 is a diagram showing the optical configuration of a display device 1 according to an embodiment of the present disclosure. The display device 1 is a three-panel liquid crystal projector including a liquid crystal panel 100R, a liquid crystal panel 100G, and a liquid crystal panel 100B. The liquid crystal panel 100R is an example of a first liquid crystal panel in the present disclosure. The liquid crystal panel 100G is an example of a second liquid crystal panel in the present disclosure. The liquid crystal panel 100B is an example of a third liquid crystal panel in the present disclosure.

[0013] The display device 1 includes a lamp unit 2102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 2102 is separated into three primary colors, red (R), green (G) and blue (B), by three mirrors 2106 and two dichroic mirrors 2108 arranged inside. Of these, the R light is incident on the liquid crystal panel 100R, the G light is incident on the liquid crystal panel 100G, and the B light is incident on the liquid crystal panel 100B. The optical path of the B light is longer than that of the other colors, red and green. Therefore, the B light is guided to the liquid crystal panel 100B via a relay lens system 2121 consisting of an entrance lens 2122, a relay lens 2123, and an exit lens 2124 to prevent loss in the optical path.

[0014] The liquid crystal panel 100R has sub-pixel circuits arranged in a matrix, and generates an R transmission image by light transmitted through the liquid crystal elements of the sub-pixel circuits based on a data signal corresponding to R. Similarly, the liquid crystal panel 100G generates a G transmission image based on a data signal corresponding to G, and the liquid crystal panel 100B generates a B transmission image based on a data signal corresponding to B.

[0015] The transmission images of each color generated by the liquid crystal panels 100R, 100G, and 100B are incident on the dichroic prism 2112 from three directions. In the dichroic prism 2112, the R and B light are refracted at 90 degrees, while the G light travels straight. Therefore, after the images of each color are combined, a color image is projected onto the screen 2120 by the projection lens 2114. Note that the transmission images by the liquid crystal panels 100R and 100B are projected after being reflected by the dichroic prism 2112, whereas the transmission image by the liquid crystal panel 100G travels straight and is projected. Therefore, the transmission images by the liquid crystal panels 100R and 100B are in a left-right inverted relationship with the transmission image by the liquid crystal panel 100G.

[0016] Fig. 2 is a block diagram showing an electrical configuration of the display device 1. As shown in Fig. 2, the display device 1 includes a video processing device 200, a storage device 300, and the above-mentioned liquid crystal panels 100R, 100G, and 100B.

[0017] Video data Vda is supplied from a host device (not shown) in synchronization with a synchronization signal Sync. The video data Vda specifies the gradation level of a pixel in an image to be displayed, for example, by 8 bits for each of RGB. One pixel is the smallest unit constituting a color image synthesized by the liquid crystal panel 100R, the liquid crystal panel 100G, and the liquid crystal panel 100B. One pixel is further decomposed into three subpixels: a red subpixel by the liquid crystal panel 100R, a green subpixel by the liquid crystal panel 100G, and a blue subpixel by the liquid crystal panel 100B. The red, green, and blue subpixels are examples of panel pixels in this disclosure. The synchronization signal Sync includes a vertical synchronization signal that instructs the start of vertical scanning of pixels arranged in a matrix, a horizontal synchronization signal that instructs the start of horizontal scanning of one row in the above arrangement, and a clock signal that indicates the timing of one pixel of video data.

[0018] The video processing device 200 includes a display control circuit 210, a processing circuit 220R, a processing circuit 220G, and a processing circuit 220B. The display control circuit 210 processes video data Vda and a synchronization signal Sync to output a control signal Ctr for driving the liquid crystal panel 100R, the liquid crystal panel 100G, and the liquid crystal panel 100B. The control signal Ctr includes a signal required for scanning sub-pixel circuits arranged in a matrix in the liquid crystal panel 100R, the liquid crystal panel 100G, and the liquid crystal panel 100B. In addition, the display control circuit 210 supplies video data Vda_R corresponding to R to the liquid crystal panel 100R, video data Vda_G corresponding to G to the liquid crystal panel 100G, and video data Vda_B corresponding to B to the liquid crystal panel 100B, respectively, in accordance with the output of the control signal Ctr. The video data Vda_R is an example of pixel data of a first color. The video data Vda_G is an example of pixel data of a second color. The video data Vda_B is an example of the third pixel data.

[0019] Furthermore, the display control circuit 210 performs correction to each of the video data Vda_R, Vda_G, and Vda_B as necessary to suppress coloring caused by domains. Details of this correction will be made clear later. The display control circuit 210 is an example of a control device in the present disclosure.

[0020] The processing circuit 220R converts the video data Vda_R supplied from the display control circuit 210 into an analog voltage data signal Vid_R and supplies it to the liquid crystal panel 100R. The processing circuit 220G converts the video data Vda_G supplied from the display control circuit 210 into an analog voltage data signal Vid_G and supplies it to the liquid crystal panel 100G. Similarly, the processing circuit 220B converts the video data Vda_B supplied from the display control circuit 210 into an analog voltage data signal Vid_B and supplies it to the liquid crystal panel 100B.

[0021] The storage device 300 is configured with a non-volatile memory such as a flash ROM (Read Only Memory). A correction lookup table is stored in advance in the storage device 300 for each of the colors R, G, and B. In FIG. 2, the lookup table is written as "LUT", and the same notation will be used hereinafter in this specification. Although details will be described later, the correction LUT stores correction data that indicates the correction value of the gradation level of each color when correcting each of the video data Vda_R, video data Vda_G, and video data Vda_B in order to suppress coloring caused by domains.

[0022] Next, the liquid crystal panels 100R, 100G, and 100B will be described. The liquid crystal panels 100R, 100G, and 100B have the same structure, but the only difference is the color of the light that enters them, i.e., the wavelength. Therefore, the liquid crystal panels 100R, 100G, and 100B will be generally described as 100, without specifying the color.

[0023] FIG. 3 is a diagram showing the configuration of the liquid crystal panel 100, FIG. 4 is a diagram showing a main part of the liquid crystal panel 100, and FIG. 5 is a cross-sectional view taken along line Hh in FIG. 4. As shown in FIG. 3, the liquid crystal panel 100 is housed in a frame-shaped case 72 that opens in the display area. One end of an FPC board 74 is connected to the liquid crystal panel 100. FPC is an abbreviation for Flexible Printed Circuits. A plurality of terminals 76 are provided on the other end of the FPC board 74, and are connected to the video processing device 200.

[0024] As shown in Figures 4 and 5, the liquid crystal panel 100 has a structure in which an element substrate 100a on which a pixel electrode 118 is provided and an opposing substrate 100b on which a common electrode 108 is provided are bonded together so that their electrode forming surfaces face each other while maintaining a certain gap by a sealing material 90 including a spacer (not shown), and liquid crystal 105 is sandwiched in the gap.

[0025] The element substrate 100a and the counter substrate 100b are each made of a light-transmitting material such as glass or quartz. As shown in Fig. 4, one side of the element substrate 100a protrudes from the counter substrate 100b. A plurality of terminals 106 are provided in the protruding area along the X direction. One end of the FPC substrate 74 shown in Fig. 3 is connected to the plurality of terminals 106, and the above-mentioned various signals are supplied.

[0026] On the surface of the element substrate 100a facing the counter substrate 100b, pixel electrodes 118 are formed by patterning a transparent conductive layer such as ITO. ITO is an abbreviation for Indium Tin Oxide. Various elements other than the electrodes are provided on the opposing surfaces of the element substrate 100a and the opposing surfaces of the counter substrate 100b, but are omitted in FIG. 3.

[0027] 6 is a block diagram showing the electrical configuration of the liquid crystal panel 100. In the liquid crystal panel 100, a scanning line driving circuit 130 and a data line driving circuit 140 are provided on the periphery of the display area 10.

[0028] In the display region 10 of the liquid crystal panel 100, sub-pixel circuits 110 corresponding to sub-pixels of an image to be displayed are arranged in a matrix. In detail, in the display region 10, a plurality of scanning lines 12 are provided extending in the X direction in the figure, and a plurality of data lines 14 are provided extending in the Y direction and electrically insulated from the scanning lines 12. The sub-pixel circuits 110 are provided in a matrix corresponding to the intersections of the plurality of scanning lines 12 and the plurality of data lines 14.

[0029] If the number of scanning lines 12 is m and the number of data lines 14 is n, the subpixel circuits 110 are arranged in a matrix of m rows and n columns. Both m and n are integers of 2 or more. In order to distinguish the rows of the matrix in the scanning lines 12 and the subpixel circuits 110, they may be referred to as 1, 2, 3, ..., (m-1), m rows from the top in the figure. Similarly, in order to distinguish the columns of the matrix in the data lines 14 and the subpixel circuits 110, they may be referred to as 1, 2, 3, ..., (n-1), n ​​columns from the left in the figure.

[0030] The scanning line driving circuit 130 selects the scanning lines 12 one by one in the order of, for example, the 1st, 2nd, 3rd, ..., mth rows in accordance with the control by the display control circuit 210, and sets the scanning signal to the selected scanning line 12 to H level. Note that the scanning line driving circuit 130 sets the scanning signal to the scanning lines 12 other than the selected scanning line 12 to L level.

[0031] The data line driving circuit 140 latches one row of data signals supplied from the corresponding color circuit among the processing circuit 220R, the processing circuit 220G, and the processing circuit 220B, and outputs the data signals to the sub-pixel circuit 110 located on the scanning line 12 via the data line 14 during the period when the scanning signal to the scanning line 12 is at H level.

[0032] 7 is a diagram showing an equivalent circuit of four sub-pixel circuits 110 arranged in two rows and two columns corresponding to the intersections of two adjacent scanning lines 12 and two adjacent data lines 14. As shown in Fig. 7, the sub-pixel circuit 110 includes a transistor 116 and a liquid crystal element 120. The transistor 116 is, for example, an n-channel thin film transistor. In the sub-pixel circuit 110, a gate node of the transistor 116 is connected to the scanning line 12, a source node of the transistor 116 is connected to the data line 14, and a drain node of the transistor 116 is connected to a pixel electrode 118 having a substantially square shape in a plan view.

[0033] A common electrode 108 is provided for all pixels in common so as to face the pixel electrode 118. A voltage LCcom is applied to the common electrode 108. As described above, the liquid crystal 105 is sandwiched between the pixel electrode 118 and the common electrode 108. Therefore, for each subpixel circuit 110, a liquid crystal element 120 is formed in which the liquid crystal 105 is sandwiched between the pixel electrode 118 and the common electrode 108. A storage capacitance 109 is provided in parallel with the liquid crystal element 120. One end of the storage capacitance 109 is connected to the pixel electrode 118, and the other end is connected to the capacitance line 107. A time-constant voltage, for example, a voltage LCcom equal to the voltage applied to the common electrode 108, is applied to the capacitance line 107. The subpixel circuits 110 are arranged in a matrix shape in the X direction, which is the extension direction of the scanning lines 12, and the Y direction, which is the extension direction of the data lines 14, and therefore the pixel electrodes 118 included in the subpixel circuit 110 are also arranged in the Y direction and the X direction.

[0034] When the scanning signal of a scanning line 12 becomes H level, the transistor 116 of the sub-pixel circuit 110 provided corresponding to the scanning line 12 is turned on. When the transistor 116 is turned on, the data line 14 and the pixel electrode 118 are electrically connected, so that the data signal supplied to the data line 14 reaches the pixel electrode 118 via the turned-on transistor 116. When the scanning line 12 becomes L level, the transistor 116 is turned off, but the voltage of the data signal that reaches the pixel electrode 118 is held by the capacitive property of the liquid crystal element 120 and the storage capacitance 109.

[0035] As is well known, in the liquid crystal element 120, the orientation of the liquid crystal molecules changes in response to the electric field generated by the pixel electrode 118 and the common electrode 108. Therefore, the liquid crystal element 120 has a transmittance that corresponds to the effective value of the voltage applied thereto. In this embodiment, the transmittance increases as the voltage applied to the liquid crystal element 120 increases.

[0036] The operation of supplying data signals to the pixel electrodes 118 of the liquid crystal elements 120 is performed in the order of the 1st, 2nd, 3rd, ..., mth rows, so that a voltage corresponding to the data signal is held in each of the liquid crystal elements 120 of the sub-pixel circuits 110 arranged in m rows and n columns. By holding such a voltage, each liquid crystal element 120 has a target transmittance, and an image consisting of pixels arranged in m rows and n columns is generated.

[0037] Strictly speaking, the pixel electrode 118 should be called a subpixel electrode because it is provided in the subpixel circuit 110 and is provided to express a subpixel of any color. However, in this embodiment, three subpixels of different colors are combined to express one pixel, and the shape of one pixel is approximately the same as the shape of the pixel electrode 118 when viewed in a plan view, so it is called a pixel electrode.

[0038] In FIG. 6, two scanning line driving circuits 130 are provided, and scanning signals are supplied to the scanning lines 12 from both ends. The reason for this configuration is to suppress the effect of delay of the scanning signal on the display, compared to the case where the scanning signal is supplied from only one end. In addition, when driving the liquid crystal element 120, it is necessary to drive the liquid crystal 105 by AC driving in order to prevent deterioration of the liquid crystal 105, so that a positive polarity voltage on the higher side and a negative polarity voltage on the lower side are alternately switched and applied to the pixel electrode 118 with respect to the voltage at the center of amplitude. In this AC driving, in this embodiment, a surface inversion method is used in which the writing polarity of each liquid crystal element 120 is the same in the vertical scanning of the subpixel circuit 110. The voltage at the center of amplitude here may be considered to be approximately the same voltage as the voltage LCcom applied to the common electrode 108.

[0039] However, when the pixel pitch is narrowed in order to reduce size and increase definition, a domain occurs due to a lateral electric field generated between adjacent pixel electrodes, and this is visually recognized as a display defect.

[0040] FIG. 8 is a diagram showing an enlarged plan view of pixels of a displayed image to explain the degradation of display quality due to domains. In FIG. 8, one square frame represents one pixel. For example, when white characters are displayed on a black background, if the pixels constituting the background and the pixels constituting the white characters are enlarged, the display should be as shown in FIG. 8(1). Note that white here refers to a state in which, for example, three sub-pixels R, G, and B are combined at the highest gradation level, i.e., the maximum transmittance. The open square frame in FIG. 8 represents a white pixel. Black refers to a state in which three sub-pixels R, G, and B are combined at the lowest gradation level, i.e., the minimum transmittance. In FIG. 8, the square frame with diagonal hatching represents a black pixel. In the following, of two adjacent pixels in a displayed image, a pixel in which the three sub-pixels R, G, and B are combined at the maximum transmittance is referred to as a white-side pixel, and a pixel in which the three sub-pixels R, G, and B are combined at the minimum transmittance is referred to as a black-side pixel. Note that the white-side pixel is not limited to a pixel in which the three sub-pixels R, G, and B are combined at the maximum transmittance, and the black-side pixel is not limited to a pixel in which the three sub-pixels R, G, and B are combined at the minimum transmittance. The white-side pixel may be any pixel having a higher gradation level than the black-side pixel. In the following, the sub-pixel corresponding to the white-side pixel may be referred to as a white-side sub-pixel, and the sub-pixel corresponding to the black-side pixel may be referred to as a black-side sub-pixel.

[0041] In this state, when focusing on one color, for example, G, the difference between the voltage of the pixel electrode 118 corresponding to the subpixel corresponding to the white side pixel, specifically the subpixel on the right side in FIG. 8(1), and the voltage of the pixel electrode 118 corresponding to the subpixel corresponding to the black side pixel, specifically the subpixel on the left side in FIG. 8(1), becomes large, so a lateral electric field is generated. Due to this lateral electric field, as shown in FIG. 8(2), a domain Ds occurs near the boundary Edg between the white side subpixel and the black side subpixel, and the display quality is degraded. When the domain Ds occurs as shown in FIG. 8(2), the transmittance of the white side subpixel decreases, and the display quality is degraded. Specifically, the transmittance of the G subpixel corresponding to the white side pixel becomes smaller than the maximum transmittance, and the white side pixel is colored magenta, as shown in FIG. 8(3). In FIG. 8, a square frame with dotted hatching indicates a pixel colored magenta.

[0042] In conventional domain correction for suppressing degradation of display quality due to domains, the voltage applied to the pixel electrodes 118 of the subpixels of each color corresponding to the white side pixel is lowered for each color, thereby reducing the voltage difference between the black side subpixel adjacent to the white side subpixel and the white side subpixel in the liquid crystal panel 100, thereby suppressing the occurrence of domains. In contrast, in this embodiment, the display control circuit 210 corrects the voltage of the data signal so that the transmittance of the three white side subpixels is uniform.

[0043] Specifically, the display control circuit 210 reduces the voltage of the data signal to the pixel electrodes 118 corresponding to the two subpixels on the white side so that the transmittance of the subpixel with the lowest transmittance among the three subpixels on the white side, i.e., the subpixel with the darkest color, remains the same, while the transmittance of each of the remaining two subpixels is reduced. The white side pixel is an example of a first display pixel in this disclosure. The R, G, and B subpixels corresponding to the white side pixel are examples of the first, second, and third panel pixels in this disclosure. The subpixel with the lowest transmittance among the three subpixels on the white side is referred to as the reference panel pixel, and the color of the reference panel pixel is referred to as the reference color.

[0044] The reason for lowering the transmittance of each of the remaining two white sub-pixels while leaving the transmittance of the reference panel pixel unchanged is as follows: Although it may seem that the same effect can be achieved by increasing the transmittance of the reference panel pixel and leaving the transmittance of each of the remaining two white sub-pixels unchanged, the reference panel pixel is a white sub-pixel, and it may not be possible to further increase the transmittance.

[0045] It is becoming known that in the liquid crystal panel 100, the transmittance characteristic with respect to the voltage applied to the liquid crystal element 120 differs for each wavelength of incident light. FIG. 9 is a diagram showing the applied voltage-transmittance characteristic (VT characteristic) for each of the liquid crystal panels 100R, 100G, and 100B. In FIG. 9, the dashed-dotted line graph represents the VT characteristic of the liquid crystal panel 100R, the dotted line graph represents the VT characteristic of the liquid crystal panel 100G, and the solid line graph represents the VT characteristic of the liquid crystal panel 100B. As shown in FIG. 9, even if the voltage applied to the liquid crystal element 120 is the same, the transmittance differs for each wavelength of incident light. In detail, even if the applied voltage is the same, the transmittance of R is lower than the transmittances of B and G. The transmittance here refers to the relative transmittance normalized with the minimum value set to 0 and the maximum value set to 1.

[0046] As described above, in the conventional domain correction, the voltage applied to the pixel electrode 118 of the subpixel of each color on the white side is reduced for each color in order to suppress the domain. However, if the VT characteristics differ for each wavelength of the incident light, the following problem occurs. That is, by reducing the voltage applied to the pixel electrode 118 of the subpixel of each color on the white side for each color, the voltage difference with the adjacent subpixel on the black side becomes smaller, and the domain is improved. However, if the voltage applied to the pixel electrode 118 of the subpixel of each color on the white side is reduced for each color, the variation in the transmittance of each color of R, G, and B increases. In the white side pixel, the transmittance of each color of R, G, and B is ideally 1:1:1, but if the variation in the transmittance of each color of R, G, and B increases, coloring occurs in the white side pixel.

[0047] In contrast, in this embodiment, as shown in Fig. 9, the display control circuit 210 reduces the voltage supplied to each pixel electrode 118 of the remaining two white subpixels, i.e., G and B subpixels, to a voltage represented by correction data stored in the correction LUT corresponding to the reference color so that the transmittance of the R subpixel, which is the reference panel pixel, is matched with the transmittance of the reference panel pixel while keeping the transmittance of the R subpixel unchanged. The process of reducing the voltage supplied to each pixel electrode 118 of the two white subpixels other than the reference panel pixel is called a first correction process. The black circles, triangles, and squares in Fig. 9 represent the transmittance of the R, G, and B subpixels corresponding to the white pixel, respectively. The open triangles and squares in Fig. 9 represent the transmittance of the G and B subpixels after correction by the first correction process, respectively. In this embodiment, as shown in FIG. 9, the transmittances of the three sub-pixels corresponding to the white side pixel are substantially uniform and approximately 1:1:1, so that the coloring of the white side pixel is improved.

[0048] When a predetermined condition is satisfied, such as the coloring of the white side pixel being visually confirmed even after correcting the grayscale levels of the two subpixels on the white side other than the reference panel pixel, i.e., the voltage applied to the pixel electrode 118, the user of the display device 1 can instruct the execution of the second correction process by operating an operation unit (not shown). When the execution of the second correction process is instructed, the display control circuit 210 executes the second correction process. In the second correction process, the voltage supplied to the pixel electrode 118 of the subpixel adjacent to the reference panel pixel among the three subpixels corresponding to the black side pixel adjacent to the white side pixel corresponding to the reference panel pixel is increased to a voltage represented by the correction data stored in the correction LUT. By increasing the voltage supplied to the pixel electrode 118 of the subpixel adjacent to the reference panel pixel, the horizontal electric field between the reference panel pixel and the subpixel adjacent to the reference panel pixel is reduced, and the domain is suppressed. As a result of the domain being suppressed, the transmittance of the reference panel pixel is increased, and the coloring of the white side pixel is suppressed.

[0049] Next, the correction LUT will be described. Since the data structure of the correction LUT corresponding to each color of R, G, and B is the same, the contents stored in the correction LUT will be described below by taking the correction LUT corresponding to R as an example. FIG. 10 is a diagram showing an example of the contents stored in the correction LUT corresponding to R. As shown in FIG. 10, the correction LUT stores correction data representing correction values ​​of the voltages of the subpixels of each color of B and G in the first correction process, in association with the gradation level of the subpixel of R on the black side and the gradation level of the subpixel of R on the white side. When the reference color is R, in the first correction process, the display control circuit 210 reads out correction data representing correction values ​​of the voltages of the subpixels of each color of B and G stored in the correction LUT of R in association with the gradation level of the reference panel pixel and the gradation level of the subpixel on the black side adjacent to the reference panel pixel in the liquid crystal panel 100R, and executes the first correction process using the correction data. Similarly, in the second correction process, the display control circuit 210 reads out correction data representing the correction value of the voltage of the R sub-pixel stored in the R correction LUT in correspondence with the gradation level of the reference panel pixel and the gradation level of the black sub-pixel adjacent to the reference panel pixel in the liquid crystal panel 100R, and performs the second correction process using the correction data.

[0050] The contents stored in the correction LUT may be set according to the VT characteristics. The VT characteristics may be specified by measuring the transmittance of the sub-images of R, G, and B colors in a state where a pattern image in which white, gray, and black pixels are arranged is displayed on the display device 1. The VT characteristics may be specified, for example, for each model of the display device 1, that is, once for each model, and the contents stored in the correction LUT based on the VT characteristics may be set at the time of shipment of the display device 1 from the factory. In addition, in order to perform fine adjustment according to individual differences of the display device 1, the correction amount in the first correction process and the second correction process may be adjusted by multiplying the correction data stored in the correction LUT by a coefficient. In addition, by setting this coefficient according to a function that uses the elapsed time from the shipment of the display device 1 as an argument, the first correction process and the second correction process that take into account aging deterioration can be performed.

[0051] Fig. 11 is a flowchart showing a process flow in a control method executed by the display control circuit 210. As shown in Fig. 11, this control method includes a determination process SA110, a first correction process SA120, a first judgment process SA130, and a second correction process SA140.

[0052] In the determination process SA110, the display control circuit 210 determines a reference color and a reference panel pixel by analyzing each of the video data Vda_R, video data Vda_G, and video data Vda_B. In this embodiment, the display control circuit 210 determines the subpixel with the lowest transmittance among the three subpixels corresponding to the white side pixel adjacent to the black side pixel as the reference panel pixel, and the color corresponding to the reference panel pixel as the reference color. The location where the black side pixel and the white side pixel are adjacent to each other may be called a domain boundary. Note that the transmittance of the three subpixels corresponding to the white side pixel of the domain boundary may be calculated based on, for example, the grayscale levels represented by each of the video data Vda_R, video data Vda_G, and video data Vda_B, and the above-mentioned VT characteristics.

[0053] In the first correction process SA120 following the determination process SA110, the display control circuit 210 lowers the gradation levels represented by the video data corresponding to two sub-pixels other than the reference panel pixel among the three sub-pixels corresponding to the white side pixel at the domain boundary, by referring to the stored contents of the correction LUT corresponding to the reference color. For example, as shown in FIG. 12(1), it is assumed that the transmittance of G among the colors R, G, and B corresponding to the white side pixel at the domain boundary is lower than the other two. In FIG. 12, the diagonal hatching represents black, the vertical hatching represents R, the lattice hatching represents G, and the horizontal hatching represents B. In addition, in FIG. 12, the transmittance of each sub-pixel is represented by the density of the lines constituting the hatching. Specifically, the higher the density of the lines constituting the hatching, the lower the transmittance. In this case, the display control circuit 210 sets the reference color to G, and lowers the transmittance of the sub-pixels of B and R corresponding to the white side pixel as shown in FIG. 12(2). The display control circuit 210 supplies the processing circuit 220B with video data Vda_B in which the gradation level of the B sub-pixel corresponding to the white side pixel of the domain boundary has been corrected, and supplies the processing circuit 220R with video data Vda_R in which the gradation level of the R sub-pixel corresponding to the white side pixel has been corrected. The display control circuit 210 also supplies the uncorrected video data Vda_G to the processing circuit 220G.

[0054] In the first determination process SA130 following the first correction process SA120, the display control circuit 210 determines whether or not execution of the second correction process has been instructed. When the display control circuit 210 receives an operation signal from the operation unit instructing execution of the second correction process, the determination result of the first determination process SA130 is "Yes". In contrast, when the display control circuit 210 receives another operation signal, for example, an operation signal instructing the end of this control method, from the operation unit, the determination result of the first determination process SA130 is "No". When the determination result of the first determination process SA130 is "No", the display control circuit 210 ends execution of this control method. In contrast, when the determination result of the first determination process SA130 is "Yes", the display control circuit 210 executes the second correction process SA140.

[0055] In the second correction process SA140, the display control circuit 210 increases the gradation level represented by the video data corresponding to the subpixel adjacent to the reference panel pixel among the three subpixels corresponding to the black side pixel at the domain boundary, by referring to the stored contents of the correction LUT corresponding to the reference color. As described above, since the reference panel pixel in this operation example is a G subpixel on the white side, by executing the second correction process SA140, the transmittance of the G subpixel corresponding to the black side pixel increases as shown in FIG. 12(3). The display control circuit 210 supplies the video data Vda_G in which the gradation level of the G subpixel corresponding to the black side pixel at the domain boundary has been corrected to the processing circuit 220G, and supplies each of the video data Vda_R and Vda_B corrected in the first correction process SA120 to the processing circuit 220R and the processing circuit 220B, respectively.

[0056] As described above, according to the display device 1 of the first embodiment, the gradation level of pixel data supplied to two sub-pixels other than the reference panel pixel among the sub-pixels of R, G, and B colors corresponding to the white side pixel of the domain boundary is lowered. Therefore, the difference between the transmittance of the reference panel pixel and each of the two sub-pixels is reduced, and coloring of the white side pixel caused by the variation in transmittance is suppressed. Furthermore, according to the display device 1 of the first embodiment, when the second correction process SA140 is executed, the horizontal electric field between the reference panel pixel and the sub-pixel adjacent to the reference panel pixel is reduced, and the domain is suppressed. As a result of the suppression of the domain, the transmittance of the reference panel pixel is increased, and coloring of the white side pixel is suppressed. Thus, according to the display device 1 of the present embodiment, coloring of the white side pixel of the domain boundary can be suppressed.

[0057] In conventional domain correction, the voltage applied to the pixel electrode of all subpixels located on the domain boundary changes from the voltage in a state where no domain occurs, as shown in Fig. 13. In contrast, according to the display device 1 of the first embodiment, as shown in Fig. 14, when, among the subpixels located on the domain boundary, for example, a G subpixel on the white side is a reference panel pixel, the voltage applied to the pixel electrode of the reference panel pixel and the R and B subpixels on the black side does not change from the voltage in a state where no domain occurs.

[0058] The first determination process SA130 in this embodiment is not a required process and may be omitted. In an aspect in which the first determination process SA130 is omitted, the second correction process SA140 is executed following the first correction process SA120. The second correction process SA140 is also not a required process and may be omitted. In other words, the control method of this embodiment may be composed of the determination process SA110 and the first correction process SA120.

[0059] (B: Second embodiment) The display control circuit 210 may execute a control method shown in FIG. 15 instead of the control method shown in FIG. 11. In FIG. 11 and FIG. 15, the same processes are denoted by the same reference numerals. As is clear from comparing FIG. 11 and FIG. 15, the control method in this embodiment is different from the control method in the first embodiment in that it includes a second determination process SA150, a third correction process SA160, a third determination process SA170, and a fourth correction process SA180. In addition, in this embodiment, the correction LUT stores correction data in the third correction process and the fourth correction process in addition to the correction data in the first correction process and the second correction process. For example, in the case of the correction LUT corresponding to R, the correction data in the third correction process includes data representing a correction value of the gradation level of the video data corresponding to the reference panel pixel. Similarly, the correction data in the fourth correction process includes data representing a correction value of the gradation level of the video data of two subpixels other than the subpixel adjacent to the reference panel pixel among the three subpixels corresponding to the black side pixel.

[0060] As shown in FIG. 15, the second determination process SA150 is a process executed following the second correction process SA140. In the second determination process SA150, the display control circuit 210 determines whether or not execution of the third correction process has been instructed. When the display control circuit 210 receives an operation signal from the operation unit instructing execution of the third correction process, the determination result of the second determination process SA150 is "Yes". In contrast, when the display control circuit 210 receives another operation signal, for example, an operation signal instructing the end of this control method, from the operation unit, the determination result of the second determination process SA150 is "No". When the determination result of the second determination process SA150 is "No", the display control circuit 210 ends execution of this control method. In contrast, when the determination result of the second determination process SA150 is "Yes", the display control circuit 210 executes the third correction process SA160.

[0061] In the third correction process SA160, the display control circuit 210 raises the gradation level of the video data corresponding to the reference panel pixel by referring to the stored contents of the correction LUT corresponding to the reference color. The reference panel pixel in this operation example is a G sub-pixel on the white side, as in the operation example in the first embodiment, and it is assumed that the transmittance of the R, G, and B sub-pixels corresponding to the white side pixel is in the state shown in FIG. 16(1) when the third correction process SA160 is started. In FIG. 16, as in FIG. 12, the diagonal hatching represents black, the vertical hatching represents R, the lattice hatching represents G, and the horizontal hatching represents B. In FIG. 16, as in FIG. 12, the transmittance of each subpixel is represented by the density of the lines constituting the hatching. In this case, by executing the third correction process SA160, the transmittance of the G subpixel corresponding to the white side pixel is increased as shown in FIG. 16(2). The display control circuit 210 supplies the processing circuit 220G with video data Vda_G in which the gradation levels of the G subpixels corresponding to the black side pixels and the white side pixels of the domain boundary have been corrected, and supplies the processing circuit 220R and the processing circuit 220B with each of the video data Vda_R and Vda_B corrected by the first correction process SA120. When the third correction process SA160 is executed, the difference between the transmittance of the reference panel pixel and the transmittance of each of the other two sub-pixels on the white side becomes even smaller, and coloring of the white side pixel caused by variations in transmittance is suppressed.

[0062] In the third determination process SA170 following the third correction process SA160, the display control circuit 210 determines whether or not execution of the fourth correction process has been instructed. When the display control circuit 210 receives an operation signal from the operation unit instructing execution of the fourth correction process, the determination result of the third determination process SA170 is "Yes". In contrast, when the display control circuit 210 receives another operation signal, for example, an operation signal instructing the end of this control method, from the operation unit, the determination result of the third determination process SA170 is "No". When the determination result of the third determination process SA170 is "No", the display control circuit 210 ends execution of this control method. In contrast, when the determination result of the third determination process SA170 is "Yes", the display control circuit 210 executes the fourth correction process SA180.

[0063] In the fourth correction process SA180, the display control circuit 210 lowers the gradation level represented by the video data corresponding to the subpixels other than the subpixel adjacent to the reference panel pixel among the three subpixels corresponding to the black side pixel at the domain boundary, by referring to the stored contents of the correction LUT corresponding to the reference color. As described above, the reference panel pixel in this operation example is a G subpixel on the white side, so by executing the fourth correction process SA180, the transmittance of the R and B subpixels corresponding to the black side pixel is reduced as shown in FIG. 16(3). The display control circuit 210 supplies the video data Vda_G in which the gradation level of the G subpixel corresponding to the black side pixel at the domain boundary has been corrected to the processing circuit 220G, and supplies each of the video data Vda_R and Vda_B corrected in the first correction process SA120 to the processing circuit 220R and the processing circuit 220B, respectively. When the fourth correction process SA180 is executed, the gradation level of the black side sub-pixel for each of the R and B colors is raised, strengthening the horizontal electric field at the domain boundary and decreasing the transmittance of each of the R and B sub-pixels. As a result, the variation in the transmittance of each of the R, G, and B sub-pixels corresponding to the white side pixel is further reduced, and the coloring of the white side pixel is further suppressed.

[0064] As described above, according to the control method of the second embodiment, coloring of pixels on the white side of the domain boundary can be further suppressed compared to the first embodiment.

[0065] (C. Transformation) Although the first and second embodiments of the present disclosure have been described above, these embodiments may be modified as follows.

[0066] (C-1: Variation 1) Although the first and second embodiments have been described in a normally black mode, a normally white mode may be used. Also, the liquid crystal panels 100R, 100G, and 100B are of a transmissive type, but may be of a reflective type.

[0067] (C-2: Variation 2) The display device 1 may include a light path shift element that shifts the position of a display pixel formed by light emitted from each of the liquid crystal panels 100R, 100G, and 100B for each unit period included in one frame, and may achieve high resolution by shifting the position of the display pixel for each unit period. For example, one frame is divided into four unit periods, and the light path shift element is used to shift the display position of the display pixel B1 to positions P1, P2, P3, and P4 as shown in FIG. 17, thereby achieving high resolution four times higher than the resolution of the liquid crystal panel 100. According to this embodiment, in a display device that achieves high resolution by shifting the position of the display pixel for each unit period, coloring of a display image caused by a difference between the transmittance of a reference panel pixel and the transmittance of each of two panel pixels other than the reference panel pixel can be suppressed.

[0068] (C-3: Variation 3) The correction LUT in the above embodiment is a two-dimensional lookup table that stores a correction value for the R subpixel on the black side and a correction value for each of the G and B subpixels on the white side in association with the gradation level of the R subpixel on the black side and the gradation level of the R subpixel on the white side. However, the correction LUT of the present disclosure may be a one-dimensional lookup table that stores a correction value for the R subpixel on the black side and a correction value for each of the G and B subpixels on the white side in association with the difference between the gradation level of the R subpixel on the black side and the gradation level of the R subpixel on the white side.

[0069] In addition, in the case of a display device that achieves high resolution by shifting the position of a display pixel every unit period as shown in Fig. 18(1), if display pixel B2 is a white pixel and display pixel B1 is a black pixel over one frame as shown in Fig. 18(2), color shift due to domains occurs at positions P5 and P6. In Fig. 18, W represents a white pixel and K represents a black pixel. On the other hand, as shown in Fig. 18(3), it is assumed that display pixel B2 is a white pixel over one frame, but display pixel B1 switches from a black pixel to a white pixel. In this case, a decrease in display quality due to liquid crystal response occurs at positions P3 and P4, and color shift due to domains occurs at positions P5 and P6. Even when a deterioration in display quality due to liquid crystal response and coloring due to domains occur in combination, the display device of the present disclosure can suppress the deterioration in display quality caused by the above-mentioned combination by setting the stored contents of the correction LUT so that the transmittance of each sub-pixel in each of the white-side pixels displayed at positions P3 to P8 is uniform.

[0070] D. Summary of the Disclosure The present disclosure is not limited to the above-mentioned embodiments and modifications, and can be realized in various aspects without departing from the spirit of the present disclosure. For example, the present disclosure can also be realized in the following aspects. The technical features in the above-mentioned embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined in order to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. The following is a summary of this disclosure.

[0071] (Appendix 1) A control method for a display device according to one embodiment of the present disclosure is a control method for a display device comprising a first liquid crystal panel, a second liquid crystal panel, and a third liquid crystal panel, and displaying an image based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel, the control method including: supplying pixel data of a first color to the first liquid crystal panel, supplying pixel data of a second color different from the pixel data of the first color to the second liquid crystal panel, and supplying pixel data of a third color different from the pixel data of the first color and the second color to the third liquid crystal panel; and determining a panel pixel having the lowest transmittance among a first panel pixel of the first liquid crystal panel corresponding to a first display pixel in the image, a second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and a third panel pixel corresponding to the first display pixel in the third liquid crystal panel as a reference panel pixel, and lowering a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel, other than the reference panel pixel, among the first panel pixel, the second panel pixel, and the third panel pixel.

[0072] According to the control method described in (Appendix 1), the gradation level of the pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel is lowered, thereby reducing the difference between the transmittance of the reference panel pixel and the transmittance of each of the two panel pixels other than the reference panel pixel, among the first panel pixel, the second panel pixel, and the third panel pixel, and suppressing coloring of the displayed image caused by variations in transmittance.

[0073] (Appendix 2) The control method of (Appendix 2) is the control method described in (Appendix 1), wherein the display device includes a light path shift element that shifts the position of a display pixel formed by the light emitted from each of the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each unit period included in one frame.

[0074] According to the control method described in (Appendix 2), in a display device that achieves high resolution by shifting the position of a display pixel every unit period, it is possible to suppress coloring of a displayed image caused by a difference between the transmittance of a reference panel pixel and the transmittance of each of two panel pixels other than the reference panel pixel.

[0075] (Appendix 3) The control method of (Appendix 3) is the control method described in (Appendix 1) or (Appendix 2), further including increasing the gradation level of pixel data supplied to panel pixels adjacent to the reference panel pixel, among a fourth panel pixel of the first liquid crystal panel corresponding to a second display pixel adjacent to the first display pixel in the image, a third panel pixel corresponding to the second display pixel in the second liquid crystal panel, and a sixth panel pixel corresponding to the second display pixel in the third liquid crystal panel.

[0076] According to the control method described in (Supplementary Note 3), by increasing the grayscale level of pixel data supplied to the fourth, fifth, and sixth panel pixels that are adjacent to the reference panel pixel, the horizontal electric field between the reference panel pixel and the panel pixel adjacent to the reference panel pixel is reduced, and the domain is suppressed. As a result of the suppression of the domain, the transmittance of the reference panel pixel is increased, and coloring is suppressed.

[0077] (Appendix 4) The control method of (Supplementary Note 4) is the control method according to (Supplementary Note 3), further comprising increasing the grayscale level of pixel data supplied to the reference panel pixel.

[0078] According to the control method described in (Appendix 4), the transmittance of the reference panel pixel increases as the gradation level of the pixel data supplied to the reference panel pixel is increased, thereby further reducing the difference between the transmittance of the reference panel pixel and the transmittance of each of the two panel pixels other than the reference panel pixel, among the first panel pixel, the second panel pixel, and the third panel pixel, and thus suppressing coloring of the displayed image caused by variations in transmittance.

[0079] (Appendix 5) The control method of (Appendix 5) is a control method described in (Appendix 4) further including lowering the gradation level of pixel data supplied to the fourth panel pixel, the fifth panel pixel, and the sixth panel pixel other than the reference panel pixel and the panel pixels adjacent to it.

[0080] According to the control method described in (Supplementary Note 5), by lowering the grayscale level of pixel data supplied to panel pixels other than the reference panel pixel and adjacent panel pixels, the horizontal electric field at the domain boundary is strengthened, and the transmittance of the fourth, fifth, and sixth panel pixels other than the reference panel pixel and adjacent panel pixels is reduced, thereby further reducing the variation in transmittance.

[0081] (Appendix 6) The control method of (Appendix 6) is a control method described in any one of (Appendix 1), (Appendix 2), (Appendix 3), or (Appendix 5), wherein the gradation level of the first display pixel is higher than the gradation level of the second display pixel.

[0082] According to the control method described in (Supplementary Note 6), it is possible to suppress a decrease in display quality caused by a difference between the grayscale level of the first display pixel and the grayscale level of the second display pixel.

[0083] (Appendix 7) A control method for a display device according to another embodiment of the present disclosure includes a first liquid crystal panel, a second liquid crystal panel, and a third liquid crystal panel, and displays an image based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel, and includes a correction lookup table storing correction data corresponding to a difference in gradation levels of two adjacent display pixels in the image, the control method including the steps of: acquiring the correction data from the correction lookup table based on pixel data representing the gradation levels of each color of the first display pixel in the image and pixel data representing the gradation level of a second display pixel adjacent to the first display pixel; the first panel pixel corresponding to the first display pixel in the first liquid crystal panel, the second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and the third panel pixel corresponding to the first display pixel in the third liquid crystal panel being a reference panel pixel; lowering a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel based on the correction data; and supplying pixel data in which the gradation levels of the two colors have been corrected based on the correction data to the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each color.

[0084] According to the control method described in (Appendix 7), the grayscale levels of the pixel data supplied to the first, second, and third panel pixels other than the reference panel pixel are lowered based on the correction data stored in the correction lookup table, thereby reducing the difference between the transmittance of the reference panel pixel and each of the first, second, and third panel pixels other than the reference panel pixel, and suppressing coloring of the displayed image caused by variations in transmittance.

[0085] (Appendix 8) A display device according to one aspect of the present disclosure includes a first liquid crystal panel, a second liquid crystal panel, a third liquid crystal panel, a storage device that stores a correction lookup table in which correction data corresponding to a difference in gradation levels of two adjacent display pixels in an image displayed based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel is stored, and a control device, wherein the control device acquires correction data from the correction lookup table based on pixel data representing the gradation levels of each color of a first display pixel in the image and pixel data representing the gradation level of a second display pixel adjacent to the first display pixel, the panel pixel having the lowest transmittance among a first panel pixel corresponding to the first display pixel in the panel, a second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and a third panel pixel corresponding to the first display pixel in the third liquid crystal panel is set as a reference panel pixel, and the gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel among the first panel pixel, the second panel pixel, and the third panel pixel is lowered based on the correction data, and pixel data in which the gradation levels of the two colors have been corrected based on the correction data are supplied to the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each color.

[0086] In the display device described in (Supplementary Note 8), the grayscale levels of the pixel data supplied to the first, second, and third panel pixels other than the reference panel pixel are lowered based on the correction data stored in the correction lookup table, thereby reducing the difference between the transmittance of the reference panel pixel and each of the first, second, and third panel pixels other than the reference panel pixel, and suppressing coloring of the displayed image caused by variations in transmittance. [Explanation of symbols]

[0087] 1...display device, 100R, 100G, 100B...liquid crystal panel, 110...sub-pixel circuit, 118...pixel electrode, 120...liquid crystal element, 200...image processing device, 210...display control circuit, 220R, 220R, 220G...processing circuit, 300...storage device.

Claims

1. A control method for a display device comprising a first liquid crystal panel, a second liquid crystal panel, and a third liquid crystal panel, the display device displaying an image based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel, the method comprising: supplying pixel data of a first color to the first liquid crystal panel, pixel data of a second color different from the pixel data of the first color to the second liquid crystal panel, and pixel data of a third color different from the pixel data of the first color and the second color to the third liquid crystal panel; and a panel pixel having the lowest transmittance among a first panel pixel of the first liquid crystal panel corresponding to a first display pixel in the image, a second panel pixel of the second liquid crystal panel corresponding to the first display pixel, and a third panel pixel of the third liquid crystal panel corresponding to the first display pixel, is set as a reference panel pixel, and the gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel is reduced; A method for controlling a display device comprising:

2. 2. The display device control method according to claim 1, wherein the display device comprises a light path shift element that shifts the position of a display pixel formed by light emitted from each of the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each unit period included in one frame.

3. 2. The display device control method according to claim 1, further comprising increasing a gradation level of pixel data supplied to panel pixels adjacent to the reference panel pixel, among a fourth panel pixel of the first liquid crystal panel corresponding to a second display pixel adjacent to the first display pixel in the image, a fifth panel pixel of the second liquid crystal panel corresponding to the second display pixel, and a sixth panel pixel of the third liquid crystal panel corresponding to the second display pixel.

4. 4. The method of claim 3, further comprising increasing the gray level of pixel data supplied to the reference panel pixel.

5. 5. The display device control method according to claim 4, further comprising lowering the grayscale level of pixel data supplied to the fourth panel pixel, the fifth panel pixel, and the sixth panel pixel other than the panel pixel adjacent to the reference panel pixel.

6. 2. The method of claim 1, wherein the gray level of the first display pixel is higher than the gray level of a second display pixel adjacent to the first display pixel in the image.

7. A control method for a display device comprising a first liquid crystal panel, a second liquid crystal panel, and a third liquid crystal panel, which displays an image based on light emitted from the first liquid crystal panel, light emitted from the second liquid crystal panel, and light emitted from the third liquid crystal panel, and which comprises a correction lookup table storing correction data corresponding to a difference in gradation levels between two adjacent display pixels in the image, acquiring correction data from the correction lookup table based on pixel data representing the gradation level of each color of a first display pixel in the image and pixel data representing the gradation level of a second display pixel adjacent to the first display pixel; a panel pixel having the lowest transmittance among a first panel pixel corresponding to the first display pixel in the first liquid crystal panel, a second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and a third panel pixel corresponding to the first display pixel in the third liquid crystal panel, is set as a reference panel pixel, and a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel is reduced based on the correction data; and supplying pixel data, the gradation levels of which have been corrected for two colors based on the correction data, to the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each color; A method for controlling a display device, comprising:

8. a first liquid crystal panel; a second liquid crystal panel; a third liquid crystal panel; a storage device that stores a correction lookup table that stores correction data corresponding to a difference in gradation levels between two adjacent display pixels in an image displayed based on the light emitted from the first liquid crystal panel, the light emitted from the second liquid crystal panel, and the light emitted from the third liquid crystal panel; a control device; The control device acquiring correction data from the correction lookup table based on pixel data representing the gradation level of each color of a first display pixel in the image and pixel data representing the gradation level of a second display pixel adjacent to the first display pixel; a panel pixel having the lowest transmittance among a first panel pixel corresponding to the first display pixel in the first liquid crystal panel, a second panel pixel corresponding to the first display pixel in the second liquid crystal panel, and a third panel pixel corresponding to the first display pixel in the third liquid crystal panel, is set as a reference panel pixel, and a gradation level of pixel data supplied to the first panel pixel, the second panel pixel, and the third panel pixel other than the reference panel pixel is reduced based on the correction data; and supplying pixel data, the gradation levels of which have been corrected for two colors based on the correction data, to the first liquid crystal panel, the second liquid crystal panel, and the third liquid crystal panel for each color; A display device that performs the above.

Images