Circuit devices and display systems

Abstract

To provide a circuit arrangement that can accurately determine the brightness of light reaching pixels from a backlight.SOLUTION: A circuit arrangement 100 includes: a storage unit 170 that stores a plurality of lookup tables; and a brightness information operation circuit 150 that operates brightness information indicating the brightness of light reaching a target pixel of a display panel 220 from a backlight 210. A first lookup table is associated with a first light source element provided at a first position and indicates a first attenuation factor distribution of the first light source element. A second lookup table is associated with a second light source element provided at a second position and indicates a second attenuation factor distribution of the second light source element. The brightness information operation circuit 150 determines a first attenuation factor of the light reaching the target pixel from the first light source element based on the first lookup table, determines a second attenuation factor of the light reaching the target pixel from the second light source element based on the second lookup table, and operates the brightness information based on the first attenuation factor and the second attenuation factor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to a circuit device and a display system, etc. [Background technology]

[0002] Patent Document 1 discloses an image display device that performs local dimming. The image display device includes an LED output value calculation unit, a display brightness data calculation unit, and an LDC data calculation unit. The LED output value calculation unit obtains emission brightness data that indicates the brightness of the light source corresponding to each area of ​​the image when it emits light. The display brightness data calculation unit obtains diffuse brightness data by applying a convolution process using a pre-prepared brightness diffusion function to the emission brightness data. The linear interpolation unit obtains display brightness data, which is data with a pixel-by-pixel value for each primary color, by performing a linear interpolation process on the diffuse brightness data. The LDC data calculation unit obtains the light transmittance for each pixel for each primary color based on the input image data and the display brightness data, and outputs data representing that light transmittance as LCD data. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-095559 [Overview of the project] [Problems that the invention aims to solve]

[0004] A backlight has multiple light sources, and the surrounding structure of each light source differs depending on its position. As a result, the diffusion pattern of light reaching the display panel from the light source differs depending on the surrounding structure. If the brightness of the light reaching each pixel of the display panel from the backlight is not taken into account, it becomes difficult to determine the brightness accurately. Since color correction of image data is performed based on the brightness of the light reaching each pixel, if the brightness is not determined accurately, appropriate color correction cannot be performed. Patent Document 1 neither discloses nor suggests considering the difference in the light diffusion pattern depending on the position of the light source when determining the brightness of the light reaching each pixel from the backlight. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to a circuit device in which each lookup table includes a storage unit that stores a plurality of lookup tables showing the attenuation rate distribution of light source elements of the backlight of a display device having a display panel and a backlight, and a brightness information calculation circuit that calculates brightness information showing the brightness of light reaching a target pixel of the display panel from the backlight, wherein the storage unit stores as the plurality of lookup tables a first lookup table associated with a first light source element provided at a first position of the backlight and showing a first attenuation rate distribution of the first light source element, and a second lookup table associated with a second light source element provided at a second position different from the first position of the backlight and showing a second attenuation rate distribution of the second light source element, and the brightness information calculation circuit relates to a circuit device that determines a first attenuation rate of light reaching the target pixel from the first light source element based on the first lookup table, determines a second attenuation rate of light reaching the target pixel from the second light source element based on the second lookup table, and calculates the brightness information based on the first attenuation rate and the second attenuation rate.

[0006] Another aspect of this disclosure relates to a display system including the above-described circuit device and the display device. [Brief explanation of the drawing]

[0007] [Figure 1] Configuration example of an electronic device including the display system of this embodiment. [Figure 2] Detailed configuration example of a circuit device. [Figure 3] Flowchart of the processing performed by the luminance information calculation circuit. [Figure 4] Diagram explaining the difference in the attenuation rate distribution according to the position of the light source element. [Figure 5] Diagram explaining the anisotropic attenuation rate distribution. [Figure 6] Example of a lookup table corresponding to a light source element far from the side and corner portions. [Figure 7] Example of a lookup table corresponding to a light source element arranged along the side. [Figure 8] Example of a lookup table corresponding to a light source element arranged at the corner portion. [Figure 9] Diagram explaining the rotation of the lookup table corresponding to a light source element arranged along the side. [Figure 10] Diagram explaining the rotation of the lookup table corresponding to a light source element arranged at the corner portion. [Figure 11] Explanatory diagram of a method for determining a light source element used in luminance calculation. [Figure 12] Diagram explaining the distance between a target pixel and each light source element in a group of light source elements. [Figure 13] Diagram explaining the calculation method of linear interpolation. [Figure 14] Diagram explaining a specific calculation example of linear interpolation.

Mode for Carrying Out the Invention

[0008] Hereinafter, preferred embodiments of the present disclosure will be described in detail. Note that the embodiments described below do not unduly limit the content described in the claims, and not all of the configurations described in the embodiments are essential constituent elements.

[0009] 1. Electronic Device, Display System, and Circuit Device Figure 1 shows an example of the configuration of an electronic device including a display system according to this embodiment. The electronic device 500 includes a processing unit 300 and a display system 400. Examples of the electronic device 500 include an in-vehicle cluster panel including a display, an in-vehicle display device including a head-up display, a television system, or an information processing device including a display.

[0010] The display system 400 includes a circuit device 100 and a display device 200. The circuit device 100 is, for example, an integrated circuit device in which multiple circuit elements are integrated on a semiconductor substrate. Although the circuit device 100 and the display device 200 are shown as separate components in Figure 1, the circuit device 100 may be included within the display device 200.

[0011] The display device 200 includes a backlight 210, a display panel 220, a display driver 230, a light source driver 240, and a display controller 250. An example of the display device 200 is a display used in a television system or an information processing device. Alternatively, the display device 200 may be a head-mounted display including a projection device for the eye, or a head-up display including a projection device for a screen. When the display device 200 is a head-up display, the display device 200 further includes an optical system for projecting light emitted from the backlight 210 and transmitted through the display panel 220 onto a screen.

[0012] In a plan view of the backlight 210, the backlight 210 has light source elements arranged in two dimensions. The light source elements are light-emitting elements that emit light when power is supplied, such as inorganic light-emitting diodes or organic light-emitting diodes. In local dimming control, the light intensity of each of the two-dimensionally arranged light source elements is controlled independently of each other. Alternatively, the backlight may be divided into multiple areas in a plan view, each area containing multiple light source elements, and the light source elements in each area may be controlled to the same light intensity, while the light intensity of each area may be controlled independently of each other.

[0013] One example of a two-dimensional arrangement of light sources is a square arrangement in which light sources are placed at all intersections of multiple rows and multiple columns. However, the two-dimensional arrangement is not limited to a square arrangement. For example, the two-dimensional arrangement may be an arrangement called a rhombus arrangement or a staggered arrangement. In this arrangement, light sources are placed at the intersections of one odd-numbered row and one even-numbered row with an odd-numbered column, and at the intersections of the other odd-numbered row and one even-numbered row with an even-numbered column, while no light sources are placed at any other intersections.

[0014] The light source driver 240 receives dimming data DDIM from the circuit device 100 and drives each light source element of the backlight 210 based on the dimming data DDIM. The light source driver 240 is, for example, an integrated circuit device. Alternatively, multiple light source drivers may be provided, each of which may be a separate integrated circuit device.

[0015] The display panel 220 is an electro-optical panel that transmits light from the backlight 210 and displays an image by controlling the transmittance of that light. For example, the display panel 220 is a liquid crystal display panel.

[0016] The display controller 250 receives image data IMB from the circuit device 100 and transmits the image data IMB and a timing control signal for controlling the display timing to the display driver 230. The display controller 250 may also perform image processing such as gradation correction, white balance correction, or scaling on the received image data IMB.

[0017] The display driver 230 drives the display panel based on the received image data and timing control signals to display an image on the display panel 220. The display controller 250 and the display driver 230 may each be composed of separate integrated circuit devices, or they may be composed of a single integrated circuit device.

[0018] The processing unit 300 transmits image data (IMA) to the circuit device 100. The processing unit 300 is a processor such as a CPU, microcomputer, DSP, ASIC, or FPGA.

[0019] The circuit device 100 receives the image data IMA and performs local dimming control of the display device 200 based on the image data IMA. The circuit device 100 determines the luminance of each light source element or area of ​​the backlight 210 as dimming information by performing a luminance analysis on the image data IMA, and outputs dimming data DDIM indicating this dimming information to the light source driver 240. The circuit device 100 also performs color correction on the image data IMA based on the dimming information and outputs the color-corrected image data IMB to the display controller 250.

[0020] Figure 2 shows a detailed example of the circuit device configuration. The circuit device 100 includes an interface circuit 110, a light source control circuit 130, a brightness analysis circuit 140, a brightness information calculation circuit 150, a color correction circuit 160, and a storage unit 170. The following explanation will use the case where each light-emitting element of the backlight 210 is dimmed independently in local dimming as an example, but each area containing multiple light-emitting elements may be dimmed independently.

[0021] The interface circuit 110 receives image data (IMA) from the processing unit 300. The interface circuit 110 may be an interface circuit using various image interface methods such as LVDS, parallel RGB, or DisplayPort.

[0022] The luminance analysis circuit 140 includes an image analysis unit 141 and a light source luminance determination unit 142. The image analysis unit 141 analyzes the luminance of the image data IMB. The light source luminance determination unit 142 determines the luminance of each light-emitting element based on the results of the analysis by the image analysis unit 141 and outputs dimming data LLD indicating the luminance of each light-emitting element as dimming information. For example, the image analysis unit 141 determines the maximum luminance of the pixel data belonging to the image area corresponding to the light-emitting elements of the backlight 210. The light source luminance determination unit 142 determines the minimum luminance within the range that can be displayed on the display device 200, and sets that as the luminance of the light-emitting element.

[0023] The light source control circuit 130 outputs dimming data DDIM, which indicates the luminous intensity of each light source element, to the light source driver 240 based on dimming data LLD, which indicates the luminous intensity of each light source element. The light source driver 240 drives each light-emitting element with a PWM signal with a pulse width corresponding to the luminous intensity of each light source element indicated by the dimming data DDIM. As a result, each light-emitting element emits light at a luminous intensity controlled by local dimming.

[0024] The memory unit 170 stores a lookup table showing the attenuation rate distribution of light reaching the display panel from the light source element. Figure 2 shows an example in which the memory unit 170 stores three types of lookup tables, LUTA, LUTB, and LUTC, each with a different attenuation rate distribution. However, the number of lookup tables does not need to be more than two. The attenuation rate distribution shows the relationship between the distance from the light source element to the pixel and the attenuation rate of light reaching the pixel from the light source element. The attenuation rate distribution is also called the attenuation characteristic or luminance distribution. The memory unit 170 may be a register, or it may be a memory such as RAM or non-volatile memory.

[0025] The luminance information calculation circuit 150 includes a coordinate analysis unit 151 and a luminance calculation unit 152. Details will be explained in Figure 3 and later, but here we will give an overview. The coordinate analysis unit 151 determines which of the lookup tables LUTA, LUTB, or LUTC to use based on the coordinates of the light source element. The luminance calculation unit 152 obtains luminance information indicating the luminance of the light reaching each pixel of the display panel 220 from the light source element based on the lookup table determined by the coordinate analysis unit 151 and the dimming data LLD, and outputs this luminance information as illumination luminance data LPX.

[0026] The color correction circuit 160 performs color correction on the image data IMA based on the illumination luminance data LPX and outputs the corrected image data IMB to the display driver 230. Specifically, the color correction circuit 160 multiplies the pixel data of each pixel by the reciprocal of the luminance of the light reaching that pixel, and uses the result as the new pixel data for that pixel.

[0027] The light source control circuit 130, the luminance analysis circuit 140, the luminance information calculation circuit 150, and the color correction circuit 160 are logic circuits that process digital signals. Each of the light source control circuit 130, the luminance analysis circuit 140, the luminance information calculation circuit 150, and the color correction circuit 160 may be composed of a separate logic circuit, or some or all of them may be composed of a single logic circuit. Alternatively, a processor such as a DSP may implement the functions of the light source control circuit 130, the luminance analysis circuit 140, the luminance information calculation circuit 150, and the color correction circuit 160 by executing an instruction set or program that describes the functions of these circuits.

[0028] The circuit device 100 may also include a distortion correction circuit. The distortion correction circuit corrects image distortion caused by the optical system that projects the image displayed on the display panel 220 onto a screen or the like, or by distortion of the screen. Specifically, the distortion correction circuit performs image correction on the image data IMA received by the interface circuit 110 to cancel or reduce the above-mentioned image distortion, and outputs the corrected image data to the luminance analysis circuit 140, the luminance information calculation circuit 150, and the color correction circuit 160. However, the distortion correction circuit may be provided in the processing unit 300 instead of the circuit device 100.

[0029] 2. Processing flow of the brightness information calculation circuit Figure 3 is a flowchart of the processing performed by the brightness information calculation circuit. In the following, "target pixel" refers to the pixel for which brightness information is to be calculated.

[0030] In step S1, the coordinate analysis unit 151 determines the light source elements to be used for brightness calculation based on the coordinates of the target pixel. For example, as will be described later in Figure 11, the coordinate analysis unit 151 determines a predetermined number of light source elements arranged around the target pixel to be used for brightness calculation.

[0031] In step S2, the coordinate analysis unit 151 determines, for each light source element determined in step S1, the lookup table to reference and its rotation angle based on the position of that light source element. For example, as will be described later in Figures 4 to 10, the coordinate analysis unit 151 determines which of the lookup tables LUTA, LUTB, or LUTC to reference, and whether the rotation angle should be 0°, 90°, 180°, or 270°.

[0032] In step S3, the luminance calculation unit 152 obtains the attenuation rate by referring to the lookup table determined in step S2 based on the distance between the coordinates of the target pixel and the light source element, and then calculates the attenuation rate at the target pixel by linear interpolation of the attenuation rate. Specifically, as will be described later in Figures 13 and 14, the luminance calculation unit 152 obtains four attenuation rates near the above distance from the lookup table and performs linear interpolation from these four attenuation rates.

[0033] In step S4, the luminance calculation unit 152 determines the luminance of the light reaching the target pixel from the light source element based on the luminance of each light source element dimmed by the light source luminance determination unit 142 and the attenuation rate determined in step S3. Steps S2 to S4 are performed for all light source elements determined in step S1.

[0034] In step S5, the luminance calculation unit 152 calculates the luminance of the light reaching the target pixel from the backlight 210 by adding the luminance obtained in step S4 for all the determined light source elements. For example, an example of luminance calculation is shown in equation (1) below, which will be described later, and four terms are added on the left side. Calculating each term corresponds to step S4, and adding the four terms corresponds to step S5.

[0035] 3. Details of Step S2 The details of each step will be explained below. First, the details of step S2 will be explained using Figures 4 to 10.

[0036] Figure 4 illustrates the differences in attenuation rate distribution depending on the position of the light source element. Figure 4 schematically shows the attenuation rate distribution mainly to illustrate the symmetry and does not represent the exact attenuation rate distribution.

[0037] In Figure 4, the three mutually orthogonal directions are defined as the x, y, and z directions. The backlight 210 and display panel 220 are arranged parallel to the xy plane, and the backlight 210 is located on the z-direction side of the display panel 220. The x direction is the horizontal direction of the display panel 220, and the y direction is the vertical direction of the display panel 220. Here, we show an example in which multiple light source elements 10 are arranged in a square on the backlight 210.

[0038] EDA to EDD are the four edges of the display panel 220. Edges EDA and EDC are opposite each other, and edges EDB and EDD are opposite each other. Note that the edges of the display panel 220 can be rephrased as the edges of the backlight 210. CNA is the corner where edges EDA and EDB intersect, CNB is the corner where edges EDB and EDC intersect, CNC is the corner where edges EDC and EDB intersect, and CND is the corner where edges EDD and EDA intersect. The corners CNA to CND are also called corners or vertices. Note that the corners of the display panel 220 can be rephrased as the corners of the backlight 210.

[0039] The attenuation rate distribution (DFPA) of light source elements away from edges and corners is an isotropic distribution. That is, the attenuation rate distribution (DFPA) is rotationally symmetric with respect to the light source element, meaning that the attenuation characteristics are independent of direction with respect to the light source element. "Away from edges and corners" means that in a square arrangement, at least one row or one column is away from the edges and corners.

[0040] The attenuation rate distribution DFPB of light source elements positioned along side EDA and away from corners CNA and CND is anisotropic. Side EDA is parallel to the y-direction. In this case, the attenuation rate distribution DFPB is symmetric with respect to a line passing through the center of the attenuation rate distribution DFPB and parallel to the x-direction, and non-symmetric with respect to a line passing through the center of the attenuation rate distribution DFPB and parallel to the y-direction.

[0041] The attenuation rate distribution DFPC of the light source elements positioned in the corner CNC is an anisotropic distribution. The attenuation rate distribution DFPC is non-symmetric with respect to a line passing through the center of the attenuation rate distribution DFPB and parallel to the x-direction, and is also non-symmetric with respect to a line passing through the center of the attenuation rate distribution DFPB and parallel to the y-direction.

[0042] Figure 5 illustrates an anisotropic attenuation rate distribution. The display device 200 includes a structure 270 arranged around the backlight 210 and the display panel 220. The structure 270 is, for example, a light-shielding member, which houses the backlight 210 and the display panel 220 and also shields the light from leaking from the backlight 210 to the display panel 220. A portion of the light emitted from the light source element 10 near the edge or corner of the backlight 210 is reflected by the structure 270, and this reflected light reaches the display panel 220. In these regions AR1 and AR2, the direct light from the light source element 10 and the reflected light from the structure 270 overlap, resulting in an increase in light intensity compared to the case without reflected light. This causes anisotropy, as seen in the attenuation rate distributions DFPB and DFPC in Figure 4.

[0043] Figure 6 shows an example of a lookup table LUTA corresponding to light source elements far from the edges and corners. u is the distance between the light source element and the target pixel in the x-direction. v is the distance between the light source element and the target pixel in the y-direction. Below, we show an example where the inputs to the lookup table are u2 and v2, but the inputs to the lookup table are not limited to this; for example, they could be u and v.

[0044] The center of the attenuation rate distribution is u=v=0. The direction DA, where u increases from the center, corresponds to the direction from the center towards edge EDA. The direction DC, where u decreases from the center, corresponds to the direction from the center towards edge EDC. The direction DD, where v increases from the center, corresponds to the direction from the center towards edge EDD. The direction DB, where v decreases from the center, corresponds to the direction from the center towards edge EDB. In the lookup table LUTA, the attenuation characteristics are the same in all directions from the center towards any edge. That is, the attenuation rate distribution of the lookup table LUTA is rotationally symmetric with respect to its center.

[0045] Figure 7 shows an example of a lookup table LUTB corresponding to light source elements arranged along an edge. In Figure 7, the differences between the lookup table LUTB and LUTA are indicated by hatching.

[0046] In the lookup table LUTB, the attenuation characteristics in the direction DA from the center toward edge EDA are different from the attenuation characteristics in the directions DB, DC, and DD from the center toward edges EDB, EDC, and EDD. The attenuation characteristics in the directions DB, DC, and DD from the center toward edges EDB, EDC, and EDD are the same. That is, the attenuation rate distribution of the lookup table LUTB is not rotationally symmetric with respect to its center. Furthermore, the attenuation rate distribution of the lookup table LUTB is line-symmetric with respect to a line passing through its center and parallel to direction DA, and is not line-symmetric with respect to a line passing through its center and parallel to direction DD.

[0047] Figure 8 shows an example of a lookup table LUTC corresponding to a light source element located in the corner. In Figure 8, the differences between the lookup table LUTC and LUTA are indicated by hatching.

[0048] In the lookup table LUTC, the attenuation characteristics in the direction DD from the center toward edge EDD are different from those in the direction DB from the center toward edge EDB, and the attenuation characteristics in the direction DC from the center toward edge EC are different from those in the direction DA from the center toward edge EDA. The attenuation characteristics in the directions DC and DD from the center toward edges EDC and EDD are the same, and the attenuation characteristics in the directions DA and DB from the center toward edges EDA and EDB are the same. That is, the attenuation rate distribution of the lookup table LUTC is not rotationally symmetric with respect to its center. Furthermore, the attenuation rate distribution of the lookup table LUTC is not linearly symmetric with respect to a line passing through its center and parallel to direction DC, and is not linearly symmetric with respect to a line passing through its center and parallel to direction DD.

[0049] Figure 9 illustrates the rotation of the lookup table LUTB corresponding to the light source elements arranged along the edges.

[0050] As shown in Figure 9, the attenuation rate distribution of light source elements arranged along sides EDB, EDC, and EDD is obtained by rotating the attenuation rate distribution DFPB of light source elements arranged along side EDA by 90°, 180°, and 270° counterclockwise. The coordinate analysis unit 151 determines the reference lookup table and its rotation angle as follows.

[0051] The coordinate analysis unit 151 determines the reference lookup table to lookup table LUTB and sets the rotation angle to 0° for light source elements arranged along edge EDA. Similarly, the coordinate analysis unit 151 determines the reference lookup table to lookup table LUTB and sets the rotation angles to 90°, 180°, and 270° for light source elements arranged along edges EDB, EDC, and EDD. The brightness calculation unit 152 refers to the reference lookup table rotated counterclockwise by the rotation angles determined above to determine the attenuation rate of the target pixel.

[0052] Figure 10 illustrates the rotation of the lookup table LUTC corresponding to the light source element located in the corner.

[0053] As shown in Figure 10, the attenuation rate distribution of the light source elements located in corner sections CND, CNA, and CNB is obtained by rotating the attenuation rate distribution DFPC of the light source elements located in corner section CNC by 90°, 180°, and 270° counterclockwise. Based on this, the coordinate analysis unit 151 determines the reference lookup table and its rotation angle as follows.

[0054] The coordinate analysis unit 151 determines the reference lookup table to lookup table LUTC and sets the rotation angle to 0° for the light source elements located at corner CNC. Similarly, the coordinate analysis unit 151 determines the reference lookup table to lookup table LUTC and sets the rotation angles to 90°, 180°, and 270° for the light source elements located at corner CND, CNA, and CNB. The brightness calculation unit 152 calculates the attenuation rate of the target pixel by referring to the reference lookup table rotated counterclockwise by the rotation angles determined above.

[0055] Note that while Figures 9 and 10 show examples of rotating the lookup table counterclockwise, it may also be rotated clockwise. Clockwise rotation angles of 0°, 90°, 180°, and 270° correspond to counterclockwise rotation angles of 0°, 270°, 180°, and 90°, respectively.

[0056] In this embodiment described above, the circuit device 100 includes a storage unit 170 that stores a plurality of lookup tables, and a brightness information calculation circuit 150 that calculates brightness information indicating the brightness of light reaching a target pixel of the display panel 220 from the backlight 210. Each of the plurality of lookup tables shows the attenuation rate distribution of the light source elements of the backlight 210 of a display device 200 having a display panel 220 and a backlight 210. The storage unit 170 stores a first lookup table and a second lookup table. The first lookup table is associated with a first light source element provided at a first position of the backlight 210 and shows the first attenuation rate distribution of the first light source element. The second lookup table is associated with a second light source element provided at a second position different from the first position of the backlight 210 and shows the second attenuation rate distribution of the second light source element. The luminance information calculation circuit 150 determines the first attenuation rate of light reaching the target pixel from the first light source element based on the first lookup table, and determines the second attenuation rate of light reaching the target pixel from the second light source element based on the second lookup table. The luminance information calculation circuit 150 calculates luminance information based on the first and second attenuation rates.

[0057] Note that the first lookup table here may be any of the lookup tables LUTA, LUTB, and LUTC. The second lookup table here may be any lookup table from LUTA, LUTB, and LUTC that is different from the first lookup table.

[0058] According to this embodiment, a first lookup table is associated with a first light source element located at a first position, and a second lookup table is associated with a second light source element located at a second position different from the first position. This allows for the application of lookup tables with different attenuation rate distributions depending on the position of the light source element, making it possible to accurately determine the brightness of the light reaching each pixel from the backlight, taking into account the differences in light diffusion patterns depending on the position of the light source element. Since the brightness of the light reaching each pixel from the backlight can be accurately determined, the image data can be appropriately color-corrected.

[0059] In this embodiment, each lookup table is a table that associates the attenuation rate at a given distance from a light source element to a pixel on the display panel 220. The luminance information calculation circuit 150 determines the first attenuation rate at a given distance from the first light source element to the target pixel based on the first lookup table. The luminance information calculation circuit 150 determines the second attenuation rate at a given distance from the second light source element to the target pixel based on the second lookup table.

[0060] In the examples in Figures 6 to 8, the distance from the light source element to the target pixel is the square of the horizontal distance u and the square of the vertical distance v, but is not limited to this. For example, the distance from the light source element to the target pixel may be the horizontal distance u and the vertical distance v, or it may be the straight-line distance from the light source element to the target pixel and the angle between that line and the reference direction. The reference direction may be, for example, the x-direction or the y-direction.

[0061] According to this embodiment, the first attenuation rate at the distance from the first light source element to the target pixel is determined based on the first lookup table, and the second attenuation rate at the distance from the second light source element to the target pixel is determined based on the second lookup table. This makes it possible to determine the attenuation rate at the distance from the light source element to the target pixel based on lookup tables with different attenuation rate distributions depending on the position of the light source element.

[0062] In this embodiment, the second position is closer to the first side of the display panel 220 compared to the first position.

[0063] The first position here corresponds to the position of the light source element away from the edges and corners, corresponding to the attenuation rate distribution DFPA in Figure 4. The second position here corresponds to the position of the light source element located along the edge and away from the corners, corresponding to the attenuation rate distribution DFPB in Figure 4. That is, the first lookup table here is LUTA, and the second lookup table is LUTB. Note that the first edge is edge EDA in Figure 4, but is not limited to this and may be any of the four edges of the display panel 220.

[0064] As explained in Figure 5, the attenuation rate distribution of light source elements positioned near the edges of the display panel 220 is affected by reflected light from the surrounding structures 270, and therefore differs from the attenuation rate distribution of light source elements positioned far from the edges of the display panel 220. According to this embodiment, the brightness of the light reaching each pixel from the backlight can be accurately determined by taking into account these differences in attenuation rate distribution.

[0065] In this embodiment, the backlight 210 also includes a third light source element. The third light source element is located in a third position, closer to the third side of the display panel 220 opposite the first side, compared to the first position. The luminance information calculation circuit 150 calculates the third attenuation rate of the light reaching the target pixel from the third light source element based on a lookup table obtained by rotating the second lookup table by 180 degrees. The luminance information calculation circuit 150 calculates luminance information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

[0066] Here, the third side is side EDC, which is opposite side EDA in Figures 4 and 9. The third position here is the position of the light source element that is positioned along side EDC and away from the corners at both ends of side EDC. As explained in Figure 9, by rotating the lookup table LUTB of the light source elements positioned along side EDA by 180 degrees, a lookup table of the light source elements positioned along side EDC can be obtained.

[0067] According to this embodiment, a lookup table of light source elements located near one side can be stored in the storage unit 170, and by rotating this lookup table, lookup tables for elements located near the other three sides can be generated. This saves storage capacity in the storage unit 170. However, a lookup table of light source elements located near each of the four sides may also be stored in the storage unit 170.

[0068] In this embodiment, the second position may be closer to the first corner where the first and second sides of the display panel 220 intersect, compared to the first position.

[0069] The first position here corresponds to the position of the light source element away from the edges and corners, corresponding to the attenuation rate distribution DFPA in Figure 4. The first edge here is edge EDC, the second edge is edge EDD, and the second position corresponds to the position of the light source element located at corner CNC, corresponding to the attenuation rate distribution DFPC in Figure 4. That is, the first lookup table here is LUTA, and the second lookup table is LUTC. Note that the first corner is corner CNC in Figure 4, but is not limited to this and may be any of the four corners of the display panel 220.

[0070] As explained in Figure 5, the attenuation rate distribution of a light source element located near the corner of the display panel 220 is affected by reflected light from the surrounding structure 270, and therefore differs from the attenuation rate distribution of a light source element located far from the corner of the display panel 220. According to this embodiment, the brightness of the light reaching each pixel from the backlight can be accurately determined by taking into account these differences in attenuation rate distribution.

[0071] In this embodiment, the backlight 210 also includes a third light source element. The third light source element is positioned closer to the second corner where the third side opposite the first side of the display panel 220 intersects with the fourth side opposite the second side, compared to the first position. The luminance information calculation circuit 150 calculates the third attenuation rate of the light reaching the target pixel from the third light source element based on a lookup table obtained by rotating the second lookup table by 180 degrees. The luminance information calculation circuit 150 calculates luminance information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

[0072] Here, the third side is side EDA opposite side EDC in Figures 4 and 10, the fourth side is side EDB opposite side EDD, and the third position is the position of the light source element located in the corner CNA. As explained in Figure 10, the lookup table LUTC of the light source element located in the corner CNC is obtained by rotating it 180 degrees.

[0073] According to this embodiment, a lookup table for a light source element located near one corner can be stored in the storage unit 170, and by rotating this lookup table, lookup tables for elements located near the other three corners can be generated. This saves storage capacity in the storage unit 170. However, a lookup table for a light source element located near each of the four corners may also be stored in the storage unit 170.

[0074] In this embodiment, the first attenuation rate distribution is rotationally symmetric with respect to the center. The second attenuation rate distribution is not rotationally symmetric with respect to the center.

[0075] Note that the first attenuation rate distribution here corresponds to the attenuation rate distribution DFPA in Figure 4. The second attenuation rate distribution here may be any of the attenuation rate distributions DFPB and DFPC in Figure 4.

[0076] The attenuation rate distribution of light source elements positioned far from the edges or corners of the display panel 220 is less affected by reflected light from the backlight 210 or the structures 270 surrounding the display panel 220. Therefore, the attenuation rate distribution of these light sources is rotationally symmetric, or can be approximated by a rotationally symmetric attenuation rate distribution. On the other hand, the attenuation rate distribution of light source elements positioned close to the edges or corners of the display panel 220 is affected by reflected light from the structures 270 surrounding them. Therefore, the attenuation rate distribution of these light sources is not rotationally symmetric, or can be approximated by a rotationally symmetric attenuation rate distribution.

[0077] Furthermore, in this embodiment, the second attenuation rate distribution has different attenuation characteristics in the direction from the center toward one side of the display panel 220 and in the direction from the center toward a side other than that side of the display panel 220.

[0078] For example, when the second attenuation rate distribution is the attenuation rate distribution DFPB in Figure 4, "one side" is side EDA, and "another side" is any side among sides EDB, EDC, and EDD. Alternatively, when the second attenuation rate distribution is the attenuation rate distribution DFPC in Figure 4, "one side" is any side among sides EDC and EDD, and "another side" is any side among sides EDA and EDB.

[0079] Reflected light from the structure 270 surrounding the backlight 210 or display panel 220 affects the region of the attenuation rate distribution that is close to the edges. As a result, the attenuation characteristics in the direction toward the edges that are not affected by the reflected light from the structure 270 are different from the attenuation characteristics in the direction toward the edges that are affected by the reflected light from the structure 270.

[0080] In this embodiment, the memory unit 170 stores a third lookup table. The third lookup table is associated with a third light source element located at a third position different from the first and second positions of the backlight 210, and shows the third attenuation rate distribution of the third light source element. The second position is closer to the first side of the display panel 220 compared to the first position. The third position is closer to the first corner where the second and third sides of the display panel intersect, compared to the first position. The luminance information calculation circuit 150 determines the third attenuation rate of the light reaching the target pixel from the third light source element based on the third lookup table, and calculates luminance information based on the first attenuation rate, second attenuation rate, and third attenuation rate.

[0081] The first position here corresponds to the position of the light source element away from the edges and corners, corresponding to the attenuation rate distribution DFPA in Figure 4. The second position here corresponds to the position of the light source element along the edge and away from the corners, corresponding to the attenuation rate distribution DFPB in Figure 4. The third position here corresponds to the position of the light source element located at the corner CNC, corresponding to the attenuation rate distribution DFPC in Figure 4. The first edge, second edge, and third edge correspond to edges EDA, EDC, and EDD, respectively, and the first corner corresponds to the corner CNC. However, the first edge may be any edge from EDA to EDD, and the first corner may be any of the corners CNA to CND.

[0082] According to this embodiment, the first to third lookup tables are associated with the first to third light source elements, which are located at different first to third positions. This allows the application of lookup tables with different attenuation rate distributions depending on the position of the light source elements, making it possible to accurately determine the brightness of the light reaching each pixel from the backlight, taking into account the differences in light diffusion patterns depending on the position of the light source elements.

[0083] In this embodiment, the circuit device 100 also includes a luminance analysis circuit 140 and a color correction circuit 160. The luminance analysis circuit 140 performs a luminance analysis of the image data IMA and determines dimming information for local dimming control based on the results of the luminance analysis. The luminance information calculation circuit 150 determines the first luminance of the light reaching the target pixel from the first light source element based on the dimming information and the first attenuation rate, and determines the second luminance of the light reaching the target pixel from the second light source element based on the dimming information and the second attenuation rate. The luminance information calculation circuit 150 calculates luminance information indicating the luminance of the light reaching the target pixel from the backlight 210 based on the first and second luminances. The color correction circuit 160 performs color correction of the image data of the target pixel based on the luminance information and outputs the color-corrected image data IMB to the display device 200.

[0084] According to this embodiment, the first brightness of the light reaching the target pixel from the first light source element and the second brightness of the light reaching the target pixel from the second light source element can be accurately determined by taking into account the difference in light diffusion patterns depending on the position of the light source element. As a result, brightness information indicating the brightness of the light reaching the target pixel from the backlight 210 can be accurately determined, so that the color correction circuit 160 can appropriately color correct the image data of the target pixel based on the brightness information.

[0085] 4. Details of Steps S1, S4, and S5 Steps S1, S4, and S5 will be explained in detail using Figures 11 and 12. Figure 11 is an explanatory diagram of the method for determining the light source element used in luminance calculation.

[0086] The luminance information calculation circuit 150 designates the pixel for which it seeks luminance information as the target pixel 20, and its x and y coordinates are denoted as (xP, yP). The luminance information calculation circuit 150 obtains the luminance information for each pixel of the display panel 220 by sequentially shifting the target pixel 20 and obtaining the luminance information.

[0087] Let the x and y coordinates of the light source element 10 be (xL, yL). When viewing the display panel 220 and backlight 210 in a plan view in the z direction, the coordinates on the display panel 220 corresponding to the reference point of each light source element are (xL, yL). The reference point is the center of the light source element or the point with the highest brightness in the plan view.

[0088] The coordinate analysis unit 151 selects a plurality of light source elements 10 arranged around the target pixel 20. The selected plurality of light source elements 10 are called the light source element group 15. Figure 11 shows an example in which four light source elements are selected around the target pixel 20. However, any number of light source elements arranged around the target pixel 20 may be selected, or all of the light source elements of the backlight 210 may be selected.

[0089] Figure 12 illustrates the distance between the target pixel and each light source element in the light source element group. The light source element in the i-th row and j-th column of the 2x2 light source elements belonging to the light source element group 15 is denoted as LDij. The xy coordinates of light source element LDij are denoted as (xLj, yLi), where i and j are integers between 1 and 2 (inclusive).

[0090] The distance is the distance on the xy plane or on the display panel 220. The distance may be an actual distance such as a meter, or it may be a distance defined in a predetermined unit. For example, if the predetermined unit is the pixel pitch of the display panel 220, the distance is indicated by the number of pixels on the display panel 220.

[0091] The coordinate analysis unit 151 determines the distances u1 and u2 between the light source element and the target pixel 20 in the x-direction, and the distances v1 and v2 between the light source element and the target pixel 20 in the y-direction. uj is the distance between the j-th column light source element and the target pixel 20 in the horizontal direction. Specifically, uj = xLj - xP. vi is the distance between the i-th row light source element and the target pixel 20 in the vertical direction. Specifically, vi = yLi - yP.

[0092] The luminance calculation unit 152 calculates the luminance PIX_BL of the light reaching the target pixel 20 from multiple light source elements belonging to the light source element group 15 using the following equation (1). LED_BLij is the luminous emission luminance of the light source element LDij determined by the light source luminance determination unit 142. LUT_LDij(uj 2 ,vi 2 ) is the attenuation rate of light reaching the target pixel 20 from the light source element LDij, and is the attenuation rate calculated by linear interpolation in step S3.

[0093]

number

[0094] 5. Details of Step S3 Step S3 will be explained in detail using Figures 13 and 14. Figure 13 is a diagram illustrating the calculation method of linear interpolation. Here, the brightness of light reaching the target pixel 20 from the light source element LD22 is used as an example, but the same applies to the brightness of light reaching the target pixel 20 from the light source elements LD11, LD12, and LD21. Hereafter, the distance in the x direction is denoted as u and the distance in the y direction as v, as shown by (u,v).

[0095] The distance between the light source element LD22 and the target pixel 20 is (u2,v2). The luminance calculation unit 152 selects the four nearest points (ua,va), (ub,va), (ua,vb), and (ub,vb) that contain (u2,v2) from the discrete distances used in the lookup table, and obtains their attenuation rates Luava, Lubva, Luavb, and Lubvb. The luminance calculation unit 152 performs horizontal linear interpolation using equation (2) below, and then uses the result to perform vertical linear interpolation using equation (3) below. The result of this linear interpolation is the attenuation rate of the light reaching the target pixel 20 from the light source element LD22 LUT_LD22(u2 2 ,v2 2 )

[0096]

number

[0097] [Numbers]

[0098] In the above equation (2), in the fractional part of the first term on the right side, the denominator is ub 2 -ua 2 It has become like this. When n is an integer greater than or equal to 1, ub 2 [[ID= (15)]]-ua 2 =2 n By using the distance that becomes like this in the look-up table, the operation of the fractional part becomes a bit shift in the LSB direction, and the operation load is reduced. For example, in the look-up tables of FIGS. 6 to 8, u 2 =0, 32, 64, 96, 128 are used, and ub 2 -ua 2 =32 = 2 5 It is. The same can be said for the fractional part of the first term in the middle of the above equation (3).

[0099] FIG. 14 is a diagram for explaining a specific calculation example of linear interpolation. Here, an example in which the look-up table LUTA is applied to the light source element LD22 and (u2, v2) = (5, 7) will be described.

[0100] (u2, v2) = (5, 7) means that u2>0, v2>0 and (u2 2 , v2 2 ) = (25, 49). In the look-up table LUTA, the four points enclosing this point are (ua 2 , va 2 ) = (0, 32), (ub 2 , va 2 ) = (32, 32), (ua 2 , vb 2 ) = (0, 64), (ub 2 , vb 2 ) = (32, 64) where u>0, v>0. The attenuation rates at those points are Luava = 0.8, Lubva = 0.717, Luavb = 0.6, and Lubvb = 0.51. By substituting these into the above equations (2) and (3), the operation of linear interpolation becomes the following equation (4).

[0101]

number

[0102] The circuit device of this embodiment described above includes a storage unit that stores a plurality of lookup tables and a brightness information calculation circuit that calculates brightness information. Each of the plurality of lookup tables shows the attenuation rate distribution of the light source elements of the backlight of a display device having a display panel and a backlight. The brightness information shows the brightness of the light that reaches the target pixel of the display panel from the backlight. The storage unit stores the first lookup table and the second lookup table as a plurality of lookup tables. The first lookup table is associated with a first light source element provided at a first position of the backlight and shows the first attenuation rate distribution of the first light source element. The second lookup table is associated with a second light source element provided at a second position different from the first position of the backlight and shows the second attenuation rate distribution of the second light source element. Based on the first lookup table, the brightness information calculation circuit determines the first attenuation rate of the light that reaches the target pixel from the first light source element and determines the second attenuation rate of the light that reaches the target pixel from the second light source element based on the second lookup table. The luminance information calculation circuit calculates luminance information based on the first and second attenuation rates.

[0103] According to this embodiment, a first lookup table is associated with a first light source element located at a first position, and a second lookup table is associated with a second light source element located at a second position different from the first position. This allows for the application of lookup tables with different attenuation rate distributions depending on the position of the light source element, making it possible to accurately determine the brightness of the light reaching each pixel from the backlight, taking into account the differences in light diffusion patterns depending on the position of the light source element. Since the brightness of the light reaching each pixel from the backlight can be accurately determined, the image data can be appropriately color-corrected.

[0104] In this embodiment, each lookup table may be a table in which the attenuation rate with respect to the distance from the light source element to the pixel of the display panel is associated. The luminance information calculation circuit may determine the first attenuation rate with respect to the distance from the first light source element to the target pixel based on the first lookup table. The luminance information calculation circuit may determine the second attenuation rate with respect to the distance from the second light source element to the target pixel based on the second lookup table.

[0105] According to this embodiment, the first attenuation rate at the distance from the first light source element to the target pixel is determined based on the first lookup table, and the second attenuation rate at the distance from the second light source element to the target pixel is determined based on the second lookup table. This makes it possible to determine the attenuation rate at the distance from the light source element to the target pixel based on lookup tables with different attenuation rate distributions depending on the position of the light source element.

[0106] In this embodiment, the second position may be closer to the first side of the display panel compared to the first position.

[0107] The attenuation rate distribution of light source elements positioned near the edges of the display panel is affected by reflected light from surrounding structures, and therefore differs from the attenuation rate distribution of light source elements positioned far from the edges of the display panel. According to this embodiment, the brightness of the light reaching each pixel from the backlight can be accurately determined by taking into account these differences in attenuation rate distribution.

[0108] In this embodiment, the backlight may also include a third light source element located at a third position closer to the third side opposite the first side of the display panel compared to the first position. The luminance information calculation circuit may calculate the third attenuation rate of the light reaching the target pixel from the third light source element based on a lookup table obtained by rotating the second lookup table by 180 degrees. The luminance information calculation circuit may calculate luminance information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

[0109] According to this embodiment, a lookup table for light source elements positioned near one side can be stored in the memory unit, and by rotating this lookup table, lookup tables for elements positioned near the other three sides can be generated. This saves the memory capacity of the memory unit.

[0110] In this embodiment, the second position may be closer to the first corner where the first and second sides of the display panel intersect, compared to the first position.

[0111] The attenuation rate distribution of light source elements positioned near the corners of the display panel is affected by reflected light from surrounding structures, and therefore differs from the attenuation rate distribution of light source elements positioned far from the corners of the display panel. According to this embodiment, the brightness of the light reaching each pixel from the backlight can be accurately determined by taking into account these differences in attenuation rate distribution.

[0112] In this embodiment, the backlight may also include a third light source element. The third light source element may be located in a third position closer to the second corner where the third side opposite the first side of the display panel intersects with the fourth side opposite the second side, compared to the first position. The luminance information calculation circuit may calculate the third attenuation rate of the light reaching the target pixel from the third light source element based on a lookup table obtained by rotating the second lookup table by 180 degrees. The luminance information calculation circuit may calculate luminance information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

[0113] According to this embodiment, a lookup table for a light source element located near one corner can be stored in the memory unit, and by rotating this lookup table, lookup tables for elements located near the other three corners can be generated. This saves the memory capacity of the memory unit.

[0114] In this embodiment, the first attenuation rate distribution may be a rotationally symmetric attenuation rate distribution with respect to the center. The second attenuation rate distribution may be a rotationally symmetric attenuation rate distribution with respect to the center.

[0115] The attenuation rate distribution of light sources positioned far from the edges or corners of the display panel is less affected by reflected light from the backlight or structures surrounding the display panel. Therefore, the attenuation rate distribution of these light sources is rotationally symmetric, or can be approximated by a rotationally symmetric attenuation rate distribution. On the other hand, the attenuation rate distribution of light sources positioned close to the edges or corners of the display panel is affected by reflected light from structures surrounding them. Therefore, the attenuation rate distribution of these light sources is not rotationally symmetric, or can be approximated by a rotationally symmetric attenuation rate distribution.

[0116] Furthermore, in this embodiment, the second attenuation rate distribution may have different attenuation characteristics in the direction from the center toward one side of the display panel and in the direction from the center toward a side other than one side of the display panel.

[0117] Reflected light from structures surrounding the backlight or display panel affects the region of the attenuation rate distribution that is close to the edges. Therefore, the attenuation characteristics in the direction toward the edges that are not affected by reflected light from the structures differ from the attenuation characteristics in the direction toward the edges that are affected by reflected light from the structures.

[0118] In this embodiment, the memory unit may store the third lookup table as a plurality of lookup tables. The third lookup table may be associated with a third light source element located at a third position different from the first and second positions of the backlight, and may show the third attenuation rate distribution of the third light source element. The second position may be closer to the first edge of the display panel than the first position. The third position may be closer to the first corner where the second and third edges of the display panel intersect, compared to the first position. The luminance information calculation circuit may determine the third attenuation rate of the light reaching the target pixel from the third light source element based on the third lookup table, and calculate luminance information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

[0119] According to this embodiment, the first to third lookup tables are associated with the first to third light source elements, which are located at different first to third positions. This allows the application of lookup tables with different attenuation rate distributions depending on the position of the light source elements, making it possible to accurately determine the brightness of the light reaching each pixel from the backlight, taking into account the differences in light diffusion patterns depending on the position of the light source elements.

[0120] Furthermore, the circuit device of this embodiment may include a luminance analysis circuit and a color correction circuit. The luminance analysis circuit may perform luminance analysis of image data and obtain dimming information for local dimming control based on the results of the luminance analysis. The luminance information calculation circuit may determine the first luminance of the light reaching the target pixel from the first light source element based on the dimming information and the first attenuation rate, and determine the second luminance of the light reaching the target pixel from the second light source element based on the dimming information and the second attenuation rate, and calculate luminance information based on the first and second luminances. The color correction circuit may perform color correction of the image data of the target pixel based on the luminance information and output the color-corrected image data to a display device.

[0121] According to this embodiment, the first luminance of the light reaching the target pixel from the first light source element and the second luminance of the light reaching the target pixel from the second light source element are accurately determined by considering the difference in light diffusion patterns depending on the position of the light source element. As a result, luminance information indicating the luminance of the light reaching the target pixel from the backlight is accurately determined, so that the color correction circuit can appropriately color correct the image data of the target pixel based on the luminance information.

[0122] Furthermore, the display system of this embodiment includes one of the above-described circuit devices and a display device.

[0123] Although this embodiment has been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novelty and effects of this disclosure. Therefore, all such modifications are included within the scope of this disclosure. For example, any term that appears at least once in the specification or drawings together with a broader or synonymous term may be replaced with that different term anywhere in the specification or drawings. Furthermore, all combinations of this embodiment and its modifications are also included within the scope of this disclosure. In addition, the configuration and operation of circuit devices, backlights, display devices, display systems, processing devices, and electronic devices are not limited to those described in this embodiment, and various modifications are possible. [Explanation of symbols]

[0124] 10…Light source element, 15…Light source element group, 20…Target pixel, 100…Circuit device, 110…Interface circuit, 130…Light source control circuit, 140…Brightness analysis circuit, 141…Image analysis unit, 142…Light source brightness determination unit, 150…Brightness information calculation circuit, 151…Coordinate analysis unit, 152…Brightness calculation unit, 160…Color correction circuit, 170…Storage unit, 200…Display device, 210…Backlight, 220…Display panel, 230…Display driver 240...Light source driver, 250...Display controller, 270...Structure, 300...Processing device, 400...Display system, 500...Electronic equipment, CNA, CNB, CNC, CND...Corner section, DDIM...Dimming data, DFPA, DFPB, DFPC...Attenuation rate distribution, EDA, EDB, EDC, EDD...Edge, IMA, IMB...Image data, LLD...Dimming data, LUTA, LUTB, LUTC...Lookup table

Claims

1. A circuit device for controlling a display device having a display panel and a backlight, A storage unit that stores a first lookup table and a second lookup table, A brightness information calculation circuit that calculates brightness information indicating the brightness of light reaching a target pixel of the display panel from the backlight, Includes, The first lookup table is associated with a first light source element provided at a first position of the backlight and shows a first attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the first light source element. The second lookup table is associated with a second light source element located at a second position different from the first position of the backlight, and shows a second attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the second light source element. The second position is, This position is closer to the first side of the display panel compared to the first position, The aforementioned backlight is The system includes a third light source element provided at a third position closer to the third side of the display panel opposite the first side, compared to the first position, The luminance information calculation circuit is, Based on the first lookup table, the first attenuation rate of the light reaching the target pixel from the first light source element is determined. Based on the second lookup table, the second attenuation rate of the light reaching the target pixel from the second light source element is determined. Based on the lookup table obtained by transforming the second lookup table so as to rotate the second attenuation rate distribution by 180 degrees, the third attenuation rate of the light reaching the target pixel from the third light source element is determined. A circuit device characterized by calculating the brightness information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

2. A circuit device for controlling a display device having a display panel and a backlight, A storage unit that stores a first lookup table and a second lookup table, A brightness information calculation circuit that calculates brightness information indicating the brightness of light reaching a target pixel of the display panel from the backlight, Includes, The first lookup table is associated with a first light source element provided at a first position of the backlight and shows a first attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the first light source element. The second lookup table is associated with a second light source element located at a second position different from the first position of the backlight, and shows a second attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the second light source element. The second position is, Compared to the first position, this position is closer to the first corner where the first and second sides of the display panel intersect. The aforementioned backlight is The third light source element is provided at a third position closer to the second corner where the third side opposite the first side of the display panel and the fourth side opposite the second side intersect, compared to the first position. The luminance information calculation circuit is, Based on the first lookup table, the first attenuation rate of the light reaching the target pixel from the first light source element is determined. Based on the second lookup table, the second attenuation rate of the light reaching the target pixel from the second light source element is determined. Based on the lookup table obtained by transforming the second lookup table so as to rotate the second attenuation rate distribution by 180 degrees, the third attenuation rate of the light reaching the target pixel from the third light source element is determined. A circuit device characterized by calculating the brightness information based on the first attenuation rate, the second attenuation rate, and the third attenuation rate.

3. A circuit device for controlling a display device having a display panel and a backlight, A storage unit that stores a first lookup table and a second lookup table, A brightness information calculation circuit that calculates brightness information indicating the brightness of light reaching a target pixel of the display panel from the backlight, Includes, The first lookup table is associated with a first light source element provided at a first position of the backlight and shows a first attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the first light source element. The second lookup table is associated with a second light source element located at a second position different from the first position of the backlight, and shows a second attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the second light source element. The luminance information calculation circuit is, Based on the first lookup table, the first attenuation rate of light reaching the target pixel from the first light source element is determined, and based on the second lookup table, the second attenuation rate of light reaching the target pixel from the second light source element is determined, and the luminance information is calculated based on the first and second attenuation rates. The first attenuation rate distribution is, The attenuation rate distribution is rotationally symmetric with respect to the first position, The second attenuation rate distribution is, A circuit device characterized by having a non-rotationally symmetric attenuation rate distribution centered on the second position.

4. In the circuit device described in claim 3, The second attenuation rate distribution is, A circuit device characterized in that the attenuation characteristics in the direction from the second position toward one side of the display panel are different from the attenuation characteristics in the direction from the second position toward a side of the display panel other than the one side.

5. In a circuit device according to any one of claims 1 to 4, The first lookup table is, This is a table in which the attenuation rate of light is associated with the distance from the first light source element to the pixels of the display panel. The aforementioned second lookup table is, This is a table in which the attenuation rate of light is associated with the distance from the second light source element to the pixels of the display panel. The luminance information calculation circuit is, The first attenuation rate at the distance from the first light source element to the target pixel is determined based on the first lookup table. A circuit device characterized in that the second attenuation rate at the distance from the second light source element to the target pixel is determined based on the second lookup table.

6. In a circuit device according to any one of claims 1 to 4, The aforementioned storage unit is A third lookup table is stored that corresponds to a fourth light source element provided at a fourth position different from the first and second positions of the backlight, and shows a third attenuation rate distribution, which is the attenuation rate distribution of light reaching the pixels of the display panel from the fourth light source element. The second position is, This position is closer to the first side of the display panel compared to the first position, The fourth position is, Compared to the first position, this position is closer to the third corner where the second and third sides of the display panel intersect. The luminance information calculation circuit is, A circuit device characterized by determining the fourth attenuation rate of light reaching the target pixel from the fourth light source element based on the third lookup table, and further calculating the brightness information based on the fourth attenuation rate.

7. In a circuit device according to any one of claims 1 to 4, Brightness analysis circuit, Color correction circuit, Includes, The luminance analysis circuit described above is Brightness analysis of image data is performed, and based on the results of the brightness analysis, dimming information for the local dimming control of the backlight is obtained. The luminance information calculation circuit is, Based on the dimming information and the first attenuation rate, a first brightness of light reaching the target pixel from the first light source element is determined; based on the dimming information and the second attenuation rate, a second brightness of light reaching the target pixel from the second light source element is determined; and the brightness information is calculated based on the first brightness and the second brightness. The aforementioned color correction circuit is A circuit device characterized by performing color correction on the image data of the target pixel based on the brightness information, and outputting the color-corrected image data to the display device.

8. A circuit device according to any one of claims 1 to 4, The aforementioned display device, A display system characterized by including the following.

Images