Circuit device and head-up display device

Abstract

To provide a circuit device, etc., with which it is possible to improve the visibility of a background in a region of HUD display where no display object exists.SOLUTION: A circuit device 100 is used in a head-up display device 50 that includes a display panel 20 and a backlight device 10 having a plurality of light-emitting elements LS. The circuit device 100 includes a distortion correction circuit 110 and an image analysis circuit 120. The distortion correction circuit 110 corrects a distortion with respect to input image data IMA and outputs output image data IMB after distortion correction. The image analysis circuit 120 analyzes the image data to be analyzed, which is the input image data IMA or the output image data IMB, and performs backlight control processing, on the basis of the analysis result, for turning off a light-emitting element that corresponds to a display region of the display panel 20, the color of which changes to a transparent color when projected by the head-up display device 50, among the plurality of display regions corresponding to the plurality of light-emitting elements.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a circuit device, a head-up display device, and the like. [Background technology]

[0002] Head-up display devices are known that project an image onto a transparent screen, allowing a user looking at the screen to visually recognize a virtual image. Patent Document 1 discloses a vehicle display device that includes a liquid crystal display, a backlight source provided on the back of the liquid crystal display, and a reflector that reflects light that has passed through the liquid crystal display toward the windshield. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-117071 Summary of the Invention [Problem to be solved by the invention]

[0004] To a user looking at a head-up display device, a virtual image projected by the head-up display device appears superimposed on the real world seen through the screen. Areas of the display area of ​​the head-up display device where no display objects are present appear transparent to the user, meaning the real world is seen as is. However, due to the nature of head-up display devices, which project light onto a screen, some light is projected onto transparent areas where no display objects are present, which creates the problem of areas that should be transparent appearing whitish. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to a circuit device used in a head-up display device including a display panel and a backlight device having a plurality of light-emitting elements, the circuit device including: a distortion correction circuit that performs distortion correction on input image data and outputs output image data after the distortion correction; and an image analysis circuit that analyzes image data to be analyzed, which is the input image data or the output image data, and, based on the analysis results, performs backlight control processing to turn off light-emitting elements corresponding to display areas that become transparent when projected by the head-up display device, among a plurality of display areas corresponding to the plurality of light-emitting elements on the display panel.

[0006] Another aspect of the present disclosure relates to a head-up display device including the circuit device described above, the display panel, and the backlight device. [Brief explanation of the drawings]

[0007] [Figure 1] An example of a HUD display in a conventional head-up display device. [Figure 2] 1 shows a first configuration example of a circuit device and a head-up display device. [Figure 3] 3A and 3B are a plan view and a side view of a backlight device and a display panel. [Figure 4] An example of a display area corresponding to a light-emitting element. [Figure 5] 10 shows a display example according to the present embodiment. [Figure 6] 1 shows a first detailed configuration example of a circuit device. [Figure 7] FIG. 4 is a diagram illustrating the operation of the circuit device in the first detailed configuration example. [Figure 8] 10 is a timing chart in the case where backlight control is performed in a subsequent stage of the circuit device without using the present embodiment. [Figure 9] 10 is a timing chart showing a case where backlight control is performed in a subsequent stage of the circuit device when the present embodiment is used. [Figure 10] 10 shows a second configuration example of a circuit device and a head-up display device. [Figure 11] 10 shows a second detailed configuration example of a circuit device. [Figure 12] 10A to 10C are diagrams illustrating the operation of a circuit device in a second detailed configuration example. [Figure 13] 10 shows a third example of a circuit device configuration. [Figure 14] 10 is a flowchart showing the processing procedure of a HUD system including a circuit device of a third configuration example. [Figure 15] 10A and 10B are diagrams for explaining light control of each light-emitting element. DETAILED DESCRIPTION OF THE INVENTION

[0008] Preferred embodiments of the present disclosure will be described in detail below. Note that the embodiments described below do not unduly limit the scope of the claims, and not all of the configurations described in the embodiments are necessarily essential components.

[0009] 1. About HUD display Figure 1 shows an example of a HUD display in a conventional head-up display device. Note that the image distortion that occurs during projection is ignored here, but the problems with HUD display described below apply even when image distortion is present. HUD stands for head-up display, and in the following, head-up display devices may be abbreviated as HUD where appropriate.

[0010] The top part of Figure 1 shows an example of an image displayed on the liquid crystal panel of a HUD. Image 1 includes several display objects 2. On the liquid crystal panel, pixels in the area where display objects 2 are displayed transmit light according to the grayscale value, while pixels in areas other than display objects 2 do not transmit light.

[0011] The bottom part of Figure 1 shows an example of the display when a head-up display device projects the image in the top part into the user's field of vision. The backlight device emits light, which passes through the LCD panel and is reflected by a reflector toward the screen. The light reflected by the screen then enters the user's eyes, projecting a virtual image object 6 corresponding to object 2 into the user's field of vision. This virtual image object 6 is superimposed on the real world, which is the background of the HUD display.

[0012] In this case, the areas of the HUD display area 5 where the virtual image object 6 is not displayed are opaque to the liquid crystal panel, and therefore should be transparent areas with no display, and the background should be visible. However, because a small amount of light from the backlight device passes through the opaque areas of the liquid crystal panel, the transparent areas of the HUD display appear slightly brighter than their surroundings. For example, in dark environments such as at night or inside a tunnel, the areas of the display area 5 where the virtual image object 6 is not displayed appear whitish, which may reduce the visibility of the background that overlaps those areas.

[0013] 2. First configuration example 2 shows a first configuration example of the circuit device 100 and the head-up display device 50 according to this embodiment. The head-up display device 50 includes a display device 30 and the circuit device 100. Note that the head-up display device 50 includes an optical system such as a reflector, but this is not shown in FIG.

[0014] The display device 30 includes a backlight device 10 and a display panel 20. A plan view and a side view of the backlight device 10 and the display panel 20 are shown in FIG.

[0015] The display panel 20 is a liquid crystal display panel in which pixels are arranged in an array. In the following, a case where the display panel 20 is a transmissive liquid crystal panel will be described as an example, but the display panel 20 may also be a reflective liquid crystal panel. In Figure 3, the direction parallel to the horizontal scanning direction of the display panel 20 is defined as the x direction, and the direction parallel to the vertical scanning direction is defined as the y direction. Furthermore, the direction perpendicular to the x direction and y direction and extending from the backlight device 10 to the display panel 20 is defined as the z direction.

[0016] The backlight device 10 includes a plurality of light-emitting elements LS arranged on a surface parallel to the xy plane. The light-emitting elements LS are arranged in approximately the same area as the pixel array of the display panel 20 in a planar view. The light-emitting elements LS are arranged in an array so that when all of the light-emitting elements LS are lit, light is irradiated onto the entire surface of the pixel array of the display panel 20. FIG. 3 shows an example in which the light-emitting elements LS are arranged in 9 rows and 16 columns. The light-emitting elements LS in each row are arranged parallel to the x direction, and the light-emitting elements LS in each column are arranged parallel to the y direction. However, FIG. 3 is just an example of the arrangement of the light-emitting elements, and the arrangement of the light-emitting elements is not limited to this.

[0017] Each light-emitting element LS of the backlight device 10 is a light-emitting element such as an LED that can be independently controlled to be turned on or off. LED stands for Light Emitting Diode. Note that, hereinafter, turning on a light-emitting element is also referred to as "illuminating," and turning off a light-emitting element is also referred to as "extinct." Each light-emitting element LS may be configured to be independently dimmable, and the dimming function may be used to independently control the on or off of each light-emitting element LS.

[0018] 2 includes a distortion correction circuit 110, an image analysis circuit 120, and an output circuit 130. The circuit device 100 is, for example, an integrated circuit device in which a plurality of circuit elements are integrated on a semiconductor substrate.

[0019] The distortion correction circuit 110 performs distortion correction on the input image data IMA using coordinate conversion between pixel coordinates in the input image data IMA and pixel coordinates in the output image data IMB, and outputs output image data IMB, which is the corrected image data. Distortion correction is image correction that applies image distortion to the image that is opposite to the image distortion that occurs when the image displayed on the display panel 20 is projected, thereby creating a HUD display with no or reduced distortion. Image distortion due to projection includes image distortion due to the curved surface of the screen, image distortion due to the HUD optical system, or both.

[0020] The distortion correction circuit 110 includes a coordinate counter 112 that counts pixel coordinates GZB in the output image data IMB. "Counting pixel coordinates" means sequentially outputting coordinates indicating the position of each pixel, such as (0,0), (1,0), . . ., (1919,0), (0,1), (1,1), . . ., (1919,1), . . ., (0,1079), (1,1079), . . ., (1919,1079), when the image size is 1920 x 1080 pixels, for example.

[0021] The distortion correction circuit 110 corresponds to a reverse warp engine, and the coordinate counter 112 is a coordinate counter used for the reverse warp. Reverse warp is a warp process that converts pixel coordinates on the output image data IMB into corresponding reference coordinates and obtains pixel data on the output image data IMB from pixel data on the input image data IMA at the reference coordinates. The coordinate conversion is defined by warp parameters. The warp parameters are a table that associates pixel coordinates with reference coordinates, a table that indicates the amount of movement between pixel coordinates and reference coordinates, or the coefficients of a polynomial that associates pixel coordinates with reference coordinates.

[0022] The output circuit 130 transmits the output image data IMB to the display device 30. The output circuit 130 may be a transmission circuit of various communication interfaces, examples of which include LVDS, DVI, DisplayPort, GMSL, and GVIF. LVDS stands for Low Voltage Differential Signaling, DVI stands for Digital Visual Interface, GMSL stands for Gigabit Multimedia Serial Link, and GVIF stands for Gigabit Video Interface.

[0023] Although not shown, a display controller and a display driver are provided between the output circuit 130 and the display panel 20. The display controller and the display driver are configured by one or more integrated circuit devices separate from the integrated circuit device that constitutes the distortion correction circuit 110. Alternatively, the integrated circuit device that constitutes the distortion correction circuit 110 may incorporate the functions of the display controller, or may incorporate the functions of the display controller and the display driver.

[0024] The image analysis circuit 120 performs image analysis in parallel with distortion correction, and outputs a control signal CTL that independently controls on or off each light-emitting element LS of the backlight device 10. Specifically, the image analysis circuit 120 outputs the control signal CTL based on the pixel coordinate GZB output by the coordinate counter 112 and the pixel data of the pixel coordinate GZB in the output image data IMB output by the distortion correction circuit 110. This will be described below with reference to FIGS. 4 and 5.

[0025] Fig. 4 shows an example of a display area corresponding to the light-emitting element LS. Fig. 4 shows a display area ARa on the display panel 20 corresponding to the light-emitting element LSa, and a display area ARb on the display panel 20 corresponding to the light-emitting element LSb. Although only display areas corresponding to two light-emitting elements are shown here, there are display areas corresponding to each light-emitting element.

[0026] A display area corresponding to a light-emitting element is an area on the display panel 20 that is illuminated by light emitted from that light-emitting element. That is, an image displayed in that display area is projected by light emitted from the light-emitting element corresponding to that display area. A portion of a display area corresponding to a light-emitting element may overlap with a portion of a display area corresponding to an adjacent light-emitting element. For example, when the display area corresponding to each light-emitting element is a rectangular area, it can be specified by information specifying the starting coordinates, width, and height. Information indicating the display area corresponding to each light-emitting element is written, for example, from a processing device external to the circuit device 100 to a register or the like (not shown) within the circuit device 100, or is stored in advance in a non-volatile memory (not shown) provided within the circuit device 100.

[0027] The image analysis circuit 120 determines the display area to which the pixel coordinate GZB output by the coordinate counter 112 belongs, and determines whether to turn off the light-emitting element corresponding to that display area based on whether the pixel data for that pixel coordinate GZB is a transparent color in the HUD display. A transparent color is a color that, when the color displayed on the display panel 20 is projected by the HUD, nothing is displayed in the HUD display and the background is visible as is. Specifically, since the HUD display should become transparent when the pixels of the display panel 20 block light, a color that appears black when displayed on the display panel 20 corresponds to a transparent color. In the following, it is assumed that black in the image data becomes a transparent color in the HUD display.

[0028] If all pixel data in a display area is black, the image analysis circuit 120 turns off the light-emitting element corresponding to that display area, and if there is even one pixel data that is not black in the display area, the image analysis circuit 120 turns on the light-emitting element corresponding to that display area. In the example of FIG. 4, the light-emitting element LSa corresponding to the display area ARa that overlaps the display object 2 is determined to be on, and the light-emitting element LSb corresponding to the display area ARb that does not overlap the display object 2 is determined to be off. Note that the image analysis circuit 120 may turn off the light-emitting element corresponding to that display area if the number of pixel data that is not transparent in the display area is equal to or less than a predetermined number. The predetermined number is, for example, 1 to several tens.

[0029] FIG. 5 shows an example of a HUD display in this embodiment. The top diagram shows the on / off state of each light-emitting element. White circles indicate light-emitting elements that are off, and black circles indicate light-emitting elements that are on. The middle diagram shows the display area AR projected by the light-emitting elements that are on in the top diagram. The display area AR includes only the display object 2 and its surroundings, and most of the area where the display object 2 is not present is included in the display area AR. The bottom diagram shows the HUD display when the image in the middle diagram is projected by the light-emitting elements that are turned on in the top diagram. The light-emitting elements corresponding to the area where the display object 6 is present are turned on, and the light-emitting elements corresponding to the area where the display object 6 is not present are turned off, so the display object 6 is displayed and most of the area where the display object 6 is not present becomes whitish. R It becomes transparent without any effect, allowing the background to be seen.

[0030] The distortion correction circuit 110 and the image analysis circuit 120 are logic circuits. The distortion correction circuit 110 and the image analysis circuit 120 may each be configured as an individual circuit, or the distortion correction circuit 110 and the image analysis circuit 120 may be configured as an integrated circuit using automatic placement and routing or the like. Also, some or all of these logic circuits may be realized by a processor such as a DSP (Digital Signal Processor). In this case, a program or instruction set describing the function of each circuit is stored in memory, and the function of each circuit is realized by the processor executing the program or instruction set.

[0031] Fig. 6 shows a first detailed configuration example of the circuit device 100. The distortion correction circuit 110 includes a coordinate counter 112, a correction coordinate conversion circuit 113, an interpolation circuit 114, and a memory circuit 115. Fig. 7 is a diagram illustrating the operation of the circuit device 100 in the first detailed configuration example.

[0032] The coordinate counter 112 outputs pixel coordinates GZB=(x,y) on the output image data IMB. The correction coordinate transformation circuit 113 converts the pixel coordinates (x,y) into reference coordinates GZA=(u,v), which are coordinates on the input image data IMA. The memory circuit 115 temporarily stores the input image data IMA and outputs pixel data PXD of the reference coordinates (u,v). Specifically, the correction coordinate transformation circuit 113 converts the reference coordinates (u,v) into a read address, and the memory circuit 115 reads the pixel data PXD of the reference coordinates (u,v) from the read address. More specifically, the correction coordinate transformation circuit 113 outputs read addresses of multiple pixels around the reference coordinates (u,v), and the memory circuit 115 reads the pixel data of the multiple pixels. The interpolation circuit 114 interpolates the multiple pixel data read corresponding to the reference coordinates (u,v) to obtain pixel data of the pixel coordinates (x,y) in the output image data IMB.

[0033] The image analysis circuit 120 determines which display area corresponds to the light-emitting element the pixel coordinates (x, y) output by the coordinate counter 112 belong to. The image analysis circuit 120 uses the determination result and the pixel data of the pixel coordinates (x, y) output by the interpolation circuit 114 to determine whether or not to turn off each light-emitting element.

[0034] In the above-described embodiment, the circuit device 100 is used in a head-up display device 50. The head-up display device 50 includes a display panel 20 and a backlight device 10 having a plurality of light-emitting elements LS. The circuit device 100 also includes a distortion correction circuit 110 and an image analysis circuit 120. The distortion correction circuit 110 performs distortion correction on input image data IMA and outputs distortion-corrected output image data IMB. The image analysis circuit 120 analyzes the analysis target image data, which is the input image data IMA or the output image data IMB, and, based on the analysis results, performs backlight control processing to turn off light-emitting elements LS corresponding to display regions AR that will be transparent when projected by the head-up display device 50, among a plurality of display regions AR corresponding to the plurality of light-emitting elements LS on the display panel 20.

[0035] In the first configuration example, the image analysis circuit 120 analyzes the output image data IMB as the image data to be analyzed, but the image analysis circuit 120 may analyze the input image data IMA as the image data to be analyzed. An example of this will be described later in the second configuration example.

[0036] According to this embodiment, a display area that will be transparent when projected by the HUD is determined by image analysis. Then, among the multiple light-emitting elements LS arranged in the backlight device 10, the light-emitting elements LS that correspond to the display area that will be transparent when projected by the HUD are turned off, so that the display area does not appear whitish in the HUD display but remains a true transparent area. Therefore, even when the background is dark, such as at night or inside a tunnel, the area without any displayed object in the HUD display remains a true transparent area, and the visibility of the background is not reduced.

[0037] In addition, in this embodiment, the image analysis circuit 120 analyzes whether the image data to be analyzed in each display area AR of the multiple display areas is transparent color data, and performs backlight control processing to turn off the light-emitting element LS corresponding to the display area AR where the image data to be analyzed is analyzed to be transparent color data.

[0038] According to this embodiment, the image analysis circuit 120 performs image analysis to analyze whether the image data to be analyzed in each display area AR is transparent color data, thereby determining which of the multiple display areas AR will become transparent color when projected by the head-up display device 50.

[0039] In this embodiment, the distortion correction circuit 110 also includes a coordinate counter 112 that counts pixel coordinates GZB of the image data to be analyzed. The image analysis circuit 120 determines which of the multiple display areas AR each pixel of the image data to be analyzed belongs to, based on the pixel coordinates GZB output by the coordinate counter 112, and determines which display areas AR will be transparent based on the determination result.

[0040] According to this embodiment, the pixel coordinates GZB output by the coordinate counter 112 indicate the pixel coordinates of each pixel in the image data to be analyzed, so the image analysis circuit 120 can determine the display area AR to which each pixel of the image data to be analyzed belongs among multiple display areas AR based on the pixel coordinates GZB.

[0041] Furthermore, in this embodiment, the image analysis circuit 120 determines whether the pixel data belonging to each display area AR of the multiple display areas is transparent color data based on the pixel coordinate GZB output by the coordinate counter 112 and the pixel data of the image data to be analyzed at the pixel coordinate GZB, thereby determining whether each display area AR is a display area AR that will be transparent color.

[0042] According to this embodiment, the image analysis circuit 120 can determine the display area AR to which the pixel coordinate GZB belongs and whether the pixel data at that pixel coordinate GZB is transparent data. This allows the image analysis circuit 120 to determine whether each display area AR is a display area that will be transparent when displayed on the HUD.

[0043] Furthermore, according to this embodiment, the image data to be analyzed is the input image data IMA input to the distortion correction circuit 110 or the output image data IMB output by the distortion correction circuit 110, and the pixel coordinates output by the coordinate counter 112 included in the distortion correction circuit 110 are used for image analysis. As a result, the distortion correction circuit 110 performs distortion correction, and in parallel with this, the image analysis circuit 120 can control the backlight through image analysis, thereby eliminating or simplifying the need for adjusting the time lag between HUD display and backlight control. This will be explained below using Figures 8 and 9.

[0044] FIG. 8 shows a timing chart when backlight control is performed downstream of the circuit device 100 without using this embodiment. Note that FIG. 8 is a schematic illustration of the timing of backlight control and does not necessarily show the exact timing. As shown in FIG. 8, in the path for displaying an image on the display panel 20, the distortion correction circuit 110 sequentially outputs output image data IMB for each line, and the output image data IMB for each line is sequentially displayed on the display panel 20. Meanwhile, in the path for backlight control, for example, a frame memory is provided downstream of the circuit device 100 to buffer one frame of output image data IMB, and the output image data IMB is analyzed to perform backlight control. As a result, the timing of image display and the timing of backlight control are shifted by, for example, one frame or more.

[0045] FIG. 9 shows a timing chart of backlight control performed downstream of the circuit device 100 when this embodiment is used. Note that FIG. 9 is a schematic illustration of the timing of backlight control and does not necessarily show the exact timing. As shown in FIG. 9 , in the path for displaying an image on the display panel 20, the distortion correction circuit 110 sequentially outputs output image data IMB for each line, and the output image data IMB for each line is sequentially displayed on the display panel 20. This is similar to FIG. 8 . In the path for backlight control, image analysis is performed in parallel with distortion correction, thereby enabling the image display timing and the backlight control timing to be closer together than in the case of FIG. 8 . This eliminates or simplifies timing adjustment compared to the case of FIG. 8 . Note that in a second configuration example described later, image analysis is performed in parallel with distortion correction, and, like the first configuration example, timing adjustment is eliminated and simplified compared to the case of FIG. 8 .

[0046] In this embodiment, the image data to be analyzed is the output image data IMB. The distortion correction circuit 110 converts the pixel coordinates GZB=(x,y) output by the coordinate counter 112 into reference coordinates GZA=(u,v) on the input image data IMA, and performs distortion correction by outputting pixel data of the output image data IMB at pixel coordinates (x,y) based on the pixel data of the input image data IMA at the reference coordinates (u,v). The image analysis circuit 120 determines to which of the multiple display areas AR the pixel coordinates (x,y) output by the coordinate counter 112 belong, and determines whether the display area AR to which the pixel coordinates (x,y) belong is a display area AR that will be transparent, based on the pixel data of the output image data IMB at pixel coordinates (x,y) output by the distortion correction circuit 110.

[0047] According to this embodiment, backlight control is performed by image analysis based on the pixel coordinates (x, y) output by the coordinate counter 112 used for distortion correction and the pixel data of the output image data IMB output by the distortion correction circuit 110 corresponding to those pixel coordinates (x, y). This allows distortion correction and backlight control by image analysis to be processed in parallel, thereby eliminating or simplifying the time lag adjustment between HUD display and backlight control as described above.

[0048] 3. Second configuration example 10 shows a second configuration example of the circuit device 100 and the head-up display device 50. Components that have already been described are given the same reference numerals, and descriptions of those components will be omitted where appropriate.

[0049] In the second configuration example, the coordinate counter 112 counts pixel coordinates GZA2 in the input image data IMA. The image analysis circuit 120 performs image analysis in parallel with distortion correction, and outputs a control signal CTL that independently controls each light-emitting element LS of the backlight device 10 to turn on or off. Specifically, the image analysis circuit 120 outputs the control signal CTL based on the pixel coordinates GZA2 output by the coordinate counter 112 and the pixel data of the pixel coordinates GZA2 in the input image data IMA.

[0050] The distortion correction circuit 110 corresponds to a reverse warp engine. Pixel data of the input image data IMA is sequentially input to the reverse warp engine, and a coordinate counter 112 counts the pixel coordinates of the sequentially input pixel data. The image analysis circuit 120 converts the pixel coordinate GZA2 into a destination coordinate in the output image data IMB, and determines whether to turn off each light-emitting element based on the destination coordinate and the pixel data of the pixel coordinate GZA2 in the input image data IMA.

[0051] Fig. 11 shows a second detailed configuration example of the circuit device 100. The distortion correction circuit 110 includes a coordinate counter 112 and a distortion correction unit 119. The distortion correction unit 119 includes a correction coordinate conversion circuit 113, an interpolation circuit 114, a memory circuit 115, and a correction coordinate counter 116. The image analysis circuit 120 includes a coordinate conversion circuit 121 and a determination circuit 122. Fig. 12 is a diagram illustrating the operation of the circuit device 100 in the second detailed configuration example.

[0052] The memory circuit 115 temporarily stores the input image data IMA. The coordinate counter 112 counts the pixel coordinates GZA2=(u2, v2) of the pixel data written to the memory circuit 115.

[0053] The correction coordinate counter 116 outputs pixel coordinates GZB=(x,y) on the output image data IMB. The correction coordinate transformation circuit 113 transforms the pixel coordinates (x,y) into reference coordinates GZA=(u,v), which are coordinates on the input image data IMA. This transformation is called the first coordinate transformation. The memory circuit 115 outputs pixel data PXD of the reference coordinates (u,v). Specifically, the correction coordinate transformation circuit 113 outputs read addresses of multiple pixels around the reference coordinates (u,v), and the memory circuit 115 reads out pixel data of the multiple pixels. The interpolation circuit 114 interpolates the multiple pixel data read out corresponding to the reference coordinates (u,v) to obtain pixel data of the pixel coordinates (x,y) in the output image data IMB.

[0054] The coordinate conversion circuit 121 of the image analysis circuit 120 converts the pixel coordinates (u2, v2) output by the coordinate counter 112 into destination coordinates GZB2=(x2, y2), which are coordinates on the output image data IMB. This conversion is called the second coordinate conversion. The second coordinate conversion is the inverse conversion of the first coordinate conversion. The judgment circuit 122 determines which display area corresponds to the light-emitting element the destination coordinates (x2, y2) output by the coordinate conversion circuit 121 belong to. The judgment circuit 122 uses the judgment result and the pixel data of the pixel coordinates (u2, v2) in the input image data IMA to determine whether or not to turn off each light-emitting element.

[0055] The destination coordinates (x2, y2) indicate where in the output image data IMB the pixel data at pixel coordinates (u2, v2) in the input image data IMA will move to. The determination circuit 122 performs area determination using the destination coordinates (x2, y2), thereby determining to which display area the pixel data at pixel coordinates (u2, v2) in the input image data IMA will move.

[0056] In the above embodiment, the image data to be analyzed is input image data IMA. The image analysis circuit 120 includes a coordinate conversion circuit 121 and a determination circuit 122. The coordinate conversion circuit 121 converts pixel coordinates GZA2=(u2,v2) output by the coordinate counter 112 into destination coordinates GZB2=(x2,y2) on the output image data IMB. The determination circuit 122 determines to which of multiple display areas AR the destination coordinates (x2,y2) belong, and determines whether the display area AR to which the destination coordinates (x2,y2) belong is a display area AR that will be transparent, based on the pixel data of the input image data IMA at pixel coordinates (u2,v2).

[0057] According to this embodiment, the pixel coordinates GZA2=(u2, v2) of the input image data IMA input to the distortion correction circuit 110 are counted, and the pixel coordinates (u2, v2) are converted to destination coordinates (x2, y2) on the output image data IMB. Backlight control is then performed by image analysis based on the destination coordinates (x2, y2) and the pixel data of the pixel coordinates (u2, v2) in the input image data IMA. This allows distortion correction and backlight control by image analysis to be processed in parallel, eliminating or simplifying the time lag adjustment between HUD display and backlight control, as described above with reference to FIGS. 8 and 9.

[0058] In this embodiment, the distortion correction circuit 110 includes a correction coordinate counter 116 that counts coordinates on the output image data IMB, and performs distortion correction based on a first coordinate transformation that converts the coordinates output by the correction coordinate counter 116 into reference coordinates GZA on the input image data IMA. The coordinate transformation circuit 121 performs a second coordinate transformation, which is the inverse transformation of the first coordinate transformation, on the pixel coordinates GZA2=(u2,v2) output by the coordinate counter 112, to find the destination coordinates GZB2=(x2,y2).

[0059] According to this embodiment, in addition to the correction coordinate counter 116 used for reverse warp, there are provided a coordinate counter 112 that counts pixel coordinates GZA2=(u2,v2) of the input image data IMA, and a coordinate conversion circuit 121 that converts the pixel coordinates (u2,v2) into destination coordinates GZB2=(x2,y2) on the output image data IMB. This makes it possible to determine whether the display area AR will be a transparent color in the HUD display, using the input image data IMA as the image data to be analyzed.

[0060] 4.Third configuration example 13 shows a third configuration example of the circuit device 100. The circuit device 100 includes a distortion correction circuit 110, an image analysis circuit 120, an output circuit 130, an interface circuit 140, a brightness control value calculation circuit 150, and an interface circuit 160. Components that have already been described are given the same reference numerals, and descriptions of those components will be omitted as appropriate. While FIG. 13 shows an example in which the interface circuit 140, the brightness control value calculation circuit 150, and the interface circuit 160 are combined with the first configuration example, the interface circuit 140, the brightness control value calculation circuit 150, and the interface circuit 160 may also be combined with the second configuration example.

[0061] FIG. 14 is a flowchart showing the processing procedure of the HUD system including the circuit device 100 of the third configuration example.

[0062] In step S1, the illuminance sensor measures the illuminance of the external environment. The illuminance of the external environment is the illuminance of the real world that the user visually recognizes along with the HUD display. In step S2, the processing device 200 calculates the brightness adjustment amount KDI for the entire screen based on the measurement value of the illuminance sensor. The processing device 200 is a so-called SoC, such as a processor such as a CPU or microcomputer. SoC stands for System on Chip. CPU stands for Central Processing Unit.

[0063] In step S3, the processing device 200 transmits the luminance adjustment amount KDI to the interface circuit 140 of the circuit device 100. The interface circuit 140 is a serial interface conforming to, for example, the SPI standard or the I2C standard. SPI stands for Serial Peripheral Interface, and I2C stands for Inter-Integrated Circuit. The processing device 200 also transmits the luminance variation correction amount BHI of each light-emitting element to the interface circuit 140.

[0064] In step S4, the brightness control value calculation circuit 150 of the circuit device 100 performs dimming of each light-emitting element while taking into account the brightness adjustment amount KDI of the entire screen. Figure 15 shows a diagram for explaining dimming of each light-emitting element. Here, it is assumed that the backlight device 10 has 3 x 3 light-emitting elements.

[0065] A single brightness adjustment amount KDI for the entire screen is set for all light-emitting elements; in the example of FIG. 15, KDI = 0.5. A single brightness variation correction amount BHI is set for each light-emitting element. The distortion correction circuit 110 performs distortion correction on the input image data IMA received from the processing device 200, and the image analysis circuit 120 performs image analysis in parallel with the distortion correction to output a control signal CTL that controls each light-emitting element to be on or off. In FIG. 15, only off is shown, and blanks indicate on. The brightness control value calculation circuit 150 calculates the brightness control value for each light-emitting element by multiplying the brightness adjustment amount KDI for the entire screen by the brightness variation correction amount BHI. The brightness control value calculation circuit 150 sets the brightness control value of the light-emitting element that is instructed to be off by the control signal CTL to zero and outputs it as a control signal CTLB.

[0066] In step S5, the interface circuit 160 outputs a control signal CTLB to the backlight device 10, and the backlight device 10 dims each light-emitting element based on the control signal CTLB. Light-emitting elements whose brightness control value is zero are turned off, and light-emitting elements whose brightness control value is greater than zero emit light at a brightness controlled by that brightness control value. Since brightness variations are corrected by the brightness variation correction amount BHI, the lit light-emitting elements emit light at the same brightness.

[0067] In the above-described embodiment, the circuit device 100 includes a brightness control value calculation circuit 150 and an interface circuit 160. The brightness control value calculation circuit 150 calculates a brightness control value for each light-emitting element LS of the plurality of light-emitting elements by modifying the backlight control signal received from the external processing device 200 based on the result of the backlight control processing from the image analysis circuit 120. The interface circuit 160 outputs the brightness control value for each light-emitting element LS to the backlight device 10. In the third configuration example, the backlight control signal is a brightness adjustment amount KDI and a brightness variation correction amount BHI for the entire screen, the result of the backlight control processing is a control signal CTL, and the brightness control value for each light-emitting element LS is output to the backlight device 10 as a control signal CTLB.

[0068] According to this embodiment, it is possible to combine backlight control by the image analysis circuit 120 with dimming control by the external processing device 200. Specifically, the dimming control by the external processing device 200 is reflected on light-emitting elements that the image analysis circuit 120 determines to be turned on through image analysis. Furthermore, light-emitting elements that the image analysis circuit 120 determines to be turned off through image analysis are controlled to be turned off regardless of the dimming control by the external processing device 200. Normally, the backlight device 10 has one control input system, but according to this embodiment, the dimming control by the processing device 200 and the backlight control by the image analysis circuit 120 can be combined and input to the one control input system.

[0069] The circuit device of the present embodiment described above is used in a head-up display device. The head-up display device includes a display panel and a backlight device having a plurality of light-emitting elements. The circuit device includes a distortion correction circuit and an image analysis circuit. The distortion correction circuit performs distortion correction on input image data and outputs distortion-corrected output image data. The image analysis circuit analyzes analysis target image data, which is input image data or output image data, and, based on the analysis results, performs backlight control processing to turn off light-emitting elements corresponding to display areas that will be transparent when projected by the head-up display device, out of a plurality of display areas corresponding to a plurality of light-emitting elements on the display panel.

[0070] According to this embodiment, a display area that will be transparent when projected by a head-up display device is determined by image analysis. Then, among the multiple light-emitting elements arranged in the backlight device, light-emitting elements corresponding to the display area that will be transparent when projected by the head-up display device are turned off, so that the display area remains transparent without appearing whitish in the HUD display. As a result, even when the background is dark, such as at night or inside a tunnel, areas without displayed objects remain transparent in the HUD display, preventing a decrease in the visibility of the background.

[0071] In addition, in this embodiment, the image analysis circuit may analyze whether the image data to be analyzed in each of the multiple display areas is transparent color data, and perform backlight control processing to turn off the light-emitting element corresponding to the display area where the image data to be analyzed is analyzed to be transparent color data.

[0072] According to this embodiment, the image analysis circuit performs image analysis to determine whether the image data to be analyzed in each display area is transparent color data, thereby determining which of the multiple display areas will be transparent color when projected by the head-up display device.

[0073] In this embodiment, the distortion correction circuit may include a coordinate counter that counts pixel coordinates of the image data to be analyzed. The image analysis circuit may determine which of the multiple display areas each pixel of the image data to be analyzed belongs to based on the pixel coordinates output by the coordinate counter, and may determine which display area will be transparent based on the determination result.

[0074] According to this embodiment, the pixel coordinates output by the coordinate counter indicate the pixel coordinates of each pixel in the image data to be analyzed, so that the image analysis circuit can determine the display area among multiple display areas to which each pixel of the image data to be analyzed belongs based on the pixel coordinates.

[0075] In addition, in this embodiment, the image analysis circuit may determine whether each display area is a display area that will be a transparent color by determining whether the pixel data belonging to each display area of ​​the multiple display areas is transparent color data based on the pixel coordinates output by the coordinate counter and the pixel data of the image data to be analyzed at the pixel coordinates.

[0076] According to this embodiment, the image analysis circuit can determine the display area to which pixel coordinates belong and whether the pixel data at those pixel coordinates is transparent color data. This allows the image analysis circuit to determine whether each display area is a display area that will be transparent when projected by a head-up display device. Furthermore, according to this embodiment, the image data to be analyzed is input image data input to the distortion correction circuit or output image data output by the distortion correction circuit, and the pixel coordinates output by the coordinate counter included in the distortion correction circuit are used for image analysis. This allows the distortion correction circuit to perform distortion correction while the image analysis circuit controls the backlight through image analysis in parallel, eliminating or simplifying the need for time lag adjustment between HUD display and backlight control.

[0077] In this embodiment, the image data to be analyzed may be output image data. The distortion correction circuit may perform distortion correction by converting pixel coordinates output by the coordinate counter into reference coordinates on the input image data and outputting pixel data of the output image data at the pixel coordinates based on the pixel data of the input image data at the reference coordinates. The image analysis circuit may determine which of multiple display areas the pixel coordinates output by the coordinate counter belong to, and determine whether the display area determined to include the pixel coordinates is a display area that will be transparent based on the pixel data of the output image data at the pixel coordinates output by the distortion correction circuit.

[0078] According to this embodiment, backlight control is performed by image analysis based on pixel coordinates output by a coordinate counter used for distortion correction and pixel data of the output image data output by the distortion correction circuit corresponding to those pixel coordinates. This allows distortion correction and backlight control by image analysis to be processed in parallel, eliminating or simplifying the need for time lag adjustment between HUD display and backlight control.

[0079] In this embodiment, the image data to be analyzed may be input image data. The image analysis circuit may include a coordinate conversion circuit and a judgment circuit. The coordinate conversion circuit may convert pixel coordinates output by the coordinate counter into destination coordinates on the output image data. The judgment circuit may determine which of a plurality of display areas the destination coordinates belong to, and may determine whether the display area determined to include the destination coordinates is a display area that will be transparent, based on pixel data of the input image data at the pixel coordinates.

[0080] According to this embodiment, pixel coordinates of input image data input to the distortion correction circuit are counted and converted to destination coordinates on the output image data. Backlight control is then performed using image analysis based on the destination coordinates and the pixel data of the pixel coordinates in the input image data. This allows for parallel processing of distortion correction and backlight control using image analysis, eliminating or simplifying the need for time lag adjustment between HUD display and backlight control.

[0081] In this embodiment, the distortion correction circuit may include a correction coordinate counter that counts coordinates on the output image data, and may perform distortion correction based on a first coordinate transformation that converts the coordinates output by the correction coordinate counter into reference coordinates on the input image data. The coordinate transformation circuit may obtain destination coordinates by performing a second coordinate transformation, which is an inverse transformation of the first coordinate transformation, on the pixel coordinates output by the coordinate counter.

[0082] According to this embodiment, in addition to the correction coordinate counter used for reverse warp, a coordinate counter that counts pixel coordinates of input image data and a coordinate conversion circuit that converts the pixel coordinates into destination coordinates on output image data are provided. This makes it possible to determine whether the display area will be transparent when projected by the head-up display device, using the input image data as the image data to be analyzed.

[0083] In this embodiment, the circuit device may include a brightness control value calculation circuit and an interface circuit. The brightness control value calculation circuit may calculate a brightness control value for each of the plurality of light-emitting elements by modifying a backlight control signal received from an external processing device based on the result of backlight control processing from the image analysis circuit. The interface circuit may output the brightness control value for each light-emitting element to the backlight device.

[0084] According to this embodiment, it is possible to combine backlight control by an image analysis circuit with dimming control by an external processing device. Specifically, the dimming control by the external processing device is reflected on light-emitting elements that the image analysis circuit determines to be on through image analysis. Furthermore, light-emitting elements that the image analysis circuit determines to be off through image analysis are controlled to be off regardless of the dimming control by the external processing device. While a backlight device normally has a single control input, according to this embodiment, the dimming control by the processing device and the backlight control by the image analysis circuit can be combined and input to the single control input.

[0085] A head-up display device of the present embodiment includes any of the circuit devices described above, a display panel, and a backlight device.

[0086] Although the present 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 novel features and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure. For example, a term described at least once in the specification or drawings together with a different term having a broader or equivalent meaning may be replaced with that different term anywhere in the specification or drawings. Furthermore, all combinations of the present embodiment and modifications are also included within the scope of the present disclosure. Furthermore, the configurations and operations of the circuit device, display device, backlight device, etc. are not limited to those described in the present embodiment, and various modifications are possible. [Explanation of symbols]

[0087] 1...image, 2...display object, 5...display area, 6...display object, 10...backlight device, 20...display panel, 30...display device, 50...head-up display device, 100...circuit device, 110...distortion correction circuit, 112...coordinate counter, 113...coordinate conversion circuit for correction, 114...interpolation circuit, 115...memory circuit, 116...coordinate counter for correction, 119...distortion correction unit, 120...image analysis circuit, 121...coordinate conversion circuit, 122...judgment circuit, 130...output circuit, 140...interface circuit, 150...brightness control value calculation circuit, 160...interface circuit, 200...processing device, AR...display area, BHI...brightness variation correction amount, CTL...control signal, CTLB...control signal, GZA...reference coordinate, GZA2...pixel coordinate, GZB...pixel coordinate, GZB2...destination coordinate, IMA...input image data, IMB...output image data, KDI...brightness adjustment amount, LS...light-emitting element

Claims

1. A circuit device used in a head-up display device including a display panel and a backlight device having a plurality of light-emitting elements, a distortion correction circuit that performs distortion correction on input image data and outputs the distortion-corrected output image data; an image analysis circuit that analyzes the output image data and, based on the analysis result, performs backlight control processing to turn off light-emitting elements corresponding to display areas that will be transparent when projected by the head-up display device, among a plurality of display areas corresponding to the plurality of light-emitting elements on the display panel; Including, The distortion correction circuit a coordinate counter that counts pixel coordinates of the output image data, converting the pixel coordinates output by the coordinate counter into reference coordinates on the input image data, and outputting pixel data of the output image data at the pixel coordinates based on pixel data of the input image data at the reference coordinates, thereby performing the distortion correction; The image analysis circuit A circuit device characterized in that it determines which of the plurality of display areas the pixel coordinates output by the coordinate counter belong to, and determines whether the display area to which the pixel coordinates are determined to belong is a display area that will be the transparent color based on pixel data of the output image data at the pixel coordinates output by the coordinate counter.

2. 2. The circuit device according to claim 1, The image analysis circuit A circuit device characterized in that the backlight control process analyzes whether the output image data in each of the plurality of display areas is transparent color data, and turns off light-emitting elements corresponding to the display area where the output image data is analyzed to be transparent color data.

3. A circuit device used in a head-up display device including a display panel and a backlight device having a plurality of light-emitting elements, a distortion correction circuit that performs distortion correction on input image data and outputs the distortion-corrected output image data; an image analysis circuit that analyzes the input image data and, based on the analysis result, performs backlight control processing to turn off light-emitting elements corresponding to display areas that will be transparent when projected by the head-up display device, among a plurality of display areas corresponding to the plurality of light-emitting elements on the display panel; Including, The distortion correction circuit a storage circuit for temporarily storing the input image data; a coordinate counter that counts pixel coordinates of pixel data sequentially written into the memory circuit; Including, The distortion correction circuit performing the distortion correction on the input image data stored in the storage circuit; The image analysis circuit a coordinate conversion circuit that converts the pixel coordinates output by the coordinate counter into destination coordinates on the output image data; a determination circuit that determines which of the plurality of display areas the destination coordinates belong to, and determines whether the display area determined to include the destination coordinates is a display area that will be the transparent color, based on pixel data of the input image data at the pixel coordinates; A circuit device comprising:

4. 4. The circuit device according to claim 3, The image analysis circuit A circuit device characterized in that the backlight control process analyzes whether the input image data in each display area of ​​the plurality of display areas is transparent color data or not, and turns off light-emitting elements corresponding to the display area where the input image data is analyzed to be transparent color data.

5. 5. The circuit device according to claim 3, The distortion correction circuit a correction coordinate counter that counts coordinates on the output image data, and performs the distortion correction based on a first coordinate transformation that transforms the coordinates output by the correction coordinate counter into reference coordinates on the input image data; The coordinate conversion circuit a circuit device for determining the destination coordinates by performing a second coordinate transformation, which is an inverse transformation of the first coordinate transformation, on the pixel coordinates output by the coordinate counter;

6. 6. The circuit device according to claim 1, a brightness control value calculation circuit that calculates a brightness control value for each of the plurality of light-emitting elements by changing a backlight control signal received from an external processing device based on a result of the backlight control process from the image analysis circuit; an interface circuit that outputs the brightness control value for each of the light-emitting elements to the backlight device; A circuit device comprising:

7. A circuit arrangement according to any one of claims 1 to 6; the display panel; the backlight device; A head-up display device comprising:

Images