Display control system, circuit device, and display system

Abstract

To achieve proper local dimming control reflecting global dimming control in a processor.SOLUTION: A display control system 5 includes: a processor 200 that operates global lighting control information for global dimming control of a backlight 120 of a display 100, and performs color correction of image data on the basis of the global lighting control information; and a circuit arrangement 10 that performs display control of the display 100 on the basis of the image data from the processor 200. The circuit arrangement 10 includes: a lighting control circuit 50 that operates local lighting control information for local dimming control of the backlight 120 on the basis of the image data and the global lighting control information from the processor 200; and a light source control circuit 60 that performs light source control of the backlight 120 on the basis of the local lighting control information from the lighting control circuit 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a display control system, a circuit device, a display system, and the like. [Background Art]

[0002] In a display device, global dimming control is performed based on detection information from an external light sensor or the like. Patent Document 1 discloses a display device that performs local dimming control, which is dimming control for each of a plurality of light sources. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] International Publication No. 2021 / 241066 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, until now, no display control system that implements both global dimming control and local dimming control without significantly modifying existing systems has been proposed. [Means for Solving the Problem]

[0005] One aspect of the present disclosure relates to a display control system comprising: a processing device that calculates global dimming information for global dimming control of the backlight of a display device having a display panel and a backlight, and performs color correction of image data based on the global dimming information; and a circuit device that performs display control of the display device based on the image data from the processing device, wherein the circuit device comprises a dimming control circuit that calculates local dimming information for local dimming control of the backlight based on the image data from the processing device and the global dimming information, and a light source control circuit that performs light source control of the backlight based on the local dimming information from the dimming control circuit.

[0006] Other aspects of the present disclosure relate to a circuit device including: an interface circuit that receives global dimming information from a processing device that calculates global dimming information for global dimming control of a display device having a display panel and a backlight and performs color correction of image data based on the global dimming information; a dimming control circuit that calculates local dimming information for local dimming control of the backlight based on the image data from the processing device and the global dimming information; and a light source control circuit that performs light source control of the backlight based on the local dimming information from the dimming control circuit.

[0007] Other aspects of this disclosure relate to the display control system described above and the display system including the display device. [Brief explanation of the drawing]

[0008] [Figure 1] An example configuration of the display control system and circuit device of this embodiment. [Figure 2] Detailed configuration example of the display control system and circuit device of this embodiment. [Figure 3] Example configuration of backlight and display panel. [Figure 4] Diagram illustrating the light source and display area. [Figure 5] A flowchart illustrating a detailed example of the processing in this embodiment. [Figure 6] Diagram explaining color correction. [Figure 7] Diagram illustrating dimming control. [Figure 8] A detailed example of another configuration of the circuit device of this embodiment. [Figure 9] A detailed example of another configuration of the circuit device of this embodiment. [Figure 10] An example configuration of a head-up display, which is an example of the display system of this embodiment. [Modes for carrying out the invention]

[0009] Preferred embodiments of this disclosure will be described in detail below. These embodiments are not intended to unduly limit the scope of the claims, and not all configurations described in these embodiments are necessarily essential.

[0010] 1. Display control system, circuit device Figure 1 shows an example configuration of the display control system 5 and circuit device 10 of this embodiment. The display control system 5 includes a processing unit 200 and a circuit device 10. The circuit device 10 includes a dimming control circuit 50 and a light source control circuit 60. The display control system 5 is a system that controls the display of the display device 100.

[0011] The display device 100 displays an image based on image data. Taking a head-up display as an example, the display device 100 is a device for displaying a virtual image in the user's field of vision. The display device 100 is a display device used in, for example, a head-up display, but it may also be other automotive display devices such as a cluster display which is a display on the instrument panel, or it may be a display device for purposes other than automobiles. Hereafter, a head-up display will be referred to as a HUD as appropriate.

[0012] The display device 100 includes a display panel 110 and a backlight 120. The display panel 110 is, for example, an electro-optical panel. The display device 100 may also include a light source driver (not shown) for driving the light source of the backlight 120, a display controller (not shown), and a display driver (not shown) for driving the display panel 110. For example, the backlight 120 is provided with multiple light sources LS. Specifically, the backlight 120 has an array of multiple light sources LS, which are realized by LEDs or the like. The light source driver drives these multiple light sources LS to emit light. The display driver may include a data driver for driving the data lines of the display panel 110, a scan driver for driving the scan lines of the display panel 110, and so on.

[0013] The processing unit 200 is, for example, a System on Chip (SoC), also known as a master device. The processing unit 200 can be implemented as, for example, a microcomputer, CPU, or MPU. For example, the circuit device 10 is connected to the processing unit 200 via an interface circuit (not shown). Image data (IMI) from the processing unit 200 is then input to the circuit device 10 via the interface circuit.

[0014] The circuit device 10 is, for example, an integrated circuit device in which multiple circuit elements are integrated on a semiconductor substrate. The display device 100 displays an image based on the display image data from the circuit device 10. If the display device 100 is a HUD, then the circuit device 10 is a HUD controller.

[0015] The processing unit 200 then calculates global dimming information for global dimming control of the backlight 120 of the display device 100. The processing unit 200 also performs color correction of image data based on the global dimming information. The calculation of the global dimming information is performed by the global dimming control unit 210, and the color correction of image data is performed by the color correction unit 220. The global dimming control unit 210 and the color correction unit 220 can be implemented, for example, by a processor that implements the processing unit 200 or a program that runs on the processor.

[0016] For example, the processing device 200 performs global dimming control processing for the backlight 120 based on detection information from an external light sensor or the like. For example, when external light is bright, global dimming control processing is performed such as increasing the brightness of light from the light sources LS of the backlight 120, and decreasing the brightness of light from the light sources LS of the backlight 120 when external light is dark. Then, the processing device 200 calculates global dimming information DMG for such global dimming control. The global dimming information DMG is information on the dimming amount of the backlight 120 achieved by global dimming. For example, the global dimming information DMG is brightness correction information for the backlight 120 when correcting the brightness of the backlight 120 to be brighter or darker through global dimming. The processing device 200 outputs the calculated global dimming information DMG to the circuit device 10.

[0017] Furthermore, the processing device 200 performs color correction on image data and outputs image data IMI after color correction. For example, the processing device 200 performs color correction based on the global dimming information DMG calculated through global dimming, and outputs the image data IMI after color correction to the circuit device 10. For example, when the brightness of the backlight 120 changes due to global dimming, the hue of an image displayed on the display device 100 changes. For example, due to factors such as the color of the light sources of the backlight 120, the hue of the displayed image changes in accordance with changes in the brightness of the backlight 120. The processing device 200 performs color correction to suppress changes in the hue of the displayed image in accordance with changes in the brightness of the backlight 120, and outputs the image data IMI after color correction.

[0018] A dimming control circuit 50 of a circuit device 10 calculates local dimming information for local dimming control of a backlight 120 based on image data IMI and global dimming information DMG from a processing device 200. For example, the dimming control circuit 50 receives the global dimming information DMG and the image data IMI color-corrected based on the global dimming information DMG from the processing device 200, and calculates the local dimming information based on the image data IMI and the global dimming information DMG. The local dimming information is information on a dimming amount of the backlight 120 obtained by local dimming. For example, in a case where the backlight 120 includes a plurality of light sources, and each of the plurality of light sources is provided corresponding to each of a plurality of areas of a display panel 110, the local dimming information is information on a dimming amount of each light source of the backlight 120 in each of the plurality of areas. For example, the dimming control circuit 50 calculates information on the dimming amount of each light source of the backlight 120 in each area based on an analysis result of the image data IMI in each of the plurality of areas and luminance correction information that is the global dimming information DMG.

[0019] A light source control circuit 60 of the circuit device 10 performs light source control of the backlight 120 based on the local dimming information from the dimming control circuit 50. For example, the light source control circuit 60 performs light source control for causing a light source LS of the backlight 120 to emit light with a dimming amount set by the local dimming information. For example, in a case where a light source driver of the backlight 120 is provided in a display device 100, the light source control circuit 60 implements light source control of the backlight 120 by outputting luminance information for each area that is the local dimming information and a control signal for the light source driver to the light source driver. In a case where the light source control circuit 60 generates a PWM signal for the light source LS of the backlight 120, the light source control of the backlight 120 may be implemented by outputting this PWM signal.

[0020] The circuit device 10 outputs the display image data of the display device 100 to the display device 100. This display image data is image data that has undergone color correction based on local dimming information, in addition to the image data IMI that has undergone color correction based on global brightness information. The dimming control circuit 50 and the light source control circuit 60 are, for example, logic circuits. These logic circuits may be configured as separate circuits, or they may be configured as integrated circuits by automatic placement and routing, etc. Alternatively, some or all of these logic circuits may be implemented 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 that program or instruction set.

[0021] As described above, in this embodiment, the processing unit 200 calculates global dimming information for performing global dimming control. The processing unit 200 also performs color correction of image data based on the global dimming information. The dimming control circuit 50 of the circuit device 10 calculates local dimming information for performing local dimming control based on the image data from the processing unit 200 and the global dimming information, and the light source control circuit 60 controls the light source of the backlight 120 based on the local dimming information. In this way, a display control system 5 can be realized in which the processing unit 200 performs global dimming control and the circuit device 10 performs local dimming control that reflects this global dimming control. Therefore, without changing existing systems in which the processing unit 200 performs global dimming control, it becomes possible to implement dimming control that incorporates global dimming control into local dimming control, thereby enabling more appropriate dimming control of the display device 100.

[0022] For example, the display control system 5 of this embodiment consists of a processing unit 200 that performs global dimming control and outputs an image to a circuit device 10, and a circuit device 10 that performs local dimming control on the input image. The circuit device 10, such as a HUD controller, uses the image and brightness correction information input from the processing unit 200, which is the master device, as parameters to perform dimming control for each of the multiple areas. This makes it possible to display high-contrast images while coordinating with the global dimming control of the master device without significantly changing the existing system.

[0023] For example, previously, the master device received ambient light brightness via a sensor and output a signal to the light source driver to control the backlight brightness in order to improve the visibility of the display. Local dimming divides the backlight into areas and controls the dimming of each area, making it possible to output images with high contrast. Until now, HUD controllers have not been able to combine global dimming control of the master device with local dimming control.

[0024] For example, if only global dimming control is performed, a single brightness control is applied to the entire screen, resulting in visible backlight leakage along the display shape in low-light environments. This impairs the visibility of images displayed on the HUD and the driver's forward visibility. In conventional HUD display control systems, brightness information for global dimming control was input from the master device to the light source driver. Therefore, in order to send control signals to each light source driver to reflect the brightness information for each area, it was necessary to process the brightness information from the master device and convert it into a signal for local dimming.

[0025] In this embodiment, local dimming control is performed in the HUD controller (circuit device 10) using the image after global dimming and brightness correction information from the master device (processing device 200) as parameters, and brightness information and driver control signals are transmitted to each light source driver. In this way, backlight control is performed for each area, making it possible to display an image with clear contrasts on the projection target and suppressing light leakage in low-light environments. Furthermore, if there is an image with locally dark areas, the brightness of the backlight can be dimmed only for those areas, which also leads to a reduction in power consumption. Moreover, by simply incorporating the HUD controller between the master device, the display, and the light source driver, local dimming control in coordination with the master device's global dimming control can be achieved, making it possible to expand functionality without requiring major system changes.

[0026] 2. Detailed Configuration Example Figure 2 shows a detailed configuration example of the display control system 5 and circuit device 10 of this embodiment. In Figure 2, the circuit device 10 includes a distortion correction circuit 20, a color correction circuit 30, and interface circuits 40 and 70 in addition to the configuration in Figure 1. Note that the circuit device 10, processing unit 200, and display device 100 are not limited to the configuration example in Figure 2 or other configuration examples described later, and various modifications can be made, such as omitting some of these components, adding other components, or replacing some components with other components.

[0027] The processing unit 200 includes a global dimming control unit 210 and a color correction unit 220. The global dimming control unit 210 performs control processing for global dimming, and the color correction unit 220 corrects the color of the image. Specifically, the global dimming control unit 210 calculates global dimming information DMG for global dimming control of the backlight 120 of the display device 100 based on detection information from the ambient light sensor 250, and outputs the calculated global dimming information DMG to the circuit device 10. For example, if the ambient light detected by the ambient light sensor 250 is determined to be bright, the global dimming control unit 210 increases the brightness of the backlight 120, and if the ambient light is determined to be dark, it performs dimming processing to decrease the brightness of the backlight 120. The color correction unit 220 performs color correction of the image data based on the calculated global dimming information DMG, and outputs the color-corrected image data IMI to the circuit device 10. For example, when the global dimming control unit 210 performs brightness correction to make the backlight 120 brighter or darker, the color correction unit 220 performs color correction to suppress changes in the color of the displayed image due to the brightness correction of the backlight 120. The global dimming information DMG and image data IMI are output to the circuit device 10 via, for example, an interface circuit (not shown).

[0028] The display device 100 includes a display panel 110, a backlight 120, and a light source driver 130. Multiple light source drivers may be provided, with each light source group of the backlight 120 having its own light source driver. The display device 100 may also include a display driver (not shown) for driving the display panel 110.

[0029] Figure 3 shows an example configuration of the backlight 120 and the display panel 110. In Figure 3, direction D1 is the horizontal scanning direction of the display panel 110, and direction D2 is the vertical scanning direction of the display panel 110. Direction D3 is perpendicular to directions D1 and D2, and is the direction in which the display panel 110 is viewed from above. The backlight 120 is installed on the side of the display panel 110 in direction D3, and emits illumination light in the opposite direction to direction D3, which is the direction toward the display panel 110.

[0030] The backlight 120 includes multiple light sources LS. Figure 3 illustrates an example where 8 x 5 light sources LS are arranged in a two-dimensional array. That is, 8 light sources LS are arranged along direction D1, and 5 light sources LS are arranged along direction D2. For proper local dimming, it is desirable to provide, for example, 100 or more light sources LS in the backlight 120. The light sources LS are, for example, LEDs (Light Emitting Diodes). However, the light sources LS are not limited to LEDs; any light source whose light intensity can be independently controlled and which is close to a point source is acceptable. A light source that is close to a point source means that the size of the light-emitting part of the light source LS is sufficiently smaller than the area AR corresponding to that light source LS. Various arrangements of light sources LS are possible, such as square arrangement and hexagonal arrangement.

[0031] The display panel 110 has a pixel array, and the area on the pixel array where the display image is displayed is defined as the display area. The display area is divided into multiple areas AR. Each area AR is correspondingly positioned to a light source LS. That is, one light source LS corresponds to one area AR. For example, when the display panel 110 is viewed from above, the light source LS is positioned at the center of the area AR. However, the position of the light source LS is not limited to this. In Figure 3, the display area is divided into 8 × 5 areas AR corresponding to 8 × 5 light source LS. Note that the areas AR are used for processing in the circuit device 10, and there are no boundaries between the areas AR in the display image actually displayed on the display panel 110. The display panel 110 is a panel in which the transmittance of each pixel is controlled according to the display image, and the display image is displayed by each pixel transmitting illumination light from the backlight 120. The display panel 110 is, for example, a liquid crystal display panel.

[0032] Thus, when the display area of ​​the display panel 110 is divided into multiple areas such that each area AR has a light source LS, the light sources LS that illuminate the display panel 110 have a light intensity distribution such that the light intensity decreases as you move away from the light source LS. For this reason, the light intensity is lower in the peripheral areas of area AR than in the center. This light intensity distribution of the light sources LS is called the PSF. Figure 4 shows an example of the light intensity distribution of the PSF. In Figure 4, the light intensity distribution is shown as a gradient, and the whiter the area, the larger the coefficient of the light intensity distribution. In Figure 4, the size of the PSF corresponds to 3x3 areas AR1 to AR9, and the center of the PSF is located at the position of the light source.

[0033] As shown in Figure 2, the circuit device 10 includes a distortion correction circuit 20 and a color correction circuit 30. The distortion correction circuit 20 corrects the distortion of the image data IMI, which is the input image data from the processing device 200, and outputs the distortion-corrected image data IM. The color correction circuit 30 then performs color correction on the image data IM from the distortion correction circuit 20.

[0034] Specifically, the distortion correction circuit 20 performs distortion correction on the image data IMI using a coordinate transformation between the pixel coordinates in the image data IMI and the pixel coordinates in the image data IM, and outputs the result as image data IM. Distortion correction is the process of applying an image distortion to the image that is the opposite of the image distortion that occurs when the image displayed on the display panel 110 is projected, and is an image correction to make the HUD display distortion-free or reduced. Image distortion due to projection includes image distortion due to the curvature of the screen in the HUD, image distortion due to the HUD optical system, or both. For example, a HUD presents an image to the user by projecting the image onto a transparent screen or by displaying the image on a transparent display panel. At this time, by deforming the image to match the curvature of the transparent screen or transparent display panel, the user can see an image without distortion. The distortion correction circuit 20 performs this image deformation process as distortion correction.

[0035] For example, the distortion correction circuit 20 performs reverse mapping or forward mapping. Reverse mapping, also known as reverse warp, is a mapping process that transforms the pixel coordinates in the output image data IM to their corresponding reference coordinates, and then obtains the pixel data of the image data IM from the pixel data of the image data IM at those reference coordinates. Forward mapping, also known as forward warp, is a mapping process that transforms the pixel coordinates in the image data IM to their corresponding destination coordinates, and then obtains the pixel data of the image data IM at the destination coordinates from the pixel data of the image data IM at the pixel coordinates. The coordinate transformations in reverse mapping and forward mapping are defined by mapping parameters, also known as map data. Mapping parameters include a table that associates coordinates on the input image with coordinates on the output image, a table that shows the amount of movement between the coordinates on the input image and the coordinates on the output image, or the coefficients of a polynomial that associates coordinates on the input image and the coordinates on the output image.

[0036] The color correction circuit 30 performs color correction on the image data IM and outputs the display image data IMD to the display device 100. In other words, the color correction circuit 30 performs color correction on the image data IM and outputs the color-corrected image data IM as the display image data IMD to the display device 100. Color correction is, for example, a color adjustment process for the image data IM, and is a correction process that adjusts the color levels. Color correction can also be called brightness correction or gradation correction of the image data IM.

[0037] For example, when dimming control is performed when displaying image data IMD on the display device 100, the color correction circuit 30 performs color correction on the image data IM according to the amount of dimming in this dimming control. Dimming control is a control that adjusts the amount of light from a light source device such as a backlight. Dimming control can be local dimming control, which controls the brightness of a light source device such as a backlight for each of multiple areas, or global dimming control, which controls the brightness of the entire display screen. In dimming control, control is performed to reduce the light output of the light source device in order to reduce the power consumption of the light source device and to make black pixels appear blacker. In this case, the color correction circuit 30 performs color correction to increase the brightness of the pixels corresponding to the light source on the display screen of the display device 100 by the amount by which the light output of the light source has been reduced. For example, the color correction circuit 30 performs color correction on each pixel value of the image data IM so that the image displayed on the display device 100 based on the display image data IMD has the same brightness and color tone as the image data IM, and outputs the color-corrected image data IM to the display device 100 as display image data IMD. The color correction performed by the color correction circuit 30 is not limited to color correction for compensating for such dimming control, but may also be color correction for adjusting the hue of the display image of the display device 100.

[0038] The interface circuit 40 is a circuit that performs interface processing with the processing unit 200, and is, for example, a host interface circuit. For example, global dimming information DMG calculated in the processing unit 200 is received from the processing unit 200 via the interface circuit 40. The brightness correction information, which is the received global dimming information DMG, is stored in a register (not shown).

[0039] The interface circuit 70 is a circuit that performs interface processing with the display device 100. For example, brightness information, which is local dimming information DML for each of the multiple areas, is output to the light source driver 130 of the display device 100 via the interface circuit 70. The interface circuit 70 also outputs control signals for the light source driver 130.

[0040] Furthermore, a processing unit such as an MCU may be provided between the light source control circuit 60 and the light source driver 130 to absorb differences in communication protocols depending on the model of the light source driver 130. In this case, the light source control circuit 60 will control the light source driver 130 via this processing unit such as the MCU. Also, the interface circuits 40 and 70 may be implemented as a single interface circuit. The distortion correction circuit 20, color correction circuit 30, dimming control circuit 50, light source control circuit 60, and interface circuits 40 and 70 are logic circuits. These logic circuits may be configured as separate circuits, or as an integrated circuit by automatic placement and routing, etc. Alternatively, some or all of these logic circuits may be implemented by a processor such as a DSP. 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 that program or instruction set.

[0041] The dimming control circuit 50 controls the dimming of the light source based on the image data IM. Specifically, the dimming control circuit 50 controls the dimming of the backlight 120, which has multiple light sources, and realizes a type of dimming control called local dimming. For example, the dimming control circuit 50 performs calculation processing to obtain information on the amount of dimming based on the image data IM. The information on the amount of dimming here is information for specifying the brightness at which the light source is illuminated by the dimming control. The light source control circuit 60 performs control processing and instruction processing for the light source driver 130 of the display device 100 based on the information on the amount of dimming from the dimming control circuit 50. The light source driver 130, which is an LED driver, then drives the light source LS of the backlight 120 based on the information on the amount of dimming, thereby realizing the dimming control of the backlight 120. For example, local dimming is realized in which dimming control is performed for each of the multiple areas into which the display area of ​​the display panel 110 is divided.

[0042] In this embodiment, the dimming control circuit 50 performs a luminance analysis of the image data IM and calculates local dimming information DML based on the luminance analysis results and global dimming information DMG.

[0043] In this way, local dimming information DML is calculated according to the brightness analysis results of the image data IM, and the backlight 120 is dimmed by the amount of dimming corresponding to this local dimming information DML, thereby realizing local dimming control. In this embodiment, in addition to the brightness analysis results of the image data IM, the local dimming information DML is calculated based on the global dimming information DMG from the processing unit 200 that performs global dimming control. Therefore, it becomes possible to dim the backlight 120 in a way that reflects the global dimming control by the processing unit 200 in addition to the local dimming control performed by the circuit device 10. As a result, without changing the existing system in which the processing unit 200 performs global dimming control, it becomes possible to perform local dimming control in addition to global dimming control, and more appropriate dimming control of the display device 100 can be realized.

[0044] Specifically, in this embodiment, as explained in Figures 3 and 4, the backlight 120 has multiple light sources LS, and each light source of the multiple light sources LS is provided corresponding to each area AR of the display panel 110. The dimming control circuit 50 performs a brightness analysis of the image data IM in each area, and based on the results of the brightness analysis in each area and the global dimming information DMG, calculates the amount of dimming for each light source corresponding to each area as local dimming information DML.

[0045] In this way, the brightness of the light source LS corresponding to each of the multiple areas AR of the display panel 110 can be controlled based on the results of brightness analysis of the image data IM in each area, thereby realizing local dimming control. In this embodiment, in addition to the results of brightness analysis of the image data IM in each area, local dimming information DML is calculated based on global dimming information DMG from the processing device 200 that performs global dimming control. Therefore, it becomes possible to control the dimming of the backlight 120 in a way that reflects the global dimming control by the processing device 200 in relation to the local dimming control performed by the circuit device 10, thereby realizing more appropriate dimming control of the display device 100.

[0046] As shown in Figure 2, the circuit device 10 also includes a color correction circuit 30 that performs color correction on the image data IM based on the image data IM and local dimming information DML. For example, the color correction circuit 30 performs color correction in accordance with the dimming control of the backlight 120 based on the dimming amount information, which is the local dimming information DML from the dimming control circuit 50. For example, if dimming control is performed to reduce the amount of light from the light source in an area corresponding to the light source, the color correction circuit 30 performs color correction to increase the brightness of the pixels in that area by the amount by which the amount of light from the light source in that area has been reduced, and outputs the color-corrected display image data IMD to the display device 100. As a result, the amount of light from the light source in that area can be reduced, and the image corresponding to the original image data IM can be displayed in that area based on the color-corrected display image data IMD, thereby realizing local dimming. As a result, it becomes possible to reduce the power consumption of the backlight 120 and display images in a way that makes black pixels appear blacker.

[0047] The circuit device 10 also includes a distortion correction circuit 20 that performs distortion correction on the image data IMI from the processing device 200. The color correction circuit 30 then performs color correction based on the distortion-corrected image data IM and the local dimming information DML.

[0048] By providing such a distortion correction circuit 20, it becomes possible to correct the image distortion by applying an image distortion that is the opposite of the image distortion caused by the curved surface of the screen on which the display image of the display panel 110 is projected. As a result, the user will see an image without distortion. Then, by performing color correction based on the distortion-corrected image data IM and local dimming information DML, it becomes possible to achieve appropriate local dimming control based on the distortion-corrected image data IM.

[0049] In Figure 2, the processing unit 200 performs global dimming control based on detection information from the ambient light sensor 250. For example, the ambient light sensor 250 detects the brightness of ambient light, and the global dimming control unit 210 of the processing unit 200 performs global dimming control based on this detection result and calculates global dimming information DMG.

[0050] In this way, global dimming control can be achieved, such as brightening or dimming the backlight 120 in response to the brightness of the ambient light. Then, while the processing unit 200 performs global dimming control using the detection information of the ambient light sensor 250, the circuit device 10 can perform local dimming control based on the analysis results of the image data IMI. Since the circuit device 10 performs local dimming control based on the analysis results of the image data IMI and the global dimming information DMG from the processing unit 200, it becomes possible to achieve local dimming control that reflects the global dimming control using the ambient light sensor 250 by the processing unit 200.

[0051] As shown in Figure 2, the display device 100 also includes a light source driver 130 that drives the light source of the backlight 120. The light source control circuit 60 of the circuit device 10 outputs backlight dimming information based on local dimming information DML to the light source driver 130. For example, the light source control circuit 60 outputs the brightness information for each area of ​​the backlight 120, which is local dimming information DML, as backlight dimming information, or it outputs a PWM signal as backlight dimming information, as will be described later.

[0052] In this configuration, the processing unit 200 performs global dimming control and outputs global dimming information DMG and image data IMI to the circuit device 10. The circuit device 10 then outputs backlight dimming information based on local dimming information DML calculated from the image data IMI and global dimming information DMG to the light source driver 130. This allows the processing unit 200 to perform global dimming control, the circuit device 10 to perform local dimming control, and the light source driver 130 to drive local dimming that reflects global dimming. Consequently, it becomes possible to achieve local dimming with minimal changes to the existing system.

[0053] 3. Dimming control Next, the details of the dimming control circuit 50 will be described. As shown in Figure 2, the dimming control circuit 50 includes a luminance analysis unit 52, a luminance calculation unit 54, and a dimming amount calculation unit 56. The luminance analysis unit 52 performs luminance analysis of the image data IM. The luminance calculation unit 54 performs luminance calculation processing based on the luminance analysis result from the luminance analysis unit 52 and the global dimming information DMG. The dimming amount calculation unit 56 performs processing to calculate local dimming information based on the luminance calculation result from the luminance calculation unit 54. Specifically, the luminance analysis unit 52 searches for the pixel with the maximum luminance in each of the multiple areas of the display area based on the image data IM. The luminance calculation unit 54 performs a correction by multiplying the maximum luminance of the searched pixel by the luminance correction value of the global dimming information DMG. The dimming amount calculation unit 56 then determines the luminance distribution for each light source so that the color with the maximum luminance multiplied by the luminance correction value can be displayed. Based on the determined luminance distribution of the light sources and the diffusion coefficient information of the light sources, it performs a calculation process to recalculate the luminance for each pixel and calculates the dimming amount corresponding to the luminance value of the backlight 120 for each pixel. The diffusion coefficient information is, for example, the diffusion coefficient parameter information of the diffuser plate 115 shown in Figure 10, which will be described later. The dimming amount information from the dimming amount calculation unit 56 is sent to the light source driver 130 via the light source control circuit 60, and the light source driver 130 drives the light sources in each of the multiple areas to emit light according to the dimming amount, thereby realizing local dimming.

[0054] Next, a specific example of the processing in this embodiment will be described. Figure 5 is a flowchart illustrating a detailed example of the processing in this embodiment.

[0055] First, the processing unit 200 performs global dimming control based on the detection information from the ambient light sensor 250 and calculates global dimming information DMG (step S1). The processing unit 200 also performs color correction of the image data based on the global dimming information DMG (step S2). Then, the circuit device 10 receives the color-corrected image data IMI and global dimming information DMG from the processing unit 200 (step S3). By receiving this image data IMI and global dimming information DMG, the circuit device 10 can perform local dimming control that reflects the global dimming control of the processing unit 200.

[0056] Next, the dimming control circuit 50 performs a luminance analysis of the image data IMI and searches for the pixel with the maximum luminance in each area of ​​each light source (step S4). For example, in each area corresponding to each light source as explained in Figures 3 and 4, the luminance of the pixels present in that area is searched based on the image data IM, and the pixel with the maximum luminance in that area is found. Then the dimming control circuit 50 performs a correction by multiplying the maximum luminance of the searched pixel by the luminance correction value of the global dimming information DMG (step S5). Then the dimming control circuit 50 determines the luminance distribution for each light source so that the color of the pixel with the maximum luminance can be displayed (step S6). The maximum luminance here is the corrected maximum luminance obtained by multiplying the maximum luminance of the searched pixel by the luminance correction value, but below it will simply be referred to as the maximum luminance. For example, suppose the luminance range is 0 to 100, and the luminance of the pixel with the maximum luminance in the target area is 50. In this case, the luminance distribution of the light sources is determined so that the pixel with the maximum luminance of 50 can be displayed with the color of, for example, the upper limit of the luminance range, which is 100. If the brightness of the pixel with the highest brightness is at the upper limit of the brightness range, then it is guaranteed that the brightness of the other pixels will fall within the brightness range of 0 to 100. The dimming control circuit 50 then recalculates the brightness for each pixel of the display panel 110 based on the diffusion coefficient information (step S7). This determines the brightness value of the backlight 120 for each pixel.

[0057] For example, as shown in Figure 10 described later, the display device 100 has a diffuser plate 115 installed between the backlight 120 and the display panel 110 to diffuse the light from the light source and create a uniform brightness distribution. The diffuser plate 115 is also called a diffuser sheet. For example, as shown in Figure 4, the light intensity distribution PSF of the light source has an intensity distribution where the light intensity decreases as you move away from the light source, but by providing a diffuser plate 115 and diffusing the light from the light source, brightness unevenness can be reduced and a uniform surface light source can be realized. Here, there are various methods of light diffusion, such as direct-lit, side-lit, and edge-lit methods. Then, in step S7 of Figure 5, the brightness of each pixel of the display panel 110 is recalculated by taking into account the light intensity distribution PSF of the light source in Figure 4 as well as the diffusion of light from the light source by the diffuser plate 115, and the brightness value of the backlight 120 for each pixel is obtained. For example, for a given pixel, the brightness is recalculated by determining the light intensity from, for example, 4x4 LED light sources surrounding that pixel, based on the light intensity distribution PSF in Figure 4 and the diffusion coefficient information of the diffuser plate 115, thereby determining the brightness value of the backlight 120 for each pixel. In this way, it becomes possible to appropriately determine the brightness value of the backlight 120 for each pixel in a display device 100 having a backlight 120 with multiple light sources and a diffuser plate 115.

[0058] Figure 6 is an explanatory diagram of an example of color correction processing. First, as explained in Figure 5, the luminance B of the backlight 120 of the target pixel is determined. A luminance-coefficient table is stored in a memory circuit (not shown) of the circuit device 10, and a coefficient K is calculated from the luminance B of the backlight 120 using this table. The luminance-coefficient table in Figure 6 is such that the coefficient K increases as the luminance B decreases. Alternatively, the coefficient K may be determined from the luminance B based on a predetermined calculation formula instead of using such a luminance-coefficient table. The luminance-coefficient table in Figure 6 has a first-order characteristic, but is not limited to this; an appropriate characteristic corresponding to the characteristics of the human eye in relation to light brightness should be used. The coefficient K may also be obtained by interpolating the two output values ​​of the luminance-coefficient table using first-order interpolation or spline interpolation. Then, the color level to be output to the display device 100 is determined by multiplying the coefficient K obtained in this way by the color level C of the target pixel. That is, for pixels with low luminance B of the backlight 120, a process is performed to increase the color level of the image data. In this way, the color correction circuit 30 can obtain the display image data IMD from the image data IM and output it to the display device 100. In the brightness-coefficient table in Figure 6, the coefficient K increases as the brightness B of the backlight 120 decreases. Therefore, as the brightness of the backlight 120 for the target pixel decreases, the color level of the target pixel increases, enabling dimming control.

[0059] Figure 7 is an explanatory diagram of the dimming control in this embodiment. The luminance analysis unit 52 receives the color C of the target pixel as image data, performs luminance analysis for each area, searches for the pixel with the maximum luminance in each area, and outputs the maximum luminance B for each area. The luminance B is, for example, a value in the range of 0 to 255.

[0060] The luminance calculation unit 54 receives the luminance B and the luminance correction value G, which is the luminance correction information for global dimming. The luminance correction value G is a value in the range of 0 to 1, where "0" corresponds to 0% and "1" corresponds to 100%. The luminance calculation unit 54 then multiplies the luminance B by the luminance correction value G and outputs B × G. By performing this multiplication process, local dimming control that reflects global dimming control can be realized. The dimming amount calculation unit 56 receives B × G and the diffusion coefficient value σ, which is the diffusion coefficient information, and outputs B × G × σ. The color correction circuit 30 receives B × G × σ and the image data of color C, and outputs C × (255 / B × G × σ). This realizes the color correction explained in Figure 6. If the calculation result of C × (255 / B × G × σ) exceeds 255, it is treated as 255.

[0061] As shown in Figure 7, the system searches for the pixel with the maximum brightness B in each area of ​​the image data, and then multiplies that brightness B by the brightness correction value of global dimming. It also multiplies it by the diffusion coefficient value σ. Based on the obtained B × G × σ, color correction C of the image data is performed, and C × (255 / B × G × σ) is output. This enables proper color correction. Furthermore, since the brightness of each light source of the backlight 120 is determined by multiplying the maximum brightness B in each area by the brightness correction value G of global dimming, it becomes possible to realize local dimming control that reflects global dimming control.

[0062] 4. Other configuration examples Figures 8 and 9 show other configuration examples of the display control system 5 and circuit device 10 of this embodiment. For example, in Figure 2, the light source control circuit 60 output information for the light source driver 130 to generate a PWM signal as backlight dimming information to the light source driver 130. In contrast, in Figure 8, a circuit for generating a PWM signal is provided in the light source control circuit 60, and this circuit outputs the PWM signal to the display device 100. This PWM signal is a signal whose pulse width is set based on brightness information, which is the dimming amount information of the light source of the backlight 120. For example, the light source driver 130 buffers the PWM signal from the light source control circuit 60 and drives the light source of the backlight 120, such as an LED. Alternatively, the light source control circuit 60 may directly drive the light source of the backlight 120 without providing a light source driver 130.

[0063] Furthermore, while Figure 2 shows the processing unit 200 performing global dimming control based on detection information from the ambient light sensor 250, Figure 9 shows the processing unit 200 performing global dimming control based on detection information of the headlight on / off status. That is, the processing unit 200 performs global dimming control based on detection information of the headlight on / off status of a moving object such as a car equipped with the display control system 5. For example, when the headlights are turned on or off in response to the brightness of the surrounding environment, the processing unit 200 performs global dimming control based on the on / off detection information. For example, when the headlights are turned on, such as when it becomes night or when entering a tunnel, the processing unit 200 can determine that the surrounding environment has become dark, and therefore performs global dimming control, for example, by reducing the brightness of the backlight 120. On the other hand, when the headlights are turned off, such as when it becomes morning or daytime or when exiting a tunnel, the processing unit 200 can determine that the surrounding environment has become bright, and therefore performs global dimming control, for example, by increasing the brightness of the backlight 120. Note that the on / off status of the headlights may be performed automatically using a sensor, or the driver of the car may manually turn the headlights on and off.

[0064] 5. Display System Figure 10 shows an example configuration of a head-up display 190 as an example of the display system of this embodiment. The head-up display 190, which is the display system of this embodiment, includes the display control system 5 and the display device 100 of this embodiment. Note that the display control system 5 may be configured without the processing unit 200. The display device 100 displays a display image based on the display image data IMD from the circuit device 10. In the case of the display system of the head-up display 190, the display device 100 displays a virtual image to the user by projecting the display image. For example, the display device 100 includes a display panel 110 and a backlight 120. The display device 100 may also include a display driver 140 that drives the display panel 110 and a diffuser plate 115 provided between the display panel 110 and the backlight 120. The display device 100 may also include a projection optical system such as a mirror 150 that reflects the projection light of the projected image.

[0065] The display driver 140 drives the data lines and scan lines of the display panel 110 to display an image based on the display image data (IMD) from the circuit device 10. The light emitted by the backlight 120 passes through the diffuser plate 115 and the display panel 110, and is reflected by the mirror 150 towards the transparent screen 160. The transparent screen 160 is, for example, a car windshield. The reflective surface of the transparent screen 160 is, for example, concave, so that the projected image appears as a virtual image to the user. That is, to the user, the projected image appears to be focused further away than the transparent screen 160. This allows the projected image to be displayed within the background.

[0066] The display system of this embodiment is not limited to the configuration shown in Figure 10, and various modifications are possible. For example, a display panel other than a liquid crystal display panel may be used as the display panel 110, and the arrangement of the diffuser plate 115 and projection optical system can also be modified in various ways. Furthermore, the display system of this embodiment is not limited to the head-up display 190 shown in Figure 10, but may be other automotive display systems such as cluster displays, or even non-automotive display systems.

[0067] As described above, the display control system of this embodiment includes a processing unit that calculates global dimming information for global dimming control of the backlight of a display device having a display panel and a backlight, and performs color correction of image data based on the global dimming information, and a circuit device that performs display control of the display device based on the image data from the processing unit. The circuit device includes a dimming control circuit that calculates local dimming information for local dimming control of the backlight based on the image data from the processing unit and the global dimming information, and a light source control circuit that performs light source control of the backlight based on the local dimming information from the dimming control circuit.

[0068] In this embodiment, the processing unit calculates global dimming information and performs color correction of image data based on the global dimming information, the dimming control circuit of the circuit device calculates local dimming information based on the image data and global dimming information, and the light source control circuit controls the backlight based on the local dimming information. In this way, the processing unit performs global dimming control, and the circuit device can perform local dimming control that reflects this global dimming control. Therefore, without changing existing systems in which the processing unit performs global dimming control, it becomes possible to achieve dimming control that incorporates global dimming control into local dimming control, thereby realizing appropriate dimming control of the display device.

[0069] In this embodiment, the dimming control circuit may perform luminance analysis of the image data and calculate local dimming information based on the results of the luminance analysis and global dimming information.

[0070] In this way, local dimming information is calculated according to the results of the brightness analysis of the image data, and the backlight is dimmed by the amount of dimming according to this local dimming information, thereby enabling local dimming control that reflects the global dimming control in the processing unit.

[0071] In this embodiment, the backlight may have multiple light sources, with each of the multiple light sources corresponding to each of the multiple areas of the display panel. The dimming control circuit may perform brightness analysis of the image data in each area, and based on the results of the brightness analysis in each area and the global dimming information, calculate the amount of dimming for each light source corresponding to each area as local dimming information.

[0072] In this way, the amount of dimming for the light source corresponding to each of the multiple areas of the display panel can be controlled based on the results of the brightness analysis of the image data in each area and global dimming information, enabling local dimming control that reflects the global dimming control in the processing unit.

[0073] In this embodiment, the circuit device may also include a color correction circuit that performs color correction on the image data based on the image data and local dimming information.

[0074] In this way, it becomes possible to perform color correction in accordance with the dimming control of the backlight based on local dimming information from the dimming control circuit.

[0075] In this embodiment, the circuit device may include a distortion correction circuit that performs distortion correction on image data from the processing device, and the color correction circuit may perform color correction based on the distortion-corrected image data and local dimming information.

[0076] In this way, distortion correction is possible by applying an image distortion to the display panel that is the opposite of the image distortion caused by the projection surface onto which the displayed image is projected. Then, by performing color correction based on the distortion-corrected image data and local dimming information, it becomes possible to achieve appropriate local dimming control based on the distortion-corrected image data.

[0077] In this embodiment, the processing device may also perform global dimming control based on detection information from the ambient light sensor.

[0078] This approach enables global dimming control, such as adjusting the brightness of the backlight according to the ambient light conditions.

[0079] In this embodiment, the processing unit may also perform global dimming control based on detection information of the on / off status of the headlights of a moving object equipped with a display control system.

[0080] In this way, for example, if the headlights are turned on or off in response to the brightness of the surrounding environment, the processing unit can perform global dimming control based on the detection information of that on / off state.

[0081] In this embodiment, the display device also includes a light source driver that drives the backlight light source, and the light source control circuit of the circuit device may output backlight dimming information based on local dimming information to the light source driver.

[0082] In this way, the processing unit performs global dimming control and outputs global dimming information and image data to the circuit device, and the circuit device outputs backlight dimming information based on local dimming information calculated from the image data and global dimming information to the light source driver.

[0083] The circuit device of this embodiment also includes an interface circuit that receives global dimming information from a processing device that calculates global dimming information for global dimming control of a display device having a display panel and a backlight, and performs color correction of image data based on the global dimming information. The circuit device also includes a dimming control circuit that calculates local dimming information for local dimming control of the backlight based on image data from the processing device and the global dimming information, and a light source control circuit that controls the light source of the backlight based on the local dimming information from the dimming control circuit.

[0084] In this way, the processing unit performs global dimming control, and the circuit device performs local dimming control that reflects this global dimming control. Therefore, without modifying existing systems in which the processing unit performs global dimming control, it becomes possible to achieve dimming control that incorporates global dimming control into local dimming control, thereby realizing appropriate dimming control of the display device.

[0085] Furthermore, the display system of this embodiment includes the display control system described above and a display device.

[0086] 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 the display control system, circuit device, display device, display system, head-up display, etc., are not limited to those described in this embodiment, and various modifications are possible. [Explanation of Symbols]

[0087] 5…Display control system, 10…Circuit device, 20…Distortion correction circuit, 30…Color correction circuit, 40…Interface circuit, 50…Dimming control circuit, 52…Brightness analysis unit, 54…Brightness calculation unit, 56…Dimming amount calculation unit, 60…Light source control circuit, 70…Interface circuit, 100…Display device, 110…Display panel, 115…Diffuser plate, 120…Backlight, 130…Light source driver, 140…Display driver, 150…Mirror, 160…Transparent screen, 190…Head-up display, 200…Processing device, 210…Global dimming control unit, 220…Color correction unit, 250…Ambient light sensor, AR, AR1~AR9…Area, B…Brightness, C…Color, DMG…Global dimming information, DML…Local dimming information, G…Brightness correction value, IM, IMI…Image data, IMD…Display image data, LS…Light source, σ…Diffusion coefficient value

Claims

1. A processing device that calculates global dimming information for global dimming control of the backlight of a display device having a display panel and a backlight, and performs color correction of image data based on the global dimming information, A circuit device that controls the display of the display device based on the image data from the processing device, Includes, The aforementioned circuit device is A dimming control circuit calculates local dimming information for local dimming control of the backlight based on the image data from the processing device and the global dimming information, A light source control circuit that controls the light source of the backlight based on the local dimming information from the dimming control circuit, Includes, The aforementioned processing apparatus is Based on detection information from an ambient light sensor, if the ambient light detected by the ambient light sensor is determined to be bright, the brightness of the backlight is increased, and if the ambient light is determined to be dim, dimming processing is performed to decrease the brightness of the backlight. Alternatively, based on detection information of the on / off status of the headlights of a mobile body equipped with a display control system, if the headlights are turned on, the brightness of the backlight is decreased as it is determined that the surrounding environment has become dark, and dimming processing is performed as it is determined that the surrounding environment has become bright as it is determined that the headlights have become bright, thereby calculating the global dimming information, and outputting the global dimming information calculated by the dimming processing and the image data color-corrected based on the global dimming information to the circuit device. The dimming control circuit is, A display control system characterized by calculating local dimming information based on the global dimming information calculated by the dimming process of the processing device and the image data that has been color-corrected based on the global dimming information calculated by the dimming process.

2. In the display control system described in claim 1, The dimming control circuit is, A display control system characterized by performing a brightness analysis on the image data and calculating the local dimming information based on the results of the brightness analysis and the global dimming information.

3. In the display control system described in claim 2, The backlight has multiple light sources, Each of the multiple light sources is provided corresponding to each of the multiple areas of the display panel. The dimming control circuit is, A display control system characterized by performing a luminance analysis on the image data in each of the aforementioned areas, and calculating the amount of dimming for each light source corresponding to each of the aforementioned areas as local dimming information, based on the results of the luminance analysis in each of the aforementioned areas and the global dimming information.

4. In a display control system according to any one of claims 1 to 3, The aforementioned circuit device is A display control system characterized by including a color correction circuit that performs color correction on the image data based on the image data and the local dimming information.

5. In the display control system described in claim 4, The aforementioned circuit device is The processing device includes a distortion correction circuit that performs distortion correction on the image data from the processing device, The aforementioned color correction circuit is A display control system characterized by performing color correction based on the image data on which distortion correction has been performed and the local dimming information.

6. In a display control system according to any one of claims 1 to 3, The aforementioned display device is Includes a light source driver that drives the light source of the backlight, The light source control circuit of the aforementioned circuit device is A display control system characterized by outputting backlight dimming information based on the local dimming information to the light source driver.

7. An interface circuit that receives global dimming information from a processing device that calculates global dimming information for global dimming control of a display device having a display panel and backlight, and performs color correction of image data based on the global dimming information, A dimming control circuit calculates local dimming information for local dimming control of the backlight based on the image data from the processing device and the global dimming information, A light source control circuit that controls the light source of the backlight based on the local dimming information from the dimming control circuit, Includes, The aforementioned processing apparatus is Based on detection information from the ambient light sensor, if the ambient light detected by the ambient light sensor is determined to be bright, the brightness of the backlight is increased, and if the ambient light is determined to be dark, dimming processing is performed to decrease the brightness of the backlight. Alternatively, based on detection information of the on / off status of the headlights of a moving object equipped with a display control system, if the headlights are turned on, the brightness of the backlight is decreased as it is determined that the surrounding environment has become dark, and dimming processing is performed as it is determined that the surrounding environment has become bright as it is determined that the surrounding environment has become bright, thereby calculating the global dimming information, and outputting the global dimming information calculated by the dimming processing and the image data color-corrected based on the global dimming information to the interface circuit. The dimming control circuit is, A circuit device characterized by calculating local dimming information based on the global dimming information calculated by the dimming process of the processing device and the image data that has been color-corrected based on the global dimming information calculated by the dimming process.

8. A display control system according to any one of claims 1 to 3, A display system characterized by including the aforementioned display device.

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