Display device

Abstract

To provide a display device capable of reducing an amount of data of a command signal related to lighting control of a light source.SOLUTION: A display device 1 includes a liquid-crystal-type display panel 5 having a display surface 51 on which an image B is displayed; a plurality of light sources L1 to Ln arranged along the display surface 51 to illuminate the display panel 5; a driver 4d that drives the plurality of light sources L1 to Ln; and a control unit 2 that performs light emission control on the plurality of light sources L1 to Ln by outputting a dimming command signal J to the driver 4d and performs local dimming control for adjusting luminance for each of a plurality of regions into which the display surface 51 is divided by the light emission control. In the dimming command signal J, pieces of information relating to the luminance of each of the plurality of regions are arranged in order; information relating to a region where the luminance is greater than zero is included; and information relating to a region where the luminance is zero is omitted.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a display device. [Background technology]

[0002] The display device described in Patent Document 1 above includes a light source having a plurality of light-emitting elements arranged therein, a display unit arranged on the optical path of light from the light source and displaying an image, and a control unit that determines which areas of the plurality of light-emitting elements will emit light and causes the determined areas to emit light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-110816 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, the amount of data relating to the command signal from the control unit to the light source remains the same regardless of the content of the image, and there has been a demand for reducing this amount of data.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a display device that can reduce the amount of data in a command signal related to lighting control of a light source. [Means for solving the problem]

[0006] In order to achieve the above object, the display device according to the present disclosure comprises: a liquid crystal display panel having a display surface for displaying an image; a plurality of light sources arranged along the display surface for illuminating the display panel; a driver that drives the plurality of light sources; a control unit that outputs a dimming command signal to the driver to control the light emission of the plurality of light sources, and performs local dimming control to adjust the brightness of each of the plurality of regions into which the display surface is partitioned by this light emission control; The dimming command signal includes information relating to the brightness of each of the plurality of regions arranged in order, includes information relating to the regions whose brightness is greater than zero, and omits information relating to the regions whose brightness is zero. [Effects of the Invention]

[0007] According to the present disclosure, the amount of data of a command signal related to lighting control of a light source can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a display device according to an embodiment of the present disclosure. [Figure 2] 1 is a block diagram of a display device according to an embodiment of the present disclosure. [Figure 3] 1 is a schematic cross-sectional view of a display device according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram of an image according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is a diagram showing the dimming rate of each region obtained by dividing a display surface according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is a diagram conceptually illustrating mapping data according to an embodiment of the present disclosure. [Figure 7] FIG. 2 is a schematic diagram illustrating the arrangement of light sources relative to a display surface according to an embodiment of the present disclosure. [Figure 8] 10 is a flowchart illustrating a procedure for a local dimming control process according to an embodiment of the present disclosure. [Figure 9] FIG. 10 is a schematic diagram showing the arrangement of light sources relative to a display surface according to a modified example of the present disclosure. [Figure 10] FIG. 10 is a schematic diagram of an image according to a modified example of the present disclosure. [Figure 11] FIG. 10 is a diagram conceptually illustrating mapping data according to a modification of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] A display device according to an embodiment of the present disclosure will be described with reference to the drawings. 1, the display device 1 is mounted in a dashboard 205 of a vehicle 200. The display device 1 projects display light L onto a windshield 201, which is a projection receiving member, to display a projection image including vehicle information such as vehicle speed, so that the projection image can be viewed by a viewer U. In other words, the display device 1 is a projection-type display device, and in particular, a windshield display (WSD) in which the display light L from a display panel 5 (described later) of the display device 1 is directly projected onto the windshield 201.

[0010] The windshield 201 has a light-transmitting portion 202 and a light-blocking portion 203. The light-transmitting portion 202 is a portion that allows a viewer U inside the vehicle cabin to view the actual scenery outside the vehicle cabin. The light-blocking portion 203 is located at the lower end of the light-transmitting portion 202 and is formed in an area of ​​the windshield 201 on the dashboard 205 side. The light-blocking portion 203 is formed of a black ceramic print. The display device 1 is configured to be able to project the display light L onto a range spanning the light-blocking portion 203 and the dashboard 205, but as will be described later, an unused area is set in part of the display panel 5, so that the display light L is not projected onto the dashboard 205 under control and the display light L is projected only onto the light-blocking portion 203.

[0011] As shown in FIG. 2, the display device 1 includes a control unit 2, a backlight unit 4, and a display panel 5.

[0012] As shown in Fig. 3, the display panel 5 is a TFT (Thin Film Transistor) type liquid crystal panel, and displays an image B by receiving illumination light from the backlight unit 4. The display panel 5 has a display surface 51 that displays the image B including vehicle information. The display surface 51 is formed on the front surface of the display panel 5, and has a rectangular shape that is long in the vehicle width direction.

[0013] The backlight unit 4 irradiates the back side of the display panel 5 (the side opposite to the display surface 51) with illumination light. The backlight unit 4 includes a plurality of drivers 4d and a plurality of light sources L1 to Ln (n is an arbitrary natural number). 7, the multiple light sources L1 to Ln are each composed of an LED (Light Emitting Diode), and are arranged in a matrix in two mutually orthogonal directions (H direction and V direction in FIGS. 3 to 7) along the display surface 51. The H direction is the horizontal direction that is the width direction of the vehicle, and the V direction is the vertical direction that is along the height direction.

[0014] The driver 4d is a constant current LED driver with a PWM (Pulse Width Modulation) dimming function. 2, each driver 4d receives a dimming command signal J from the control unit 2 and outputs drive signals P1 to Pn, which are PWM signals, to the corresponding light sources L1 to Ln, thereby driving the light sources L1 to Ln to light up at the required brightness. Each driver 4d is configured to be able to drive the light sources L1 to Ln for the number of channels. The number of channels of the driver 4d may be 16, 24, 48, or 96, for example.

[0015] The control unit 2 controls the display panel 5 and the backlight unit 4. The control unit 2 includes a processing unit 2a such as a CPU (Central Processing Unit) and a GDC (Graphics Display Controller), and a storage unit 2b such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The processing unit 2a receives image data F and vehicle information such as vehicle speed from the outside, and simultaneously executes image control to display an image B on the display surface 51 and backlight control to turn on the backlight unit 4. The processing unit 2a generates an image B by setting brightness and color using RGB values ​​for each pixel on the display surface 51. As shown in Fig. 4, the image B includes a vehicle speed B1 and icons B2 and B3 as display contents on a black background.

[0016] As shown in Fig. 5, the processing unit 2a performs local dimming control to control the brightness of each of a plurality of regions Ar into which the display surface 51 is partitioned. In this embodiment, the display surface 51 is divided into six regions in the H direction (horizontal direction) and three regions in the V direction (vertical direction), thereby setting a total of 18 regions Ar. Each region Ar is set to have the same area. The positions of the regions Ar are represented by (1,1) to (3,6). For example, the third region Ar from the top and the first region Ar from the left is represented by region Ar(3,1). In this embodiment, one light source L1 to Ln is provided at the center of each area Ar. That is, there is a one-to-one correspondence between the areas Ar and the light sources. The processing unit 2a controls the light emission of the light sources L1 to Ln via a driver 4d, thereby controlling the brightness of each of the multiple areas Ar.

[0017] Next, the local dimming control process executed by the processing unit 2a will be described with reference to the flowchart of Fig. 8. This local dimming control process is executed by the processing unit 2a in accordance with an operation program stored in the storage unit 2b, and is repeatedly executed while the image B is being displayed. Upon receiving the image data F, the processing unit 2a determines the brightness required for each area Ar according to the image data F (step S101). As shown in FIG. 5, this required brightness is set as a dimming rate between 0 and 100%. In the example of FIG. 5, the numerical value displayed in the center of the area Ar is the dimming rate of that area Ar. In an area Ar where the dimming rate is 0%, the light source corresponding to that area Ar is turned off. In an area Ar where the dimming rate is 100%, the light source corresponding to that area Ar is turned on at maximum brightness. The required brightness (dimming rate) for each area Ar is a value according to the display content of image B, as shown in FIG. 4. The required brightness (dimming rate) of the area Ar including display content (vehicle speed B1 and icons B1 and B2) is set higher than the required brightness (dimming rate) of the area Ar not including display content. In the areas Ar(1,5), (2,1), (2,6), (3,1) to (3,6) not including display content, a black image is displayed throughout the entire area. The areas Ar(3,1) to (3,6) below the display surface 51 (image B) correspond to the areas of the display light L that are projected onto the dashboard 205 (see FIG. 1). The areas Ar(3,1) to (3,6) are unused areas where no content is displayed, regardless of the content of image B.

[0018] Next, the processing unit 2a generates mapping data N by skipping information on the area Ar where the dimming rate is 0% from the required brightness for each area Ar, and stores the data in the storage unit 2b (step S102).Then, the processing unit 2a generates a dimming command signal J from the stored mapping data N, and outputs the generated dimming command signal J to each driver 4d (step S103), thereby completing the local dimming control process. As shown in Fig. 6, the generated mapping data N is data that omits information about the area Ar where the dimming rate is 0% from the data showing the dimming rate of each area Ar shown in Fig. 5. In other words, the mapping data N is made up of data that associates the position of the area Ar where the dimming rate is not 0% with the dimming rate of that area Ar.

[0019] The dimming command signal J is a signal in which information indicating the required brightness (dimming rate) of the region Ar where the dimming rate is not 0% is arranged in a predetermined order. A dimming command signal according to a comparative example in which information of the region Ar where the dimming rate is 0% is not omitted is a signal in which information indicating the dimming rates of all regions is arranged in the order of the region Ar (1,1) → (1,2) → (1,3) → (1,4) → (1,5) → (1,6) → (2,1) → (2,2) → (2,3) → (2,4) → (2,5) → (2,6) → (3,1) → (3,2) → (3,3) → (3,4) → (3,5) → (3,6). The dimming command signal J according to this embodiment is generated from mapping data N that omits information about the 0% dimming ratio region Ar. Therefore, in this embodiment, the dimming command signal J does not include information about the 0% dimming ratio region Ar. Specifically, in the example of FIG. 5 , the dimming command signal J in the comparative example is [90, 60, 60, 40, 0, 90, 0, 80, 80, 70, 40, 0, 0, 0, 0, 0, 0]. However, in this embodiment, the "0"s are omitted, resulting in [90, 60, 60, 40, 90, 80, 80, 70, 40]. In this example, the data amount of the dimming command signal J can be reduced by 50% compared to the comparative example.

[0020] (effect) According to the embodiment described above, the following effects are achieved. (1) The display device 1 includes a liquid crystal display panel 5 having a display surface 51 for displaying an image B, a plurality of light sources L1-Ln arranged along the display surface 51 to illuminate the display panel 5, a driver 4d for driving the plurality of light sources L1-Ln, and a control unit 2 that controls the light emission of the plurality of light sources L1-Ln by outputting a dimming command signal J to the driver 4d, and performs local dimming control to adjust the brightness for each of a plurality of regions Ar into which the display surface 51 is partitioned by this light emission control. The dimming command signal J has information related to the brightness of each of the plurality of regions Ar arranged in order, includes information related to the regions Ar where the brightness is greater than zero, and omits information related to the regions Ar where the brightness is zero. According to this configuration, since information regarding the area Ar where the luminance is zero is omitted from the dimming command signal J, the amount of data related to the dimming command signal J relating to the lighting control of the light sources L1 to Ln can be reduced.

[0021] (2) A light source is provided for each of the multiple regions Ar. According to this configuration, the luminance of any area Ar can be made greater than zero depending on the content of image B, making it possible to accommodate a variety of image displays.

[0022] (3) The control unit 2 calculates the luminance required for each of the multiple regions Ar, stores the calculated luminance for each region Ar as mapping data N, and generates and outputs a dimming command signal J to the driver 4d based on the stored mapping data N. The mapping data N is stored in such a way that the regions Ar where the luminance is zero are omitted. According to this configuration, the amount of data related to the dimming command signal J generated from the mapping data N can be reduced.

[0023] The present disclosure is not limited to the above-described embodiments and drawings. Modifications (including deletion of components) may be made as appropriate within the scope of the present disclosure. An example of such a modification is described below.

[0024] (Variation) In the above embodiment, processing unit 2a generates mapping data N that skips and omits information about region Ar where the dimming rate is 0%, but it is also possible to use mapping data N that is pre-stored in storage unit 2b instead of generating this mapping data N. This pre-stored mapping data N omits information about region Ar where the dimming rate is always 0% (e.g., regions Ar(3,1) to (3,6)), regardless of the content of image B, and does not need to omit information about region Ar where the dimming rate may be greater than 0% depending on the content of image B. In this modified example, the process of determining the required brightness for each region Ar according to image data F (step S101) can be omitted.

[0025] In the above embodiment, the processing unit 2a may perform warping processing to distort the image B to cancel out distortion in the projected image (virtual image), as shown in Fig. 10. In this case, the processing unit 2a changes the mapping data N (see Fig. 11) and the dimming command signal J to match the image B (see Fig. 10) after the warping processing. For example, in the example of Fig. 11, the regions Ar(3,1) to (3,4) and (3,6) are omitted from the mapping data N to match the image B after the warping processing, and the dimming command signal J becomes [40, 50, 60, 40, 10, 20, 80, 80, 80, 70, 40, 90, 10].

[0026] In the above embodiment, the display device 1 projects the display light L onto the light-shielding portion 203 of the windshield 201, but this is not limiting, and the display light L may be projected onto the light-transmitting portion 202 of the windshield 201. In this case, the projected image may be superimposed on the actual scenery. The display device 1 may also include one or more mirrors that reflect the display light L from the display panel 5 and guide it to the windshield 201. In the above embodiment, the light blocking portion 203 of the windshield 201 may be omitted. In the above embodiment, the display device 1 may project the display light L onto a dedicated combiner. Furthermore, the display device 1 is not limited to a projection type display device, but may also be a direct-view type display device. Furthermore, the display device 1 may be mounted on something other than a vehicle, or may be configured to be usable independently without being mounted on another object. The number of drivers 4d can be changed as needed.

[0027] In the above embodiment, the area Ar(3,1) to (3,6) at the bottom of image B was the unused area, but the unused area is not limited to the bottom of image B, and may be set at the top of image B, the right side of image B, the left side of image B, or the outer frame of image B.

[0028] In the above embodiment, one light source is associated with one area Ar, but this is not limiting, and a plurality of light sources may be associated with one area Ar.

[0029] In the above embodiment, the numbers of light sources L1 to Ln, drivers 4d, and areas Ar can be changed as appropriate. For example, the number of light sources L1 to Ln may be 429 [pcs], the number of channels of the driver 4d may be 16 [ch], the number of drivers 4d may be 27 [pcs], and the number of areas Ar may be 429 [Zones].

[0030] In the above embodiment, the multiple light sources L1 to Ln are arranged in a matrix in the H and V directions, but this is not limiting. Of the multiple light sources L1 to Ln, light sources corresponding to the area Ar where the dimming rate is always 0% regardless of the content of the image B may be omitted. For example, light sources L13 to L21 corresponding to the area Ar(3,1) to (3,6) that overlaps with the dashboard 205 may be omitted. In this case, as shown in FIG. 9, only light sources L1 to L12 corresponding to the areas Ar(1,1) to (2,6) are arranged. This modification provides the following advantages. One light source is provided for each of the multiple regions Ar whose luminance is greater than zero. No light source or driver is provided for each of the multiple regions Ar whose luminance is zero. This configuration eliminates the need for a light source and a driver corresponding to each area Ar in image B where the luminance is always zero, thereby simplifying the configuration of the display device 1. Furthermore, the display device 1 can be configured inexpensively. [Explanation of symbols]

[0031] 1...Display device 2...control unit, 2a...processing unit, 2b...storage unit 4...Backlight unit, 4d...Driver, L1-Ln...Light source 5...display panel, 51...display surface 200...vehicle, 201...windshield, 202...transparent portion, 203...light-shielding portion, 205...dashboard B...Image, B1...Vehicle speed, B2, B3...Icon F...image data, J...dimming command signal, N...mapping data, P1-Pn...drive signal, Ar...area, L...display light, U...viewer

Claims

1. a liquid crystal display panel having a display surface for displaying an image; a plurality of light sources arranged along the display surface for illuminating the display panel; a driver that drives the plurality of light sources; a control unit that outputs a dimming command signal to the driver to control the light emission of the plurality of light sources, and performs local dimming control to adjust the brightness of each of the plurality of regions into which the display surface is partitioned by this light emission control; The dimming command signal includes information about the luminance of each of the plurality of regions arranged in order, includes information about the regions whose luminance is greater than zero, and omits information about the regions whose luminance is zero. Display device.

2. One or more light sources are associated with each of the plurality of regions. The display device according to claim 1 .

3. one or more light sources among the plurality of light sources are provided corresponding to regions among the plurality of regions whose luminance is greater than zero, No light source is provided corresponding to an area of ​​the plurality of areas where the luminance is zero. The display device according to claim 1 .

4. the control unit calculates a luminance required for each of the plurality of regions, stores the calculated luminance for each of the regions as mapping data, generates the dimming command signal based on the stored mapping data, and outputs the dimming command signal to the driver; The mapping data is stored in a state in which areas of the plurality of areas where the luminance is zero are omitted. The display device according to claim 1 .

Images