Display device

Abstract

In a display device (1), a display panel (12) displays a first image (P1) in a first image region (A1) in a display region (D1). The backlight (14) is located on the rear surface of the display panel (12) and emits light to the display panel (12). The illuminance sensor (22) detects the illuminance of incident light. The control circuit (20) controls the backlight (14) in accordance with the illuminance. The backlight (14) has a plurality of light sources (16) arranged in a matrix. When the illuminance is less than a first threshold value, which is a predetermined value, the control circuit (20) turns on a first light source group comprising at least one light source (16) among the plurality of light sources (16) that overlaps the first image region (A1) when viewed from the normal direction of the display panel (12). When the illuminance is equal to or greater than a first threshold value, the control circuit (20) lights at least one light source (16) among a first light source group and a first outer peripheral light source group comprising light sources (16) located on the outer periphery of the first light source group among the plurality of light sources (16).

Description

Technical Field

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

[0002] There is known an image display device that controls the brightness of an LED backlight according to ambient illumination (see, for example, Patent Document 1).

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-37015 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] Further improvements are sought in display devices.

[0008] [Technical solutions for solving technical problems]

[0009] In order to solve the above-mentioned problem, a display device of a scheme of the present disclosure includes: a display panel that displays a first image in a first image area in a display area; a backlight that is located on the back of the display panel and irradiates light to the display panel; an illuminance sensor that detects the illuminance of the incident light; and a control circuit that controls the backlight according to the illuminance. The backlight has a plurality of light sources arranged in a matrix. When the illuminance is less than a first threshold value that is a predetermined value, the control circuit turns on a first light source group consisting of at least one light source overlapping with the first image area when viewed from the normal direction of the display panel among the plurality of light sources, and when the illuminance is greater than the first threshold value, the control circuit turns on at least one light source in the first light source group and a first peripheral light source group consisting of light sources located on the periphery of the first light source group among the plurality of light sources.

[0010] [Effects of the invention]

[0011] Through the above solution, further improvement can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing the configuration of a display device according to the first embodiment.

[0013] Figure 2 Yes means Figure 1 A diagram showing the relationship between the illuminance of incident light in a display device and the brightness of the first image area.

[0014] Figure 3 This indicates that the incident light intensity is less than the first threshold value. Figure 1 A diagram showing the lighting status of the backlight.

[0015] Figure 4 This indicates that the incident light intensity is greater than the first threshold and less than the second threshold. Figure 1 A diagram showing the lighting status of the backlight.

[0016] Figure 5 This indicates that the incident light intensity is greater than the second threshold and less than the third threshold. Figure 1 A diagram showing the lighting status of the backlight.

[0017] Figure 6 This is a diagram showing the lighting state of the backlight when the illuminance of incident light is equal to or greater than the third threshold value.

[0018] Figure 7 It is a diagram showing the relationship between the illuminance of incident light and the brightness of the first image area in the display device according to the second embodiment.

[0019] Figure 8 This is a diagram showing the lighting state of the backlight when the illuminance of incident light is less than the first threshold value according to the second embodiment, superimposed on a plurality of images.

[0020] Fig. 9 This is a diagram showing the lighting state of the backlight when the illuminance of incident light according to the second embodiment is equal to or greater than a first threshold value and less than a second threshold value, in a superimposed manner on a plurality of images.

[0021] Fig.10 This is a diagram showing the lighting state of the backlight when the illuminance of incident light is equal to or greater than the second threshold value according to the second embodiment, superimposed on a plurality of images.

[0022] Fig.11 This is a diagram showing the lighting state of the backlight when the illuminance of incident light is less than the first threshold value according to the third embodiment, superimposed on a plurality of images.

[0023] Fig.12 This is a diagram showing the lighting state of the backlight when the illuminance of incident light according to the third embodiment is equal to or greater than a first threshold value and less than a second threshold value, in a superimposed manner on a plurality of images.

[0024] Fig.13 This is a diagram showing the lighting state of the backlight when the illuminance of incident light according to the modification of the third embodiment is equal to or greater than a first threshold value and less than a second threshold value, in a superimposed manner on a plurality of images.

[0025] Fig.14 This is a diagram showing the lighting state of the backlight when the illuminance of incident light is less than the first threshold value according to the fourth embodiment, superimposed on a plurality of images.

[0026] Fig.15This is a diagram showing the lighting state of the backlight when the illuminance of incident light according to the fourth embodiment is equal to or greater than a first threshold value and less than a second threshold value, in a superimposed manner on a plurality of images.

[0027] Fig.16 It is used to determine Figure 1 Flowchart of an example of a control process of a control circuit. DETAILED DESCRIPTION

[0028] (Knowledge that forms the basis of this disclosure)

[0029] Before describing the implementation method in detail, the basic understanding is described. In a display device including a display panel for displaying an image and a backlight having a plurality of light sources for irradiating light to the display panel, when the illumination of external light is high, the image is displayed brightly by increasing the brightness of the light source overlapping the image, thereby improving the visibility of the image.

[0030] However, the present inventors have found that there is a limit to the increase in the brightness of an image caused by increasing the brightness of a light source superimposed on an image. In order to solve this problem, the display device of the present disclosure is configured as follows.

[0031] Hereinafter, the same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, for easy understanding, the sizes of the members in the drawings are appropriately enlarged or reduced.

[0032] (First embodiment)

[0033] Figure 1 The configuration of the display device 1 according to the first embodiment is shown. The display device 1 is described as an example of a vehicle-mounted display device, but the use of the display device 1 is not particularly limited. The display device 1 may be, for example, a display device of a portable electronic device or a display device of a fixed electronic device.

[0034] The display device 1 is, for example, disposed near the center of a central console in a vehicle compartment. The display device 1 displays various information. External light such as sunlight is incident on the display surface of the display device 1 from the window of the vehicle, and the external light is positively reflected on the display surface, sometimes directed toward the driver's eyes. In this case, it may be difficult for the driver to recognize the display content of the display device 1. Therefore, the display device 1 detects the illuminance near the display surface, and the greater the detected illuminance, the greater the screen brightness. Thus, the visibility of the display device 1 can be improved when the illuminance of the incident light is large.

[0035] The display device 1 includes a display unit 10 , a control circuit 20 , and an illuminance sensor 22 . The display unit 10 includes a display panel 12 and a backlight 14 .

[0036] The display panel 12 is a liquid crystal panel. The display panel 12 displays at least one image in the display area D1. In the example shown in the figure, the display panel 12 displays the first image P1 as a graphic representing the text "A" in the first image area A1 which is a part of the display area D1, and does not display any other images. The first image area A1 is, for example, a rectangle. In the case where the first image P1 is a single graphic as in the example shown in the figure, the first image area A1 may be an area having substantially the same shape as the first image P1. In the case where the first image P1 is a collection of multiple images, the first image area A1 may also be an area surrounding the multiple images. In the case where the first image P1 is more than one text, the first image area A1 may also be an area surrounding more than one text.

[0037] The backlight 14 is a direct-down type backlight. The backlight 14 is located on the back side of the display panel 12 and irradiates light to the display panel 12. The backlight 14 includes a plurality of light sources 16 for illuminating the display panel 12. Light-emitting diodes (LEDs) not shown in the figure are respectively arranged in the plurality of light sources 16. The plurality of light sources 16 are arranged in a matrix shape, for example. Each light source 16 constitutes a light-emitting area. The plurality of light sources 16 do not necessarily need to be arranged regularly, and may also be arranged irregularly according to the shape of the display panel 12 or the display content. The brightness of each light source 16 can be controlled individually.

[0038] The control circuit 20 displays an image on the display panel 12 via a liquid crystal drive circuit (not shown). The control circuit 20 controls the backlight 14 via a light source drive circuit (not shown), and controls the brightness of each light source 16. The control circuit 20 changes the brightness of each light source 16 according to the image displayed on the display panel 12. This control is called local dimming. As a result, power consumption can be reduced and the contrast of the image can be improved.

[0039] The illuminance sensor 22 detects the illuminance of the incident light to the display device 1, and outputs a signal indicating the detected illuminance to the control circuit 20. The illuminance sensor 22 is arranged next to the display panel 12 when viewed from the observer's side. Thus, it is possible to detect an illuminance close to the illuminance of the external light incident on the display panel 12. The control circuit 20 controls the backlight 14 based on the illuminance detected by the illuminance sensor 22.

[0040] Figure 2 express Figure 1 The relationship between the illuminance of the incident light in the display device 1 and the brightness of the first image area A1. Figure 2, as thresholds related to illuminance, a first threshold Th1, a second threshold Th2, and a third threshold Th3, which are predetermined values, are shown. These thresholds can be appropriately determined through experiments or simulations.

[0041] Figure 3 Indicates the lighting state of the backlight 14 when the illuminance of the incident light is less than the first threshold value Th1. Figure 3 The figures are when the display panel 12 is viewed from the normal direction on the observer side.

[0042] When the illuminance is less than the first threshold value Th1, the control circuit 20 turns on the first light source group G1 composed of at least one light source 16 that overlaps the first image area A1 when viewed from the normal direction of the display panel 12, among the plurality of light sources 16. That is, at least a portion of each light source 16 constituting the first light source group G1 overlaps the first image area A1. Here, it is assumed that the entirety of one light source 16 overlaps the first image area A1, and the other plurality of light sources 16 do not overlap the first image area A1.

[0043] As in the example described later, depending on the size of the first image P1, that is, the size of the first image area A1, there may be a case where a plurality of light sources 16 overlap with the first image area A1. In this case, the first light source group G1 is composed of a plurality of light sources 16 overlapping with the first image area A1. The so-called "light source group" refers to one or more light sources 16.

[0044] When the illuminance is less than the first threshold value Th1, the control circuit 20 lights up the first light source group G1 at a brightness that is higher as the illuminance increases and is less than a predetermined brightness. The predetermined brightness is the maximum brightness that can be set in one light source 16, for example, the brightness when a rated current flows. Hereinafter, lighting up the light source 16 at a brightness less than the predetermined brightness is sometimes referred to as dimming lighting. The control circuit 20 dims and lights up the first light source group G1 according to the illuminance. The control circuit 20 turns off the light sources 16 other than the first light source group G1.

[0045] In the diagram showing the lighting state of the backlight 14, black indicates an off state, and the closer to white the black is, the higher the brightness becomes. In the diagram showing the lighting state of the backlight 14, an example in which the number of light sources 16 is "32" is shown, but the number of light sources 16 is not limited to "32".

[0046] Figure 4 The lighting state of the backlight 14 is shown when the illuminance of the incident light is greater than or equal to the first threshold value Th1 and less than the second threshold value Th2. Figures 4 to 6 In the figure, the illustration of the first image area A1 is omitted.

[0047] When the illuminance is greater than or equal to the first threshold value Th1 and less than the second threshold value Th2, the control circuit 20 turns on the first light source group G1 and the first group Ga1 which is part of the first peripheral light source group OG1 surrounding the first light source group G1. The first peripheral light source group OG1 is composed of eight light sources 16 located on the periphery of the first light source group G1.

[0048] exist Figure 4 In the example of , the first group Ga1 is composed of two light sources 16 adjacent to the light source 16 of the first light source group G1, and two light sources 16 adjacent to the first light source group G1. Which light source 16 in the first peripheral light source group OG1 is used as the first group Ga1 can be appropriately determined. The first group Ga1 is also composed of one or more light sources 16.

[0049] The control circuit 20 lights up the first light source group G1 at a predetermined brightness when the illuminance is equal to or higher than the first threshold Th1 , and lights up the first light source group Ga1 at a higher brightness as the illuminance increases.

[0050] Figure 5 Indicates the case where the illuminance of the incident light is greater than or equal to the second threshold value Th2 and less than the third threshold value Th3 Figure 1 The lighting state of the backlight 14.

[0051] When the illuminance is equal to or higher than the second threshold Th2, the control circuit 20 turns on the first light source group G1, the first light source group Ga1, and the second light source group Gb1 which is a part of the first peripheral light source group OG1 and is different from the first light source group Ga1.

[0052] exist Figure 5 In the example of , the second group Gb1 is composed of four light sources 16 that are obliquely adjacent to the light source 16 of the first light source group G1. That is, all of the first peripheral light source group OG1 will be lit. Which light source 16 in the first peripheral light source group OG1 is used as the second group Gb1 can be appropriately determined. The second group Gb1 is also composed of one or more light sources 16. When the illuminance is greater than the second threshold value Th2, only a part of the first peripheral light source group OG1 may be lit.

[0053] When the illuminance is equal to or greater than the second threshold value Th2, the control circuit 20 lights up the first group Ga1 and the second group Gb1 at a higher brightness as the illuminance increases. Figure 5 In the example, the brightness of the first group Ga1 and the second group Gb1 are equal, and the brightness of the first group Ga1 and the second group Gb1 are also equal when the illumination is equal to the second threshold Th2. However, the brightness of the first group Ga1 and the second group Gb1 may be different, and can be appropriately determined so that the relationship between the illumination of the incident light and the brightness of the first image area A1 becomes a desired relationship.

[0054] Figure 6 The lighting state of the backlight 14 is shown when the illuminance of incident light is equal to or greater than the third threshold Th3. When the illuminance is equal to or greater than the third threshold Th3, the control circuit 20 lights the first light source group G1, the first light source group Ga1, and the second light source group Gb1 at predetermined brightness.

[0055] Thus, when the illuminance is greater than the first threshold value Th1, the control circuit 20 turns on at least one of the first light source group G1 and the first peripheral light source group OG1 among the plurality of light sources 16. When the illuminance is greater than the first threshold value Th1, the control circuit 20 turns on at least one of the first peripheral light source group OG1 with a brightness that increases as the illuminance increases.

[0056] When the display panel 12 displays a plurality of images, the control circuit 20 executes the above control for each image.

[0057] As described above, when the illuminance is greater than or equal to the first threshold value Th1, in addition to the first light source group G1 overlapping the first image area A1, the light sources 16 surrounding the first light source group G1 are also turned on, so that the brightness of the first image area A1 can be increased compared to the case where only the first light source group G1 is turned on. Therefore, even when relatively strong external light such as sunlight enters the display area D1, deterioration in the visibility of the image can be suppressed.

[0058] In addition, when the illuminance is less than the first threshold value Th1, the first light source group G1 is dimmed and lit according to the illuminance; when the illuminance is greater than the first threshold value Th1, the first group Ga1 is dimmed and lit according to the illuminance; when the illuminance is greater than the second threshold value Th2, the first group Ga1 and the second group Gb1 are dimmed and lit according to the illuminance, thereby enabling the brightness of the first image area A1 to change smoothly according to the illuminance.

[0059] In addition, in the above example, three thresholds are used as thresholds related to illumination, but the threshold is not limited to three, and may be one, two, or more than four. The number of thresholds can be appropriately determined so that the relationship between the illumination of the incident light and the brightness of the first image area A1 becomes a desired relationship.

[0060] For example, when one first threshold value Th1 is used, the control circuit 20 may light up the first light source group G1 at maximum brightness when the illuminance is less than the first threshold value Th1, and may light up the first light source group G1 and at least one light source 16 in the first peripheral light source group OG1 at maximum brightness when the illuminance is greater than the first threshold value Th1. In this case, control can be simplified.

[0061] Furthermore, when two first threshold values ​​Th1 and second threshold values ​​Th2 are used, the control circuit 20 may dim and light up the first light source group G1 according to the illuminance when the illuminance is less than the first threshold value Th1. Alternatively, when the illuminance is greater than the first threshold value Th1 and less than the second threshold value Th2, the control circuit 20 may dim and light up the first light source group G1 and at least one light source 16 in the first peripheral light source group OG1 according to the illuminance. Alternatively, when the illuminance is greater than the second threshold value Th2, the control circuit 20 may light up the first light source group G1 and at least one light source 16 in the first peripheral light source group OG1 at maximum brightness. In this case, control can also be simplified.

[0062] (Second embodiment)

[0063] In the second embodiment, when the illuminance is greater than or equal to the first threshold Th1 and there are two adjacent image regions, the light source 16 overlapping the region between the two adjacent image regions is turned on, which is different from the first embodiment. The following description will focus on the differences from the first embodiment.

[0064] Figure 7 The relationship between the illuminance of incident light and the brightness of the first image area A1 in the display device 1 according to the second embodiment is shown. Here, a first threshold value Th1 and a second threshold value Th2 are used as threshold values ​​related to illuminance.

[0065] Figure 8 The lighting state of the backlight 14 when the illuminance of incident light in the second embodiment is less than the first threshold value Th1 is shown superimposed on a plurality of images. Figure 8 , described later Fig. 9 and Fig.10 , an example in which the number of the light sources 16 is “96” is shown, but the number of the light sources 16 is not limited to “96”.

[0066] The display panel 12 displays the first image P1 in the first image area A1 , the second image P2 in the second image area A2 , the third image P3 in the third image area A3 , the fourth image P4 in the fourth image area A4 , and the fifth image P5 in the fifth image area A5 .

[0067] The first image P1 includes a graphic showing the text "A" and the text "A" shown under the graphic. The second image P2 includes a graphic showing the text "B" and the text "B" shown under the graphic. The third image P3 includes a graphic showing the text "C" and the text "C" shown under the graphic. The fourth image P4 includes a graphic showing the text "D" and the text "D" shown under the graphic. The fifth image P5 includes a graphic showing the text "E" and the text "E" shown under the graphic. The first image P1 to the fifth image P5 are, for example, icons.

[0068] Let n be the number of images in the display area D1, and let i be an integer from 1 to n. When the illuminance is less than the first threshold value Th1, the control circuit 20 lights up the i-th light source group Gi, which is composed of at least one light source 16 overlapping the i-th image area Ai when viewed from the normal direction of the display panel 12, among the plurality of light sources 16, with a brightness that increases as the illuminance increases.

[0069] For example, regarding the first image P1, the eight light sources 16 of the first light source group G1 overlapping the first image area A1 are dimmed and lit according to the illuminance. Regarding the second image P2, the eight light sources 16 of the second light source group G2 overlapping the second image area A2 are dimmed and lit according to the illuminance.

[0070] Fig. 9 The lighting state of the backlight 14 when the illuminance of incident light in the second embodiment is greater than or equal to the first threshold value Th1 and less than the second threshold value Th2 is shown superimposed on a plurality of images. Fig. 9 In the display, the image area is omitted.

[0071] When the illuminance is greater than or equal to the first threshold value Th1, the control circuit 20 lights up at least one light source 16 in the i-th light source group Gi and the i-th peripheral light source group OGi consisting of the light sources 16 located on the periphery of the i-th light source group Gi, among the plurality of light sources 16, with a brightness that increases as the illuminance increases. The at least one light source 16 in the i-th peripheral light source group OGi that is lit up in this case is referred to as a first sub-light source group GAi.

[0072] Let j be an integer from 1 to n different from i. The control circuit 20 determines the light source 16 included in the i-th peripheral light source group OGi and the j-th peripheral light source group OGj to be lit when the illuminance is greater than or equal to the first threshold value Th1, based on the positional relationship between the i-th image Pi and the j-th image Pj.

[0073] Specifically, when the i-th image Pi is located near the j-th image Pj, the control circuit 20 determines to light up the first sub-light source group GAi in the i-th peripheral light source group OGi, which is composed of the light sources 16 located between the i-th light source group Gi and the j-th light source group Gj. When the light sources 16 of one row or one column are located between the i-th light source group Gi and the j-th light source group Gj, it is defined that the i-th image Pi is located near the j-th image Pj. When the i-th light source group Gi and the j-th light source group Gj are each composed of one light source 16, when one light source 16 is located between the i-th light source group Gi and the j-th light source group Gj, it is defined that the i-th image Pi is located near the j-th image Pj. The i-th image Pi being located near the j-th image Pj is also referred to as the i-th image Pi being close to the j-th image Pj.

[0074] For example, because the first image P1 is located near the second image P2, the first sub-light source group GA1 including four light sources 16 in one row located between the first light source group G1 and the second light source group G2 is dimmed and turned on.

[0075] That is, for example, when the first image P1 is located near the left side of the second image P2 , the control circuit 20 determines to light the light source 16 located on the right side of the first light source group G1 in the first peripheral light source group OG1 .

[0076] With this configuration, the first sub-light source group GA1 that is turned on illuminates both the first image area A1 and the second image area A2, so the brightness of these image areas can be effectively improved by using the light emitted from the first sub-light source group GA1. For example, assuming that the light source 16 located on the left side of the first light source group G1 in the first peripheral light source group OG1 is turned on, the light of the light source 16 actually only contributes to the brightness of the first image area A1. Therefore, it is efficient to turn on the first sub-light source group GA1. Therefore, the brightness of two adjacent image areas can be improved, and the increase in power consumption can be suppressed.

[0077] Fig.10 The lighting state of the backlight 14 when the illuminance of incident light in the second embodiment is equal to or greater than the second threshold value Th2 is shown superimposed on a plurality of images.

[0078] When the illuminance is greater than or equal to the second threshold value Th2, the control circuit 20 lights up the i-th light source group Gi and the i-th peripheral light source group OGi among the plurality of light sources 16 at maximum brightness. In the example shown in the figure, all the light sources 16 are lit. Since the plurality of outermost peripheral light sources 16 are also lit, the brightness near the edge of the image separated from the first sub-light source group GAi, such as the left edge of the first image P1, is also increased.

[0079] Alternatively, when the illuminance is equal to or greater than the second threshold value Th2, the control circuit 20 may light the i-th light source group Gi and the first sub-light source group GAi of the plurality of light sources 16 at maximum brightness and not light the other light sources 16. Fig. 9 Similarly, the outermost plurality of light sources 16 may not be turned on. In this case, although the brightness near the edge of the image is Fig.10 It will be somewhat lower than the case of , but it can reduce power consumption.

[0080] (Third embodiment)

[0081] In the third embodiment, when the illuminance is equal to or greater than the first threshold value Th1, the light source 16 to be additionally turned on is determined according to the importance of the image, unlike the first embodiment. The following description will focus on the differences from the first embodiment.

[0082] Fig.11 The lighting state of the backlight 14 when the illuminance of the incident light in the third embodiment is less than the first threshold value Th1 is shown superimposed on a plurality of images. An example in which the display panel 12 is a liquid crystal meter of a vehicle is shown. Fig.11 , described later Fig.12 and Fig.13 , an example in which the number of light sources 16 is “119” is shown, but the number of light sources 16 is not limited to “119”.

[0083] The display panel 12 displays the first image P1 in the first image area A1, the second image P2 in the second image area A2, the third image P3 in the third image area A3, the fourth image P4 in the fourth image area A4, the fifth image P5 in the fifth image area A5, the sixth image P6 in the sixth image area A6, the seventh image P7 in the seventh image area A7, the eighth image P8 in the eighth image area A8, and the ninth image P9 in the ninth image area A9.

[0084] The first image P1 and the second image P2 represent the direction indicator lights. The third image P3 represents the shift indicator lights. The fourth image P4 and the fifth image P5 represent the speedometer. The sixth image P6 represents the light on indicator lights, which indicate the lighting of the headlights, etc. The seventh image P7 represents the brake warning light, which indicates that the side brake is in action. The eighth image P8 represents the seat belt warning light, which warns against non-wearing of the seat belt. The ninth image P9 represents the door warning light, which warns against the opening of the door. The brake warning light, the seat belt warning light and the door warning light are also called telltales.

[0085] For the multiple images, the first image P1 to the ninth image P9, importance is set respectively. Importance can be expressed as "high" or "low" or as a numerical value. When importance is expressed as "high" or "low", high importance is equivalent to importance being above the importance threshold, and low importance is equivalent to importance being below the importance threshold.

[0086] Here, the 6th image P6 of the light on indicator light, the 7th image P7 of the brake warning light, the 8th image P8 of the seat belt warning light, and the 9th image P9 of the door warning light have higher importance. The 1st image P1, the 2nd image P2, the 3rd image P3, the 4th image P4, and the 5th image P5 have lower importance. It is preferred that the importance of the indicator image is higher, but the importance of other images can be appropriately determined.

[0087] When the illuminance is less than the first threshold value Th1, the control circuit 20 lights up the i-th light source group Gi consisting of at least one light source 16 overlapping with the i-th image area Ai when observed from the normal direction of the display panel 12, with higher brightness as the illuminance increases, regardless of the importance of the i-th image Pi.

[0088] For example, in the first image P1, the four light sources 16 of the first light source group G1 are dimmed and lit according to the illuminance. In the eighth image P8, the one light source 16 of the eighth light source group G8 is dimmed and lit according to the illuminance.

[0089] Fig.12 The lighting state of the backlight 14 when the illuminance of the incident light in the third embodiment is greater than or equal to the first threshold value Th1 and less than the second threshold value Th2 is shown superimposed on a plurality of images. Fig.12 and Fig.13 In the figure, the illustration of the image area is omitted.

[0090] When the importance of the i-th image Pi is less than the importance threshold and the illuminance is greater than the first threshold, the control circuit 20 lights up the i-th light source group Gi and the first sub-light source group GAi as part of the i-th peripheral light source group OGi with a brightness that increases as the illuminance increases. For example, the first sub-light source group GAi is composed of a plurality of light sources 16 that are adjacent to the light source 16 of the i-th light source group Gi.

[0091] When the importance of the i-th image Pi is greater than the importance threshold and the illuminance is greater than the first threshold, the control circuit 20 lights up the i-th light source group Gi, the first sub-light source group GAi, and the second sub-light source group GBi which is a part of the i-th peripheral light source group OGi and is different from the first sub-light source group SGAi, with a brightness that increases as the illuminance increases. For example, the second sub-light source group GBi is composed of a plurality of light sources 16 that are adjacent to the light source 16 of the i-th light source group Gi in the vertical and diagonal directions.

[0092] For example, regarding the eighth image P8 having a high importance, the eighth light source group G8 and the eighth peripheral light source group OG8 are dimmed and lit according to the illuminance. On the other hand, for example, regarding the first image P1 having a low importance, the first light source group G1 and the first sub-light source group GA1 are dimmed and lit according to the illuminance.

[0093] According to this configuration, when the illuminance is greater than the first threshold value Th1, when the importance of the i-th image Pi is greater than the importance threshold value, the brightness of the i-th image region Ai can be increased compared to images whose importance is less than the importance threshold value. Therefore, even when the illuminance of the incident light is relatively large, the 6th image P6, the 7th image P7, the 8th image P8, and the 9th image P9, which have higher importance, can be easily recognized compared to images with lower importance. For images with lower importance, since the second sub-light source group GBi above and below and diagonally of the i-th light source group Gi is not lit, visibility can be improved and an increase in power consumption of the display device 1 can be suppressed.

[0094] In addition, in Fig.11 , Fig.12 In the case where the type, importance, size, and display position of an image are pre-set, as in the case of a liquid crystal meter of a display device, the light sources 16 that are lit when the illuminance is equal to or higher than the first threshold value Th1 may be pre-set, and the control circuit 20 may pre-hold information for determining those light sources 16. On the other hand, in the case where the type, importance, size, and display position of an image are not pre-determined but are determined based on an image signal supplied to the control circuit 20, the control circuit 20 may determine the importance of the image based on the information on the importance of the image contained in the image signal.

[0095] (Variation of the third embodiment)

[0096] When the illuminance is equal to or greater than the first threshold value Th1, the brightness of the additionally turned-on light source 16 may be determined according to the importance of the image. The following description will focus on the differences from the third embodiment.

[0097] Fig.13 The lighting state of the backlight 14 when the illuminance of incident light according to the modification of the third embodiment is equal to or greater than the first threshold Th1 and less than the second threshold Th2 is shown superimposed on a plurality of images.

[0098] When the importance of the i-th image Pi is less than the importance threshold and the illuminance is greater than the first threshold Th1, the control circuit 20 lights up the i-th light source group Gi at maximum brightness, and lights up at least one light source 16 in the i-th peripheral light source group OGi with a brightness that increases as the illuminance increases.

[0099] When the importance of the i-th image Pi is equal to or greater than the importance threshold and the illuminance is equal to or greater than the first threshold Th1, the control circuit 20 turns on at least one light source 16 in the i-th light source group Gi and the i-th peripheral light source group OGi at maximum brightness.

[0100] exist Fig.13 In the example of , the control circuit 20 lights the i-th light source group Gi and the i-th peripheral light source group OGi when the illuminance is equal to or greater than the first threshold value Th1, regardless of the importance of the i-th image Pi.

[0101] For example, regarding the 8th image P8 with a higher importance, the 8th light source group G8 and the 8th peripheral light source group OG8 are lit at maximum brightness. On the other hand, for example, regarding the 1st image P1 with a lower importance, the 1st light source group G1 is lit at maximum brightness, and the 1st peripheral light source group OG1 is dimmed and lit according to the illuminance.

[0102] According to this configuration, when the illumination is greater than or equal to the first threshold value Th1, when the importance of the i-th image Pi is greater than or equal to the importance threshold value, the brightness of the i-th image region Ai can be increased compared to the case where the importance is less than the importance threshold value. Therefore, even when the illumination of the incident light is relatively large, the sixth image P6, the seventh image P7, the eighth image P8, and the ninth image P9, which have high importance, can be easily recognized.

[0103] (Fourth embodiment)

[0104] In the fourth embodiment, when the illuminance is equal to or greater than the first threshold value Th1, the light source 16 to be additionally turned on is determined according to the size of the image, unlike the first embodiment. The following description will focus on the differences from the first embodiment.

[0105] Fig.14 The lighting state of the backlight 14 when the illuminance of incident light in the fourth embodiment is less than the first threshold value Th1 is shown superimposed on a plurality of images. Fig.14 and the following Fig.15 In FIG. 1 , an example is shown in which the number of light sources 16 is “96”, but the number of light sources 16 is not limited to “96”. Fig.14 In the example of , the display panel 12 displays the first image P1 to the seventh image P7.

[0106] The first image P1 is a graphic showing the text "A". The second image P2 is a graphic showing the text "B". The third image P3 is a graphic showing the text "C". The fourth image P4 is a graphic showing the text "D". The fifth image P5 is a graphic showing the text "E". The sixth image P6 is a graphic showing the text "F". The seventh image P7 is a graphic showing the text "G".

[0107] The size of each of the first image P1 to the fourth image P4 is greater than the size threshold. The size of each of the fifth image P5 to the seventh image P7 is less than the size threshold. The size of an image is equivalent to the size of the image area of ​​the image. The size of an image can be represented, for example, by the number of light sources 16 whose image areas overlap. For example, the size of the first image P1 is "4" and the size of the fifth image P5 is "1". In the present embodiment, the size threshold is, for example, "3".

[0108] When the illuminance is less than the first threshold value Th1, the control circuit 20 lights up the i-th light source group Gi consisting of at least one light source 16 that overlaps with the i-th image area Ai when observed from the normal direction of the display panel 12, with higher brightness as the illuminance increases, regardless of the size of the i-th image Pi.

[0109] For example, in the first image P1, the four light sources 16 of the first light source group G1 are dimmed and lit according to the illuminance. In the fifth image P5, the one light source 16 of the fifth light source group G5 is dimmed and lit according to the illuminance.

[0110] Fig.15 The lighting state of the backlight 14 when the illuminance of incident light in the fourth embodiment is greater than or equal to the first threshold Th1 and less than the second threshold Th2 is shown superimposed on a plurality of images. Fig.15 In the display, the image area is omitted.

[0111] When the size of the i-th image Pi is greater than the size threshold and the illuminance is greater than the first threshold Th1, the control circuit 20 lights up the i-th light source group Gi and the first sub-light source group GAi as part of the i-th peripheral light source group OGi with a brightness that increases as the illuminance increases. For example, the first sub-light source group GAi is composed of a plurality of light sources 16 that are adjacent to the light source 16 of the i-th light source group Gi.

[0112] When the size of the i-th image Pi is smaller than the size threshold and the illuminance is greater than or equal to the first threshold Th1, the control circuit 20 lights up the i-th light source group Gi, the first sub-light source group GAi, and the second sub-light source group GBi which is a part of the first peripheral light source group OGi and different from the first sub-light source group GAi, with a brightness that increases as the illuminance increases. For example, the second sub-light source group GBi is composed of a plurality of light sources 16 that are adjacent to the light source 16 of the i-th light source group Gi in the vertical and diagonal directions.

[0113] For example, regarding the first image P1 having a large size, the four light sources 16 of the first light source group G1 and the four light sources 16 of the first sub-light source group GA1 are dimmed and lit according to the illuminance. Since at least eight light sources 16 illuminate the first image P1, the brightness of the first image P1 can be increased.

[0114] On the other hand, for example, regarding the fifth image P5 having a smaller size, one light source 16 of the fifth light source group G5, two light sources 16 of the first sub-light source group GA5, and six light sources 16 of the second sub-light source group GB5 are dimmed and lit according to the illumination. Since nine light sources 16 illuminate the fifth image P5, the brightness of the fifth image P5 can be increased.

[0115] That is, the first image P1 having a larger size has more light sources 16 in the first light source group G1 and the first sub-light source group GA1 than the fifth image P5 having a smaller size, so that even if the number of light sources 16 to be additionally lit is smaller, the same brightness can be obtained.

[0116] According to this configuration, when the size of the i-th image Pi is greater than the size threshold, only the first sub-light source group GAi which is a part of the i-th peripheral light source group OGi is lit, thereby improving the brightness of the i-th image area Ai and suppressing an increase in power consumption of the display device 1.

[0117] The first to fourth embodiments have been described above, but it is also possible to display the image of the display object in accordance with the following: Fig.16 Whether to execute any one of the controls in the first to fourth embodiments is determined by referring to the flowchart of FIG.

[0118] Alternatively, when the importance, size, and display position of the image are predetermined, the designer of the display device 1 may determine the control according to the flowchart and design the control circuit 20 to execute the determined control. On the other hand, when the type, importance, size, and display position of the image are not predetermined and are determined based on the image signal supplied to the control circuit 20, the control circuit 20 may execute the processing of the following flowchart based on the image signal.

[0119] Fig.16 It is used for Figure 1 1 is a flowchart of an example of a process for controlling the control circuit 20 to perform a certain process. Hereinafter, an example of the process executed by the control circuit 20 will be described. This process is repeatedly executed.

[0120] The control circuit 20 obtains images based on the image signal (S10) and determines the importance of each image (S12). When it is determined that only images with a "low" importance are displayed, the control circuit 20 determines the size of each image (S14). When it is determined that only images smaller than a size threshold are displayed, the control circuit 20 determines whether the images are close (S16). When it is determined that the images are close ("Yes" in S16), the control circuit 20 determines to perform the control of the second embodiment (S18) and ends the processing. When it is determined in step S16 that the images are not close ("No" in S16), the control circuit 20 determines to perform the control of the first embodiment (S20) and ends the processing.

[0121] When it is determined in step S14 that images smaller than the size threshold and images larger than the size threshold are mixed, the control circuit 20 determines whether the images are close to each other (S22). When it is determined that the images are close to each other ("Yes" in S22), the control circuit 20 determines to perform the control of the fourth embodiment (S24) and ends the processing. When it is determined in step S22 that the images are not close to each other ("No" in S22), the control circuit 20 determines to perform the control of the first embodiment (S26) and ends the processing.

[0122] When it is determined in step S14 that only images larger than the size threshold are displayed, the control circuit 20 determines to perform standard control (S28) and terminates the processing. The so-called standard control means that the i-th light source group Gi composed of the light sources 16 overlapping the i-th image area Ai is dimmed and lit only according to the illumination. Here, for example, the size threshold is set to "9", and it is assumed that when the size of the image is larger than "3×3", the number of light sources 16 of the i-th light source group Gi is also larger than "3×3". Only by increasing the brightness of the light sources 16 of the i-th light source group Gi, the brightness of the i-th image area Ai is increased to the desired value.

[0123] When it is determined in S12 that images with a relatively low importance and images with a relatively high importance are mixed, the control circuit 20 determines to perform the control of the third embodiment or its modified example (S30) and ends the processing. In addition, in this case, it is also possible that when the images are close, the control circuit 20 combines the control of the second embodiment with the third embodiment or its modified example.

[0124] When it is determined in S12 that only images with a high importance are displayed, the control circuit 20 determines the size of each image (S32). When it is determined that images smaller than the size threshold are included, the control circuit 20 determines to perform the control of the first embodiment (S34) and ends the processing. When it is determined that only images larger than the size threshold are displayed, the control circuit 20 determines to perform the standard control (S36) and ends the processing.

[0125] The present disclosure has been described above based on the embodiments. It should be understood by those skilled in the art that the embodiments are merely illustrative, and various modifications may exist in the combination of their constituent elements or processing procedures, and such modifications are also within the scope of the present disclosure.

[0126] For example, the fourth embodiment may be combined with the second embodiment. In this case, when the i-th image Pi is located near the j-th image Pj, the sizes of the i-th image Pi and the j-th image Pj are greater than the size threshold, and the illuminance is greater than the first threshold Th1, the control circuit 20 turns on the i-th light source group Gi and the first sub-light source group GAi composed of the light sources 16 located between the i-th light source group Gi and the j-th light source group Gj in the i-th peripheral light source group OGi. That is, Fig.15 In the example of , the two first sub-light source groups GA1 on the left and the two first sub-light source groups GA4 on the right are turned off. In addition, the second, third and fourth embodiments may be combined.

[0127] One aspect of the present disclosure is as follows.

[0128] [Project 1]

[0129] A display device, comprising:

[0130] The display panel displays a first image in a first image area in the display area.

[0131] a backlight, which is located at the back of the display panel and irradiates light to the display panel,

[0132] an illumination sensor that detects the illumination of incident light, and

[0133] a control circuit for controlling the backlight according to the illumination;

[0134] The backlight has a plurality of light sources arranged in a matrix;

[0135] The control circuit

[0136] When the illuminance is less than a first threshold value as a predetermined value, a first light source group consisting of at least one light source overlapping with the first image area when viewed from a normal direction of the display panel among the plurality of light sources is turned on,

[0137] When the illuminance is equal to or higher than the first threshold, at least one of the first light source group and the first peripheral light source group including light sources located peripherally of the first light source group among the plurality of light sources is turned on.

[0138] According to this scheme, when the illuminance is above the first threshold, in addition to the first light source group overlapping with the first image area, the peripheral light sources of the first light source group are also lit, thereby increasing the brightness of the first image area compared to the case where only the first light source group is lit.

[0139] [Project 2]

[0140] The display device according to item 1, wherein:

[0141] The control circuit

[0142] When the illuminance is less than the first threshold, the first light source group is lit at a brightness which is higher as the illuminance increases and is less than a predetermined brightness,

[0143] When the illuminance is equal to or greater than the first threshold, the first light source group is turned on at the predetermined brightness.

[0144] In this case, when the illuminance is lower than the first threshold value, the brightness of the first image area can be smoothly changed according to the illuminance.

[0145] [Item 3]

[0146] The display device according to item 1 or 2, wherein:

[0147] When the illuminance is equal to or greater than the first threshold value, the control circuit turns on the at least one light source in the first peripheral light source group at a brightness that increases as the illuminance increases.

[0148] In this case, when the illuminance is equal to or greater than the first threshold, the brightness of the first image area can be smoothly changed according to the illuminance.

[0149] [Item 4]

[0150] The display device according to any one of items 1 to 3, wherein:

[0151] The control circuit

[0152] When the illuminance is equal to or greater than the first threshold value and less than a second threshold value which is a predetermined value, the first light source group and the first group which is a part of the first peripheral light source group are turned on,

[0153] When the illuminance is equal to or greater than the second threshold, the first light source group, the first group, and a second group different from the first group and being a part of the first peripheral light source group are turned on.

[0154] In this case, when the illuminance is equal to or greater than the first threshold, the brightness of the first image area can be changed smoothly.

[0155] [Item 5]

[0156] The display device according to any one of items 1 to 4, wherein:

[0157] The control circuit

[0158] When the importance of the first image is less than an importance threshold and the illuminance is greater than or equal to the first threshold, the first light source group and a first sub-light source group as a part of the first peripheral light source group are turned on,

[0159] When the importance of the first image is greater than or equal to the importance threshold and the illuminance is greater than or equal to the first threshold, the first light source group, the first sub-light source group, and a second sub-light source group different from the first sub-light source group and being a part of the first peripheral light source group are lit.

[0160] In this case, when the illuminance is equal to or greater than the first threshold, when the importance of the first image is equal to or greater than the importance threshold, the brightness of the first image region can be increased compared to a case where the importance is less than the importance threshold.

[0161] [Item 6]

[0162] The display device according to any one of items 1 to 4, wherein:

[0163] The control circuit

[0164] When the importance of the first image is less than an importance threshold and the illuminance is greater than the first threshold, the first light source group is lit at maximum brightness, and at least one light source in the first peripheral light source group is lit at a brightness that increases as the illuminance increases.

[0165] When the importance of the first image is equal to or greater than the importance threshold and the illuminance is equal to or greater than the first threshold, the at least one light source in the first light source group and the first peripheral light source group is lit at maximum brightness.

[0166] In this case, when the illuminance is equal to or greater than the first threshold, when the importance of the first image is equal to or greater than the importance threshold, the brightness of the first image region can be increased compared to a case where the importance is less than the importance threshold.

[0167] [Item 7]

[0168] The display device according to any one of items 1 to 4, wherein:

[0169] The control circuit

[0170] When the size of the first image is greater than or equal to a size threshold and the illuminance is greater than or equal to the first threshold, the first light source group and a first sub-light source group as a part of the first peripheral light source group are turned on,

[0171] When the size of the first image is smaller than the size threshold and the illuminance is greater than or equal to the first threshold, the first light source group, the first sub-light source group, and a second sub-light source group different from the first sub-light source group and being a part of the first peripheral light source group are lit.

[0172] In this case, when the size of the first image is equal to or larger than the size threshold, the brightness of the first image region can be increased, and an increase in power consumption can be suppressed.

[0173] [Item 8]

[0174] The display device according to any one of items 1 to 4, wherein:

[0175] The display panel displays a second image in a second image area in the display area;

[0176] The control circuit

[0177] When the illuminance is less than the first threshold, a second light source group consisting of at least one light source overlapping with the second image area when viewed from the normal direction of the display panel among the plurality of light sources is turned on,

[0178] When the illuminance is equal to or greater than the first threshold, lighting at least one light source of the second light source group and a second peripheral light source group consisting of light sources located on the periphery of the second light source group among the plurality of light sources;

[0179] The control circuit determines, based on the positional relationship between the first image and the second image, a light source included in the first peripheral light source group and the second peripheral light source group to be turned on when the illuminance is equal to or greater than the first threshold.

[0180] In this case, when the illuminance is equal to or higher than the first threshold, the light source corresponding to the positional relationship between the first image and the second image can be turned on.

[0181] [Item 9]

[0182] The display device according to item 8, wherein:

[0183] The control circuit determines to light up a light source located between the first light source group and the second light source group in the first peripheral light source group when the first image is located near the second image.

[0184] In this case, it is possible to increase the brightness of the first image area and the second image area and suppress an increase in power consumption.

[0185] [Industrial Applicability]

[0186] The present disclosure can be utilized in a display device.

[0187] [Explanation of Reference Numerals]

[0188] 1 ...display device, 12 ...display panel, 14 ...backlight, 16 ...light source, 20 ...control circuit, 22 ...illuminance sensor.

Claims

1. A display device, comprising: The display panel displays a first image in a first image area in the display area. a backlight, which is located at the back of the display panel and irradiates light to the display panel, an illumination sensor that detects the illumination of incident light, and a control circuit for controlling the backlight according to the illumination; The backlight has a plurality of light sources arranged in a matrix; The control circuit When the illuminance is less than a first threshold value as a predetermined value, a first light source group consisting of at least one light source overlapping with the first image area when viewed from a normal direction of the display panel among the plurality of light sources is turned on, When the illuminance is equal to or higher than the first threshold, at least one of the first light source group and the first peripheral light source group including light sources located peripherally of the first light source group among the plurality of light sources is turned on.

2. The display device according to claim 1, wherein: The control circuit When the illuminance is less than the first threshold, the first light source group is lit at a brightness which is higher as the illuminance increases and is less than a predetermined brightness, When the illuminance is equal to or greater than the first threshold, the first light source group is turned on at the predetermined brightness.

3. The display device according to claim 1 or 2, wherein: When the illuminance is equal to or greater than the first threshold value, the control circuit turns on the at least one light source in the first peripheral light source group at a brightness that increases as the illuminance increases.

4. The display device according to claim 1 or 2, wherein: The control circuit When the illuminance is equal to or greater than the first threshold value and less than a second threshold value which is a predetermined value, the first light source group and the first group which is a part of the first peripheral light source group are turned on, When the illuminance is equal to or greater than the second threshold, the first light source group, the first group, and a second group different from the first group and being a part of the first peripheral light source group are turned on.

5. The display device according to claim 1 or 2, wherein: The control circuit When the importance of the first image is less than an importance threshold and the illuminance is greater than or equal to the first threshold, the first light source group and a first sub-light source group as a part of the first peripheral light source group are turned on, When the importance of the first image is greater than or equal to the importance threshold and the illuminance is greater than or equal to the first threshold, the first light source group, the first sub-light source group, and a second sub-light source group different from the first sub-light source group and being a part of the first peripheral light source group are lit.

6. The display device according to claim 1 or 2, wherein: The control circuit When the importance of the first image is less than an importance threshold and the illuminance is greater than the first threshold, the first light source group is lit at maximum brightness, and at least one light source in the first peripheral light source group is lit at a brightness that increases as the illuminance increases. When the importance of the first image is equal to or greater than the importance threshold and the illuminance is equal to or greater than the first threshold, the at least one light source in the first light source group and the first peripheral light source group is turned on at maximum brightness.

7. The display device according to claim 1 or 2, wherein: The control circuit When the size of the first image is greater than or equal to a size threshold and the illuminance is greater than or equal to the first threshold, the first light source group and a first sub-light source group as a part of the first peripheral light source group are turned on, When the size of the first image is smaller than the size threshold and the illuminance is greater than or equal to the first threshold, the first light source group, the first sub-light source group, and a second sub-light source group different from the first sub-light source group which is a part of the first peripheral light source group are turned on.

8. The display device according to claim 1 or 2, wherein: The display panel displays a second image in a second image area in the display area; The control circuit When the illuminance is less than the first threshold, a second light source group consisting of at least one light source overlapping with the second image area when viewed from the normal direction of the display panel among the plurality of light sources is turned on, When the illuminance is equal to or greater than the first threshold, lighting at least one light source of the second light source group and a second peripheral light source group consisting of light sources located on the periphery of the second light source group among the plurality of light sources; The control circuit determines, based on the positional relationship between the first image and the second image, a light source included in the first peripheral light source group and the second peripheral light source group to be turned on when the illuminance is equal to or greater than the first threshold.

9. The display device according to claim 8, wherein: The control circuit determines to light up a light source located between the first light source group and the second light source group in the first peripheral light source group when the first image is located near the second image.

Images