Display device

Abstract

This display device comprises: a first panel which is a self-luminous type image display panel; and a second panel which is a self-luminous type image display panel of a type different from that of the first panel. A first display region, which is a region where images are displayed on the first panel, and a second display region, which is a region where images are displayed on the second panel, overlap with each other. The first display region is located on the display surface side of the second display region. The first display region includes a translucent region through which light outputted from the second display region can pass.

Description

display device

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

[0002] BACKGROUND ART Display devices using organic light-emitting diode (OLED) panels that include pixels made up of organic light-emitting diodes (OLEDs) that utilize the light-emitting phenomenon caused by organic electroluminescence (EL) are known (see, for example, Patent Document 1).

[0003] JP 2010-153126 A

[0004] OLEDs tend to have a shorter lifespan than inorganic light-emitting elements. Here, "lifespan" refers to the time during which light can be emitted continuously at a predetermined luminance or higher. In particular, the longer an OLED is illuminated at the maximum luminance it is physically capable of emitting light at or near that maximum luminance, the shorter its lifespan tends to become. Therefore, attempts to extend the lifespan of an OLED panel have limited the luminance of the display output, making it difficult to achieve high-luminance display output.

[0005] In particular, display devices that are required to support HDR (High Dynamic Range) require a wider range of brightness (dynamic range) than the conventional SDR (Standard Dynamic Range). It has been difficult for conventional OLED panels to simultaneously support such a required wider dynamic range and extend the life of the display device.

[0006] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a display device that can more easily achieve both compatibility with a wider dynamic range and an extended lifespan of the display device.

[0007] A display device according to one aspect of the present disclosure comprises a first panel which is a self-luminous image display panel and a second panel which is a self-luminous image display panel of a different type from the first panel, wherein a first display area in which an image is displayed on the first panel and a second display area in which an image is displayed on the second panel overlap, the first display area being located on the display surface side of the second display area, and the first display area being provided with a translucent area that can transmit light output from the second display area.

[0008] FIG. 1 is a schematic diagram showing the main components of a display device according to an embodiment. FIG. 2 is a schematic diagram showing the main components of a first panel when viewed from a planar perspective. FIG. 3 is a schematic diagram showing the main components of a second panel when viewed from a planar perspective. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2. FIG. 5 is a schematic diagram showing the main functional components of an image processing circuit. FIG. 6 is a diagram showing an image as an example of a display output mode corresponding to image data. FIG. 7 is a schematic diagram showing, in first and second examples, the relationship between the display output mode by the first panel, the display output mode by the second panel, and the display output mode by a display device in which the first and second panels that perform these display outputs are overlapped in a third direction. FIG. 8 is a graph showing an example of the relationship between the input value of an input signal and luminance proportional to the input value. FIG. 9 is a graph showing the relationship between a first signal OP1 and a second signal OP2 when the relationship between the input value and luminance shown in FIG. 8 holds. FIG. 10 is a graph showing an example of the relationship between the input value of an input signal and the luminance of a display device. Fig. 11 is a graph showing the relationship between the first signal OP1 and the second signal OP2 when the relationship between the input value and the luminance shown in Fig. 10 holds. Fig. 12 is a diagram showing an example of the configuration of a first pixel provided on the first panel. Fig. 13 is a diagram showing an example of the configuration of a pixel provided on the first panel. Fig. 14 is a diagram showing an example of the configuration of a pixel provided on the first panel. Fig. 15 is a schematic diagram showing the main configuration of the second panel when viewed from a planar perspective.

[0009] Each embodiment of the present disclosure will be described below with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present disclosure. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] 1 is a schematic diagram showing the main configuration of a display device 1 according to an embodiment. The display device 1 includes a first panel 10, a second panel 30, and a circuit board 50.

[0011] FIG. 2 is a schematic diagram showing the main configuration of the first panel 10 when viewed from a planar viewpoint. The planar viewpoint is a viewpoint in which a plane along the first direction Dx and the second direction Dy is viewed from the front. The first panel 10 is a self-luminous image display panel. Specifically, the first panel 10 is an OLED panel. As shown in FIGS. 1 and 2 , the first panel 10 has a first display area 20. A plurality of first pixels Pix are two-dimensionally arranged in the first display area 20.

[0012] In the following description, one of two directions along a plane parallel to the first display region 20 is referred to as a first direction Dx, and the other is referred to as a second direction Dy. The first direction Dx and the second direction Dy are orthogonal to each other. The direction orthogonal to both the first direction Dx and the second direction Dy is referred to as a third direction Dz. A user viewing an image displayed and output by the display device 1 views the image from the first panel 10 side in the third direction Dz, where the first panel 10 and the second panel 30 face each other. Hereinafter, in the relative facing relationship between the first panel 10 and the second panel 30, the first panel 10 side is referred to as the display surface side FS, and the second panel 30 side is referred to as the rear side RS.

[0013] The multiple unit regions 21 shown in FIG. 2 are arranged in a matrix along the first direction Dx and the second direction Dy. Each unit region 21 includes a first pixel Pix and a light-transmitting portion 25. The first pixel Pix includes a first sub-pixel Rpix, a second sub-pixel Gpix, and a third sub-pixel Bpix. The first sub-pixel Rpix, the second sub-pixel Gpix, and the third sub-pixel Bpix are sub-pixels of the first pixel Pix. The first sub-pixel Rpix, the second sub-pixel Gpix, and the third sub-pixel Bpix are each configured to generate a light emission phenomenon by organic EL. The first sub-pixel Rpix is ​​configured to be capable of outputting red (R) light. The second sub-pixel Gpix is ​​configured to be capable of outputting green (G) light. The third sub-pixel Bpix is ​​configured to be capable of outputting blue (B) light.

[0014] Furthermore, each unit region 21 includes a light-transmitting portion 25. The light-transmitting portion 25 functions as a light-transmitting region that transmits light from the second panel 30. Therefore, the region in which the light-transmitting portion 25 is provided can be considered an apparent opening in the light path. The light-transmitting portion 25 has a rectangular shape in a plan view, with its longitudinal direction extending along the first direction Dx. The unit region 21 shown in FIG. 3 is a rectangular region, in which a first pixel Pix and the light-transmitting portion 25 are arranged adjacent to each other in the second direction Dy. The first pixel Pix is ​​a pixel of the first panel 10 in which a first sub-pixel Rpix, a third sub-pixel Bpix, and a second sub-pixel Gpix are arranged in the first direction Dx and have a rectangular shape in a plan view, with their longitudinal directions extending along the second direction Dy. Furthermore, the light-transmitting portion 25 is located between the first pixels Pix adjacent to each other in the second direction Dy.

[0015] In Figure 2, only the unit areas 21 arranged at the four corners of the rectangular first display area 20 are marked with symbols, but the unit areas 21 have similar configurations arranged in a matrix along the first direction Dx and the second direction Dy between the four corners, and each includes a first pixel Pix and a translucent portion 25.

[0016] 2 , a frame region 23 is provided around the first display region 20. The frame region 23 is provided with wiring connected to the first pixels Pix, a DDIC (Display Driver Integrated Circuit) 11, a wiring unit 12, and the like. The DDIC 11 is a circuit that controls the operation of each sub-pixel of the multiple first pixels Pix in response to a signal provided from an image processing circuit 60 provided on the circuit board 50. The wiring unit 12 is a flexible printed circuit (FPC) on which wiring and the like between the first panel 10 and the circuit board 50 are formed.

[0017] FIG. 3 is a schematic diagram showing the main components of the second panel 30 when viewed from a plan view. The second panel 30 is a self-luminous image display panel that is different from the first panel 10. Specifically, the second panel 30 is an image display panel in which pixels are configured with inorganic light-emitting elements, such as a mini LED display. As shown in FIGS. 1 and 3 , the second panel 30 has a second display area 40. A plurality of second pixels 41 are two-dimensionally arranged in the second display area 40. The plurality of second pixels 41 shown in FIG. 3 are arranged in a matrix along the first direction Dx and the second direction Dy.

[0018] Each second pixel 41 includes a first sub-pixel 41R, a second sub-pixel 41G, and a third sub-pixel 41B. The first sub-pixel 41R, the second sub-pixel 41G, and the third sub-pixel 41B are sub-pixels of the second pixel 41G. The first sub-pixel 41R, the second sub-pixel 41G, and the third sub-pixel 41B are light-emitting elements that function as light-emitting diodes (LEDs). The first sub-pixel 41R is configured to be able to output red (R) light. The second sub-pixel 41G is configured to be able to output green (G) light. The third sub-pixel 41B is configured to be able to output blue (B) light.

[0019] 3 , a frame region 43 is provided around the second display region 40. The frame region 43 is provided with a wiring section 32 and the like. The wiring section 32 is an FPC on which wiring and the like are formed between the second panel 30 and the circuit board 50. The wiring section 12 and the wiring section 32 are flexible. Although not shown, the second panel 30 may be provided with an operation control circuit such as the DDIC 11 in the first panel 10. This circuit controls the operation of each sub-pixel of the plurality of second pixels 41.

[0020] The first panel 10 and the first display area 20 are provided so that the first display area 20 of the first panel 10 and the second display area 40 of the second panel 30 overlap in a plan view. Here, the first panel 10 is located on the display surface side FS of the second panel 30. Therefore, the first display area 20 is located on the display surface side FS of the second display area 40.

[0021] As shown by comparing FIGS. 2 and 3 , the second pixel 41 is larger in size from a planar perspective than the unit region 21 containing the first pixel Pix. Specifically, in the case of a combination of the first panel 10 shown in FIG. 2 and the second panel 30 shown in FIG. 3 , one second pixel 41 is arranged in the second display region 40 of the second panel 30 within an area in which nine (=3 × 3) unit regions 21 are arranged in the first display region 20 of the first panel 10. Therefore, in the case of a combination of the first panel 10 shown in FIG. 2 and the second panel 30 shown in FIG. 3 , the ratio of the size of the unit region 21 to the size of the second pixel 41 is 1:9. In other words, the ratio of the number of unit regions 21 to the number of second pixels 41 is 9:1. Therefore, in the embodiment described with reference to FIGS. 2 and 3 , the number of second pixels 41 per unit area of ​​the second panel 30 can be said to be smaller than the number of first pixels Pix per unit area of ​​the first panel 10. The unit area here refers to, for example, the area of ​​the range in which one second pixel 41 is provided, but regardless of which range within the area where the first display area 20 and the second display area 40 overlap from a planar perspective, the same relationship holds between the number of second pixels 41 per unit area of ​​the second panel 30 and the number of first pixels Pix per unit area of ​​the first panel 10.

[0022] 3, only the second pixels 41 arranged at the four corners of the rectangular second display region 40 are denoted by reference numerals, but the second pixels 41 are similarly configured and arranged in a matrix form between the four corners along the first direction Dx and the second direction Dy, and each of the second pixels 41 includes a first sub-pixel 41R, a second sub-pixel 41G, and a third sub-pixel 41B. Furthermore, each of the second pixels 41 overlaps with nine (=3 × 3) unit regions 21 when viewed from a plan view.

[0023] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. The first panel 10 has a configuration for causing an organic EL light emission phenomenon between two light-transmitting substrates, a first substrate 13 and a second substrate 14. This configuration includes a light-emitting layer 19, an anode 17 and a cathode 18 that face each other in the third direction Dz with the light-emitting layer 19 therebetween, a switching element 16 for controlling the voltage application to the light-emitting layer 19, and the like.

[0024] More specifically, the first panel 10 includes a first substrate 13 on the rear side RS and a second substrate 14 on the display surface side FS, which face each other in the third direction Dz. The first substrate 13 and the second substrate 14 are, for example, glass substrates, but may also be light-transmitting substrates made of other materials. A laminated structure is formed between the first substrate 13 and the second substrate 14, in which a circuit layer 15, an anode 17, a light-emitting layer 19, and a cathode 18 are stacked in this order from the first substrate 13 side toward the second substrate 14 side. The circuit layer 15 includes a semiconductor layer for forming a switching element 16, multiple insulating layers, and multiple electrode layers. These multiple electrode layers are provided to form the source, drain, and gate electrodes of the switching element 16. The anode 17 is connected to the source or drain of the switching element 16. The anode 17 is also connected to a potential line via the switching element 16. When the potential of the potential line is applied to the anode 17 while the source and drain of the switching element 16 are connected, a light emitting phenomenon occurs in the light emitting layer 19 according to the potential difference between the anode 17 and the cathode 18. Therefore, a subpixel such as the second subpixel Gpix including the anode 17, the cathode 18, and the light emitting layer 19 functions as an OLED. An OLED is a light emitting element that constitutes a self-luminous image display panel.

[0025] The anode 17 is a non-transparent electrode. Specifically, the anode 17 is an electrode formed from a material such as copper or aluminum, but the specific material may be changed as appropriate. The cathode 18 is a transparent electrode. Specifically, the cathode 18 is an electrode formed from a transparent conductor such as indium tin oxide (ITO), but the specific material may be changed as appropriate.

[0026] Although the second subpixel Gpix is ​​illustrated in FIG. 4 , the first subpixel Rpix and the third subpixel Bpix are structurally similar to the second subpixel Gpix. The first subpixel Rpix, the second subpixel Gpix, and the third subpixel Bpix are configured to emit light of different colors by using different organic materials contained in the light-emitting layers 19. The light-emitting layer 19 of the first subpixel Rpix is ​​formed using an organic material whose peak wavelength is perceived as red (R). The light-emitting layer 19 of the second subpixel Gpix is ​​formed using an organic material whose peak wavelength is perceived as green (G). The light-emitting layer 19 of the third subpixel Bpix is ​​formed using an organic material whose peak wavelength is perceived as blue (B). Examples of such organic materials include phosphorescent materials and fluorescent materials.

[0027] 2 and 4 , each unit region 21 of the first panel 10 includes a light-transmitting portion 25. The light-transmitting portion 25 is formed of a light-transmitting body that penetrates the circuit layer 15 in the third direction Dz. The light-transmitting body is made of, for example, a light-transmitting resin, but may be made of other materials as long as they function similarly. Note that the insulating layer 17a, which is located on the cathode 18 side of the circuit layer 15 and is in the same layer as the anode 17, is made of a light-transmitting insulator.

[0028] In this way, a plurality of unit areas 21 are arranged within the first display area 20, and each unit area 21 is provided with a light-transmitting portion 25 that can transmit light output from the second panel 30. Therefore, it can be said that the first display area 20 is provided with a light-transmitting area that can transmit light output from the second display area 40 of the second panel 30. The light-transmitting portion 25 functions as this light-transmitting area.

[0029] The second panel 30 has an LED and a configuration for applying a voltage to the LED between two light-transmitting substrates, a first substrate 33 and a second substrate 34. The configuration includes a light-emitting element 39, a switching element 36 for controlling the application of a voltage to an anode 37 of the light-emitting element 39, and the like.

[0030] More specifically, the second panel 30 has a second substrate 34 provided on the display surface side FS and a first substrate 33 provided on the rear side RS, which face each other in the third direction Dz. The first substrate 33 and the second substrate 34 are, for example, glass substrates, but may also be light-transmitting substrates made of other materials. A layered structure is formed between the first substrate 33 and the second substrate 34, in which a circuit layer 35, an anode 37, a light-emitting element 39, and a phosphor 31 are stacked in this order from the first substrate 33 side toward the second substrate 34 side.

[0031] The circuit layer 35 includes a semiconductor layer for forming the switching element 36, a plurality of insulating layers, and a plurality of electrode layers. The plurality of electrode layers are provided for forming the respective electrodes of the source, drain, and gate included in the switching element 36. The anode 37 is connected to the anode of the light-emitting element 39. The anode 37 is also connected to a potential line via the switching element 36. When the potential of the potential line is applied to the anode 37 while the source and drain of the switching element 36 are connected, the light-emitting element 39 emits light.

[0032] The light-emitting element 39 is an LED known as a mini-LED. A mini-LED is, for example, an LED in which the diameter of the light-emitting point that produces the light-emitting phenomenon of an LED is within the dimensions of 50 micrometers (μm) or more and 200 micrometers (μm) or less, but any other element of a similar size may be used as the light-emitting element 39. A smaller micro-LED may also be used as the light-emitting element 39. The phosphor 31 is an illuminant that receives light from the light-emitting element 39 and emits light. In other words, a sub-pixel of the second pixel 41, such as the second sub-pixel 41G, causes the phosphor 31 to emit light using the light from the light-emitting element 39.

[0033] 4 , the width of the phosphor 31 is wider than the width of the light-emitting element 39 at least in the second direction Dy. Within the range in which the phosphor 31 is provided, an insulating layer 38 is provided in a range on the light-emitting element 39 side in the third direction Dz, where the light-emitting element 39 is not provided. The thickness of the insulating layer 38 in the third direction Dz is equal to the thickness of the light-emitting element 39 in the third direction Dz.

[0034] Although FIG. 4 illustrates the second subpixel 41G as an example, the first subpixel 41R and the third subpixel 41B are structurally similar to the second subpixel 41G. The first subpixel 41R, the second subpixel 41G, and the third subpixel 41B are configured to emit light of different colors by using different forbidden band materials to form the light-emitting element 39. For example, the first subpixel 41R may employ aluminum gallium arsenide (AlGaAs) as the forbidden band material. The second subpixel 41G and the third subpixel 41B may employ indium gallium nitride (InGaN) as the forbidden band material. The difference in the color of light emitted by the second subpixel 41G and the third subpixel 41B can be achieved by varying the ratio of indium (In) to gallium (Ga) contained in the materials. All of the materials for the light-emitting element 39 listed above are inorganic compounds. Therefore, the light-emitting element 39 is an inorganic light-emitting element. The second panel 30, which uses the light from the light-emitting elements 39 as the light from the second pixels 41, is an image display panel in which pixels are configured with inorganic light-emitting elements.

[0035] The material of the phosphor 31 may be selected appropriately depending on the color of light emitted by the light emitting element 39 overlapping in the third direction Dz.

[0036] In the embodiment, as shown in Fig. 4, a diffuser 70 may be provided between the first panel 10 and the second panel 30. The diffuser 70 is an optical member that diffuses light from the second panel 30. This makes it easier to widen the viewing angle of the display device 1 that uses light from the second panel 30 for display output. Note that the diffuser 70 may be omitted.

[0037] Next, the image data displayed and output by the display device 1 will be described. The image data includes a plurality of pixel data. The plurality of pixel data is individually assigned to each of regions (pixel regions) obtained by dividing a two-dimensional surface into a matrix. In other words, the image data is data in which a plurality of pixel regions are arranged in a matrix. For example, image data known as full HD (High Definition) image data is image data that includes a 1920 x 1080 pixel region, in which 1920 pixel regions are arranged in one of two orthogonal directions and 1080 pixel regions are arranged in the other of the two directions.

[0038] Image data is data in which individual pixel data is assigned to multiple pixel regions. The pixel data is, for example, data representing RGB color. RGB color is expressed as a combination of a gradation value indicating the brightness of red (R), a gradation value indicating the brightness of green (G), and a gradation value indicating the brightness of blue (B). Here, for convenience, RGB color is written as (R, G, B) = (m, n, p). m is the gradation value indicating the brightness of red (R). n is the gradation value indicating the brightness of green (G). p is the gradation value indicating the brightness of blue (B). Gradation values ​​such as m, n, and p take values ​​within a range corresponding to a predetermined number of bits. For example, if the gradation value is 8 bits, m, n, and p are each integers between 0 and 255. Furthermore, when we refer to color components indicated by RGB color, we mean the gradation value of the color expressed by (R, G, B) = (m, n, p), that is, (m, n, p).

[0039] Image data is input from the outside as an input signal IP to the display device 1. Specifically, the input signal IP is input to the image processing circuit 60 via an FPC provided on the circuit board 50, such as the wiring portion 51 shown in FIG.

[0040] Next, image processing related to display output by a combination of the first panel 10 and the second panel 30 will be described with reference to FIGS. 5 to 11. FIG.

[0041] 5 is a schematic diagram showing the main functional configuration of the image processing circuit 60. The image processing circuit 60 shown in FIG. 5 includes a signal processing unit 61 and a gamma processing unit 62. The signal processing unit 61 performs image processing to cause the first panel 10 and the second panel 30 to cooperate to produce a display output corresponding to image data input from the outside to the display device 1. Specifically, the signal processing unit 61 performs RGB color division processing. The RGB color division processing is a process in which a portion of the color components indicated by the RGB color is assigned to one of the first panel 10 or the second panel 30, and the remaining color components indicated by the RGB color from which the portion has been subtracted are assigned to the other of the first panel 10 or the second panel 30.

[0042] As a more specific first example, assume that, as part of the color components represented by RGB colors, color components of the RGB colors represented by (m, n, p) that are "less than 50% of the maximum brightness indicated by the gradation value" are assigned to the first panel 10, and color components of the RGB colors represented by (m, n, p) that are "greater than 50% of the maximum brightness indicated by the gradation value" are assigned to the second panel 30. For ease of understanding, the following description will be given on the assumption that the input value is proportional to the brightness of the display output of the display device 1. More specifically, in the following first and second examples (described in detail below), the input value of the input signal IP is proportional to the brightness of the display output generated by the display device 1 in response to the input value. In other words, the description assuming the proportionality between the input value and brightness ignores the relationship between the input and output due to gamma.

[0043] For the purposes of explaining the first example and the second example described below, three pixel data, namely, first pixel data, second pixel data, and third pixel data, are conveniently defined among the multiple pixel data included in the image data. The first pixel data, second pixel data, and third pixel data are pixel data assigned to different pixel regions. The first pixel data is assumed to represent (R, G, B) = (255, 255, 255). The second pixel data is assumed to represent (R, G, B) = (200, 100, 50). The third pixel data is assumed to represent (R, G, B) = (100, 50, 25). Furthermore, the highest gradation value in the image data including the first pixel data, second pixel data, and third pixel data is assumed to be 255. As described above, in the explanations of the first example and the second example described below, it is assumed that the gradation value is proportional to the luminance of the pixel.

[0044] In the first example, the upper limit of the gradation value that can be treated as a color component that is "50% or less of the maximum brightness indicated by the gradation value" is 127. Therefore, when the first example is applied, the signal processing unit 61 generates a first signal OP1 and a second signal OP2 from the first pixel data, with the first signal OP1 being a signal indicating an RGB color of (R, G, B) = (127, 127, 127) and the second signal OP2 being a signal indicating an RGB color of (R, G, B) = (128, 128, 128). The signal processing unit 61 provides a signal corresponding to the first signal OP1 to the first panel 10 and a signal corresponding to the second signal OP2 to the second panel 30. The sum of the first signal OP1 and the second signal OP2 corresponds to (R, G, B) = (255, 255, 255), which is equal to the RGB color indicated by the first pixel data.

[0045] Furthermore, when the first example is applied, the signal processing unit 61 generates a first signal OP1 and a second signal OP2 from the second pixel data, with the first signal OP1 being a signal indicating an RGB color of (R, G, B) = (127, 100, 50) and the second signal OP2 being a signal indicating an RGB color of (R, G, B) = (73, 0, 0). The signal processing unit 61 provides a signal corresponding to the first signal OP1 to the first panel 10 and a signal corresponding to the second signal OP2 to the second panel 30. Adding the first signal OP1 and the second signal OP2 together results in (R, G, B) = (200, 100, 50), which is equal to the RGB color indicated by the second pixel data.

[0046] Furthermore, when the first example is applied, the signal processing unit 61 generates a first signal OP1 and a second signal OP2 from the third pixel data, with the first signal OP1 being a signal indicating an RGB color of (R, G, B) = (100, 50, 25) and the second signal OP2 being a signal indicating an RGB color of (R, G, B) = (0, 0, 0). The signal processing unit 61 provides a signal corresponding to the first signal OP1 to the first panel 10 and a signal corresponding to the second signal OP2 to the second panel 30. Adding the first signal OP1 and the second signal OP2 together results in (R, G, B) = (100, 50, 25), which is equal to the RGB color indicated by the third pixel data.

[0047] As a second example different from the first example, assume that, as part of the color components indicated by the RGB color, among the color components of the RGB color represented by (m, n, p), color components that are "25% or less of the maximum luminance indicated by the gradation value" are assigned to the first panel 10, and among the color components of the RGB color represented by (m, n, p), color components that "exceed 25% of the maximum luminance indicated by the gradation value" are assigned to the second panel 30. In the second example, if the maximum gradation value is 255, the upper limit of the gradation value that can be treated as a color component that is "25% or less of the maximum luminance indicated by the gradation value" is 63.

[0048] When the second example is applied, the signal processing unit 61 generates a first signal OP1 and a second signal OP2 from the first pixel data, with the first signal OP1 being a signal indicating an RGB color of (R, G, B) = (63, 63, 63) and the second signal OP2 being a signal indicating an RGB color of (R, G, B) = (192, 192, 192). The signal processing unit 61 provides a signal corresponding to the first signal OP1 to the first panel 10 and a signal corresponding to the second signal OP2 to the second panel 30. Adding the first signal OP1 and the second signal OP2 together results in (R, G, B) = (255, 255, 255), which is equal to the RGB color indicated by the first pixel data.

[0049] Furthermore, when the second example is applied, the signal processing unit 61 generates a first signal OP1 and a second signal OP2 from the second pixel data, with the first signal OP1 being a signal indicating an RGB color of (R, G, B) = (63, 63, 50) and the second signal OP2 being a signal indicating an RGB color of (R, G, B) = (137, 37, 0). The signal processing unit 61 provides a signal corresponding to the first signal OP1 to the first panel 10 and a signal corresponding to the second signal OP2 to the second panel 30. Adding the first signal OP1 and the second signal OP2 together results in (R, G, B) = (200, 100, 50), which is equal to the RGB color indicated by the second pixel data.

[0050] Furthermore, when the second example is applied, the signal processing unit 61 generates a first signal OP1 and a second signal OP2 from the third pixel data, with the first signal OP1 being a signal indicating an RGB color of (R, G, B) = (63, 50, 25) and the second signal OP2 being a signal indicating an RGB color of (R, G, B) = (37, 0, 0). The signal processing unit 61 provides a signal corresponding to the first signal OP1 to the first panel 10 and a signal corresponding to the second signal OP2 to the second panel 30. Adding the first signal OP1 and the second signal OP2 together results in (R, G, B) = (100, 50, 25), which is equal to the RGB color indicated by the third pixel data.

[0051] The above-mentioned first and second examples will be described with reference to FIGS. 6 and 7 when they are actually reflected in the tone value control of image data. FIG.

[0052] 6 is a diagram showing an image 91 as an example of a display output mode corresponding to image data. The image 91 is an image in which the color components indicated by the RGB colors are reflected as they are in each of a plurality of pixel regions included in the image data. In other words, the image 91 can be said to be an image in which the color components indicated by the RGB colors are reflected 100%.

[0053] 7 is a schematic diagram showing, in a first example and a second example, the relationship between the display output mode by the first panel 10, the display output mode by the second panel 30, and the display output mode by the display device 1 in which the first panel 10 and the second panel 30 that perform these display outputs are overlapped in the third direction Dz. The first layer (OLED) in FIG. 7 shows the display output mode by the first panel 10. The second layer (mini LED) in FIG. 7 shows the display output mode by the second panel 30. The output image in FIG. 7 shows the display output mode by the display device 1 in which the first panel 10 and the second panel 30 are overlapped in the third direction Dz.

[0054] 7 , a first image 92 is output by the first panel 10, and a second image 93 is output by the second panel 30, resulting in an overall image 94 being output by the display device 1. The first image 92 is an image made up of color components of the image 91 that are "less than 50% of the maximum brightness indicated by the gradation value." The second image 93 is an image made up of color components of the image 91 that are "greater than 50% of the maximum brightness indicated by the gradation value." The first image 92 and the second image 93 overlap, resulting in an overall image 94 that is visually recognized by the user of the display device 1 that is substantially the same as image 91.

[0055] 7 , a first image 95 is output by the first panel 10, and a second image 96 is output by the second panel 30, resulting in an overall image 97 being output by the display device 1. The first image 95 is an image made up of color components of the image 91 that are "25% or less of the maximum brightness indicated by the gradation value." The second image 96 is an image made up of color components of the image 91 that are "more than 25% of the maximum brightness indicated by the gradation value." The first image 95 and the second image 96 overlap, resulting in an overall image 97 that is visually recognized by the user of the display device 1 that is substantially the same as image 91.

[0056] As described with reference to FIGS. 2 and 3 , in the embodiment, the ratio between the number of unit regions 21 and the number of second pixels 41 is 9:1. Therefore, the number of second pixels 41 of the second panel 30 provided within a range in which 3×3=9 pixel data are assigned to the first panel 10 is 1. Therefore, in the embodiment, there may be a case in which the color components assigned to the first panel 10 do not simply correspond to the color components assigned to the second panel 30. Therefore, in the embodiment, the signal processing unit 61 further performs peak processing on the color components assigned to the second panel 30. In the peak processing, the maximum gradation values ​​indicated by the plurality of pixel data that formed the basis of the first signal OP1 assigned to the plurality of first pixels Pix that overlap one second pixel 41 in the third direction Dz are individually extracted for red (R), green (G), and blue (B). Furthermore, in peak processing, the RGB color obtained by combining the gradation values ​​of red (R), green (G), and blue (B) extracted in this manner is treated as indicating the color component assigned to the one second pixel 41.

[0057] As an example, in this embodiment, assume that, of nine first pixels Pix overlapping one second pixel 41 in the third direction Dz, pixel data corresponding to one first pixel Pix indicates (R, G, B) = (200, 0, 0), pixel data corresponding to another first pixel Pix indicates (R, G, B) = (100, 150, 100), and pixel data corresponding to yet another first pixel Pix indicates (R, G, B) = (50, 50, 255). In this case, the pixel data corresponding to the remaining six first pixels Pix indicate (R, G, B) = (0, 0, 0). In this case, the highest red (R) gradation value indicated by the pixel data corresponding to the nine first pixels Pix is ​​200. In this case, the highest green (G) gradation value indicated by the pixel data corresponding to the nine first pixels Pix is ​​150. In this case, the highest blue (B) gradation value indicated by the pixel data corresponding to the nine first pixels Pix is ​​255. Therefore, in this case, the signal processing unit 61 extracts 200 as the highest red (R) gradation value, 150 as the highest green (G) gradation value, and 255 as the highest blue (B) gradation value in peak processing. Furthermore, the signal processing unit 61 treats an RGB color combining the highest gradation values ​​of red (R), green (G), and blue (B) extracted in this manner, i.e., (R, G, B) = (200, 150, 255), as the RGB color indicated by the pixel data assigned to the second pixel 41 that overlaps with the nine first pixels Pix in the third direction Dz.

[0058] In this embodiment, the signal processing unit 61 applies peak processing and then performs the above-described RGB color division processing.

[0059] For example, in the first example, color components that "exceed 50% of the maximum luminance indicated by the gradation value" are assigned to the second panel 30. Therefore, in the first example, 127, which corresponds to "50% of the maximum luminance indicated by the gradation value," is subtracted from the gradation values ​​of each of red (R), green (G), and blue (B). Therefore, if the image data generated by peak processing is (R, G, B) = (200, 150, 255), the values ​​assigned to the second panel 30 are (R, G, B) = (73, 23, 128).

[0060] Furthermore, in the second example, color components that "exceed 25% of the maximum luminance indicated by the gradation value" are assigned to the second panel 30. Therefore, in the second example, 63, which corresponds to "25% of the maximum luminance indicated by the gradation value," is subtracted from the gradation values ​​of each of red (R), green (G), and blue (B). Therefore, if the image data generated by peak processing is (R, G, B) = (200, 150, 255), the values ​​assigned to the second panel 30 are (R, G, B) = (137, 87, 192).

[0061] FIG. 8 is a graph showing an example of the relationship between the input value of the input signal IP and the luminance proportional to the input value. The input value indicated by the horizontal axis in the graphs of FIG. 8 and the graphs of FIGS. 9, 10, and 11 described below is a general concept representing the gradation values ​​of red (R), green (G), and blue (B) included in the RGB color described above. For example, (R, G, B) = (0, 0, 0) is the minimum input value. Furthermore, when the gradation value is 8 bits, (R, G, B) = (255, 255, 255) is the maximum input value. The term "input value" is intended to indicate the value indicated by the input signal IP to the signal processing unit 61. Furthermore, the vertical axis of the graphs of FIGS. 8 to 11 represents the luminance of the display output from the entire display device 1 in which the first panel 10 and the second panel 30 overlap in the third direction Dz. In addition, in the explanations referring to Figures 8 to 11, it is assumed that color components that are "less than α% of the maximum brightness value" are assigned to the first panel 10, and color components that "exceed α% of the maximum brightness value" are assigned to the second panel 30.

[0062] 9 is a graph showing the relationship between the first signal OP1 and the second signal OP2 when the relationship between the input value and the luminance shown in FIG. 8 holds. The first signal OP1 is a signal generated by the signal processing unit 61 in response to the input signal IP and assigned to the first panel 10. The second signal OP2 is a signal generated by the signal processing unit 61 in response to the input signal IP and assigned to the second panel 30. In FIGS. 9 and 11, the magnitude of the values ​​reflected in the first signal OP1 and the second signal OP2 is represented along the vertical axis of the graph. In other words, the gradation value at which the luminance along the vertical axis is exhibited is reflected in the first signal OP1 and the second signal OP2, respectively.

[0063] In the examples shown in FIGS. 8 and 9 , the input value corresponding to "α% of the maximum brightness" is β. Therefore, as shown in FIG. 9 , all input values ​​equal to or less than β, corresponding to a brightness "α% or less of the maximum brightness," are assigned to the first panel 10. Furthermore, when the input value is proportional to the brightness, the first signal OP1 assigned to the first panel 10 is also proportional to the input value within a range of input values ​​equal to or less than β. That is, within a range of input values ​​equal to or less than β, the input signal and the first signal OP1 are substantially equal. On the other hand, since all input values ​​equal to or less than β, corresponding to a brightness "α% or less of the maximum brightness," are assigned to the first panel 10, the second signal OP2 assigned to the second panel 30 is the lowest value within a range of input values ​​equal to or less than β. In this embodiment, the second pixel 41 of the second panel 30 to which the second signal OP2 indicating the lowest value is applied does not emit light.

[0064] In the examples shown in FIGS. 8 and 9 , when the input value exceeds β, a luminance of "α% of the maximum luminance" is assigned to the first panel 10, and a luminance obtained by subtracting α (%) from the luminance percentage exceeding α is assigned to the second panel 30. Therefore, within a range where the input value exceeds β, the luminance obtained by the first signal OP1 is fixed at α. In other words, within a range where the input value exceeds β, the first signal OP1 becomes the same as the first signal OP1 when the input value is β. On the other hand, within a range where the input value exceeds β, the luminance obtained by subtracting α (%) from the luminance percentage exceeding α. Therefore, within a range where the input value exceeds β, the level of the second signal OP2 is proportional to the level of the luminance.

[0065] 8 and 9, it is assumed that the input value, the output corresponding to the input value, and the luminance are proportional to each other. However, in reality, in terms of the luminance due to the brightness of light perceived by humans, the input value, the output corresponding to the input value, and the luminance may not be proportional to each other. A case in which the input value, the output corresponding to the input value, and the luminance are not proportional to each other will be described with reference to FIGS.

[0066] FIG. 10 is a graph showing an example of the relationship between the input value of the input signal IP and the luminance of the display device 1. The graph shown in FIG. 10 is a so-called PQ gamma curve. The PQ gamma curve is a gamma curve that indicates the brightness of light per unit area visually recognized when a human views an image output by a display device such as the display device 1, within a range below a predetermined maximum luminance (e.g., 10,000 nits). Note that nits are equivalent to candelas per square meter (cd / m2). The maximum luminance value (100 percent (%): MAX) shown in FIGS. 8 and 10 is, for example, the predetermined maximum luminance, but may be a different maximum luminance.

[0067] Fig. 11 is a graph showing the relationship between the first signal OP1 and the second signal OP2 when the relationship between the input value and the luminance shown in Fig. 10 holds. In the graph shown in Fig. 10, in the relationship between the input value of the input signal IP and the luminance of the display device 1, within the range of input values ​​equal to or less than λ, the degree of increase in luminance in response to an increase in the input value is gentler than within the range of input values ​​exceeding λ. Also, in the graph shown in Fig. 10, the degree of increase in luminance in response to an increase in the input value becomes more pronounced as the input value increases, and this tendency is particularly pronounced within the range of input values ​​exceeding λ.

[0068] In the examples shown in FIGS. 10 and 11 , the input value corresponding to "α% of the maximum brightness" is λ. Therefore, as shown in FIG. 11 , all input values ​​equal to or less than λ, which correspond to a brightness equal to or less than α% of the maximum brightness, are assigned to the first panel 10 and reflected in the first signal OP1. In other words, RGB colors derived so as to establish the relationship between input values ​​and brightness shown in FIG. 10 are reflected in the first signal OP1. Information indicating the correspondence between such input values, the brightness corresponding to the input values, the RGB color gradation values ​​indicated by the pixel data for the first panel 10, and the brightness of the first panel 10 exhibited by the gradation values ​​is previously stored in the image processing circuit 60 as information accessible to the signal processing unit 61. The signal processing unit 61 derives the RGB color reflected in the first signal OP1 from the input value by referring to this information. Furthermore, within the range of input values ​​equal to or less than λ, the second signal OP2 assigned to the second panel 30 is the lowest value.

[0069] 10 and 11 , when the input value exceeds λ, a luminance corresponding to λ, which corresponds to a luminance of "α% of the maximum luminance value," is assigned to the first panel 10, and a luminance obtained by subtracting α (%) from the luminance of the percentage (%) exceeding α is assigned to the second panel 30. Therefore, within a range where the input value exceeds λ, the RGB colors derived so that the luminance by the first signal OP1 is fixed at α are reflected in the first signal OP1.

[0070] On the other hand, within a range where the input value exceeds λ, the second signal OP2 assumes a value corresponding to "the luminance of the percentage (%) obtained by subtracting α from the maximum luminance value (MAX)." Information indicating the correspondence between the input value for deriving the second signal OP2 for causing the second panel 30 to exhibit "the luminance of the percentage (%) obtained by subtracting α from the maximum luminance value (MAX)" and the luminance of the second panel 30 is held in advance by the image processing circuit 60 as information that can be referenced by the signal processing unit 61. The signal processing unit 61 derives the RGB color reflected in the second signal OP2 from the input value by referring to this information.

[0071] In the embodiment, the maximum luminance that the second pixel 41 of the second panel 30 can output is higher than the maximum luminance that the first pixel Pix of the first panel 10 can output. Specifically, the maximum luminance that the first pixel Pix of the first panel 10 can physically output as a light-emitting element is approximately 1,000 nits. On the other hand, the maximum luminance that the second pixel 41 of the second panel 30 can output is, for example, approximately 20,000 nits, which significantly exceeds 10,000 nits. Note that when the first display region 20 is viewed from a planar perspective, the translucent portion 25 occupies only a small portion of the area of ​​the first display region 20. Furthermore, it is extremely difficult to achieve 100% light transmittance through the translucent portion 25, and light attenuation may occur due to the properties of the material of the translucent portion 25 itself. For these reasons, the brightness reflected in the output as the luminance of the second pixel 41 is only a portion of the brightness that light from the OLED can inherently produce. Even when such a relationship between the light from the OLED and the luminance of the second pixel 41 is taken into consideration, the luminance of the second pixel 41 is equal to or greater than the luminance of the first pixel Pix.

[0072] Information indicating a value corresponding to α is held in the image processing circuit 60 as information that can be referenced by the signal processing unit 61. This information may be provided in a changeable manner. For example, this information may be changeable in response to an external input to the image processing circuit 60 via the wiring unit 51. In the graphs described with reference to FIGS. 10 and 11 , the value of α is, for example, 5. This value is obtained when the predetermined maximum luminance corresponding to the maximum assumed luminance value (100 percent (%): MAX) is assumed to be 10,000 nits. In other words, this value of α is determined assuming that the upper limit luminance when the first pixel Pix of the first panel 10 actually lights up is 500 nits.

[0073] As described above, in the embodiment, the maximum luminance that the first pixel Pix of the first panel 10 can physically output as a light-emitting element is approximately 1000 nits. In contrast, the upper limit luminance (500 nits) determined according to the value of α is significantly low. By determining α in this manner, it is easier to extend the life of the first pixel Pix of the first panel 10. As described above, the first pixel Pix of the second panel 30 lights up in response to an input value that requires a luminance exceeding "α% of the maximum luminance" during display output. Thus, in the embodiment, the first pixel Pix of the first panel 10 is controlled so that its upper limit luminance during display output is a predetermined luminance (500 nits) that is less than the maximum luminance that can be output (1000 nits). Among the second pixels 41 of the second panel 30, the second pixels 41 that overlap the first pixel Pix of the first panel 10 that lights up at the upper limit luminance light up during display output when the upper limit luminance alone is insufficient. Furthermore, the second pixels 41 of the second panel 30 that overlap with the first pixels Pix of the first panel 10 that light up at the upper limit luminance light up at a luminance corresponding to the input value, i.e., the difference between the luminance corresponding to the gradation value indicated by the input signal IP and the upper limit luminance. The "luminance corresponding to the difference between the luminance corresponding to the gradation value indicated by the input signal IP and the upper limit luminance" is, for example, the above-mentioned "luminance that is a percentage (%) obtained by subtracting α from the maximum luminance value (MAX)."

[0074] The above explanation is based on the assumption that no particular correction is required for the control of the first panel 10 and the second panel 30 based on the first signal OP1 and the second signal OP2. In reality, since the first panel 10 and the second panel 30 are panels that employ different display output methods, it is desirable to perform gamma curve correction corresponding to the panel characteristics on at least one of the panels.

[0075] In the embodiment, it is assumed that the gamma curve of the image data input by the input signal IP corresponds to the first panel 10 but does not correspond to the second panel 30. Therefore, as shown in FIG. 5 , in the embodiment, a gamma processing unit 62 is provided. The gamma processing unit 62 performs gamma correction taking into account the difference between the gamma curve of the image data input by the input signal IP and the gamma characteristics of the second panel 30. By undergoing gamma correction by the gamma processing unit 62, the second signal OP2 is corrected so as to more accurately reproduce the colors expected from the image data input by the input signal IP. The signal corresponding to the above-mentioned second signal OP2 is, for example, a signal in which the gamma correction by the gamma processing unit 62 is reflected in the second signal OP2.

[0076] Note that if the gamma curve of the image data input by the input signal IP corresponds to the second panel 30 but not to the first panel 10, a gamma processing unit 63 is provided instead of the gamma processing unit 62. The gamma processing unit 63 performs gamma correction taking into account the difference between the gamma curve of the image data input by the input signal IP and the gamma characteristics of the first panel 10. The signal corresponding to the first signal OP1 described above is, for example, a signal in which the gamma correction by the gamma processing unit 62 is reflected in the first signal OP1. Note that if the gamma curve of the image data input by the input signal IP corresponds to both the first panel 10 and the second panel 30, both the gamma processing unit 62 and the gamma processing unit 63 are provided. Note that if the gamma curve of the image data input by the input signal IP corresponds to the first panel 10, the signal corresponding to the first signal OP1 described above may be the first signal OP1. Furthermore, when the gamma curve of the image data input by the input signal IP corresponds to the second panel 30, the signal corresponding to the second signal OP2 described above may be the second signal OP2.

[0077] As described above, according to the embodiment, the display device 1 includes the first panel 10, which is a self-luminous image display panel, and the second panel 30, which is a self-luminous image display panel of a different type from the first panel 10. The first display area 20, in which an image is displayed on the first panel 10, and the second display area 40, in which an image is displayed on the second panel 30, overlap with each other. The first display area 20 is located on the display surface side FS of the second display area 40. The first display area 20 is provided with a light-transmitting portion 25 that functions as a light-transmitting area that can transmit light output from the second display area 40. This allows for both a higher-quality display output obtained by a self-luminous image display panel and ensuring brightness by utilizing both the pixels (first pixels Pix and second pixels 41) of the first panel 10 and the second panel 30. Therefore, cooperation between the first panel 10 and the second panel 30 makes it easier to accommodate a wider dynamic range and extend the life of the display device. That is, it is possible to more easily achieve a longer panel life than when trying to ensure the same brightness using only an OLED panel.

[0078] Furthermore, by using the first panel 10 as an OLED panel and the second panel 30 as an image display panel with pixels made up of inorganic light-emitting elements, it is possible to achieve both the high image quality of the OLED panel and the brightness achieved by using the OLED and inorganic light-emitting elements. Therefore, cooperation between the first panel 10 and the second panel 30 makes it easier to accommodate a wider dynamic range and extend the life of the display device. In other words, it is easier to extend the life of the panel than if the same brightness were to be achieved using only an OLED panel.

[0079] Furthermore, since the maximum brightness that can be output by the second pixel 41 of the second panel 30 is higher than the maximum brightness that can be output by the first pixel Pix of the first display area 20, the light from the second pixel 41 that outputs light to the display surface side FS through the translucent portion 25 that functions as a translucent area can more reliably contribute to improving the brightness of the display output.

[0080] Furthermore, by providing a light-transmitting portion 25 that functions as a light-transmitting region between a plurality of first pixels Pix provided in the first display region 20, it is possible to achieve both the display output of an image by the first panel 10 and the transmission of light from the second panel 30.

[0081] Furthermore, since the number of second pixels 41 per unit area of ​​the second panel 30 is smaller than the number of first pixels Pix per unit area of ​​the first panel 10, it becomes easier to reduce the manufacturing difficulty and cost required for the second panel 30.

[0082] Furthermore, by providing the diffusion plate 70 between the first panel 10 and the second panel 30 to diffuse light, the light from the second panel 30 can be more easily viewed over a wider range from the display surface side FS, which makes it easier to widen the viewing angle.

[0083] Furthermore, the first pixel Pix of the first panel 10 is controlled to have a predetermined brightness (e.g., 500 nits) that is less than the maximum brightness (e.g., 1000 nits) that can be output as the upper limit brightness during display output, and the second pixels 41 of the second panel 30 that overlap with the first pixel Pix of the first panel 10 that lights up at that upper limit brightness light up during display output when the brightness is insufficient with only the upper limit brightness, thereby making it possible to achieve both the output of a higher-resolution image by the first pixel Pix of the first panel 10 and the output of a brighter image that exceeds the upper limit brightness through cooperation between the first panel 10 and the second panel 30.

[0084] Furthermore, the second pixels 41 of the second panel 30 that overlap with the first pixels Pix of the first panel 10 that light up at the upper limit brightness light up at a brightness that corresponds to the difference between the brightness that corresponds to the gradation value indicated by the input signal IP (e.g., pixel data included in the image data) and the upper limit brightness of the first pixels Pix of the first panel 10, thereby clarifying the rules for when the second pixels 41 light up and enabling more precise display output control.

[0085] The above description has been given assuming a unit region 21 in which the first sub-pixel Rpix, the third sub-pixel Bpix, and the second sub-pixel Gpix, each having a rectangular shape with its longitudinal direction aligned along the second direction Dy, are aligned in the first direction Dx, and the light-transmitting portion 25 is provided adjacent to the first pixel Pix in which the first sub-pixel Rpix, the third sub-pixel Bpix, and the second sub-pixel Gpix are aligned in the second direction Dy, as shown in Fig. 3. However, the form of a partial region within the first display region 20 provided on the first panel 10 that includes pixels is not limited to the unit region 21 shown in Fig. 3. Below, pixels provided on the first panel 10 that have a form different from that of the unit region 21 will be described with reference to Figs. 12 to 14.

[0086] 12 is a diagram showing a first pixel PixA as an example of the shape of a pixel provided on the first panel 10. The first pixel PixA has a square shape when viewed from a plan view. One of the two diagonals of the square of the first pixel PixA extends along the second direction Dy, and the other of the two diagonals extends along the first direction Dx. The first pixel PixA includes one first sub-pixel Rpix, two second sub-pixels Gpix, one third sub-pixel Bpix, and one light-transmitting portion 250. The first sub-pixel Rpix and the third sub-pixel Bpix included in the first pixel PixA are aligned in the second direction Dy at an interval at a position overlapping one of the two diagonals of the first pixel PixA. The two second sub-pixels Gpix included in the first pixel PixA are arranged in the first direction Dx at an interval at a position closer to the first sub-pixel Rpix than the other of the two diagonals of the first pixel PixA. Similar to the above-described light-transmitting portion 25, the light-transmitting portion 250 functions as a light-transmitting region that transmits light from the second panel 30. The light-transmitting portion 250 is disposed between the first sub-pixel Rpix and one of the two second sub-pixels Gpix. The first sub-pixel Rpix, two second sub-pixels Gpix, one third sub-pixel Bpix, and one light-transmitting portion 250 included in the first pixel PixA have a square shape in a plan view, with one of the two diagonals of each square extending along the second direction Dy and the other of the two diagonals extending along the first direction Dx. Furthermore, the size of the third subpixel Bpix, as viewed from a plan view, is larger than the first subpixel Rpix, the second subpixel Gpix, and the light-transmitting portion 250. The first subpixel Rpix, the second subpixel Gpix, and the light-transmitting portion 250 are approximately the same in size as viewed from a plan view.

[0087] 13 is a diagram showing a first pixel PixB as an example of the form of a pixel provided on the first panel 10. The first pixel PixB differs from the first pixel PixA in that the first pixel PixB has two light-transmitting portions 250. One of the two light-transmitting portions 250 provided in the first pixel PixB is disposed between the first sub-pixel Rpix and one of the two second sub-pixels Gpix. The other of the two light-transmitting portions 250 is disposed between the first sub-pixel Rpix and the other of the two second sub-pixels Gpix. As described above, except for the points noted otherwise, the first pixel PixB is similar to the first pixel PixA.

[0088] 14 is a diagram showing a first pixel PixC as an example of the shape of a pixel provided on the first panel 10. The first pixel PixC has a square shape when viewed from a plan view. One of the two diagonals of the square of the first pixel PixC extends along the second direction Dy, and the other of the two diagonals extends along the first direction Dx. The first pixel PixC includes one first subpixel Rpix, one second subpixel Gpix, one third subpixel Bpix, and one light-transmitting portion 250. The light-transmitting portion 250 and the third subpixel Bpix included in the first pixel PixC are aligned in the second direction Dy at a distance from each other at a position overlapping one of the two diagonals of the first pixel PixA. The first subpixel Rpix and the second subpixel Gpix included in the first pixel PixC are aligned in the first direction Dx at a distance from each other at a position closer to the light-transmitting portion 250 than the other of the two diagonals of the first pixel PixC. The shapes and relative sizes of the first subpixel Rpix, the second subpixel Gpix, the third subpixel Bpix, and the light-transmitting portion 250 included in the first pixel PixC in plan view are similar to those of the first pixel PixA.

[0089] 12 to 14 , the light-transmitting portion 250 functioning as a light-transmitting region is provided between a plurality of sub-pixels included in pixels (first pixels PixA, PixB, and PixC) provided in the first display region 20 (see FIGS. 1 and 2 ) of the first panel 10. This allows both the display output of an image by the first panel 10 and the transmission of light from the second panel 30.

[0090] 2 and 3, in the above-described embodiment, the second pixels 41 of the second panel 30 are larger in size in a plan view than the unit regions 21 of the first panel 10, but the relationship between the pixels provided on the first panel 10 and the pixels provided on the second panel is not limited to this. Below, an example of the second panel 30A in which a relationship different from the relationship between the pixels provided on the first panel 10 and the pixels provided on the second panel 30 obtained by combining FIGS. 2 and 3 is established will be described with reference to FIG.

[0091] FIG. 15 is a schematic diagram showing the main configuration of the second panel 30A when viewed from a planar perspective. A plurality of second pixels 410 are arranged two-dimensionally in the second display region 40 of the second panel 30A shown in FIG. 15. The plurality of second pixels 410 shown in FIG. 3 are arranged in a matrix along the first direction Dx and the second direction Dy. The plurality of second pixels 410 and the plurality of unit regions 21 in the first panel 10 described with reference to FIG. 2 overlap in a 1:1 relationship when viewed from a planar perspective. That is, the number and arrangement of the second pixels 410 correspond to the unit regions 21 on a 1:1 basis.

[0092] 3 includes the first sub-pixel 41R, the second sub-pixel 41G, and the third sub-pixel 41B, the second pixel 410 may include an LED capable of outputting red (R) light, an LED capable of outputting green (G) light, and an LED capable of outputting blue (B) light. The second pixel 410 having such a configuration does not undergo the peak processing described above. It is sufficient that the RGB color division processing is performed individually for the first pixel Pix and the second pixel 410, which overlap at a 1:1 ratio.

[0093] Alternatively, the second pixel 410 may be configured with an LED capable of outputting white (W) light. In this case, grayscale conversion processing is performed instead of the peak processing described above. The grayscale conversion processing is a process for converting an RGB color image displayed and output in accordance with the second signal OP2 described above into a grayscale image. Note that any specific algorithm for the grayscale conversion processing may be used. For example, the maximum value of m, n, and p contained in the RGB color represented by the second signal OP2 before the grayscale conversion processing may be used as the gradation value after the grayscale conversion processing. Alternatively, the gradation value after the grayscale conversion processing may be derived based on a weighted average method, in which a certain weight is assigned according to each of the values ​​of m, n, and p and the average is calculated. Alternatively, the gradation value after the grayscale conversion processing may be derived using any other method generally applicable to grayscale conversion.

[0094] Although the configuration of the second panel 30A, which differs from the second panel 30, has been described above with reference to FIG. 15 , the configuration of the second panel is not limited to the second panel 30 and the second panel 30A. For example, when the size of the second pixels 41 is larger than the unit regions 21 in a planar view, the ratio between the size of the unit regions 21 and the size of the second pixels 41 is not limited to 1:9. For example, it may be 1:4, 1:16, 1:25, or 1:36, or may be a ratio between the size of the unit regions 21 and the size of the second pixels 41 not listed here. When the ratio between the size of the unit regions 21 and the size of the second pixels 41 is 1:4, the ratio between the number of unit regions 21 and the number of second pixels 41 is 4 (= 2 × 2):1. When the ratio between the size of the unit regions 21 and the size of the second pixels 41 is 1:16, the ratio between the number of unit regions 21 and the number of second pixels 41 is 16 (= 4 × 4):1. When the ratio between the size of the unit region 21 and the size of the second pixel 41 is 1:25, the ratio between the number of unit regions 21 and the number of second pixels 41 is 25 (=5×5):1. When the ratio between the size of the unit region 21 and the size of the second pixel 41 is 1:36, the ratio between the number of unit regions 21 and the number of second pixels 41 is 36 (=6×6):1.

[0095] Furthermore, in a second panel in which pixels configured with LEDs capable of outputting white (W) light are provided in the second display region 40, the pixels of the second panel may be larger in size from a planar viewpoint than the unit region 21. In this case, the ratio between the size of the unit region 21 and the size of the pixel of the second panel may be any of 1:4, 1:9, 1:16, 1:25, and 1:36, or the ratio between the size of the unit region 21 and the size of the pixel of the second panel may be any ratio not listed here.

[0096] 12 to 14, the pixels of the first panel 10 are arranged in a matrix form, tilted at 45° with respect to the first direction Dx and the second direction Dy when viewed from a plan view. In the configurations described with reference to FIGS. 12 to 14, if an element formed by a line of pixels aligned in the first direction Dx is defined as a pixel row, the pixels included in adjacent pixel rows can be said to be arranged in a staggered pattern. When the pixels of the first panel 10 shown in FIG. 12, 13, or 14 are used, the direction of arrangement of the pixels arranged on the second panel 30 may correspond to the direction of arrangement of the pixels on the first panel 10, or the direction of arrangement of the pixels arranged on the second panel 30 may be in a matrix form, regardless of the pixels on the first panel 10.

[0097] 12, 13, or 14 is used, and the pixels of the second panel 10 shown in FIG. 3 or 14 are used, and the pixels of the first panel 10 and the pixels of the second panel 30 do not strictly overlap at a ratio of k:1 (k is a natural number), it is sufficient that the pixels of the first panel 10 that correspond to one pixel of the second panel 30 are identified. In other words, it is sufficient that it is determined in advance which pixel data that forms the first signal OP1 provided to the pixel of the first panel 10 will form the second signal OP2 of which second panel 30. It is sufficient that information indicating this relationship between the first signal OP1 and the second signal OP2 is held in the image processing circuit 60 as information that can be referenced by the signal processing unit 61.

[0098] 10 has been described as an example of a gamma curve based on the PQ method, but the gamma curve corresponding to the relationship between the input and output of the display device is not limited to this. The gamma curve applied to the display device may be any gamma curve that corresponds to the dynamic range required of the display device (whether HDR is required, compliance with the required HDR standard, etc.).

[0099] Furthermore, other effects and advantages brought about by the aspects described in this embodiment that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure.

[0100] REFERENCE SIGNS LIST 1 display device 10 first panel 17 anode 18 cathode 19 light-emitting layer 20 first display area 21 unit area 25 light-transmitting portion 30 second panel 39 light-emitting element 40 second display area 41 second pixel Pix first pixel Rpix first sub-pixel Gpix second sub-pixel Bpix third sub-pixel

Claims

1. A display device comprising: a first panel which is a self-luminous image display panel; and a second panel which is a self-luminous image display panel of a different type from that of the first panel; a first display area in which an image is displayed on the first panel and a second display area in which an image is displayed on the second panel overlap; the first display area is located on the display surface side of the second display area; and the first display area is provided with a translucent area that can transmit light output from the second display area.

2. The display device according to claim 1, wherein the first panel is an OLED panel, and the second panel is an image display panel whose pixels are composed of inorganic light-emitting elements.

3. The display device according to claim 1 or 2, wherein the maximum luminance that can be output by the pixels of the second panel is higher than the maximum luminance that can be output by the pixels of the first panel.

4. The display device according to claim 1 or 2, wherein the light-transmitting region is provided between a plurality of pixels provided in the first display region.

5. The display device according to claim 1 or 2, wherein the light-transmitting region is provided between a plurality of sub-pixels included in a pixel provided in the first display region.

6. The display device according to claim 1 or 2, wherein the number of pixels per unit area of ​​the second panel is smaller than the number of pixels per unit area of ​​the first panel.

7. The display device according to claim 1 or 2, further comprising a diffusion plate disposed between the first panel and the second panel for diffusing light.

8. A display device according to claim 1 or 2, wherein the pixels of the first panel are controlled to have a predetermined luminance less than the maximum luminance that can be output as the upper limit luminance during display output, and pixels of the second panel that overlap with pixels of the first panel that are lit at the upper limit luminance are lit during display output when the luminance is insufficient with only the upper limit luminance.

9. The display device according to claim 8, wherein pixels of the second panel that overlap with pixels of the first panel that are lit at the upper limit luminance are lit at a luminance that corresponds to the difference between the luminance corresponding to the gradation value indicated by the input signal and the upper limit luminance.

Images