Light-emitting device and method for driving light-emitting device

Abstract

The number of light-emitting elements is reduced while maintaining high fineness. A light-emitting device (100) is provided with: a display unit (10) in which a plurality of pixels (12) are configured by arranging a plurality of first light-emitting elements (11A) capable of emitting light of a first emission color and a plurality of second light-emitting elements (11B) capable of emitting light of a second emission color different from the first emission color in a predetermined pattern; and a lighting control unit (50) that supplies a drive current to each of the plurality of first light-emitting elements (11A) and the plurality of second light-emitting elements (11B), and controls a light-emitting period. The second light-emitting element (11B) can control the second emission color according to the drive current, and the pixel (12) is provided with the first light-emitting element (11A) and the second light-emitting element (11B) in such a manner that light of the first emission color and light of the second emission color emit light.

Description

Technical Field

[0001] The present disclosure relates to a light-emitting device and a method for driving the light-emitting device. Background Art

[0002] Displays or surface light-emitting devices using semiconductor light-emitting elements such as LEDs and LDs are used. Here, in order to manufacture a full-color LED display, it is generally necessary to arrange at least three sub-pixels of RGB for each pixel. However, in such a structure, it is necessary to provide more than three times the number of sub-pixels as the number of pixels, so it is not suitable for high definition, and there are problems of high cost and low yield due to an increase in the number of LEDs.

[0003] In response to this, a micro LED display that enables a single LED element to emit multi-color light has been disclosed (Patent Document 1). However, when a display is composed of such multi-color light-emitting micro LEDs, the actual circuit structure and driving method have not been disclosed. For example, it is not easy in the current technology to control so that the multi-color light-emitting micro LEDs emit light in all chromaticity ranges of RGB.

[0004] On the other hand, it has been conventionally considered that three sub-pixels of RGB are required for one pixel. In order to achieve high definition, it is desirable to reduce the number of sub-pixels. However, since the luminance information is almost represented by the colors of G and R, if there are no light-emitting elements that emit light in the colors of G and R in all pixels, it will be a pixel defect. In addition, if the number of sub-pixels is reduced, there is a problem of reduced fineness.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-52168

[0008] Patent Document 2: U.S. Patent No. 10885834 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] One of the problems of the present disclosure is to provide a light-emitting device and a method for driving the light-emitting device that can maintain high definition and reduce the number of light-emitting elements when a display or the like is composed of multi-color light-emitting semiconductor light-emitting elements. Another problem is to provide a light-emitting device and a method for driving the light-emitting device in which the number of sub-pixels is reduced. In addition, the description of these problems does not prevent the existence of other problems. In addition, one aspect of the present disclosure does not need to solve all of these problems. Furthermore, based on the description of the specification, drawings, and claims of the present disclosure, other problems can be extracted.

[0011] Technical solutions for solving technical problems

[0012] The light-emitting device according to one aspect of the present disclosure includes: a display unit that forms a plurality of pixels by arranging a plurality of first light-emitting elements capable of emitting light of a first emission color and a plurality of second light-emitting elements capable of emitting light of a second emission color different from the first emission color in a predetermined pattern; and a lighting control unit that supplies drive currents to the plurality of first light-emitting elements and the plurality of second light-emitting elements respectively and controls the light-emitting period, wherein the second light-emitting element can control the second emission color according to the drive current, and the first light-emitting element and the second light-emitting element are arranged in the pixel so as to emit light of the first emission color and the second emission color.

[0013] In addition, in the driving method of the light-emitting device according to another aspect of the present disclosure, the light-emitting device includes: a display unit that forms a plurality of pixels by arranging a plurality of first light-emitting elements capable of emitting light of a first emission color and a plurality of second light-emitting elements capable of emitting light of a second emission color different from the first emission color and capable of controlling the emission color according to the drive current in a predetermined pattern; and a lighting control unit that supplies drive currents to the plurality of first light-emitting elements and the plurality of second light-emitting elements respectively and controls the light-emitting period, wherein the driving method of the light-emitting device includes the following steps: preparing the display unit in which the first light-emitting element and the second light-emitting element are arranged in each pixel so as to emit light of the first emission color and the second emission color; and the lighting control unit supplies drive currents to the plurality of first light-emitting elements and the plurality of second light-emitting elements respectively and controls the light-emitting period to perform lighting.

[0014] Advantages of the invention

[0015] According to the light-emitting device and the driving method of the light-emitting device in the above manner, by using a light-emitting element capable of controlling the emission color according to the drive current, multi-color light emission such as full color can be achieved, and the emission color is divided into sub-pixels for display, thereby suppressing a decrease in spatial fineness. Description of the drawings

[0016] Figure 1 It is a block diagram showing the light-emitting device of Embodiment 1.

[0017] Figure 2 is Figure 1 a schematic enlarged view of the display unit of

[0018] Figure 3 It is a schematic enlarged top view showing a display unit in which pixels are formed by first light-emitting elements and second light-emitting elements.

[0019] Figure 4 is shown in Figure 3Schematic enlarged top view of a state in which the emission luminance of a unit sub-pixel group changes.

[0020] Figure 5 It is a flowchart showing the steps of determining the drive current value and emission period of each sub-pixel.

[0021] Figure 6 It is a block diagram showing the display unit of the light-emitting device of Embodiment 1.

[0022] Figure 7 Is Figure 6 Schematic enlarged view of the display unit of.

[0023] Figure 8 It is a timing chart showing the lighting timings of the first light-emitting element and the second light-emitting element.

[0024] Figure 9 It is a block diagram showing an example of setting a first control circuit and a second control circuit in a pixel circuit.

[0025] Figure 10 It is a schematic cross-sectional view showing an example of the element structure of a light-emitting element.

[0026] Figure 11 It is a functional block diagram showing a method for determining the drive current value and the PWM emission period.

[0027] Figure 12A Is used to show in Figure 11 Chromaticity diagram of the steps for determining the emission chromaticity in, Figure 12B It is a chromaticity diagram showing a conventional chromaticity range.

[0028] Figure 13 It is a schematic enlarged view of the display unit of the light-emitting device of Embodiment 2.

[0029] Figure 14 Is showing Figure 13 Schematic enlarged view of the unit sub-pixel group in the display unit of.

[0030] Figure 15 It is a schematic enlarged top view of the display unit of the light-emitting device of Embodiment 3.

[0031] Figure 16 Is showing the determination of Figure 15 Flowchart of the steps for the drive current value and emission period of each sub-pixel of.

[0032] Figure 17 It is a schematic enlarged view of the display unit of the light-emitting device of Embodiment 4.

[0033] Figure 18 It is a schematic enlarged top view of the display unit of the light-emitting device of Embodiment 5.

[0034] Figure 19 is a chromaticity diagram for representing the steps of determining the emission chromaticity in a Figure 18 light-emitting device.

[0035] Figure 20 is a flowchart showing the steps of determining the drive current values and emission periods of Figure 18 each sub-pixel.

[0036] Figure 21A is a schematic diagram showing one pixel of the light-emitting device of Embodiment 1, Figure 21B is a schematic diagram showing one pixel of the light-emitting device of Embodiment 6.

[0037] Description of Reference Numerals

[0038] 100, 200, 300, 400, 500... Light-emitting devices

[0039] 2... n-type semiconductor layer

[0040] 3... Active layer

[0041] 4... p-type semiconductor layer

[0042] 5... n-side electrode

[0043] 6... p-side electrode

[0044] 8... Pixel drive circuit

[0045] 9... Power supply line

[0046] 10, 10B, 10C, 10D, 10E... Display unit

[0047] 11... Light-emitting element; 11A, 11A’... First light-emitting element

[0048] 11B, 11B1, 11B2, 11B3, 11B4... Second light-emitting element

[0049] 12, 12a, 12b, 12c, 12d, 12B, 12B1, 12B2, 12C, 12D, 12E, 12F... Pixel

[0050] 13G, 13G2, 13G3... Unit sub-pixel group

[0051] 13A... First sub-pixel

[0052] 13B, 13B1, 13B2, 13B3, 13B4... Second sub-pixel

[0053] 14... Pixel circuit; 14A... First sub-pixel circuit;

[0054] 14B, 14B1, 14B2, 14B3, 14B4... Second sub-pixel circuit

[0055] 20... Scanning section

[0056] 30... Driving section

[0057] 50, 50A, 50B, 50B1, 50B2, 50B3, 50B4... Lighting control section

[0058] 51, 51A, 51B, 51B1, 51B2, 51B3, 51B4... First control circuit

[0059] 52, 52A, 52B, 52B1, 52B2, 52B3, 52B4... Second control circuit

[0060] 60... Driving control section

[0061] 70... Information holding section

[0062] WS... Write scan line

[0063] WS1... Power control signal write scan line; WS2... Analog image signal write scan line

[0064] SL... Signal line; SL1... Power control signal line; SL2... Analog image signal line Detailed implementation mode

[0065] Hereinafter, the present disclosure will be described in more detail based on the drawings. In addition, in the following description, terms indicating specific directions and positions (for example, "upper", "lower", and other terms including these terms) are used as needed, but the use of these terms is for easy understanding of the invention with reference to the drawings, and does not limit the technical scope of the present disclosure according to the meanings of these terms. In addition, parts with the same reference numerals in multiple drawings represent the same or equivalent parts or components.

[0066] Furthermore, the following-described embodiments represent specific examples of the technical idea of the present disclosure, and the present disclosure is not limited to the following. In addition, the sizes, materials, shapes, relative configurations, etc. of the components described below are not intended to limit the scope of the present disclosure only thereto, but are intended to be illustrative as long as there is no specific description. In addition, the content described in one embodiment or example can also be applied to other embodiments or examples. In addition, the sizes or positional relationships of the components shown in the drawings are sometimes exaggerated for clear explanation.

[0067] [Embodiment 1]

[0068] Figure 1 A block diagram showing the light-emitting device 100 of Embodiment 1 Figure 2It represents an enlarged view of the display unit. The light-emitting device 100 shown in these figures includes a display unit 10, a driving unit 30, a lighting control unit 50, an information holding unit 70, a scanning unit 20, and a driving control unit 60.

[0069] (Display unit 10)

[0070] The display unit 10 arranges a plurality of first light-emitting elements 11A and a plurality of second light-emitting elements 11B in a prescribed pattern to form a plurality of pixels 12. In addition, in the present disclosure, the first light-emitting element 11A and the second light-emitting element 11B are sometimes collectively referred to as the light-emitting element 11. The plurality of first light-emitting elements 11A and the second light-emitting elements 11B are arranged in a row-column shape or a matrix shape. Figure 1 The light-emitting device 100 employs an active matrix driving method as the lighting driving method for lighting each pixel 12.

[0071] The display unit 10 arranges at least one or more of the plurality of second light-emitting elements 11B in each of the pixels 12. On the other hand, the plurality of first light-emitting elements 11A are arranged so as to straddle adjacent pixels 12. That is, in each pixel 12, one or more second light-emitting elements 11B are included. On the other hand, the first light-emitting elements 11A are arranged in such a form that a plurality of adjacent pixels share the same first light-emitting element 11A. As a result, the number of first light-emitting elements 11A is conceptually one or less per pixel 12. In Figure 3 an example, each pixel 12 is composed of one second light-emitting element 11B and a part of any one of the first light-emitting elements 11A arranged around it. As a result, the number of first light-emitting elements 11A per pixel is 1 / 4, that is, 0.25. However, it does not mean that there are physically 1 / 4 first light-emitting elements. Instead, one first light-emitting element is shared by a plurality of second light-emitting elements to form a plurality of pixels. As a result, it only means that the number of first light-emitting elements per pixel is relatively less than one in terms of calculation. Based on the display, one first light-emitting element 11A is in a state of being shared among a plurality of pixels formed by adjacent second light-emitting elements 11B. That is, since the emission color of the first light-emitting element 11A is determined between adjacent pixels, one first light-emitting element 11A does not display with 1 / 4 different emission colors or emission luminances. In addition, in Figure 3 examples such as, in the relationship of a drawing that virtually represents a pixel as a square, it may seem as if the first light-emitting element 11A is divided into four equal parts, but in actual display, one first light-emitting element 11A is only shared among a plurality of pixels formed by a single second light-emitting element 11B. For example, in the following Figure 17In this case, pixels are drawn in a rectangular shape, so that a state in which one first light-emitting element 11A is shared among three adjacent pixels is shown. In the present disclosure, "one-quarter or less" of the first light-emitting element does not mean physically dividing the first light-emitting element, but rather, as a result of sharing the first light-emitting element among a plurality of pixels, it has a conceptual meaning of being one or less in calculation. The first light-emitting element 11A and the second light-emitting element 11B that constitute one pixel 12 are called sub-pixels. Conversely, a plurality of second light-emitting elements 11B, namely, four second light-emitting elements 11B1, 11B2, 11B3, and 11B4, are arranged around each first light-emitting element 11A. Specifically, pixel 12a is composed of the first light-emitting element 11A and the second light-emitting element 11B1, pixel 12b is composed of the first light-emitting element 11A and the second light-emitting element 11B2, pixel 12c is composed of the first light-emitting element 11A and the second light-emitting element 11B3, and pixel 12d is composed of the first light-emitting element 11A and the second light-emitting element 11B4.

[0072] The first light-emitting element 11A can emit a first light color. In addition, the second light-emitting element 11B can emit a second light color different from the first light color. Each pixel 12 provided with such a first light-emitting element 11A and a second light-emitting element 11B is expressed by mixing the light of the first light color and the light of the second light color.

[0073] The first light color of the first light-emitting element 11A can be set to emit light at a fixed wavelength. On the other hand, the second light color of the second light-emitting element 11B can be variable according to its drive current. The second light-emitting element 11B whose light emission color can be controlled according to the drive current can appropriately use a multi-color light-emitting type light-emitting wavelength variable LED.

[0074] In the light-emitting device 100 of Embodiment 1, the first light color is blue light, and the second light color is variable between green light and red light. According to this structure, taking advantage of the fact that the human visual sensitivity to blue is low, it is possible to implement a display device that does not provide blue sub-pixels in all pixels, but shares them with adjacent pixels to reduce the number of required light-emitting elements and can emit light of various colors.

[0075] (Lighting control unit 50)

[0076] The lighting control unit 50 supplies drive currents to the plurality of first light-emitting elements 11A and the plurality of second light-emitting elements 11B respectively, and controls the lighting period. In Figure 2In the example shown in the enlarged view, the lighting control unit 50 is connected to the power supply line 9 extending in the horizontal direction and the write scan line WS. The lighting control unit 50 is driven by receiving power supply from the power supply line 9, and receives the timing of receiving the power control signal or the analog image signal via the write scan line WS. On the other hand, the lighting control unit 50 is also connected to the signal line SL extending in the vertical direction, and receives the power control signal or the analog image signal.

[0077] As described above, the light-emitting device 100 is composed of the first light-emitting element 11A capable of emitting the first light-emitting color and the second light-emitting element 11B capable of emitting the second light-emitting color, and the light-emitting element 11 constituting one pixel 12 makes the second light-emitting color variable, thereby suppressing the range of required color changes. Here, a driving method of the light-emitting device 100 will be described. First, a display unit 10 is prepared in which the first light-emitting element 11A and the second light-emitting element 11B are arranged so that each pixel 12 emits light of the first light-emitting color and the second light-emitting color. Next, the lighting control unit 50 supplies drive currents to the plurality of first light-emitting elements 11A and the plurality of second light-emitting elements 11B respectively, and controls the lighting period to turn them on. In this way, even if the second light-emitting element 11B capable of emitting different light-emitting colors according to the drive current is not controlled to emit light in the entire RGB range area, the light-emitting control is limited to, for example, only the light-emitting control variable in a limited wavelength area from green light to red light. Thus, multicolor light emission of each pixel 12 can be achieved in combination with the first light-emitting color of the first light-emitting element 11A, and simpler light-emitting control can be realized.

[0078] The process of the lighting control unit 50 turning on the plurality of first light-emitting elements 11A and the plurality of second light-emitting elements 11B may include the following processes: determining the chromaticity of the second light-emitting color and the brightness ratio between the first light-emitting element 11A and the second light-emitting element 11B in a manner corresponding to the first light-emitting color according to the chromaticity signal and the brightness signal to be displayed by the pixel 12; determining the light-emitting intensity corresponding to the brightness signal to be displayed based on the chromaticity of the second light-emitting color and the brightness ratio; the first control circuit 51 of the lighting control unit 50 refers to the information holding unit 70 to supply drive current values corresponding to their respective light-emitting colors to the first light-emitting element 11A and the second light-emitting element 11B; the second control circuit 52 of the lighting control unit 50 controls the lighting period of the drive current value supplied by the first control circuit 51 according to the determined light-emitting intensity.

[0079] In addition, the step of the lighting control unit 50 lighting the plurality of first light-emitting elements 11A and the plurality of second light-emitting elements 11B may also include the following steps: In the first light-emitting element 11A, the second control circuit 52 controls the light-emitting intensity by PWM control in a state where the drive current of the plurality of first light-emitting elements 11A is constant; In the second light-emitting element 11B, the first control circuit 51 controls the light-emitting color according to the current value for driving the plurality of second light-emitting elements 11B; The second control circuit 52 controls the brightness according to the light-emitting period of the current value of the plurality of second light-emitting elements 11B controlled by the first control circuit 51. Here, the state where the drive current of the first light-emitting element 11A is constant is preferably the drive current value under the drive condition with the maximum luminous efficiency.

[0080] The lighting control unit 50 preferably sets the time width of supplying current to the light-emitting element 11 based on the result of comparing a first signal including a triangular wave signal and a first DC voltage set in a prescribed period. In addition, it is preferable to control the current value supplied to the lighting control unit 50 based on a second DC voltage set in a period different from the prescribed period. The details of the operation of the lighting control unit 50 will be described later.

[0081] (Pixel 12)

[0082] Each pixel 12 is composed of a first light-emitting element 11A and a second light-emitting element 11B. Each pixel 12 is configured to emit light of a first light-emitting color emitted by at least one or more first light-emitting elements 11A and light of a second light-emitting color emitted by at least one or more second light-emitting elements 11B.

[0083] In addition, the display unit 10 disposes the second light-emitting element 11B inside the quadrilateral that divides each pixel 12, and disposes the first light-emitting element 11A at at least any one of the corners of the quadrilateral that divides each pixel 12. Conversely, if captured with the first light-emitting element 11A as the center, it can also be considered that it is surrounded by a plurality of second light-emitting elements 11B1, 11B2, 11B3, 11B4. In the light-emitting device 100 of Embodiment 1, as Figure 3 shown by the region surrounded by the dotted line in, one pixel 12 is defined. That is, it is defined that approximately 1 / 4 of the first light-emitting element 11A exists at any one corner of the pixel 12 of the quadrilateral with each second light-emitting element 11B as the center. As a result, the first light-emitting element 11A in one pixel 12 is approximately 1 / 4. In addition, in Figure 3In the example, a structure is shown in which the first light-emitting element 11A is disposed at any corner of the quadrilateral dividing each pixel 12. However, the present disclosure is not limited to such a configuration. The first light-emitting element may be disposed so as to straddle a plurality of adjacent pixels. Therefore, the arrangement position of the first light-emitting element may also be a portion other than the corner portion, for example, the middle of the side of a rectangle. In addition, the pixel may be a polygon such as a triangle or a hexagon, or a circle. In this case, the arrangement position of the first light-emitting element may be a corner portion or a portion other than the corner portion, for example, the center of a side.

[0084] Thus, in Figure 3 In the example shown, with respect to the second light-emitting elements 11B arranged in a matrix, for each of the four second light-emitting elements 11B1, 11B2, 11B3, and 11B4, the first light-emitting element 11A is arranged in the region surrounded by these four second light-emitting elements 11B1, 11B2, 11B3, and 11B4. Then, one pixel 12 is set as a quadrilateral surrounding each second light-emitting element 11B. As a result, the first light-emitting element 11A is located at any of the corners of the quadrilateral. By placing the first light-emitting element 11A at four portions adjacent to the quadrilateral surrounding each second light-emitting element 11B, approximately 1 / 4 of the first light-emitting elements 11A placed at the adjacent portions of the four pixels 12a, 12b, 12c, and 12d is allocated to one pixel 12. That is, in each pixel 12, there is one second light-emitting element 11B and approximately 0.25 first light-emitting elements 11A, and the number of first light-emitting elements 11A, that is, the number of sub-pixels, constituting one pixel 12 can be reduced. In addition, in the present disclosure, the number of the first light-emitting elements or the second light-emitting elements per pixel is not limited to this example. For example, the first light-emitting element may be 1 / 2 or 1 / 3 per pixel (detailed examples will be described later).

[0085] Thus, by relatively reducing the number of light-emitting elements constituting one pixel, simplification of the light-emitting device can be achieved. In addition, the number of pixels can be increased to achieve high definition. In particular, in the past, in order to achieve full-color display, three sub-pixels of RGB were required for one pixel. Therefore, there is a limit to high definition in a display portion with a limited area. In addition, since the luminance information is almost represented by the colors of G and R, if there are no G light-emitting elements and R light-emitting elements in all pixels, it becomes a pixel defect, and there is also a problem of reducing the fineness.

[0086] In contrast, in the present embodiment, the number of sub-pixels is reduced by taking into account the difference in visual sensitivity of the human eye to each of the RGB emission colors. Specifically, the human eye has a lower spatial resolution for blue light compared to green light or red light, and thus has the characteristic of not perceiving a decrease in fineness. In particular, blue light only carries color information, and the visual sensitivity of the human eye to the color information of blue light is low. Therefore, even if there is no light-emitting element for blue light in all pixels, a person cannot notice. Utilizing this property, one or more second light-emitting elements 11B that emit green light or red light are arranged in each pixel 12, and the first light-emitting element 11A that emits blue light is arranged so as to straddle adjacent pixels 12, thereby enabling the reduction of the number of sub-pixels constituting each pixel 12.

[0087] (Unit sub-pixel group 13G)

[0088] That is, in the display unit 10, sub-pixel groups in which the second light-emitting element 11B or the first light-emitting element 11A constituting the sub-pixels are arranged adjacent to each other in a predetermined pattern are periodically arranged, and in such repeatedly arranged sub-pixel groups (hereinafter referred to as "unit sub-pixel groups 13G"), the first light-emitting element 11A is arranged so as to straddle the pixels 12 constituted by the sub-pixel groups. In other words, the unit sub-pixel group 13G is a repeating unit of the first light-emitting element 11A and the second light-emitting element 11B, which are the sub-pixels constituting the display unit 10 and include one first light-emitting element 11A as a sub-pixel. Here, if the relationship between the pixel and the light-emitting element is sorted in ascending order of concept, then in the Figure 2 example shown, the sub-pixel is composed of a first light-emitting element and a second light-emitting element. In addition, the pixel is composed of a first light-emitting element and one second light-emitting element. On the other hand, the sub-pixel group is composed of a first light-emitting element and a plurality of second light-emitting elements. In Figure 3 , the unit sub-pixel group 13G is surrounded by a solid line. This unit sub-pixel group 13G has one first light-emitting element 11A arranged at the intersection of four pixels 12a, 12b, 12c, and 12d that respectively include the second light-emitting elements 11B arranged in a matrix. In this unit sub-pixel group 13G, there are four second light-emitting elements 11B (11B1, 11B2, 11B3, 11B4) and one first light-emitting element 11A, so the total number of sub-pixels is five. In addition, the present disclosure is not limited to this structure, and one first light-emitting element may be arranged for every three second light-emitting elements or every two second light-emitting elements. That is, the unit sub-pixel group may have four sub-pixels or three sub-pixels in addition to having five sub-pixels as shown in Figure 3 .

[0089] In addition, by using the same structure in the first light-emitting element that emits blue light as the second light-emitting element which is a variable light-emitting element, that is, by making both the first light-emitting element 11A and the second light-emitting element 11B variable light-emitting elements, it is possible to simplify the manufacturing process by using common light-emitting elements. Or, by using a conventional fixed-wavelength light-emitting element, i.e., a blue monochromatic light-emitting element, in the first light-emitting element, the second light-emitting element can use a G-R variable light-emitting element that limits the variable range of the emission wavelength to G-R, thereby improving the yield rate during the manufacture of the second light-emitting element. This is because the manufacturing process of the G-R variable light-emitting element is likely to be simpler than that of the B-G-R variable light-emitting element.

[0090] The spatial position of the luminance points in the pixel 12 is determined by the second light-emitting element 11B. Therefore, the second light-emitting elements 11B are preferably arranged evenly in a square or triangular shape, etc. On the other hand, the main purpose of the first light-emitting element 11A is to provide the chromaticity of each unit sub-pixel group 13G. Therefore, visually, it is ideal for the arrangement position of the first light-emitting element 11A to be equidistant from all the second light-emitting elements within the unit sub-pixel group, but it does not necessarily need to be arranged equidistant from the surrounding second light-emitting elements 11B, as long as it is within the vicinity area of the pixel group.

[0091] Figure 3 An example of such a unit sub-pixel group 13G is shown. In this display unit 10, the sub-pixels constituting one pixel 12 are composed of the sub-pixels of one second light-emitting element 11B and 1 / 4 of the sub-pixels of the first light-emitting element 11A. In this case, the unit sub-pixel group 13G is surrounded by a solid line to form 4 pixels. In this way, the first light-emitting element 11A is arranged at the boundary of 4 square pixels 12 and emits blue light. Therefore, the emission colors of the 4 pixels respectively constituted by the 4 second light-emitting elements 11B1, 11B2, 11B3, 11B4 surrounding this first light-emitting element 11A, that is, each second light-emitting element 11B belonging to the unit sub-pixel group 13G Figure 3 become the same color as shown. On the other hand, as Figure 4 shown, the emission luminance of each second light-emitting element 11B1, 11B2, 11B3, 11B4 is different for each pixel 12. In Figure 4 , the sub-pixels arranged to surround each first light-emitting element 11A, that is, the second light-emitting elements 11B1, 11B2, 11B3, 11B4 ( Figure 4 the unit sub-pixel group 13G in the area shown by the solid line in Figure 4 ) have the same chromaticity but different luminances. In

[0092] (Step of determining emission color)

[0093] Here, as a step of determining the emission color and emission luminance of each sub-pixel constituting the unit sub-pixel group 13G, first, the emission color of the unit sub-pixel group 13G is determined. If the emission color of the unit sub-pixel group 13G is determined, the emission color of one first light-emitting element 11A constituting the unit sub-pixel group 13G is pre-determined, and thus the emission colors of the four second light-emitting elements 11B1, 11B2, 11B3, and 11B4 are determined. That is, the emission colors of these four second light-emitting elements 11B1, 11B2, 11B3, and 11B4 are the same as described above. Next, the emission luminance of each sub-pixel is determined.

[0094] Here, based on Figure 5 the flowchart of, the step of determining the drive current value and emission period of each sub-pixel is described. First, as step S501, for each unit sub-pixel group 13G, the average chromaticity and average luminance in the image data (moving image or still image) to be displayed are determined. In Figure 3 the example of, for a total of five light-emitting elements 11 including the first light-emitting element 11A and the four second light-emitting elements 11B1, 11B2, 11B3, and 11B4 surrounding the first light-emitting element 11A, which constitute the five sub-pixels of the unit sub-pixel group 13G, the average chromaticity and average luminance are calculated for each unit sub-pixel group 13G. In addition, in this structure, although the fineness of the chromaticity is reduced to 1 / 4, since the color resolution of the human eye is lower than the resolution of the luminance, the deterioration of the image quality is not perceived.

[0095] Next, as step S502, the average chromaticity and average luminance of the second light-emitting elements 11B1, 11B2, 11B3, and 11B4 in the unit sub-pixel group 13G, and the chromaticity and luminance of the first light-emitting element 11A are determined respectively using a prescribed algorithm. In addition, the chromaticity of the first light-emitting element 11A is determined by the drive current value, and the luminance is determined by the emission period. Further, the second light-emitting elements 11B1, 11B2, 11B3, and 11B4 in the unit sub-pixel group 13G emit light with the same chromaticity as the same drive current value. In Figure 3 the example of, the second light-emitting elements 11B1, 11B2, 11B3, and 11B4 of the four sub-pixels have the same emission color. In addition, the prescribed algorithm for respectively determining the average chromaticity and average luminance of the second light-emitting element 11B and the chromaticity and luminance of the first light-emitting element 11A is referred to Figure 11 described later.

[0096] Finally, as step S503, the brightness of each sub-pixel belonging to the unit sub-pixel group 13G is determined. That is, based on the brightness of each sub-pixel belonging to the unit sub-pixel group 13G, the brightness of the second light-emitting element 11B is allocated, and the brightness of each sub-pixel is determined. The brightness of the second light-emitting element 11B is determined by the light-emitting period. Here, based on the ratio of the brightness signals of the 4 sub-pixels of the second light-emitting element 11B that make up the unit sub-pixel group 13G, the light-emitting period of the second light-emitting element 11B is allocated, and the light-emitting period of each pixel 12 is determined. As described above, the brightness of each pixel 12 can be determined after the chromaticity of each unit sub-pixel group 13G has been determined.

[0097] (First light-emitting element 11A and second light-emitting element 11B)

[0098] The first light-emitting element 11A and the second light-emitting element 11B can preferably use semiconductor light-emitting elements such as light-emitting diodes (LEDs) or semiconductor lasers (LDs). For the LED, a structure in which one or more semiconductor laminates having a light-emitting portion (hereinafter, also simply referred to as "semiconductor laminate") are arranged can be used. The semiconductor laminate has light-emitting characteristics. Such a semiconductor laminate uses a structure in which multiple semiconductor layers such as ZnS, SiC, GaN, GaP, InN, AlN, ZnSe, GaAsP, GaAlAs, InGaN, GaAlN, AlInGaP, and AlInGaN are laminated on a substrate by a liquid phase growth method, an HVPE method, or an MOCVD method, and an active layer is formed on any one of the semiconductor layers. By selecting the material of the semiconductor layer and its mixed crystal ratio, the emission wavelength from the active layer can be variously selected from ultraviolet light to infrared light. In particular, when it is a display device that can be appropriately used outdoors, a semiconductor laminate capable of high-brightness emission is required. Therefore, as the material of the light-emitting portion for high-brightness emission, a nitride semiconductor is preferably selected. For example, as the material of the light-emitting portion, In X Al Y Ga 1-X-Y N (0 ≤ X ≤ 1, 0 ≤ Y ≤ 1, X + Y ≤ 1), etc.

[0099] In Embodiment 1, as each of the first light-emitting elements 11A and the second light-emitting elements 11B, semiconductor light-emitting elements such as light-emitting diodes or semiconductor lasers are used. In addition, a micro LED can also be used as the light-emitting diode. Considering the chip size of 5 μm to 100 μm and the luminous efficiency, the micro LED is preferably 10 μm to 50 μm.

[0100] The first light-emitting element 11A fixes the first light-emitting color as its light-emitting color. On the other hand, the second light-emitting element 11B makes the second light-emitting color variable. The second light-emitting element 11B emits different light-emitting colors according to the drive current. For example, when driven with a first drive current, it emits light of a first light-emitting wavelength, such as red, and when driven with a second drive current larger than the first drive current, it emits light of a second light-emitting wavelength shorter than the first light-emitting wavelength, such as green.

[0101] Each of the first light-emitting elements 11A and the second light-emitting elements 11B is connected to a plurality of write scan lines WS and a plurality of signal lines SL. By connecting the first light-emitting element 11A and the second light-emitting element 11B to one of the plurality of write scan lines WS and one of the plurality of signal lines SL respectively and arranging them in a row and column pattern, the display unit 10 is constituted.

[0102] (Scanning unit 20)

[0103] The scanning unit 20 is provided in a column further to the left of the leftmost column of the pixels 12 arranged in a matrix. The scanning unit 20 may also be provided in a column further to the right of the rightmost column of the pixels 12 arranged in a matrix. In addition, as Figure 6 , Figure 7 shown, from the scanning unit 20 as the write scan line WS, a power control signal write scan line WS1 and an analog image signal write scan line WS2 are provided for each row of the pixels 12. The power control signal write scan line WS1 and the analog image signal write scan line WS2 extend in the row direction.

[0104] When the power control signal write scan line WS1 writes the drive current value that determines the light-emitting color as a voltage value through the power control signal, it supplies the digital signal, that is, the first scan signal, for selecting the pixel circuit 14 ( Figure 1 the lighting control unit 50 + the light-emitting element 11) in the row direction. When the analog image signal write scan line WS2 writes the light-emitting period determined by the light-emitting gray scale as a voltage value through the analog image signal, it supplies the digital signal, that is, the second scan signal, for selecting the pixel circuit 14 in the row direction.

[0105] (Drive unit 30)

[0106] As Figure 6 , Figure 7As shown, for each column of each pixel 12, the driving unit 30 causes the power control signal line SL1 and the analog image signal line SL2 to extend in the vertical direction as the signal line SL. The driving unit 30 supplies a power control signal to each pixel circuit 14 via the power control signal line SL1. The power control signal is an analog signal capable of obtaining multiple voltage values. The driving unit 30 supplies an analog image signal to each pixel circuit 14 via the analog image signal line SL2. The analog image signal is also an analog signal capable of obtaining multiple voltage values. Each pixel circuit 14 that is supplied with the power control signal and has a voltage value written therein sets a driving current based on the written voltage value. Each pixel circuit 14 that is supplied with the analog image signal and has a voltage value written therein sets a threshold voltage for comparison with a reference triangular wave signal based on the voltage value of the analog image signal, and sets the time width during which the pixel circuit 14 emits light. During the light emission period, a reference triangular wave signal (not shown) is supplied to the pixel circuit 14, and the light emitting element 11 of each pixel circuit 14 emits light during the on period based on the voltage of the written analog image signal. In addition, the driving current value when the light emitting element 11 emits light is set by the voltage of the power control signal (for details, refer to and cite U.S. Patent No. 10,885,834 of Patent Document 2).

[0107] In addition, the driving unit 30 may generate a reference triangular wave signal supplied to each pixel circuit 14 for each column. Alternatively, the reference triangular wave signal may be separately provided as a reference triangular wave circuit in a row lower than the lowermost row of the matrix of the pixel circuits 14. The driving unit 30 or the reference triangular wave circuit distributes the reference triangular wave supplied from the outside of these circuits to each column of the pixel circuits 14, for example.

[0108] The driving unit 30 may also include a storage unit. The storage unit can store chromaticity settings for multiple voltage values taken by the power control signal and luminance settings for multiple voltage values taken by the analog image signal. The relationship between these voltage values and the luminance settings can be adjusted and set by visually confirming the luminance of the light emitting element 11 constituting the pixel circuit 14, etc. By appropriately setting the relationship between the voltage values and the luminance settings, gamma correction can be performed. One of the advantageous points of this method is that, in the commonly known digital PWM method, the gray scale characteristic is linear, whereas gamma correction can be applied to the signal. The storage unit is formed of an electrically rewritable storage circuit, etc., for example.

[0109] (Pixel Circuit 14)

[0110] In addition, the pixel circuit 14 may be provided for each sub-pixel constituting one pixel 12. Figure 2In the example, the pixel circuit 14 includes a first sub-pixel circuit 14A and a second sub-pixel circuit 14B. The first sub-pixel circuit 14A drives a first light-emitting element 11A that constitutes the first sub-pixel 13A. On the other hand, the second sub-pixel circuit 14B drives a second light-emitting element 11B that constitutes the second sub-pixel 13B. In Figure 2 the example, as the first sub-pixel 13A, the first light-emitting element 11A emits blue light, and as the second sub-pixel 13B, the second light-emitting element 11B emits light of green to red. A pixel 12 is constituted by these first sub-pixels 13A and second sub-pixels 13B. In Figure 2 the example, the second sub-pixel 13B is constituted by a plurality of second sub-pixels 13B1, 13B2, 13B3, and 13B4. In addition, the second sub-pixel circuit 14B includes a plurality of second sub-pixel circuits. Specifically, it includes a second sub-pixel circuit 14B1, a second sub-pixel circuit 14B2, a second sub-pixel circuit 14B3, and a second sub-pixel circuit 14B4.

[0111] (Information holding unit 70)

[0112] As described above, the second light-emitting element 11B is a multi-color light-emitting type light-emitting wavelength variable LED, and its second emission color changes according to the drive current. Therefore, it is necessary to determine the drive current value for driving the second light-emitting element 11B according to the second emission color for which the second light-emitting element 11B is desired to emit light. Therefore, current-chromaticity information indicating the correspondence between the emission color for which the second light-emitting element 11B is determined to emit light and the drive current value for emitting light of that color is held in the information holding unit 70. The drive control unit 60 refers to the information holding unit 70 to determine the drive current of the second light-emitting element 11B corresponding to the second emission color. The information holding unit 70 can include, for example, a storage element such as a current-chromaticity data memory for holding the current-chromaticity data of the second light-emitting element 11B.

[0113] In addition, in addition to holding the current-chromaticity information based on the measured values of the respective second light-emitting elements 11B arranged in the display unit 10, the information holding unit 70 can also hold the current-chromaticity information generated by measuring the drive current and emission color of a light-emitting element equivalent to each of the second light-emitting elements arranged in the display unit. Alternatively, the information holding unit can also hold the current-chromaticity information determined statistically for the relationship between the drive current and emission color of the second light-emitting element and recorded. In Figure 1 the example, the information holding unit 70 has a (G-R) emission chromaticity-drive current-brightness characteristic table. In addition, here (G-R) refers to the wavelength region from green light to red light.

[0114] (Drive control unit 60)

[0115] Furthermore, the drive control unit 60 controls the operations of these scanning units 20 and drive units 30. In addition, the scanning unit 20 and the drive unit 30 control the lighting control units 50 of the respective pixels 12. As Figure 9 shown, each lighting control unit 50 can include a first control circuit 51 and a second control circuit 52. The first control circuit 51 supplies drive currents to the first light-emitting element 11A and the second light-emitting element 11B, respectively. In addition, the second control circuit 52 controls the light-emitting periods of the first light-emitting element 11A and the second light-emitting element 11B, respectively. Sometimes, the structure in which the light-emitting element 11 is connected to the lighting control unit 50 is referred to as a "pixel circuit 14". The first control circuit 51 is connected between the power supply line and the second control circuit 52. It is preferable to provide at least one or more of these first control circuits 51 and second control circuits 52 for each pixel 12.

[0116] The drive control unit 60 controls the drive unit 30 to supply drive currents to the respective first light-emitting elements 11A and second light-emitting elements 11B so that the first light-emitting elements 11A and second light-emitting elements 11B emit light with predetermined emission colors and emission brightnesses, respectively. Regarding the first light-emitting element 11A, since its first emission color is fixed, the drive control unit 60 is controlled so as to become a predetermined drive current. On the other hand, regarding the second light-emitting element 11B, the drive control unit 60 determines the drive current value for driving each second light-emitting element 11B and the on-period for causing each second light-emitting element 11B to emit light, referring to the current-chromaticity information held in the information holding unit 70, based on the predetermined emission color and gradation information of each of the second light-emitting elements 11B, and performs lighting drive on each second light-emitting element 11B with the drive current from the lighting control unit 50.

[0117] In addition, the drive control unit 60 performs gradation control of the emission brightness. For example, based on the predetermined emission color of each of the first light-emitting elements 11A and second light-emitting elements 11B, referring to the current-chromaticity information, the drive current values of the respective first light-emitting elements 11A and second light-emitting elements 11B are determined, and based on the determined drive current values and the predetermined gradation information of each of the first light-emitting elements 11A and second light-emitting elements 11B, the on-periods of the respective first light-emitting elements 11A and second light-emitting elements 11B are determined.

[0118] The drive control unit 60 may also include a storage unit in the same manner as the above-described drive unit 30. In the storage unit, it is possible to store chromaticity settings for a plurality of voltage values taken with respect to the power control signal and luminance settings for a plurality of voltage values taken with respect to the analog image signal. The relationship between these voltage values and the luminance settings can be adjusted and set by visually confirming the luminance of the light-emitting element 11 constituting the pixel circuit 14, etc. By appropriately setting the relationship between the voltage values and the luminance settings, gamma correction can be performed. One of the advantageous points of this method is that in the digital PWM method, the gray-scale characteristics are linear, whereas gamma correction can be applied to the signal. The storage unit is formed, for example, by an electrically rewritable storage circuit or the like.

[0119] In addition, the drive control unit 60 may perform lighting control on the first light-emitting elements 11A and the second light-emitting elements 11B simultaneously by the drive unit 30 in a state where the on-time information for one frame amount of each of the first light-emitting elements 11A and the second light-emitting elements 11B constituting the display unit 10 is written in the storage unit.

[0120] The drive control unit 60 determines the drive current value for driving each first light-emitting element 11A and the light-emitting period for causing each first light-emitting element 11A to emit light based on the light-emitting color information and gray-scale information of the display image provided from the outside. In addition, with reference to the current-chromaticity information held by the information holding unit 70, it determines the drive current value for driving each second light-emitting element 11B and the light-emitting period for causing each second light-emitting element 11B to emit light. Then, the drive control unit 60 performs lighting drive on each of the first light-emitting elements 11A and the second light-emitting elements 11B via the drive unit 30 using the lighting control unit 50. With such a configuration, it is possible to achieve lighting control of the display unit 10 constituted by the first light-emitting elements 11A having a fixed wavelength and the multi-color light-emitting second light-emitting elements 11B.

[0121] Regarding the second light-emitting color of the second light-emitting element 11B, if the drive current values for emitting light of each light-emitting color, red (R), green (G), and blue (B), are set as IR, IG, and IB, respectively, the magnitudes of the drive current values are IR < IG < IB. Therefore, if the light-emitting periods for the maximum gray scale of each color are set as TR, TG, and TB, the length relationship of the maximum light-emitting periods of each color during white display corresponding to full lighting is TR > TG > TB.

[0122] However, when the second emission color is made variable over the entire range of R, G, and B, the range of variation of the drive current of the second light-emitting element 11B becomes large, and its control becomes complicated. Therefore, by making the first emission color different from the second emission color and having the first light-emitting element 11A assume the first emission color, the range of the second emission color assumed by the second light-emitting element 11B can be restricted, simplifying the control. As the assignment of the first emission color and the second emission color, it is preferable to make the first emission color blue and the second emission color variable from green to red, or to make the second emission color from blue to green and the first emission color red, in such a way that the second emission color changes continuously. Among the drive current values of the multi-color light-emitting type LED, the drive current value (IB) for blue emission is the largest. Therefore, it is more preferable to make the first emission color blue and the second emission color green to red, as this can suppress the drive current value of the second light-emitting element 11B.

[0123] Therefore, in the light-emitting device 100 of Embodiment 1, the first light-emitting element 11A emits blue light of the first emission color, and the second light-emitting element 11B emits light of any color from red to green (G-R) of the second emission color. Thereby, it is possible to improve the brightness resolution without reducing the spatial color resolution, and full-color emission can be achieved by the first light-emitting element 11A and the second light-emitting element 11B. PWM can be used for the gray-scale control of each emission color. Here, the product of the maximum emission period based on PWM drive and the drive current value is R > G > B. This is because the light-emitting luminance efficiency of the second light-emitting element 11B increases in the order of R < G < B.

[0124] (Timing chart)

[0125] In Figure 2 the light-emitting device 100, in Figure 8 the timing chart shown, the lighting timings of each color are shown in the case where variable light-emitting elements of the same structure are used for the first light-emitting element 11A and the second light-emitting element 11B. In this figure, the vertical axis represents the drive current values supplied to the first light-emitting element 11A and the second light-emitting element 11B respectively, and the horizontal axis represents the energization period. Also, here, one frame period FT of the image displayed by the light-emitting device 100 is divided into a period FTa for sequentially writing image information to each pixel and a light-emitting period FTb of the pixel section. In the light-emitting period FTb of the pixel section, the first light-emitting element 11A, which is a variable light-emitting element, is fixed at a certain drive current value IB to emit a certain emission color (here, blue light). On the other hand, by controlling the energization time (i.e., the light-emitting period TB) of the drive current value IB supplied to the first light-emitting element 11A, PWM control for adjusting the light-emitting brightness, i.e., the gray scale, is performed. In Figure 8Among them, TBmax represents the maximum emission period of blue light, and a thick line represents the drive current value when the first light-emitting element 11A is lit for the maximum emission period TBmax of blue light. By PWM control, the on-time period in the maximum emission period TBmax is adjusted, thereby expressing grayscale.

[0126] On the other hand, during the emission period FTb of the pixel portion, the second light-emitting element 11B also emits light simultaneously with the first light-emitting element 11A. Since the second light-emitting element 11B can change from green light to red light, within the range from the drive current value IG corresponding to green light, for example, 515 nm, to the drive current value IR corresponding to red light, for example, 630 nm, a drive current value I(G-R) that can be varied is applied to the second light-emitting element 11B. In other words, the second light-emitting element 11B emits light with Figure 8 the vertical axis (drive current) for controlling the emission color. In addition, PWM control is performed by controlling the on-time period (i.e., the emission period T(G-R)) of the drive current value I(G-R) applied to the second light-emitting element 11B. In Figure 8 Among them, TGmax represents the maximum emission period of green light, TRmax represents the maximum emission period of red light, and a dotted line represents the drive current value when the second light-emitting element 11B is lit for the maximum emission period TGmax of green light, and a thin line represents the drive current value when it is lit for the maximum emission period TRmax of red light. As described above, IR < IG < IB on the vertical axis, and TBmax < TGmax < TRmax on the horizontal axis. In addition, an example in which the first light-emitting element 11A is set as a variable light-emitting element has been described above, but as described above, the first light-emitting element 11A can also be set as a fixed-wavelength light-emitting element. In this case, the drive current value IB is not necessarily larger than IG.

[0127] In addition, in the above description, it has been described on the assumption that the second emission color of the second light-emitting element 11B can be varied over the entire region of R, G, and B. However, by manufacturing the second light-emitting element 11B in such a way that its second emission color can be varied only within the range from R to G, advantages such as simplification of the manufacturing process and cost reduction can be obtained. For example, the manufacturing process margin of the second light-emitting element 11B can be further expanded.

[0128] In the lighting control for each frame performed by the driving unit 30, a current value corresponding to blue light, for example, 470 nm, is applied to the first light-emitting element 11A that emits blue light. In addition, in order to enable the second light-emitting element 11B to change from green light to red light, a drive current is applied to the second light-emitting element 11B within the range from a current value corresponding to green light, for example, 515 nm, to a current value corresponding to red light, for example, 630 nm. That is, the maximum current value for emitting blue light is applied to the first light-emitting element 11A, and a drive current corresponding to the second light-emitting color to be emitted is applied to the second light-emitting element 11B. In other words, the second light-emitting element 11B controls the emission color with the drive current.

[0129] In addition, a pixel signal writing period is set in each frame, and PWM control is performed after the pixel signal writing period. During the pixel signal writing period, pixel signals for one screen amount of the first light-emitting element 11A and the second light-emitting element 11B are written into the pixel memory. The driving unit 30 controls the lighting of the light-emitting element 11 with reference to the pixel signals written into the pixel memory. The pixel memory is provided in the lighting control unit 50 of the pixel circuit 14.

[0130] As Figure 9 shown, the lighting control unit 50 includes a first control circuit 51 and a second control circuit 52. The first control circuit 51 performs current driving according to the emission color. In addition, the second control circuit 52 performs PWM control. Specifically, when performing PWM control, the second control circuit 52 sets the time width of the current supplied to the light-emitting element 11 based on the result of comparing a first signal including a triangular wave signal and a first DC voltage that is an analog image signal set during a specified period. In addition, the first control circuit 51 controls the current value supplied by the lighting control unit 50 based on a second DC voltage that is a power supply control signal set during a period different from the specified period.

[0131] In addition, as Figure 6 , Figure 7 shown, the power supply control signal writing scan line WS1 and the analog image signal writing scan line WS2 extend from the scanning unit 20 and are connected to each pixel 12. In addition, the power supply control signal line SL1 and the analog image signal line SL2 extend from the driving unit 30 and are connected to each pixel 12. The driving unit 30 is a driver IC that processes the power supply control signal and the analog image signal. The power supply control signal writing scan line WS1 and the analog image signal writing scan line WS2 are connected to the pixel circuit 14 that is a TFT circuit provided on the mounting substrate. The TFT is made of low-temperature polysilicon or oxide semiconductor.

[0132] As Figure 2 and Figure 7As shown in the enlarged view of the main part, each pixel 12 is composed of a plurality of sub-pixels. Here, the pixel 12 is composed of five sub-pixels: a first sub-pixel 13A and second sub-pixels 13B1, 13B2, 13B3, and 13B4. Each sub-pixel is composed of a light-emitting element 11. In addition, the lighting control unit 50 is connected to the light-emitting element 11. As described above, by defining the pixel circuit as the lighting control unit + the light-emitting element, the sub-pixel circuit will be specifically described below as the lighting control unit + (the light-emitting element constituting the sub-pixel). The first sub-pixel circuit 14A includes a first lighting control unit 50A and a first light-emitting element 11A constituting the first sub-pixel 13A. In addition, the second sub-pixel circuit 14B includes a second lighting control unit 50B and a second light-emitting element 11B constituting the second sub-pixel 13B. Specifically, the second sub-pixel circuit 14B1 includes a second lighting control unit 50B1 and a second light-emitting element 11B1 constituting the second sub-pixel 13B1. In addition, the second sub-pixel circuit 14B2 includes a second lighting control unit 50B2 and a second light-emitting element 11B2 constituting the second sub-pixel 13B2. Moreover, the second sub-pixel circuit 14B3 includes a second lighting control unit 50B3 and a second light-emitting element 11B3 constituting the second sub-pixel 13B3. In addition, the second sub-pixel circuit 14B4 includes a second lighting control unit 50B4 and a second light-emitting element 11B4 constituting the second sub-pixel 13B4.

[0133] Each pixel circuit 14 includes a lighting control unit 50. Here, the first lighting control unit 50A includes a first control circuit 51A and a second control circuit 52A. In addition, the second lighting control unit 50B includes a first control circuit 51B and a second control circuit 52B. Specifically, the pixel circuit 14 includes a first sub-pixel circuit 14A and a second sub-pixel circuit 14B, and the second sub-pixel circuit 14B includes second sub-pixel circuits 14B1, 14B2, 14B3, and 14B4. Among them, in the first sub-pixel circuit 14A, as described above, the first lighting control unit 50A includes a first control circuit 51A and a second control circuit 52A. On the other hand, in the second sub-pixel circuit 14B, the second lighting control unit 50B1 includes a first control circuit 51B1 and a second control circuit 52B1. In addition, in the second sub-pixel circuit 14B2, the second lighting control unit 50B2 includes a first control circuit 51B2 and a second control circuit 52B2. And, in the second sub-pixel circuit 14B3, the second lighting control unit 50B3 includes a first control circuit 51B3 and a second control circuit 52B3. In addition, in the second sub-pixel circuit 14B4, the second lighting control unit 50B4 includes a first control circuit 51B4 and a second control circuit 52B4.

[0134] These first control circuits 51A and 51B supply drive currents to the first light-emitting element 11A and the second light-emitting element 11B, respectively. On the other hand, the second control circuits 52A and 52B control the light-emitting periods of the first light-emitting element 11A and the second light-emitting element 11B, respectively. Here, the first control circuits 51A and 51B are constituted by power supply control circuits, and the second control circuits 52A and 52B are constituted by analog image PWM circuits. The first control circuits (power supply control circuits) 51A and 51B are connected to the power supply line 9 and the power supply control signal line SL1. In addition, a power supply control signal writing timing is input from the power supply control signal writing scan line WS1. On the other hand, the second control circuits (analog image PWM circuits) 52A and 52B are connected in series with the power supply line 9 via the first control circuits 51A and 51B, respectively. In addition, the second control circuits 52A and 52B are also connected to the analog image signal line SL2. In addition, an analog image signal writing timing is input from the analog image signal writing scan line WS2. In this way, the light-emitting element 11 is connected to the power supply line 9 via the power supply control circuit and the analog image PWM circuit, respectively. Moreover, the drive current value is controlled by the power supply control circuit, and the drive time is controlled by the analog image PWM circuit.

[0135] In addition, in Figure 7 the example, an example in which the first sub-pixel 13A is constituted by one LED is shown, but the present disclosure is not limited to this structure, and each sub-pixel may be constituted by a plurality of light-emitting elements such as LEDs. For example, in the case of using a plurality of light-emitting elements for the purpose of increasing the brightness or the like, two or more light-emitting elements may be connected in series or in parallel. The same applies to the second sub-pixel.

[0136] (LED)

[0137] Figure 10 FIG. shows an example of an element structure in the case where an LED is used as the light-emitting element 11. The light-emitting element 11 shown in the figure includes an n-type semiconductor layer 2, an active layer 3, a p-type semiconductor layer 4, an n-side electrode 5, and a p-side electrode 6. The active layer 3 may use a multi-quantum well structure (MQW) or the like. The light-emitting element 11 is connected to a pixel drive circuit 8 such as a DC power supply, and emits light by receiving the supply of a drive current from the power supply line 9. The first light-emitting element 11A controls the light-emitting period at a prescribed drive current. The emission color of the first light-emitting element 11A is fixed to blue. In addition, the second light-emitting element 11B controls the second emission color by a drive current and controls the light-emitting period at the drive current. The second emission color can be changed to any color from green light to red light.

[0138] The first light-emitting element 11A has a constant chromaticity even when the brightness varies among the pixels 12. The brightness gray scale is controlled by PWM. On the other hand, the second light-emitting element 11B allows both the brightness and chromaticity to vary among the pixels 12. The current value supplied to the second light-emitting element 11B and the second emission color, i.e., the chromaticity, are controlled within the range of (G - R). Specifically, in each pixel 12, the second lighting control unit 50B acquires the chromaticities of RGB with reference to the information holding unit 70. Here, the chromaticity of B, i.e., the first emission color emitted by the first light-emitting element 11A, is uniquely determined. On the other hand, it is necessary to determine the second emission color of the second light-emitting element 11B. Here, first, according to the chromaticity signal to be displayed, the emission color when the (G - R) wavelength varies and the brightness ratio of B:(G - R) are determined in a manner corresponding to the color when B emits light. Then, the emission intensity corresponding to the brightness signal to be displayed is determined based on the chromaticity and brightness ratio of the emission color.

[0139] (Driving method of the light-emitting device)

[0140] Here, an example of the driving method of the light-emitting device 100 will be described. The lighting control unit 50 supplies driving currents to the first light-emitting element 11A and the second light-emitting element 11B through the first control circuit 51, and controls the light-emitting periods of the first light-emitting element 11A and the second light-emitting element 11B through the second control circuit 52. The process of the lighting control unit 50 driving these multiple first light-emitting elements 11A and multiple second light-emitting elements 11B1, 11B2, 11B3, 11B4 includes the following processes: according to the chromaticity signal and brightness signal to be displayed by the pixel 12, the second emission color and the brightness ratio between the first light-emitting element 11A and the second light-emitting element 11B are determined in a manner corresponding to the first emission color; based on the chromaticity and brightness ratio of the second emission color, the emission intensity corresponding to the brightness signal to be displayed is determined; the first control circuit 51 supplies driving current values corresponding to their respective emission colors to the first light-emitting element 11A and the second light-emitting element 11B with reference to the information holding unit 70; the second control circuit 52 controls the light-emitting periods of the driving current values supplied to the first light-emitting element 11A and the second light-emitting element 11B according to the determined emission intensity.

[0141] The first control circuit 51 controls the driving currents of the multiple first light-emitting elements 11A to be constant. The second control circuit 52 controls the emission intensity through PWM control. The driving current of the first light-emitting element 11A is set to a driving current value with good blue emission efficiency. For example, it is set to the rated current value.

[0142] In addition, the first control circuit 51 controls the emission color according to the current values for driving a plurality of second light-emitting elements 11B1, 11B2, 11B3, and 11B4. In addition, the second control circuit 52 controls the brightness by controlling the emission period of the current values of the plurality of second light-emitting elements 11B1, 11B2, 11B3, and 11B4 controlled by the first control circuit 51. Specifically, according to the chrominance signal and the luminance signal to be displayed on each pixel 12, the chrominance of the second emission color and the luminance ratio between the first light-emitting element 11A and the second light-emitting element 11B are determined in a manner corresponding to the first emission color. Then, based on the chrominance and the luminance ratio of the second emission color, the emission intensity corresponding to the luminance signal to be displayed by the second light-emitting element 11B is determined. Correspondingly, the first control circuit 51 refers to the information holding unit 70 to supply drive current values corresponding to their respective emission colors to the first light-emitting element 11A and the second light-emitting element 11B. In addition, the second control circuit 52 controls the emission periods of the first light-emitting element 11A and the second light-emitting element 11B according to the determined emission intensity.

[0143] (Method for determining drive current value and PWM emission period)

[0144] Here, based on Figure 11 the functional block diagram of Figure 12A and the chromaticity diagram of

[0145] the details of the steps for determining the drive current values and the PWM emission periods of the first light-emitting element 11A and the second light-emitting element 11B will be described. First, in step S1101, the drive control unit 60 acquires image data from an external source. The input data includes R luminance, G luminance, and B luminance. Figure 12A Next, in step S1102, a prescribed emission chrominance and luminance are determined for each pixel 12. Here, a point A on the xy chromaticity diagram of Figure 12A represents an arbitrary emission chrominance to be emitted. In this chromaticity diagram, the first light-emitting element 11A emits blue light as the first emission color, so it is fixed at point B near the lower left vertex of the chromaticity diagram. On the other hand, the second light-emitting element 11B emits light of the second emission color in any color between green light and red light. Therefore, if it is represented on the chromaticity diagram, it becomes any position between green near the upper vertex and red near the right vertex of the chromaticity diagram, point C. Therefore, the chrominance of point A represented by the mixed light of the first light-emitting element 11A and the second light-emitting element 11B can be represented by point B and point C. In other words, in order to represent the chrominance of point A, the emission color of the second light-emitting element 11B is adjusted in such a way as to adjust point C. Furthermore, considering the balance of the luminance between the first light-emitting element 11A and the second light-emitting element 11B, the luminance ratio of B:(G - R) is determined for the prescribed point A. Thus, the drive current value and the emission period of the second light-emitting element 11B at point C are determined.

[0146] Based on the above considerations, first, if the emission chromaticity of B (B) is considered according to the emission chromaticity of A (A) determined in step S1102 (step S1103), then the emission chromaticity of (G-R) (C) and the luminance ratio of B:(G-R) are determined (step S1104). When determining the luminance ratio of B:(G-R) in step S1104, based on the luminance at the emission chromaticity of (A) in step S1102, the luminance of (G-R) and the luminance of B are necessarily obtained (step S1108).

[0147] On the other hand, when determining the emission chromaticity of (G-R) (C) in step S1104, by referring to the emission chromaticity-driving current characteristic table of (G-R) held in the information holding unit 70 (step S1105), the driving current value of (G-R) is determined (step S1106).

[0148] Furthermore, when the driving current value of (G-R) is determined in step S1106, referring to the emission chromaticity-driving current-luminance characteristic table of (G-R) held in the information holding unit 70 (step S1107) and the luminance of (G-R) (step S1108), the PWM emission period of (G-R) is determined (step S1109).

[0149] On the other hand, based on the luminance of B obtained in step S1108, referring to the luminance characteristic value among the driving current values corresponding to the chromaticity of B (step S1110), the PWM emission period of B is determined (step S1111). In this way, the respective driving current values of the second light-emitting element 11B and the PWM emission periods of the first light-emitting element 11A and the second light-emitting element 11B are determined. In addition, the driving current value of the first light-emitting element 11A is the driving under the driving current value that maximizes the luminous efficiency when the first light-emitting element 11A emits light. In addition, as Figure 12A shown, the displayable range of point A in the present embodiment is Figure 12B compared with the case where the chromaticity range that can be displayed by the existing RGB three-color light-emitting pixels shown is triangular. In the present embodiment, the displayable chromaticity range is expanded, which is also another advantage of the present embodiment. In addition, by narrowing the full width at half maximum (FWHM) of the emission wavelength of the light-emitting element for point C, it is possible to further approach the outer edge on the chromaticity diagram. Such advantages are also the same in other embodiments described later.

[0150] [Embodiment 2]

[0151] In the above-described Embodiment 1, an example was described in which the unit sub-pixel group 13G was set to five sub-pixels, and four second light-emitting elements 11B were arranged. In contrast, one first light-emitting element 11A shared for constituting four pixels formed by these second light-emitting elements 11B was arranged. However, the present disclosure is not limited to this structure, and the unit sub-pixel group can also be less than four sub-pixels or six sub-pixels or more. Here, as the light-emitting device 200 of Embodiment 2, based on Figure 13 , Figure 14 an example will be described in which the unit sub-pixel group 13G is set to three sub-pixels, and one first light-emitting element 11A is arranged for every two second light-emitting elements 11B. In this example, the same reference numerals are given to the same components as those in the above-described Embodiment 1, and the detailed description thereof is omitted. In the light-emitting device 200 of this Embodiment 2, the first emission color is also fixed to blue light, and the second emission color is variable between green light and red light according to the drive current.

[0152] Figure 13 The display unit 10B shown in Figure 3 etc. relatively increases the number of first light-emitting elements 11A constituting one pixel 12B as compared with Figure 3 etc. In an example such as Figure 3 , the unit sub-pixel group 13G is set to five sub-pixels, and one first light-emitting element 11A is arranged for every four of the second light-emitting elements 11B1, 11B2, 11B3, and 11B4. In contrast, in Figure 13 , the unit sub-pixel group 13G is set to three sub-pixels, and one first light-emitting element 11A is arranged for every two of the second light-emitting elements 11B1 and 11B2. That is, the light-emitting device 200 of Embodiment 2 uses twice as many first light-emitting elements 11A as the light-emitting device 100 of Embodiment 1. As a result, higher-definition light emission than the light-emitting device 100 of Embodiment 1 can be achieved.

[0153] In the light-emitting device 200 of Embodiment 2, one pixel 12B is defined as the area surrounded by a right triangle in Figure 13 . That is, it is defined that in each pixel 12B formed in a pattern in which right triangles arranged with the hypotenuse as the vertical direction are repeated, the second light-emitting elements 11B arranged in a matrix are respectively included near the right angle. In addition, the first light-emitting element 11A is defined to exist only about 1 / 2 in a manner straddling the hypotenuse near the acute angle of the right triangle. As a result, the area ratio of the first light-emitting element 11A in one pixel 12B is about 1 / 2 of that of the second light-emitting element 11B.

[0154] One first light-emitting element 11A disposed on the hypotenuse of a right triangle forming one pixel 12B is shared by approximately 1 / 2 of the areas of two adjacent pixels 12B. In other words, each first light-emitting element 11A is disposed in a manner that straddles two pixels 12B on the common hypotenuse of two adjacent pixels 12B. However, the first light-emitting elements 11A are not disposed in all areas surrounded by four adjacent second light-emitting elements 11B, but are disposed in every other space surrounded by four second light-emitting elements 11B.

[0155] To achieve such a configuration, in Figure 14 the example of, when capturing the second light-emitting elements 11B arranged in a matrix on the extension line in the diagonal direction of the display unit 10B, the first light-emitting elements 11A are disposed between two adjacent second light-emitting elements 11B in the diagonal direction. As a result, the second light-emitting elements 11B and the first light-emitting elements 11A are in a state of being alternately arranged in the diagonal direction. The extension line (referred to as the alternate arrangement line) in the diagonal direction where such second light-emitting elements 11B and first light-emitting elements 11A are alternately arranged is provided every other row in the diagonal direction of the display unit 10B.

[0156] In Figure 14 one unit sub-pixel group 13G2 becomes a rhombus region surrounded by solid lines. That is, the second light-emitting elements 11B1 and 11B2 included in two adjacent pixels 12A and 12B that share hypotenuses with each other are two (i.e., two sub-pixels), and the first light-emitting element 11A is one (i.e., one sub-pixel), and a total of three sub-pixels constitute the unit sub-pixel group 13G2. The emission color and brightness of the unit sub-pixel group 13G2 are determined by these three sub-pixels. Here, as the steps for determining the emission color and emission brightness of each sub-pixel constituting the unit sub-pixel group 13G2, first, the emission color of the unit sub-pixel group 13G2 is determined. When the emission color of the unit sub-pixel group 13G2 is determined, the emission colors of the two second light-emitting elements 11B1 and 11B2 included in the unit sub-pixel group 13G2 are determined. That is, the emission colors of these two second light-emitting elements 11B1 and 11B2 are the same. Next, the emission brightness of each pixel 12B is determined. When determining the emission brightness of each pixel, it is necessary to determine the drive current value and emission period of each sub-pixel constituting each pixel.

[0157] Here, based on Figure 5 the flowchart of, the steps for determining the drive current value and emission period of each sub-pixel are described. First, as step S501, for each unit sub-pixel group 13G, the average chromaticity and average brightness in the image data to be displayed are determined. In Figure 14In the example, the average chromaticity and average brightness are calculated for each unit sub-pixel group 13G2 for the three light-emitting elements 11, namely, the first light-emitting element 11A and the two second light-emitting elements 11B1 and 11B2 adjacent thereto, which constitute the three sub-pixels of the unit sub-pixel group 13G2. In addition, in this structure, although the fineness of the chromaticity is reduced to 1 / 2, the color resolution of the human eye is lower than the brightness resolution, so the degradation of the image quality is not perceived.

[0158] Next, as step S502, the average chromaticity and average brightness of the second light-emitting elements 11B1 and 11B2 in the unit sub-pixel group 13G2, and the chromaticity and brightness of the first light-emitting element 11A are determined respectively using a prescribed algorithm. Here, the average brightness of the two second light-emitting elements 11B1 and 11B2 is determined by the light-emitting period of the second light-emitting element 11B. In addition, the chromaticity of the first light-emitting element 11A is determined by the driving current value, and the brightness is determined by the light-emitting period. In addition, the second light-emitting elements 11B1 and 11B2 in the unit sub-pixel group 13G2 emit light with the same chromaticity as the same driving current value. Figure 14 In the example of , the second light emitting elements 11B1 and 11B2 of the two sub-pixels emit the same light color. In addition, the predetermined algorithm for determining the average chromaticity and average brightness of the second light emitting element 11B and the chromaticity and brightness of the first light emitting element 11A is as shown in Figure 11 As described in .

[0159] Finally, as step S503, the brightness of each sub-pixel belonging to the unit sub-pixel group 13G is determined. That is, the secondary brightness of the second light-emitting element 11B is allocated according to the brightness of each sub-pixel belonging to the unit sub-pixel group 13G2, and the brightness of each sub-pixel is determined. The brightness of the second light-emitting element 11B is determined by the light-emitting period. Here, the light-emitting period of the second light-emitting element 11B is allocated according to the ratio of the brightness signals of the three sub-pixels constituting the unit sub-pixel group 13G2, and the light-emitting period of each pixel 12B is determined. As described above, the brightness of each pixel 12B can be determined after the chromaticity of each unit sub-pixel group 13G2 is determined.

[0160] [Implementation method 3]

[0161] Furthermore, as a light emitting device 300 according to Embodiment 3, based on Figure 15 The following describes an example in which the unit sub-pixel group 13G is set to two sub-pixels, and one first light-emitting element 11A is configured for each second light-emitting element 11B. In this example, the same reference numerals are given to the same components as those in the above-mentioned embodiment 1, and detailed descriptions are omitted. In the light-emitting device 300 of this embodiment 3, the first light-emitting color is also fixed to blue light, and the second light-emitting color is variable from green light to red light according to the driving current.

[0162] Figure 15 The display unit 10C shown and Figure 3 Compared with etc., the number of the first light-emitting elements 11A constituting one pixel 12C is relatively further increased. In Figure 3 In the example of, the unit sub-pixel group 13G is set to 5 sub-pixels, and in Figure 14 the unit sub-pixel group 13G is set to 3 sub-pixels. In contrast, in Figure 15 the unit sub-pixel group 13G is set to 2 sub-pixels, and one first light-emitting element 11A is arranged for each second light-emitting element 11B. That is, the light-emitting device 300 of Embodiment 3 uses four times as many first light-emitting elements 11A as the light-emitting device 100 of Embodiment 1. Thereby, no reduction in the fineness of chromaticity occurs, and a higher-fineness light-emitting display can be further achieved with respect to the light-emitting device 100 of Embodiment 1. On the other hand, the number of sub-pixels is increased compared with the light-emitting device 100 of Embodiment 1.

[0163] In the light-emitting device 300 of Embodiment 3, as Figure 15 shown by the region surrounded by the dashed line in, one pixel 12C is defined. That is, one pixel 12C is constituted by the first light-emitting elements 11A adjacent to each second light-emitting element 11B. As a result, the number of the first light-emitting elements 11A in one pixel 12C is one, which is twice that of Embodiment 2.

[0164] In Figure 15 the example of, different from Figure 3 and Figure 14 the first light-emitting elements 11A are arranged in all the regions surrounded by the adjacent 4 second light-emitting elements 11B. In other words, in all the alternately arranged lines, the first light-emitting elements 11A are arranged between two diagonally adjacent second light-emitting elements 11B. In addition, in Figure 15 an example is shown in which one pixel 12C is constituted by the second light-emitting element 11B located at the lower right among the 4 second light-emitting elements 11B adjacent to the periphery of each first light-emitting element 11A. However, this is merely an example, and one pixel 12C may be constituted by other second light-emitting elements 11B adjacent to the periphery of each first light-emitting element 11A, such as the second light-emitting element 11B at the upper right, upper left, or lower left.

[0165] In Figure 15In this case, a unit sub-pixel group 13G becomes the region surrounded by the solid line. Here, it is composed of a total of two sub-pixels, namely, one second light-emitting element 11B (i.e., one sub-pixel) and one adjacent first light-emitting element 11A (i.e., one sub-pixel). That is, in Embodiment 3, one pixel 12C and the unit sub-pixel group 13G coincide. The light-emitting color and brightness of the unit sub-pixel group 13G2 are determined by these two sub-pixels. Here, as the steps of determining the light-emitting color and light-emitting brightness of each sub-pixel constituting the unit sub-pixel group 13G3, first, the light-emitting color of the unit sub-pixel group 13G3 is determined. If the light-emitting color of the unit sub-pixel group 13G3 is determined, then the light-emitting colors of the first light-emitting element 11A and the second light-emitting element 11B constituting the unit sub-pixel group 13G3 are determined. Next, the light-emitting brightness of each sub-pixel is determined.

[0166] Here, based on Figure 16 The flowchart of determines the driving current value and the light-emitting period of each sub-pixel. Here, since there is one second light-emitting element 11B included in the unit sub-pixel group 13G3, it is not necessary to calculate the average chromaticity and average brightness. Therefore, as step S1601, for each unit sub-pixel group 13G3, using a prescribed algorithm, the chromaticity and brightness of the second light-emitting element 11B and the first light-emitting element 11A in the unit sub-pixel group 13G3 are respectively determined. Here, the chromaticity of the second light-emitting element 11B is determined by the driving current value, and the brightness is determined by the light-emitting period of the second light-emitting element 11B. In addition, the chromaticity of the first light-emitting element 11A is determined by the driving current value, and the brightness is determined by the light-emitting period. In addition, the prescribed algorithms for respectively determining the average chromaticity and average brightness of the second light-emitting element 11B and the chromaticity and brightness of the first light-emitting element 11A are as described with reference to Figure 11 As described above, it is possible to determine the brightness of each pixel 12C on the basis of determining the chromaticity of each unit sub-pixel group 13G.

[0167] [Embodiment 4]

[0168] In the above embodiments, examples of offsetting the first light-emitting elements 11A between the second light-emitting elements 11B arranged in a matrix are described. For example, in Figure 15 an example of arranging the first light-emitting elements 11A in all regions surrounded by four adjacent second light-emitting elements 11B is described, and in the example of Figure 14 an example of arranging the first light-emitting elements 11A every other second light-emitting element 11B is described, and in Figure 3The example in which the first light-emitting element 11A is arranged for every four second light-emitting elements 11B is described. In any example, the first light-emitting element 11A is arranged between the second light-emitting elements 11B arranged in a matrix at equal intervals. Therefore, the distance between the first light-emitting element 11A and the second light-emitting element 11B is shorter than the distance between the second light-emitting elements 11B. However, the present disclosure is not limited to such a configuration example, and the first light-emitting element may be arranged at equal intervals from the second light-emitting element. Such an example is shown as Embodiment 4 in Figure 17 . In this figure, the same reference numerals are assigned to the same components as those in the above-described Embodiment 1 and the detailed description thereof is omitted. In the light-emitting device 400 of this Embodiment 4, the first emission color is also fixed to blue light, and the second emission color is variable between green light and red light according to the drive current.

[0169] In Figure 17 the display unit 10D shown, as shown by the solid-line frame in the figure, the unit sub-pixel group 13G is composed of a total of four sub-pixels, namely, one first light-emitting element 11A (i.e., one sub-pixel) and three second light-emitting elements 11B (i.e., three sub-pixels). In this structure, one pixel 12D is computationally composed of one second light-emitting element 11B and about 1 / 3 of the first light-emitting element 11A. In Figure 17 , one pixel 12D is indicated by a dotted line. In this example, three pixels share the first light-emitting element 11A and are arranged to partially overlap in a rectangle extending in the right, upper, and left three directions. In addition, the second light-emitting element 11B and the first light-emitting element 11A are arranged in every other row in the horizontal direction such that there are rows in which the second light-emitting element 11B and the first light-emitting element 11A are mixed and present at equal intervals and rows composed only of the second light-emitting element 11B. In the rows in which the second light-emitting element 11B and the first light-emitting element 11A are mixed and present, these second light-emitting elements 11B and the first light-emitting element 11A are repeatedly arranged at equal intervals such that one first light-emitting element 11A is arranged for every two second light-emitting elements 11B. In addition, in the rows composed only of the second light-emitting element 11B, corresponding to the positions where the first light-emitting element 11A is arranged in the rows in which the second light-emitting element 11B and the first light-emitting element 11A are mixed and present adjacent to the upper and lower sides, the second light-emitting element 11B is arranged at a first distance away from the first light-emitting element 11A on the upper and lower sides. As a result, in the rows composed only of the second light-emitting element 11B, the second light-emitting element 11B is arranged every other two compared with the upper and lower rows.

[0170] In Figure 17In this case, the emission color and luminance of the unit sub-pixel group 13G are also determined by the four sub-pixels that constitute a unit sub-pixel group 13G4. That is, first, the emission color of the unit sub-pixel group 13G4 is determined, and then the emission colors of the first light-emitting element 11A and the second light-emitting element 11B that constitute the unit sub-pixel group 13G4 are determined. Furthermore, the emission luminance of each sub-pixel is determined. The steps of determining the drive current value and emission period of each specific sub-pixel are the same as those in Figure 5 the flowchart of

[0171] [Embodiment 5]

[0172] In the light-emitting device of each of the above embodiments, an example has been described in which the first emission color is blue light and the second emission color is variable between green light and red light. However, the present disclosure is not limited to this structure, and other emission colors can also be assigned to the first emission color and the second emission color. As an example, in the light-emitting device 500 of Embodiment 5, the first emission color is fixed to red light, and the second emission color is variable between green light and blue light according to the drive current. By adopting such a structure, it is possible to form one pixel with two light-emitting elements, namely, the first light-emitting element 11A capable of emitting red light and the second light-emitting element 11B capable of emitting light from blue light to green light, without arranging the three sub-pixels of RGB in each pixel 12E, and the light-emitting device can be formed with a smaller number of light-emitting elements. In addition, in the second light-emitting element 11B, which is a wavelength-variable light-emitting element, even if the control is not performed over the entire chromaticity range of RGB, the control can be performed from blue to green, so that the advantages of improving the yield during manufacturing and simplifying the control during lighting can be obtained.

[0173] As the first light-emitting element 11A, a quaternary semiconductor light-emitting element such as AlInGaP can be used. Thereby, the luminous efficiency of the first light-emitting element 11A that emits red light can be improved. In addition, the advantages that a widely popular red light-emitting diode can be used stably and inexpensively can be obtained.

[0174] Figure 18Shows the display unit 10E of the light-emitting device 500 according to Embodiment 5. In this example, the same reference numerals are given to the same components as those in the above-described Embodiment 1 and the like, and detailed descriptions thereof are omitted. As shown in this figure, the display unit 10E is provided with a first light-emitting element 11A and a second light-emitting element 11B for each of the pixels 12E. Here, an example is shown in which one first light-emitting element 11A and one second light-emitting element 11B are arranged in each pixel 12E, and one pixel 12E is composed of two sub-pixels. The first light-emitting element 11A is a red light-emitting element, and the second light-emitting element 11B is a variable light emission that can change the emission wavelength from blue light to green light by a drive current. For red light, the emission wavelength is set to 630 nm, for example. In addition, the emission wavelength is variable in the range of 470 nm to 530 nm from blue light to green light, for example.

[0175] At Figure 19 On the chromaticity diagram of, the point D represents an arbitrary emission chromaticity at which the first light-emitting element 11A of the red light-emitting element and the second light-emitting element 11B of the variable light emission from blue light to green light are to emit light. In this chromaticity diagram, since the first light-emitting element 11A emits red light as the first emission color, it is fixed at point E near the lower right vertex of the chromaticity diagram. On the other hand, since the second light-emitting element 11B emits the second emission color light in any color between blue light and green light, if it is represented on the chromaticity diagram, it becomes any position between green near the upper vertex of the chromaticity diagram and blue near the left vertex, point F. Therefore, the chromaticity of point D represented by the mixed color light of the first light-emitting element 11A and the second light-emitting element 11B can be represented by point E and point F. In other words, in order to represent the chromaticity of point D, the emission color of the second light-emitting element 11B is adjusted in such a way as to adjust point F. Further, considering the balance of the brightness of the first light-emitting element 11A and the second light-emitting element 11B, the brightness ratio of R:(B - G) is determined for a specified point D. Thus, the drive current value and the emission period of the second light-emitting element 11B at point F are determined. In this way, even without the emission of monochromatic light in the range from green light to red light, a sufficiently large chromaticity range can be achieved. In addition, it is also possible to perform a display of cyan with high color purity, which has been difficult to represent in the past.

[0176] Here, based on Figure 20 The flowchart of shows the steps of determining the drive current value and the emission period of each sub-pixel. First, as step S2001, in each pixel 12E, based on the emission color to be displayed by the pixel 12E, the second emission color for causing the second light-emitting element 11B to emit light and the brightness ratio of the first light-emitting element 11A and the second light-emitting element 11B are calculated. Here, according to the chromaticity signal of the image data, the emission color from blue light to green light of the second light-emitting element 11B is determined in a manner corresponding to the red light R of the first light-emitting element 11A ( Figure 19on the chromaticity diagram of F) and the luminance ratio of R:B-G (equivalent to Figure 19 on the chromaticity diagram of D).

[0177] Next, in step S2002, the light emission intensity of the second light-emitting element 11B is calculated. Here, based on the red light that is the first light-emitting color of the first light-emitting element 11A and the chromaticity and luminance ratio (D) of the light-emitting color (F) from blue light to green light of the second light-emitting element 11B obtained in step S2001, the light emission intensity corresponding to the luminance signal to be displayed by the second light-emitting element 11B is determined. In this way, the chromaticity and luminance of each sub-pixel can be determined.

[0178] In addition, in Figure 18 the example, an example is shown in which one first light-emitting element 11A and one second light-emitting element 11B are respectively arranged in each pixel 12E, but the present disclosure is not limited to this structure, and two or more first light-emitting elements or second light-emitting elements may be arranged in one pixel. Thereby, the luminance of each pixel can be increased.

[0179] In the light-emitting device 100 of the above-described Embodiment 1, a first light-emitting element 11A and a second light-emitting element 11B are provided for each pixel 12 respectively. And, as Figure 21A shown, the first light-emitting element 11A is a fixed-wavelength light-emitting element of blue light, and the second light-emitting element 11B is a variable-wavelength light-emitting element from green light to red light. In this example, one first light-emitting element 11A and one second light-emitting element 11B are respectively provided in each pixel 12, but a plurality of either one or both of the first light-emitting element and the second light-emitting element may be provided for each pixel. Thereby, the light emission luminance can be increased.

[0180] [Embodiment 6]

[0181] In addition, the present disclosure is not limited to the structure in which the first light-emitting element is a fixed wavelength and the second light-emitting element is a variable wavelength, and the first light-emitting element may also be a variable-wavelength light-emitting element. An example of such a light-emitting device 600 of Embodiment 6 is shown in Figure 21B . In addition, in Figure 21A , Figure 21B the shown example, the fixed-wavelength light-emitting element is represented by a quadrilateral, and the variable-wavelength light-emitting element is represented by a hatched quadrilateral. In addition, regarding the variable-wavelength light-emitting element, it is shown that the light emission wavelength is variably driven within the range from the light-emitting color in the upper left region divided by the slashes of the quadrilateral to the light-emitting color in the lower right region. Here, dividing the quadrilateral with slashes is merely for the purpose of indicating the change in the light emission wavelength, and it does not mean that the light-emitting region of the light-emitting element is physically divided by the slashes to emit light with different light-emitting colors for each region.

[0182] In Figure 21A the light-emitting device 100 of Embodiment 1 shown, the first light-emitting element 11A is of a fixed wavelength type, and the second light-emitting element 11B is of a variable wavelength type, and the light-emitting wavelength is made variable and used in the range of light-emitting colors from red R to green G. In contrast, in Figure 21B Embodiment 6 shown, the first light-emitting element 11A' also uses a variable wavelength type light-emitting element, and its light-emitting wavelength is fixed to blue B and driven.

[0183] In addition, regardless of the actually driven light-emitting wavelength range, the variable range of the light-emitting wavelength of the variable wavelength type light-emitting element for the first light-emitting element 11A' can be B-G, and even if it is B-R or B-Y, as long as B that becomes the first light-emitting color is included in the variable range of the light-emitting wavelength. In addition, at this time, regardless of the actually driven light-emitting wavelength range, if the variable wavelength ranges of the light-emitting wavelengths of the variable wavelength type light-emitting element used for the first light-emitting element 11A' and the variable wavelength type light-emitting element used for the second light-emitting element 11B are both variable in B-R, then each pixel 12F can be configured using a single specification of light-emitting element, and thus the advantage of simplifying the manufacturing process of the pixel 12F can be obtained. Similarly, as in Embodiment 4, when the first light-emitting color is set to red R, the variable range of the light-emitting wavelength of the variable wavelength type light-emitting element used for the first light-emitting element 11A' becomes a range including R.

[0184] In addition, in order to fix the variable wavelength type first light-emitting element 11A' to the first light-emitting color of blue light and cause it to emit light, the information holding unit 70 holds not only the current-chromaticity information of the second light-emitting element 11B but also the current-chromaticity information of the first light-emitting element 11A', etc. The lighting control unit 50 refers to the information holding unit 70 and determines the drive current of the first light-emitting element 11A' corresponding to the first light-emitting color. Furthermore, by making the first light-emitting element 11A' of the variable wavelength type, the wavelength of the blue light can also be adjusted. For example, the deviation of the light-emitting wavelength of the first light-emitting element 11A' can be corrected between the pixels 12F so that the wavelengths of the blue light of each pixel 12F are the same.

[0185] In addition, in the above examples, the active matrix driving method has been described, but the present disclosure can also be applied to the passive matrix driving method.

[0186] Industrial Applicability

[0187] The light-emitting device and the driving method of the light-emitting device of the present disclosure can be suitably used for, for example, medium-sized or large-sized displays, indicators, or signs.

Claims

1. A light-emitting device, comprising: a display unit, wherein a plurality of first light-emitting elements capable of emitting light of a first light-emitting color and a plurality of second light-emitting elements capable of emitting light of a second light-emitting color different from the first light-emitting color are arranged in a predetermined pattern to form a plurality of pixels; A lighting control unit supplies driving current to the plurality of first light emitting elements and the plurality of second light emitting elements respectively to control the light emitting period, wherein: The second light emitting element can control the second light emitting color according to the driving current, The pixel is configured by arranging the first light emitting element and the second light emitting element so as to emit light of the first light emitting color and light of the second light emitting color.

2. The light emitting device according to claim 1, wherein: The device further comprises an information storage unit, the information storage unit storing current-chromaticity information, the current-chromaticity information being used to determine a driving current value for causing the first light emitting element and the second light emitting element to emit light according to a predetermined light emitting color of the plurality of pixels, The lighting control unit controls the plurality of first light emitting elements and the plurality of second light emitting elements based on the current-chromaticity information held by the information holding unit so that the plurality of first light emitting elements and the plurality of second light emitting elements respectively emit light at a prescribed light color and light brightness.

3. The light emitting device according to claim 1 or 2, wherein: The lighting control unit comprises: a first control circuit that supplies a driving current to the first light emitting element and the second light emitting element; The second control circuit controls the light-emitting periods of the first light-emitting element and the second light-emitting element.

4. The light emitting device according to claim 3, wherein: At least one of the first control circuit and the second control circuit is provided for each pixel.

5. The light emitting device according to claim 3 or 4, wherein: The pixel is configured to emit light of the first emission color emitted by at least one of the first light emitting elements and light of the second emission color emitted by at least one of the second light emitting elements.

6. The light emitting device according to any one of claims 1 to 5, wherein: The first luminescent color is blue light.

7. The light emitting device according to claim 6, wherein: The first luminescent color is luminescent with a fixed wavelength.

8. The light emitting device according to any one of claims 1 to 7, wherein: The second light emission color is variable between green light and red light according to a driving current of the second light emitting element.

9. The light emitting device according to claim 8, wherein: The display unit configures at least one of the plurality of second light emitting elements for each pixel. The plurality of first light emitting elements are arranged so as to straddle adjacent pixels.

10. The light emitting device according to claim 9, wherein: The display unit is configured by periodically arranging sub-pixel groups, and the sub-pixel groups are configured such that the first light-emitting elements and the second light-emitting elements constituting each pixel are adjacent to each other in a predetermined pattern.

11. The light emitting device according to claim 9 or 10, wherein: In the display unit, the second light emitting elements are arranged inside a quadrilateral that divides each pixel, and the first light emitting elements are arranged at corners of the quadrilateral.

12. The light emitting device according to any one of claims 1 to 5, wherein: The first luminous color is red light, The second emission color is variable between green light and blue light according to a driving current.

13. The light emitting device according to claim 12, wherein: The display unit is configured such that at least one of the plurality of first light emitting elements and at least one of the plurality of second light emitting elements are arranged for each pixel.

14. The light emitting device according to claim 12 or 13, wherein: The first light emitting element is a red light emitting diode.

15. The light emitting device according to any one of claims 3 to 14, wherein: The chromaticity of the second luminous color and the luminance ratio between the first luminous element and the second luminous element are determined in a manner corresponding to the first luminous color based on the chromaticity signal and luminance signal to be displayed by each pixel. determining the light emission intensity corresponding to the brightness signal to be displayed by the second light emitting element based on the chromaticity of the second light emission color and the brightness ratio, The first control circuit refers to the information storage unit to supply driving current values ​​corresponding to the respective emission colors to the first light emitting element and the second light emitting element. The second control circuit controls a light emission period of the driving current value supplied by the first control circuit according to the determined light emission intensity.

16. The light emitting device according to any one of claims 1 to 15, wherein: The lighting control unit is configured to set a time width for supplying current to the first light emitting element and the second light emitting element based on a result of comparing a first signal including a triangular wave signal with a first DC voltage set in a predetermined period, A current value supplied to the lighting control unit is controlled based on a second DC voltage set in a period different from the predetermined period.

17. A method for driving a light emitting device, the light emitting device comprising: A display unit, wherein a plurality of first light emitting elements capable of emitting light of a first light emitting color and a plurality of second light emitting elements capable of emitting light of a second light emitting color different from the first light emitting color and capable of controlling the light emitting color according to a driving current are arranged in a predetermined pattern to form a plurality of pixels; a lighting control unit that supplies driving current to each of the plurality of first light emitting elements and the plurality of second light emitting elements to control a light emitting period; The driving method of the light emitting device comprises the following steps: preparing the display unit in which the first light emitting element and the second light emitting element are arranged so that each pixel emits light of the first light emitting color and light of the second light emitting color; The lighting control unit supplies a driving current to each of the plurality of first light emitting elements and the plurality of second light emitting elements, and controls a light emission period to light the elements.

18. The driving method of the light emitting device according to claim 17, wherein: The device further comprises an information storage unit that stores current-chromaticity information that determines a driving current value for causing the first light emitting element and the second light emitting element to emit light according to a predetermined light emission color of the plurality of pixels. The step of the lighting control unit lighting the plurality of first light emitting elements and the plurality of second light emitting elements includes the following steps: Determining the chromaticity of the second luminescent color and the luminance ratio between the first luminescent element and the second luminescent element in a manner corresponding to the first luminescent color based on the chromaticity signal and the luminance signal to be displayed in the pixel; determining a light emission intensity corresponding to a brightness signal to be displayed based on the chromaticity of the second light emission color and the brightness ratio; The first control circuit of the lighting control unit refers to the information holding unit to supply the first light emitting element and the second light emitting element with driving current values ​​corresponding to the respective light emission colors; The second control circuit of the lighting control unit controls a light emission period of the driving current value supplied by the first control circuit according to the determined light emission intensity.

19. The driving method of the light emitting device according to claim 18, wherein: The step of the lighting control unit lighting the plurality of first light emitting elements and the plurality of second light emitting elements includes the following steps: The second control circuit controls the light emission intensity by PWM control in a state where the driving current of the plurality of first light emitting elements is kept constant; The first control circuit controls the light emission color according to the current value driving the plurality of second light emitting elements; The second control circuit controls brightness according to a light emission period of a current value of the plurality of second light emitting elements controlled by the first control circuit.

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