Display device

Abstract

The display device includes: a circuit substrate, which includes a first pixel and a second pixel; a first LED chip, which overlaps with the first anode pad and the first cathode pad of the first pixel; and a second LED chip, which overlaps with the second anode pad and the second cathode pad of the second pixel, wherein the first pixel is located between the first anode pad and the first cathode pad, and includes a first light-transmitting area that allows light from the first LED chip to pass through, and the second pixel includes a second light-transmitting area that is located between the second anode pad and the second cathode pad and allows light from the second LED chip to pass through, and when looking down at the circuit substrate, a first area of the first light-transmitting area and a second area of the second light-transmitting area have a first ratio, and the first ratio is first area:second area = 1:0.8 to 1.2.

Description

Technical Field

[0001] One embodiment of the present invention relates to a display device, and more particularly, to a display device using an LED chip. Background Art

[0002] In small and medium-sized display devices such as smartphones, display devices using liquid crystals and OLEDs (Organic Light Emitting Diodes) have been commercialized. Among them, OLED display devices using OLEDs as self-luminous elements have the advantages of high contrast and no need for backlight compared to liquid crystal display devices. OLEDs are transparent by using transparent conductive materials in two electrodes (anode and cathode), and emit light on both sides (the surface on the anode side and the surface on the cathode side) at the same time (for example, see Patent Document 1). However, OLEDs are composed of organic compounds, so it is difficult to ensure the high reliability of OLED display devices due to the deterioration of organic compounds.

[0003] In recent years, so-called micro-LED display devices and mini-LED display devices, which incorporate tiny LED chips within the pixels of a circuit substrate, have been developed as next-generation display devices (see, for example, Patent Documents 2 and 3). LEDs are self-luminous elements, similar to OLEDs, but unlike OLEDs, they are composed of inorganic compounds such as gallium (Ga) and indium (In). Therefore, compared to OLED displays, micro-LED displays are more likely to achieve high reliability. Furthermore, LED chips have high luminous efficiency and can also achieve high brightness. Therefore, micro-LED displays are expected to be the next generation of display devices with high reliability, high brightness, and high contrast.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-3849

[0007] Patent Document 2: U.S. Patent No. 10,090,335

[0008] Patent Document 3: Chinese Patent Application Publication No. 110190085 Summary of the Invention

[0009] Technical problem to be solved by the invention

[0010] Micro-LED and mini-LED displays also achieve transparent, dual-sided displays by refining the structure of LEDs or the mounting of LED chips. However, in micro-LED and mini-LED displays, the circuit substrate on which the LED chips are mounted has numerous wiring and electrodes. Therefore, the brightness of the LED chip's light, as seen from the circuit substrate, depends on the arrangement of the wiring and electrodes. Specifically, the brightness decreases when there are more wiring and electrodes in the area overlapping the LED chip, while the brightness increases when there are fewer wiring and electrodes in the area overlapping the LED chip. Consequently, when the LED chip's light is extracted from the circuit substrate, the brightness of the pixels varies depending on the arrangement of the pixels.

[0011] In view of the above-mentioned problems, one embodiment of the present invention aims to suppress variations in brightness between pixels in a display device in which LED chips mounted on a circuit board emit light at least toward the circuit board. Furthermore, another technical problem of one embodiment of the present invention is to provide a display device capable of displaying a display with excellent color balance, even when equipped with LED chips of multiple luminous colors.

[0012] Means for solving technical problems

[0013] A display device according to one embodiment of the present invention includes: a circuit substrate including a first pixel and a second pixel; a first LED chip installed so as to overlap with and be electrically connected to a first anode pad and a first cathode pad of the first pixel; and a second LED chip installed so as to overlap with and be electrically connected to a second anode pad and a second cathode pad of the second pixel, including a first light-transmitting area in which the first pixel overlaps with the first LED chip, is located between the first anode pad and the first cathode pad, and transmits light from the first LED chip; the second pixel overlaps with the second LED chip, is located between the second anode pad and the second cathode pad, and includes a second light-transmitting area in which light from the second LED chip transmits light; when the circuit substrate is viewed from above, a first area of the first light-transmitting area and a second area of the second light-transmitting area have a first ratio, the first ratio being first area:second area = 1:0.8 to 1.2.

[0014] A display device of one embodiment of the present invention includes: a first insulating layer above the light-shielding layer; a first wiring layer above the first insulating layer; a second insulating layer above the first wiring layer; an anode pad connected to the LED chip above the second insulating layer; and a cathode pad connected to the LED chip above the second insulating layer, wherein the light-shielding layer is located between the anode pad and the cathode pad when viewed from above. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is a schematic plan view of a display device according to one embodiment of the present invention.

[0016] Figure 2 This is a schematic cross-sectional view of a pixel of a display device according to one embodiment of the present invention.

[0017] Figure 3 This is a schematic cross-sectional view of an LED chip mounted on a display device according to one embodiment of the present invention.

[0018] Figure 4 This is a circuit diagram showing a circuit (pixel circuit) for driving an LED chip in a pixel of a display device according to one embodiment of the present invention.

[0019] Figure 5 This is a schematic plan view of a pixel of a display device according to one embodiment of the present invention.

[0020] Figure 6A This is a schematic plan view showing the positional relationship between the anode pad and cathode pad of the circuit board and the LED chip in the display device according to one embodiment of the present invention.

[0021] Figure 6B This is a schematic plan view showing the positional relationship between the anode pad and cathode pad of the circuit board and the LED chip in the display device according to one embodiment of the present invention.

[0022] Figure 6C This is a schematic plan view showing the positional relationship between the anode pad and cathode pad of the circuit board and the LED chip in the display device according to one embodiment of the present invention.

[0023] Figure 6D This is a schematic plan view showing the positional relationship between the anode pad and cathode pad of the circuit board and the LED chip in the display device according to one embodiment of the present invention.

[0024] Figure 7A This is a schematic plan view showing a light-transmitting region whose area is adjusted in a display device according to one embodiment of the present invention.

[0025] Figure 7B This is a schematic plan view showing a light-transmitting region whose area is adjusted in a display device according to one embodiment of the present invention.

[0026] Figure 7C This is a schematic plan view showing a light-transmitting region whose area is adjusted in a display device according to one embodiment of the present invention.

[0027] Figure 7DThis is a schematic plan view showing a light-transmitting region whose area is adjusted in a display device according to one embodiment of the present invention.

[0028] Figure 8A This is a schematic plan view showing three pixels included in a display portion of a circuit substrate in a display device according to one embodiment of the present invention.

[0029] Figure 8B This is a schematic plan view showing three pixels included in a display portion of a circuit substrate in a display device according to one embodiment of the present invention.

[0030] Figure 8C This is a schematic plan view showing three pixels included in a display portion of a circuit substrate in a display device according to one embodiment of the present invention.

[0031] Figure 9 This is a schematic plan view showing an arrangement of pixels in a display unit of a display device according to one embodiment of the present invention.

[0032] Figure 10 This is a schematic plan view showing an arrangement of pixels in a display unit of a display device according to one embodiment of the present invention.

[0033] Figure 11 This is a schematic plan view showing an arrangement of pixels in a display unit of a display device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following describes various embodiments of the present invention with reference to the accompanying drawings. Each embodiment is merely an example, and variations that can be readily devised by those skilled in the art while maintaining the spirit of the invention are naturally within the scope of the present invention. Furthermore, to clarify the description, the drawings sometimes schematically illustrate the width, thickness, and shape of various components, as compared to actual configurations. However, the illustrated shapes are merely examples and do not limit the scope of the present invention.

[0035] In this specification, expressions such as "α includes A, B, or C," "α includes any one of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude the case where α includes multiple combinations of A to C, unless otherwise specified. Furthermore, these expressions do not exclude the case where α includes other elements.

[0036] In this specification, for the sake of convenience, the terms "upper", "above", "lower", or "below" are used for explanation. In principle, the direction from the substrate toward the structure is defined as "upper" or "above" based on the substrate forming the structure. Conversely, the direction from the structure toward the substrate is defined as "lower" or "below". Therefore, in the representation of the structure on the substrate, the surface of the structure on the substrate side is the lower surface, and the surface on the opposite side is the upper surface. In addition, in the representation of the structure on the substrate, it is only to illustrate the upper and lower relationship between the substrate and the structure, and other components may be arranged between the substrate and the structure. Furthermore, the terms "upper", "above", "lower", or "below" refer to the stacking order of a structure having multiple layers, and the positions do not need to be in an overlapping relationship when viewed from above.

[0037] In this specification, a “display device” broadly includes devices that display images, including not only display panels and display modules but also devices equipped with other optical components (eg, polarization components or touch panels).

[0038] The following embodiments can be combined with each other as long as no technical contradiction occurs.

[0039] <First embodiment>

[0040] Reference Figures 1 to 8C , a display device 10 according to one embodiment of the present invention is described.

[0041] [1. Overview of the Structure of the Display Device]

[0042] Figure 1 1 is a schematic top view of a display device 10 according to an embodiment of the present invention. Specifically, Figure 1 It is a block diagram showing the structure of the planar layout of the display device 10 .

[0043] like Figure 1 As shown, the display device 10 includes a circuit substrate 100 and a light-emitting diode chip (LED chip) 200. The circuit substrate 100 includes a display portion 210, a first circuit portion 220L, a second circuit portion 220R, and a connection portion 230. The display portion 210 is provided in the center of the circuit substrate 100, while the first circuit portion 220L, the second circuit portion 220R, and the connection portion 230 are provided at the periphery of the circuit substrate 100.

[0044] The display unit 210 includes a plurality of pixels 212. An LED chip 200 is mounted on each of the plurality of pixels 212. In addition, a transistor 300 for controlling the LED chip 200 is provided on each of the plurality of pixels 212.

[0045] The LED chip 200 can emit light at least toward the circuit substrate 100. That is, the light emitted by the LED chip 200 is extracted to the outside through the circuit substrate 100. Furthermore, the LED chip 200 can emit light not only toward the circuit substrate 100 but also toward the side opposite to the circuit substrate 100. In this case, the display device 10 becomes a transparent LED display device capable of double-sided light emission.

[0046] The multiple LED chips 200 may also emit different colors. That is, the display device 10 may also be equipped with a first LED chip 200R, a second LED chip 200G, and a third LED chip 200B, each emitting different colors, in the first pixel 212R, the second pixel 212G, and the third pixel 212B, respectively. For example, the first LED chip 200R is a red LED chip, the second LED chip 200G is a green LED chip, and the third LED chip 200B is a blue LED chip. In this case, the display device 10 can achieve full-color display by controlling the red light from the first LED chip 200R, the green light from the second LED chip 200G, and the blue light from the third LED chip 200B.

[0047] The size of the LED chip 200 is not particularly limited. The LED chip 200 may be appropriately selected in consideration of the size and resolution of the display device 10. For example, if the display device 10 is a small or medium-sized display device, a small LED chip or a micro LED chip may be used.

[0048] In the following description, when the emission colors or pixels are not particularly distinguished, they are referred to as LED chips 200 or pixels 212 .

[0049] The first circuit unit 220L and the second circuit unit 220R include a driving circuit for driving the transistor 300 included in the pixel. The driving circuit is, for example, a scanning line driving circuit (gate driver circuit) or a signal line driving circuit (source driver circuit). Figure 1 In the embodiment, two circuit portions, namely the first circuit portion 220L and the second circuit portion 220R, are provided. However, the number of circuit portions may be one or three or more.

[0050] The connecting portion 230 is connected to the first circuit portion 220L and the second circuit portion 220R via a connecting wiring (not shown). In addition, the connecting portion 230 is connected to an external device via a flexible printed circuit substrate (FPC) or the like. That is, a signal from the external device is transmitted to the first circuit portion 220L and the second circuit portion 220R via the connecting portion 230 to control the transistor 300 of the pixel 212 of the display portion 210. The details of controlling the transistor 300 of the pixel 212 will be described later.

[0051] Figure 2 2 is a schematic cross-sectional view of a pixel 212 of a display device 10 according to an embodiment of the present invention. Specifically, Figure 2 1 is a cross-sectional view showing a structure in which an LED chip 200 is mounted on a pixel 212 of a circuit substrate 100 .

[0052] like Figure 2 As shown, pixel 212 of circuit substrate 100 includes substrate 102, light shielding layer 104, first insulating layer 106, first wiring layer 108, second insulating layer 110, semiconductor layer 112, third insulating layer 114, second wiring layer 116, first planarization layer 118, anode pad 120, and cathode pad 122. LED chip 200 is mounted on anode pad 120 and cathode pad 122 via adhesive layer 400. Furthermore, LED chip 200 is electrically connected to anode pad 120 and cathode pad 122 via adhesive layer 400. In other words, LED chip 200 is flip-chip bonded to circuit substrate 100.

[0053] The substrate 102 can support each layer provided on the substrate 102. The substrate 102 can be any substrate that can transmit the light emitted from the LED chip 200. As the substrate 102, for example, a glass substrate, a quartz substrate, or a sapphire substrate, etc., a light-transmitting rigid substrate can be used. In addition, as the substrate 102, a polyimide resin substrate, an acrylic resin substrate, a silicone resin substrate, or a fluororesin substrate, etc., a light-transmitting flexible substrate can be used. In order to improve the heat resistance of the substrate 102, impurities can also be introduced into the above-mentioned resin substrate. In addition, a substrate having a silicon oxide film or a silicon nitride film formed on the above-mentioned rigid substrate or flexible substrate can also be used as the substrate 102.

[0054] The light shielding layer 104 can reflect or absorb the light emitted from the LED chip 200 or external light. As the material of the light shielding layer 104, for example, aluminum (Al), copper (Cu), titanium (Ti), molybdenum (Mo) or tungsten (W), or their alloys or compounds can be used. In addition, as the material of the light shielding layer 104, for example, a black matrix can also be used. Furthermore, the light shielding layer 104 can not only be a single-layer structure but also a stacked structure. For example, the light shielding layer 104 can be a stacked structure of a red filter, a green filter and a blue filter.

[0055] First insulating layer 106 can insulate light shielding layer 104 by separating it from first wiring layer 108. Furthermore, by providing openings in first insulating layer 106, light shielding layer 104 can be electrically connected to first wiring layer 108, second wiring layer 116, anode pad 120, or cathode pad 122. As the material for first insulating layer 106, for example, a silicon oxide film, a silicon nitride film, or a stacked film thereof can be used.

[0056] The first wiring layer 108, the second insulating layer 110, the semiconductor layer 112, the third insulating layer 114, and the second wiring layer 116 can function as part of the transistor 300. That is, the first wiring layer 108, the second insulating layer 110, the semiconductor layer 112, the third insulating layer 114, and the second wiring layer 116 can function as a gate electrode, a gate insulating film, a channel region, an interlayer insulating film, and a source electrode or a drain electrode, respectively.

[0057] Figure 2 The transistor 300 shown is a bottom-gate transistor. A second insulating layer 110 (gate insulating film) is provided on a first wiring layer 108 (gate electrode). A semiconductor layer 112 (channel region) is provided on the second insulating layer 110 (gate insulating film). A third insulating layer 114 (interlayer insulating film) is provided on the semiconductor layer 112 (channel region). A second wiring layer 116 (source electrode or drain electrode) is provided on the third insulating layer 114 (interlayer insulating film). An opening is provided in the third insulating layer 114 (interlayer insulating film), and the second wiring layer 116 (source electrode or drain electrode) is connected to the semiconductor layer 112 (semiconductor film) through the opening. One side of the second wiring layer 116 connected to the semiconductor layer 112 functions as a source electrode, and the other side of the second wiring layer 116 can function as a drain electrode. The functions of the source electrode and the drain electrode may sometimes be reversed.

[0058] Each of the first wiring layer 108 and the second wiring layer 116 can be made of a metal material. Examples of metal materials include copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten (W), or bismuth (Bi), or alloys or compounds thereof. Furthermore, these metal materials can be stacked to form the first wiring layer 108 or the second wiring layer 116. Furthermore, the first wiring layer 108 or the second wiring layer 116 can function not only as a gate electrode, a source electrode, or a drain electrode of the transistor 300 but also as wiring for connecting multiple transistors 300.

[0059] The second insulating layer 110 and the third insulating layer 114 can each be made of an insulating material. As the insulating material, for example, silicon oxide (SiO x ), silicon oxynitride (SiO x N y ), silicon nitride (SiN x ), silicon oxynitride (SiN x O y ), aluminum oxide (AlO x ), aluminum oxynitride (AlOx N y ), aluminum oxynitride (AlN x O y ), or aluminum nitride (AlN x ) and other inorganic insulators. Here, SiO x N y and AlO x N y It is a silicon compound or aluminum compound containing nitrogen (N) in a smaller amount than oxygen (O). x O y and AlN x O y These are silicon compounds and aluminum compounds containing less oxygen than nitrogen. Furthermore, the second insulating layer 110 and the third insulating layer 114 can each be made of not only the aforementioned inorganic insulating materials but also organic insulating materials. Examples of organic insulating materials include polyimide resins, acrylic resins, epoxy resins, silicone resins, fluororesins, and siloxane resins. The second insulating layer 110 and the third insulating layer 114 can each be made of an inorganic insulating material or an organic insulating material, either singly or in a stack.

[0060] Semiconductor material capable of forming a channel region can be used for the semiconductor layer 112. Examples of semiconductor materials include silicon, oxide semiconductors such as indium gallium zinc oxide (IGZO) or zinc oxide (ZnO), or compound semiconductors such as gallium arsenide (GaAs) or gallium nitride (GaN). When the semiconductor material is silicon, it can be amorphous silicon, polycrystalline silicon, or single crystal silicon.

[0061] exist Figure 2 , one transistor 300 is shown, but a plurality of transistors 300 are provided in the pixel 212. In addition, the transistor 300 is not limited to a bottom-gate transistor. The transistor 300 may also be a top-gate transistor.

[0062] The first planarization layer 118 can planarize the unevenness of the transistor 300. As a material of the first planarization layer 118, for example, acrylic resin or polyimide resin can be used.

[0063] The anode pad 120 and the cathode pad 122 can function as electrode pads electrically connected to the LED chip 200. Figure 2 In the embodiment, the anode pad 120 is electrically connected to the transistor 300 , but the cathode pad 122 may also be electrically connected to the transistor 300 .

[0064] Anode pad 120 and cathode pad 122 preferably have a stacked structure. Specifically, anode pad 120 includes a first electrode layer 120-1 and a second electrode layer 120-2, and cathode pad 122 includes a third electrode layer 122-1 and a fourth electrode layer 122-2. The stacked structure of anode pad 120 and cathode pad 122 is not limited to two layers and may also include three or more layers.

[0065] Anode pad 120 and cathode pad 122 may be made of, for example, aluminum (Al), copper (Cu), titanium (Ti), molybdenum (Mo), tungsten (W), or alloys or compounds thereof. Anode pad 120 and cathode pad 122 may be made of, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0066] When the anode pad 120 and the cathode pad 122 have a stacked structure, it is preferable to respectively provide a second electrode layer 120-2 and a fourth electrode layer 122-2 made of a transparent conductive material on the first electrode layer 120-1 and the third electrode layer 122-1 made of a metal material. By covering the surface of the metal material with the transparent conductive material, the surface of the metal material can be protected.

[0067] The adhesive layer 400 can electrically connect and bond the circuit board 100 and the LED chip 200. For example, silver paste or solder can be used as the adhesive layer 400. Alternatively, an anisotropic conductive film (ACF) can be used as the adhesive layer 400.

[0068] Figure 2 The LED chip 200 is mounted on the circuit substrate 100 using flip chip bonding via the adhesive layer 400 , but the mounting of the LED chip 200 is not limited thereto. The LED chip 200 may also be mounted on the circuit substrate 100 using wire bonding.

[0069] [2. LED chip structure]

[0070] In the display device 10, an LED chip 200 having a horizontal LED structure (horizontal electrode structure) is used. Figure 3 The LED chip 200 having a horizontal LED structure will be described.

[0071] Figure 3 1 is a schematic cross-sectional view of an LED chip 200 mounted on a display device 10 according to an embodiment of the present invention.

[0072] like Figure 3As shown, the LED chip 200 includes a substrate 201 , an n-type semiconductor layer 202 , a light-emitting layer 203 , a p-type semiconductor layer 204 , a p-type electrode 205 , an n-type electrode 206 , an anode bump 207 and a cathode bump 208 .

[0073] The substrate 201 can support each layer provided thereon. Furthermore, the substrate 201 is preferably a substrate capable of crystallizing the n-type semiconductor layer 202, the light-emitting layer 203, and the p-type semiconductor layer 204. For example, a sapphire substrate, a silicon carbide substrate, or a gallium nitride substrate can be used as the substrate 201.

[0074] If LED chip 200 is a red LED chip, the materials constituting light-emitting layer 203 include aluminum, gallium, indium, and phosphorus. The composition ratio of aluminum, gallium, and indium is typically, but not limited to, 0.225:0.275:0.5. Furthermore, n-type semiconductor layer 202 and p-type semiconductor layer are each made of aluminum indium phosphide.

[0075] If LED chip 200 is a green LED chip, the materials constituting light-emitting layer 203 include indium, gallium, and nitrogen. The composition ratio of indium to gallium is typically, but not limited to, 0.44:0.55. Furthermore, both n-type semiconductor layer 202 and p-type semiconductor layer are gallium nitride.

[0076] If LED chip 200 is a blue LED chip, the materials constituting light-emitting layer 203 include indium, gallium, and nitrogen. The composition ratio of indium to gallium is typically, but not limited to, 0.2:0.8. Furthermore, both n-type semiconductor layer 202 and p-type semiconductor layer are gallium nitride.

[0077] In any of the red LED chip, the green LED chip, and the blue LED chip, aluminum can be used for the p-type electrode 205 and the n-type electrode 206 , but the present invention is not limited thereto.

[0078] LED chip 200 is formed by crystal-growing n-type semiconductor layer 202, light-emitting layer 203 and p-type semiconductor layer 204 on substrate 201, and then forming p-type electrode 205 and n-type electrode 206. Substrate 201 is then diced to separate individual LED chips 200.

[0079] The maximum emission wavelengths of the red LED chip, the green LED chip, and the blue LED chip are typically 645 nm, 530 nm, and 450 nm, respectively.

[0080] The anode bump 207 and the cathode bump 208 are electrodes for connecting to the circuit substrate 100 and can adjust the height of the LED chip 200. That is, when the height of the surface of the p-type electrode 205 is different from the height of the surface of the n-type electrode 206, the anode bump 207 and the cathode bump 208 can be used to adjust the height of the LED chip 200. The anode bump 207 and the cathode bump 208 can be formed by plating, sputtering, evaporation, or printing. When plating is used to form the anode bump 207 and the cathode bump 208, gold can be used as the material of the anode bump 207 and the cathode bump 208, but it is not limited to this.

[0081] LED chip 200 is formed by crystallizing an n-type semiconductor layer 202, a light-emitting layer 203, and a p-type semiconductor layer 204 on a substrate 201. A p-type electrode 205 and an n-type electrode 206 are then formed. Next, anode bumps 207 and cathode bumps 208 are formed on the p-type electrode 205 and n-type electrode 206, respectively. Finally, substrate 201 is diced to separate the individual LED chips 200.

[0082] The LED chip 200 is not limited to Figure 2 For example, the p-type electrode 205 and the n-type electrode 206 may be omitted, and the anode bump 207 and the cathode bump 208 may be formed on each of the p-type semiconductor layer 204 and the n-type semiconductor layer 202 .

[0083] Furthermore, the LED chip 200 is not limited in size, and for example, a small LED chip or a micro LED chip may be used.

[0084] [3. Pixel Configuration]

[0085] The LED chip 200 is controlled using a plurality of transistors 300 included in the pixel 212. Therefore, in the following, referring to Figure 4 The pixel circuit that drives the LED chip 200 will be described.

[0086] Figure 4 1 is a circuit diagram showing a circuit (pixel circuit) for driving the LED chip 200 in the pixel 212 of the display device 10 according to one embodiment of the present invention.

[0087] like Figure 4As shown, the pixel circuit of the pixel 212 includes an LED chip 200, a first transistor 300-1, a second transistor 300-2, a third transistor 300-3, a fourth transistor 300-4, a fifth transistor 300-5, and a first capacitor 310. In addition, it includes a scan line 241, a signal line 242, a light emission control scan line 243, a current supply line 244, an initialization scan line 245, an initialization line 246, a reset scan line 247, a reset line 248, and a cathode wiring 249 (Cat).

[0088] The first transistor 300 - 1 is a light emission control transistor, which is turned on and off by the light emission control scanning line 243 to select whether current flows to the LED chip 200 and the fifth transistor 300 - 5 .

[0089] The second transistor 300 - 2 is a selection transistor and is turned on and off at the scan line 241 , and applies a voltage supplied from the signal line 242 to the gate of the fifth transistor 300 - 5 .

[0090] The third transistor 300 - 3 is an initialization transistor, which is turned on and off by the initialization scanning line 245 and fixes the gate of the fifth transistor 300 - 5 to a predetermined potential using a voltage supplied from the initialization line 246 .

[0091] The fourth transistor 300 - 4 is a reset transistor that is turned on and off by the reset scan line 247 and applies a reverse bias voltage provided by the reset line 248 to the LED chip 200 .

[0092] The fifth transistor 300 - 5 is a driving transistor. As described above, the fifth transistor 300 - 5 determines the gate potential based on the operation of the second transistor 300 - 2 or the third transistor 300 - 3 , and supplies a current having a value determined by the gate potential to the LED chip 200 from the current supply line 244 .

[0093] Here, refer to Figure 5 ,right Figure 4 An example of the layout of the pixel circuit shown in FIG.

[0094] Figure 5 2 is a schematic top view of a pixel 212 of a display device 10 according to an embodiment of the present invention. Specifically, Figure 5 The structure of the circuit substrate 100 side of the pixel 212 is shown, but the anode pad 120 and the cathode pad 122 are omitted to facilitate understanding of the connection relationship between the transistors 300. In addition, in the connection of each layer, the overlapping part of each layer can also be connected through the opening. Figure 5In the figure, the opening is represented by a rectangle, but the shape of the opening may be a circle or an ellipse.

[0095] like Figure 5 As shown, the pixel 212 includes a first transistor 300-1, a second transistor 300-2, a third transistor 300-3, a fourth transistor 300-4, a fifth transistor 300-5, and a first capacitor 310. In addition, it includes a scan line 241, a signal line 242, a light emission control scan line 243, a current supply line 244, an initialization scan line 245, an initialization line 246, a reset scan line 247, and a reset line 248.

[0096] Each of the first transistor 300-1, the second transistor 300-2, the third transistor 300-3, the fourth transistor 300-4, and the fifth transistor 300-5 includes a first wiring layer 108 serving as a gate electrode and a semiconductor layer 112 forming a channel region. Furthermore, the first wiring layer 108 (dashed line portion), which functions as the gate electrode of the fifth transistor 300-5, is provided below and overlaps with the second wiring layer 116.

[0097] The first capacitor 310 includes the first wiring layer 108, which functions as a capacitor electrode, and the second wiring layer 116. Furthermore, the first wiring layer 108 (dashed line portion), which functions as a capacitor electrode of the first capacitor 310, is also provided below and overlaps with the second wiring layer 116.

[0098] Scan lines 241, signal lines 242, emission control scan lines 243, current supply lines 244, initialization scan lines 245, initialization lines 246, reset scan lines 247, and reset lines 248 are each formed primarily using the second wiring layer 116. The second wiring layer 116 is in contact with the semiconductor layers 112 that overlap with each other via openings.

[0099] The current supply line 244 carries current to control the brightness of the LED chip 200. Therefore, the width of the second wiring layer 116 forming the current supply line 244 is preferably greater than the width of other wiring. The emission control scan line 243 can be shared between adjacent pixels. In this case, the width of the second wiring layer 116 forming the emission control scan line 243 is preferably greater than the width of the second wiring layer 116 forming the current supply line 244.

[0100] like Figure 5 As shown in the third transistor 300-3, a portion of the second wiring layer 116 constituting the initialization line 246 may be provided with an increased width, and an opening for connecting the wiring layer may be formed in the portion.

[0101] [4. Structure of the light-transmitting area]

[0102] like Figure 5 As shown, the pixel 212 of the circuit substrate 100 includes a large number of electrodes and wirings. The electrodes and wirings are mostly formed of metal materials, so the electrodes and wirings do not transmit the light emitted from the LED chip. Therefore, in order to extract the light emitted by the LED chip 200 from the circuit substrate 100 side, it is necessary to provide an area (light transmission area 500) in the pixel 212 that can transmit the light emitted from the LED chip 200 (for example, visible light). Therefore, referring to 6A to 6D , the light-transmitting region 500 in the circuit substrate 100 of the display device 10 will be described.

[0103] 6A to 6D This is a schematic plan view showing the positional relationship between the anode pad 120 and the cathode pad 122 of the circuit substrate 100 and the LED chip 200 in the display device 10 according to one embodiment of the present invention.

[0104] exist Figure 6A In FIG, the structure of the circuit substrate 100 side, namely, the anode pad 120 and the cathode pad 122, are indicated by solid lines, and the LED chip 200 and the structure of the LED chip 200, namely, the p-type electrode 205 and the n-type electrode 206, are indicated by dotted lines. Figure 6A In the structure shown, anode pad 120 is electrically connected to p-type electrode 205, and cathode pad 122 is electrically connected to n-type electrode 206. If anode pad 120 functions as a cathode pad and cathode pad 122 functions as an anode pad, the electrical connections of LED chip 200 can be reversed.

[0105] Figure 6B This shows a structure in which there is no electrode or wiring between the anode pad 120 and the cathode pad 122 when looking down at the circuit substrate 100. The light emitted from the LED chip 200 is blocked by the anode pad 120 and the cathode pad 122, but the area between the anode pad 120 and the cathode pad 122 can be transmitted. In reality, since there is a space between the circuit substrate 100 and the LED chip 200, it is assumed that the light emitted from the LED chip 200 also transmits the area around the anode pad 120 or the cathode pad 122. However, in this specification, the light emitted from the LED chip 200 is not transmitted. Figure 6B As shown, a region overlapping with the LED chip 200 , between the anode pad 120 and the cathode pad 122 , and transmitting light emitted from the LED chip 200 is defined as a light-transmitting region 500 .

[0106] Figure 6C This is an example of a case where the shape of the anode pad 120a is different from the shape of the cathode pad 122a. There is no electrode or wiring between the anode pad 120a and the cathode pad 122a. In this case, Figure 6CAs shown, a region overlapping LED chip 200, between anode pad 120a and cathode pad 122a, and transmitting light emitted from LED chip 200 is defined as light-transmitting region 500a. Specifically, light-transmitting region 500a is a region enclosed by two opposing sides of anode pad 120a and cathode pad 122a and two lines connecting the two sides.

[0107] Figure 6D This is an example of a case where the anode pad 120b and the cathode pad 122b have a curved shape. There is no electrode or wiring between the anode pad 120b and the cathode pad 122b. In this case, Figure 6D As shown, the region overlapping LED chip 200, between anode pad 120b and cathode pad 122b, and transmitting light emitted from LED chip 200 is defined as light-transmitting region 500b. Specifically, light-transmitting region 500b is the region enclosed by the curved line of anode pad 120b, the curved line of cathode pad 122b, and two tangent lines to anode pad 120b and cathode pad 122b.

[0108] In fact, if Figure 5 As shown, the pixel 212 of the circuit substrate 100 includes a large number of electrodes and wirings. In the display device 10 of this embodiment, by using these electrodes or wirings as a light shielding film, the area of the light-transmitting region 500 is adjusted, thereby adjusting the brightness of the light transmitted through the circuit substrate 100. Therefore, in the following, referring to 7A to 7D , the adjustment of the area of the light-transmitting region 500 is described.

[0109] 7A to 7D 1 is a schematic plan view showing a light-transmitting region 500 whose area is adjusted in the display device 10 according to one embodiment of the present invention.

[0110] exist Figure 7A In the embodiment, anode pad 120c includes a first electrode layer 120c-1 and a second electrode layer 120c-2, and cathode pad 122c includes a third electrode layer 122c-1 and a fourth electrode layer 122c-2. First electrode layer 120c-1 includes a portion (protruding portion) that is larger than second electrode layer 120c-2 and protrudes further toward cathode pad 122c than the end of second electrode layer 120c-2.

[0111] The area of the light-transmitting region 500c can be adjusted by the protruding portion of the first electrode layer 120c-1. That is, by increasing the protruding portion of the first electrode layer 120c-1, the area of the light-transmitting region 500c can be reduced, and by reducing the protruding portion of the first electrode layer 120c-1, the area of the light-transmitting region 500c can be increased. Alternatively, the area of the light-transmitting region 500c can be adjusted by the cathode pad 122c rather than the anode pad 120c. That is, the third electrode layer 122c-1 can include a portion (protruding portion) that is larger than the fourth electrode layer 122c-2 and protrudes further toward the anode pad 120c than the end of the fourth electrode layer 122c-2.

[0112] exist Figure 7B In the embodiment, anode pad 120d includes a first electrode layer 120d-1 and a second electrode layer 120d-2, and cathode pad 122d includes a third electrode layer 122d-1 and a fourth electrode layer 122d-2. First electrode layer 120d-1 includes a portion (protruding portion) that is larger than second electrode layer 120d-2 and protrudes further toward cathode pad 122d than the end of second electrode layer 120d-2. Furthermore, the protruding portion of first electrode layer 120d-1 is formed into a concave-convex shape.

[0113] The area of the light-transmitting region 500d can be adjusted by changing the size of the convex and concave portions formed in the protruding portion of the first electrode layer 120d-1. Specifically, by increasing the convex portion of the protruding portion of the first electrode layer 120d-1, the area of the light-transmitting region 500d can be reduced, while by increasing the concave portion of the protruding portion of the first electrode layer 120d-1, the area of the light-transmitting region 500d can be increased.

[0114] exist Figure 7C In the embodiment, a light-shielding layer 104e is included between the anode pad 120e and the cathode pad 122e. Since the light-shielding layer 104e is formed of a metal material, light from the LED chip 200 does not pass through the light-shielding layer 104e. Therefore, the area of the light-transmitting region 500e can be adjusted according to the size of the light-shielding layer 104e. In other words, by increasing the width or length of the light-shielding layer 104e or increasing the number of light-shielding layers 104e, the area of the light-transmitting region 500e can be reduced. Conversely, by reducing the width or length of the light-shielding layer 104e or reducing the number of light-shielding layers 104e, the area of the light-transmitting region 500e can be increased.

[0115] In addition, the light shielding layer 104e provided in the light transmission area 500e is in a floating state and is not electrically connected to the LED chip 200 and the pixel circuit of the pixel 212, and can also be called a dummy pattern provided in the light transmission area 500e of the LED chip 200. Figure 2As shown, a light shielding layer 104e serving as a dummy pattern is provided between the first wiring layer 108 and the substrate 102. Furthermore, the light shielding layer 104e serving as a dummy pattern is a layer separate from any of the first wiring layer 108, the second wiring layer 116, and the semiconductor layer 112 that form the pixel circuit. Therefore, by forming the light shielding layer 104e serving as a dummy pattern, the likelihood of short circuits between wirings within the pixel circuit is reduced. Furthermore, the light shielding layer 104e, provided independently of other layers, can be formed into various shapes and patterns, providing a high degree of freedom in the shape of the light shielding layer 104e.

[0116] In addition, the light shielding layer 104e may be formed only in the light transmitting region 500e, only in a region that does not overlap with the pixel circuit other than the LED chip 200, or may overlap with a portion of the pixel circuit.

[0117] exist Figure 7D In the embodiment, a second wiring layer 116f is included between the anode pad 120f and the cathode pad 122f. Since the second wiring layer 116f is formed of a metal material, light emitted from the LED chip 200 does not pass through the second wiring layer 116f. Therefore, the area of the light-transmitting region 500f can be adjusted according to the size of the second wiring layer 116f. In other words, by increasing the width or length of the second wiring layer 116f, or increasing the number of second wiring layers 116f, the area of the light-transmitting region 500f can be reduced. Conversely, by reducing the width or length of the second wiring layer 116f, or reducing the number of second wiring layers 116f, the area of the light-transmitting region 500f can be increased.

[0118] When adjusting the area of the light-transmitting region 500f, the first wiring layer 108f may be used instead of the second wiring layer 116f. The second wiring layer 116f or the first wiring layer 108f provided in the light-transmitting region 500f may be referred to as a dummy pattern that is not connected to the LED chip 200 or the pixel circuit of the pixel 212 and is in a floating state.

[0119] Alternatively, second wiring layer 116f or first wiring layer 108f serving as a dummy pattern may be a wiring layer extended from second wiring layer 116 or first wiring layer 108 forming the pixel circuit toward light-transmitting region 500f in order to adjust the area of light-transmitting region 500f. Alternatively, second wiring layer 116f or first wiring layer 108f serving as a dummy pattern may be adjusted by increasing or decreasing a portion of the wiring width of second wiring layer 116 or first wiring layer 108 forming the pixel circuit.

[0120] In the display device 10 of this embodiment, the light emitted from the LED chip 200 can be extracted from the circuit substrate 100 side. That is, the light emitted from the light-transmitting region 500 of the circuit substrate 100 is emitted from the circuit substrate 100 side. In this case, since the area of the light-transmitting region 500 of each of the plurality of pixels is adjusted to be constant, it is possible to obtain light of uniform brightness from each pixel. Therefore, in the following, referring to Figures 8A to 8C , the adjustment of the area of the light-transmitting region 500 in a plurality of pixels is described.

[0121] Figures 8A to 8C 1 is a schematic top view showing three pixels 212 included in the display unit 210 of the circuit substrate 100 in the display device 10 according to one embodiment of the present invention. The display unit 210 includes a first pixel 212R, a second pixel 212G, and a third pixel 212B as the three pixels 212. Figures 8A to 8C In the example, the opening connecting the lower layer and the upper layer is omitted. Figures 8A to 8C The opening can be appropriately provided at a portion where the end of the lower layer overlaps with the end of the upper layer, a portion where the end of the lower layer overlaps with the upper layer, or a portion where the end of the lower layer overlaps with the end of the upper layer.

[0122] like Figure 8A As shown, first pixel 212R, second pixel 212G, and third pixel 212B each include an anode pad 120 and a cathode pad 122. Anode pad 120 includes a first electrode layer 120-1 and a second electrode layer 120-2. Furthermore, cathode pad 122 includes a third electrode layer 122-1 and a fourth electrode layer 122-2. Here, the first electrode layer 120-1 and the third electrode layer 122-1 are formed of a metal material that does not transmit visible light, while the second electrode layer 120-2 and the fourth electrode layer 122-2 are formed of a transparent conductive material that transmits visible light. Furthermore, the light shielding layer 104, the first wiring layer 108, and the second wiring layer 116 are formed of a metal material that does not transmit visible light.

[0123] First electrode layer 120-1 includes a portion (protruding portion) that is larger than second electrode layer 120-2 and protrudes further toward cathode pad 122 than the end of second electrode layer 120-2. Therefore, first pixel 212R includes a first light-transmitting region 500R, the area of which is adjusted by first electrode layer 120-1, between anode pad 120 and cathode pad 122. Similarly, second pixel 212G includes second light-transmitting region 500G, and third pixel 212B includes third light-transmitting region 500B.

[0124] The size of the protrusion of the first electrode layer 120-1 may be different between the first pixel 212R, the second pixel 212G, and the third pixel 212B. By adjusting the size of the protrusion, the area of the first light-transmitting region 500R, the second light-transmitting region 500G, and the third light-transmitting region 500B can be adjusted.

[0125] The first pixel 212R includes a light shielding layer 104 and a second wiring layer 116 between the first electrode layer 120-1 and the cathode pad 122. Therefore, light emitted from the first LED chip 200R mounted in the first pixel 212R is shielded by the light shielding layer 104 and the second wiring layer 116. Therefore, the first light-transmitting region 500R is an area located between the anode pad 120 (specifically, the first electrode layer 120-1) and the cathode pad 122 and overlapping the first LED chip 200R, excluding the light shielding layer 104 and the second wiring layer 116. In other words, the first light-transmitting region 500R includes multiple areas separated by the light shielding layer 104 and the second wiring layer 116.

[0126] The second pixel 212G includes the first wiring layer 108 and the second wiring layer 116 between the first electrode layer 120-1 and the cathode pad 122. Therefore, light emitted from the second LED chip 200G mounted in the second pixel 212G is shielded by the first wiring layer 108 and the second wiring layer 116. Therefore, the second light-transmitting region 500G is a region located between the anode pad 120 (specifically, the first electrode layer 120-1) and the cathode pad 122 and overlapping the second LED chip 200G, excluding the first wiring layer 108 and the second wiring layer 116. In other words, the second light-transmitting region 500G includes multiple regions separated by the first wiring layer 108 and the second wiring layer 116.

[0127] The third pixel 212B includes the first wiring layer 108 and the second wiring layer 116 between the first electrode layer 120-1 and the cathode pad 122. Therefore, light emitted from the third LED chip 200B mounted in the third pixel 212B is shielded by the first wiring layer 108 and the second wiring layer 116. Therefore, the third light-transmitting region 500B is a region located between the anode pad 120 (specifically, the first electrode layer 120-1) and the cathode pad 122 and overlapping the third LED chip 200B, excluding the first wiring layer 108 and the second wiring layer 116. In other words, the third light-transmitting region 500B includes multiple regions separated by the second wiring layer 116.

[0128] In order to make the brightness of light transmitted through the first light-transmitting region 500R and the brightness of light transmitted through the second light-transmitting region 500G consistent, the first area of the first light-transmitting region 500R and the second area of the second light-transmitting region 500G preferably have a first ratio of first area:second area = 1:0.8 to 1.2 (0.8 or more and 1.2 or less). A more preferred first ratio is first area:second area = 1:0.9 to 1.1 (0.9 or more and 1.1 or less). Furthermore, in order to make the brightness of light transmitted through the first light-transmitting region 500R and the brightness of light transmitted through the third light-transmitting region 500B consistent, the first area of the first light-transmitting region 500R and the third area of the third light-transmitting region 500B preferably have a second ratio of first area:third area = 1:0.8 to 1.2 (0.8 or more and 1.2 or less). A more preferred second ratio is first area:third area = 1:0.9 to 1.1 (0.9 or more and 1.1 or less). If the first ratio and the second ratio are within the above range, the luminance of light emitted from each pixel 212 is constant, and therefore, the display device 10 can perform display with suppressed luminance variations.

[0129] The first area, the second area, and the third area can be adjusted not only by changing the size of the first electrode layer 120 - 1 , but also by changing the width or number of the light shielding layer 104 , the first wiring layer 108 , and the second wiring layer 116 .

[0130] Figure 8B This is to visualize the structure below the anode pad 120 and the cathode pad 122. Figure 8A The cathode line Cat is omitted in the figure, and the anode pad 120 and the cathode pad 122 are made transparent. Figure 8C is to visualize the position of transistor 300, and Figure 8B FIG. 1 shows a diagram in which the second wiring layer 116 provided between the anode pad 120 and the cathode pad 122 is made transparent.

[0131] like Figure 8B as well as Figure 8C As shown, the first pixel 212R, the second pixel 212G and the third pixel 212B each include a transistor 300 (see Figure 2 as well as Figure 5 ) is a bottom-gate transistor. By providing a light shielding layer 104 below the first wiring layer 108 that functions as the gate electrode of the transistor 300, the first area, the second area, or the third area can be adjusted regardless of the configuration of the transistor 300. Figure 8B as well as Figure 8C Like the first pixel 212R, the fifth transistor 300-5 and the first capacitor 310 (see FIG. Figure 5), the light shielding layer 104 may be provided overlapping with the fifth transistor 300-5 and the first capacitor 310. In addition, the potential of the light shielding layer 104 may be in a floating state.

[0132] In the case where the transistor 300 is a bottom-gate transistor, as shown in FIG. Figures 8A to 8C As shown, the semiconductor layer 112 is preferably disposed below the first electrode layer 120-1 or the third electrode layer 122-1. Since the first electrode layer 120-1 or the third electrode layer 122-1 shields the light emitted from the LED chip 200, the driving of the transistor 300 is stable.

[0133] exist Figures 8A to 8C In FIG, the scan line and the signal line extend in a direction from the first pixel 212R toward the second pixel 212G, and the scan line extends in a direction from the second pixel 212G toward the third pixel. Figure 8C In the first transistor 300 - 1 of the illustrated first pixel 212R, a wiring branched from a scanning line extending in a direction from the first pixel 212R toward the second pixel 212G can be used as a gate electrode.

[0134] like Figure 8A As shown, the third electrode layer 122-1 of the cathode pad 122 may be provided as a wiring shared by the first pixel 212R, the second pixel 212G, and the third pixel 212B. In the following, for convenience, wiring of the same layer as the third electrode layer 122-1 may be referred to as wiring 122-1.

[0135] The wiring 122-1 may also be arranged along the current supply line 244 (see Figure 5 ) is set. For example, the wiring 122-1 can also be equivalent to Figure 4 In the display unit 210, the wiring 122-1 is connected to the current supply line 244 ( Figure 5 、 Figure 8B ) overlaps, extends in parallel with the current supply line 244, and is led out to the outside of the display unit 210. Furthermore, the wiring 122-1 (cathode line Cat) may be connected to the cathode pad 122 of the third pixel 212B and formed in a lattice structure in the display unit 210. Figure 8A , the wiring 122-1 (cathode line Cat) is formed along the current supply line 244 of the first pixel 212R and the second pixel 212G, and crosses the current supply line 244 of the third pixel 212B but does not extend along the current supply line 244 of the third pixel 212B ( Figure 8BHowever, the wiring 122-1 (cathode line Cat) may be extended along the current supply line 244 of the third pixel 212B.

[0136] exist Figure 8B and Figure 8C In FIG, the first pixel 212R, the second pixel 212G and the third pixel 212B are represented by dotted lines. In addition, the anode pad 120 and the cathode pad 122 of each of the first pixel 212R, the second pixel 212G and the third pixel 212B are also represented by dotted lines. Figure 8B and Figure 8C As shown, anode pad 120 and cathode pad 122 are provided in first pixel 212R, and the same applies to second pixel 212G and third pixel 212B.

[0137] Figure 5 Equivalent to Figure 8B as well as Figure 8C The layout of the first pixel 212R shown in FIG. 1 is repeated and the description thereof is omitted. Figure 8C As shown, the first transistor 300-1 and the fifth transistor 300-5 of the first pixel 212R overlap with the cathode pad 122. Similarly, the second transistor 300-2, the third transistor 300-3, and the fourth transistor 300-4 overlap with the anode pad 120. That is, all five transistors 300 provided in the pixel circuit are covered by the anode pad 120 or the cathode pad 122. Through this structure, the light extracted from the circuit substrate 100 side of the LED chip 200 is shielded by the anode pad 120 and the cathode pad 122, so that the transistors 300 constituting the pixel circuit are not transmitted. Therefore, the degradation of transistor characteristics caused by light exposure can be suppressed. In addition, except for the area where the LED chip 200 of the circuit substrate 100 is mounted, only the wiring constituting the pixel circuit is formed, so the layout has a high degree of freedom and does not impair the transparency of the circuit substrate 100 when viewed from the front side or the back side (circuit substrate side) of the transparent LED display device.

[0138] Here, a transparent LED display device is described. The transparent LED display device is a display device that can visually confirm the background on the back side when viewed from the front side, and can visually confirm the background on the front side when viewed from the back side. In the transparent LED display device, the transparency of the circuit substrate 100 becomes important. Here, the front side refers to, for example, the LED chip 200 side, and the back side refers to, for example, the circuit substrate 100 side. Figures 8A to 8CAs shown, in addition to forming all transistors 300 constituting the pixel circuit of the pixel 212 so as to overlap with the anode pad 120 or the cathode pad 122 of the circuit substrate 100, the transparency of the circuit substrate 100 as a whole can be improved by converging various wirings constituting the pixel circuit and increasing the area of the transparent region. Figure 8B as well as Figure 8C As shown, the scan line 241, the initialization scan line 245, the reset scan line 247, and the light emission control scan line 243 extend parallel to the first direction X and are arranged at regular intervals in the second direction Y. Similarly, the reset line 248, the signal line 242, the initialization line 246, and the current supply line 244 extend parallel to the second direction Y and are arranged at regular intervals in the first direction X. Figure 8A The wiring 122-1 (cathode line Cat) shown in FIG. 1 extends in the first direction X and the second direction Y. Figure 8B as well as Figure 8C As shown, the first pixel 212R is set at a position separated from the scan line 241, the initialization scan line 245, the reset scan line 247 and the light emission control scan line 243 extending along the first direction X, so it can be connected to the four scan lines by using the routing wiring extending toward the second direction Y.

[0139] In the first pixel 212R, the second transistor 300-2, the third transistor 300-3, and the fourth transistor 300-4 have a constant interval along the second direction Y and are arranged in this order. The same is true for the second pixel 212G and the third pixel 212B. The second transistor 300-2, the third transistor 300-3, and the fourth transistor 300-4 of each pixel 212 are all located below the anode pad 120 of each pixel 212 and are shielded from light by the anode pad 120. In other words, the second transistor 300-2, the third transistor 300-3, and the fourth transistor 300-4 are all formed at a position closer to the inside than the outer periphery of the anode pad 120 and do not protrude from the anode pad 120.

[0140] In the first pixel 212R, the first transistor 300-1 and the fifth transistor 300-5 are arranged in this order with a constant interval in the first direction X. The same is true for the second pixel 212G. On the other hand, in the third pixel, although the first transistor 300-1 and the fifth transistor 300-5 are arranged in a constant interval in the first direction X, the order of arrangement is opposite to that of the first pixel 212R and the second pixel 212G. That is, in the third pixel, the fifth transistor 300-5 and the first transistor 300-1 are arranged in the first direction X in sequence. However, 300-1 and 300-5 of each pixel 212 are located below the cathode pad 122 of each pixel 212 and are shielded from light by the cathode pad 122. In other words, the first transistor 300-1 and the fifth transistor 300-5 are both formed in a position closer to the inside than the outer periphery of the cathode pad 122 and are not exposed from the cathode pad 122.

[0141] Here, the reset line 248, the first pixel signal line 242(R), the second pixel signal line 242(G), and the initialization line 246 overlapping the first pixel 212R and the second pixel 212G are defined as a first signal line group, and the reset line 248, the third pixel signal line 242(B), and the initialization line 246 overlapping the third pixel 212B are defined as a second signal line group. The current supply line 244 is located between the first and second signal line groups. The current supply line 244 connected to the first and second pixels 212R, 212G is formed to be thicker (greater in width) than the current supply line 244 connected to the third pixel 212B. By configuring the current supply line 244 in this manner, for example, if the characteristics (luminous efficiency) of the LED chips 200 mounted in the first pixel 212R and the second pixel 212G differ from the characteristics (luminous efficiency) of the LED chip 200 mounted in the third pixel 212B, the difference in characteristics between the LED chips 200 having different characteristics can be reduced by reducing the resistance value of the current supply line 244 on the side of the LED chip 200 with the lower characteristics. Furthermore, the current supply line 244 connected to the first pixel 212R and the second pixel 212G and the current supply line 244 connected to the third pixel 212B are connected to each other via a connecting portion 244'. By arranging the current supply line 244 between the first signal line group and the second signal line group, the wiring layout can be designed efficiently.

[0142] For example, in each of the first pixel 212R, the second pixel 212G, and the third pixel 212B, a red LED chip can be mounted as the first LED chip 200R, a green LED chip can be mounted as the second LED chip 200G, and a blue LED chip can be mounted as the third LED chip 200B. In this case, red light is emitted from the first pixel 212R, green light is emitted from the second pixel 212G, and blue light is emitted from the third pixel 212B. According to the display device 10 of this embodiment, the area ratios of the first light-transmitting region 500R, the second light-transmitting region 500G, and the third light-transmitting region 500B, which transmit red light, green light, and blue light, respectively, are adjusted. This ensures that the luminance of the red, green, and blue light emitted from the circuit substrate 100 side is constant. Consequently, the color balance of the display device 10 is adjusted, enabling display with suppressed brightness variations. Furthermore, if the display device 10 employs dual-sided illumination, it is possible to achieve a display with minimal difference in display quality between the two sides.

[0143] <Second embodiment>

[0144] Reference Figure 9 , the arrangement of pixels 212 in the display unit 210 of the display device 10 according to one embodiment of the present invention will be described.

[0145] Figure 9 1 is a schematic top view showing the arrangement of pixels 212 in the display unit 210 of the display device 10 according to one embodiment of the present invention. Specifically, Figure 9 Pixels 212 that form part of the display unit 210 of the display device 10 are shown.

[0146] like Figure 9 As shown, the display portion 210 includes a first pixel 212R, a second pixel 212G, and a third pixel 212B. A red LED chip, a green LED chip, and a blue LED chip are mounted on the first pixel 212R, the second pixel 212G, and the third pixel 212B, respectively. Red light is emitted from the first pixel 212R, green light is emitted from the second pixel 212G, and blue light is emitted from the third pixel 212B.

[0147] The first pixel 212R, the second pixel 212G, and the third pixel 212B are each rectangular with a long side and a short side. The first pixel 212R is arranged with the long side of the rectangle in the X direction and the short side of the rectangle in the Y direction. The second pixel 212G is arranged with the long side of the rectangle in the X direction and the short side of the rectangle in the Y direction. The third pixel 212B is arranged with the long side of the rectangle in the X direction and the short side of the rectangle in the Y direction. In the case where the display portion 210 is rectangular, the X and Y directions are, for example, such that the X direction is the long side of the rectangle and the Y direction is the short side of the rectangle.

[0148] The shape of the pixel 212 is not limited to a rectangle. The shape of the pixel 212 may also be, for example, an ellipse. When the pixel 212 is a shape other than a rectangle, the long side and short side may be the longest side or major axis and the shortest side or minor axis, respectively.

[0149] The display portion 210 has first pixels 212R and second pixels 212G alternately arranged in the Y direction. In addition, the display portion 210 has first pixels 212R or second pixels 212G and third pixels 212B alternately arranged in the X direction.

[0150] Alternatively, the display unit 210 may repeatedly arrange a first unit 214 consisting of one first pixel 212R, one second pixel 212G, and one third pixel 212B in the X and Y directions. Within the first unit 214, the first pixel 212R or the second pixel 212G is arranged adjacent to each other in the Y direction, and the first pixel 212R or the second pixel 212G and the third pixel 212B are arranged adjacent to each other in the X direction. Furthermore, the third pixel 212B is arranged closer to the second pixel 212G than the first pixel 212R. Furthermore, the third pixel 212B may be arranged closer to the first pixel 212R than the second pixel 212G, or may be arranged between the first pixel 212R and the second pixel 212G.

[0151] The display unit 210 performs full-light display (full white display), and thus can be confirmed to have good display quality.

[0152] <Variation 1>

[0153] Reference Figure 10 , the arrangement of pixels 212 in the display unit 210a which is different from the display unit 210 is described.

[0154] Figure 10 1 is a schematic top view showing the arrangement of pixels 212 in a display unit 210a of a display device 10 according to an embodiment of the present invention. Specifically, Figure 10Pixels 212 are shown as part of the display unit 210a of the display device 10. In this variation, red light is emitted from the first pixel 212R, green light is emitted from the second pixel 212G, and blue light is emitted from the third pixel 212B. In the description of the display unit 210a of this variation, descriptions of the same structures as those of the display unit 210 are omitted.

[0155] The display unit 210a includes a first unit 214 and a second unit 215. The second unit 215 is formed by swapping the positions of the first pixel 212R and the second pixel 212G within the first unit 214. The display unit 210a has the first unit 214 and the second unit 215 alternately arranged in the X direction. Furthermore, the display unit 210a has the first unit 214 alternately arranged in the Y direction, and the second unit 215 alternately arranged adjacent to the first unit 214.

[0156] When the display portion 210 a is fully lit (fully white), the screen appears rough, but no roughness is observed at the end of the display portion 210 a .

[0157] <Comparative Example 1>

[0158] Reference Figure 11 , the arrangement of pixels 212 in the display unit 210b which is different from the display unit 210 is described.

[0159] Figure 11 1 is a schematic top view showing the arrangement of pixels 212 in the display unit 210b of the display device 10 according to one embodiment of the present invention. Specifically, Figure 11 Pixels 212 are shown as part of the display unit 210b of the display device 10. In this comparative example, red light is emitted from the first pixel 212R, green light is emitted from the second pixel 212G, and blue light is emitted from the third pixel 212B. In the description of the display unit 210b in this comparative example, descriptions of the same structures as those of the display unit 210 are omitted.

[0160] In the display portion 210b, the first pixels 212R are arranged with the long side of the rectangle oriented in the Y direction and the short side of the rectangle oriented in the X direction. The second pixels 212G are arranged with the long side of the rectangle oriented in the X direction and the short side of the rectangle oriented in the Y direction. The third pixels 212B are arranged with the long side of the rectangle oriented in the Y direction and the short side of the rectangle oriented in the X direction.

[0161] The display portion 210b has first pixels 212R and third pixels 212B arranged alternately in the X direction. In addition, the display portion 210b has first pixels 212R or third pixels 212B and second pixels 212G arranged alternately in the Y direction.

[0162] Alternatively, the display unit 210b may repeatedly arrange a first unit 214a consisting of one first pixel 212R, one second pixel 212G, and one third pixel 212B in the X and Y directions. Within the first unit 214a, the first pixel 212R and the third pixel 212B are arranged adjacent to each other in the X direction, and the first pixel 212R or the third pixel 212B and the second pixel 212G are arranged adjacent to each other in the Y direction. Furthermore, the second pixel 212G is arranged closer to the first pixel 212R than the third pixel 212B.

[0163] In the display portion 210 b , as a result of performing full-light display (full white display), the roughness of the pixels 212 is prominently displayed at the end portion in the Y direction.

[0164] As embodiments of the present invention, the above-mentioned embodiments can be implemented in appropriate combinations as long as they do not contradict each other. In addition, based on the display devices of each embodiment, those skilled in the art may appropriately add, delete, or change the design of structural elements, or add, omit, or change the conditions of processes, as long as they meet the main purpose of the present invention.

[0165] Even if there are other effects different from the effects achieved by the above-described embodiments, the present invention can also achieve effects that are known from the description of this specification or that can be easily predicted by those skilled in the art.

[0166] Description of Reference Numerals

[0167] 10: Display device, 100: Circuit substrate, 102: Substrate, 104, 104e: Light shielding layer, 106: First insulating layer, 108: First wiring layer, 110: Second insulating layer, 112: Semiconductor layer, 114: Third insulating layer, 116, 116f: Second wiring layer, 118: First planarization layer, 120, 120a, 120b, 120c, 120d, 120e, 120f: Anode pad, 120-1, 120c-1, 120d-1: First electrode layer, 120-2, 120c-2, 120d-2: Second electrode layer, 122, 122a, 122b, 122c, 122d, 122e, 122f: cathode pad, 122-1, 122c-1, 122d-1: third electrode layer, 122-2, 122c-2, 122d-2: fourth electrode layer, 200: light emitting diode chip (LED chip), 200R: first LED chip, 200G: second LED chip, 200B: third LED chip, 201: substrate, 202: n-type semiconductor layer, 203: light emitting layer, 204: p-type semiconductor layer, 205: p-type Electrode, 206: n-type electrode, 207: anode bump, 208: cathode bump, 210: display portion, 212, 212a, 212b: pixel, 212R: first pixel, 212G: second pixel, 212B: third pixel, 214: first unit, 215: second unit, 220L: first circuit portion, 220R: second circuit portion, 230: connection portion, 241: scan line, 242: signal line, 243: light emission control scan line, 244: current supply line, 244': connection portion, 245: initialization scan line, 246: initialization line, 247: reset scan line, 248: reset line, 249 (Cat): cathode line, 300: transistor, 300-1: first transistor, 300-2: second transistor, 300-3: third transistor, 300-4: fourth transistor, 300-5: fifth transistor, 310: first capacitor, 400: adhesive layer, 500, 500a, 500b, 500c, 500d, 500e, 500f: light transmission area, 500R: first light transmission area, 500G: second light transmission area, 500B: third light transmission area.

Claims

1. A display device that emits light from both sides, comprising: A circuit substrate including a first pixel and a second pixel; A first LED chip is mounted so as to overlap with and be electrically connected to the first anode pad and the first cathode pad of the first pixel; as well as The second LED chip is mounted so as to overlap with and be electrically connected to the second anode pad and the second cathode pad of the second pixel. The first pixel includes a first light-transmitting area, which overlaps with the first LED chip, is located between the first anode pad and the first cathode pad, and transmits light from the first LED chip. The second pixel includes a second light-transmitting area, which overlaps with the second LED chip, is located between the second anode pad and the second cathode pad, and transmits light from the second LED chip. When the circuit substrate is viewed from above, a first area of the first light-transmitting region and a second area of the second light-transmitting region have a first ratio, The first ratio is the first area:the second area=1:0.8 to 1.

2.

2. The display device according to claim 1, wherein The first ratio is the first area:the second area=1:0.9 to 1.

1.

3. The display device according to claim 1, wherein The first anode pad comprises: a first electrode layer; and a second electrode layer on the first electrode layer, The first electrode layer is larger than the second electrode layer.

4. The display device according to claim 1, wherein The first cathode pad comprises: a first electrode layer; and a second electrode layer on the first electrode layer, The first electrode layer is larger than the second electrode layer.

5. The display device according to claim 3 or 4, wherein: The first electrode layer is made of metal material.

6. The display device according to claim 3 or 4, wherein: The second electrode layer is made of a transparent conductive material.

7. The display device according to claim 1, wherein The first LED chip is a red LED chip, The second LED chip is a green LED chip.

8. The display device according to claim 1, wherein The circuit substrate further includes a third pixel, The display device includes a third LED chip, the third LED chip being mounted so as to overlap with and be electrically connected to a third anode pad and a third cathode pad of the third pixel. The third pixel includes a third light-transmitting area, which overlaps with the third LED chip, is located between the third anode pad and the third cathode pad, and transmits light from the third LED chip. When the circuit substrate is viewed from above, the first area of the first light-transmitting region and the third area of the third light-transmitting region have a second ratio, The second ratio is the first area:the third area=1:0.8 to 1.

2.

9. The display device according to claim 8, wherein The second ratio is the first area:the third area=1:0.9 to 1.

1.

10. The display device according to claim 8, wherein The third LED chip is a blue LED chip.

11. The display device according to claim 1, wherein When the circuit substrate is viewed from above, the first light-transmitting region includes a plurality of regions separated by a light-shielding layer.

12. The display device according to claim 11, wherein The light shielding layer is arranged below the transistor.

13. The display device according to claim 12, wherein: When the circuit substrate is viewed from above, the second light-transmitting region includes a plurality of regions separated by a second wiring layer, and the second wiring layer is the same layer as the source electrode or the drain electrode of the transistor.

14. The display device according to claim 11, wherein The potential of the light shielding layer is in a floating state.

15. A display device capable of emitting light from both sides, comprising: Circuit board; as well as LED chips, The circuit substrate comprises: substrate; a light shielding layer on the substrate; a first insulating layer on the light-shielding layer; a first wiring layer above the first insulating layer; a second insulating layer above the first wiring layer; an anode pad connected to the LED chip on the second insulating layer; and a cathode pad connected to the LED chip on the second insulating layer, When viewed from above, the light shielding layer is located between the anode pad and the cathode pad.

16. The display device according to claim 15, wherein The pixel circuit including the first wiring layer and connected to the anode pad does not overlap with the light shielding layer.

17. The display device according to claim 16, wherein: The pixel circuit includes at least a first transistor, a second transistor, a third transistor, a fourth transistor and a fifth transistor, The first to fifth transistors respectively overlap with the anode pad or the cathode pad.

18. The display device according to claim 17, wherein: The first transistor is a light emitting control transistor, The second transistor is a selection transistor, The third transistor is an initialization transistor, The fourth transistor is a reset transistor, The fifth transistor is a driving transistor, The first transistor and the fifth transistor are located inside the outer periphery of the cathode pad. The second transistor, the third transistor, and the fourth transistor are located inside the outer periphery of the anode pad.

19. The display device according to claim 15, wherein: The first wiring layer includes a gate electrode, The second insulating layer includes a gate insulating film.

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