Light-emitting device

Abstract

To obtain a high luminance with efficiency.SOLUTION: An LED display device 1 has: a first thin-film layer 20G that is provided on a substrate surface 10S, and includes a thin-film LED 30G having a thin-film LED 30G bandgap; a second thin-film layer 20B that includes a thin-film LED 30B having a thin-film LED 30B bandgap different from the thin-film LED 30G bandgap; and a third thin-film layer 20R that includes a thin-film LED 30R having a thin-film LED 30R bandgap smaller than the thin-film LED 30G bandgap and the thin-film LED 30B bandgap. The second thin-film layer 20B and the third thin-film layer 20R are formed above the first thin-film layer 20G so as to be overlapped in a predetermined order. The thin-film LED 30R is arranged so that, when seen from a lamination direction, a light absorption region ARa where the thin-film LED 30R is overlapped with the thin-film LEDs 30G and 30B is smaller than a light transmission region ARt where the thin-film LED 30G and the thin-film LED 30B are overlapped with each other.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a light emitting device, and is suitable for application to a light emitting device in which, for example, a semiconductor element is mounted on a circuit board. [Background technology]

[0002] In recent years, light-emitting devices have been proposed that display images by selectively driving a plurality of semiconductor elements mounted in a matrix on a circuit board to emit light. Some such light-emitting devices have semiconductor light-emitting elements stacked in the stacking direction in the order of red, green, and blue semiconductor light-emitting elements from the bottom up, in order from the longest to the shortest bandgap wavelength of the semiconductors (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-62351 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a light emitting device, it is desirable to efficiently obtain high brightness.

[0005] The present invention has been made in consideration of the above points, and aims to propose a light-emitting device that efficiently obtains high brightness. [Means for solving the problem]

[0006] In order to solve the above problem, the light emitting device of the present invention includes a substrate having a substrate surface, and a first band gap provided on the substrate surface. and emits either blue or green light. a first layer including a first light-emitting element and a second layer having a second band gap different from the first band gap; and emits either blue or green light.a second layer including a second light-emitting element; and a third bandgap that is smaller than the first bandgap and the second bandgap. and emits red light and a third layer including a third light-emitting element, the second layer and the third layer being formed above the first layer in a predetermined order, and the third light-emitting element being formed such that, when viewed from a direction perpendicular to the substrate surface, an area where the third light-emitting element overlaps with the first light-emitting element and the second light-emitting element is smaller than an area where the first light-emitting element and the second light-emitting element overlap. , having an area where the first light emitting element and the second light emitting element do not overlap. The layout was changed so that the

[0007] The light emitting device of the present invention includes a substrate and a first band gap layer provided on the substrate. and emits either blue or green light. a first layer including a first light-emitting element and a second layer having a second band gap different from the first band gap; and emits either blue or green light. a second layer including a second light-emitting element, and a third band gap having a smaller band gap than the first and second layers, stacked between the first and second layers; and emits red light and a third layer including a third light-emitting element, wherein the first light-emitting element is arranged such that an area where the first light-emitting element overlaps with the second light-emitting element and the third light-emitting element is smaller than an area where the second light-emitting element overlaps with the third light-emitting element when viewed from the stacking direction. The second light emitting element and the third light emitting element are arranged so as to have an area that does not overlap with the first light emitting element when viewed from the stacking direction. I did so.

[0008] Furthermore, the light emitting device of the present invention includes a substrate having a substrate surface, and a light emitting element provided on the substrate surface, Either blue or green a first layer including a first light-emitting element that emits light of Either blue or green a second layer including a second light-emitting element that emits light of red and a third layer including a third light-emitting element that emits light of a wavelength of 100 nm, wherein the second layer and the third layer are formed above the first layer in a predetermined order, and the third light-emitting element has an area where the third light-emitting element overlaps with the first light-emitting element and the second light-emitting element when viewed from a direction perpendicular to the substrate surface, and , having an area where the first light emitting element and the second light emitting element do not overlap. The layout was changed so that the

[0009] Furthermore, the light emitting device of the present invention includes a substrate, and Either blue or green a first layer including a first light-emitting element that emits light of Either blue or green a second layer including a second light-emitting element that emits light of red and a third layer including a third light-emitting element that emits light of the first light-emitting element. The first light-emitting element is disposed such that, when viewed from the stacking direction, an area where the first light-emitting element overlaps with the second light-emitting element and the third light-emitting element is smaller than an area where the second light-emitting element overlaps with the third light-emitting element. The second light emitting element and the third light emitting element are arranged so as to have an area that does not overlap with the first light emitting element when viewed from the stacking direction. I did so.

[0010] The present invention can remove at least a portion of the third light-emitting element from the path of light emitted from at least the first light-emitting element toward the outside of the light-emitting device, thereby increasing the amount of light emitted from the first light-emitting element that is emitted toward the outside of the light-emitting device without being absorbed by the third light-emitting element. [Effects of the Invention]

[0011] According to the present invention, a light emitting device that efficiently obtains high brightness can be realized. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing the configuration of an LED display device. [Figure 2] 2 is an enlarged plan view of part A in FIG. 1, which is an area equivalent to several pixels, showing the configuration of the LED display unit according to the first embodiment. FIG. [Figure 3] 3 is an enlarged plan view showing the configuration of the circuit board according to the first embodiment, with the thin film layer group removed from FIG. 2. [Figure 4] 3 is a cross-sectional view taken along the line AA in FIG. 2, showing the configuration of a pixel section according to the first embodiment. FIG. [Figure 5] 3 is a cross-sectional view taken along the line BB in FIG. 2, showing the configuration of a pixel section according to the first embodiment. [Figure 6] FIG. 2 is a plan view showing the configuration of a first thin film layer according to the first embodiment. [Figure 7] FIG. 3 is a plan view showing the configuration of a second thin film layer according to the first embodiment. [Figure 8] FIG. 10 is a plan view showing the configuration of a third thin film layer according to the first embodiment. [Figure 9] 7 is a cross-sectional view taken along the line CC in FIG. 6, showing a manufacturing process of the first thin film layer according to the first embodiment. [Figure 10] 8 is a cross-sectional view taken along the line DD in FIG. 7, showing a manufacturing process of the second thin film layer according to the first embodiment. [Figure 11] 9 is a cross-sectional view taken along the line EE in FIG. 8, showing a manufacturing process of the third thin film layer according to the first embodiment. [Figure 12] 3A to 3C are cross-sectional views showing a manufacturing process of the LED display unit according to the first embodiment. [Figure 13] 3 is a cross-sectional view taken along the line AA in FIG. 2, showing a light-emitting state of the LED display unit according to the first embodiment. [Figure 14] FIG. 2 is a plan view showing an overlapping state of thin film layers according to the first embodiment. [Figure 15] 1. FIG. 5 is an enlarged plan view of part A of FIG. 1, which is an area equivalent to several pixels, showing the configuration of a display unit of an LED display according to a second embodiment. [Figure 16] 16 is an enlarged plan view showing the configuration of a circuit board according to a second embodiment, with the thin film layer group removed from FIG. 15. [Figure 17] FIG. 16 is a cross-sectional view taken along the line AA in FIG. 15, showing the configuration of a pixel section according to the second embodiment. [Figure 18] FIG. 16 is a cross-sectional view taken along the line BB in FIG. 15, showing the configuration of a pixel section according to the second embodiment. [Figure 19] FIG. 10 is a plan view showing the configuration of a first thin film layer according to a second embodiment. [Figure 20] FIG. 10 is a plan view showing the configuration of a second thin film layer according to the second embodiment. [Figure 21] FIG. 10 is a plan view showing the configuration of a third thin film layer according to the second embodiment. [Figure 22]20 is a cross-sectional view taken along the line CC in FIG. 19, showing a manufacturing process of the first thin film layer according to the second embodiment. [Figure 23] 21 is a cross-sectional view taken along the line DD in FIG. 20, showing a manufacturing process of the second thin film layer according to the second embodiment. [Figure 24] 22 is a cross-sectional view taken along the line EE in FIG. 21, showing a manufacturing process of the third thin film layer according to the second embodiment. [Figure 25] 10A to 10C are cross-sectional views showing a manufacturing process of the LED display unit according to the second embodiment. [Figure 26] 16 is a cross-sectional view taken along the line FF in FIG. 15, showing a light-emitting state (1) of the LED display unit according to the second embodiment. FIG. [Figure 27] 16 is a cross-sectional view taken along the arrows GG in FIG. 15, showing a light-emitting state (2) of the LED display unit according to the second embodiment. FIG. [Figure 28] FIG. 10 is a plan view showing an overlapping state of thin film layers according to the second embodiment. [Figure 29] 10 is an enlarged plan view of part A, which is an area equivalent to several pixels in FIG. 1, showing the configuration of a display unit of an LED display according to a third embodiment. FIG. [Figure 30] 30 is an enlarged plan view showing the configuration of the circuit board according to the third embodiment, with the thin film layer group removed from FIG. 29. [Figure 31] FIG. 30 is a cross-sectional view taken along the line AA in FIG. 29, showing the configuration of a pixel section according to the third embodiment. [Figure 32] FIG. 30 is a cross-sectional view taken along the line BB in FIG. 29, showing the configuration of a pixel portion according to the third embodiment. [Figure 33] FIG. 10 is a plan view showing the configuration of a first thin film layer according to a third embodiment. [Figure 34] FIG. 10 is a plan view showing the configuration of a second thin film layer according to the third embodiment. [Figure 35] FIG. 10 is a plan view showing the configuration of a third thin film layer according to the third embodiment. [Figure 36] 34 is a cross-sectional view taken along the line CC in FIG. 33, showing a manufacturing process of the first thin film layer according to the third embodiment. [Figure 37] 35 is a cross-sectional view taken along the line DD in FIG. 34, showing a manufacturing process of the second thin film layer according to the third embodiment. [Figure 38] 36 is a cross-sectional view taken along the line EE in FIG. 35, showing a manufacturing process of the third thin film layer according to the third embodiment. [Figure 39] 10A to 10C are cross-sectional views showing a manufacturing process of the LED display unit according to the third embodiment. [Figure 40] 29, showing a light-emitting state of the LED display unit according to the third embodiment. FIG. [Figure 41] FIG. 10 is a plan view showing an overlapping state of thin film layers according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

[0014] 1. First Embodiment [1-1. LED display device configuration] As shown in FIGS. 1 and 2, the LED display device 1 includes an LED display unit 2, a heat dissipation member 3, a connection cable 4, a connection terminal unit 5, and a driver 6. The LED display device 1, also known as a micro LED display, is a display device in which a set of red, green, and blue LED elements corresponds to one pixel. Specifically, the LED display unit 2 is a display device in which elements including inorganic light-emitting diodes (LEDs) are arranged as pixels (one picture element) in a matrix on a circuit board 10, which is an active matrix circuit board. The circuit board 10 is a substrate that electrically connects the LEDs to the wiring layer and has a wiring layer and drive elements and drive circuits connected to the wiring layer to selectively drive the LEDs in the pixel. Hereinafter, the direction from left to right on the paper in FIG. 1 is defined as the +X direction, the direction from top right to bottom left on the paper is defined as the +Y direction, and the direction from bottom to top on the paper is defined as the +Z direction.

[0015] [1-2. Overall configuration of the LED display] As shown in FIGS. 4 and 5 , the LED display unit 2 has a configuration in which a thin-film layer group 18 consisting of three thin-film layers, a first thin-film layer 20G, a second thin-film layer 20B, and a third thin-film layer 20R, is stacked within a display area set on the surface (hereinafter also referred to as substrate surface 10S) on the +Z direction side of a flat circuit board 10. Hereinafter, the first thin-film layer 20G, the second thin-film layer 20B, and the third thin-film layer 20R will be collectively referred to as thin-film layers 20. Each thin-film layer 20 is a film in which light-emitting elements are arranged in a grid pattern, and the film size is equal to the display size of the LED display unit 2. Therefore, in the LED display unit 2, the film of each thin-film layer 20 is not independent for each pixel, but is the size of the entire display, and the area of ​​one film of each thin-film layer 20 occupies the entire display area.

[0016] The heat dissipation member 3 (FIG. 1) is made of a metal material with relatively high thermal conductivity, such as aluminum, and is configured as a flat rectangular parallelepiped overall. The heat dissipation member 3 is installed so as to abut against the LED display unit 2 on the -Z direction side of the LED display unit 2, i.e., on the side opposite to the surface that displays images, etc., thereby dissipating heat from the circuit board 10. The connection cable 4 is electrically connected to a predetermined control device (not shown) via a connection terminal unit 5, and transmits image signals supplied from the control device to the driver 6.

[0017] The driver 6 is mounted on, for example, the surface of the circuit board 10, and is electrically connected to the connection cable 4 and the LED display unit 2. The driver 6 generates red, green, and blue drive signals, i.e., gate drive signals for the circuit board 10, based on image signals supplied via, for example, the connection cable 4, and supplies drive currents based on these drive signals to the LED display unit 2. As a result, the LED display device 1 displays an image in the display area of ​​the LED display unit 2 based on image signals supplied from a control device (not shown) or the like.

[0018] The following describes the pixel section 8, which is a region for one pixel among the circuit board 10 and the thin-film layer group 18 in the LED display unit 2. In the following, the reference numerals of components related to the cathode terminal are suffixed with "C," components related to the thin-film LED 30G of the first thin-film layer 20G are suffixed with "G," components related to the thin-film LED 30B of the second thin-film layer 20B are suffixed with "B," and components related to the thin-film LED 30R of the third thin-film layer 20R are suffixed with "R." In the following, the direction perpendicular to the top surface (light-emitting surface) of the thin-film LEDs 30G, 30B, and 30R on the +Z direction side (i.e., the Z direction) is also referred to as the light-emitting direction De. In the following, the direction in which the first thin-film layer 20G, the second thin-film layer 20B, and the third thin-film layer 20R are stacked (i.e., the Z direction) is also referred to as the stacking direction. Furthermore, hereinafter, the direction along the left-right direction on the paper in Fig. 4, i.e., the direction along the cross section seen from the arrow AA in Fig. 2, will also be referred to as the AA cross section direction Da. Furthermore, hereinafter, the direction along the left-right direction on the paper in Fig. 5, i.e., the direction along the cross section seen from the arrow BB in Fig. 2, will also be referred to as the BB cross section direction Db.

[0019] [1-3. Circuit board configuration] 3, 4, and 5, the circuit board 10 is a CMOS (Complementary MOS) backplane circuit board manufactured by a silicon process. The circuit board 10 has a base portion 10M, an insulating layer 11, connection pads 12 (connection pads 12R, 12G, 12B, and 12C), active elements 14 (active elements 14R, 14G, and 14B), and a wiring layer 16.

[0020] The substrate 10M is a silicon wafer. The insulating layer 11 has sufficient insulating properties and is disposed so as to cover the wiring layer 16 from the +Z direction side.

[0021] The connection pads 12 (connection pads 12R, 12G, 12B, and 12C) are arranged in a matrix (i.e., a grid) on the substrate surface 10S. Hereinafter, the connection pads 12R, 12G, 12B, and 12C will be collectively referred to as connection pads 12. This connection pad 12 corresponds to one pixel, and the four connection pads 12R, 12G, 12B, and 12C form a connection pad set 12T. The connection pad set 12T is arranged so that the light-emitting portion 24 (FIG. 2) is located inside the circumscribing rectangle of the connection pads 12R, 12G, 12B, and 12C (i.e., within the pixel area).

[0022] The connection pad 12R is made of a conductive material and has, for example, a square shape when viewed from the +Z direction side. It is located on the +XY direction side of the connection pad set 12T. The connection pad 12R is also disposed on the -Z direction side of the anode pillar 42aR1 of the vertical wiring 22R, and the surface (upper surface) of the connection pad 12R on the +Z direction side (hereinafter also referred to as the connection pad surface 12RS) is exposed on the substrate surface 10S. The connection pad 12R is electrically connected to the active element 14R inside the circuit board 10, and the connection pad surface 12RS is in contact with and electrically connected to the surface (lower surface) on the -Z direction side of the anode pillar 42aR1 of the first thin film layer 20G (hereinafter also referred to as the anode pillar lower surface 42aR1S2).

[0023] The connection pad 12G has a configuration similar to that of the connection pad 12R and is located on the -X+Y side of the connection pad set 12T. The connection pad 12G is also disposed on the -Z side of the vertical wiring 22G (i.e., the anode pad 44G), and the surface (upper surface) of the connection pad 12G on the +Z side (hereinafter also referred to as the connection pad surface 12GS) is exposed on the substrate surface 10S. The connection pad 12G is also electrically connected to the active element 14G inside the circuit board 10, and the connection pad surface 12GS is in contact with and electrically connected to the surface (lower surface) of the anode pad 44G on the first thin-film layer 20G on the -Z side (hereinafter also referred to as the anode pad surface 44GS).

[0024] The connection pad 12B has a configuration similar to that of the connection pad 12R and is located on the +X and +Y direction side of the connection pad set 12T. The connection pad 12B is also disposed on the −Z direction side of the anode pillar 42aB of the vertical wiring 22B, and the surface (upper surface) of the connection pad 12B on the +Z direction side (hereinafter also referred to as the connection pad surface 12BS) is exposed on the substrate surface 10S. The connection pad 12B is also electrically connected to the active element 14B inside the circuit board 10, and the connection pad surface 12BS is in contact with and electrically connected to the surface (lower surface) of the anode pillar 42aB on the −Z direction side of the first thin-film layer 20G (hereinafter also referred to as the anode pillar lower surface 42aBS2).

[0025] The connection pad 12C has a configuration similar to that of the connection pad 12R and is located on the -XY direction side of the connection pad set 12T. The connection pad 12C is also disposed on the -Z direction side of the cathode pillar 40cG in the vertical wiring 22C, and the surface (upper surface) of the connection pad 12C on the +Z direction side (hereinafter also referred to as the connection pad surface 12CS) is exposed on the substrate surface 10S. The connection pad 12C is also electrically connected to the cathode common wiring of the wiring layer 16 inside the circuit board 10, and the connection pad surface 12CS is in contact with and electrically connected to the surface (lower surface) on the -Z direction side of the cathode pillar 40cG in the first thin-film layer 20G (hereinafter also referred to as the cathode pillar lower surface 40cGS2).

[0026] The active elements 14 (active elements 14R, 14G, and 14B) are arranged in a matrix (i.e., a grid) inside the circuit board 10. Hereinafter, the active elements 14R, 14G, and 14B will also be collectively referred to as the active elements 14.

[0027] Active element 14R is composed of two MOS transistors and one capacitor, and is disposed on the −Z direction side of connection pad 12R and electrically connected to wiring inside wiring layer 16. Active elements 14G and 14B are configured similarly to active element 14R, and are disposed on the −Z direction side of connection pads 12G and 12B, respectively, and electrically connected to wiring inside wiring layer 16.

[0028] Although not shown in detail, the wiring inside the wiring layer 16 is arranged in a matrix (i.e., lattice) and is appropriately electrically connected to the active elements 14 (active elements 14R, 14G, and 14B) and connection pads 12 (12R, 12G, 12B, and 12C), as well as electrically connected to the driving driver 6.

[0029] The circuit board 10 has a board surface 10S that is formed as an extremely flat plane. That is, in the circuit board 10, the insulating layer surface 11S, which is the upper surface of the insulating layer 11, the connection pad surface 12RS, the connection pad surface 12GS, the connection pad surface 12BS, and the connection pad surface 12CS are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the insulating layer surface 11S, the connection pad surface 12RS, the connection pad surface 12GS, the connection pad surface 12BS, and the connection pad surface 12CS are all located on the same plane.

[0030] Specifically, in the circuit board 10, the surface roughness of the substrate surface 10S, i.e., the surface roughness (also called roughness or maximum surface step) Rpv of the insulating layer surface 11S, the connection pad surface 12RS, the connection pad surface 12GS, the connection pad surface 12BS and the connection pad surface 12CS are all 10 nm or less.

[0031] [1-4. Composition of thin film layers] 4 and 5, the thin film layer group 18 includes three thin film layers 20, a first thin film layer 20G, a second thin film layer 20B, and a third thin film layer 20R, stacked from the -Z direction to the +Z direction. The thin film layer group 18 is physically bonded to the circuit board 10 by intermolecular forces and is also electrically connected to the circuit board 10.

[0032] A plurality of pixels (pixel section 8) arranged in a matrix pattern within the area of ​​the LED display section 2 are disposed in the thin film layer group 18. When viewed from the Z direction, the pixel section 8 is mainly composed of four vertical wires 22 (vertical wires 22C, 22R, 22G, and 22B) disposed at the four corners and corresponding to anodes and cathodes, and one light-emitting section 24 surrounded by the vertical wires 22 and disposed inside the pixel section 8. Hereinafter, the vertical wires 22C, 22R, 22G, and 22B will also be collectively referred to as vertical wires 22.

[0033] The vertical wiring 22C is made of a conductive material and is composed of a cathode electrode 34R and cathode pillars 40cB and 40cG. The vertical wiring 22R is made of a conductive material and is composed of an anode pad 44R and anode pillars 42aR2 and 42aR1. The vertical wiring 22G is made of a conductive material and is composed of an anode pad 44G. The vertical wiring 22B is made of a conductive material and is composed of an anode pad 44B and an anode pillar 42aB.

[0034] The light-emitting unit 24 is configured by the thin-film LEDs 30G, 30B, and 30R overlapping when viewed from the Z direction (light-emitting direction De) so as to be aligned from the -Z direction to the +Z direction. In this embodiment, the thin-film LEDs 30G and 30B overlap in the Z direction so that their centers coincide with each other, the centers are located at the center of the pixel unit 8 (i.e., the center of the pixel area), and the positions of their outer shapes in the X and Y directions coincide with each other. Furthermore, the thin-film LED 30R has a center shifted in the -X and Y directions relative to the thin-film LEDs 30G and 30B, but partially overlaps with each other. Furthermore, even if the thin-film LEDs 30G, 30B, and 30R do not overlap with each other in the Z direction so that their centers coincide with each other, if they at least partially overlap with each other when viewed from the Z direction, the thin-film LEDs 30G, 30B, and 30R are considered to overlap with each other. Hereinafter, the thin-film LEDs 30G, 30B, and 30R will be collectively referred to as thin-film LEDs 30.

[0035] A common cathode wiring is provided inside the circuit board 10. The common cathode wiring is arranged linearly along the X and Y directions outside the area of ​​the LED display unit 2, and is also arranged linearly along the X direction between a single light-emitting unit row consisting of a plurality of light-emitting units 24 lined up in the X direction and a light-emitting unit row adjacent to the single light-emitting unit row in the Y direction. The common cathode wiring terminates at a common cathode connection terminal of the driver 6.

[0036] [1-4-1. Composition of the first thin film layer] As shown in Figures 4, 5 and 6, the first thin film layer 20G is composed of an underlying transparent insulating material 26G, a transparent insulating material 28G, a thin film LED 30G, an anode electrode 32G, a cathode electrode 34G, lead wiring 36aG and 36cG, interlayer insulating films 38aG and 38cG, anode pillars 42aB and 42aR1, an anode pad 44G and a cathode pillar 40cG.

[0037] The underlying transparent insulating material 26G is made of, for example, SiO2, SiN, transparent polyimide, or the like, and has sufficient insulating properties. This underlying transparent insulating material 26G extends from one end to the other end of the pixel section 8 in the AA cross-sectional direction Da (FIG. 4), but underlying transparent insulating material openings 48aB and 48cG are formed at locations facing the connection pads 12B and 12C of the circuit board 10 in the Z direction, penetrating the underlying transparent insulating material 26G in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 26G (hereinafter also referred to as the underlying transparent insulating material upper surface 26GS1) to the surface (lower surface) on the -Z direction side (hereinafter also referred to as the underlying transparent insulating material lower surface 26GS2).

[0038] Furthermore, although the underlying transparent insulating material 26G extends from one end to the other end of the pixel section 8 in the BB cross-sectional direction Db (Figure 5), underlying transparent insulating material openings 48G and 48aR1 are formed at locations facing the connection pads 12G and 12R, respectively, in the Z direction on the circuit board 10, penetrating the underlying transparent insulating material 26G in the Z direction (light-emitting direction De) from the upper surface 26GS1 of the underlying transparent insulating material to the lower surface 26GS2 of the underlying transparent insulating material.

[0039] The thin-film LED 30G is a thin-film inorganic light-emitting element disposed in the center of the pixel section 8 in the AA cross-sectional direction Da and the BB cross-sectional direction Db, has a predetermined length in the AA cross-sectional direction Da and the BB cross-sectional direction Db, has a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 28G. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30G, is a flat surface extending along the XY direction. The thin-film LED 30G is an LED formed of, for example, a GaP-based material and emitting green light. The anode electrode 32G is disposed on an anode formed in the center of the +Z direction side of the thin-film LED 30G. The cathode electrode 34G is disposed on a cathode formed on the -XY direction side of the +Z direction side of the thin-film LED 30G.

[0040] The lead wiring 36aG (FIG. 5) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32G facing the +Z direction and the anode pad 44G, electrically connecting them. The interlayer insulating film 38aG is made of an insulating material and is disposed between the lead wiring 36aG and the thin-film LED 30G, and is larger than the lead wiring 36aG when viewed along the Z direction. The interlayer insulating film 38aG protects unnecessary portions of the lead wiring 36aG and the thin-film LED 30G from short-circuiting.

[0041] The lead wiring 36cG (FIG. 4) is made of a conductive material similar to the lead wiring 36aG (FIG. 5), and is in contact with the surface (upper surface) of the cathode electrode 34G facing the +Z direction and the cathode pillar 40cG, electrically connecting them. The interlayer insulating film 38cG is made of an insulating material similar to the interlayer insulating film 38aG (FIG. 5), and is disposed between the lead wiring 36cG and the thin-film LED 30G, and is larger than the lead wiring 36cG when viewed along the Z direction. The interlayer insulating film 38cG protects unnecessary portions of the lead wiring 36cG and the thin-film LED 30G from short-circuiting.

[0042] The above-mentioned anode electrode 32G, cathode electrode 34G, and lead-out wiring 36aG and 36cG are made of a transparent conductive material such as ITO (Indium Tin Oxide), and it is desirable that the interlayer insulating films 38aG and 38cG are transparent to the wavelength of light emitted by the thin-film LED 30G.

[0043] The anode pillar 42aB (FIG. 4) is made of a conductive material such as gold, copper, or titanium. It is located opposite the connection pad 12B of the circuit board 10 in the Z direction and constitutes a part of the vertical wiring 22B. Specifically, the anode pillar 42aB is formed on (on the +Z direction side of) a contact metal 46aPL1G, which is a gold-based metal for process stabilization, and is integrated with the contact metal 46aPL1G. The anode pillar 42aB is also composed of a titanium barrier layer, which serves as a copper diffusion prevention film, formed on the contact metal 46aPL1G, a copper seed metal formed on the barrier layer, and a copper plating portion grown and filled on the seed metal. The same applies to the anode pillar 42aR1 and cathode pillar 40cG described below; the anode pillar 42aR1 (FIG. 5) is formed on (on the +Z direction side of) the contact metal 46aPL2G and is integrated with the contact metal 46aPL2G. The cathode pillar 40cG (FIG. 4) is formed integrally with the contact metal 46cG on the +Z side. The anode pillar 42aB has its +Z side surface (hereinafter also referred to as the anode pillar upper surface 42aBS1) exposed from the transparent insulating material 28G. The anode pillar 42aB has its -Z side surface (the anode pillar lower surface 42aBS2) exposed from the underlying transparent insulating material 26G.

[0044] The anode pillar 42aR1 (FIG. 5) is made of a conductive material, similar to the anode pillar 42aB, and is disposed opposite the connection pad 12R of the circuit board 10 in the Z direction, constituting part of the vertical wiring 22R. The anode pillar 42aR1 has its +Z-direction surface (hereinafter also referred to as the anode pillar upper surface 42aR1S1) exposed from the transparent insulating material 28G. The anode pillar 42aR1 also has its -Z-direction surface (the anode pillar lower surface 42aR1S2) exposed from the underlying transparent insulating material 26G.

[0045] The anode pad 44G (FIG. 5) is made of a conductive material similar to the anode pillar 42aB, and is disposed opposite the connection pad 12G of the circuit board 10 in the Z direction to form the vertical wiring 22G. The surface of this anode pad 44G on the −Z direction side (anode pad surface 44GS) is exposed from the underlying transparent insulating material 26G.

[0046] The cathode pillar 40cG (FIG. 4) is made of a conductive material similar to the anode pillar 42aB, and is disposed opposite the connection pad 12C of the circuit board 10 in the Z direction, constituting part of the vertical wiring 22C. The cathode pillar 40cG has its +Z-direction surface (hereinafter also referred to as the cathode pillar upper surface 40cGS1) exposed from the transparent insulating material 28G. The cathode pillar 40cG has its -Z-direction surface (hereinafter also referred to as the cathode pillar lower surface 40cGS2) exposed from the underlying transparent insulating material 26G.

[0047] The transparent insulating material 28G is made of, for example, the same material as the underlying transparent insulating material 26G, and has sufficient insulating properties while being transparent to at least the wavelength of light emitted by the thin-film LEDs 30G. The transparent insulating material 28G is disposed so as to cover the underlying transparent insulating material 26G, the thin-film LEDs 30G, the anode electrodes 32G, the cathode electrodes 34G, the lead wires 36aG and 36cG, the interlayer insulating films 38aG and 38cG, and the anode pad 44G from the +Z direction, excluding the anode pillars 42aB and 42aR1 and the cathode pillar 40cG. The transparent insulating material 28G embeds the thin-film LEDs 30G, the anode electrodes 32G, the cathode electrodes 34G, the lead wires 36aG and 36cG, the interlayer insulating films 38aG and 38cG, and the anode pad 44G between the underlying transparent insulating material 26G.

[0048] This transparent insulating material 28G (Figure 4) has a transparent insulating material opening 50aB formed on the +Z direction side of the underlying transparent insulating material opening 48aB, which penetrates the transparent insulating material 28G in the Z direction (light emitting direction De) from the surface (upper surface) on the +Z direction side of the transparent insulating material 28G (hereinafter also referred to as the transparent insulating material surface 28GS) to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 48aB).

[0049] Furthermore, the transparent insulating material 28G (Figure 5) has a transparent insulating material opening 50aR1 formed on the +Z direction side of the underlying transparent insulating material opening 48aR1, which penetrates the transparent insulating material 28G in the Z direction (light emitting direction De) from the transparent insulating material surface 28GS to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 48aR1).

[0050] Furthermore, the transparent insulating material 28G (Figure 4) has a transparent insulating material opening 50cG formed on the +Z direction side of the underlying transparent insulating material opening 48cG, which penetrates the transparent insulating material 28G in the Z direction (light emitting direction De) from the transparent insulating material surface 28GS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 48cG).

[0051] The base transparent insulating material opening 48aB and the transparent insulating material opening 50aB form a first thin film layer opening 52aB. The first thin film layer opening 52aB is formed from the upper surface of the first thin film layer 20G on the +Z direction side (hereinafter also referred to as the first thin film layer upper surface 20GS1) to the lower surface on the -Z direction side (the first thin film layer lower surface 20GS2), and an anode pillar 42aB is formed therein. The base transparent insulating material opening 48aR1 and the transparent insulating material opening 50aR1 form a first thin film layer opening 52aR1. The first thin film layer opening 52aR1 is formed from the first thin film layer upper surface 20GS1 to the first thin film layer lower surface 20GS2, and an anode pillar 42aR1 is formed therein. Furthermore, the base transparent insulating material opening 48cG and the transparent insulating material opening 50cG form a first thin film layer opening 52cG. The first thin film layer opening 52cG is formed from the first thin film layer upper surface 20GS1 to the first thin film layer lower surface 20GS2, and has a cathode pillar 40cG formed therein.

[0052] Furthermore, the first thin film layer 20G has a first thin film layer upper surface 20GS1 that is formed as an extremely flat plane. That is, in the first thin film layer 20G, the transparent insulating material surface 28GS, the anode pillar upper surfaces 42aBS1 and 42aR1S1, and the cathode pillar upper surface 40cGS1 are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the transparent insulating material surface 28GS, the anode pillar upper surface 42aBS1, the anode pillar upper surface 42aR1S1, and the cathode pillar upper surface 40cGS1 are all located on the same plane.

[0053] Specifically, in the first thin film layer 20G, the surface roughness of the first thin film layer upper surface 20GS1, i.e., the surface roughness Rpv of the transparent insulating material surface 28GS, the anode pillar upper surfaces 42aBS1 and 42aR1S1, and the cathode pillar upper surface 40cGS1, are all 10 nm or less.

[0054] Furthermore, the first thin film layer 20G has a first thin film layer lower surface 20GS2 formed as an extremely flat plane. That is, in the first thin film layer 20G, the lower surface 26GS2 of the underlying transparent insulating material, the anode pillar lower surfaces 42aBS2 and 42aR1S2, the anode pad surface 44GS, the cathode pillar lower surface 40cGS2, and the surfaces (lower surfaces) of the -Z direction sides of the lead-out wirings 36aG and 36cG are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the lower surface 26GS2 of the underlying transparent insulating material, the anode pillar lower surfaces 42aBS2 and 42aR1S2, the anode pad surface 44GS, the cathode pillar lower surface 40cGS2, and the lower surfaces of the -Z direction sides of the lead-out wirings 36aG and 36cG are all located on the same plane.

[0055] Specifically, in the first thin film layer 20G, the surface roughness of the lower surface 20GS2 of the first thin film layer, i.e., the surface roughness Rpv of the lower surface 26GS2 of the underlying transparent insulating material, the lower surfaces 42aBS2 and 42aR1S2 of the anode pillars, the anode pad surface 44GS, the lower surface 40cGS2 of the cathode pillars, and the lower surfaces on the -Z direction side of the lead-out wiring 36aG and 36cG, are all 10 nm or less.

[0056] [1-4-2. Composition of the second thin film layer] As shown in Figures 4, 5 and 7, the second thin film layer 20B is composed of an underlying transparent insulating material 26B, a transparent insulating material 28B, a thin film LED 30B, an anode electrode 32B, a cathode electrode 34B, lead wiring 36aB and 36cB, interlayer insulating films 38aB and 38cB, an anode pillar 42aR2, an anode pad 44B and a cathode pillar 40cB.

[0057] The underlying transparent insulating material 26B is made of the same material as the underlying transparent insulating material 26G, and is sufficiently insulating and transparent to at least the wavelength of light emitted by the thin-film LED 30B. The underlying transparent insulating material 26B extends from one end to the other end of the pixel section 8 in the AA cross-sectional direction Da (FIG. 4). However, underlying transparent insulating material openings 48B and 48cB are formed at locations facing the first thin-film layer openings 52aB and 52cG in the Z direction in the first thin-film layer 20G, respectively, penetrating the underlying transparent insulating material 26B in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 26B (hereinafter also referred to as an underlying transparent insulating material upper surface 26BS1) to the surface (lower surface) on the −Z direction side of the underlying transparent insulating material 26B (hereinafter also referred to as an underlying transparent insulating material lower surface 26BS2).

[0058] Furthermore, although the underlying transparent insulating material 26B extends from one end to the other end of the pixel section 8 in the BB cross-sectional direction Db (Figure 5), at a location opposite the first thin film layer opening 52aR1 in the first thin film layer 20G in the Z direction, an underlying transparent insulating material opening 48aR2 is formed that penetrates the underlying transparent insulating material 26B in the Z direction (light-emitting direction De) from the upper surface 26BS1 of the underlying transparent insulating material to the lower surface 26BS2 of the underlying transparent insulating material.

[0059] The thin-film LED 30B is a thin-film inorganic light-emitting element disposed in the center of the pixel section 8 in the AA cross-sectional directions Da and Db, has a predetermined length in the AA cross-sectional directions Da and Db, has a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 28B. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30B, is a flat surface extending along the XY direction. The thin-film LED 30B is an LED that emits blue light and is made of, for example, a GaN-based material. The anode electrode 32B is disposed on an anode formed in the center of the +Z direction side of the thin-film LED 30B. The cathode electrode 34B is disposed on a cathode formed on the -XY direction side of the +Z direction side of the thin-film LED 30B.

[0060] The lead wiring 36aB (FIG. 4) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32B facing the +Z direction and the anode pad 44B, electrically connecting them. The interlayer insulating film 38aB is made of an insulating material and is disposed between the lead wiring 36aB and the thin-film LED 30B, and is larger than the lead wiring 36aB when viewed along the Z direction. The interlayer insulating film 38aB protects unnecessary portions of the lead wiring 36aB and the thin-film LED 30B from short-circuiting.

[0061] The lead wiring 36cB (FIG. 4) is made of a conductive material like the lead wiring 36aB, and is in contact with the surface (upper surface) of the cathode electrode 34B facing the +Z direction and the cathode pillar 40cB, electrically connecting them. The interlayer insulating film 38cB is made of an insulating material like the interlayer insulating film 38aB, and is disposed between the lead wiring 36cB and the thin-film LEDs 30B, and is larger than the lead wiring 36cB when viewed along the Z direction. The interlayer insulating film 38cB protects unnecessary short circuits between the lead wiring 36cB and the thin-film LEDs 30B.

[0062] The above-mentioned anode electrode 32B, cathode electrode 34B, and lead-out wiring 36aB and 36cB are preferably made of a transparent conductive material such as ITO, and the interlayer insulating films 38aB and 38cB are preferably transparent to the wavelength of light emitted by the thin-film LEDs 30G and 30B.

[0063] The anode pillar 42aR2 (FIG. 5) is made of a conductive material such as gold, copper, or titanium. It is located opposite the anode pillar 42aR1 of the first thin film layer 20G in the Z direction and constitutes a part of the vertical wiring 22R. Specifically, the anode pillar 42aR2 is formed on (on the +Z direction side of) the contact metal 46aPLB, which is a gold-based metal for process stabilization, and is integrated with the contact metal 46aPLB. The anode pillar 42aR2 is also composed of a titanium barrier layer, which is a copper diffusion prevention film, formed on the contact metal 46aPLB, a copper seed metal formed on the barrier layer, and a copper plating portion grown and filled on the seed metal. The same applies to the cathode pillar 40cB (FIG. 4), which will be described later. The cathode pillar 40cB is formed on (on the +Z direction side of) the contact metal 46cB and is integrated with the contact metal 46cB. The anode pillar 42aR2 has its +Z side surface (hereinafter also referred to as the anode pillar upper surface 42aR2S1) exposed from the transparent insulating material 28B. The anode pillar 42aR2 has its −Z side surface (hereinafter also referred to as the anode pillar lower surface 42aR2S2) exposed from the underlying transparent insulating material 26B.

[0064] The anode pad 44B (FIG. 4) is made of a conductive material similar to the anode pillar 42aR2, and is disposed opposite the anode pillar 42aB of the first thin film layer 20G in the Z direction, constituting part of the vertical wiring 22B. The surface of this anode pad 44B on the -Z direction side (hereinafter also referred to as the anode pad surface 44BS) is exposed from the underlying transparent insulating material 26B.

[0065] The cathode pillar 40cB (FIG. 4) is made of a conductive material similar to the anode pillar 42aR2, and is disposed opposite the cathode pillar 40cG of the first thin film layer 20G in the Z direction, constituting part of the vertical wiring 22C. The cathode pillar 40cB has its +Z-direction surface (hereinafter also referred to as the cathode pillar upper surface 40cBS1) exposed from the transparent insulating material 28B. The cathode pillar 40cB has its -Z-direction surface (hereinafter also referred to as the cathode pillar lower surface 40cBS2) exposed from the underlying transparent insulating material 26B.

[0066] The transparent insulating material 28B is made of, for example, the same material as the underlying transparent insulating material 26B, and has sufficient insulating properties while being transparent to at least the wavelength of light emitted by the thin-film LEDs 30G and 30B. The transparent insulating material 28B is disposed so as to cover the underlying transparent insulating material 26B, the thin-film LEDs 30B, the anode electrodes 32B, the cathode electrodes 34B, the lead wires 36aB and 36cB, the interlayer insulating films 38aB and 38cB, and the anode pad 44B from the +Z direction, excluding the anode pillars 42aR2 and the cathode pillars 40cB. The transparent insulating material 28B embeds the thin-film LEDs 30B, the anode electrodes 32B, the cathode electrodes 34B, the lead wires 36aB and 36cB, the interlayer insulating films 38aB and 38cB, and the anode pad 44B between itself and the underlying transparent insulating material 26B.

[0067] This transparent insulating material 28B (Figure 5) has a transparent insulating material opening 50aR2 formed on the +Z direction side of the underlying transparent insulating material opening 48aR2, which penetrates the transparent insulating material 28B in the Z direction (light emitting direction De) from the surface (upper surface) on the +Z direction side of the transparent insulating material 28B (hereinafter also referred to as the transparent insulating material surface 28BS) to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 48aR2).

[0068] Furthermore, the transparent insulating material 28B (Figure 4) has a transparent insulating material opening 50cB formed on the +Z direction side of the underlying transparent insulating material opening 48cB, which penetrates the transparent insulating material 28B in the Z direction (light emitting direction De) from the transparent insulating material surface 28BS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 48cB).

[0069] The base transparent insulating material opening 48aR2 and the transparent insulating material opening 50aR2 form a second thin film layer opening 52aR2. The second thin film layer opening 52aR2 is formed from the upper surface of the second thin film layer 20B on the +Z direction side (hereinafter also referred to as the second thin film layer upper surface 20BS1) to the lower surface on the -Z direction side (hereinafter also referred to as the second thin film layer lower surface 20BS2), and an anode pillar 42aR2 is formed therein. The base transparent insulating material opening 48cB and the transparent insulating material opening 50cB form a second thin film layer opening 52cB. The second thin film layer opening 52cB is formed from the second thin film layer upper surface 20BS1 to the second thin film layer lower surface 20BS2, and a cathode pillar 40cB is formed therein.

[0070] Furthermore, the second thin film layer 20B has an upper surface 20BS1 that is extremely flat and planar. That is, in the second thin film layer 20B, the transparent insulating material surface 28BS, the anode pillar upper surface 42aR2S1, and the cathode pillar upper surface 40cBS1 are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the transparent insulating material surface 28BS, the anode pillar upper surface 42aR2S1, and the cathode pillar upper surface 40cBS1 are all located on the same plane.

[0071] Specifically, in the second thin film layer 20B, the surface roughness of the second thin film layer upper surface 20BS1, that is, the surface roughness Gpv of the transparent insulating material surface 28BS, the anode pillar upper surface 42aR2S1, and the cathode pillar upper surface 40cBS1, is all 10 nm or less.

[0072] Furthermore, the second thin film layer 20B has a second thin film layer lower surface 20BS2 formed as an extremely flat plane. That is, in the second thin film layer 20B, the lower surface 26BS2 of the underlying transparent insulating material, the anode pillar lower surface 42aR2S2, the anode pad surface 44BS, the cathode pillar lower surface 40cBS2, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wirings 36aB and 36cB are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the lower surface 26BS2 of the underlying transparent insulating material, the anode pillar lower surface 42aR2S2, the anode pad surface 44BS, the cathode pillar lower surface 40cBS2, and the lower surfaces of the lead-out wirings 36aB and 36cB are all located on the same plane.

[0073] Specifically, in the second thin film layer 20B, the surface roughness of the lower surface 20BS2 of the second thin film layer, i.e., the surface roughness Gpv of the lower surface 26BS2 of the underlying transparent insulating material, the lower surface 42aR2S2 of the anode pillar, the anode pad surface 44BS, the lower surface 40cBS2 of the cathode pillar, and the lower surfaces of the lead-out wiring 36aB and 36cB, are all 10 nm or less.

[0074] [1-4-3. Composition of the third thin film layer] As shown in Figures 4, 5 and 8, the third thin film layer 20R is composed of an underlying transparent insulating material 26R, a transparent insulating material 28R, a thin film LED 30R, an anode electrode 32R, a cathode electrode 34R, an extraction wiring 36aR, an interlayer insulating film 38aR and an anode pad 44R.

[0075] The underlying transparent insulating material 26R is made of the same material as the underlying transparent insulating material 26G, and is sufficiently insulating while being transparent to at least the wavelengths of light emitted by the thin-film LEDs 30G, 30B, and 30R. The underlying transparent insulating material 26R extends from one end to the other end of the pixel section 8 in the AA cross-sectional direction Da (FIG. 4). However, at a location facing the second thin-film layer opening 52cB in the Z direction in the second thin-film layer 20B, an underlying transparent insulating material opening 48cR is formed, penetrating the underlying transparent insulating material 26R in the Z direction (light-emitting direction De) from the surface (top surface) on the +Z direction side of the underlying transparent insulating material 26R (hereinafter also referred to as the underlying transparent insulating material upper surface 26RS1) to the surface (bottom surface) on the -Z direction side (hereinafter also referred to as the underlying transparent insulating material lower surface 26RS2). A cathode electrode 34R is formed inside the underlying transparent insulating material opening 48cR.

[0076] Furthermore, although the underlying transparent insulating material 26R extends from one end to the other end of the pixel section 8 in the BB cross-sectional direction Db (Figure 5), at a location opposite the second thin film layer opening 52aR2 in the second thin film layer 20B in the Z direction, an underlying transparent insulating material opening 48R is formed that penetrates the underlying transparent insulating material 26R in the Z direction (light-emitting direction De) from the upper surface 26RS1 of the underlying transparent insulating material to the lower surface 26RS2 of the underlying transparent insulating material.

[0077] The thin-film LED 30R is a thin-film inorganic light-emitting element embedded in a transparent insulating material 28R. The thin-film LED 30R is disposed at the center of the pixel unit 8 in the BB cross-sectional direction Db, but is offset from the center of the pixel unit 8 toward the -XY direction. The thin-film LED 30R has a predetermined length in the AA cross-sectional direction Da and the BB cross-sectional direction Db, a thickness in the Z direction of 3 μm or less, and is embedded in the transparent insulating material 28R. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30R, is a flat surface extending along the XY direction. The thin-film LED 30R is a quaternary LED that emits red light and is made of a III-V compound semiconductor material, such as a GaAs-based material. The anode electrode 32R is disposed on an anode formed at the center of the thin-film LED 30R in the +Z direction. The cathode electrode 34R is disposed on a cathode formed on the -XY direction side of the -Z direction side of the thin-film LED 30R.

[0078] The lead wiring 36aR (FIG. 5) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32R facing the +Z direction and the anode pad 44R, respectively, to electrically connect them. The interlayer insulating film 38aR is made of an insulating material and is disposed between the lead wiring 36aR and the thin-film LED 30R, and is formed to be larger than the lead wiring 36aR when viewed along the Z direction. This interlayer insulating film 38aR protects unnecessary parts of the lead wiring 36aR and the thin-film LED 30R from short-circuiting.

[0079] The cathode electrode 34R is disposed opposite the cathode pillar 40cB of the second thin film layer 20B in the Z direction and constitutes a part of the vertical wiring 22C. The cathode electrode 34R has a surface on the -Z direction side (hereinafter also referred to as the cathode electrode surface 34RS) exposed from the underlying transparent insulating material 26R. The cathode electrode 34R has an area equivalent to that of the anode pad 44R, for example.

[0080] The above-mentioned anode electrode 32R, cathode electrode 34R and lead-out wiring 36aR are made of a transparent conductive material such as ITO, and it is desirable that the interlayer insulating film 38aR is transparent to the wavelength of light emitted by the thin-film LEDs 30G, 30B and 30R.

[0081] The anode pad 44R (FIG. 5) is made of a conductive material such as gold, copper, or titanium, and is disposed opposite the anode pillar 42aR2 of the second thin film layer 20B in the Z direction, constituting a part of the vertical wiring 22R. The surface of this anode pad 44R on the -Z direction side (hereinafter also referred to as the anode pad surface 44RS) is exposed from the underlying transparent insulating material 26R.

[0082] The transparent insulating material 28R is made of, for example, the same material as the underlying transparent insulating material 26R, and has sufficient insulating properties while being transparent to at least the wavelength of light emitted by the thin-film LEDs 30G, 30B, and 30R. The transparent insulating material 28R is disposed so as to cover the underlying transparent insulating material 26R, thin-film LED 30R, anode electrode 32R, cathode electrode 34R, lead-out wiring 36aR, interlayer insulating film 38aR, and anode pad 44R from the +Z direction side, and embeds the thin-film LED 30R, anode electrode 32R, cathode electrode 34R, lead-out wiring 36aR, interlayer insulating film 38aR, and anode pad 44R between itself and the underlying transparent insulating material 26R.

[0083] Furthermore, the third thin film layer 20R has a third thin film layer lower surface 20RS2 formed in an extremely flat plane. That is, in the third thin film layer 20R, the underlying transparent insulating material lower surface 26RS2, the anode pad surface 44RS, the cathode electrode surface 34RS, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wiring 36aR are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the underlying transparent insulating material lower surface 26RS2, the anode pad surface 44RS, the cathode electrode surface 34RS, and the lower surfaces of the lead-out wiring 36aR are all located on the same plane.

[0084] Specifically, in the third thin film layer 20R, the surface roughness of the third thin film layer lower surface 20RS2, i.e., the surface roughness Ppv of the underlying transparent insulating material lower surface 26RS2, the anode pad surface 44RS, the cathode electrode surface 34RS, and the lower surface of the lead-out wiring 36aR, are all 10 nm or less. In the following, the lead-out wirings 36aB, 36aG, 36aR, 36cB, and 36cG will also be collectively referred to as the lead-out wiring 36.

[0085] [1-5. Connection between thin film layers and circuit boards] [1-5-1. Physical connection relationship between circuit board and thin film layer] The substrate surface 10S of the circuit board 10 and the first thin film layer lower surface 20GS2 of the first thin film layer 20G are physically bonded by intermolecular forces. The first thin film layer upper surface 20GS1 of the first thin film layer 20G and the second thin film layer lower surface 20BS2 of the second thin film layer 20B are also physically bonded by intermolecular forces. The second thin film layer upper surface 20BS1 of the second thin film layer 20B and the third thin film layer lower surface 20RS2 of the third thin film layer 20R are also physically bonded by intermolecular forces.

[0086] In this way, in the LED display section 2, the substrate surface 10S and the lower surface 20GS2 of the first thin film layer, the upper surface 20GS1 and the lower surface 20BS2 of the second thin film layer, and the upper surface 20BS1 and the lower surface 20RS2 of the second thin film layer are bonded by intermolecular forces rather than by metal bonding.

[0087] [1-5-2. Electrical connection between circuit board and thin film layer] The connection pad 12G (Figure 5) has a connection pad surface 12GS physically bonded to the anode pad surface 44GS of the anode pad 44G of the first thin-film layer 20G by intermolecular forces, and is electrically connected to the anode electrode 32G of the thin-film LED 30G via the anode pad 44G and the lead-out wiring 36aG, as in the conductive path Rga.

[0088] The connection pad surface 12BS of the connection pad 12B (FIG. 4) is physically bonded by intermolecular forces to the anode pillar lower surface 42aBS2 of the anode pillar 42aB of the first thin-film layer 20G. The anode pillar upper surface 42aBS1 of the anode pillar 42aB is physically bonded by intermolecular forces to the anode pad surface 44BS of the anode pad 44B of the second thin-film layer 20B. The anode pad 44B is in physical contact with the lead-out wiring 36aB. Therefore, the connection pad 12B is electrically connected to the anode electrode 32B of the thin-film LED 30B via the anode pillar 42aB, the anode pad 44B, and the lead-out wiring 36aB, like the conductive path Rba.

[0089] The connection pad surface 12RS of the connection pad 12R (FIG. 5) is physically bonded by intermolecular force to the anode pillar lower surface 42aR1S2 of the anode pillar 42aR1 of the first thin-film layer 20G. The anode pillar upper surface 42aR1S1 of the anode pillar 42aR1 is physically bonded by intermolecular force to the anode pillar lower surface 42aR2S2 of the anode pillar 42aR2 of the second thin-film layer 20B. The anode pillar upper surface 42aR2S1 of the anode pillar 42aR2 is physically bonded by intermolecular force to the anode pad surface 44RS of the anode pad 44R of the third thin-film layer 20R. The anode pad 44R is in physical contact with the lead-out wiring 36aR. Therefore, the connection pad 12R is electrically connected to the anode electrode 32R of the thin-film LED 30R via the anode pillar 42aR1, the anode pillar 42aR2, the anode pad 44R, and the lead-out wiring 36aR, like the conductive path Rra.

[0090] The connection pad surface 12CS of the connection pad 12C (FIG. 4) is physically bonded by intermolecular forces to the cathode pillar lower surface 40cGS2 of the cathode pillar 40cG of the first thin-film layer 20G. The cathode pillar upper surface 40cGS1 of the cathode pillar 40cG is physically bonded by intermolecular forces to the cathode pillar lower surface 40cBS2 of the cathode pillar 40cB of the second thin-film layer 20B. The cathode pillar upper surface 40cBS1 of the cathode pillar 40cB is physically bonded by intermolecular forces to the cathode electrode surface 34RS of the cathode electrode 34R of the third thin-film layer 20R. The cathode electrode 34R is in physical contact with the thin-film LED 30R. Therefore, the cathode electrode 34R is electrically connected to the cathode common wiring of the wiring layer 16 via the cathode pillar 40cB, the contact metal 46cB, the cathode pillar 40cG, the contact metal 46cG, and the connection pad 12C, like the conductive path Rc.

[0091] The lead wiring 36cB is in physical contact with the contact metal 46cB. Therefore, the cathode electrode 34B is electrically connected to the cathode common wiring of the wiring layer 16 via the lead wiring 36cB, the contact metal 46cB, the cathode pillar 40cG, the contact metal 46cG, and the connection pad 12C, like the conductive path Rc.

[0092] Furthermore, the lead wiring 36cG is in physical contact with the contact metal 46cG. Therefore, the cathode electrode 34G is electrically connected to the cathode common wiring of the wiring layer 16 via the lead wiring 36cG, the contact metal 46cG, and the connection pad 12C, like the conductive path Rc. The cathode common wiring is also electrically connected to the vertical wiring 22C of other pixel units 8 and is also connected to a common cathode connection terminal (common terminal) of the driver 6.

[0093] [1-6. LED display display manufacturing method] Next, an example of a manufacturing method for the LED display unit 2 of the LED display device 1 will be described with reference to Figures 9, 10, 11, and 12. Incidentally, Figures 9, 10, 11, and 12 are all schematic cross-sectional views showing a state in which the +Z direction is oriented upward. For convenience of explanation, the +Z direction will also be referred to as the upward direction, and the -Z direction will also be referred to as the downward direction.

[0094] [1-6-1. Manufacturing method of first thin film layer] First, a manufacturing method of the first thin film layer 20G will be described with reference to Fig. 9. First, as shown in Fig. 9(A), the manufacturing apparatus 60 performs a step of growing a thin film LED layer 66G on the upper side, i.e., the +Z direction side, of a predetermined LED growth substrate 62G. In this embodiment, a sapphire substrate is used as an example of the LED growth substrate 62G.

[0095] 9(B), the manufacturing apparatus 60 separates the thin-film LED layer 66G from the LED growth substrate 62G by a known laser lift-off method. It is desirable to flatten the separated surface of the thin-film LED layer 66G by polishing or the like.

[0096] 9(C), the manufacturing apparatus 60 sequentially deposits a sacrificial layer 70G and an underlying transparent insulating material 26G on a formation substrate 68G for the first thin film layer 20G, and bonds the thin film LED layer 66G to the underlying transparent insulating material 26G by intermolecular forces. At this time, the upper surfaces (side surfaces in the +Z direction) of the sacrificial layer 70G and the underlying transparent insulating material 26G need to be flat to Rpv=10 [nm] or less, so the manufacturing apparatus 60 may perform a smoothing process such as polishing.

[0097] Next, as shown in FIG. 9(D), the manufacturing equipment 60 performs an etching process on the thin-film LED layer 66G to form thin-film LEDs 30G, and also patterns the underlying transparent insulating material openings 48aB, 48cG, 48aR1 (FIG. 5) and 48G (FIG. 5) in the underlying transparent insulating material 26G.

[0098] Next, as shown in FIG. 9(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32G, a cathode electrode 34G, interlayer insulating films 38cG and 38aG (FIG. 5), lead wiring 36cG and 36aG (FIG. 5), and contact metals 46aPL1G, 46cG, 46aPL2G (FIG. 5), and 46aPDG (FIG. 5) on the thin-film LED 30G and the underlying transparent insulating material 26G.

[0099] 9(F), the manufacturing equipment 60 fills the transparent insulating material 28G and patterns the transparent insulating material 28G to form transparent insulating material openings 50aB, 50cG, and 50aR1 (FIG. 5). Then, by plating, the anode pillar 42aB, cathode pillar 40cG, and anode pillar 42aR1 (FIG. 5) are formed on the contact metals 46aPL1G, 46cG, and 46aPL2G (FIG. 5) exposed from the transparent insulating material openings 50aB, 50cG, and 50aR1 (FIG. 5). The contact metal 46aPDG (FIG. 5) becomes the anode pad 44G.

[0100] Next, as shown in FIG. 9(G), the manufacturing equipment 60 performs a planarization process using chemical mechanical polishing (CMP) to planarize the upper surfaces of the transparent insulating material 28G, the anode pillars 42aB and 42aR1 (FIG. 5), and the cathode pillar 40cG, thereby forming anode pillar upper surfaces 42aBS1 and 42aR1S1 (FIG. 5) on the upper surfaces of the anode pillars 42aB and 42aR1 (FIG. 5), respectively, and forming cathode pillar upper surface 40cGS1 on the upper surface of the cathode pillar 40cG, so that they are exposed from the upper surface of the transparent insulating material 28G.

[0101] [1-6-2. Method for manufacturing the second thin film layer] Next, a method for manufacturing the second thin film layer 20B will be described with reference to Fig. 10. First, as shown in Fig. 10(A), the manufacturing apparatus 60 performs a step of growing a thin film LED layer 66B on the upper side, i.e., the +Z direction side, of a predetermined LED growth substrate 62B. In this embodiment, a sapphire substrate is used as an example of the LED growth substrate 62B.

[0102] 10(B), the manufacturing apparatus 60 separates the thin-film LED layer 66B from the LED growth substrate 62B by a known laser lift-off method. It is desirable to flatten the separated surface of the thin-film LED layer 66B by polishing or the like.

[0103] 10(C), the manufacturing apparatus 60 sequentially deposits a sacrificial layer 70B and an underlying transparent insulating material 26B on the formation substrate 68B of the second thin film layer 20B, and bonds the thin film LED layer 66B to the underlying transparent insulating material 26B by intermolecular forces. At this time, the upper surfaces (side surfaces in the +Z direction) of the sacrificial layer 70B and the underlying transparent insulating material 26B need to be flat to Rpv=10 [nm] or less, so the manufacturing apparatus 60 may perform a smoothing process such as polishing.

[0104] Next, as shown in FIG. 10(D), the manufacturing equipment 60 performs an etching process on the thin-film LED layer 66B to form thin-film LEDs 30B and pattern the underlying transparent insulating material openings 48B, 48cB, and 48aR2 (FIG. 5) in the underlying transparent insulating material 26B.

[0105] Next, as shown in FIG. 10(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32B, a cathode electrode 34B, interlayer insulating films 38cB and 38aB, lead wiring 36cB and 36aB, and contact metals 46aPDB, 46cB, and 46aPLB (FIG. 5) on the thin-film LED 30G and the underlying transparent insulating material 26G.

[0106] 10(F), the manufacturing equipment 60 fills the transparent insulating material 28B, patterns the transparent insulating material openings 50cB and 50aR2 (FIG. 5), and then forms the cathode pillar 40cB and the anode pillar 42aR2 (FIG. 5) on the contact metals 46cB and 46aPLB (FIG. 5) exposed from the transparent insulating material openings 50cB and 50aR2 (FIG. 5) by plating. The contact metal 46aPDB becomes the anode pad 44B.

[0107] Next, as shown in FIG. 10(G), the manufacturing equipment 60 performs a planarization process using chemical mechanical polishing (CMP) to planarize the upper surfaces of the transparent insulating material 28B, the cathode pillar 40cB, and the anode pillar 42aR2 (FIG. 5), thereby forming a cathode pillar upper surface 40cBS1 and an anode pillar upper surface 42aR2S1 on the upper surfaces of the cathode pillar 40cB and the anode pillar 42aR2 (FIG. 5), respectively, so that they are exposed from the upper surface of the transparent insulating material 28B.

[0108] [1-6-3. Manufacturing method of the third thin film layer] Next, a manufacturing method of the third thin-film layer 20R will be described with reference to Fig. 11. First, as shown in Fig. 11(A), the manufacturing apparatus 60 performs a process of forming a lattice-matched sacrificial layer 64R on the upper side of a predetermined LED growth substrate 62R, i.e., on the +Z direction side, and then growing a thin-film LED layer 66R on the upper side. In this embodiment, GaAs is used as the LED growth substrate 62R, and a material such as GaAs containing Al is used as the sacrificial layer 64R, for example.

[0109] 11(B), the manufacturing apparatus 60 separates the thin-film LED layer 66R from the LED growth substrate 62R by etching and removing the sacrificial layer 64R by an etching process. It is desirable to flatten the separated surface of the thin-film LED layer 66R by polishing or the like.

[0110] Next, as shown in Figure 11(C), the manufacturing equipment 60 sequentially deposits a sacrificial layer 70R and an underlying transparent insulating material 26R on the formation substrate 68R of the third thin film layer 20R, and then performs an etching process to pattern underlying transparent insulating material openings 48cR and 48G (Figure 5) in the underlying transparent insulating material 26R.

[0111] Next, as shown in FIG. 11(D), the manufacturing equipment 60 forms the cathode electrode 34R in the underlying transparent insulating material opening 48cR by plating.

[0112] 11(E), the manufacturing equipment 60 performs a planarization process by chemical mechanical polishing (CMP) to planarize the upper surfaces of the underlying transparent insulating material 26R and the cathode electrode 34R, thereby exposing the upper surface of the cathode electrode 34R from the upper surface of the transparent insulating material 28R. Subsequently, the manufacturing equipment 60 bonds the thin-film LED layer 66R to the underlying transparent insulating material 26R by intermolecular forces.

[0113] Next, as shown in FIG. 11(F), the manufacturing equipment 60 performs an etching process on the thin-film LED layer 66R to form thin-film LEDs 30R and pattern underlying transparent insulating material openings 48R (FIG. 5) in the underlying transparent insulating material 26R.

[0114] 11(G), the manufacturing equipment 60 performs a patterning process using techniques such as lithography and sputtering to form an anode electrode 32R, an interlayer insulating film 38aR (FIG. 5), an extraction wiring 36aR, and a contact metal 46aPDR (FIG. 5) on the thin-film LED 30R and the underlying transparent insulating material 26R. The contact metal 46aPDR (FIG. 5) becomes the anode pad 44R.

[0115] Next, the manufacturing equipment 60 fills in the transparent insulating material 28R as shown in Fig. 11(H). The manufacturing equipment 60 may perform a planarization process using chemical mechanical polishing (CMP) to flatten the upper surface of the transparent insulating material 28R.

[0116] [1-6-4.Layered joining process] Next, the lamination and bonding process for laminating the first thin film layer 20G, the second thin film layer 20B, and the third thin film layer 20R manufactured by the above-described manufacturing method onto the circuit board 10 will be described with reference to FIG.

[0117] First, as shown in FIG. 12(A), the manufacturing equipment 60 separates the first thin film layer 20G from the formation substrate 68G by etching and removing the sacrificial layer 70G (FIG. 9). This exposes the anode pillar lower surface 42aBS2, the cathode pillar lower surface 40cGS2, the anode pillar lower surface 42aR1S2 (FIG. 5), and the anode pad surface 44GS (FIG. 5) from the lower surface 26GS2 of the underlying transparent insulating material. The anode pillar lower surface 42aBS2, the cathode pillar lower surface 40cGS2, the anode pillar lower surface 42aR1S2 (FIG. 5), and the anode pad surface 44GS (FIG. 5) are formed flat and flush with the upper surface of the sacrificial layer 70G (FIG. 9). Next, the manufacturing equipment 60 bonds the separated first thin film layer 20G to the upper surface of the circuit board 10 using a known bonding method through intermolecular forces.

[0118] Next, as shown in FIG. 12(B), the manufacturing equipment 60 separates the second thin film layer 20B from the formation substrate 68B by etching and removing the sacrificial layer 70B (FIG. 10). This exposes the cathode pillar lower surface 40cBS2, the anode pad surface 44BS, and the anode pillar lower surface 42aR2S2 (FIG. 5) from the lower surface 26BS2 of the underlying transparent insulating material. The cathode pillar lower surface 40cBS2, the anode pad surface 44BS, and the anode pillar lower surface 42aR2S2 (FIG. 5) are formed flat and flush with the upper surface of the sacrificial layer 70B (FIG. 10). Next, the manufacturing equipment 60 bonds the separated second thin film layer 20B to the upper surface of the first thin film layer 20G, which was bonded to the circuit substrate 10 in FIG. 12(A), using intermolecular forces by a known bonding method.

[0119] Next, as shown in FIG. 12(C), the manufacturing equipment 60 separates the third thin film layer 20R from the formation substrate 68R by etching and removing the sacrificial layer 70R (FIG. 11). This exposes the cathode electrode surface 34RS and the anode pad surface 44RGS (FIG. 5) from the lower surface 26RS2 of the underlying transparent insulating material. The cathode electrode surface 34RS and the anode pad surface 44RS (FIG. 5) are formed flat and flush with the upper surface of the sacrificial layer 70R (FIG. 11). Next, the manufacturing equipment 60 uses a known bonding method to bond the separated third thin film layer 20R to the upper surface of the second thin film layer 20B, which was bonded to the first thin film layer 20G in FIG. 12(B), using intermolecular forces.

[0120] [1-7. Operation] In this configuration, when the LED display device 1 drives the LED display section 2, power, a clock signal, image data, and the like are input to the driver 6 from an external circuit (not shown) via the connection terminal section 5. Subsequently, the LED display device 1 selectively supplies on / off signals and drive currents for the active elements 14R, 14G, and 14B from the driver 6 to the wiring layer 16 of the circuit board 10. The supplied drive currents pass through the connection pads 12, the vertical wiring 22R, 22G, and 22B, and the lead-out wiring 36 in each thin-film layer (the first thin-film layer 20G, the second thin-film layer 20B, and the third thin-film layer 20R), and are supplied to the thin-film LEDs 30R, 30G, and 30B in response to the on / off of the active elements 14R, 14G, and 14B. This causes the LED display section 2 to emit light.

[0121] [1-8. LED display illumination] 13, when the LED display unit 2 emits light, the thin-film LED 30B is made of a GaN substrate and absorbs wavelengths shorter than 365 nm (blue), which corresponds to Eg = 3.4 eV. Therefore, the green light LG emitted from the thin-film LED 30G is not absorbed by the thin-film LED 30B but is transmitted through the thin-film LED 30B. Furthermore, the portions of the second thin-film layer 20B other than the thin-film LED 30B and the portions of the third thin-film layer 20R other than the thin-film LED 30R are transparent to the wavelength of the green light LG. Therefore, the green light LG is transmitted through the portions of the second thin-film layer 20B other than the thin-film LED 30B and the portions of the third thin-film layer 20R other than the thin-film LED 30R. On the other hand, the thin-film LED 30R is made of a GaAs substrate and absorbs wavelengths shorter than 660 nm (red), which corresponds to Eg = 1.9 eV. Therefore, the green light LG emitted toward the third thin-film layer 20R is absorbed by the thin-film LED 30R. Furthermore, the green light LG emitted toward the third thin film layer 120R is reflected by the cathode electrode 34R.

[0122] Furthermore, since the portions of the third thin-film layer 20R other than the thin-film LED 30R are transparent to the wavelength of the blue light LB emitted from the thin-film LED 30B, the blue light LB passes through the portions of the third thin-film layer 20R other than the thin-film LED 30R. On the other hand, since the thin-film LED 30R is made of a GaAs substrate and absorbs wavelengths shorter than 660 [nm] (red), which corresponds to Eg = 1.9 [eV], the blue light LB emitted toward the third thin-film layer 20R is absorbed by the thin-film LED 30R. Furthermore, the green light LG emitted toward the third thin-film layer 120R is reflected by the cathode electrode 34R.

[0123] Furthermore, the portions of the third thin-film layer 20R other than the thin-film LED 30R are transparent to the wavelength of the red light LR emitted from the thin-film LED 30R, so the red light LR passes through the portions of the third thin-film layer 20R other than the thin-film LED 30R.

[0124] In the pixel unit 8 according to the present embodiment, the thin-film LED 30R is arranged with its center displaced in the −XY direction (i.e., offset) with respect to the centers of the thin-film LEDs 30G and 30B. As a result, the third thin-film layer 20R absorbs some of the green light LG and LB that is directed toward the thin-film LED 30R and reflects some of the green light that is directed toward the cathode electrode 34R by the cathode electrode 34R, but transmits the green light LG and LB that is directed toward portions other than the thin-film LED 30R and the cathode electrode 34R and directs it in the +Z direction.

[0125] [1-9. Overlapping of thin film layers] Here, when the pixel unit 8 is viewed from the +Z direction along the light-emitting direction De, as shown in Fig. 14(A), the hatched region where the thin-film LED 30R located furthest in the +Z direction overlaps with both the thin-film LED 30G and the thin-film LED 30B located further in the -Z direction than the thin-film LED 30R, is called the light-absorbing region ARa. In the first embodiment, the thin-film LED 30G and the thin-film LED 30B are not offset from each other, so the light-absorbing region ARa is the region where the thin-film LED 30R overlaps with the thin-film LED 30G. Furthermore, when the pixel unit 8 is viewed from the +Z direction along the light-emitting direction De, as shown in Fig. 14(B), the hatched region where the thin-film LED 30G and the thin-film LED 30B located further in the -Z direction than the thin-film LED 30R overlap is called the light-transmitting region ARt. In the pixel section 8 according to the present embodiment, the thin-film LEDs 30G, 30B, and 30R are arranged so that the light absorbing region ARa (FIG. 14(A)) is smaller than the light transmitting region ARt (FIG. 14(B)).

[0126] [1-10.Effects] Here, the thin-film LED 30R, which is a GaAs substrate, absorbs wavelengths shorter than 660 nm (red), which corresponds to Eg = 1.9 eV, the thin-film LED 30G, which is a GaP substrate, absorbs wavelengths shorter than 564 nm (green), which corresponds to Eg = 2.2 eV, and the thin-film LED 30B, which is a GaN substrate, absorbs wavelengths shorter than 365 nm (blue), which corresponds to Eg = 3.4 eV. In other words, the wider the band gap of the semiconductor of the thin-film LED 30, the wider the range of wavelengths that it transmits light.

[0127] Because of these characteristics, in an LED display device, which is a stacked semiconductor light-emitting device, the thin-film LEDs 30R, 30G, and 30B are stacked in this order from the -Z side (lowest layer) to the +Z side (top layer), so that the thin-film LEDs 30 with the smallest band gap are arranged to the thin-film LEDs 30 with the largest band gap, thereby preventing the light from the lower thin-film LEDs 30 from being absorbed by the upper thin-film LEDs 30.

[0128] However, the light-emitting efficiencies of the thin-film LEDs 30R, 30G, and 30B are not equal to one another. In particular, the light-emitting efficiency of the thin-film LED 30R is generally lower than that of the thin-film LEDs 30G and 30B. That is, even if the same current is passed through the thin-film LEDs 30R, 30G, and 30B, the thin-film LED 30R emits light that is dimmer than the thin-film LEDs 30G and 30B. Furthermore, even if a transparent resin is used in the top layer other than the thin-film LED 30B, the transmittance of the top layer for the red light LR emitted from the thin-film LED 30R cannot be 100%. Furthermore, even if a transparent resin is used in the intermediate layer between the top and bottom layers other than the thin-film LED 30G, the transmittance of the intermediate layer for the red light LR emitted from the thin-film LED 30R cannot be 100%.

[0129] Therefore, even if the thin-film LED 30R is placed in the bottom layer, the band gap between the thin-film LED 30G in the middle layer and the thin-film LED 30B in the top layer, which are the layers above the bottom layer, is large enough to transmit red light LR, because the luminous efficiency of the thin-film LED 30R is low and the transmittance of the red light LR from the middle layer and the top layer is lower than 100%, the red light LR emitted from the LED display unit to the outside is attenuated. As a result, the red light LR emitted from the LED display unit to the outside becomes dim. In this case, in an LED display unit that expresses white by mixing red, green, and blue, the maximum brightness of the white light depends on the maximum brightness of the thin-film LED 30R, whose light emitted from the LED display unit to the outside is relatively low compared to the thin-film LEDs 30G and 30B. Therefore, it becomes difficult to increase the brightness of white light in the LED display unit, making it difficult to improve the overall display brightness.

[0130] In response to this, it is conceivable to prevent the red light LR from being attenuated by the thin-film LEDs 30G and 30B by aligning the centers of the thin-film LEDs 30R, 30G, and 30B and placing the thin-film LED 30R on the top layer. However, as mentioned above, the thin-film LED 30R is a GaAs substrate, and therefore absorbs and does not transmit blue light LB and green light LG, which have wavelengths shorter than 660 nm (red), corresponding to Eg = 1.9 eV. This results in dim blue light LB and green light LG emitted to the outside from the LED display.

[0131] In contrast, in the LED display device 1 according to the first embodiment, the thin-film LED 30G of the first thin-film layer 20G, the thin-film LED 30B of the second thin-film layer 20B, and the thin-film LED 30R of the third thin-film layer 20R are stacked in this order, so that the thin-film LED 30R is arranged on the top layer. Also, in the LED display device 1, the center of the thin-film LED 30R is arranged offset from the thin-film LEDs 30G and 30B.

[0132] Therefore, compared to when the thin-film LEDs 30G, 30B, and 30R are arranged with their centers aligned, the LED display device 1 can move at least a part of the thin-film LED 30R away from the paths of the green light LG and blue light LB directed in the +Z direction, thereby increasing the amount of green light LG and blue light LB that is not absorbed by the thin-film LED 30R and is emitted to the outside of the LED display device 1. This allows the LED display device 1 to efficiently extract to the outside the green light LG and blue light LB that is absorbed by the thin-film LED 30R, which is arranged below the thin-film LED 30R on the uppermost third thin-film layer 20R.

[0133] Therefore, in the LED display device 1, when the light emission intensity of the thin-film LEDs 30G and 30B is sufficiently high relative to the thin-film LED 30R, it is possible to arrange the thin-film LED 30R, which has a lower light emission intensity, in the top layer compared to when the thin-film LED 30R is arranged in the bottom layer, thereby preventing the maximum brightness of white from depending on the maximum brightness of the thin-film LED 30R and improving the display brightness of the entire LED display section 2.

[0134] Furthermore, in the LED display device 1, the red light LR of the thin-film LED 30R is not attenuated by other thin-film layers 20, so there is no need to pass a large current through the thin-film LED 30R to increase the light emission intensity of the thin-film LED 30R, which has poor light emission efficiency. This makes it possible to improve the display brightness of the entire LED display unit 2 with less power, and to improve the light emission efficiency of the entire LED display unit 2.

[0135] Thus, the LED display device 1 can place the thin-film LEDs 30R, which have low light-emitting efficiency, on the top layer, thereby improving the display brightness of the entire LED display section 2 and efficiently extracting the green light LG and blue light LB absorbed by the thin-film LEDs 30R to the outside.

[0136] According to the above configuration, the LED display device 1 includes a circuit board 10 having a board surface 10S as a board surface, a first thin-film layer 20G provided on the board surface 10S and including a thin-film LED 30G as a first light-emitting element having the bandgap of the thin-film LED 30G as a first bandgap and emitting light of the wavelength of the thin-film LED 30G as a first wavelength, a second thin-film layer 20B including a thin-film LED 30B as a second light-emitting element having the bandgap of the thin-film LED 30B as a second bandgap different from the bandgap of the thin-film LED 30G and emitting light of the thin-film LED 30B as a second wavelength different from the wavelength of the thin-film LED 30G, and a second thin-film layer 20B including a thin-film LED 30B as a second light-emitting element having the bandgap of the thin-film LED 30B as a second bandgap different from the wavelength of the thin-film LED 30G. and a third thin-film layer 20R including a thin-film LED 30R having a band gap of the thin-film LED 30R smaller than that of the first thin-film LED 30G and emitting light of the thin-film LED 30R at a third wavelength longer than that of the thin-film LED 30G and the thin-film LED 30B, the second thin-film LED 30B and the third thin-film layer 20R being formed above the first thin-film layer 20G (on the +Z direction side) and stacked in a predetermined order, and the thin-film LED 30R is arranged such that, when viewed from the stacking direction perpendicular to the substrate surface 10S, a light absorbing region ARa, which is a region where the thin-film LED 30R overlaps with the thin-film LED 30G and the thin-film LED 30B, is smaller than a light transmitting region ARt, which is a region where the thin-film LED 30G and the thin-film LED 30B overlap.

[0137] This allows the LED display device 1 to move at least a portion of the thin-film LED 30R away from the path of at least the green light LG heading in the +Z direction, thereby increasing the amount of green light LG emitted outside the LED display device 1 without being absorbed by the thin-film LED 30R.

[0138] 2. Second Embodiment [2-1. LED display device configuration] 1 and 15 in which the same reference numerals are used for components corresponding to those in Fig. 2, an LED display device 101 according to the second embodiment is configured similarly to the LED display device 1 except that an LED display unit 102 differs from the LED display unit 2. The LED display unit 102 is a display device in which elements including inorganic light emitting diodes (LEDs) are arranged as pixels (one picture element) in a matrix on a circuit board 110, which is an active matrix circuit board.

[0139] [2-2. Overall configuration of the LED display] 17 and 18, in which the same reference numerals are used for components corresponding to those in FIGS. 4 and 5, the LED display unit 102 has a configuration in which a thin film layer group 118 consisting of three thin film layers, a first thin film layer 120B, a second thin film layer 120G, and a third thin film layer 120R, is stacked within a display area set on the surface (hereinafter also referred to as substrate surface 10S) on the +Z direction side of a flat circuit board 110. Hereinafter, the first thin film layer 120B, the second thin film layer 120G, and the third thin film layer 120R will also be collectively referred to as thin film layers 120. Each thin film layer 120 has a film shape in which light-emitting elements are arranged in a lattice pattern, and the film size is the same as that of the thin film layer 20 according to the first embodiment.

[0140] The following describes the pixel section 108, which is a region for one pixel, of the circuit board 110 and the thin film layer group 118 in the LED display unit 102. In the following, the reference numerals of the members related to the cathode terminal are suffixed with "C," the reference numerals of the members related to the thin film LED 30B of the first thin film layer 120B are suffixed with "B," the reference numerals of the members related to the thin film LED 30G of the second thin film layer 120G are suffixed with "G," and the reference numerals of the members related to the thin film LED 30R of the third thin film layer 120R are suffixed with "R."

[0141] [2-3. Circuit board configuration] 16, 17, and 18, in which the same reference numerals are used to designate components corresponding to those in FIG. 3, the circuit board 110 is a CMOS backplane circuit board manufactured by a silicon process. Compared to the circuit board 10, the circuit board 110 according to the second embodiment has connection pads 112 (connection pads 112R, 112G, 112B, and 112C) and active elements 114 (active elements 114R, 114G, and 114B) that are different from the connection pads 12 (connection pads 12R, 12G, 12B, and 12C) and active elements 14 (active elements 14R, 14G, and 14B), but is otherwise configured similarly.

[0142] The connection pads 112 (connection pads 112R, 112G, 112B, and 112C) are arranged in a matrix (i.e., a grid) on the substrate surface 10S. Hereinafter, the connection pads 112R, 112G, 112B, and 112C will be collectively referred to as connection pads 112. This connection pad 112 corresponds to one pixel, and the four connection pads 112R, 112G, 112B, and 112C form a connection pad set 112T. The connection pad set 112T is arranged so that the light-emitting portion 124 (FIG. 15) is located inside the circumscribing rectangle of the connection pads 112R, 112G, 112B, and 112C (i.e., within the pixel area).

[0143] The connection pad 112R is made of a conductive material and has, for example, a square shape when viewed from the +Z direction side. It is located on the +XY direction side of the connection pad set 112T. The connection pad 112R is also disposed on the -Z direction side of the anode pillar 142aR1 of the vertical wiring 122R, and the surface (upper surface) of the connection pad 112R on the +Z direction side (hereinafter, also referred to as the connection pad surface 112RS) is exposed on the substrate surface 10S. The connection pad 112R is electrically connected to the active element 114R inside the circuit board 110, and the connection pad surface 112RS is in contact with and electrically connected to the surface (lower surface) on the -Z direction side of the anode pillar 142aR1 of the first thin film layer 120B (hereinafter, also referred to as the anode pillar lower surface 142aR1S2).

[0144] The connection pad 112B has a configuration similar to that of the connection pad 112R and is located on the -X+Y direction side of the connection pad set 112T. The connection pad 112B is also disposed on the -Z direction side of the vertical wiring 122B (i.e., the anode pad 144B), and the surface (upper surface) of the connection pad 112B on the +Z direction side (hereinafter also referred to as the connection pad surface 112BS) is exposed on the substrate surface 10S. The connection pad 112B is also electrically connected to the active element 114B inside the circuit board 110, and the connection pad surface 112BS is in contact with and electrically connected to the surface (lower surface) of the anode pad 144B on the first thin-film layer 120B on the -Z direction side (hereinafter also referred to as the anode pad surface 144BS).

[0145] The connection pad 112G has a configuration similar to that of the connection pad 112R and is located on the +X and +Y direction side of the connection pad set 112T. The connection pad 112G is also disposed on the -Z direction side of the anode pillar 142aG of the vertical wiring 122G, and the surface (upper surface) of the connection pad 112G on the +Z direction side (hereinafter also referred to as the connection pad surface 112GS) is exposed on the substrate surface 10S. The connection pad 112G is also electrically connected to the active element 114G inside the circuit board 110, and the connection pad surface 112GS is in contact with and electrically connected to the surface (lower surface) of the anode pillar 142aG on the -Z direction side of the first thin film layer 120B (hereinafter also referred to as the anode pillar lower surface 142aGS2).

[0146] The connection pad 112C has a configuration similar to that of the connection pad 112R and is located on the -XY direction side of the connection pad set 112T. The connection pad 112C is also disposed on the -Z direction side of the cathode pillar 140cB in the vertical wiring 122C, and the surface (upper surface) of the connection pad 112C on the +Z direction side (hereinafter also referred to as the connection pad surface 112CS) is exposed on the substrate surface 10S. The connection pad 112C is also electrically connected to the cathode common wiring of the wiring layer 16 inside the circuit board 110, and the connection pad surface 112CS is in contact with and electrically connected to the surface (lower surface) on the -Z direction side of the cathode pillar 140cB in the first thin-film layer 120B (hereinafter also referred to as the cathode pillar lower surface 140cBS2).

[0147] The active elements 114 (active elements 114R, 114G, and 114B) are arranged in a matrix (i.e., a grid) inside the circuit board 110. Hereinafter, the active elements 114R, 114G, and 114B will also be collectively referred to as active elements 114.

[0148] Active element 114R is composed of two MOS transistors and one capacitor, and is disposed on the −Z direction side of connection pad 112R and electrically connected to wiring inside wiring layer 16. Active elements 114G and 114B are configured similarly to active element 114R, and are disposed on the −Z direction side of connection pads 112G and 112B, respectively, and electrically connected to wiring inside wiring layer 16.

[0149] Although not shown in detail, the wiring inside the wiring layer 16 is arranged in a matrix (i.e., lattice) and is appropriately electrically connected to the active elements 114 (active elements 114R, 114G, and 114B) and connection pads 112 (112R, 112G, 112B, and 112C), as well as electrically connected to the driving driver 6.

[0150] The circuit board 110 has a board surface 10S that is formed as an extremely flat plane. That is, in the circuit board 110, the insulating layer surface 11S, which is the upper surface of the insulating layer 11, the connection pad surface 112RS, the connection pad surface 112GS, the connection pad surface 112BS, and the connection pad surface 112CS are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the insulating layer surface 11S, the connection pad surface 112RS, the connection pad surface 112GS, the connection pad surface 112BS, and the connection pad surface 112CS are all located on the same plane.

[0151] Specifically, in the circuit board 110, the surface roughness of the substrate surface 10S, i.e., the surface roughness (also called roughness or maximum surface step) Rpv of the insulating layer surface 11S, the connection pad surface 112RS, the connection pad surface 112GS, the connection pad surface 112BS and the connection pad surface 112CS are all 10 nm or less.

[0152] [2-4. Composition of thin film layers] 17 and 18, the thin film layer group 118 is formed by stacking three thin film layers 120, namely, a first thin film layer 120B, a second thin film layer 120G, and a third thin film layer 120R, from the -Z direction to the +Z direction. The thin film layer group 118 is physically bonded to the circuit board 110 by intermolecular forces and is also electrically connected to the circuit board 110.

[0153] A plurality of pixels (pixel section 108) arranged in a matrix pattern within the region of the LED display section 102 are disposed in the thin film layer group 118. When viewed from the Z direction, the pixel section 108 is mainly composed of four vertical wires 122 (vertical wires 122C, 122R, 122G, and 122B) disposed at the four corners and corresponding to anodes and cathodes, and one light-emitting section 124 surrounded by the vertical wires 122 and disposed inside the pixel section 108. Hereinafter, the vertical wires 122C, 122R, 122G, and 122B will also be collectively referred to as vertical wires 122.

[0154] The vertical wiring 122C is made of a conductive material and is composed of a cathode electrode 134R, and cathode pillars 140cG and 140cB. The vertical wiring 122R is made of a conductive material and is composed of an anode pad 144R, and anode pillars 142aR2 and 142aR1. The vertical wiring 122B is made of a conductive material and is composed of an anode pad 144B. The vertical wiring 122G is made of a conductive material and is composed of an anode pad 144G and an anode pillar 142aG.

[0155] The light-emitting section 124 is configured by the thin-film LEDs 30B, 30G, and 30R overlapping each other when viewed from the Z direction (light-emitting direction De) so as to be aligned from the -Z direction side toward the +Z direction side. In this embodiment, the thin-film LEDs 30B, 30G, and 30R overlap in the Z direction so that their centers do not coincide with each other. Specifically, the center of the thin-film LED 30B is located at the center of the pixel section 108 (i.e., the center of the pixel area). The center of the thin-film LED 30G is shifted in the -X and +Y directions relative to the thin-film LED 30B, but they partially overlap. The center of the thin-film LED 30R is shifted in the -X and +Y directions relative to the thin-film LED 30B, but they partially overlap.

[0156] A common cathode wiring is provided inside the circuit board 110. The common cathode wiring is arranged linearly along the X and Y directions outside the area of ​​the LED display unit 102, and is also arranged linearly along the X direction between a single light-emitting unit row consisting of a plurality of light-emitting units 124 lined up in the X direction and a light-emitting unit row adjacent to the single light-emitting unit row in the Y direction. The common cathode wiring terminates at a common cathode connection terminal of the driver 6.

[0157] [2-4-1. Composition of the first thin film layer] As shown in Figures 17 and 18, and Figure 19 in which the same symbols are used for components corresponding to those in Figure 6, the first thin film layer 120B is composed of an underlying transparent insulating material 126B, a transparent insulating material 128B, a thin film LED 30B, an anode electrode 32B, a cathode electrode 34B, lead-out wiring 136aB and 136cB, interlayer insulating films 138aB and 138cB, anode pillars 142aG and 142aR1, an anode pad 144B, and a cathode pillar 140cB.

[0158] The underlying transparent insulating material 126B is made of, for example, SiO2, SiN, transparent polyimide, etc., and has sufficient insulating properties. This underlying transparent insulating material 126B extends from one end to the other end of the pixel unit 108 in the AA cross-sectional direction Da (FIG. 17), but underlying transparent insulating material openings 148aG and 148cB are formed at locations facing the connection pads 112G and 112C on the circuit board 110 in the Z direction, penetrating the underlying transparent insulating material 126B in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 126B (hereinafter also referred to as the underlying transparent insulating material upper surface 126BS1) to the surface (lower surface) on the -Z direction side (hereinafter also referred to as the underlying transparent insulating material lower surface 126BS2).

[0159] Furthermore, although the underlying transparent insulating material 126B extends from one end to the other end of the pixel section 108 in the BB cross-sectional direction Db (Figure 18), underlying transparent insulating material openings 148B and 148aR1 are formed at locations facing the connection pads 112B and 112R, respectively, in the Z direction on the circuit board 110, penetrating the underlying transparent insulating material 126B in the Z direction (light-emitting direction De) from the upper surface 126BS1 of the underlying transparent insulating material to the lower surface 126BS2 of the underlying transparent insulating material.

[0160] The thin-film LED 30B is a thin-film inorganic light-emitting element disposed in the center of the pixel unit 108 in the AA cross-sectional directions Da and Db, has a predetermined length in the AA cross-sectional directions Da and Db, has a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 128B. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30B, is a flat surface extending along the XY direction. The thin-film LED 30B is an LED that emits blue light and is made of, for example, a GaN-based material. The anode electrode 32B is disposed on an anode formed in the center of the +Z direction side of the thin-film LED 30B. The cathode electrode 34B is disposed on a cathode formed on the -XY direction side of the +Z direction side of the thin-film LED 30B.

[0161] The lead-out wiring 136aB (FIG. 18) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32B on the +Z direction side and the anode pad 144B, respectively, to electrically connect them. The interlayer insulating film 138aB is made of an insulating material and is disposed between the lead-out wiring 136aB and the thin-film LED 30B, and is formed to be larger than the lead-out wiring 136aB when viewed along the Z direction. This interlayer insulating film 138aB protects unnecessary portions of the lead-out wiring 136aB and the thin-film LED 30B from short-circuiting.

[0162] The lead-out wiring 136cB (FIG. 17) is made of a conductive material similar to the lead-out wiring 136aB (FIG. 18), and is in contact with the surface (upper surface) of the cathode electrode 34B on the +Z direction side and the cathode pillar 140cB, electrically connecting them. The interlayer insulating film 138cB is made of an insulating material similar to the interlayer insulating film 138aB (FIG. 18), and is disposed between the lead-out wiring 136cB and the thin-film LEDs 30B, and is larger than the lead-out wiring 136cB when viewed along the Z direction. The interlayer insulating film 138cB protects unnecessary short circuits between the lead-out wiring 136cB and the thin-film LEDs 30B.

[0163] The above-mentioned anode electrode 32B, cathode electrode 34B, and lead-out wiring 136aB and 136cB are made of a transparent conductive material such as ITO, and the interlayer insulating films 138aB and 138cB are preferably transparent to the wavelength of light emitted by the thin-film LED 30B.

[0164] The anode pillar 142aG (FIG. 17) is made of a conductive material such as gold, copper, or titanium, and is disposed opposite the connection pad 112G of the circuit board 110 in the Z direction, constituting a part of the vertical wiring 122G. Specifically, the anode pillar 142aG is formed on (on the +Z direction side of) the contact metal 146aPL1B, which is a gold-based metal for process stabilization, and is integrated with the contact metal 146aPL1B. The anode pillar 142aG is also made of a titanium barrier layer, which serves as a copper diffusion prevention film, formed on the contact metal 146aPL1B, a copper seed metal formed on the barrier layer, and a copper plating portion that grows and fills the seed metal. The same applies to the anode pillar 142aR1 and cathode pillar 140cB described below. The anode pillar 142aR1 (FIG. 18) is formed on the contact metal 146aPL2B (+Z direction side) and integrated with the contact metal 146aPL2B. The cathode pillar 140cB (FIG. 17) is formed on the contact metal 146cB (+Z direction side) and integrated with the contact metal 146cB. The anode pillar 142aG has its +Z direction surface (hereinafter also referred to as the anode pillar upper surface 142aGS1) exposed from the transparent insulating material 128B. The anode pillar 142aG has its -Z direction surface (the anode pillar lower surface 142aGS2) exposed from the underlying transparent insulating material 126B.

[0165] The anode pillar 142aR1 (FIG. 18) is made of a conductive material, similar to the anode pillar 142aG, and is disposed opposite the connection pad 112R of the circuit board 110 in the Z direction, constituting part of the vertical wiring 122R. The anode pillar 142aR1 has its +Z-direction surface (hereinafter also referred to as the anode pillar upper surface 142aR1S1) exposed from the transparent insulating material 128B. The anode pillar 142aR1 also has its -Z-direction surface (the anode pillar lower surface 142aR1S2) exposed from the underlying transparent insulating material 126B.

[0166] The anode pad 144B (FIG. 18) is made of a conductive material similar to the anode pillar 142aG, and is disposed opposite the connection pad 112B of the circuit board 110 in the Z direction to form the vertical wiring 122B. The surface of this anode pad 144B on the −Z direction side (anode pad surface 144BS) is exposed from the underlying transparent insulating material 126B.

[0167] The cathode pillar 140cB (FIG. 17) is made of a conductive material similar to the anode pillar 142aG, is disposed opposite the connection pad 112C of the circuit board 110 in the Z direction, and constitutes part of the vertical wiring 122C. The cathode pillar 140cB has its +Z direction surface (hereinafter also referred to as the cathode pillar upper surface 140cBS1) exposed from the transparent insulating material 128B. The cathode pillar 140cB has its -Z direction surface (hereinafter also referred to as the cathode pillar lower surface 140cBS2) exposed from the underlying transparent insulating material 126B.

[0168] The transparent insulating material 128B is made of, for example, the same material as the underlying transparent insulating material 126B, and has sufficient insulating properties and is transparent to at least the wavelength of light emitted by the thin-film LEDs 30B. This transparent insulating material 128B is arranged to cover the underlying transparent insulating material 126B, the thin-film LED 30B, the anode electrode 32B, the cathode electrode 34B, the lead-out wiring 136aB and 136cB, the interlayer insulating film 138aB and 138cB, and the anode pad 144B from the +Z direction side, excluding the anode pillars 142aG and 142aR1 and the cathode pillar 140cB, and these thin-film LED 30B, the anode electrode 32B, the cathode electrode 34B, the lead-out wiring 136aB and 136cB, the interlayer insulating film 138aB and 138cB, and the anode pad 144B are embedded inside between the underlying transparent insulating material 126B.

[0169] This transparent insulating material 128B (Figure 17) has a transparent insulating material opening 150aG formed on the +Z direction side of the underlying transparent insulating material opening 148aG, which penetrates the transparent insulating material 128B in the Z direction (light emitting direction De) from the surface (upper surface) on the +Z direction side of the transparent insulating material 128B (hereinafter also referred to as the transparent insulating material surface 128BS) to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 148aG).

[0170] Furthermore, the transparent insulating material 128B (Figure 18) has a transparent insulating material opening 150aR1 formed on the +Z direction side of the underlying transparent insulating material opening 148aR1, which penetrates the transparent insulating material 128B in the Z direction (light emitting direction De) from the transparent insulating material surface 128BS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 148aR1).

[0171] Furthermore, the transparent insulating material 128B (Figure 17) has a transparent insulating material opening 150cB formed on the +Z direction side of the underlying transparent insulating material opening 148cB, which penetrates the transparent insulating material 128B in the Z direction (light emitting direction De) from the transparent insulating material surface 128BS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 148cB).

[0172] The base transparent insulating material opening 148aG and the transparent insulating material opening 150aG form a first thin film layer opening 152aG. The first thin film layer opening 152aG is formed from the upper surface of the first thin film layer 120B on the +Z direction side (hereinafter also referred to as the first thin film layer upper surface 120BS1) to the lower surface on the -Z direction side (the first thin film layer lower surface 120BS2), and an anode pillar 142aG is formed therein. The base transparent insulating material opening 148aR1 and the transparent insulating material opening 150aR1 form a first thin film layer opening 152aR1. The first thin film layer opening 152aR1 is formed from the first thin film layer upper surface 120BS1 to the first thin film layer lower surface 120BS2, and an anode pillar 142aR1 is formed therein. Furthermore, the base transparent insulating material opening 148cB and the transparent insulating material opening 150cB form a first thin film layer opening 152cB. The first thin film layer opening 152cB is formed from the first thin film layer upper surface 120BS1 to the first thin film layer lower surface 120BS2, and has a cathode pillar 140cB formed therein.

[0173] Furthermore, the first thin film layer 120B has a first thin film layer upper surface 120BS1 formed as an extremely flat plane. That is, in the first thin film layer 120B, the transparent insulating material surface 128BS, the anode pillar upper surfaces 142aGS1 and 142aR1S1, and the cathode pillar upper surface 140cBS1 are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the transparent insulating material surface 128BS, the anode pillar upper surface 142aGS1, the anode pillar upper surface 142aR1S1, and the cathode pillar upper surface 140cBS1 are all located on the same plane.

[0174] Specifically, in the first thin film layer 120B, the surface roughness of the first thin film layer upper surface 120BS1, i.e., the surface roughness Rpv of the transparent insulating material surface 128BS, the anode pillar upper surface 142aGS1, the anode pillar upper surface 142aR1S1 and the cathode pillar upper surface 140cBS1, are all 10 nm or less.

[0175] Furthermore, the first thin film layer 120B has a first thin film layer lower surface 120BS2 formed as an extremely flat plane. That is, in the first thin film layer 120B, the lower surface 126BS2 of the underlying transparent insulating material, the lower surfaces 142aGS2 and 142aR1S2 of the anode pillars, the anode pad surface 144BS, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wirings 136aB and 136cB are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the lower surface 126BS2 of the underlying transparent insulating material, the lower surfaces 142aGS2 and 142aR1S2 of the anode pillars, the anode pad surface 144BS, and the lower surfaces of the lead-out wirings 136aB and 136cB are all located on the same plane.

[0176] Specifically, in the first thin film layer 120B, the surface roughness Rpv of the lower surface 120BS2 of the first thin film layer, i.e., the lower surface 126BS2 of the underlying transparent insulating material, the lower surfaces 142aGS2 and 142aR1S2 of the anode pillars, the anode pad surface 144BS, and the lower surfaces of the lead-out wirings 136aB and 136cB, are all 10 nm or less.

[0177] [2-4-2. Composition of the second thin film layer] As shown in Figures 17 and 18, and Figure 20, in which the same symbols are used for components corresponding to those in Figure 7, the second thin film layer 120G is composed of an underlying transparent insulating material 126G, a transparent insulating material 128G, a thin film LED 30G, an anode electrode 32G, a cathode electrode 34G, lead-out wiring 136aG and 136cG, interlayer insulating films 138aG and 138cG, an anode pillar 142aR2, an anode pad 144G, and a cathode pillar 140cG.

[0178] The underlying transparent insulating material 126G is made of the same material as the underlying transparent insulating material 126B, and is sufficiently insulating and transparent to at least the wavelength of light emitted by the thin-film LED 30G. The underlying transparent insulating material 126G extends from one end to the other end of the pixel section 108 in the AA cross-sectional direction Da (FIG. 17). However, underlying transparent insulating material openings 148G and 148cG are formed at locations facing the first thin-film layer openings 152aG and 152cG in the Z direction in the first thin-film layer 120B, respectively, penetrating the underlying transparent insulating material 126G in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 126G (hereinafter also referred to as the underlying transparent insulating material upper surface 126GS1) to the surface (lower surface) on the −Z direction side of the underlying transparent insulating material 126G (hereinafter also referred to as the underlying transparent insulating material lower surface 126GS2).

[0179] Furthermore, although the underlying transparent insulating material 126G extends from one end to the other end of the pixel section 108 in the BB cross-sectional direction Db (Figure 18), at a location opposite the first thin film layer opening 152aR1 in the Z direction in the first thin film layer 120B, an underlying transparent insulating material opening 148aR2 is formed that penetrates the underlying transparent insulating material 126G in the Z direction (light-emitting direction De) from the upper surface 126GS1 of the underlying transparent insulating material to the lower surface 126GS2 of the underlying transparent insulating material.

[0180] The thin-film LED 30G is a thin-film inorganic light-emitting element embedded in a transparent insulating material 128G. The thin-film LED 30G is disposed at the center of the pixel unit 108 in the AA cross-sectional direction Da, but is offset from the center of the pixel unit 108 toward the -X and +Y directions. The thin-film LED 30G has a length within a predetermined range in the AA cross-sectional direction Da and the BB cross-sectional direction Db, a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 128G. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30G, is a flat surface extending along the X and Y directions. The thin-film LED 30G is an LED that emits green light and is made of, for example, a GaP-based material. The anode electrode 32G is disposed on an anode formed at the center of the +Z direction side of the thin-film LED 30G. The cathode electrode 34G is disposed on a cathode formed on the -X and Y direction side of the +Z direction side of the thin-film LED 30G.

[0181] The lead-out wiring 136aG (FIG. 17) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32G facing the +Z direction and the anode pad 144G, electrically connecting them. The interlayer insulating film 138aG is made of an insulating material and is disposed between the lead-out wiring 136aG and the thin-film LED 30G, and is larger than the lead-out wiring 136aG when viewed along the Z direction. This interlayer insulating film 138aG protects unnecessary portions of the lead-out wiring 136aG and the thin-film LED 30G from short-circuiting.

[0182] The lead-out wiring 136cG (FIG. 17) is made of a conductive material similar to the lead-out wiring 136aG, and is in contact with the surface (upper surface) of the cathode electrode 34G facing the +Z direction and the cathode pillar 140cG, electrically connecting them. The interlayer insulating film 138cG is made of an insulating material similar to the interlayer insulating film 138aG, and is disposed between the lead-out wiring 136cG and the thin-film LED 30G, and is larger than the lead-out wiring 136cG when viewed along the Z direction. This interlayer insulating film 138cG protects unnecessary short circuits between the lead-out wiring 136cG and the thin-film LED 30G.

[0183] The above-mentioned anode electrode 32G, cathode electrode 34G, and lead-out wiring 136aG and 136cG are made of a transparent conductive material such as ITO, and it is desirable that the interlayer insulating films 138aG and 138cG are transparent to the wavelength of light emitted by the thin-film LEDs 30B and 30G.

[0184] The anode pillar 142aR2 (FIG. 18) is made of a conductive material such as gold, copper, or titanium. It is located opposite the anode pillar 142aR1 of the first thin film layer 120B in the Z direction and constitutes a part of the vertical wiring 122R. Specifically, the anode pillar 142aR2 is formed on (on the +Z direction side of) the contact metal 146aPLG, which is a gold-based metal for process stabilization, and is integrated with the contact metal 146aPLG. The anode pillar 142aR2 is also composed of a titanium barrier layer, which is a copper diffusion prevention film, formed on the contact metal 146aPLG, a copper seed metal formed on the barrier layer, and a copper plating portion grown and filled on the seed metal. The same applies to the cathode pillar 140cG (described later); the cathode pillar 140cG (FIG. 17) is formed on (on the +Z direction side of) the contact metal 146cG and is integrated with the contact metal 146cG. The anode pillar 142aR2 has its +Z surface (hereinafter also referred to as the anode pillar upper surface 142aR2S1) exposed from the transparent insulating material 128G, and its −Z surface (hereinafter also referred to as the anode pillar lower surface 142aR2S2) exposed from the underlying transparent insulating material 126G.

[0185] The anode pad 144G (FIG. 17) is made of a conductive material similar to the anode pillar 142aR2, and is disposed opposite the anode pillar 142aG of the first thin film layer 120B in the Z direction, constituting part of the vertical wiring 122G. The surface of this anode pad 144G on the -Z direction side (hereinafter also referred to as the anode pad surface 144GS) is exposed from the underlying transparent insulating material 126G.

[0186] The cathode pillar 140cG (FIG. 17) is made of a conductive material similar to the anode pillar 142aR2, is disposed opposite the cathode pillar 140cB of the first thin film layer 120B in the Z direction, and constitutes a part of the vertical wiring 122C. The cathode pillar 140cG has its +Z direction surface (hereinafter also referred to as the cathode pillar upper surface 140cGS1) exposed from the transparent insulating material 128G. The cathode pillar 140cG has its -Z direction surface (hereinafter also referred to as the cathode pillar lower surface 140cGS2) exposed from the underlying transparent insulating material 126G.

[0187] The transparent insulating material 128G is made of, for example, the same material as the underlying transparent insulating material 126G, and has sufficient insulating properties and is transparent to at least the wavelength of light emitted by the thin-film LEDs 30B and 30G. This transparent insulating material 128G is arranged to cover the underlying transparent insulating material 126G, thin-film LED 30G, anode electrode 32G, cathode electrode 34G, lead-out wiring 136aG and 136cG, interlayer insulating film 138aG and 138cG, and anode pad 144G from the +Z direction side, excluding anode pillar 142aR2 and cathode pillar 140cG, and these thin-film LED 30G, anode electrode 32G, cathode electrode 34G, lead-out wiring 136aG and 136cG, interlayer insulating film 138aG and 138cG, and anode pad 144G are embedded inside between the underlying transparent insulating material 126G.

[0188] This transparent insulating material 128G (Figure 18) has a transparent insulating material opening 150aR2 formed on the +Z direction side of the underlying transparent insulating material opening 148aR2, which penetrates the transparent insulating material 128G in the Z direction (light emitting direction De) from the surface (upper surface) on the +Z direction side of the transparent insulating material 128G (hereinafter also referred to as the transparent insulating material surface 128GS) to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 148aR2).

[0189] Furthermore, the transparent insulating material 128G (Figure 17) has a transparent insulating material opening 150cG formed on the +Z direction side of the underlying transparent insulating material opening 148cG, which penetrates the transparent insulating material 128G in the Z direction (light emitting direction De) from the transparent insulating material surface 128GS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 148cG).

[0190] The base transparent insulating material opening 148aR2 and the transparent insulating material opening 150aR2 form a second thin film layer opening 152aR2. The second thin film layer opening 152aR2 is formed from the upper surface of the second thin film layer 120G on the +Z direction side (hereinafter also referred to as the second thin film layer upper surface 120GS1) to the lower surface on the -Z direction side (hereinafter also referred to as the second thin film layer lower surface 120GS2), and an anode pillar 142aR2 is formed therein. The base transparent insulating material opening 148cG and the transparent insulating material opening 150cG form a second thin film layer opening 152cG. The second thin film layer opening 152cG is formed from the second thin film layer upper surface 120GS1 to the second thin film layer lower surface 120GS2, and a cathode pillar 140cG is formed therein.

[0191] Furthermore, the second thin film layer 120G has a second thin film layer upper surface 120GS1 formed in an extremely flat plane. That is, in the second thin film layer 120G, the transparent insulating material surface 128GS, the anode pillar upper surface 142aR2S1, and the cathode pillar upper surface 140cGS1 are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the transparent insulating material surface 128GS, the anode pillar upper surface 142aR2S1, and the cathode pillar upper surface 140cGS1 are all located on the same plane.

[0192] Specifically, in the second thin film layer 120G, the surface roughness Gpv of the second thin film layer upper surface 120GS1, that is, the surface roughness Gpv of the transparent insulating material surface 128GS, the anode pillar upper surface 142aR2S1, and the cathode pillar upper surface 140cGS1, is all 10 nm or less.

[0193] Furthermore, the second thin film layer 120G has a second thin film layer lower surface 120GS2 formed as an extremely flat plane. That is, in the second thin film layer 120G, the lower surface 126GS2 of the underlying transparent insulating material, the lower surface 142aR2S2 of the anode pillar, the anode pad surface 144GS, the lower surface 140cGS2 of the cathode pillar, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wirings 136aG and 136cG are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the lower surface 126GS2 of the underlying transparent insulating material, the lower surface 142aR2S2 of the anode pillar, the anode pad surface 144GS, the lower surface 140cGS2 of the cathode pillar, and the lower surfaces of the lead-out wirings 136aG and 136cG are all located on the same plane.

[0194] Specifically, in the second thin film layer 120G, the surface roughness of the lower surface 120GS2 of the second thin film layer, i.e., the surface roughness Gpv of the lower surface 126GS2 of the underlying transparent insulating material, the lower surface 142aR2S2 of the anode pillar, the anode pad surface 144GS, the lower surface 140cGS2 of the cathode pillar, and the lower surfaces of the lead-out wiring 136aG and 136cG are all 10 nm or less.

[0195] [2-4-3. Composition of the third thin film layer] As shown in Figures 17 and 18, and Figure 21 in which the same symbols are used for components corresponding to Figure 8, the third thin film layer 120R is composed of an underlying transparent insulating material 126R, a transparent insulating material 128R, a thin film LED 30R, an anode electrode 32R, a cathode electrode 134R, an extraction wiring 136aR, an interlayer insulating film 138aR, and an anode pad 144R.

[0196] The underlying transparent insulating material 126R is made of the same material as the underlying transparent insulating material 126B, and is sufficiently insulating while being transparent to at least the wavelength of light emitted by the thin-film LEDs 30B, 30G, and 30R. This underlying transparent insulating material 126R extends from one end to the other end of the pixel section 108 in the AA cross-sectional direction Da (FIG. 4). However, at a location facing the second thin-film layer opening 152cG in the Z direction in the second thin-film layer 120G, an underlying transparent insulating material opening 148cR is formed, which penetrates the underlying transparent insulating material 126R in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 126R (hereinafter also referred to as the underlying transparent insulating material upper surface 126RS1) to the surface (lower surface) on the −Z direction side (hereinafter also referred to as the underlying transparent insulating material lower surface 126RS2). The underlying transparent insulating material opening 148cR has the cathode electrode 134R formed therein. The underlying transparent insulating material opening 148cR is formed larger than the underlying transparent insulating material opening 48cR (FIG. 5) in the XY directions.

[0197] Furthermore, although the underlying transparent insulating material 126R extends from one end to the other end of the pixel section 108 in the BB cross-sectional direction Db (Figure 5), at a location opposite the second thin film layer opening 152aR2 in the Z direction in the second thin film layer 120G, an underlying transparent insulating material opening 148R is formed that penetrates the underlying transparent insulating material 126R in the Z direction (light-emitting direction De) from the upper surface 126RS1 of the underlying transparent insulating material to the lower surface 126RS2 of the underlying transparent insulating material.

[0198] The thin-film LED 30R is a thin-film inorganic light-emitting element embedded in a transparent insulating material 128R. The thin-film LED 30R is disposed at the center of the pixel unit 108 in the BB cross-sectional direction Db, but is offset from the center of the pixel unit 108 toward the -XY direction. The thin-film LED 30R has a predetermined length in the AA cross-sectional direction Da and the BB cross-sectional direction Db, a thickness in the Z direction of 3 μm or less, and is embedded in the transparent insulating material 128R. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30R, is a flat surface extending along the XY direction. The thin-film LED 30R is a quaternary LED that emits red light and is made of a III-V compound semiconductor material, such as a GaAs-based material. The anode electrode 32R is disposed on an anode formed at the center of the +Z direction side of the thin-film LED 30R. The cathode electrode 134R is disposed on a cathode formed on the -XY direction side of the -Z direction side of the thin-film LED 30R.

[0199] The lead-out wiring 136aR (FIG. 5) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32R on the +Z direction side and the anode pad 144R, respectively, to electrically connect them. The interlayer insulating film 138aR is made of an insulating material and is disposed between the lead-out wiring 136aR and the thin-film LED 30R, and is formed to be larger than the lead-out wiring 136aR when viewed along the Z direction. This interlayer insulating film 138aR protects unnecessary short circuits between the lead-out wiring 136aR and the thin-film LED 30R.

[0200] The cathode electrode 134R is disposed opposite the cathode pillar 140cG of the second thin film layer 120G in the Z direction, and constitutes a part of the vertical wiring 122C. The cathode electrode 134R is formed larger in the XY directions than the cathode electrode 34R (FIG. 8). The surface of the cathode electrode 134R on the -Z direction side (hereinafter also referred to as the cathode electrode surface 134RS) is exposed from the underlying transparent insulating material 126R.

[0201] The above-mentioned anode electrode 32R, cathode electrode 134R and lead-out wiring 136aR are made of a transparent conductive material such as ITO, and the interlayer insulating film 138aR is preferably transparent to the wavelength of light emitted by the thin-film LEDs 30B, 30G and 30R.

[0202] The anode pad 144R (FIG. 8) is made of a conductive material such as gold, copper, or titanium, and is disposed opposite the anode pillar 142aR2 of the second thin film layer 120G in the Z direction, constituting part of the vertical wiring 122R. The surface of this anode pad 144R on the -Z direction side (hereinafter also referred to as the anode pad surface 144RS) is exposed from the underlying transparent insulating material 126R.

[0203] The transparent insulating material 128R is made of, for example, the same material as the underlying transparent insulating material 126R, and has sufficient insulating properties while being transparent to at least the wavelengths of light emitted by the thin-film LEDs 30B, 30G, and 30R. The transparent insulating material 128R is disposed so as to cover the underlying transparent insulating material 126R, thin-film LED 30R, anode electrode 32R, cathode electrode 134R, lead-out wiring 136aR, interlayer insulating film 138aR, and anode pad 144R from the +Z direction side, and embeds the thin-film LED 30R, anode electrode 32R, cathode electrode 134R, lead-out wiring 136aR, interlayer insulating film 138aR, and anode pad 144R between itself and the underlying transparent insulating material 126R.

[0204] Furthermore, the third thin film layer 120R has a third thin film layer lower surface 120RS2 formed in an extremely flat plane. That is, in the third thin film layer 120R, the underlying transparent insulating material lower surface 126RS2, the anode pad surface 144RS, the cathode electrode surface 134RS, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wiring 136aR are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the underlying transparent insulating material lower surface 126RS2, the anode pad surface 144RS, the cathode electrode surface 134RS, and the lower surfaces of the lead-out wiring 136aR are all located on the same plane.

[0205] Specifically, in the third thin film layer 120R, the surface roughness of the third thin film layer lower surface 120RS2, i.e., the surface roughness Ppv of the underlying transparent insulating material lower surface 126RS2, the anode pad surface 144RS, the cathode electrode surface 134RS, and the lower surface of the lead-out wiring 136aR, are all 10 nm or less. In the following, the lead-out wirings 136aB, 136aG, 136aR, 136cB, and 136cG are also collectively referred to as lead-out wirings 136.

[0206] [2-5. Connection between thin film layers and circuit boards] [2-5-1. Physical connection relationship between circuit board and thin film layer] The substrate surface 10S of the circuit substrate 110 and the first thin film layer lower surface 120BS2 of the first thin film layer 120B are physically bonded by intermolecular forces. The first thin film layer upper surface 120BS1 of the first thin film layer 120B and the second thin film layer lower surface 120GS2 of the second thin film layer 120G are also physically bonded by intermolecular forces. The second thin film layer upper surface 120GS1 of the second thin film layer 120G and the third thin film layer lower surface 120RS2 of the third thin film layer 120R are also physically bonded by intermolecular forces.

[0207] In this way, in the LED display unit 102, the substrate surface 10S and the lower surface 120BS2 of the first thin film layer, the upper surface 120BS1 and the lower surface 120GS2 of the second thin film layer, and the upper surface 120GS1 and the lower surface 120RS2 of the third thin film layer are bonded by intermolecular forces rather than by metal bonding.

[0208] [2-5-2. Electrical connection between circuit board and thin film layer] The connection pad 112B (FIG. 18) has a connection pad surface 112BS physically bonded to the anode pad surface 144BS of the anode pad 144B of the first thin-film layer 120B by intermolecular forces, and is electrically connected to the anode electrode 32B of the thin-film LED 30B via the anode pad 144B and the lead-out wiring 136aB, like the conductive path Rba.

[0209] The connection pad surface 112GS of the connection pad 112G (FIG. 17) is physically bonded by intermolecular forces to the anode pillar lower surface 142aGS2 of the anode pillar 142aG of the first thin-film layer 120B. The anode pillar upper surface 142aGS1 of the anode pillar 142aG is physically bonded by intermolecular forces to the anode pad surface 144GS of the anode pad 144G of the second thin-film layer 120G. The anode pad 144G is in physical contact with the lead-out wiring 136aG. Therefore, the connection pad 112G is electrically connected to the anode electrode 32G of the thin-film LED 30G via the anode pillar 142aG, the anode pad 144G, and the lead-out wiring 136aG, as in the conductive path Rga.

[0210] The connection pad surface 112RS of the connection pad 112R (FIG. 18) is physically bonded by intermolecular force to the anode pillar lower surface 142aR1S2 of the anode pillar 142aR1 of the first thin film layer 120B. The anode pillar upper surface 142aR1S1 of the anode pillar 142aR1 is physically bonded by intermolecular force to the anode pillar lower surface 142aR2S2 of the anode pillar 142aR2 of the second thin film layer 120G. The anode pillar upper surface 142aR2S1 of the anode pillar 142aR2 is physically bonded by intermolecular force to the anode pad surface 144RS of the anode pad 144R of the third thin film layer 120R. The anode pad 144R is in physical contact with the lead-out wiring 136aR. Therefore, the connection pad 112R is electrically connected to the anode electrode 32R of the thin-film LED 30R via the anode pillar 142aR1, the anode pillar 142aR2, the anode pad 144R, and the lead-out wiring 136aR, like the conductive path Rra.

[0211] The connection pad 112C (FIG. 17) has a connection pad surface 112CS physically bonded to a cathode pillar lower surface 140cGS2 of the cathode pillar 140cG of the first thin-film layer 120B by intermolecular forces. The cathode pillar 140cG has a cathode pillar upper surface 140cGS1 physically bonded to a cathode pillar lower surface 140cGS2 of the cathode pillar 140cG of the second thin-film layer 120G by intermolecular forces. The cathode pillar 140cG has a cathode pillar upper surface 140cGS1 physically bonded to a cathode electrode surface 134RS of the cathode electrode 134R of the third thin-film layer 120R by intermolecular forces. The cathode electrode 134R is in physical contact with the thin-film LED 30R. Therefore, the cathode electrode 134R is electrically connected to the cathode common wiring of the wiring layer 16 via the cathode pillar 140cG, the contact metal 146cG, the cathode pillar 140cB, the contact metal 146cB, and the connection pad 112C, like the conductive path Rc.

[0212] The lead wiring 136cG is in physical contact with the contact metal 146cG. Therefore, the cathode electrode 134G is electrically connected to the cathode common wiring of the wiring layer 16 via the lead wiring 136cG, the contact metal 146cG, the cathode pillar 140cB, the contact metal 146cB, and the connection pad 112C, like the conductive path Rc.

[0213] Furthermore, the lead-out wiring 136cB is in physical contact with the contact metal 146cB. Therefore, the cathode electrode 134B is electrically connected to the cathode common wiring of the wiring layer 16 via the lead-out wiring 136cB, the contact metal 146cB, and the connection pad 112C, like the conductive path Rc. The cathode common wiring is also electrically connected to the vertical wiring 122C of other pixel units 108, and is also connected to a common cathode connection terminal (common terminal) of the driving driver 6.

[0214] [2-6. LED display display manufacturing method] Next, an example of a manufacturing method for the LED display unit 102 of the LED display device 101 will be described with reference to Figures 22, 23, 24, and 25, in which the same reference numerals are used to designate components corresponding to those in Figures 9, 10, 11, and 12, respectively. Incidentally, Figures 22, 23, 24, and 25 are all schematic cross-sectional views showing a state in which the +Z direction faces upward. For convenience of explanation, the +Z direction will also be referred to as the upward direction, and the -Z direction will also be referred to as the downward direction.

[0215] [2-6-1. Manufacturing method of the first thin film layer] First, a manufacturing method of the first thin film layer 120B will be described with reference to Fig. 22. First, as shown in Fig. 22(A), the manufacturing apparatus 60 performs a step of growing a thin film LED layer 166B on the upper side, i.e., the +Z direction side, of a predetermined LED growth substrate 162B. In this embodiment, a sapphire substrate is used as an example of the LED growth substrate 162B.

[0216] 22(B), the manufacturing apparatus 60 separates the thin-film LED layer 166B from the LED growth substrate 162B by a known laser lift-off method. It is desirable to flatten the separated surface of the thin-film LED layer 166B by polishing or the like.

[0217] 22(C), the manufacturing apparatus 60 sequentially deposits a sacrificial layer 170B and a base transparent insulating material 126B on the formation substrate 168B of the first thin film layer 120B, and bonds the thin film LED layer 166B to the base transparent insulating material 126B by intermolecular forces. At this time, the top surfaces (side surfaces in the +Z direction) of the sacrificial layer 170B and the base transparent insulating material 126B need to be flat to Rpv=10 [nm] or less, so the manufacturing apparatus 60 may perform a smoothing process such as polishing.

[0218] Next, as shown in Figure 22(D), the manufacturing equipment 60 forms the thin-film LED 30B by etching the thin-film LED layer 166B through an etching process, and also patterns the underlying transparent insulating material openings 148aG, 148cB, 148aR1 (Figure 18) and 148B (Figure 18) in the underlying transparent insulating material 126B.

[0219] Next, as shown in FIG. 22(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32B, a cathode electrode 34B, interlayer insulating films 138cB and 138aB (FIG. 18), lead-out wiring 136cB and 136aB, and contact metals 146aPL1B, 146cB, 146aPL2B (FIG. 18), and 146aPDB (FIG. 18) on the thin-film LED 30B and the underlying transparent insulating material 126B.

[0220] Next, as shown in FIG. 22(F), the manufacturing equipment 60 fills the transparent insulating material 128B and patterns the transparent insulating material 128B to form transparent insulating material openings 150aG, 150cB, and 150aR1 (FIG. 18). Then, by plating, the manufacturing equipment 60 forms the anode pillar 142aG, the cathode pillar 140cB, and the anode pillar 142aR1 (FIG. 18) on the contact metals 146aPL1B, 146cB, and 146aPL2B (FIG. 18) exposed from the transparent insulating material openings 150aG, 150cB, and 150aR1 (FIG. 18). The contact metal 146aPDB (FIG. 18) becomes the anode pad 144B.

[0221] Next, as shown in FIG. 22(G), the manufacturing equipment 60 performs a planarization process using chemical mechanical polishing (CMP) to planarize the upper surfaces of the transparent insulating material 128B, the anode pillar 142aG, the cathode pillar 140cB, and the anode pillar 142aR1 (FIG. 18), thereby forming anode pillar upper surfaces 142aGS1 and 142aR1S1 (FIG. 5) on the upper surfaces of the anode pillars 142aG and 142aR1 (FIG. 18), respectively, and a cathode pillar upper surface 140cBS1 on the upper surface of the cathode pillar 140cB, so that they are exposed from the upper surface of the transparent insulating material 128B.

[0222] [2-6-2. Manufacturing method of second thin film layer] Next, a manufacturing method of the second thin film layer 120G will be described with reference to Fig. 23. First, as shown in Fig. 23(A), the manufacturing apparatus 60 performs a step of growing a thin film LED layer 166G on the upper side, i.e., the +Z direction side, of a predetermined LED growth substrate 162G. In this embodiment, a sapphire substrate is used as an example of the LED growth substrate 162G.

[0223] 23(B), the manufacturing apparatus 60 separates the thin-film LED layer 166G from the LED growth substrate 162G by a known laser lift-off method. It is desirable to flatten the separated surface of the thin-film LED layer 166G by polishing or the like.

[0224] 23(C), the manufacturing apparatus 60 sequentially deposits a sacrificial layer 170G and an underlying transparent insulating material 126G on a formation substrate 168G for the second thin film layer 120G, and bonds the thin film LED layer 166G to the underlying transparent insulating material 126G by intermolecular forces. At this time, the upper surfaces (side surfaces in the +Z direction) of the sacrificial layer 170G and the underlying transparent insulating material 126G need to be flat to Rpv=10 [nm] or less, so the manufacturing apparatus 60 may perform a smoothing process such as polishing.

[0225] Next, as shown in Figure 23(D), the manufacturing equipment 60 forms thin-film LEDs 30G by etching the thin-film LED layer 166G through an etching process, and also patterns the underlying transparent insulating material openings 148G, 148cG, and 148aR2 (Figure 18) in the underlying transparent insulating material 126G.

[0226] Next, as shown in FIG. 23(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32G, a cathode electrode 34G, interlayer insulating films 138cG and 138aG, lead wiring 136cG and 136aG, and contact metals 146aPDG, 146cG, and 146aPLG (FIG. 18) on the thin-film LED 30G and the underlying transparent insulating material 126G.

[0227] Next, as shown in Fig. 23(F), the manufacturing equipment 60 fills the transparent insulating material 128G with transparent insulating material 128G, patterns the transparent insulating material openings 150cG and 150aR2 (Fig. 18), and then forms the cathode pillar 140cG and the anode pillar 142aR2 (Fig. 18) on the contact metals 146cG and 146aPLG (Fig. 18) exposed from the transparent insulating material openings 150cG and 150aR2 (Fig. 18) by plating. The contact metal 146aPDG becomes the anode pad 144G.

[0228] Next, as shown in FIG. 23(G), the manufacturing equipment 60 performs a planarization process using chemical mechanical polishing (CMP) to planarize the upper surfaces of the transparent insulating material 128G, the cathode pillar 140cG, and the anode pillar 142aR2 (FIG. 18), thereby forming a cathode pillar upper surface 140cGS1 and an anode pillar upper surface 142aR2S1 on the upper surfaces of the cathode pillar 140cG and the anode pillar 142aR2 (FIG. 18), respectively, so that they are exposed from the upper surface of the transparent insulating material 128G.

[0229] [2-6-3. Manufacturing method of the third thin film layer] Next, a manufacturing method of the third thin-film layer 120R will be described with reference to Fig. 24. First, as shown in Fig. 24(A), the manufacturing apparatus 60 performs a process of forming a lattice-matched sacrificial layer 164R on the upper side of a predetermined LED growth substrate 162R, i.e., on the +Z direction side, and then growing a thin-film LED layer 166R on the upper side. In this embodiment, as an example, GaAs is used as the LED growth substrate 162R, and a material such as GaAs containing Al is used as the sacrificial layer 164R.

[0230] 24(B), the manufacturing apparatus 60 separates the thin-film LED layer 166R from the LED growth substrate 162R by etching and removing the sacrificial layer 164R by an etching process. It is desirable to flatten the separated thin-film LED layer 166R by polishing the separated surface or the like.

[0231] Next, as shown in Figure 24(C), the manufacturing equipment 60 sequentially deposits a sacrificial layer 170R and an underlying transparent insulating material 126R on the formation substrate 168R of the third thin film layer 120R, and then performs an etching process to pattern underlying transparent insulating material openings 148cR and 148G (Figure 18) in the underlying transparent insulating material 126R.

[0232] Next, as shown in FIG. 24(D), the manufacturing equipment 60 forms the cathode electrode 134R in the underlying transparent insulating material opening 148cR by plating.

[0233] 24(E), the manufacturing equipment 60 performs a planarization process by chemical mechanical polishing (CMP) to planarize the upper surfaces of the underlying transparent insulating material 126R and the cathode electrode 134R, thereby exposing the upper surface of the cathode electrode 134R from the upper surface of the transparent insulating material 128R. Subsequently, the manufacturing equipment 60 bonds the thin-film LED layer 166R to the underlying transparent insulating material 126R by intermolecular forces.

[0234] Next, as shown in FIG. 24(F), the manufacturing equipment 60 performs an etching process on the thin-film LED layer 166R to form thin-film LEDs 30R and pattern underlying transparent insulating material openings 148R (FIG. 18) in the underlying transparent insulating material 126R.

[0235] Next, as shown in Fig. 24(G), the manufacturing equipment 60 performs a patterning process using techniques such as lithography and sputtering to form an anode electrode 32R, an interlayer insulating film 138aR (Fig. 18), an extraction wiring 136aR, and a contact metal 146aPDR (Fig. 18) on the thin-film LED 30R and the underlying transparent insulating material 126R. The contact metal 146aPDR (Fig. 18) becomes an anode pad 144R.

[0236] Next, the manufacturing equipment 60 fills in the transparent insulating material 128R as shown in Fig. 24(H). The manufacturing equipment 60 may perform a planarization process using chemical mechanical polishing (CMP) to flatten the upper surface of the transparent insulating material 128R.

[0237] [2-6-4.Layered joining process] Next, the process of laminating and bonding the first thin film layer 120B, the second thin film layer 120G, and the third thin film layer 120R manufactured by the above-mentioned manufacturing method onto the circuit board 110 will be described with reference to Figure 25, in which the same symbols are used for components corresponding to those in Figure 12.

[0238] First, as shown in FIG. 25(A), the manufacturing equipment 60 separates the first thin film layer 120B from the formation substrate 168B by etching and removing the sacrificial layer 170B (FIG. 22) by etching. As a result, the anode pillar lower surface 142aGS2, the cathode pillar lower surface 140cBS2, the anode pillar lower surface 142aR1S2 (FIG. 18), and the anode pad surface 144BS (FIG. 18) are exposed from the lower surface 126BS2 of the underlying transparent insulating material. The anode pillar lower surface 142aGS2, the cathode pillar lower surface 140cBS2, the anode pillar lower surface 142aR1S2 (FIG. 18), and the anode pad surface 144BS (FIG. 18) are formed flat on the same plane as the upper surface of the sacrificial layer 170B (FIG. 22). Next, the manufacturing equipment 60 bonds the separated first thin film layer 120B to the upper surface of the circuit board 110 by intermolecular forces using a known bonding method.

[0239] Next, as shown in FIG. 25(B), the manufacturing equipment 60 separates the second thin film layer 120G from the formation substrate 168G by etching and removing the sacrificial layer 170G (FIG. 23). This exposes the cathode pillar lower surface 140cGS2, the anode pad surface 144GS, and the anode pillar lower surface 142aR2S2 (FIG. 18) from the lower surface 126GS2 of the underlying transparent insulating material. The cathode pillar lower surface 140cGS2, the anode pad surface 144GS, and the anode pillar lower surface 142aR2S2 (FIG. 18) are formed flat and flush with the upper surface of the sacrificial layer 170G (FIG. 22). Next, the manufacturing equipment 60 bonds the separated second thin film layer 120G to the upper surface of the first thin film layer 120B, which was bonded to the circuit substrate 110 in FIG. 25(A), using a known bonding method through intermolecular forces.

[0240] Next, as shown in FIG. 25(C), the manufacturing equipment 60 separates the third thin film layer 120R from the formation substrate 168R by etching and removing the sacrificial layer 170R (FIG. 24). This exposes the cathode electrode surface 134RS and the anode pad surface 144RS (FIG. 18) from the lower surface 126RS2 of the underlying transparent insulating material. The cathode electrode surface 134RS and the anode pad surface 144RS (FIG. 18) are formed flat and flush with the upper surface of the sacrificial layer 170R (FIG. 24). Next, the manufacturing equipment 60 bonds the separated third thin film layer 120R to the upper surface of the second thin film layer 120G, which was bonded to the first thin film layer 120B in FIG. 25(B), using intermolecular forces by a known bonding method.

[0241] [2-7. LED display illumination] 26 and 27, when the LED display unit 102 emits light, the blue light LB emitted toward the second thin-film layer 120G is absorbed by the thin-film LED 30G because the thin-film LED 30G is made of a GaP substrate and absorbs wavelengths shorter than 564 nm (green), which corresponds to Eg = 2.2 eV. Furthermore, the blue light LB emitted toward the third thin-film layer 120R is absorbed by the thin-film LED 30R because the thin-film LED 30R is made of a GaAs substrate and absorbs wavelengths shorter than 660 nm (red), which corresponds to Eg = 1.9 eV. Furthermore, the blue light LB emitted toward the third thin-film layer 120R is reflected by the cathode electrode 134R. On the other hand, since the areas of the second thin film layer 120G other than the thin film LED 30G and the areas of the third thin film layer 120R other than the thin film LED 30R are transparent to the wavelength of blue light LB, blue light LB passes through the areas of the second thin film layer 120G other than the thin film LED 30G and the areas of the third thin film layer 120R other than the thin film LED 30R.

[0242] Furthermore, because the thin-film LED 30R is made of a GaAs substrate and absorbs wavelengths shorter than 660 nm (red), which corresponds to Eg = 1.9 eV, the green light LG emitted toward the third thin-film layer 120R is absorbed by the thin-film LED 30R. Furthermore, the green light LG emitted toward the third thin-film layer 120R is reflected by the cathode electrode 134R. On the other hand, the portions of the third thin-film layer 120R other than the thin-film LED 30R and the cathode electrode 134R are transparent to the wavelength of the green light LG, so the green light LG passes through the portions of the third thin-film layer 120R other than the thin-film LED 30R and the cathode electrode 134R.

[0243] Furthermore, the portions of the third thin-film layer 120R other than the thin-film LED 30R are transparent to the wavelength of the red light LR emitted from the thin-film LED 30R, so the red light LR passes through the portions of the third thin-film layer 120R other than the thin-film LED 30R.

[0244] In the pixel unit 108 according to the present embodiment, the thin-film LED 30G is arranged with its center displaced toward the +Y direction (i.e., offset) with respect to the center of the thin-film LED 30R. As a result, the third thin-film layer 120R absorbs part of the green light LG that is directed toward the thin-film LED 30R and reflects part of the green light that is directed toward the cathode electrode 134R by the thin-film LED 30R, but transmits part of the green light LG that is directed toward portions other than the thin-film LED 30R and the cathode electrode 134R and directs it in the +Z direction.

[0245] In the pixel unit 108, the thin-film LED 30B is arranged with its center displaced in the +X+Y direction relative to the center of the thin-film LED 30R and in the +XY direction relative to the center of the thin-film LED 30G (i.e., offset). Therefore, the third thin-film layer 120R and the second thin-film layer 120G absorb a portion of the blue light LB that is directed toward the thin-film LED 30R or 30G, and reflect a portion of the blue light that is directed toward the cathode electrode 134R, but transmit the blue light LB that is directed toward portions other than the thin-film LEDs 30R and 30G and the cathode electrode 134R, directing it in the +Z direction.

[0246] 26 and 27, members other than those necessary for the explanation are omitted as appropriate for the sake of convenience.

[0247] [2-8. Overlapping of thin film layers] Here, when the pixel unit 108 is viewed from the +Z direction along the light-emitting direction De, as shown in FIG. 28(A) in which the same reference numerals as in FIG. 14(A) are used to denote the components corresponding to those in FIG. 14(A), the hatched region where the thin-film LED 30R located furthest in the +Z direction overlaps with both the thin-film LED 30G and the thin-film LED 30B located further in the -Z direction than the thin-film LED 30R is called the light-absorbing region ARa. When the pixel unit 108 is viewed from the +Z direction along the light-emitting direction De, as shown in FIG. 28(B) in which the same reference numerals as in FIG. 14(B) are used to denote the components corresponding to those in FIG. 14(B), the hatched region where the thin-film LED 30G and the thin-film LED 30B located further in the -Z direction than the thin-film LED 30R overlap is called the light-transmitting region ARt. In the pixel unit 108 according to the present embodiment, the thin-film LEDs 30B, 30G, and 30R are arranged such that the light-absorbing region ARa (FIG. 28(A)) is smaller than the light-transmitting region ARt (FIG. 28(B)).

[0248] [2-9.Effects] In the LED display device 101 according to the second embodiment, the thin-film LEDs 30B on the first thin-film layer 120B, the thin-film LEDs 30G on the second thin-film layer 120G, and the thin-film LEDs 30R on the third thin-film layer 120R are stacked in this order, so that the thin-film LEDs 30R are arranged on the top layer. In addition, the LED display device 101 is arranged so that the thin-film LEDs 30R, 30G, and 30B are offset from one another.

[0249] Therefore, compared to a case where the thin-film LEDs 30B, 30G, and 30R are arranged with their centers aligned, the LED display device 101 can move at least a portion of the thin-film LEDs 30G and 30R out of the path of the blue light LB heading in the +Z direction, thereby increasing the amount of blue light LB that is not absorbed by the thin-film LED 30R and emitted to the outside of the LED display device 101. Also, the LED display device 101 can move at least a portion of the thin-film LED 30R out of the path of the green light LG heading in the +Z direction, thereby increasing the amount of green light LG that is not absorbed by the thin-film LED 30R and emitted to the outside of the LED display device 101.

[0250] Furthermore, the LED display device 101 is provided with a cathode electrode 134R on the third thin-film layer 120R, closer to the circuit board 110 than the thin-film LED 30R, that electrically connects the thin-film LED 30R to the circuit board 110 and reflects the red light LR emitted by the thin-film LED 30R. Furthermore, the LED display device 101 has a larger cathode electrode 134R (FIG. 21) than the cathode electrode 34R (FIG. 8) of the LED display device 1. This allows the LED display device 101 to reflect the red light LR toward the +Z direction, compensating for the low luminous efficiency of the thin-film LED 30R and efficiently emitting the red light LR to the outside. The larger the cathode electrode 134R, the more red light LR it can reflect, but the more it reflects blue light LB and green light LG toward the -Z direction, preventing them from emitting toward the LED display device 101.

[0251] In addition, the LED display device 101 according to the second embodiment can achieve the same effects as the LED display device 1 according to the first embodiment.

[0252] 3. Third Embodiment [3-1. LED display device configuration] 1 and 29 in which the same reference numerals are used for the corresponding components in FIG. 2, an LED display device 201 according to the third embodiment is configured similarly to the LED display device 1 except that an LED display unit 202 differs from the LED display unit 2. The LED display unit 202 is a display device in which elements including inorganic light emitting diodes (LEDs) are arranged as pixels (one picture element) in a matrix on a circuit board 210 which is an active matrix circuit board.

[0253] [3-2. Overall configuration of the LED display] 31 and 32, in which the same reference numerals are used for components corresponding to those in FIGS. 4 and 5, the LED display unit 202 has a configuration in which a thin film layer group 218 consisting of three thin film layers, a first thin film layer 220B, a second thin film layer 220R, and a third thin film layer 220G, is stacked within a display area set on the surface (hereinafter also referred to as substrate surface 10S) on the +Z direction side of a flat circuit board 210. Hereinafter, the first thin film layer 220B, the second thin film layer 220R, and the third thin film layer 220G will also be collectively referred to as thin film layers 220. Each thin film layer 220 has a film shape in which light-emitting elements are arranged in a grid pattern, and the film size is the same as that of the thin film layer 20 according to the first embodiment.

[0254] The following describes the pixel section 208, which is a region for one pixel, of the circuit board 210 and the thin film layer group 218 in the LED display section 202. In the following, the reference numerals of the members related to the anode terminal are suffixed with "A," the reference numerals of the members related to the thin film LED 30B of the first thin film layer 220B are suffixed with "B," the reference numerals of the members related to the thin film LED 30R of the second thin film layer 220R are suffixed with "R," and the reference numerals of the members related to the thin film LED 30G of the third thin film layer 220G are suffixed with "G."

[0255] [3-3. Circuit board configuration] 30, 31, and 32, in which the same reference numerals are used to designate components corresponding to those in FIG. 3, the circuit board 210 is a CMOS backplane circuit board manufactured by a silicon process. Compared to the circuit board 10, the circuit board 210 according to the third embodiment has connection pads 212 (connection pads 212R, 212G, 212B, and 212A) and active elements 214 (active elements 214R, 214G, and 214B) that are different from the connection pads 12 (connection pads 12R, 12G, 12B, and 12C) and active elements 14 (active elements 14R, 14G, and 14B), but is otherwise configured similarly.

[0256] The connection pads 212 (connection pads 212R, 212G, 212B, and 212A) are arranged in a matrix (i.e., a grid) on the substrate surface 10S. Hereinafter, the connection pads 212R, 212G, 212B, and 212A will be collectively referred to as connection pads 212. This connection pad 212 corresponds to one pixel, and the four connection pads 212R, 212G, 212B, and 212A form a connection pad set 212T. The connection pad set 212T is arranged so that the light-emitting portion 224 (FIG. 29) is located inside the circumscribing rectangle of the connection pads 212R, 212G, 212B, and 212A (i.e., within the pixel area).

[0257] The connection pad 212R is made of a conductive material and has, for example, a square shape when viewed from the +Z direction side. It is located on the +X+Y direction side of the connection pad set 212T. The connection pad 212R is also disposed on the −Z direction side of the cathode pillar 240cR in the vertical wiring 222R, and the surface (upper surface) of the connection pad 212R on the +Z direction side (hereinafter also referred to as the connection pad surface 212RS) is exposed on the substrate surface 10S. The connection pad 212R is also electrically connected to the active element 214R inside the circuit board 210, and the connection pad surface 212RS is in contact with and electrically connected to the surface (lower surface) of the cathode pillar 240cR on the first thin film layer 220B on the −Z direction side (hereinafter also referred to as the cathode pillar lower surface 240cRS2).

[0258] The connection pad 212G has a configuration similar to the connection pad 212R and is located on the +XY direction side of the connection pad set 212T. The connection pad 212G is also disposed on the -Z direction side of the vertical wiring 222G (i.e., the cathode pillar 240cG1), and the surface (upper surface) of the connection pad 212G on the +Z direction side (hereinafter also referred to as the connection pad surface 212GS) is exposed on the substrate surface 10S. The connection pad 212G is also electrically connected to the active element 214G inside the circuit board 210, and the connection pad surface 212GS is in contact with and electrically connected to the surface (lower surface) on the -Z direction side of the cathode pillar 240cG1 of the first thin film layer 220B (hereinafter also referred to as the cathode pillar lower surface 240cG1S2).

[0259] The connection pad 212B has a configuration similar to that of the connection pad 212R and is located on the -X+Y direction side of the connection pad set 212T. The connection pad 212B is also disposed on the -Z direction side of the cathode electrode 234B in the vertical wiring 222B, and the surface (upper surface) of the connection pad 212B on the +Z direction side (hereinafter also referred to as the connection pad surface 212GS) is exposed on the substrate surface 10S. The connection pad 212B is also electrically connected to the active element 214B inside the circuit board 210, and the connection pad surface 212BS is in contact with and electrically connected to the surface (lower surface) of the cathode electrode 234B on the -Z direction side of the first thin-film layer 220B (hereinafter also referred to as the cathode electrode surface 234BS).

[0260] The connection pad 212A has a configuration similar to that of the connection pad 212R and is located on the −XY direction side of the connection pad set 212T. The connection pad 212A is also disposed on the −Z direction side of the anode pillar 242aB of the vertical wiring 222A, and the surface (upper surface) of the connection pad 212A on the +Z direction side (hereinafter also referred to as the connection pad surface 212AS) is exposed on the substrate surface 10S. The connection pad 212A is also electrically connected to the anode common wiring of the wiring layer 16 inside the circuit board 210, and the connection pad surface 212AS is in contact with and electrically connected to the surface (lower surface) on the −Z direction side of the anode pillar 242aB of the first thin film layer 220B (hereinafter also referred to as the anode pillar lower surface 242aBS2).

[0261] The active elements 214 (active elements 214R, 214G, and 214B) are arranged in a matrix (i.e., a grid) inside the circuit board 210. Hereinafter, the active elements 214R, 214G, and 214B will also be collectively referred to as active elements 214.

[0262] Active element 214R is composed of two MOS transistors and one capacitor, and is disposed on the −Z direction side of connection pad 212R and electrically connected to wiring inside wiring layer 16. Active elements 214G and 214B are configured similarly to active element 214R, and are disposed on the −Z direction side of connection pads 212G and 212B, respectively, and electrically connected to wiring inside wiring layer 16.

[0263] Although not shown in detail, the wiring inside the wiring layer 16 is arranged in a matrix (i.e., lattice) and is appropriately electrically connected to the active elements 214 (active elements 214R, 214G, and 214B) and connection pads 212 (212R, 212G, 212B, and 212A), as well as electrically connected to the driving driver 6.

[0264] The circuit board 210 has a board surface 10S that is formed as an extremely flat plane. That is, in the circuit board 210, the insulating layer surface 11S, which is the upper surface of the insulating layer 11, the connection pad surface 212RS, the connection pad surface 212GS, the connection pad surface 212BS, and the connection pad surface 212AS are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the insulating layer surface 11S, the connection pad surface 212RS, the connection pad surface 212GS, the connection pad surface 212BS, and the connection pad surface 212AS are all located on the same plane.

[0265] Specifically, in the circuit board 210, the surface roughness of the substrate surface 10S, i.e., the surface roughness (also called roughness or maximum surface step) Rpv of the insulating layer surface 11S, the connection pad surface 212RS, the connection pad surface 212GS, the connection pad surface 212BS and the connection pad surface 212AS are all 10 nm or less.

[0266] [3-4. Composition of thin film layers] 31 and 32, thin film layer group 218 includes three thin film layers 220, namely, first thin film layer 220B, second thin film layer 220R, and third thin film layer 220G, stacked from the -Z direction to the +Z direction. Thin film layer group 218 is physically bonded to circuit board 210 by intermolecular forces and is also electrically connected to circuit board 210.

[0267] The thin film layer group 218 has a plurality of pixels (pixel section 208) arranged in a matrix within the region of the LED display section 202. When viewed from the Z direction, the pixel section 208 is mainly composed of four vertical wires 222 (vertical wires 222A, 222R, 222G, and 222B) arranged at the four corners and corresponding to anodes and cathodes, and one light-emitting section 224 surrounded by the vertical wires 222 and arranged inside the pixel section 208. Hereinafter, the vertical wires 222A, 222R, 222G, and 222B will also be collectively referred to as vertical wires 222.

[0268] The vertical wiring 222A is made of a conductive material and is composed of an anode pad 244G, and anode pillars 242aR and 242aB. The vertical wiring 222R is made of a conductive material and is composed of cathode pads 241R and 240cR. The vertical wiring 222G is made of a conductive material and is composed of a cathode pad 241G, and cathode pillars 240cG2 and 240cG1. The vertical wiring 222B is made of a conductive material and is composed of a cathode electrode 234B.

[0269] The light-emitting section 224 is configured by the thin-film LEDs 30B, 30R, and 30G overlapping when viewed from the Z direction (light-emitting direction De) so as to be aligned from the -Z direction side toward the +Z direction side. In this embodiment, the thin-film LEDs 30R and 30G overlap in the Z direction so that their centers coincide with each other, the centers are located at the center of the pixel section 208 (i.e., the center of the pixel area), and their positions in the X and Y directions at their outer shapes coincide with each other. Furthermore, although the center of the thin-film LED 30B is shifted in the -X and +Y directions relative to the thin-film LEDs 30R and 30G, they partially overlap.

[0270] An anode common wiring is provided inside the circuit board 210. The anode common wiring is arranged linearly along the X and Y directions outside the area of ​​the LED display unit 202, and is also arranged linearly along the X direction between a light-emitting unit row consisting of a plurality of light-emitting units 224 lined up in the X direction and a light-emitting unit row adjacent to the light-emitting unit row in the Y direction. The anode common wiring terminates at a common anode connection terminal of the driver 6.

[0271] [3-4-1. Composition of the first thin film layer] As shown in Figures 31 and 32, and Figure 33 in which the same symbols are used for components corresponding to those in Figure 6, the first thin film layer 220B is composed of an underlying transparent insulating material 226B, a transparent insulating material 228B, a thin film LED 30B, an anode electrode 32B, a cathode electrode 234B, an extraction wiring 236aB, an interlayer insulating film 238aB, an anode pillar 242aB, and cathode pillars 240cR and 240cG1.

[0272] The underlying transparent insulating material 226B is made of, for example, SiO2, SiN, transparent polyimide, etc., and has sufficient insulating properties. This underlying transparent insulating material 226B extends from one end to the other end of the pixel unit 208 in the AA cross-sectional direction Da (FIG. 31), but underlying transparent insulating material openings 248cR and 248aB are formed at locations facing the connection pads 212R and 212A on the circuit board 210 in the Z direction, penetrating the underlying transparent insulating material 226B in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 226B (hereinafter also referred to as the underlying transparent insulating material upper surface 226BS1) to the surface (lower surface) on the -Z direction side (hereinafter also referred to as the underlying transparent insulating material lower surface 226BS2).

[0273] Furthermore, although the underlying transparent insulating material 226B extends from one end to the other end of the pixel section 208 in the BB cross-sectional direction Db (FIG. 32), underlying transparent insulating material openings 248cB1 and 248cG1 are formed in locations facing the connection pads 212B and 212G in the Z direction on the circuit board 210, respectively, penetrating the underlying transparent insulating material 226B in the Z direction (light-emitting direction De) from the underlying transparent insulating material upper surface 226BS1 to the underlying transparent insulating material lower surface 226BS2. A cathode electrode 234B is formed inside the underlying transparent insulating material opening 248cB.

[0274] The thin-film LED 30B is a thin-film inorganic light-emitting element embedded in a transparent insulating material 228B. The thin-film LED 30B is disposed at the center of the pixel unit 208 in the AA cross-sectional direction Da, but is offset from the center of the pixel unit 208 toward the -X and +Y directions. The thin-film LED 30B has a length within a predetermined range in the AA cross-sectional direction Da and the BB cross-sectional direction Db, a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 228B. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30B, is a flat surface extending along the X and Y directions. The thin-film LED 30B is an LED that emits blue light, for example, made of a GaN-based material. The anode electrode 32B is disposed on an anode formed at the center of the +Z direction side of the thin-film LED 30B. The cathode electrode 234B is disposed on a cathode formed on the -X and Y direction side of the -Z direction side of the thin-film LED 30B.

[0275] The lead-out wiring 236aB (FIG. 31) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32B on the +Z direction side and the anode pillar 242aB, respectively, to electrically connect them. The interlayer insulating film 238aB is made of an insulating material and is disposed between the lead-out wiring 236aB and the thin-film LED 30B, and is formed to be larger than the lead-out wiring 236aB when viewed along the Z direction. This interlayer insulating film 238aB protects unnecessary portions of the lead-out wiring 236aB and the thin-film LED 30B from short-circuiting.

[0276] The cathode electrode 234B is disposed opposite the connection pad 212B in the Z direction and constitutes the vertical wiring 222B. The cathode electrode 234B has a surface on the -Z direction side (hereinafter also referred to as the cathode electrode surface 234BS) exposed from the underlying transparent insulating material 226B. The cathode electrode 234B has an area equivalent to that of the cathode pillar 240cG1, for example.

[0277] The anode electrode 32B, cathode electrode 234B and lead wiring 236aB are made of a transparent conductive material such as ITO, and the interlayer insulating film 238aB is preferably transparent to the wavelength of light emitted by the thin-film LED 30B.

[0278] The cathode pillar 240cR (FIG. 31) is made of a conductive material such as gold, copper, or titanium, and is disposed opposite the connection pad 212R of the circuit board 210 in the Z direction, constituting a part of the vertical wiring 222R. Specifically, the cathode pillar 240cR is formed on (on the +Z direction side of) the contact metal 246cPL1B, which is a gold-based metal for process stabilization, and is integrated with the contact metal 246cPL1B. The cathode pillar 240cR is also composed of a titanium barrier layer, which serves as a copper diffusion prevention film, formed on the contact metal 246cPL1B, a copper seed metal formed on the barrier layer, and a copper plating portion that grows and fills the seed metal. The same is true for an anode pillar 242aB and a cathode pillar 240cG1 (described later). The anode pillar 242aB (FIG. 31) is formed on the contact metal 246aB (+Z direction side) and integrated with the contact metal 246aB. The cathode pillar 240cG1 (FIG. 32) is formed on the contact metal 246cPDG1 (+Z direction side) and integrated with the contact metal 246cPDG1. The +Z direction surface of the cathode pillar 240cR (hereinafter also referred to as a cathode pillar upper surface 240cRS1) is exposed from the transparent insulating material 228B.

[0279] The anode pillar 242aB (FIG. 31) is made of a conductive material, similar to the cathode pillar 240cR, and is disposed opposite the connection pad 212A of the circuit board 210 in the Z direction, constituting a part of the vertical wiring 222A. The anode pillar 242aB has its +Z direction surface (hereinafter also referred to as the anode pillar upper surface 242aBS1) exposed from the transparent insulating material 228B. The anode pillar 242aB has its -Z direction surface (the anode pillar lower surface 242aBS2) exposed from the underlying transparent insulating material 226B.

[0280] The cathode pillar 240cG1 (FIG. 32) is made of a conductive material like the cathode pillar 240cR, and is disposed opposite the connection pad 212G of the circuit board 210 in the Z direction, constituting part of the vertical wiring 222G. The cathode pillar 240cG1 has its +Z direction surface (hereinafter also referred to as the cathode pillar upper surface 240cG1S1) exposed from the transparent insulating material 228B. The cathode pillar 240cG1 has its -Z direction surface (the cathode pillar lower surface 240cG1S2) exposed from the underlying transparent insulating material 226B.

[0281] The transparent insulating material 228B is made of, for example, the same material as the underlying transparent insulating material 226B, and has sufficient insulating properties while being transparent to at least the wavelength of light emitted by the thin-film LEDs 30B. The transparent insulating material 228B is disposed so as to cover the underlying transparent insulating material 226B, the thin-film LEDs 30B, the anode electrode 32B, the lead-out wiring 236aB, and the interlayer insulating film 238aB from the +Z direction, excluding the anode pillar 242aB and the cathode pillars 240cR and 240cG1, and embeds the thin-film LEDs 30B, the anode electrode 32B, the lead-out wiring 236aB, and the interlayer insulating film 238aB between the underlying transparent insulating material 226B and the transparent insulating material 228B.

[0282] This transparent insulating material 228B (Figure 31) has a transparent insulating material opening 250aR formed on the +Z direction side of the underlying transparent insulating material opening 248cR, which penetrates the transparent insulating material 228B in the Z direction (light emitting direction De) from the surface (upper surface) on the +Z direction side of the transparent insulating material 228B (hereinafter also referred to as the transparent insulating material surface 228BS) to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 248cR).

[0283] Furthermore, the transparent insulating material 228B (Figure 32) has a transparent insulating material opening 250cG1 formed on the +Z direction side of the underlying transparent insulating material opening 248cG1, which penetrates the transparent insulating material 228B in the Z direction (light emitting direction De) from the transparent insulating material surface 228BS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 248cG1).

[0284] Furthermore, the transparent insulating material 228B (Figure 31) has a transparent insulating material opening 250aB formed on the +Z direction side of the underlying transparent insulating material opening 248aB, which penetrates the transparent insulating material 228B in the Z direction (light emitting direction De) from the transparent insulating material surface 228BS to the surface (bottom surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 248aB).

[0285] The base transparent insulating material opening 248cR and the transparent insulating material opening 250cR form a first thin film layer opening 252cR. The first thin film layer opening 252cR is formed from the upper surface of the first thin film layer 220B on the +Z direction side (hereinafter also referred to as the first thin film layer upper surface 220BS1) to the lower surface on the -Z direction side (the first thin film layer lower surface 220BS2), and has a cathode pillar 240cR formed therein. The base transparent insulating material opening 248cG1 and the transparent insulating material opening 250aG1 form a first thin film layer opening 252aR1. The first thin film layer opening 252aR1 is formed from the first thin film layer upper surface 220BS1 to the first thin film layer lower surface 220BS2, and has a cathode pillar 240cG1 formed therein. Furthermore, the base transparent insulating material opening 248aB and the transparent insulating material opening 250aB form a first thin film layer opening 252aB. The first thin film layer opening 252aB is formed from the first thin film layer upper surface 220BS1 to the first thin film layer lower surface 220BS2, and an anode pillar 242aB is formed inside the first thin film layer opening 252aB.

[0286] Furthermore, the first thin film layer 220B has a first thin film layer upper surface 220BS1 formed as an extremely flat plane. That is, in the first thin film layer 220B, the transparent insulating material surface 228BS, the anode pillar upper surface 242aBS1, and the cathode pillar upper surfaces 240cRS1 and 240cG1S1 are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the transparent insulating material surface 228BS, the anode pillar upper surface 242aBS1, and the cathode pillar upper surfaces 240cRS1 and 240cG1S1 are all located on the same plane.

[0287] Specifically, in the first thin film layer 220B, the surface roughness of the first thin film layer upper surface 220BS1, i.e., the surface roughness Rpv of the transparent insulating material surface 228BS, the anode pillar upper surface 242aBS1, and the cathode pillar upper surfaces 240cRS1 and 240cG1S1, are all 10 nm or less.

[0288] Furthermore, the first thin film layer 220B has a first thin film layer lower surface 220BS2 formed as an extremely flat plane. That is, in the first thin film layer 220B, the lower surface 226BS2 of the underlying transparent insulating material, the cathode electrode surface 234BS, the anode pillar lower surface 242aBS2, the cathode pillar lower surfaces 240cRS and 240cG1S2, and the surface (lower surface) on the -Z direction side of the lead-out wiring 236aB are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the lower surface 226BS2 of the underlying transparent insulating material, the cathode electrode surface 234BS, the anode pillar lower surface 242aBS2, the cathode pillar lower surfaces 240cRS2 and 240cG1S2, and the lower surface on the -Z direction side of the lead-out wiring 236aB are all located on the same plane.

[0289] Specifically, in the first thin film layer 220B, the surface roughness of the lower surface 220BS2 of the first thin film layer, i.e., the lower surface 226BS2 of the underlying transparent insulating material, the cathode electrode surface 234BS, the lower surface 242aBS2 of the anode pillar, the lower surfaces 240cRS2 and 240cG1S2 of the cathode pillar, and the surface roughness Rpv on the lower surface on the -Z direction side of the lead-out wiring 236aB are all 10 nm or less.

[0290] [3-4-2. Composition of the second thin film layer] As shown in Figures 31 and 32, and Figure 34, in which the same symbols are used for components corresponding to those in Figure 7, the second thin film layer 220R is composed of an underlying transparent insulating material 226R, a transparent insulating material 228R, a thin film LED 30R, an anode electrode 32R, a cathode electrode 234R, lead-out wiring 236aR and 236cR, interlayer insulating films 238aR and 238cR, an anode pillar 242aR, a cathode pad 241R, and a cathode pillar 240cG2.

[0291] The underlying transparent insulating material 226R is made of the same material as the underlying transparent insulating material 226B, and has sufficient insulating properties and is transparent to at least the wavelength of light emitted by the thin-film LED 30R. This underlying transparent insulating material 226R extends from one end to the other end of the pixel section 208 in the AA cross-sectional direction Da (FIG. 31). However, underlying transparent insulating material openings 248aR and 248R are formed at locations facing the first thin-film layer openings 252aB and 252cR in the Z direction in the first thin-film layer 220B, respectively, penetrating the underlying transparent insulating material 226R in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 226R (hereinafter also referred to as the underlying transparent insulating material upper surface 226RS1) to the surface (lower surface) on the −Z direction side (hereinafter also referred to as the underlying transparent insulating material lower surface 226RS2).

[0292] Furthermore, although the underlying transparent insulating material 226R extends from one end to the other end of the pixel section 208 in the BB cross-sectional direction Db (Figure 32), at a location opposite the first thin film layer opening 252cR1 in the Z direction in the first thin film layer 220B, an underlying transparent insulating material opening 248cR2 is formed that penetrates the underlying transparent insulating material 226R in the Z direction (light-emitting direction De) from the upper surface 226RS1 of the underlying transparent insulating material to the lower surface 226RS2 of the underlying transparent insulating material.

[0293] The thin-film LED 30R is a thin-film inorganic light-emitting element disposed in the center of the pixel unit 208 in the AA cross-sectional direction Da and the BB cross-sectional direction Db. The thin-film LED 30R has a predetermined length in the AA cross-sectional direction Da and the BB cross-sectional direction Db, a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 228R. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30R, is a flat surface extending along the XY direction. The thin-film LED 30R is a quaternary LED that emits red light and is formed from a III-V compound semiconductor material, such as a GaAs-based material. The anode electrode 32R is disposed on an anode formed in the center of the +Z direction side of the thin-film LED 30R. The cathode electrode 234R is disposed on a cathode formed on the +X+Y direction side of the +Z direction side of the thin-film LED 30R.

[0294] The lead-out wiring 236aR (FIG. 31) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32R on the +Z direction side and the anode pillar 242aR, respectively, to electrically connect them. The interlayer insulating film 238aR is made of an insulating material and is disposed between the lead-out wiring 236aR and the thin-film LED 30R, and is formed to be larger than the lead-out wiring 236aR when viewed along the Z direction. This interlayer insulating film 238aR protects unnecessary parts of the lead-out wiring 236aR and the thin-film LED 30R from short-circuiting.

[0295] The lead-out wiring 236cR (FIG. 31) is made of a conductive material like the lead-out wiring 236acR, and is in contact with the surface (upper surface) of the cathode electrode 234R on the +Z direction side and the cathode pad 241R, electrically connecting them. The interlayer insulating film 238cR is made of an insulating material like the interlayer insulating film 238cR, and is disposed between the lead-out wiring 236cR and the thin-film LED 30R, and is formed larger than the lead-out wiring 236cR when viewed along the Z direction. This interlayer insulating film 238cR protects unnecessary short circuits between the lead-out wiring 236cR and the thin-film LED 30R.

[0296] The above-mentioned anode electrode 32R, cathode electrode 234R, and lead-out wiring 236aR and 236cR are made of a transparent conductive material such as ITO, and it is desirable that the interlayer insulating films 238aR and 238cR are transparent to the wavelength of light emitted by the thin-film LEDs 30B and 30R.

[0297] The anode pillar 242aR (FIG. 31) is made of a conductive material such as gold, copper, or titanium. It is located opposite the anode pillar 242aB of the first thin film layer 220B in the Z direction and constitutes a part of the vertical wiring 222A. Specifically, the anode pillar 242aR is formed on (on the +Z direction side of) the contact metal 246aR, which is a gold-based metal for process stabilization, and is integrated with the contact metal 246aR. The anode pillar 242aR is also composed of a titanium barrier layer, which serves as a copper diffusion barrier film, formed on the contact metal 246aR, a copper seed metal formed on the barrier layer, and a copper plating portion grown and filled on the seed metal. The same applies to the cathode pillar 240cG2 (described later); the cathode pillar 240cG2 (FIG. 32) is formed on (on the +Z direction side of) the contact metal 246cPDG2 and is integrated with the contact metal 246cPDG2. The anode pillar 242aR has a surface on the +Z direction side (hereinafter also referred to as an anode pillar upper surface 242aRS1) exposed from the transparent insulating material 228R. Also, the anode pillar 242aR has a surface on the −Z direction side (hereinafter also referred to as an anode pillar lower surface 242aRS2) exposed from the underlying transparent insulating material 226R.

[0298] The cathode pad 241R (FIG. 31) is made of a conductive material similar to the anode pillar 242aR, and is disposed opposite the cathode pillar 240cR of the first thin film layer 220B in the Z direction, constituting a part of the vertical wiring 222R. The cathode pad 241R has its surface on the -Z direction side (hereinafter also referred to as the cathode pad surface 241RS) exposed from the underlying transparent insulating material 226R.

[0299] The cathode pillar 240cG2 (FIG. 32) is made of a conductive material similar to the anode pillar 242aR, and is disposed opposite the cathode pillar 240cG1 of the first thin film layer 220B in the Z direction, constituting part of the vertical wiring 222G. The cathode pillar 240cG2 has its +Z direction surface (hereinafter also referred to as the cathode pillar upper surface 240cG2S1) exposed from the transparent insulating material 228R. The cathode pillar 240cG2 has its -Z direction surface (hereinafter also referred to as the cathode pillar lower surface 240cG2S2) exposed from the underlying transparent insulating material 226R.

[0300] The transparent insulating material 228R is made of, for example, the same material as the underlying transparent insulating material 226R, and has sufficient insulating properties and is transparent to at least the wavelength of light emitted by the thin-film LEDs 30B and 30R. This transparent insulating material 228R is arranged to cover the underlying transparent insulating material 226R, thin-film LED 30R, anode electrode 32R, cathode electrode 234R, lead-out wiring 236aR and 236cR, interlayer insulating film 238aR and 238cR, and cathode pad 241R from the +Z direction side, excluding anode pillar 242aR and cathode pillar 240cG2, and these thin-film LED 30R, anode electrode 32R, cathode electrode 234R, lead-out wiring 236aR and 236cR, interlayer insulating film 238aR and 238cR, and cathode pad 241R are embedded inside between the underlying transparent insulating material 226R.

[0301] This transparent insulating material 228R (Figure 31) has a transparent insulating material opening 250aR formed on the +Z direction side of the underlying transparent insulating material opening 248aR, which penetrates the transparent insulating material 228R in the Z direction (light emitting direction De) from the surface (upper surface) on the +Z direction side of the transparent insulating material 228R (hereinafter also referred to as the transparent insulating material surface 228RS) to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 248aR).

[0302] Furthermore, the transparent insulating material 228R (Figure 32) has a transparent insulating material opening 250cR2 formed on the +Z direction side of the underlying transparent insulating material opening 248cR2, which penetrates the transparent insulating material 228R in the Z direction (light emitting direction De) from the transparent insulating material surface 228RS to the surface (lower surface) on the -Z direction side (i.e., the +Z direction side end of the underlying transparent insulating material opening 248cR2).

[0303] The base transparent insulating material opening 248aR and the transparent insulating material opening 250aR form a second thin film layer opening 252aR. The second thin film layer opening 252aR is formed from the upper surface of the second thin film layer 220R on the +Z direction side (hereinafter also referred to as the second thin film layer upper surface 220RS1) to the lower surface on the -Z direction side (hereinafter also referred to as the second thin film layer lower surface 220RS2), and an anode pillar 242aR is formed therein. The base transparent insulating material opening 248cR2 and the transparent insulating material opening 250cR2 form a second thin film layer opening 252cR2. The second thin film layer opening 252cR2 is formed from the second thin film layer upper surface 220RS1 to the second thin film layer lower surface 220RS2, and a cathode pillar 240cG2 is formed therein.

[0304] Furthermore, the second thin film layer 220R has a second thin film layer upper surface 220RS1 formed as an extremely flat plane. That is, in the second thin film layer 220R, the transparent insulating material surface 228RS, the anode pillar upper surface 242aRS1, and the cathode pillar upper surface 240cG2S1 are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the transparent insulating material surface 228RS, the anode pillar upper surface 242aRS1, and the cathode pillar upper surface 240cG2S1 are all located on the same plane.

[0305] Specifically, in the second thin film layer 220R, the surface roughness of the second thin film layer upper surface 220RS1, that is, the surface roughness Gpv of the transparent insulating material surface 228RS, the anode pillar upper surface 242aRS1, and the cathode pillar upper surface 240cG2S1, are all 10 nm or less.

[0306] Furthermore, the second thin film layer 220R has a second thin film layer lower surface 220RS2 formed in an extremely flat plane. That is, in the second thin film layer 220R, the underlying transparent insulating material lower surface 226RS2, the anode pillar lower surface 242aRS2, the cathode pillar lower surface 240cG2S2, the cathode pad surface 241RS, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wirings 236aR and 236cR are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the underlying transparent insulating material lower surface 226RS2, the anode pillar lower surface 242aRS2, the cathode pillar lower surface 240cG2S2, the cathode pad surface 241RS, and the lower surfaces of the lead-out wirings 236aR and 236cR are all located on the same plane.

[0307] Specifically, in the second thin film layer 220R, the surface roughness Gpv of the lower surface 220RS2 of the second thin film layer, i.e., the lower surface 226RS2 of the underlying transparent insulating material, the lower surface 242aRS2 of the anode pillar, the lower surface 240cG2S2 of the cathode pillar, the cathode pad surface 241RS, and the lower surfaces of the lead-out wiring 236aR and 236cR, are all 10 nm or less.

[0308] [3-4-3. Composition of the third thin film layer] As shown in Figures 31 and 32 and Figure 35, in which the same symbols are used for components corresponding to Figure 8, the third thin film layer 220G is composed of an underlying transparent insulating material 226G, a transparent insulating material 228G, a thin film LED 30G, an anode electrode 32G, a cathode electrode 234G, an anode pad 244G, a cathode pad 241G, lead wiring 236aG and 236cG, and interlayer insulating films 238aG and 238cG.

[0309] The underlying transparent insulating material 226G is made of the same material as the underlying transparent insulating material 226B, and has sufficient insulating properties and is transparent to at least the wavelengths of light emitted by the thin-film LEDs 30B, 30R, and 30G. This underlying transparent insulating material 226G extends from one end to the other end of the pixel section 208 in the AA cross-sectional direction Da (FIG. 31). However, at a location facing the second thin-film layer opening 252aR in the Z direction in the second thin-film layer 220R, an underlying transparent insulating material opening 248aG is formed that penetrates the underlying transparent insulating material 226G in the Z direction (light-emitting direction De) from the surface (upper surface) on the +Z direction side of the underlying transparent insulating material 226G (hereinafter also referred to as an underlying transparent insulating material upper surface 226GS1) to the surface (lower surface) on the −Z direction side (hereinafter also referred to as an underlying transparent insulating material lower surface 226GS2).

[0310] Furthermore, although the underlying transparent insulating material 226G extends from one end to the other end of the pixel section 208 in the BB cross-sectional direction Db (Figure 32), at a location opposite the second thin film layer opening 252cR2 in the second thin film layer 220R in the Z direction, an underlying transparent insulating material opening 248R is formed that penetrates the underlying transparent insulating material 226G in the Z direction (light-emitting direction De) from the upper surface 226GS1 of the underlying transparent insulating material to the lower surface 226GS2 of the underlying transparent insulating material.

[0311] The thin-film LED 30G is a thin-film inorganic light-emitting element disposed in the center of the pixel section 8 in the AA cross-sectional direction Da and the BB cross-sectional direction Db, has a predetermined length in the AA cross-sectional direction Da and the BB cross-sectional direction Db, has a thickness in the Z direction of 3 μm or less, and is embedded in a transparent insulating material 228G. The light-emitting surface, which is the upper surface on the +Z direction side of the thin-film LED 30G, is a flat surface extending along the XY direction. The thin-film LED 30G is an LED formed of, for example, a GaP-based material and emits green light. The anode electrode 32G is disposed on an anode formed in the center of the +Z direction side of the thin-film LED 30G. The cathode electrode 234G is disposed on a cathode formed on the +XY direction side of the +Z direction side of the thin-film LED 30G.

[0312] The lead-out wiring 236aG (FIG. 31) is made of a conductive material and is in contact with the surface (upper surface) of the anode electrode 32G on the +Z direction side and the anode pad 244G, respectively, to electrically connect them. The interlayer insulating film 238aG is made of an insulating material and is disposed between the lead-out wiring 236aG and the thin-film LED 30G, and is formed to be larger than the lead-out wiring 236aG when viewed along the Z direction. This interlayer insulating film 238aG protects unnecessary portions of the lead-out wiring 236aG and the thin-film LED 30G from short-circuiting.

[0313] The lead-out wiring 236cG (FIG. 32) is made of a conductive material similar to the lead-out wiring 236aG, and is in contact with the surface (upper surface) of the cathode electrode 234G on the +Z direction side and the cathode pad 241G, electrically connecting them. The interlayer insulating film 238cG is made of an insulating material, is disposed between the lead-out wiring 236cG and the thin-film LED 30G, and is larger than the lead-out wiring 236cG when viewed along the Z direction. This interlayer insulating film 238cG protects unnecessary portions of the lead-out wiring 236cG and the thin-film LED 30G from short-circuiting.

[0314] The above-mentioned anode electrode 32G, cathode electrode 234G and lead-out wiring 236aG are made of a transparent conductive material such as ITO, and it is desirable that the interlayer insulating film 238aR is transparent to the wavelength of light emitted by the thin-film LEDs 30B, 30R and 30G.

[0315] The anode pad 244G (FIG. 31) is made of a conductive material such as gold, copper, or titanium, and is disposed opposite the anode pillar 242aR of the second thin film layer 220R in the Z direction, constituting part of the vertical wiring 222A. The surface of this anode pad 244G on the -Z direction side (hereinafter also referred to as the anode pad surface 244GS) is exposed from the underlying transparent insulating material 226G.

[0316] The cathode pad 241G (FIG. 32) is made of a conductive material like the anode pad 244G, and is disposed opposite the cathode pillar 240cG2 of the second thin film layer 220R in the Z direction, constituting part of the vertical wiring 222G. The cathode pad 241G has a surface on the −Z direction side (hereinafter also referred to as a cathode pad surface 241GS) exposed from the underlying transparent insulating material 226G.

[0317] The transparent insulating material 228G is made of, for example, the same material as the underlying transparent insulating material 226G, and has sufficient insulating properties and is transparent to at least the wavelengths of light emitted by the thin-film LEDs 30B, 30R, and 30G. The transparent insulating material 228G is disposed so as to cover the underlying transparent insulating material 226G, thin-film LED 30G, anode electrode 32G, cathode electrode 234G, anode pad 244G, cathode pad 241G, lead-out wiring 236aG and 236cG, and interlayer insulating films 238aG and 238cG from the +Z direction side, and embeds the thin-film LED 30G, anode electrode 32G, cathode electrode 234G, anode pad 244G, cathode pad 241G, lead-out wiring 236aG and 236cG, and interlayer insulating films 238aG and 238cG between the transparent insulating material 228G and the underlying transparent insulating material 226G.

[0318] Furthermore, the third thin film layer 220G has a third thin film layer lower surface 220GS2 formed in an extremely flat plane. That is, in the third thin film layer 220G, the underlying transparent insulating material lower surface 226GS2, the anode pad surface 244GS, the cathode pad surface 241GS, and the surfaces (lower surfaces) on the -Z direction side of the lead-out wirings 236aG and 236cG are all extremely flat and parallel to each other, and the distance between them in the Z direction (i.e., the step) is also extremely small. That is, the underlying transparent insulating material lower surface 226GS2, the anode pad surface 244GS, the cathode pad surface 241GS, and the lower surfaces of the lead-out wirings 236aG and 236cG are all located on the same plane.

[0319] Specifically, in the third thin film layer 220G, the surface roughness Ppv of the lower surface 220GS2 of the third thin film layer, i.e., the lower surface 226GS2 of the underlying transparent insulating material, the anode pad surface 244GS, the cathode pad surface 241GS, and the lower surfaces of the lead-out wirings 236aG and 236cG, are all 10 nm or less. In the following, the lead-out wirings 236aB, 236aG, 236aR, 236acR, 236cB, 236cG, and 236cR will also be collectively referred to as lead-out wirings 236.

[0320] [3-5. Connection between thin film layers and circuit boards] [3-5-1. Physical connection relationship between circuit board and thin film layer] The substrate surface 10S of the circuit substrate 210 and the first thin film layer lower surface 220BS2 of the first thin film layer 220B are physically bonded by intermolecular forces. The first thin film layer upper surface 220BS1 of the first thin film layer 220B and the second thin film layer lower surface 220RS2 of the second thin film layer 220R are physically bonded by intermolecular forces. The second thin film layer upper surface 220RS1 of the second thin film layer 220R and the third thin film layer lower surface 220GS2 of the third thin film layer 220G are physically bonded by intermolecular forces.

[0321] In this way, in the LED display unit 202, the substrate surface 10S and the lower surface 220BS2 of the first thin film layer, the upper surface 220BS1 and the lower surface 220RS2 of the second thin film layer, and the upper surface 220RS1 and the lower surface 220GS2 of the second thin film layer are bonded by intermolecular forces rather than by metal bonding.

[0322] [3-5-2. Electrical connection between circuit board and thin film layer] The connection pad 212B (Figure 32) has a connection pad surface 212BS physically bonded to the cathode electrode surface 234BS of the cathode electrode 234B of the first thin-film layer 220B by intermolecular forces, and is electrically connected to the cathode electrode 234B of the thin-film LED 30B, like the conductive path Rbc.

[0323] The connection pad surface 212RS of the connection pad 212R (FIG. 31) is physically bonded to the cathode pillar lower surface 240cRS of the cathode pillar 240cR of the first thin-film layer 220B by intermolecular forces. The cathode pillar upper surface 240cRS1 of the cathode pillar 240cR is physically bonded to the cathode pad surface 241RS of the cathode pad 241R of the second thin-film layer 220R by intermolecular forces. The cathode pad 241R is in physical contact with the lead-out wiring 236cR. Therefore, the connection pad 212R is electrically connected to the cathode electrode 234R of the thin-film LED 30R via the cathode pillar 240cR, the cathode pad 241R, and the lead-out wiring 236cR, like the conductive path Rrc.

[0324] The connection pad surface 212GS of the connection pad 212G (FIG. 32) is physically bonded by intermolecular force to the cathode pillar lower surface 240cG1S2 of the cathode pillar 240cG1 of the first thin-film layer 220B. The cathode pillar upper surface 240cG1S1 of the cathode pillar 240cG1 is physically bonded by intermolecular force to the cathode pillar lower surface 240cG2S2 of the cathode pillar 240cG2 of the second thin-film layer 220R. The cathode pillar upper surface 240cG2S1 of the cathode pillar 240cG2 is physically bonded by intermolecular force to the cathode pad surface 241GS of the cathode pad 241G of the third thin-film layer 220G. The cathode pad 241G is in physical contact with the lead-out wiring 236cG. Therefore, the connection pad 212B is electrically connected to the cathode electrode 234G of the thin-film LED 30G via the cathode pillar 240cG1, the cathode pillar 240cG2, and the lead-out wiring 236cG, like the conductive path Rgc.

[0325] The connection pad surface 212AS of the connection pad 212A (FIG. 31) is physically bonded by intermolecular force to the anode pillar lower surface 242aBS2 of the anode pillar 242aB of the first thin-film layer 220B. The anode pillar upper surface 242aBS1 of the anode pillar 242aB is physically bonded by intermolecular force to the anode pillar lower surface 242aRS2 of the anode pillar 242aR of the second thin-film layer 220R. The anode pillar upper surface 242aRS1 of the anode pillar 242aR is physically bonded by intermolecular force to the anode pad surface 244GS of the anode pad 244G of the third thin-film layer 220G. The lead-out wiring 236aG is in physical contact with the anode pad 244G. Therefore, the anode electrode 32G is electrically connected to the anode common wiring of the wiring layer 16 via the lead wiring 236aG, the anode pad 244G, the anode pillar 242aR, the anode pillar 242aB, and the connection pad 212A, like the conductive path Ra.

[0326] The lead wiring 236aR is in physical contact with the contact metal 246aR. Therefore, the anode electrode 32R is electrically connected to the anode common wiring of the wiring layer 16 via the lead wiring 236aR, the contact metal 246aR, the anode pillar 242aR, the anode pillar 242aB, and the connection pad 212A, like the conductive path Ra.

[0327] Furthermore, the lead-out wiring 236aB is in physical contact with the contact metal 246aB. Therefore, the anode electrode 32B is electrically connected to the anode common wiring of the wiring layer 16 via the lead-out wiring 236aB, the contact metal 246aB, the anode pillar 242aB, and the connection pad 212A, like the conductive path Ra.

[0328] [3-6. LED display display manufacturing method] Next, an example of a manufacturing method for the LED display unit 202 in the LED display device 201 will be described with reference to Figures 36, 37, 38, and 39, in which the same reference numerals are used to designate parts corresponding to those in Figures 9, 10, 11, and 12, respectively. Incidentally, Figures 36, 37, 38, and 39 are all schematic cross-sectional views showing a state in which the +Z direction faces upward. For convenience of explanation, the +Z direction will also be referred to as the upward direction, and the -Z direction will also be referred to as the downward direction.

[0329] [3-6-1. Manufacturing method of the first thin film layer] First, a manufacturing method of the first thin film layer 220B will be described with reference to Fig. 36. First, as shown in Fig. 36(A), the manufacturing apparatus 60 performs a step of growing a thin film LED layer 266B on the upper side, i.e., the +Z direction side, of a predetermined LED growth substrate 262B. In this embodiment, a sapphire substrate is used as an example of the LED growth substrate 262B.

[0330] Next, as shown in Fig. 36(B), the manufacturing apparatus 60 separates the thin-film LED layer 266B from the LED growth substrate 262B by a known laser lift-off method. It is desirable to flatten the separated surface of the thin-film LED layer 266B by polishing or the like.

[0331] 36(C), the manufacturing equipment 60 sequentially deposits a sacrificial layer 270B and a base transparent insulating material 226B on the formation substrate 268B of the first thin film layer 220B, and bonds the thin film LED layer 266B to the base transparent insulating material 226B by intermolecular forces. At this time, the top surfaces (side surfaces in the +Z direction) of the sacrificial layer 270B and the base transparent insulating material 226B need to be flat to Rpv=10 [nm] or less, so the manufacturing equipment 60 may perform a smoothing process such as polishing.

[0332] Next, as shown in Figure 36(D), the manufacturing equipment 60 forms the thin-film LED 30B by etching the thin-film LED layer 266B through an etching process, and also patterns the underlying transparent insulating material openings 248aB, 248cR, 248cB (Figure 32) and 248aG1 (Figure 32) in the underlying transparent insulating material 226B.

[0333] Next, as shown in Figure 36(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32B, a cathode electrode 234B (Figure 32), an interlayer insulating film 238aB, an extraction wiring 236aB, and contact metals 246aB, 246cPL1B, and 246cPDG1 (Figure 32) on the thin-film LED 30B and the underlying transparent insulating material 226B.

[0334] Next, as shown in FIG. 36(F), the manufacturing equipment 60 fills in the transparent insulating material 228B and patterns the transparent insulating material openings 250aB, 250cR, and 250cCG1 (FIG. 32) in the transparent insulating material 228B, and then uses a plating method to form anode pillars 242aB and cathode pillars 240cR and 240cG1 (FIG. 32) on the contact metals 246aB, 246cPL1B, and 246cPDG1 (FIG. 32) exposed from the transparent insulating material openings 250aB, 250cR, and 250cG1 (FIG. 32).

[0335] Next, as shown in FIG. 36(G), the manufacturing equipment 60 performs a planarization process using chemical mechanical polishing (CMP) to planarize the upper surfaces of the transparent insulating material 228B, the anode pillar 242aB, and the cathode pillars 240cR and 240cG1 (FIG. 32), thereby forming an anode pillar upper surface 242aBS1 on the upper surface of the anode pillar 242aB and cathode pillar upper surfaces 240cRS1 and 240cG1S1 (FIG. 32) on the upper surfaces of the cathode pillars 240cR and 240cG1 (FIG. 32), respectively, so that they are exposed from the upper surface of the transparent insulating material 228B.

[0336] [3-6-2. Manufacturing method of second thin film layer] Next, a manufacturing method of the second thin-film layer 220R will be described with reference to Fig. 37. First, as shown in Fig. 37(A), the manufacturing apparatus 60 forms a lattice-matched sacrificial layer 264R on the upper side of a predetermined LED growth substrate 262R, i.e., on the +Z direction side, and then grows a thin-film LED layer 266R on the upper side. In this embodiment, as an example, GaAs is used as the LED growth substrate 262R, and a material such as GaAs containing Al is used as the sacrificial layer 264R.

[0337] 37(B), the manufacturing apparatus 60 separates the thin-film LED layer 266R from the LED growth substrate 262R by etching and removing the sacrificial layer 264R by an etching process. It is desirable to flatten the separated surface of the thin-film LED layer 266R by polishing or the like.

[0338] 37(C), the manufacturing equipment 60 sequentially deposits a sacrificial layer 270R and an underlying transparent insulating material 226R on a formation substrate 268R for the second thin film layer 220R, and bonds the thin film LED layer 266R to the underlying transparent insulating material 226R by intermolecular forces. At this time, since the upper surfaces (side surfaces in the +Z direction) of the sacrificial layer 270R and the underlying transparent insulating material 226R need to be flat to Rpv=10 [nm] or less, the manufacturing equipment 60 may perform a smoothing process such as polishing.

[0339] Next, as shown in Figure 37(D), the manufacturing equipment 60 forms thin-film LEDs 30R by etching the thin-film LED layer 266R using an etching process, and also patterns underlying transparent insulating material openings 248aR, 248R, and 248cR2 (Figure 32) in the underlying transparent insulating material 226R.

[0340] Next, as shown in Figure 37(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32R, a cathode electrode 234R, interlayer insulating films 238aR and 238cR, lead wiring 236aR and 236cR, and contact metals 246aR, 246cPDR, and 246cPDG2 (Figure 32) on the thin-film LED 30R and the underlying transparent insulating material 226R.

[0341] Next, as shown in Fig. 37(F), the manufacturing equipment 60 fills the transparent insulating material 228R, patterns the transparent insulating material 228R to form transparent insulating material openings 250aR and 250cR2 (Fig. 32), and then forms an anode pillar 242aR and a cathode pillar 240cG2 (Fig. 32) on the contact metals 246aR and 246cPDG2 (Fig. 32) exposed from the transparent insulating material openings 250aR and 250cR2 (Fig. 32) by plating. The contact metal 246cPDR becomes the cathode pad 241R.

[0342] Next, as shown in Figure 37(G), the manufacturing equipment 60 performs a planarization process using chemical mechanical polishing (CMP) to planarize the upper surfaces of the transparent insulating material 228R, the anode pillar 242aR, and the cathode pillar 240cG2 (Figure 32), thereby forming an anode pillar upper surface 242aRS1 and a cathode pillar upper surface 240cG2S1 (Figure 32) on the upper surfaces of the anode pillar 242aR and the cathode pillar 240cG2 (Figure 32), respectively, so that they are exposed from the upper surface of the transparent insulating material 228R.

[0343] [3-6-3. Manufacturing method of the third thin film layer] Next, a manufacturing method of the third thin film layer 220G will be described with reference to Fig. 38. First, as shown in Fig. 38(A), the manufacturing apparatus 60 performs a step of growing a thin film LED layer 266G on the upper side, i.e., the +Z direction side, of a predetermined LED growth substrate 262G. In this embodiment, a sapphire substrate is used as an example of the LED growth substrate 262G.

[0344] Next, as shown in Fig. 38(B), the manufacturing apparatus 60 separates the thin-film LED layer 266G from the LED growth substrate 262G by a known laser lift-off method. It is desirable to flatten the separated surface of the thin-film LED layer 266G by polishing or the like.

[0345] 38(C), the manufacturing equipment 60 sequentially deposits a sacrificial layer 270G and an underlying transparent insulating material 226G on a formation substrate 268G for the third thin film layer 220G, and bonds the thin film LED layer 266G to the underlying transparent insulating material 226G by intermolecular forces. At this time, the upper surfaces (side surfaces in the +Z direction) of the sacrificial layer 270G and the underlying transparent insulating material 226G need to be flat to Rpv=10 [nm] or less, so the manufacturing equipment 60 may perform a smoothing process such as polishing.

[0346] Next, as shown in Figure 38(D), the manufacturing equipment 60 forms thin-film LEDs 30G by etching the thin-film LED layer 266G through an etching process, and also patterns the underlying transparent insulating material openings 248aG and 248R (Figure 32) in the underlying transparent insulating material 226G.

[0347] Next, as shown in Fig. 38(E), the manufacturing equipment 60 performs a patterning process using techniques such as lithography or sputtering to form an anode electrode 32G, a cathode electrode 234G (Fig. 32), interlayer insulating films 238aG and 238cG (Fig. 32), lead wirings 236aG and 236cG (Fig. 32), and contact metals 246aG and 246cPDG (Fig. 32) on the thin-film LED 30G and the underlying transparent insulating material 226G. The contact metal 246aG becomes the anode pad 244G, and the contact metal 246cPDG (Fig. 32) becomes the cathode pad 241G.

[0348] Next, the manufacturing equipment 60 fills in the transparent insulating material 228G as shown in Fig. 38(F). The manufacturing equipment 60 may perform a planarization process using chemical mechanical polishing (CMP) to flatten the upper surface of the transparent insulating material 128R.

[0349] [3-6-4.Layered joining process] Next, the process of laminating and bonding the first thin film layer 220B, the second thin film layer 220R, and the third thin film layer 220G manufactured by the above-mentioned manufacturing method onto the circuit board 210 will be described with reference to Figure 39, in which the same symbols are used for components corresponding to those in Figure 12.

[0350] First, as shown in FIG. 39(A), the manufacturing equipment 60 separates the first thin film layer 220B from the formation substrate 268B by etching and removing the sacrificial layer 270B (FIG. 36). As a result, the anode pillar lower surface 242aBS2, the cathode pillar lower surface 240cRS2, the cathode electrode surface 234BS (FIG. 32), and the cathode pillar lower surface 240cG1S2 (FIG. 32) are exposed from the lower surface 226BS2 of the underlying transparent insulating material. The anode pillar lower surface 242aBS2, the cathode pillar lower surface 240cRS2, the cathode electrode surface 234BS (FIG. 32), and the cathode pillar lower surface 240cG1S2 (FIG. 32) are formed flat and flush with the upper surface of the sacrificial layer 270B (FIG. 36). Next, the manufacturing equipment 60 bonds the separated first thin film layer 220B to the upper surface of the circuit board 210 by intermolecular forces using a known bonding method.

[0351] Next, as shown in FIG. 39(B), the manufacturing equipment 60 separates the second thin film layer 220R from the formation substrate 268R by etching and removing the sacrificial layer 270R (FIG. 37). As a result, the anode pillar lower surface 242aRS2, the cathode pad surface 241RS, and the cathode pillar lower surface 240cG1S2 (FIG. 32) are exposed from the lower surface 226RS2 of the underlying transparent insulating material. The anode pillar lower surface 242aRS2, the cathode pad surface 241RS, and the cathode pillar lower surface 240cG2S2 (FIG. 32) are formed flat and flush with the upper surface of the sacrificial layer 270R (FIG. 37). Next, the manufacturing equipment 60 bonds the separated second thin film layer 220R by a known bonding method using intermolecular forces to the top surface of the first thin film layer 220B that has been bonded to the circuit board 210 in FIG. 39(A).

[0352] Next, as shown in FIG. 39(C), the manufacturing equipment 60 separates the third thin film layer 220G from the formation substrate 268G by etching and removing the sacrificial layer 270G (FIG. 38). This exposes the anode pad surface 244GS and the cathode pad surface 241GS (FIG. 32) from the lower surface 226GS2 of the underlying transparent insulating material. The anode pad surface 244GS and the cathode pad surface 241GS (FIG. 32) are formed flat and flush with the upper surface of the sacrificial layer 270G (FIG. 38). Next, the manufacturing equipment 60 bonds the separated third thin film layer 220G to the upper surface of the second thin film layer 220R, which was bonded to the first thin film layer 220B in FIG. 39(B), by intermolecular forces using a known bonding method.

[0353] [3-7. LED display illumination] 40, when the LED display unit 202 emits light, the blue light LB emitted toward the second thin-film layer 220R is absorbed by the thin-film LED 30R because the thin-film LED 30R is made of a GaAs substrate and absorbs wavelengths shorter than 660 nm (red), which corresponds to Eg = 1.9 eV. On the other hand, the portions of the second thin-film layer 220R other than the thin-film LED 30R are transparent to the wavelength of the blue light LB, so the blue light LB passes through the portions of the second thin-film layer 220R other than the thin-film LED 30R. Furthermore, the thin-film LED 30G is made of a GaP substrate and absorbs wavelengths shorter than 564 nm (green), which corresponds to Eg = 2.2 eV. Therefore, the blue light LB emitted toward the third thin-film layer 220G is absorbed by the thin-film LED 30G, but the red light LR passes through without being absorbed by the thin-film LED 30G. On the other hand, the portions of the third thin film layer 220G other than the thin film LEDs 30G are transparent to the wavelength of the blue light LB, so the blue light LB passes through the portions of the third thin film layer 220G other than the thin film LEDs 30G.

[0354] Furthermore, the portions of the third thin film layer 220G other than the thin film LEDs 30G are transparent to the wavelength of the red light LR, so the red light LR passes through the portions of the third thin film layer 220G other than the thin film LEDs 30G.

[0355] In the pixel unit 208 according to this embodiment, the thin-film LED 30B is arranged with its center displaced in the -Y+Y direction (i.e., offset) with respect to the centers of the thin-film LEDs 30R and 30G. Therefore, the second thin-film layer 220R absorbs a portion of the blue light LB that is directed toward the thin-film LED 30R, but transmits the green light LG that is directed toward portions other than the thin-film LED 30R, directing it in the +Z direction.

[0356] [3-8. Overlapping of thin film layers] Here, when the pixel unit 208 is viewed from the +Z direction along the light-emitting direction De, as shown in FIG. 41(A) in which the same reference numerals are used to denote components corresponding to those in FIG. 14(A), the hatched region where the thin-film LED 30B overlaps with both the thin-film LED 30G and the thin-film LED 30R located further toward the thin-film LED 30B in the +Z direction is referred to as the light-absorbing region ARa. In the third embodiment, the thin-film LED 30G and the thin-film LED 30R are not offset from each other, so the light-absorbing region ARa is the region where the thin-film LED 30B overlaps with the thin-film LED 30G. Furthermore, when the pixel unit 208 is viewed from the +Z direction along the light-emitting direction De, as shown in FIG. 41(B) in which the same reference numerals are used to denote components corresponding to those in FIG. 14(B), the hatched region where the thin-film LED 30R and the thin-film LED 30G located further toward the thin-film LED 30B in the +Z direction overlap is referred to as the light-transmitting region ARt. In the pixel section 208 according to the present embodiment, the thin-film LEDs 30B, 30G, and 30R are arranged so that the light absorbing region ARa (FIG. 41(A)) is smaller than the light transmitting region ARt (FIG. 41(B)).

[0357] [3-9.Effects] In the LED display device 201 according to the third embodiment, the thin-film LED 30B of the first thin-film layer 220B, the thin-film LED 30R of the second thin-film layer 220R, and the thin-film LED 30G of the third thin-film layer 220G are stacked in this order, so that the thin-film LED 30R is located in the central layer. Also, in the LED display device 201, the center of the thin-film LED 30B is offset from the thin-film LEDs 30R and 30G.

[0358] Therefore, compared to when the thin-film LEDs 30B, 30R, and 30G are arranged with their centers aligned with each other, the LED display device 201 can move at least a portion of the thin-film LEDs 30R and 30G away from the path of the blue light LB heading in the +Z direction, thereby increasing the amount of blue light LB that is emitted outside the LED display device 201 without being absorbed by the thin-film LEDs 30R and 30G.

[0359] Furthermore, although the LED display device 101 does not place the second thin film layer 220R on the top layer, but places the third thin film layer 220G above the second thin film layer 220R, the red light LR is not absorbed by the third thin film layer 220G, and therefore the red light LR can be emitted outside the LED display device 201 without being significantly attenuated.

[0360] In addition, the LED display device 201 according to the third embodiment can achieve the same effects as the LED display device 1 according to the first embodiment.

[0361] According to the above configuration, the LED display device 201 comprises a circuit board 210, a first thin-film layer 220B provided on the circuit board 210 and including a thin-film LED 30B as a first light-emitting element having the bandgap of the thin-film LED 30B as a first bandgap, a third thin-film layer 220G including a thin-film LED 30G as a second light-emitting element having the bandgap of the thin-film LED 30G as a second bandgap different from the bandgap of the thin-film LED 30B, and a second thin-film layer 220R laminated between the first thin-film layer 220B and the third thin-film layer 220G and including a thin-film LED 30R having the bandgap of the thin-film LED 30R as a third bandgap that is smaller than the bandgap of the thin-film LED 30B and the bandgap of the thin-film LED 30G, The thin-film LED 30B is arranged so that, when viewed from the stacking direction, the light absorbing area ARa, which is the area where the thin-film LED 30B overlaps with the thin-film LED 30R and the thin-film LED 30G, is smaller than the light transmitting area ARt, which is the area where the thin-film LED 30G overlaps with the thin-film LED 30R.

[0362] 4. Other Embodiments In the first embodiment described above, the thin-film LEDs 30G, 30B, and 30R are sequentially stacked from the -Z direction side to the +Z direction side. The present invention is not limited to this. The positions of the thin-film LEDs 30G and 30B may be interchanged, and the thin-film LEDs 30B, 30G, and 30R may be sequentially stacked from the -Z direction side to the +Z direction side. In this case, since the thin-film LED 30G absorbs the blue light LB from the thin-film LED 30B, the thin-film LED 30B on the bottom layer side may be offset with respect to the thin-film LEDs 30R and 30G.

[0363] In the first embodiment, the thin-film LEDs 30R are arranged on the top layer side. However, the present invention is not limited to this. The thin-film LEDs 30R may be arranged on an intermediate layer between the top layer and the bottom layer. The same applies to the second embodiment.

[0364] Furthermore, in the above-described first embodiment, the thin-film LEDs 30G and 30B are described as being center-aligned and not offset from each other. However, the present invention is not limited to this. For example, the thin-film LEDs 30G and 30B may be slightly offset from each other by a distance shorter than the offset amount of the thin-film LED 30R relative to the thin-film LEDs 30G and 30B. The same applies to the relationship between the thin-film LEDs 30R and 30G in the third embodiment.

[0365] Furthermore, in the above-described first embodiment, the thin-film LED 30R is offset relative to the thin-film LEDs 30G and 30B so as to partially overlap when viewed from the Z direction. However, the present invention is not limited to this. The thin-film LED 30R may be offset relative to the thin-film LEDs 30G and 30B so as not to partially overlap when viewed from the Z direction. In this case, the size of the area where the thin-film LED 30R overlaps with the thin-film LEDs 30G and 30B when viewed from the Z direction is zero. In this way, the small overlapping area between the thin-film LEDs 30 when viewed from the Z direction also includes the overlapping area being zero (i.e., the size of the light absorption area ARa (FIG. 14(A)) is zero). Similarly, in the second embodiment, the thin-film LED 30R may be offset relative to the thin-film LEDs 30B and 30G so as not to partially overlap when viewed from the Z direction. In the third embodiment, the thin-film LED 30B may be offset relative to the thin-film LEDs 30R and 30G so as not to partially overlap when viewed from the Z direction.

[0366] In the second embodiment described above, the thin-film LEDs 30B, 30G, and 30R are stacked in order from the -Z direction side to the +Z direction side. However, the present invention is not limited to this. The positions of the thin-film LEDs 30B and 30G may be interchanged, and the thin-film LEDs 30G, 30B, and 30R may be stacked in order from the -Z direction side to the +Z direction side.

[0367] Furthermore, in the above-described third embodiment, the thin-film LEDs 30B, 30R, and 30G are sequentially stacked from the -Z direction side to the +Z direction side. However, the present invention is not limited to this. The positions of the thin-film LEDs 30B and 30G may be interchanged, and the thin-film LEDs 30G, 30R, and 30B may be sequentially stacked from the -Z direction side to the +Z direction side.

[0368] Furthermore, in the above-described third embodiment, the thin-film LEDs 30R are offset from the thin-film LEDs 30B but are not offset from the thin-film LEDs 30G. However, the present invention is not limited to this, and the thin-film LEDs 30R may be offset from the thin-film LEDs 30G and the thin-film LEDs 30B.

[0369] Furthermore, in the third embodiment described above, a member that reflects the red light LR may be provided on the second thin-film layer 220R on the -Z direction side of the thin-film LED 30R.

[0370] Furthermore, in the first embodiment described above, the thin-film LEDs 30G, 30B, and 30R are formed to have the same size in a plan view. However, the present invention is not limited to this, and the thin-film LEDs 30 may have different sizes. What is important is that they overlap at least partially when viewed from the Z direction. The same applies to the second and third embodiments.

[0371] Furthermore, in the first embodiment described above, the thin-film LED 30R is offset in the −XY direction relative to the thin-film LEDs 30G and 30B. However, the present invention is not limited to this. The thin-film LED 30R may be offset in any direction within the pixel relative to the thin-film LEDs 30G and 30B. However, by offsetting the thin-film LED 30R in a direction that overlaps with the cathode pillars 40cB and 40cG and directly connecting the cathode electrode 34R to the lower surface of the thin-film LED 30R as in the first embodiment, the thin-film LED 30R can be configured as a vertical LED (vertical LED) in which the anode and cathode are arranged on the upper and lower surfaces of the thin-film LED 30R. The thin-film LED 30R, which is a vertical LED, does not require an area for providing lead-out wiring such as the lead-out wiring 36cG and 36cB, as is the case with the thin-film LEDs 30G and 30B, which are horizontal LEDs (horizontal LEDs) in which the anode and cathode are arranged on one surface of the thin-film LED 30R. Furthermore, the thin-film LED 30R does not require a non-light-emitting region for providing the cathode electrodes 34G and 34B as in the thin-film LEDs 30G and 30B, and therefore the light-emitting efficiency per area can be improved. Therefore, the size of the thin-film LED 30R may be reduced by the amount corresponding to the improvement in the light-emitting efficiency per area of ​​the thin-film LED 30R, thereby efficiently extracting light from the thin-film LEDs 30G and 30B. The same applies to the thin-film LED 30R in the third thin-film layer 120R according to the second embodiment and the thin-film LED 30B in the first thin-film layer 220B according to the third embodiment.

[0372] Furthermore, in the first embodiment described above, the cathode common wiring is described as being wired inside the circuit board 10. However, the present invention is not limited to this, and the cathode common wiring may be wired on the upper surface of the third thin film layer 20R or on the substrate surface 10S. This is the same in the second embodiment. This is also the same in the anode common wiring according to the third embodiment.

[0373] Furthermore, in the first embodiment described above, the film size of each thin film layer 20 is described as being equal to the display size of the LED display unit 2. However, the present invention is not limited to this. For example, the third thin film layer 20R may be divided into two parts, each of which is half the display size, while maintaining the same number and pitch of pixels for the entire display. For example, if divided into two parts, the number of pixels included in the third thin film layer 20R will be half the number when the third thin film layer 20R is the size of the entire display. In this case, each thin film layer 20 can be manufactured with any number of pixels, from the number of pixels for the entire display down to one pixel. Furthermore, in this case, the film size of the third thin film layer 20R is smaller, making it easier to align the film of the third thin film layer 20 when it is superimposed on and bonded to the film of another thin film layer 20. This also applies to the second and third embodiments.

[0374] Furthermore, in the first embodiment described above, the active element 14 is configured with two MOS transistors and one capacitor. However, the present invention is not limited to this. The active element 14 may include circuits having various other functions, such as a circuit for gradation control, a compensation circuit, a redundancy circuit, etc., in addition to the basic structure of two MOS transistors and one capacitor. The same applies to the second and third embodiments.

[0375] Furthermore, in the first embodiment described above, the driver 6 is mounted on the surface of the circuit board 10. However, the present invention is not limited to this, and the driver 6 may be mounted on the surface of the connection cable 4, or the driver 6 may be formed as a CMOS circuit inside the circuit board 10 by a semiconductor process. The same applies to the second and third embodiments.

[0376] Furthermore, in the first embodiment described above, the circuit board 10 is configured as a CMOS circuit board. However, the present invention is not limited to this, and the circuit board 10 may be configured as a thin film transistor (TFT) circuit board. The same applies to the second and third embodiments.

[0377] Furthermore, in the first embodiment described above, the LED display unit 2 is described as having three thin film layers 20: the first thin film layer 20G, the second thin film layer 20B, and the third thin film layer 20R. However, the present invention is not limited to this. A fourth or fifth thin film layer may be bonded to the third thin film layer 20R to expand the light output and color gamut. Alternatively, a two-color display may be formed by combining only two of the three thin film layers 20: the first thin film layer 20G, the second thin film layer 20B, and the third thin film layer 20R. That is, the LED display unit 2 may have any number of thin film layers 20, such as two, four, or more, other than three. This also applies to the second and third embodiments.

[0378] Furthermore, in the first embodiment described above, the present invention is applied to a direct-view LED display device 1. However, the present invention is not limited to this, and may be applied to a display used as a projector or a light source. The same applies to the second and third embodiments.

[0379] Furthermore, the present invention is not limited to the above-described embodiments and other embodiments. That is, the scope of application of the present invention also extends to embodiments in which the above-described embodiments are combined in part or in whole with any of the above-described other embodiments. The scope of application of the present invention also extends to embodiments in which part of the configuration described in any of the above-described embodiments and other embodiments is extracted and used as part of the configuration of any of the above-described embodiments and other embodiments, or in which part of the extracted configuration is added to any of the above-described embodiments.

[0380] Furthermore, in the above-described first embodiment, the LED display device 1 as a light-emitting device is described as being configured by the circuit board 10 as a substrate, the first thin-film layer 20G as a first layer, the second thin-film layer 20B as a second layer, and the third thin-film layer 20R as a third layer. However, the present invention is not limited to this, and the light-emitting device may be configured by a substrate having various other configurations, and the first layer, second layer, and third layer.

[0381] Furthermore, in the second embodiment described above, the LED display device 101 as a light-emitting device is configured by the circuit board 110 as a substrate, the first thin-film layer 120B as a first layer, the second thin-film layer 120G as a second layer, and the third thin-film layer 120R as a third layer. However, the present invention is not limited to this, and the light-emitting device may be configured by a substrate having various other configurations, and the first layer, second layer, and third layer.

[0382] Furthermore, in the above-described third embodiment, the LED display device 201 as a light-emitting device is described as being configured by the circuit board 210 as a substrate, the first thin-film layer 220B as a first layer, the third thin-film layer 220G as a second layer, and the second thin-film layer 220R as a third layer. However, the present invention is not limited to this, and the light-emitting device may be configured by a substrate having various other configurations, and the first layer, second layer, and third layer. [Industrial Applicability]

[0383] The present invention can be used, for example, in an LED display having an arrangement of multiple LEDs. [Explanation of symbols]

[0384] 1, 101, 201...LED display device, 2, 102, 202...LED display unit, 3...heat dissipation member, 4...connection cable, 5...connection terminal unit, 6...driver, 8, 108, 208...pixel unit, 10, 110, 210...circuit board, 10M...substrate unit, 10S...substrate surface, 11...insulating layer, 11S...insulating layer surface, 12B, 12C, 12G, 12R, 112B, 112C, 112G, 112R, 212A, 212B, 212G, 212R...connection pad, 12BS, 12CS, 12GS, 12RS, 112BS, 112CS, 1 12GS, 112RS, 212AS, 212BS, 212GS, 212RS...connection pad surfaces, 12T, 112T, 212T...connection pad sets, 14B, 14G, 14R, 114B, 114G, 114R, 214B, 214G, 214R...active elements, 16...wiring layer, 18, 118, 218...thin film layer group, 20G, 120B, 220B...first thin film layer, 20B, 120G, 220R...second thin film layer, 20R, 120R, 220G...third thin film layer, 20GS1, 120BS1, 220BS1...top surface of first thin film layer, 20GS2, 120BS2 , 220BS2...lower surface of first thin film layer, 20BS1, 120GS1, 220RS1...upper surface of second thin film layer, 20BS2, 120GS2, 220RS2...lower surface of second thin film layer, 20RS2, 120RS2, 220GS2...lower surface of third thin film layer, 22B, 22C, 22G, 22R, 122B, 122C, 122G, 122R, 222A, 222B, 222G, 222R...vertical wiring, 24, 124, 224...light-emitting portion, 26B, 26G, 26R, 126B, 126G, 126R, 226B, 226G, 226R...underlying transparent insulating material, 26BS1, 26GS 1.26RS1 Transparent insulating material bottom surface, 28B, 28G, 28R, 128B, 128G, 128R, 228B, 228G, 228R...Transparent insulating material, 28BS, 28GS, 128BS, 128GS, 228BS, 228RS...Transparent insulating material surface, 30B, 30G, 30R...Thin film LED, 32B,32G, 32R, 132R...Anode electrode, 34B, 34G, 34R, 134B, 134G, 134R, 234B, 234G, 234R...Cathode electrode, 34RS, 134RS, 234BS...Cathode electrode surface, 36aB, 36aG, 36aR, 36cB, 36cG, 136aB, 136aG, 136aR, 136cB, 136cG, 236aB, 236aG, 236aR, 236acR, 236cB, 236cG, 236cR...Exit wiring, 38aB, 38aG, 38aR, 38cB, 38cG, 138aB, 138aG, 138aR, 1 38cB, 138cG, 238aB, 238aG, 238aR, 238cG, 238cR...interlayer insulating film, 40cB, 40cG, 140cB, 140cG, 240cG1, 240cG2, 240cR...cathode pillar, 40cBS1, 40cGS1, 140cBS1, 140cGS1, 240cG1S1, 240cG2S1, 240cRS1...cathode pillar upper surface, 40cBS2, 40cGS2, 140cBS2, 140cGS2, 240cG1S2, 240cG2S2, 240cRS2...cathode pillar lower surface, 241G, 241R...cathode Cathode pad, 241GS, 241RS... Cathode pad surface, 42aB, 42aR1, 42aR2, 142aG, 142aR1, 142aR2, 242aB, 242aR... Anode pillar, 42aBS1, 42aR1S1, 42aR2S1, 142aGS1, 142aR1S1, 142aR2S1, 242aBS1, 242aRS1... Anode pillar upper surface, 42aBS2, 42aR1S2, 42aR2S2, 142aGS2, 142aR1S2, 142aR2S2, 242aBS2, 242aRS2... Anode pillar lower surface, 44R, 44G, 144B, 144G, 144R, 244G...Anode pad, 44BS, 44GS, 44RS, 144BS, 144GS, 144RS, 244GS...Anode pad surface, 46aPDB, 46aPDG, 46aPDR, 46aPL1G, 46aPL2G, 46aPLB, 46cB, 46cG, 146aPDB, 146aPDG, 146aPDR, 146aPL1B, 146aPL2B, 146aPLG, 146cB, 146cG, 246aB, 246aG, 246aR, 246cPDG1, 246cPDG2, 246cPDG, 246cPDR,246cPL1B……Contact metal, 48B, 48G, 48R, 48aB, 48aR1, 48aR2, 48cB, 48cG, 48cR, 148B, 148G, 148R, 148aG, 148aR1, 148aR2, 148cB, 148cG, 148cR, 248R, 248aB, 248aG, 248aR, 248cB, 248cG1, 248cR, 248cR2……Underground transparent insulating material opening, 50 aB, 50aR1, 50aR2, 50cB, 50cG, 150aG, 150aR1, 150aR2, 150cB, 150cG, 250aB, 250aG1, 250aR, 250cR, 250cR2... Openings in transparent insulating materials, 52aB, 52aR1, 52cG, 152aG, 152aR1, 152cB, 252aB, 252aR1... Openings in the first thin film layer, 52aR2, 52cB, 152aR2, 152c... G, 252aR, 252cR2... Second thin film layer opening, 60... Manufacturing apparatus, 62B, 62G, 62R, 162B, 162G, 162R, 262B, 262G, 262R... LED growth substrate, 64R, 70B, 70G, 70R, 164R, 170B, 170G, 170R, 264R, 270B, 270G, 270R... Sacrifice layer, 66B, 66G, 66R, 166B, 166G, 166R, 266B... 266G, 266R… Thin-film LED layer; 68B, 68G, 68R, 168B, 168G, 168R, 268B, 268G, 268R… Forming substrate; ARa… Light absorption area; ARt… Light transmission area; Da… AA cross-sectional direction; Db… BB cross-sectional direction; De… Light emission direction; LB… Cyan light; LG… Green light; LR… Red light; Rc, Rra, Rga, Rba, Ra, Rrc, Rgc, Rbc… Conductive circuit.

Claims

1. a substrate having a substrate surface; a first layer provided on the substrate surface and including a first light-emitting element having a first band gap and emitting either blue or green light; a second layer including a second light-emitting element having a second band gap different from the first band gap and emitting the other of blue or green light; a third layer including a third light-emitting element having a third band gap smaller than the first band gap and the second band gap and emitting red light; and the second layer and the third layer are formed on the first layer in a predetermined order; The third light-emitting element is When viewed from a direction perpendicular to the substrate surface, the third light emitting element is arranged so that an area where the third light emitting element overlaps with the first light emitting element and the second light emitting element is smaller than an area where the first light emitting element and the second light emitting element overlap, and the third light emitting element has an area where the third light emitting element does not overlap with the first light emitting element and the second light emitting element. Light-emitting device.

2. the second layer is laminated on the first layer; The third layer is laminated on the second layer. The light emitting device according to claim 1 .

3. the third layer is laminated on the first layer; The second layer is laminated onto the third layer. The light emitting device according to claim 1 .

4. Further comprising an electrode electrically connected to the third light-emitting element, The third light-emitting element is The first light emitting element and the second light emitting element are disposed so that at least a part of the region that does not overlap with each other is in contact with the electrode. The light emitting device according to claim 1 .

5. A substrate; a first layer provided on the substrate and including a first light-emitting element having a first band gap and emitting either blue or green light; a second layer including a second light-emitting element having a second band gap different from the first band gap and emitting the other of blue or green light; a third layer stacked between the first layer and the second layer, the third layer including a third light-emitting element having a third band gap smaller than the first band gap and the second band gap and emitting red light; and The first light-emitting element is When viewed from the stacking direction, the first light emitting element is arranged such that an area where the first light emitting element overlaps with the second light emitting element and the third light emitting element is smaller than an area where the second light emitting element overlaps with the third light emitting element; The second light-emitting element and the third light-emitting element are When viewed from the stacking direction, the first light-emitting element is disposed so as to have an area that does not overlap with the first light-emitting element. Light-emitting device.

6. Further comprising an electrode electrically connected to the first light-emitting element, The first light-emitting element is The second light emitting element and the third light emitting element are disposed so that at least a part of the region that does not overlap with the second light emitting element and the third light emitting element is in contact with the electrode. The light emitting device according to claim 5 .

7. The second bandgap is larger than the first bandgap.

7. The light emitting device according to claim 1.

8. a substrate having a substrate surface; a first layer provided on the substrate surface and including a first light-emitting element that emits either blue or green light; a second layer including a second light-emitting element that emits the other of blue and green light; a third layer including a third light-emitting element that emits light of a red wavelength; and the second layer and the third layer are formed on the first layer in a predetermined order; The third light-emitting element is When viewed from a direction perpendicular to the substrate surface, the third light emitting element is arranged so that an area where the third light emitting element overlaps with the first light emitting element and the second light emitting element is smaller than an area where the first light emitting element and the second light emitting element overlap, and the third light emitting element has an area where the third light emitting element does not overlap with the first light emitting element and the second light emitting element. Light-emitting device.

9. Further comprising an electrode electrically connected to the third light-emitting element, The third light-emitting element is The first light emitting element and the second light emitting element are disposed so that at least a part of the region that does not overlap with each other is in contact with the electrode. The light emitting device according to claim 8 .

10. A substrate; a first layer provided on the substrate and including a first light-emitting element that emits either blue or green light; a second layer including a second light-emitting element that emits the other of blue and green light; a third layer stacked between the first layer and the second layer and including a third light-emitting element that emits red light; and The first light-emitting element is When viewed from the stacking direction, the first light emitting element is arranged such that an area where the first light emitting element overlaps with the second light emitting element and the third light emitting element is smaller than an area where the second light emitting element overlaps with the third light emitting element; The second light-emitting element and the third light-emitting element are When viewed from the stacking direction, the first light-emitting element is disposed so as to have an area that does not overlap with the first light-emitting element. Light-emitting device.

11. Further comprising an electrode electrically connected to the first light-emitting element; The first light-emitting element is The second light emitting element and the third light emitting element are disposed so that at least a part of the region that does not overlap with the second light emitting element and the third light emitting element is in contact with the electrode. The light emitting device according to claim 10.

12. an electrode provided in the third layer closer to the substrate than the third light-emitting element, electrically connecting the third light-emitting element and the substrate and reflecting light emitted by the third light-emitting element; 12. The light emitting device according to claim 1, further comprising:

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