Light-emitting device

Abstract

To improve luminescence characteristics. [Solution] The LED display device 1 includes a lower first layer having a first light-emitting element having a first light-emitting layer with a first band gap, an upper second layer including a second light-emitting element having a second light-emitting layer with a second band gap larger than the first band gap, which is arranged to overlap at least a part of the first light-emitting element when viewed from a light emission direction E perpendicular to the light-emitting surface of the first light-emitting element, and is positioned between the first and second layers in the light emission direction E, and has a third band gap that is larger than the first band gap and less than or equal to the second band gap.

Description

Technical Field

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

Background Art

[0002] In recent years, light-emitting devices such as display devices that display an image by selectively driving and emitting a plurality of light-emitting elements mounted in a matrix on a circuit board have been widely spread. In this light-emitting device, although a method of arranging light-emitting elements of a plurality of colors constituting each pixel side by side on a plane parallel to the image plane is common, there has been a problem that it is difficult to increase the density. Therefore, a light-emitting device having a stacked structure in which light-emitting elements of a plurality of colors constituting each pixel are arranged so as to be stacked in a direction perpendicular to the image plane has been proposed.

[0003] In this light-emitting device, due to the characteristics of the material constituting the light-emitting element, the ratio of light of a color with a relatively short wavelength (for example, blue) being absorbed by an element with a color having a relatively long wavelength (for example, red) increases, so it is known that the amount of light (luminance) emitted from the light-emitting surface decreases. Therefore, in the above-described light-emitting device, an element that emits light with a relatively short wavelength such as blue is arranged on the light-emitting direction side to ensure the amount of these lights (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a light-emitting device in which light-emitting elements having different wavelengths are stacked so as to overlap, there has been a case where a light-emitting element having a long wavelength is excited by a light-emitting element having a short wavelength and emits light unintentionally.

[0006] This invention was made with the above points in mind, and aims to propose a light-emitting device that can improve light emission characteristics. [Means for solving the problem]

[0007] To solve these problems, the present invention provides a light-emitting device comprising: a first layer having a first light-emitting element having a first light-emitting layer having a first band gap; a second layer including a second light-emitting element having a second light-emitting layer having a second band gap larger than the first band gap, which is arranged to overlap at least a part of the first light-emitting element when viewed from the light-emitting direction perpendicular to the light-emitting surface of the first light-emitting element; and a first light-absorbing layer having a third band gap larger than the first band gap and less than or equal to the second band gap, which is arranged between the first light-emitting layer and the second light-emitting layer in the light-emitting direction.

[0008] The present invention allows light emitted from the second light-emitting layer in the second layer and diffused toward the first layer to be absorbed by the first light-absorbing layer, preventing it from reaching the first light-emitting layer in the first layer. Therefore, the present invention can prevent the first light-emitting layer from being excited by light from the second light-emitting layer and generating excitation light. [Effects of the Invention]

[0009] According to the present invention, light emitted from the second light-emitting layer in the second layer and diffused toward the first layer can be absorbed by the first light-absorbing layer, preventing it from reaching the first light-emitting layer in the first layer. Therefore, the present invention can prevent the first light-emitting layer from being excited by light from the second light-emitting layer and generating excitation light. Thus, the present invention can realize a light-emitting device that can improve light emission characteristics. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the configuration of an LED display device. [Figure 2]The diagram shows the configuration of the LED display unit, with (A) being a top view and (B) being a side view. [Figure 3] This is a plan view showing the configuration of the third thin film layer according to the first embodiment. [Figure 4] This is a plan view showing the configuration of the second thin film layer according to the first embodiment. [Figure 5] This is a plan view showing the configuration of the first thin film layer and circuit board according to the first embodiment. [Figure 6] The configuration of the LED display unit according to the first embodiment is shown in the cross-sectional view taken along the arrow AA in Figures 3, 4, and 5. [Figure 7] This is a cross-sectional view taken along the line AA in Figure 4, showing the manufacturing process of the second thin film layer according to the first embodiment. [Figure 8] This is a cross-sectional view taken along the line AA in Figure 5, showing the manufacturing process of the first thin film layer according to the first embodiment. [Figure 9] This is a plan view showing the configuration of the second thin film layer according to the second embodiment. [Figure 10] The configuration of the LED display unit according to the second embodiment is shown in the cross-sectional view taken along the arrow AA in Figures 3, 5, and 9. [Figure 11] This is a plan view showing the configuration of the third thin film layer according to the third embodiment. [Figure 12] This is a plan view showing the configuration of the second thin film layer according to the third embodiment. [Figure 13] The configuration of the LED display unit according to the third embodiment is shown in the cross-sectional view taken along the arrow AA in Figures 5, 11, and 12. [Modes for carrying out the invention]

[0011] The embodiments for carrying out the invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

[0012] [1. First Embodiment] [1-1. Configuration of LED display device] As shown in FIGS. 1 and 2, the LED (Light Emitting Diode) display device 1 has an LED display section 2, a heat radiating member 3, a connection cable 4, a connection terminal section 5, and the like. The LED display device 1 as a light emitting device is also called a micro LED display, and is a display device in which a set of LED elements that emit red, green, and blue light respectively corresponds to one pixel.

[0013] As shown in FIGS. 2(A) and (B), in the LED display section 2, a thin film layer group 18 is provided on the surface on the +Z direction side of the flat circuit board 10 (hereinafter also referred to as the board surface 10S).

[0014] The circuit board 10 as a control board has a wiring layer, drive elements, drive circuits, etc. (all not shown) connected to the wiring layer, and is a board that is electrically connected to the LEDs of each pixel and selectively drives the LEDs. Hereinafter, in FIG. 1, the direction from left to right on the paper surface is defined as the +X direction, the direction from the lower left to the upper right on the paper surface is defined as the +Y direction, and the direction from the bottom to the top on the paper surface is defined as the +Z direction. Also hereinafter, the surface on the +Z direction side of each part is also called the upper surface, and the surface on the -Z direction side is also called the lower surface.

[0015] The thin film layer group 18 has a configuration in which three thin film layers 20, namely, a first thin film layer 20R, a second thin film layer 20G, and a third thin film layer 20B, are sequentially laminated from the -Z direction to the +Z direction. Hereinafter, the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B are also collectively referred to as the thin film layer 20. In addition, in the thin film layer group 18, within the display area 2A of the LED display section 2, a plurality of pixel portions 8 constituting each pixel are formed so as to be arranged in a lattice (matrix) shape along the X direction and the Y direction. In other words, in the LED display section 2, a plurality of pixel portions 8 are arranged in an array along the X direction and the Y direction.

[0016] Each pixel portion 8 occupies a square-shaped area when viewed from the Z-direction and is arranged in a grid pattern along the X and Y directions. Specifically, the length of each pixel portion 8 in both the X and Y directions is 1 [mm] or more, and the thickness in the Z direction (i.e., the thickness of the thin film layer group 18) is 100 [μm] or less. Hereinafter, the surface of the pixel portion 8 closest to the Z direction, i.e., the surface from which light is emitted, will also be referred to as the light-emitting surface 8S.

[0017] As shown in Figure 2(B), each pixel 8 has a light-emitting element 21R that emits red light formed in the first thin film layer 20R, a light-emitting element 21G that emits green light formed in the second thin film layer 20G, and a light-emitting element 21B that emits blue light formed in the third thin film layer 20B. Each pixel 8 also has wiring and other components that supply power to each light-emitting element 21 (light-emitting elements 21R, 21G, and 21B). Each light-emitting element 21 is configured as an inorganic light-emitting diode and emits light in accordance with the power supplied via the wiring and other components. As a result, each pixel 8 can emit light of various colors and intensities from its respective light-emitting surface 8S in the +Z direction (details will be described later).

[0018] Thus, the LED display unit 2 is a display device in which a plurality of pixel units 8 are arranged in a matrix on a circuit board 10 which is an active matrix circuit board, and by emitting a desired color in each pixel unit 8, an image can be displayed in the display area 2A.

[0019] The heat dissipation member 3 (Figure 1) is made of a metal material with relatively high thermal conductivity, such as aluminum, and is constructed in a flat rectangular parallelepiped shape overall. This heat dissipation member 3 is installed in contact with the LED display unit 2 on the -Z direction side of the LED display unit 2, that is, on the side opposite to the surface on which images are displayed, thereby dissipating heat from the circuit board 10. The connecting cable 4 is electrically connected to a predetermined control device (not shown) via the connecting terminal 5, and transmits the image signal supplied from the control device to the circuit board 10. As a result, the LED display device 1 displays an image based on the image signal supplied from the control device (not shown) or the like in the display area 2A of the LED display unit 2.

[0020] In the following, the designation of components related to the first thin film layer 20R will be suffixed with "R", the designation of components related to the second thin film layer 20G will be suffixed with "G", and the designation of components related to the third thin film layer 20B will be suffixed with "B". In the following, the direction in which light emitted from the display area 2A of the LED display unit 2 mainly propagates, and the direction perpendicular to the upper surface of the first thin film layer 20R (i.e., the +Z direction), will also be called the light emission direction E. Furthermore, in the following, the direction in which the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B are stacked (i.e., the Z direction), will also be called the stacking direction.

[0021] [1-2. Overall configuration of the LED display unit] Next, the detailed configuration of the LED display unit 2 (Figure 2) will be explained with reference to Figures 3, 4, 5, and 6. Figure 3 shows a schematic plan view of the portion corresponding to one pixel 8 in the third thin film layer 20B, as seen from the +Z direction. Figure 4 shows a schematic plan view of the portion corresponding to one pixel 8 in the second thin film layer 20G, as seen from the +Z direction. Figure 5 shows a schematic plan view of the portion corresponding to one pixel 8 in the first thin film layer 20R and the circuit board 10, as seen from the +Z direction. Note that Figure 6 is a cross-sectional view, but hatching has not been applied for the sake of drawing convenience.

[0022] As shown in Figure 6, the circuit board 10 is a CMOS (Complementary Metal Oxide Semiconductor) backplane circuit board manufactured by a silicon process. This circuit board 10 has a laminated structure made of multiple types of materials and includes a base material 11, cathode substrate pads 12 (cathode substrate pads 12B, 12G, and 12R), anode substrate pad 13, a common wiring layer 19, as well as insulating layers, circuit elements, and wiring layers (not shown).

[0023] The base material 11 is mainly composed of silicon or the like, and is appropriately provided with the aforementioned insulating layer, element and wiring layer, etc. (not shown). The cathode substrate pads 12 (cathode substrate pads 12B, 12G, and 12R) and anode substrate pad 13 are located on the +Z side of the circuit board 10, and the surface on the +Z side of each is part of the substrate surface 10S. Each pixel 8 contains one cathode substrate pad 12B, 12G, and 12R and one anode substrate pad 13.

[0024] The cathode substrate pads 12B, 12G, and 12R, and the anode substrate pad 13 are made of conductive materials such as Au (gold), Cu (copper), Al (aluminum), and ITO (Indium Tin Oxide), and are square in shape when viewed from the Z direction. These cathode substrate pads 12B, 12G, and 12R, and the anode substrate pad 13 are electrically connected to circuit elements (not shown) inside the circuit board 10 by predetermined wiring materials.

[0025] The cathode substrate pad 12B is located on the -X side (Figure 5) within the pixel section 8. The cathode substrate pad 12B is also located on the -Z side of the vertical wiring 23B (Figure 6), and its upper surface is in contact with the lower surface of the vertical wiring 23B, thereby electrically connecting them.

[0026] The cathode substrate pad 12G is located on the +X side (Figure 5) within the pixel section 8. The cathode substrate pad 12G is also located on the -Z side of the vertical wiring 23G (Figure 6), and its upper surface is in contact with the lower surface of the vertical wiring 23G, thereby electrically connecting them.

[0027] The cathode substrate pad 12R is located on the +Y direction side (Figure 5) within the pixel section 8. The cathode substrate pad 12R is also located on the -Z direction side of the vertical wiring 23R (Figure 6), and its upper surface is in contact with the lower surface of the vertical wiring 23R, thereby electrically connecting them.

[0028] The anode substrate pad 13 is located on the -Y direction side (Figure 5) within the pixel section 8. The anode substrate pad 13 is also located on the -Z direction side of the vertical wiring 23A (Figure 6), and its upper surface is in contact with the lower surface of the vertical wiring 23A, thereby electrically connecting them.

[0029] As mentioned above, the substrate surface 10S of the circuit board 10 is formed in an extremely flat planar shape. That is, in the circuit board 10, the upper surfaces of the base material portion 11, cathode substrate pads 12B, 12G, and 12R, and anode substrate pad 13 are all extremely flat and are parallel to each other, and furthermore, the distance (i.e., step difference) between them in the Z direction is also extremely small. In other words, the upper surfaces of the base material portion 11, cathode substrate pads 12B, 12G, and 12R, and anode substrate pad 13 are all located on the same plane. Specifically, in the circuit board 10, the surface roughness of the substrate surface 10S, that is, the surface roughness (also called the maximum surface step difference) Rz on the upper surfaces of the base material portion 11, cathode substrate pads 12B, 12G, and 12R, and anode substrate pad 13, is all 10 [nm] or less.

[0030] The common wiring layer 19 (Figure 6) is made of a conductive material, is formed as a thin film in the Z direction, and is located on the upper surface of the circuit board 10. This common wiring layer 19 consists of an anode substrate pad 13 provided at a position in contact with the vertical wiring 23A, and an inter-pixel connection portion (not shown). The inter-pixel connection portion is connected to the anode substrate pad 13 in each pixel portion 8, and is also interconnected with the inter-pixel connection portions of adjacent pixel portions 8 in the X direction. Furthermore, the inter-pixel connection portion is electrically connected to adjacent inter-pixel connection portions in the Y direction outside the display area 2A (Figure 1), and is also connected to the common anode connection terminal of the circuit board 10.

[0031] [1-3. Composition of the Thin Film Layers] Next, we will explain the detailed configuration of the circuit board 10 and the thin film layer group 18 in the LED display unit 2, focusing on the pixel unit 8, which is the area of ​​one pixel.

[0032] [1-3-1. Overall structure of the thin film layer group] As shown in Figure 2(B), the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B constituting the thin film layer group 18 each contain light-emitting elements 21R, 21G, and 21B that emit red (R), green (G), and blue (B) light, respectively, as well as various wiring materials. In other words, in the thin film layer group 18, the dominant wavelength of the red light emitted from the first thin film layer 20R is longer than the dominant wavelength of the green light emitted from the second thin film layer 20G and the dominant wavelength of the blue light emitted from the third thin film layer 20B. Also, in the thin film layer group 18, the dominant wavelength of the green light emitted from the second thin film layer 20G is longer than the dominant wavelength of the blue light emitted from the third thin film layer 20B.

[0033] Each thin film layer 20 is constructed as a single film, with lengths in the X and Y directions slightly greater than the display area 2A of the LED display unit 2 (Figure 1), while its length (thickness) in the Z direction is extremely short (thin). Both the surface on the +Z direction and the surface on the -Z direction of each thin film layer 20 are formed to be extremely flat.

[0034] Specifically, the surface roughness Rz of these surfaces is 10 nm or less. Therefore, in the LED display unit 2, the circuit board 10 and the first thin film layer 20R, the first thin film layer 20R and the second thin film layer 20G, and the second thin film layer 20G and the third thin film layer 20B are all physically joined by intermolecular forces, and the conductive parts on each surface are also electrically connected to each other.

[0035] As described above, within the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B, light-emitting elements 21R, 21G, and 21B, formed at positions corresponding to each pixel 8, are arranged in a grid pattern along the X and Y directions. In other words, in the LED display unit 2, each thin film layer 20 constituting the thin film layer group 18 is not configured as an independent thin film layer 20 for each pixel, but rather as a single thin film layer 20 in which the pixels of the entire display area 2A are arranged in a grid pattern. Hereafter, the light-emitting elements 21R, 21G, and 21B will be collectively referred to as the light-emitting unit 22.

[0036] Furthermore, the light-emitting section 22 is arranged such that, when viewed from the Z direction, the centers of the light-emitting elements 21R, 21G, and 21B are approximately the same, and these centers are located approximately in the center of the pixel section 8, that is, approximately in the center of the pixel section 8 in the X and Y directions. Each of the light-emitting elements 21R, 21G, and 21B is configured as a thin-film LED and has an anode and a cathode, respectively (details will be described later).

[0037] Furthermore, as shown in Figures 3 to 6, each pixel 8 is provided with vertical wiring 23B, 23G, 23R, and 23A (hereinafter collectively referred to as vertical wiring 23) at four locations around the light-emitting section 22. Each vertical wiring 23 is formed in the shape of a rectangular prism with a central axis along the Z direction, and the entire structure is conductive due to the appropriate stacking of multiple conductive layers in the Z direction.

[0038] The vertical wiring 23B (Figure 6) is located on the -X side of the light-emitting section 22 and extends across the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B, electrically connecting the cathode substrate pad 12B of the circuit board 10 to the cathode of the light-emitting element 21B. The vertical wiring 23G is located on the +X side of the light-emitting section 22 and extends across the first thin film layer 20R and the second thin film layer 20G, electrically connecting the cathode substrate pad 12G of the circuit board 10 to the cathode of the light-emitting element 21G.

[0039] The vertical wiring 23R is located on the +Y direction side of the light-emitting section 22 and is provided within the first thin film layer 20R, electrically connecting the cathode substrate pad 12R of the circuit board 10 to the cathode of the light-emitting element 21R. In other words, the vertical wirings 23B, 23G, and 23R individually electrically connect the circuit board 10 to the third thin film layer 20B, the second thin film layer 20G, and the first thin film layer 20R, respectively.

[0040] The vertical wiring 23A is located on the -Y direction side of the light-emitting section 22 and is provided across the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B, electrically connecting the anode substrate pad 13 of the circuit board 10 with the anodes of the light-emitting elements 21R, 21G, and 21G. In other words, the vertical wiring 23A functions as a common terminal (so-called common) that is electrically connected to each other, penetrating through the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B.

[0041] In this manner, the pixel section 8 supplies power to the light-emitting elements 21R, 21G, and 21B respectively via the circuit board 10, the common wiring layer 19, and the vertical wiring 23A, and the four vertical wirings 23 allow current to flow from the light-emitting elements 21R, 21G, and 21B to the circuit board 10.

[0042] [1-3-2. Composition of the first thin film layer] As shown in Figures 2, 5, and 6, the first thin film layer 20R has portions that constitute the light-emitting element 21R and each vertical wiring 23, as well as an underlay insulating layer 25R and an interlayer insulating layer 26R. The first thin film layer 20R also has portions that are significantly related to the light-emitting part 22, such as the cathode lead wiring 43R and an insulating layer 37R, in addition to the light-emitting element 21R being composed of a cathode layer 31R, a light-emitting layer 32R and an anode layer 33R.

[0043] Furthermore, the first thin film layer 20R mainly comprises cathode electrode pads 42RR, 42GR, and 42BR, anode electrode pad 42AR, anode pillar 45R, and cathode pillars 46GR and 46BR, which are portions relating to each vertical wiring 23.

[0044] The underlying insulating layer 25R, also called the base layer, is composed of a transparent insulating material made of organic insulating materials such as polyimide resin, epoxy resin, or acrylic resin, or inorganic insulating materials such as SiO2 (silicon dioxide) or SiN (silicon nitride), and provides sufficient insulation. Although this underlying insulating layer 25B is formed as a uniformly flat thin film overall, four openings 38BR, 38GR, 38RR, and 38AR, which are rectangular prism-shaped holes penetrating in the Z direction, are formed at four locations on the -X, +X, +Y, and -Y sides of the light-emitting element 21R, that is, in the parts corresponding to the vertical wiring 23B, 23G, 23R, and 23A mentioned above.

[0045] The light-emitting element 21R is constructed by sequentially stacking the cathode layer 31R, light-emitting layer 32R, and anode layer 33R on the +Z side of the cathode lead wiring 43R on the +Z side of the underlying insulating layer 25R, from the -Z side to the +Z side, and is configured as a thin film with a thickness of 3 [μm] or less in the Z direction, thus forming a thin-film inorganic LED overall. The cathode layer 31R, light-emitting layer 32R, and anode layer 33R are all configured as single or multiple layers, with flat top and bottom surfaces, forming thin films.

[0046] The cathode layer 31R, the light-emitting layer 32R, and the anode layer 33R (Figure 5) are formed in a circular shape when viewed from the Z direction and are located approximately in the center of the pixel portion 8 in the X and Y directions.

[0047] The cathode lead-out wiring 43R, when viewed from the Z direction, has a shape that combines a circular portion identical in shape to the cathode layer 31R, light-emitting layer 32R, and anode layer 33R, with a roughly rectangular portion protruding from the circular portion in the +Y direction, with the center of the circular portion located approximately at the center of the pixel portion 8 in the X and Y directions. The cathode lead-out wiring 43R is constructed as a single-layer or multi-layer laminated structure of a transparent conductive film made of a material such as ITO, or a metal such as Au, Al, Cu, Pt (platinum), or Ti (titanium), or an alloy thereof. This cathode lead-out wiring 43R is formed to connect the light-emitting element 21R and the vertical wiring 23R along the Y direction. Specifically, the cathode lead-out wiring 43R is electrically connected to the cathode layer 31R on the light-emitting element 21R side. The cathode lead-out wiring 43R is also electrically connected to the cathode electrode pad 42RR on the vertical wiring 23R side.

[0048] The insulating layer 37R is composed of, for example, an organic insulating film or an inorganic insulating film, and has electrical insulating properties. This insulating layer 37R electrically insulates the anode pillar 45R from the cathode lead wiring 43R, the cathode layer 31R, and the light-emitting layer 32R, preventing short circuits.

[0049] The interlayer insulating layer 26R is formed to fill the +Z direction portion of the light-emitting element 21R and the cathode lead-out wiring 43R. This interlayer insulating layer 26R is formed as an organic or inorganic film that transmits visible light and also has electrical insulating properties. The upper surface of the interlayer insulating layer 26R is formed to be extremely flat, with a surface roughness Rz of 10 [nm] or less.

[0050] The cathode electrode pads 42RR, 42GR, and 42BR are part of the vertical wiring 23R, 23G, and 23B, respectively, and are constructed as a single-layer or multi-layer laminated structure of metals such as Au, Al, Cu, Pt, or Ti, or alloys thereof, and are electrically conductive. The cathode electrode pads 42RR, 42GR, and 42BR are formed to cover the openings 38RR, 38GR, and 38BR formed in the underlying insulating layer 25B, respectively, and their lower surfaces form the same plane as the lower surface of the underlying insulating layer 25R. The lower surfaces of these cathode electrode pads 42RR, 42GR, and 42BR are in contact with the cathode substrate pads 12R, 12G, and 12B of the circuit board 10, respectively, and are electrically connected. The upper surfaces of the cathode electrode pads 42GR and 42BR are in contact with the cathode pillars 46GR and 46BR, respectively, and are electrically connected. The cathode electrode pad 42RR is electrically connected to the cathode lead wire 43R by making contact with its upper surface.

[0051] The anode electrode pad 42AR is part of the vertical wiring 23A and is constructed as a single-layer or multi-layer laminated structure of a metal such as Au, Al, Cu, Pt, or Ti, or an alloy thereof, and is conductive. The anode electrode pad 42AR is formed to cover the opening 38AR formed in the underlying insulating layer 25R, and its lower surface forms the same plane as the lower surface of the underlying insulating layer 25R. The lower surface of this anode electrode pad 42AR is in contact with the anode substrate pad 13 of the circuit board 10 and electrically connected to it.

[0052] The anode pillar 45R is part of the vertical wiring 23A and is formed in a roughly rectangular prism shape with a central axis along the Z direction. It is constructed as a single-layer or multi-layer laminated structure of metals such as Au, Al, Cu, Ni (nickel), Pt, or Ti, or alloys thereof, and is electrically conductive. The anode pillar 45R is electrically connected to the anode electrode pad 42AR by contacting its lower surface. The upper surface of the anode pillar 45R forms the same plane as the upper surface of the interlayer insulating layer 26R, and this upper surface is electrically connected to the anode electrode pad 42AG (described in detail later) provided on the second thin film layer 20G by contacting it.

[0053] Furthermore, the anode pillar 45R is formed to connect the light-emitting element 21R and the vertical wiring 23A along the Y direction. Specifically, the anode pillar 45R is electrically connected to the anode layer 33R on the light-emitting element 21R side. The anode pillar 45R is also electrically connected to the anode electrode pad 42AR on the vertical wiring 23A side.

[0054] The cathode pillars 46BR and 46GR are parts of the vertical wiring 23B and 23G, respectively, and are formed in a rectangular prism shape with a central axis along the Z direction. They are constructed as a single-layer or multi-layer laminated structure of metals such as Au, Al, Cu, Ni, Pt, or Ti, or alloys thereof, and are electrically conductive. The lower surfaces of the cathode pillars 46BR and 46GR are in contact with the cathode electrode pads 42BR and 42GR, respectively, and are electrically connected. The upper surfaces of the cathode pillars 46BR and 46GR form the same plane as the upper surface of the interlayer insulating layer 26R, and these upper surfaces are in contact with the cathode electrode pads 42BG and 42GG (described in detail later) provided on the second thin film layer 20G, respectively, and are electrically connected.

[0055] The first thin film layer 20R configured in this way supplies power to the light-emitting element 21R via vertical wiring 23A and 23R, thereby causing the light-emitting element 21R to function as a red light-emitting element. At this time, the light-emitting element 21R emits light in the area corresponding to the light-emitting layer 32R when viewed from the Z direction, thereby emitting light with a wavelength of, for example, 601 to 780 [nm], i.e., red light.

[0056] Furthermore, the first thin film layer 20R electrically connects the anode substrate pad 13 of the circuit board 10 and the anode electrode pad 42AG provided on the second thin film layer 20G via vertical wiring 23A, thereby relaying the power supply. In addition, the first thin film layer 20R electrically connects the cathode substrate pads 12B and 12G of the circuit board 10 and the cathode electrode pads 42BG and 42GG provided on the second thin film layer 20G via vertical wiring 23B and 23G, respectively.

[0057] [1-3-3. Composition of the second thin film layer] As shown in Figures 2, 4, and 6, the second thin film layer 20G has an overall similar structure to the first thin film layer 20R (Figure 5), but some parts are different. Specifically, the second thin film layer 20G has the parts that constitute the light-emitting element 21G and each vertical wiring 23, as well as the underlay insulating layer 25G and the interlayer insulating layer 26G. Furthermore, the second thin film layer 20G has the light-emitting element 21G composed of a cathode layer 31G, a light-emitting layer 32G, and an anode layer 33G, and also has cathode lead-out wiring 43G and insulating layers 37AG and 37GG, which are parts that are greatly involved in the light-emitting part 22.

[0058] Furthermore, the second thin film layer 20G mainly comprises cathode electrode pads 42BG and 42GG, anode electrode pad 42AG, anode pillar 45G, and cathode pillar 46BG, which are portions related to each vertical wiring 23.

[0059] The underlayment insulating layer 25G, also called the base layer, is made of the same material as, for example, the underlayment insulating layer 25R and has sufficient insulating properties. Although the underlayment insulating layer 25G is formed as a uniformly flat thin film overall, openings 38BG, 38GG, and 38AG, which are rectangular prism-shaped holes penetrating in the Z direction, are formed at three locations on the -X, +X, and -Y directions of the light-emitting element 21G, that is, in the portions corresponding to the vertical wiring 23B, 23G, and 23A mentioned above.

[0060] The light-emitting element 21G is constructed by sequentially stacking the light-emitting layer 32G and the anode layer 33G on the +Z side of the underlying insulating layer 25G, from the -Z side toward the +Z side, and is configured as a thin film with a thickness of 3 [μm] or less in the Z direction, thus forming a thin-film inorganic LED overall. In addition, the light-emitting element 21G has a cathode layer 31G stacked on the +Z side near the +X side end of the n-type GaN layer 61G. The cathode layer 31G, light-emitting layer 32G, and anode layer 33G are all configured as single or multiple layers, and are thin films with flat top and bottom surfaces.

[0061] The anode layer 33G and the InGaN active layer 62G, p-type GaN layer 63G, and p-type InGaN absorption layer 64G of the light-emitting layer 32G are formed in a circular shape when viewed from the Z direction and are located approximately in the center of the pixel portion 8 in the X and Y directions. The AlN buffer layer 60G and n-type GaN layer 61G of the light-emitting layer 32G have a shape when viewed from the Z direction that combines a circular portion with the same shape as the anode layer 33G, InGaN active layer 62G, p-type GaN layer 63G, and p-type InGaN absorption layer 64G, with a roughly rectangular portion protruding from the circular portion in the +X direction, and the center of the circular portion is located approximately in the center of the pixel portion 8 in the X and Y directions. Furthermore, the circular portions of the anode layer 33G and the InGaN active layer 62G, p-type GaN layer 63G, and p-type InGaN absorption layer 64G within the light-emitting layer 32G are configured to have the same shape and size as the light-emitting layer 32R, anode layer 33R, and cathode layer 31R of the first thin film layer 20R (Figure 5) when viewed from the Z direction.

[0062] The cathode lead wire 43G is made of the same material as, for example, the cathode lead wire 43R. This cathode lead wire 43G is formed to connect the light-emitting element 21G and the vertical wiring 23G, generally along the X direction. Specifically, the cathode lead wire 43G is electrically connected to the cathode layer 31G on the light-emitting element 21G side. The cathode lead wire 43G is also electrically connected to the cathode electrode pad 42GG on the vertical wiring 23G side.

[0063] The insulating layer 37AG is made of the same material as the insulating layer 37AR, for example, and has electrical insulating properties. This insulating layer 37AG electrically insulates the anode pillar 45G and the light-emitting layer 32G to prevent short circuits. The insulating layer 37GG is made of the same material as the insulating layer 37AR, for example, and has electrical insulating properties. This insulating layer 37GG electrically insulates the cathode lead wiring 43G and the light-emitting layer 32G to prevent short circuits.

[0064] The interlayer insulating layer 26G is formed to fill the +Z direction portion of the light-emitting element 21G and the cathode lead-out wiring 43G. This interlayer insulating layer 26G is made of the same material as, for example, the interlayer insulating layer 26R and has electrical insulating properties. The upper surface of the interlayer insulating layer 26G is formed to be extremely flat, with a surface roughness Rz of 10 [nm] or less.

[0065] The cathode electrode pads 42BG and 42GG are parts of the vertical wiring 23B and 23G, respectively, and are made of the same material as, for example, the cathode electrode pads 42RR, 42GR, and 42BR, and are conductive. The cathode electrode pads 42BG and 42GG are formed to cover the openings 38BG and 38GG formed in the underlying insulating layer 25G, respectively, and their lower surfaces form the same plane as the lower surface of the underlying insulating layer 25G. The lower surfaces of the cathode electrode pads 42BG and 42GG are in contact with the upper surfaces of the cathode pillars 46BR and 46GR in the first thin film layer 20R, respectively, and are electrically connected, while the upper surfaces are in contact with the cathode pillar 46BG and the cathode lead wiring 43G, respectively, and are electrically connected.

[0066] The anode electrode pad 42AG is part of the vertical wiring 23A and is made of the same material as, for example, the anode electrode pad 42AR, and is conductive. The anode electrode pad 42AG is also formed to cover the opening 38AG formed in the underlying insulating layer 25G, and its lower surface forms the same plane as the lower surface of the underlying insulating layer 25G. The anode electrode pad 42AG is electrically connected by contacting the upper surface of the anode pillar 45R in the first thin film layer 20R with its lower surface, and by contacting the anode pillar 45G with its upper surface.

[0067] The anode pillar 45G is part of the vertical wiring 23A and is formed in a substantially rectangular prism shape with a central axis along the Z direction. It is made of the same material as, for example, the anode pillar 45R and is conductive. The anode pillar 45G is electrically connected to the anode electrode pad 42AG by contacting its lower surface. The upper surface of the anode pillar 45G forms the same plane as the upper surface of the interlayer insulating layer 26G, and this upper surface is electrically connected to the anode electrode pad 42AB (described in detail later) provided on the third thin film layer 20B by contacting it.

[0068] Furthermore, the anode pillar 45G is formed to connect the light-emitting element 21G and the vertical wiring 23A along the Y direction. Specifically, the anode pillar 45G is electrically connected to the anode layer 33G on the light-emitting element 21G side. The anode pillar 45G is also electrically connected to the anode electrode pad 42AG on the vertical wiring 23A side.

[0069] The cathode pillar 46BG is part of the vertical wiring 23G and is formed in a rectangular prism shape with a central axis along the Z direction. It is made of the same material as, for example, the cathode pillars 46BR and 46GR and is conductive. The cathode pillar 46BG is electrically connected to the cathode electrode pad 42BG by contacting its lower surface. The upper surface of the cathode pillar 46BG forms the same plane as the upper surface of the interlayer insulating layer 26G, and this upper surface is electrically connected to the cathode electrode pad 42BB (described in detail later) provided on the third thin film layer 20B by contacting it.

[0070] The second thin film layer 20G configured in this way supplies power to the light-emitting element 21G via vertical wiring 23A and 23G, thereby causing the light-emitting element 21G to function as a green light-emitting element. At this time, the light-emitting element 21G emits light in the area corresponding to the light-emitting layer 32G when viewed from the Z direction, thereby emitting light with a wavelength of, for example, 491 to 600 [nm], i.e., green light.

[0071] Furthermore, the second thin film layer 20G electrically connects the anode pillar 45R of the first thin film layer 20R and the anode electrode pad 42AB of the third thin film layer 20B via vertical wiring 23A, thereby relaying the power supply. In addition, the second thin film layer 20G electrically connects the cathode pillar 46BR of the first thin film layer 20R and the cathode electrode pad 42BB provided on the third thin film layer 20B via vertical wiring 23B.

[0072] [1-3-4. Composition of the third thin film layer] As shown in Figures 2, 3, and 6, the third thin film layer 20B has an overall similar structure to the second thin film layer 20G (Figure 4), but some parts are different. Specifically, the third thin film layer 20B has the parts that constitute the light-emitting element 21B and each vertical wiring 23, as well as the underlay insulating layer 25B and the interlayer insulating layer 26B. Furthermore, the third thin film layer 20B has the light-emitting element 21B composed of a cathode layer 31B, a light-emitting layer 32B and an anode layer 33B, and insulating layers 37AB and 37BB which are parts that are greatly involved with the light-emitting part 22.

[0073] Furthermore, the third thin film layer 20B mainly comprises a cathode electrode pad 42BB, an anode electrode pad 42AB, an anode pillar 45B, and a cathode lead-out wiring 43B, which are portions related to each vertical wiring 23.

[0074] The underlying insulating layer 25B, also called the base layer, is made of the same material as, for example, the underlying insulating layer 25G and has sufficient insulating properties. Although the underlying insulating layer 25B as a whole is formed as a uniformly flat thin film, openings 38BB and 38AB, which are rectangular prism-shaped holes penetrating in the Z direction, are formed at two locations on the -X and -Y directions of the light-emitting element 21B, that is, in the portions corresponding to the vertical wiring 23B and 23A described above.

[0075] The light-emitting element 21B is constructed by sequentially laminating the light-emitting layer 32B and the anode layer 33B on the +Z side of the underlying insulating layer 25B, from the -Z side toward the +Z side, and is configured as a thin film with a thickness of 3 [μm] or less in the Z direction, thus forming a thin-film inorganic LED overall. The light-emitting element 21B also has a cathode layer 31B laminated on the +Z side near the -X side end of the n-type GaN layer 71B. The cathode layer 31B, light-emitting layer 32B, and anode layer 33B are configured as single or multiple layers, with flat top and bottom surfaces forming thin films.

[0076] The anode layer 33B and the InGaN active layer 72B and p-type GaN layer 73B of the light-emitting layer 32B are formed in a circular shape when viewed from the Z direction and are located approximately in the center of the pixel portion 8 in terms of the X and Y directions. The AlN buffer layer 70B and n-type GaN layer 71B of the light-emitting layer 32B have a shape that combines a circular portion identical in shape to the InGaN active layer 72B and p-type GaN layer 73B when viewed from the Z direction with a roughly rectangular portion protruding from the circular portion in the -X direction, with the center of the circular portion located approximately in the center of the pixel portion 8 in terms of the X and Y directions. Furthermore, the circular portions of the anode layer 33B and the InGaN active layer 72B and p-type GaN layer 73B of the light-emitting layer 32B are configured to have the same shape and size as the light-emitting layer 32R, anode layer 33R, and cathode layer 31R of the first thin film layer 20R (Figure 5) when viewed from the Z direction. Therefore, the light-emitting layer 32R, anode layer 33R, and cathode layer 31R in the first thin film layer 20R (Figures 5 and 6), the circular portion of the anode layer 33G, the InGaN active layer 62G, the p-type GaN layer 63G, and the p-type InGaN absorption layer 64G in the second thin film layer 20G (Figures 4 and 6), and the circular portion of the anode layer 33B, the InGaN active layer 72B, and the p-type GaN layer 73B in the third thin film layer 20B (Figures 3 and 6) are all configured to be the same shape and size when viewed from the Z direction.

[0077] The cathode lead wire 43B is made of the same material as, for example, the cathode lead wire 43G. This cathode lead wire 43B is formed to connect the light-emitting element 21B and the vertical wiring 23B, generally along the X direction. Specifically, the cathode lead wire 43B is electrically connected to the cathode layer 31B on the light-emitting element 21B side. The cathode lead wire 43B is also electrically connected to the cathode electrode pad 42BB on the vertical wiring 23B side.

[0078] The insulating layer 37AB is made of the same material as the insulating layer 37AG, for example, and has electrical insulating properties. This insulating layer 37AB electrically insulates the anode pillar 45B and the light-emitting layer 32B to prevent short circuits. The insulating layer 37BB is made of the same material as the insulating layer 37AG, for example, and has electrical insulating properties. This insulating layer 37BB electrically insulates the cathode lead wiring 43B and the light-emitting layer 32B to prevent short circuits.

[0079] The interlayer insulating layer 26B is formed to fill the +Z direction portion of the light-emitting element 21B and the cathode lead-out wiring 43B. This interlayer insulating layer 26B is made of the same material as, for example, the interlayer insulating layer 26G and has electrical insulating properties. The upper surface of the interlayer insulating layer 26B is formed to be extremely flat, with a surface roughness Rz of 10 [nm] or less.

[0080] The cathode electrode pad 42BB is part of the vertical wiring 23B and is made of the same material as, for example, the cathode electrode pads 42BG and 42GG, and is conductive. The cathode electrode pad 42BB is formed to cover the opening 38BB formed in the underlying insulating layer 25B, and its lower surface forms the same plane as the lower surface of the underlying insulating layer 25B. The cathode electrode pad 42BB is electrically connected by contacting the upper surface of the cathode pillar 46BG in the second thin film layer 20G with its lower surface, and by contacting the cathode lead wiring 43B with its upper surface.

[0081] The anode electrode pad 42AB is part of the vertical wiring 23A and is made of the same material as, for example, the anode electrode pad 42AG, and is conductive. The anode electrode pad 42AB is also formed to cover the opening 38AB formed in the underlying insulating layer 25B, and its lower surface forms the same plane as the lower surface of the underlying insulating layer 25B. The anode electrode pad 42AB is electrically connected by contacting the upper surface of the anode pillar 45G in the second thin film layer 20G with its lower surface, and by contacting the anode pillar 45B with its upper surface.

[0082] The anode pillar 45B is part of the vertical wiring 23A and is formed in a roughly rectangular prism shape with a central axis along the Z direction. It is made of the same material as, for example, the anode pillar 45G and is conductive. The anode pillar 45B is electrically connected to the anode electrode pad 42AB by contacting its lower surface with it. The anode pillar 45B is also formed to connect the light-emitting element 21B and the vertical wiring 23A along the Y direction. Specifically, the anode pillar 45B is electrically connected to the anode layer 33B on the light-emitting element 21B side. The anode pillar 45B is also electrically connected to the anode electrode pad 42AB on the vertical wiring 23A side.

[0083] The third thin film layer 20B configured in this way supplies power to the light-emitting element 21B via vertical wiring 23A and 23B, thereby causing the light-emitting element 21B to function as a blue light-emitting element. At this time, the light-emitting element 21B emits light in the area corresponding to the light-emitting layer 32B when viewed from the Z direction, thereby emitting light with a wavelength of, for example, 400-490 nm, i.e., blue light.

[0084] [1-4. Regarding the configuration and bandgap of light-emitting elements] [1-4-1. Configuration and bandgap of the third thin film layer light-emitting element] As described above, the light-emitting element 21B is composed of a cathode layer 31B, a light-emitting layer 32B, and an anode layer 33B. The cathode layer 31B is made of a metal such as Al or Ti and is conductive. The anode layer 33B is made of a material such as ITO, ZnO (zinc oxide), or TiO2 (titanium oxide) and is conductive.

[0085] The light-emitting layer 32B is constructed by sequentially stacking an AlN buffer layer 70B, an n-type GaN layer 71B, an InGaN active layer 72B, and a p-type GaN layer 73B from the -Z direction to the +Z direction. The AlN buffer layer 70B has a bandgap (band gap) of 6 [eV] and transmits all visible light. The InGaN active layer 72B has a composition of In0.1Ga0.9N to In0.2Ga0.8N, a bandgap of 2.67 to 3.06 [eV], and a peak emission wavelength of 405 to 465 [nm]. In this embodiment, the InGaN active layer 72B has a composition of In0.22Ga0.78N, a bandgap of 2.67 [eV], and a peak emission wavelength of 465 [nm].

[0086] [1-4-2. Configuration and bandgap of the second thin film layer's light-emitting element] As described above, the light-emitting element 21G is composed of a cathode layer 31G, a light-emitting layer 32G, and an anode layer 33G. The cathode layer 31G is made of a metal such as Al or Ti and is conductive. The anode layer 33G is made of a metal such as ITO, ZnO, or TiO2 and is conductive.

[0087] The light-emitting layer 32G is constructed by sequentially stacking an AlN buffer layer 60G, an n-type GaN layer 61G, an InGaN active layer 62G, a p-type GaN layer 63G, and a p-type InGaN absorption layer 64G, from the -Z direction to the +Z direction. The AlN buffer layer 60G has a band gap of 6 [eV] and transmits all visible light. The InGaN active layer 62G has a composition of In0.42Ga0.58N~In0.35Ga0.65N, a band gap of 2.25~2.48 [eV], and a peak emission wavelength of 500~550 [nm]. In this embodiment, the InGaN active layer 62G has a composition of In0.39Ga0.61N, a band gap of 2.38 [eV], and a peak emission wavelength of 520 [nm].

[0088] The p-type InGaN absorption layer 64G is a light-absorbing layer that absorbs light emitted from the third thin film layer 20B, which is the upper layer over the second thin film layer 20G, and diffused in the -Z direction. This p-type InGaN absorption layer 64G has a composition of In0.27Ga0.73N to In0.35Ga0.65N and a band gap of 2.48 to 2.67 [eV], and almost completely absorbs blue light emission. In this embodiment, the p-type InGaN absorption layer 64G has a composition of In0.3Ga0.7N and a band gap of 2.61 [eV].

[0089] Here, light passes through an object with a band gap larger than its own because it does not have enough energy to excite it. On the other hand, light is absorbed by an object with a band gap smaller than its own because it has enough energy to excite it.

[0090] Thus, the band gap of the p-type InGaN absorption layer 64G (2.61 eV) is larger than the band gap of the InGaN active layer 62G (2.38 eV) and the band gap of the AlGaInP active layer 51R of the first thin film layer 20R (1.92 eV) (described later). For this reason, the p-type InGaN absorption layer 64G allows the green light emitted from the InGaN active layer 62G and the red light emitted from the AlGaInP active layer 51R of the first thin film layer 20R to pass through in the +Z direction without being absorbed.

[0091] On the other hand, the band gap of the p-type InGaN absorption layer 64G (2.61 eV) is less than or equal to the band gap of the InGaN active layer 72B of the third thin film layer 20B (2.67 eV). Therefore, the p-type InGaN absorption layer 64G absorbs the blue light emitted from the InGaN active layer 72B.

[0092] The composition of the p-type InGaN absorption layer 64G is just an example, and can be adjusted within a band gap range that is larger than that of the InGaN active layer 62G and smaller than or equal to that of the InGaN active layer 72B. Furthermore, the closer the band gap of the p-type InGaN absorption layer 64G is to that of the InGaN active layer 72B, the closer the excitation light will be to the wavelength of the blue light emitted from the InGaN active layer 72B, even if the p-type InGaN absorption layer 64G is excited by the blue light emitted from the InGaN active layer 72B. For this reason, the closer the band gap of the p-type InGaN absorption layer 64G is to that of the InGaN active layer 72B, the more effective the LED display device 1 can be in preventing the mixing of green light with the blue light emitted from the InGaN active layer 72B. For this reason, it is preferable that the band gap of the p-type InGaN absorption layer 64G is closer to that of the InGaN active layer 72B than to that of the InGaN active layer 62G.

[0093] Therefore, the effect of preventing color mixing of blue light emission can be maximized when the p-type InGaN absorption layer 64G has the same band gap as the InGaN active layer 72B. However, even if the band gap of the p-type InGaN absorption layer 64G is set to be the same as that of the InGaN active layer 72B, if the band gap of the p-type InGaN absorption layer 64G becomes larger than that of the InGaN active layer 72B due to manufacturing errors or the like, the blue light emitted from the InGaN active layer 72B will pass through the p-type InGaN absorption layer 64G without being absorbed. For this reason, taking such manufacturing errors into consideration, it is preferable to set the band gap of the p-type InGaN absorption layer 64G to be as close as possible to that of the InGaN active layer 72B, and to be less than or equal to that of the InGaN active layer 72B.

[0094] [1-4-3. Light-emitting element configuration and bandgap of the first thin film layer] As described above, the light-emitting element 21R is constructed by sequentially stacking a cathode layer 31R, a light-emitting layer 32R, and an anode layer 33R so that they overlap from the -Z direction to the +Z direction. The cathode layer 31R is made of, for example, Pd (palladium), gold germanium (AuGe), or Au, and is conductive. The anode layer 33R is made of, for example, ITO, ZnO, or TiO2, and is conductive.

[0095] The light-emitting layer 32R is constructed by sequentially stacking an n-type AlInP layer 50R, an AlGaInP active layer 51R, a p-type AlInP layer 52R, and a p-type GaP absorption layer 53R from the -Z direction to the +Z direction. The AlGaInP active layer 51R has a composition of (Al0.0Ga1.0)0.5In0.5P to (Al0.7Ga0.3)0.5In0.5P, a band gap of 1.91 to 2.23 [eV], and a peak emission wavelength of 556 to 650 [nm]. In this embodiment, the AlGaInP active layer 51R has a composition of (Al0.05Ga0.95)0.5In0.5P, a band gap of 1.92 [eV], and a peak emission wavelength of 647 [nm].

[0096] The p-type GaP absorption layer 53R is a light absorption layer that absorbs light emitted from the second thin film layer 20G and the third thin film layer 20B, which are upper layers over the first thin film layer 20R, and diffused in the -Z direction. This p-type GaP absorption layer 53R almost completely absorbs blue and green light emission. In this embodiment, the p-type GaP absorption layer 53R is made of GaP with a band gap of 2.26 [eV].

[0097] Thus, the band gap of the p-type GaP absorption layer 53R (2.26 [eV]) is larger than the band gap of the AlGaInP active layer 51R (1.92 [eV]). For this reason, the p-type GaP absorption layer 53R allows the red light emitted from the AlGaInP active layer 51R to pass through in the +Z direction without absorption.

[0098] On the other hand, the band gap of the p-type GaP absorption layer 53R (2.26 [eV]) is less than or equal to the band gap of the InGaN active layer 72B of the third thin film layer 20B (2.67 [eV]), and also less than or equal to the band gap of the InGaN active layer 62G of the second thin film layer 20G (2.38 [eV]). Therefore, the p-type GaP absorption layer 53R absorbs the blue light emitted from the InGaN active layer 72B and the green light emitted from the InGaN active layer 62G.

[0099] The composition of the p-type GaP absorption layer 53R is just an example and can be adjusted within a band gap range that is larger than that of the AlGaInP active layer 51R and less than or equal to the InGaN active layer 62G (i.e., less than or equal to the InGaN active layer 72B). Furthermore, the closer the band gap of the p-type GaP absorption layer 53R is to that of the InGaN active layer 62G, the closer the excitation light of the p-type GaP absorption layer 53R is to that of the InGaN active layer 62G will be to that of the green light emitted from the InGaN active layer 62G. For this reason, the closer the band gap of the p-type GaP absorption layer 53R is to that of the InGaN active layer 62G, the more effective the LED display device 1 can be in preventing the mixing of red light with the green light emitted from the InGaN active layer 62G. For this reason, it is preferable that the band gap of the p-type GaP absorption layer 53R is closer to that of the InGaN active layer 62G than that of the AlGaInP active layer 51R.

[0100] Therefore, the effect of preventing mixing of green emission can be maximized when the p-type GaP absorption layer 53R has the same band gap as the InGaN active layer 62G. However, even if the band gap of the p-type GaP absorption layer 53R is set to be the same as that of the InGaN active layer 62G, if the band gap of the p-type GaP absorption layer 53R becomes larger than that of the InGaN active layer 62G due to manufacturing errors or the like, the green emission emitted from the InGaN active layer 62G will pass through the p-type GaP absorption layer 53R without being absorbed. For this reason, taking such manufacturing errors into consideration, it is preferable to set the band gap of the p-type GaP absorption layer 53R to be as close as possible to that of the InGaN active layer 62G, and to be less than or equal to that of the InGaN active layer 62G.

[0101] [1-5. Method for manufacturing the LED display unit] Next, an example of a method for manufacturing the LED display unit 2 in the LED display device 1 will be explained using Figures 7 and 8. Incidentally, both Figures 7 and 8 are schematic cross-sectional views showing the state where the +Z direction is oriented upwards. For the sake 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. Note that for the sake of drawing, Figures 7 and 8 are cross-sectional views, but hatching has not been added.

[0102] [1-5-1. Method for manufacturing the second thin film layer] First, the manufacturing method for the second thin film layer 20G will be explained with reference to Figure 7. First, as shown in Figure 7(A), the manufacturing apparatus 60 epitaxially grows an AlN buffer layer 60G on the upper side of a silicon substrate 80G (crystal orientation

[0111] ), then epitaxially grows an n-type GaN layer 61G on the upper side of the AlN buffer layer 60G, then epitaxially grows an InGaN active layer 62G on the upper side of the n-type GaN layer 61G, then epitaxially grows a p-type GaN layer 63G on the upper side of the InGaN active layer 62G, and then epitaxially grows a p-type InGaN absorption layer 64G on the upper side of the p-type GaN layer 63G. As a result, the manufacturing apparatus 60 forms an LED layer consisting of a p-type GaN layer 63G, an InGaN active layer 62G, and an n-type GaN layer 61G, which are arranged in a p-type-active layer-n-type configuration.

[0103] Next, the manufacturing apparatus 60 stacks an anode layer 33G on top of the p-type InGaN absorption layer 64G. At this time, the manufacturing apparatus 60 stacks the anode layer 33G by sputtering a transparent conductive film such as ITO, ZnO, or TiO2 to ensure light transmittance. In this way, the manufacturing apparatus 60 obtains ohmic contact of the p-type electrode. The manufacturing apparatus 60 is not limited to this, however, may also form a Ni film of several nm thickness to reduce the resistance with the p-type InGaN absorption layer 64G before forming the transparent electrode film. Alternatively, the manufacturing apparatus 60 may form the anode layer 33G with a thin metal film layer such as NiAu of about 10 nm thickness.

[0104] Next, as shown in Figure 7(B), the manufacturing apparatus 60 performs dry etching on the laminated substrate shown in Figure 7(A) to form a circular portion and a substantially rectangular portion protruding from the circular portion. At this time, the manufacturing apparatus 60 performs dry etching of the rectangular portion from above up to the n-type GaN layer 61G in order to provide the cathode layer 31G on the n-type GaN layer 61G.

[0105] Next, the manufacturing apparatus 60 performs wet etching horizontally (crystal orientation

[0100] direction) with potassium hydroxide (KOH) on a portion of the sacrificial layer portion 81G, indicated by the dashed line, which is the upper surface of the silicon substrate 80G in contact with the AlN buffer layer 60G. The manufacturing apparatus 60 also temporarily stops the etching process and flows resist from the surrounding area between the silicon substrate 80G and the AlN buffer layer 60G, exposing and removing any excess resist to form a resist support layer 82G between the silicon substrate 80G and the AlN buffer layer 60G. As a result, the remaining portion of the sacrificial layer portion 81G of the silicon substrate 80G that was not etched and the resist support layer 82G support the layers located above them. Next, the manufacturing apparatus 60 completes the etching of the silicon substrate 80G by etching the remaining portion of the sacrificial layer portion 81G that was not etched.

[0106] Next, as shown in Figure 7(C), the manufacturing apparatus 60 peels off the laminated substrate, which consists of an AlN buffer layer 60G, an n-type GaN layer 61G, an InGaN active layer 62G, a p-type GaN layer 63G, a p-type InGaN absorption layer 64G, and an anode layer 33G, from the silicon substrate 80G using a stamp or the like (not shown), and removes the residue of the resist support layer 82G that adhered during peeling to obtain a green LED substrate 83G.

[0107] Next, as shown in Figure 7(D), the manufacturing apparatus 60 attaches the green LED substrate 83G shown in Figure 7(D) to the upper surface of the LED growth substrate 84G, which is made of silicon (Si), by intermolecular forces. The substrate consists of a sacrificial layer 85G made of SiO2 and an underlayment insulating layer 25G sequentially stacked on top of it. At this time, the manufacturing apparatus 60 smooths the lower surface of the AlN buffer layer 60G to a surface roughness of 10 [nm] or less by CMP, and similarly smooths the upper surface of the underlayment insulating layer 25G before attaching the green LED substrate 83G to the upper surface of the underlayment insulating layer 25G. Next, the manufacturing apparatus 60 forms a cathode layer 31G on the upper surface of the n-type GaN layer 61G. Next, the manufacturing apparatus 60 forms openings 38BG, 38GG, and 38AG in the underlayment insulating layer 25G by etching.

[0108] Next, as shown in Figure 7(E), the manufacturing apparatus 60 forms cathode electrode pads 42BG, 42GG and anode electrode pad 42AG in the respective openings 38BG, 38GG, and 38AG, such that their edges rest on the upper surface of the underlying insulating layer 25G.

[0109] Next, the manufacturing apparatus 60 ensures insulation by forming an insulating layer 37AG, and then forms an anode pillar 45G on its upper side to connect the anode electrode pad 42AG with the anode layer 33G. The manufacturing apparatus 60 also ensures insulation by forming an insulating layer 37GG, and then forms a cathode lead wire 43G on its upper side to connect the cathode electrode pad 42GG with the cathode layer 31G. Furthermore, the manufacturing apparatus 60 forms a cathode pillar 46BG on its upper side of the cathode electrode pad 42BG. Finally, the manufacturing apparatus 60 covers the entire assembly with an interlayer insulating layer 26G.

[0110] Next, the manufacturing apparatus 60 removes the sacrificial layer 85G by etching it, thereby peeling off the LED growth substrate 84G. As a result, the cathode electrode pads 42BG and 42GG and the anode electrode pad 42AG are exposed from the lower surface of the underlying insulating layer 25G. The manufacturing apparatus 60 then forms a second thin film layer 20G.

[0111] [1-5-2. Method for manufacturing the third thin film layer] Next, the manufacturing method for the third thin film layer 20B will be described. The manufacturing method for the third thin film layer 20B differs from that for the manufacturing method for the second thin film layer 20G in that the step of stacking the p-type InGaN absorption layer 64G is omitted. However, the other steps are almost the same, so a detailed explanation will be omitted.

[0112] [1-5-3. Method for manufacturing the first thin film layer] Next, the manufacturing method for the first thin film layer 20R will be explained with reference to Figure 8. First, as shown in Figure 8(A), the manufacturing apparatus 60 epitaxially grows an AlAs sacrificial layer 87R on top of a GaAs substrate 86R (crystal orientation

[0111] ), then epitaxially grows an n-type AlInP layer 50R on top of the AlAs sacrificial layer 87R, then epitaxially grows an AlGaInP active layer 51R on top of the n-type AlInP layer 50R, then epitaxially grows a p-type AlInP layer 52R on top of the AlGaInP active layer 51R, and then epitaxially grows a p-type GaP absorption layer 53R on top of the p-type AlInP layer 52R. As a result, the manufacturing apparatus 60 forms an LED layer consisting of a p-type layer, an active layer, and an n-type layer using the p-type AlInP layer 52R, the AlGaInP active layer 51R, and the n-type AlInP layer 50R.

[0113] Next, the manufacturing apparatus 60 stacks an anode layer 33R on top of the p-type GaP absorption layer 53R. At this time, the manufacturing apparatus 60 stacks the anode layer 33R by sputtering a transparent conductive film such as ITO, ZnO, or TiO2 to ensure light transmittance. In this way, the manufacturing apparatus 60 obtains ohmic contact of the p-type electrode. The manufacturing apparatus 60 is not limited to this, however, may also form a Ni film of several nm thickness to reduce the resistance with the p-type GaP absorption layer 53R before forming the transparent electrode film. Alternatively, the manufacturing apparatus 60 may form the anode layer 33R with a thin metal film layer such as NiAu of about 10 nm thickness.

[0114] Next, as shown in Figure 8(B), the manufacturing apparatus 60 forms a circular portion on the laminated substrate shown in Figure 8(A) by performing dry etching.

[0115] Next, the manufacturing apparatus 60 performs wet etching in the horizontal direction (crystal orientation

[0100] direction) on a portion of the AlAs sacrificial layer 87R using a hydrofluoric acid-containing solution. The manufacturing apparatus 60 also temporarily stops the etching process midway through and flows resist from the periphery between the GaAs substrate 86R and the n-type AlInP layer 50R, exposing and removing any excess resist to form a resist support layer 88R between the GaAs substrate 86R and the n-type AlInP layer 50R. As a result, the remaining portion of the AlAs sacrificial layer 87R that was not etched and the resist support layer 88R support the layers located above them. Next, the manufacturing apparatus 60 completes the etching of the AlAs sacrificial layer 87R by etching the AlAs sacrificial layer 87R.

[0116] Next, as shown in Figure 8(C), the manufacturing apparatus 60 peels the laminated substrate, in which the n-type AlInP layer 50R, AlGaInP active layer 51R, p-type AlInP layer 52R, p-type GaP absorption layer 53R, and anode layer 33R are stacked, from the GaAs substrate 86R using a stamp or the like (not shown), and removes any residue of the resist support layer 88R that adhered during peeling. Next, the manufacturing apparatus 60 smooths the lower surface of the n-type AlInP layer 50R to a surface roughness of 10 [nm] or less by CMP or the like, and then forms a cathode layer 31R on the underside of the n-type AlInP layer 50R. In this way, the manufacturing apparatus 60 obtains a red LED substrate 89R.

[0117] Next, as shown in Figure 8(D), the manufacturing apparatus 60 attaches the red LED substrate 89R shown in Figure 8(C) to the substrate, which has a base insulating layer 25R and cathode lead wiring 43R sequentially laminated on top of a sacrificial layer 90R made of SiO2, by intermolecular forces. At this time, the manufacturing apparatus 60 smooths the lower surface of the cathode layer 31R to a surface roughness of 10 [nm] or less by CMP or the like, and smooths the upper surface of the cathode lead wiring 43R to a surface roughness of 10 [nm] or less by CMP or the like, before attaching the red LED substrate 89R to the top of the cathode lead wiring 43R. Next, the manufacturing apparatus 60 removes most of the cathode lead wiring 43R by patterning. Next, the manufacturing apparatus 60 forms openings 38BR, 38GR, 38RR and 38AR in the base insulating layer 25R by etching.

[0118] Next, as shown in Figure 8(E), the manufacturing apparatus 60 forms cathode electrode pads 42BR, 42GR, and 42RR (Figure 5) and anode electrode pad 42AR in each of the openings 38BR, 38GR, 38RR, and 38AR such that their edges rest on the upper surface of the underlying insulating layer 25R.

[0119] Next, the manufacturing apparatus 60 ensures insulation by forming an insulating layer 37R, and then forms an anode pillar 45R on top of it to create electrical conductivity between the anode electrode pad 42AR and the anode layer 33R. The manufacturing apparatus 60 also forms cathode pillars 46BR and 46GR on top of the cathode electrode pads 42BR and 42GR, respectively. Furthermore, the manufacturing apparatus 60 covers the entire structure with an interlayer insulating layer 26R.

[0120] Next, the manufacturing apparatus 60 removes the sacrificial layer 90R by etching it. This exposes the cathode electrode pads 42BR, 42GR, and 42RR and the anode electrode pad 42AR from the lower surface of the underlying insulating layer 25R. As a result, the manufacturing apparatus 60 forms the first thin film layer 20R.

[0121] [1-5-4. Lamination bonding process] Next, the lamination bonding process, in which the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B manufactured by the manufacturing method described above are laminated onto the circuit board 10, will be explained with reference to Figure 6.

[0122] First, the manufacturing apparatus 60 bonds the first thin film layer 20R to the upper surface of the circuit board 10 by intermolecular forces using a known bonding method. Next, the manufacturing apparatus 60 bonds the second thin film layer 20G to the upper surface of the first thin film layer 20R bonded to the circuit board 10 by intermolecular forces using a known bonding method. Next, the manufacturing apparatus 60 bonds the third thin film layer 20B to the upper surface of the second thin film layer 20G bonded to the first thin film layer 20R by intermolecular forces using a known bonding method.

[0123] [1-6. Effects, etc.] In the above configuration, the LED display device 1 is configured to sequentially stack a first thin film layer 20R, a second thin film layer 20G, and a third thin film layer 20B, each emitting red (R), green (G), and blue (B) light along the emission direction E from the -Z direction to the +Z direction. In this way, the LED display device 1 places light with a small band gap and long wavelength on the lower layer side (-Z direction side) and light with a large band gap and short wavelength on the upper layer side (+Z direction side). By allowing the light from the lower thin film layer 20 with a long wavelength to pass through the upper thin film layer 20 with a large band gap, the LED display device 1 mixes the three RGB colors of light to display full color.

[0124] Furthermore, the LED display device 1 is provided with a p-type GaP absorption layer 53R between the AlGaInP active layer 51R of the first thin film layer 20R and the InGaN active layer 62G of the second thin film layer 20G. The p-type GaP absorption layer 53R has a band gap (2.26 eV) that is larger than the band gap (1.92 eV) of the AlGaInP active layer 51R and less than or equal to the band gap (2.38 eV) of the InGaN active layer 62G. As a result, the LED display device 1 can absorb the green light emitted from the InGaN active layer 62G and diffused to the lower layer (-Z direction) with the p-type GaP absorption layer 53R, preventing it from reaching the AlGaInP active layer 51R of the light-emitting layer 32R. This prevents the AlGaInP active layer 51R of the light-emitting layer 32R from being excited by the green light and generating excitation light.

[0125] Furthermore, the LED display device 1 is provided with a p-type InGaN absorption layer 64G between the InGaN active layer 62G of the second thin film layer 20G and the InGaN active layer 72B of the third thin film layer 20B. The p-type InGaN absorption layer 64G has a band gap (2.61 eV) that is larger than the band gap (2.38 eV) of the InGaN active layer 62G and less than or equal to the band gap (2.67 eV) of the InGaN active layer 72B. As a result, the LED display device 1 can absorb the blue light emitted from the InGaN active layer 72B and diffused to the lower layer (-Z direction) with the p-type InGaN absorption layer 64G, preventing it from reaching the InGaN active layer 62G of the light-emitting layer 32G. This prevents the InGaN active layer 62G of the light-emitting layer 32G from being excited by the blue light and generating excitation light.

[0126] In other words, the LED display device 1 is provided with a light-absorbing layer between the active layer of the lower thin film layer 20 and the active layer of the upper thin film layer 20, having a band gap that is larger than the band gap of the active layer of the lower thin film layer 20 and smaller than the band gap of the active layer of the upper thin film layer 20. As a result, the LED display device 1 can absorb light emitted from the active layer of the upper thin film layer 20 and diffused to the lower side (-Z direction) with the light-absorbing layer, preventing it from reaching the active layer of the lower thin film layer 20. This prevents the LED display device 1 from generating excitation light by the active layer of the lower thin film layer 20 due to light from the active layer of the upper thin film layer 20. Thus, the LED display device 1 can prevent mixing of colors due to excitation light of other colors, especially when emitting RGB monochromatic light, preventing color gamut shifts and saturation reductions caused by mixing, and widening the reproducible color gamut.

[0127] Furthermore, the LED display device 1 is configured such that a p-type InGaN absorption layer 64G, which absorbs blue light emitted from the InGaN active layer 72B of the third thin film layer 20B, is placed on the second thin film layer 20G located on the lower side (-Z direction side) of the third thin film layer 20B.

[0128] Similarly, the LED display device 1 is configured such that a p-type GaP absorption layer 53R, which absorbs green light emitted from the InGaN active layer 62G of the second thin film layer 20G, is placed on the first thin film layer 20R located on the lower side (-Z direction side) of the third thin film layer 20B.

[0129] In other words, the LED display device 1 is configured to place a light-absorbing layer that absorbs light emitted from the active layer on a thin film layer 20 located below the thin film layer 20 on which the active layer is provided. As a result, in the case of the second thin film layer 20G, the p-type InGaN absorption layer 64G is formed above the InGaN active layer 62G in the LED display device 1, and in the case of the first thin film layer 20R, the p-type GaP absorption layer 53R is formed above the AlGaInP active layer 51R. This allows the LED display device 1 to easily form films in the film deposition process of the light-emitting layers 32G and 32R, and prevents a decrease in crystallinity.

[0130] Furthermore, the LED display device 1 sets the band gap of the p-type InGaN absorption layer 64G of the second thin film layer 20G to a value closer to the band gap of the InGaN active layer 72B of the third thin film layer 20B, which is located on the upper side (+Z direction) of the p-type InGaN absorption layer 64G, than the band gap of the InGaN active layer 62G, which is located on the lower side (-Z direction) of the p-type InGaN absorption layer 64G.

[0131] Similarly, the LED display device 1 sets the band gap of the p-type GaP absorption layer 53R of the first thin film layer 20R to a value closer to the band gap of the InGaN active layer 62G of the second thin film layer 20G, which is located above the p-type GaP absorption layer 53R, than to the band gap of the AlGaInP active layer 51R, which is located below the p-type GaP absorption layer 53R.

[0132] In other words, the LED display device 1 sets the band gap of the light-absorbing layer to a value closer to the band gap of the active layer located above the light-absorbing layer than the band gap of the active layer located below the light-absorbing layer.

[0133] Therefore, even if the light-absorbing layer of the LED display device 1 is excited by light emitted from the active layer located above the light-absorbing layer, the excitation light can be made to have a wavelength close to that of the light emitted from the active layer located above the light-absorbing layer. As a result, the LED display device 1 can enhance the effect of preventing the excitation light of the light-absorbing layer from mixing with the light emitted from the active layer located above the light-absorbing layer, thereby suppressing a decrease in color purity.

[0134] According to the above configuration, the LED display device 1 according to the first embodiment comprises, when the first layer is a first thin film layer 20R, the second layer is a second thin film layer 20G, and the first light absorption layer is a p-type GaP absorption layer 53R, the first thin film layer 20R as the first layer has an AlGaInP active layer 51R as the first light-emitting layer having a first band gap (1.92 [eV]) and an LED light-emitting element 21R as the first light-emitting element, and when viewed from the light emission direction E perpendicular to the light-emitting surface of the LED light-emitting element 21R, the LED display device 1 is arranged so as to overlap at least a part of the LED light-emitting element 21R, and has a first band gap (1.92 [eV] The device includes a second thin film layer 20G as a second layer, which contains an InGaN active layer 62G as a second light-emitting layer having a second band gap (2.38[eV]) larger than the first band gap (1.92[eV]), and a p-type GaP absorption layer 53R as a first light-absorbing layer, which is positioned between the AlGaInP active layer 51R and the InGaN active layer 62G in the light emission direction E, and has a third band gap (2.26[eV]) that is larger than the first band gap (1.92[eV]) and less than or equal to the second band gap (2.38[eV]).

[0135] Furthermore, in the LED display device 1 according to the first embodiment, as described above, if the first layer is the first thin film layer 20R, the second layer is the second thin film layer 20G, and the first light absorption layer is the p-type GaP absorption layer 53R, the third thin film layer 20B, as the third layer, is arranged to overlap at least a portion of the light-emitting elements 21R and 21G when viewed from the light emission direction E, and includes a third light-emitting element 21B having an InGaN active layer 72B as the third light-emitting layer, which has a fourth band gap (2.67 [eV]) that is larger than the second band gap (2.38 [eV]). Furthermore, the p-type InGaN absorption layer 64G, which serves as the second light absorption layer, is positioned between the InGaN active layer 62G and the InGaN active layer 72B in the emission direction E, and has a fifth band gap (2.61 [eV]) that is larger than the second band gap (2.38 [eV]) and less than or equal to the fourth band gap (2.67 [eV]).

[0136] Furthermore, in the LED display device 1 according to the first embodiment, when the first layer is a first thin film layer 20R, the second layer is a third thin film layer 20B, and the first light absorption layer is at least one of a p-type GaP absorption layer 53R or a p-type InGaN absorption layer 64G, the first thin film layer 20R as the first layer has an AlGaInP active layer 51R as the first light-emitting layer having a first band gap (1.92 [eV]) and an LED light-emitting element 21R as the first light-emitting element, and when viewed from the light emission direction E perpendicular to the light-emitting surface of the LED light-emitting element 21R, it is arranged to overlap at least a part of the LED light-emitting element 21R and has a second band gap ( ) that is larger than the first band gap (1.92 [eV]) The device includes a third thin film layer 20B as a second layer, which is a light-emitting element 21B as a second light-emitting element having an InGaN active layer 72B as a second light-emitting layer with a band gap of 2.67 eV, and at least one of the following: a p-type GaP absorption layer 53R as a first light-absorbing layer, which is positioned between the AlGaInP active layer 51R and the InGaN active layer 72B in the light emission direction E and has a third band gap (2.26 eV) that is greater than the first band gap (1.92 eV) and less than or equal to the second band gap (2.67 eV), or a p-type InGaN absorption layer 64G as a first light-absorbing layer, which has a third band gap (2.61 eV).

[0137] Furthermore, in the LED display device 1 according to the first embodiment, when the first layer is a second thin film layer 20G, the second layer is a third thin film layer 20B, and the first light absorption layer is a p-type InGaN absorption layer 64G, the second thin film layer 20G as the first layer has an InGaN active layer 62G as the first light-emitting layer with a first band gap (2.38 [eV]) and an InGaN active layer 62G as the first light-emitting layer with a first band gap (2.38 [eV]), and the second thin film layer 20G as the first layer has an InGaN active layer 62G as the first light-emitting layer with a first band gap (2.38 [eV]), and the second thin film layer 20G as the first layer has an InGaN active layer 62G as the first light-emitting layer with a first band gap (2.38 [eV]). The device includes a third thin film layer 20B as a second layer, which is a second light-emitting element 21B having an InGaN active layer 72B as a second light-emitting layer having a second band gap (2.67 [eV]) that is larger than the first band gap (2.38 [eV]), and a p-type InGaN absorption layer 64G as a first light-absorbing layer, which is positioned between the InGaN active layer 62G and the InGaN active layer 72B in the light emission direction E, and has a third band gap (2.61 [eV]) that is larger than the first band gap (2.38 [eV]) and less than or equal to the second band gap (2.67 [eV]).

[0138] As a result, the LED display device 1 can absorb the light emitted from the active layer in the upper thin film layer 20 and diffused to the lower layer with the first light absorption layer, preventing it from reaching the active layer in the lower thin film layer 20. This prevents the LED display device 1 from generating excitation light by the active layer in the lower thin film layer 20 being excited by the light from the active layer in the upper thin film layer 20.

[0139] [2. Second Embodiment] [2-1. Configuration of LED display device] The LED display device 101 according to the second embodiment (Figure 1) differs from the LED display device 1 according to the first embodiment in that it has an LED display unit 102 instead of the LED display unit 2, but is otherwise configured similarly. The LED display unit 102 (Figures 2 and 3) has a configuration in which a thin film layer group 118 replaces the thin film layer group 18 compared to the LED display unit 2. In addition, the LED display unit 102 has a plurality of pixel units 108 corresponding to each pixel unit 8 of the LED display unit 2, arranged in a grid along the X and Y directions. For the sake of drawing convenience, Figure 10 is a cross-sectional view, but hatching has not been applied.

[0140] [2-2. Composition of Thin Film Layers] [2-2-1. Overall structure of the thin film layer group] The thin film layer group 118 has a second thin film layer 120G instead of the second thin film layer 20G in the thin film layer group 18 according to the first embodiment. As shown in Figure 2(B), the first thin film layer 20R, the second thin film layer 120G, and the third thin film layer 20B constituting the thin film layer group 118 include light-emitting elements 21R, 121G, and 21B that emit red (R), green (G), and blue (B) light, respectively, as well as various wiring materials, etc.

[0141] [2-2-2. Composition of the second thin film layer] As shown in Figure 9, which assigns the same reference numerals to the components corresponding to Figure 4, and in Figure 10, which assigns the same reference numerals to the components corresponding to Figure 6, the second thin film layer 120G differs from the second thin film layer 20G according to the first embodiment in that it has an anode layer 133G instead of an anode layer 33G, an emissive layer 132G instead of an emissive layer 32G, a cathode layer 31G, a cathode lead wiring 43G, an insulating layer 37GG, and a lower electrode 93G instead of a cathode electrode pad 42GG, and also has an additional metal layer 91G and a cathode layer 92G, but is otherwise configured similarly.

[0142] The anode layer 133G, light-emitting layer 132G, metal layer 91G, and cathode layer 92G are formed in a substantially square shape when viewed from the Z direction and are located approximately in the center of the pixel portion 108 in the X and Y directions. Furthermore, when viewed from the Z direction, the anode layer 133G, light-emitting layer 132G, metal layer 91G, and cathode layer 92G have a larger area than the anode layer 33G in the first embodiment (Figures 4 and 6) and the circular portion of the InGaN active layer 62G, p-type GaN layer 63G, and p-type InGaN absorption layer 64G of the light-emitting layer 32G when viewed from the Z direction.

[0143] Therefore, the anode layer 133G, light-emitting layer 132G, metal layer 91G, and cathode layer 92G have a larger area when viewed from the Z direction than the light-emitting layer 32R, anode layer 33R, and cathode layer 31R in the first thin film layer 20R (Figures 5 and 10), the anode layer 33B in the third thin film layer 20B (Figures 3 and 10), and the circular portion of the InGaN active layer 72B and p-type GaN layer 73B in the light-emitting layer 32B.

[0144] The light-emitting layer 132G is constructed by sequentially stacking an n-type GaN layer 161G, an InGaN active layer 162G, a p-type GaN layer 163G, and a p-type InGaN absorption layer 164G, with the n-type GaN layer 161G, InGaN active layer 162G, p-type GaN layer 163G, and p-type InGaN absorption layer 164G, for example, the same materials as the AlN buffer layer 60G, n-type GaN layer 61G, InGaN active layer 62G, p-type GaN layer 63G, and p-type InGaN absorption layer 64G in the light-emitting layer 32G (Figure 6), respectively.

[0145] The metal layer 91G is laminated on the +Z direction side of the underlying insulating layer 25G and is composed of a transparent conductive film made of a material such as ITO, or a single or multiple layered structure made of a metal such as Au, Al, Cu, Pt, or Ti, or an alloy thereof. This metal layer 91G is formed between the cathode layer 92G and the lower electrode 93G, electrically connecting the cathode layer 92G and the lower electrode 93G. The cathode layer 92G is made of Au, Al, Cu, Pt, or Ti, is conductive, and is electrically connected to the lower electrode 93G via the metal layer 91G.

[0146] The lower electrode 93G is part of the vertical wiring 23G and is constructed as a single-layer or multi-layer laminated structure of a metal such as Au, Al, Cu, Pt, or Ti, or an alloy thereof, and is electrically conductive. The lower electrode 93G is formed to fill the opening 38GG formed in the underlying insulating layer 25G, and its upper and lower surfaces are the same plane as the upper and lower surfaces of the underlying insulating layer 25B, respectively. The lower electrode 93G is electrically connected by contacting the upper surface of the cathode pillar 46GR in the first thin film layer 20R with its lower surface, and by contacting the metal layer 91G with its upper surface.

[0147] [2-3. Method for manufacturing the LED display unit] The method for manufacturing the LED display unit 102 in the LED display device 101 is substantially the same as the method for manufacturing the LED display unit 2 in the LED display device 1 according to the first embodiment, so a detailed explanation is omitted.

[0148] [2-4. Effects, etc.] In the LED display device 1 according to the first embodiment, the InGaN active layer 62G of the light-emitting layer 32G in the second thin film layer 20G is made of InGaN (indium gallium nitride), similar to the InGaN active layer 72B of the light-emitting layer 32B in the third thin film layer 20B. Here, in a stacked light-emitting display device in which multiple color light-emitting elements are stacked, the ratio of the amount of light emitted from the surface (light-emitting surface) of the pixels to the supplied power is defined as the light extraction efficiency. In the LED display device 1, the second thin film layer 20G is positioned on the opposite side of the light emission direction E from the third thin film layer 20B. As a result, in the LED display device 1, the light extraction efficiency of the second thin film layer 20G (green) is lower than that of the third thin film layer 20B (blue).

[0149] In contrast, in the LED display device 101, the light-emitting layer 132G of the second thin film layer 20G is configured to have a larger area when viewed from the Z direction than the light-emitting layer 32B of the third thin film layer 20B (Figure 3). As a result, in the LED display device 101, the amount of light emitted from the second thin film layer 120G can be greater than the amount of light emitted from the third thin film layer 20B. This prevents the light extraction efficiency of the second thin film layer 20G (green) from becoming lower than that of the third thin film layer 20B (blue), even if the second thin film layer 120G is positioned on the opposite side of the light emission direction E from the third thin film layer 20B.

[0150] Furthermore, the LED display device 101 can more reliably absorb the blue light emitted from the InGaN active layer 72B and diffused in the -Z direction by the p-type InGaN absorption layer 164G, which has a larger area than the InGaN active layer 72B.

[0151] Furthermore, the LED display device 101 according to the second embodiment can obtain the same effects and advantages as the LED display device 1 according to the first embodiment in other respects as well.

[0152] [3. Third Embodiment] [3-1. Configuration of LED display device] The LED display device 201 according to the third embodiment (Figure 1) differs from the LED display device 1 according to the first embodiment in that it has an LED display unit 202 instead of the LED display unit 2, but is otherwise configured similarly. The LED display unit 202 (Figures 2 and 3) has a configuration in which a thin film layer group 218 replaces the thin film layer group 18 compared to the LED display unit 2. In addition, the LED display unit 202 has a plurality of pixel units 208 corresponding to each pixel unit 8 of the LED display unit 2, arranged in a grid along the X and Y directions. For the sake of drawing convenience, Figure 13 is a cross-sectional view, but hatching has not been applied.

[0153] [3-2. Composition of Thin Film Layers] [3-2-1. Overall structure of the thin film layer group] The thin film layer group 218 has a second thin film layer 220G in place of the second thin film layer 20G in the thin film layer group 18 according to the first embodiment, and a third thin film layer 220B in place of the third thin film layer 20B. As shown in Figure 2(B), the first thin film layer 20R, the second thin film layer 220G, and the third thin film layer 220B constituting the thin film layer group 218 include light-emitting elements 21R, 221G, and 221B that emit red (R), green (G), and blue (B) light, respectively, as well as various wiring materials, etc.

[0154] [3-2-2. Composition of the second thin film layer] As shown in Figure 12, which assigns the same reference numerals to the components corresponding to Figure 4, and in Figure 13, which assigns the same reference numerals to the components corresponding to Figure 6, the second thin film layer 220G differs from the second thin film layer 20G according to the first embodiment in that it has an anode layer 233G instead of an anode layer 33G and an emissive layer 232G instead of an emissive layer 32G, but is otherwise configured similarly.

[0155] The anode layer 233G and the AlGaInP active layer 262G and p-type AlInP layer 263G of the light-emitting layer 232G are formed in a circular shape when viewed from the Z direction and are located approximately in the center of the pixel portion 208 in the X and Y directions. The AlAs buffer layer 260G, AlGaInP absorption layer 94G and n-type AlInP layer 261G of the light-emitting layer 232G have a shape that combines a circular portion that is slightly larger than the anode layer 233G and the AlGaInP active layer 262G and p-type AlInP layer 263G of the light-emitting layer 232G, with a roughly square portion that protrudes from the circular portion in the +X direction, when viewed from the Z direction. The center of the circular portion is located approximately in the center of the pixel portion 208 in the X and Y directions. For this reason, when viewed from the Z direction, the AlGaInP absorption layer 94G has a larger area than the AlGaInP active layer 262G.

[0156] [3-2-3. Composition of the third thin film layer] As shown in Figure 11, which assigns the same reference numerals to the components corresponding to Figure 3, and in Figure 13, which assigns the same reference numerals to the components corresponding to Figure 6, the third thin film layer 220B differs from the third thin film layer 20B according to the first embodiment in that it has an anode layer 233B instead of an anode layer 33B and an emissive layer 232B instead of an emissive layer 32B, but is otherwise configured similarly.

[0157] The anode layer 233B and the InGaN active layer 272B and p-type GaN layer 273B of the light-emitting layer 232B are formed in a circular shape when viewed from the Z direction and are located approximately in the center of the pixel portion 208 in the X and Y directions. The AlN buffer layer 70B, InGaN absorption layer 96B and n-type GaN layer 271B of the light-emitting layer 232B have a shape when viewed from the Z direction that combines a circular portion that is slightly larger than the anode layer 233B and the InGaN active layer 272B and p-type GaN layer 273B of the light-emitting layer 232B with a roughly rectangular portion that protrudes from the circular portion in the -X direction, with the center of the circular portion located approximately in the center of the pixel portion 8 in the X and Y directions. For this reason, when viewed from the Z direction, the InGaN absorption layer 96B has a larger area than the InGaN active layer 272B.

[0158] [3-3. Configuration and Bandgap of Light-Emitting Devices] [3-3-1. Configuration and bandgap of the third thin film layer] The light-emitting layer 232B is constructed by sequentially stacking the AlN buffer layer 70B, InGaN absorption layer 96B, n-type GaN layer 271B, InGaN active layer 272B, and p-type GaN layer 273B in an overlapping manner from the -Z direction to the +Z direction.

[0159] InGaN active layer 272B has a composition of In0.1Ga0.9N to In0.2Ga0.8N, a band gap of 2.67 to 3.06 [eV], and a peak emission wavelength of 405 to 465 [nm]. In this embodiment, InGaN active layer 72B has a composition of In0.22Ga0.78N, a band gap of 2.67 [eV], and a peak emission wavelength of 465 [nm].

[0160] The InGaN absorption layer 96B is a light absorption layer that absorbs light emitted from the InGaN active layer 272B located on the +Z side and diffused in the -Z direction. This InGaN absorption layer 96B has a composition of In0.2Ga0.8N to In0.45Ga0.55N and a band gap of 2.38 to 2.67 [eV], and almost completely absorbs blue light emission. In this embodiment, the composition of the InGaN absorption layer 96B is In0.45Ga0.55N and the band gap is 2.38 [eV]. Alternatively, the composition of the InGaN absorption layer 96B may be the same as that of the InGaN active layer 272B.

[0161] The band gap of the InGaN absorption layer 96B (2.38 eV) is larger than the band gap of the AlGaInP active layer 262G of the second thin film layer 220G (2.2 eV) (described later) and the band gap of the AlGaInP active layer 51R of the first thin film layer 20R (1.92 eV). Therefore, the InGaN absorption layer 96B allows the green light emitted from the AlGaInP active layer 262G of the second thin film layer 220G and the red light emitted from the AlGaInP active layer 51R of the first thin film layer 20R to pass through in the +Z direction without being absorbed.

[0162] On the other hand, the band gap of the InGaN absorption layer 96B (2.38 eV) is less than or equal to the band gap of the InGaN active layer 272B (2.67 eV). Therefore, the InGaN absorption layer 96B absorbs the blue light emitted from the InGaN active layer 272B.

[0163] The composition of the InGaN absorption layer 96B is just an example, and can be adjusted within a band gap range that is larger than that of the AlGaInP active layer 262G of the second thin film layer 220G (i.e., the AlGaInP active layer 51R of the first thin film layer 20R) and smaller than or equal to that of the InGaN active layer 272B. Furthermore, the closer the band gap of the InGaN absorption layer 96B is to that of the InGaN active layer 272B, the closer the excitation light of the InGaN absorption layer 96B is to that of the InGaN active layer 272B will be to that of the blue light emitted from the InGaN active layer 272B. For this reason, the LED display device 201 can enhance its ability to prevent the mixing of green light with the blue light emitted from the InGaN active layer 272B by making the band gap of the InGaN absorption layer 96B closer to that of the InGaN active layer 272B. For this reason, it is preferable that the band gap of the InGaN absorption layer 96B is closer to that of the InGaN active layer 272B than to that of the AlGaInP active layer 262G of the second thin film layer 220G.

[0164] Therefore, the effect of preventing color mixing of blue light emission can be maximized when the InGaN absorption layer 96B has the same band gap as the InGaN active layer 272B. However, even if the band gap of the InGaN absorption layer 96B is set to be the same as that of the InGaN active layer 272B, if the band gap of the InGaN absorption layer 96B becomes larger than that of the InGaN active layer 272B due to manufacturing errors or the like, the blue light emitted from the InGaN active layer 272B will pass through the InGaN absorption layer 96B without being absorbed. For this reason, taking such manufacturing errors into consideration, it is preferable to set the band gap of the InGaN absorption layer 96B to be as close as possible to that of the InGaN active layer 272B, and to be less than or equal to that of the InGaN active layer 272B.

[0165] [3-3-2. Configuration and bandgap of the second thin film layer's light-emitting element] The light-emitting layer 232G is constructed by sequentially stacking the AlAs buffer layer 260G, AlGaInP absorption layer 94G, n-type AlInP layer 261G, AlGaInP active layer 262G, and p-type AlInP layer 263G in an overlapping manner from the -Z direction to the +Z direction.

[0166] The AlGaInP active layer 262G has a composition of (Al0.0Ga1.0)0.5In0.5P to (Al0.7Ga0.3)0.5In0.5P, a band gap of 1.91 to 2.23 [eV], and a peak emission wavelength of 556 to 650 [nm]. In this embodiment, the AlGaInP active layer 262G has a composition of (Al0.45Ga0.55)0.5In0.5P, a band gap of 2.2 [eV], and a peak emission wavelength of 560 [nm].

[0167] The AlGaInP absorption layer 94G is a light absorption layer that absorbs light emitted from the AlGaInP active layer 262G located on the +Z side and diffused in the -Z direction, and light emitted from the InGaN active layer 272B and diffused in the -Z direction. This AlGaInP absorption layer 94G has a composition of (Al0.30Ga0.70)0.5In0.5P~(Al0.45Ga0.55)0.5In0.5P and a band gap of 2.1~2.2 [eV], and almost completely absorbs blue and green light emission. In this embodiment, the composition of the AlGaInP absorption layer 94G is (Al0.30Ga0.70)0.5In0.5P and a band gap of 2.1 [eV]. Alternatively, the composition of the AlGaInP absorption layer 94G may be the same as that of the AlGaInP active layer 262G.

[0168] The band gap of the AlGaInP absorption layer 94G (2.2 eV) is larger than the band gap of the AlGaInP active layer 51R of the first thin film layer 20R (1.92 eV). Therefore, the AlGaInP absorption layer 94G does not absorb the red light emitted from the AlGaInP active layer 51R, but allows it to pass through in the +Z direction.

[0169] On the other hand, the band gap of the AlGaInP absorption layer 94G (2.1-2.2 eV) is less than or equal to the band gap of the AlGaInP active layer 262G (2.2 eV). Therefore, the AlGaInP absorption layer 94G absorbs the blue light emitted from the AlGaInP active layer 262G.

[0170] The composition of the AlGaInP absorption layer 94G is just an example, and can be adjusted within a band gap range that is larger than that of the AlGaInP active layer 51R of the first thin film layer 20R and less than or equal to the AlGaInP active layer 262G (i.e., less than or equal to the InGaN active layer 272B of the third thin film layer 220B). Furthermore, the closer the band gap of the AlGaInP absorption layer 94G is to that of the AlGaInP active layer 262G, the closer the excitation light of the AlGaInP absorption layer 94G is to that of the AlGaInP active layer 262G will be to that of the green emission emitted from the AlGaInP active layer 262G. For this reason, the LED display device 201 can enhance its ability to prevent the mixing of red emission with the green emission emitted from the AlGaInP active layer 262G by making the band gap of the AlGaInP absorption layer 94G closer to that of the AlGaInP active layer 262G. Therefore, it is preferable that the band gap of the AlGaInP absorption layer 94G is closer to the AlGaInP active layer 262G than to the AlGaInP active layer 51R of the first thin film layer 20R.

[0171] Therefore, the effect of preventing mixing of green emission can be maximized when the AlGaInP absorption layer 94G has the same band gap as the AlGaInP active layer 262G. However, even if the band gap of the AlGaInP absorption layer 94G is set to be the same as that of the AlGaInP active layer 262G, if the band gap of the AlGaInP absorption layer 94G becomes larger than that of the AlGaInP active layer 262G due to manufacturing errors, etc., the green emission emitted from the AlGaInP active layer 262G will pass through the AlGaInP absorption layer 94G without being absorbed. For this reason, taking such manufacturing errors into consideration, it is preferable to set the band gap of the AlGaInP absorption layer 94G to be as close as possible to that of the AlGaInP active layer 262G, and to be less than or equal to that of the AlGaInP active layer 262G.

[0172] [3-4. Method for manufacturing the LED display unit] The method for manufacturing the LED display unit 202 in the LED display device 201 is substantially the same as the method for manufacturing the LED display unit 2 in the LED display device 1 according to the first embodiment, so a detailed explanation is omitted.

[0173] [3-5. Effects, etc.] In the above configuration, the LED display device 201 has an InGaN absorption layer 96B that absorbs blue light emitted from the InGaN active layer 272B of the third thin film layer 220B, which is the same thin film layer 20 as the InGaN active layer 272B, and is positioned on the -Z side of the third thin film layer 220B than the InGaN active layer 272B.

[0174] Similarly, in the LED display device 201, the AlGaInP absorption layer 94G, which absorbs the green light emitted from the AlGaInP active layer 262G of the second thin film layer 220G, is positioned on the -Z side of the second thin film layer 220G, which is the same thin film layer 20 as the AlGaInP active layer 262G.

[0175] In other words, the LED display device 201 is configured to place a light-absorbing layer that absorbs light emitted from the active layer in the same thin film layer 20 as the active layer. Therefore, the LED display device 201 can choose whether or not to form a light-absorbing layer that absorbs light directed from the active layer towards the lower layer within the thin film layer 20 in which the active layer is located.

[0176] Furthermore, the LED display device 201 is configured such that the InGaN absorption layer 96B in the third thin film layer 220B has a larger area when viewed from the Z direction than the InGaN active layer 272B. As a result, the LED display device 201 can more reliably absorb the blue light emitted from the InGaN active layer 272B and diffused in the -Z direction by the InGaN absorption layer 96B.

[0177] Similarly, in the LED display device 201, the AlGaInP absorption layer 94G in the second thin film layer 220G is configured to have a larger area when viewed from the Z direction than the AlGaInP active layer 262G. As a result, the LED display device 201 can more reliably absorb the green light emitted from the AlGaInP active layer 262G and diffused in the -Z direction by the AlGaInP absorption layer 94G.

[0178] In other words, the LED display device 201 places a light-absorbing layer, which absorbs light emitted from the active layer, on the same thin film layer 20 as the active layer, and configures the light-absorbing layer to have a larger area than the active layer. As a result, the LED display device 201 can more reliably absorb the light emitted from the active layer and diffused in the -Z direction by the light-absorbing layer.

[0179] Furthermore, since the LED display device 201 places the light-absorbing layer in the same thin film layer 20 as the active layer, the area of ​​the light-absorbing layer can be easily manufactured to be larger than the area of ​​the active layer during the manufacturing process, compared to the case where the light-absorbing layer is placed in the thin film layer 20 below the active layer.

[0180] Furthermore, the LED display device 201 according to the third embodiment can obtain the same effects and advantages as the LED display device 1 according to the first embodiment in other respects as well.

[0181] According to the above configuration, the LED display device 201 according to the third embodiment comprises, when the first layer is a first thin film layer 20R, the second layer is a second thin film layer 220G, and the first light absorption layer is an AlGaInP absorption layer 94G, the first thin film layer 20R as the first layer has an AlGaInP active layer 51R as the first light-emitting layer having a first band gap (1.92 [eV]) and an AlGaInP active layer 51R as the first light-emitting layer having a first band gap (1.92 [eV]), and the first thin film layer 20R as the first layer has). The device includes a second thin film layer 220G as a second layer, which contains an AlGaInP active layer 262G as a second light-emitting layer having a second band gap (2.2[eV]) larger than the first band gap (1.92[eV]), and an AlGaInP absorption layer 94G as a first light-absorbing layer, which is positioned between the AlGaInP active layer 51R and the AlGaInP active layer 262G in the emission direction E, and has a third band gap (2.1[eV]) that is larger than the first band gap (1.92[eV]) and less than or equal to the second band gap (2.2[eV]).

[0182] Furthermore, in the LED display device 201 according to the third embodiment, as described above, if the first layer is the first thin film layer 20R, the second layer is the second thin film layer 220G, and the first light absorption layer is the AlGaInP absorption layer 94G, the third thin film layer 220B, as the third layer, is arranged to overlap at least a portion of the light-emitting elements 21R and 221G when viewed from the light emission direction E, and includes a third light-emitting element 221B having an InGaN active layer 272B as the third light-emitting layer with a fourth band gap (2.67 [eV]) that is larger than the second band gap (2.2 [eV]). Furthermore, the InGaN absorption layer 96B, which serves as the second light absorption layer, is positioned between the AlGaInP active layer 262G and the InGaN active layer 272B in the emission direction E, and has a fifth band gap (2.38 [eV]) that is larger than the second band gap (2.2 [eV]) and less than or equal to the fourth band gap (2.67 [eV]).

[0183] Furthermore, in the LED display device 201 according to the third embodiment, when the first layer is a first thin film layer 20R, the second layer is a third thin film layer 220B, and the first light absorption layer is at least one of AlGaInP absorption layer 94G or InGaN absorption layer 96B, the first thin film layer 20R as the first layer has an AlGaInP active layer 51R as the first light-emitting layer having a first band gap (1.92 [eV]) and an LED light-emitting element 21R as the first light-emitting element, and when viewed from the light emission direction E perpendicular to the light-emitting surface of the LED light-emitting element 21R, it is arranged to overlap at least a part of the LED light-emitting element 21R and has a second band gap ( ) that is larger than the first band gap (1.92 [eV]) The device includes a third thin film layer 220B as a second layer, which includes an light-emitting element 221B as a second light-emitting element having an InGaN active layer 272B as a second light-emitting layer with a band gap of 2.67 eV, and at least one of the following: an AlGaInP absorption layer 94G as a first light-absorbing layer with a third band gap (2.1 eV) that is larger than the first band gap (1.92 eV) and less than or equal to the second band gap (2.67 eV), or an InGaN absorption layer 96B as a first light-absorbing layer with a third band gap (2.38 eV).

[0184] Furthermore, in the LED display device 201 according to the third embodiment, when the first layer is the second thin film layer 220G, the second layer is the third thin film layer 220B, and the first light absorption layer is the InGaN absorption layer 96B, the second thin film layer 220G as the first layer has an AlGaInP active layer 262G as the first light-emitting layer having a first band gap (2.2 [eV]) and an light-emitting element 221G as the first light-emitting element, and when viewed from the light emission direction E perpendicular to the light-emitting surface of the light-emitting element 221G, the second thin film layer 220G as the first layer has an AlGaInP active layer 262G as the first light-emitting layer having a first band gap (2.2 [eV]), and the second thin film layer 220G as the first layer has an AlGaInP active layer 262G as the first light-emitting element having a first band gap (2.2 [eV] The device includes a third thin film layer 220B as a second layer, which contains an InGaN active layer 272B as a second light-emitting layer having a second band gap (2.67 eV) larger than the first band gap (2.2 eV), and an InGaN absorption layer 96B as a first light-absorbing layer, which is positioned between the AlGaInP active layer 262G and the InGaN active layer 272B in the light emission direction E, and has a third band gap (2.38 eV) that is larger than the first band gap (2.2 eV) and less than or equal to the second band gap (2.67 eV).

[0185] [4. Other Embodiments] In the first embodiment described above, the LED display device 1 is configured such that the p-type InGaN absorption layer 64G that absorbs blue light emission in the second thin film layer 20G is made of InGaN (indium gallium nitride), and the p-type GaP absorption layer 53R that absorbs green light emission in the first thin film layer 20R is made of GaP (gallium phosphide). The present invention is not limited to this, and the LED display device 1 may be configured with light absorption layers that absorb blue light emission and light absorption layers that absorb green light emission using various other materials. The same applies to the second embodiment.

[0186] Furthermore, in the third embodiment described above, the LED display device 201 is configured such that the InGaN absorption layer 96B that absorbs blue light emission in the third thin film layer 220B is made of InGaN (indium gallium nitride), and the AlGaInP absorption layer 94G that absorbs green light emission in the second thin film layer 220G is made of AlGaInP (aluminum gallium indium phosphate). The present invention is not limited to this, and the LED display device 1 may be configured with light absorption layers that absorb blue light emission and light absorption layers that absorb green light emission using various other materials.

[0187] Furthermore, in the first embodiment described above, the LED display device 1 was described in a case where the p-type InGaN absorption layer 64G and the InGaN active layer 62G in the second thin film layer 20G are made of the same material but with different compositions. The present invention is not limited to this, and the LED display device 1 may also be made of different materials for the p-type InGaN absorption layer 64G and the InGaN active layer 62G. However, when the p-type InGaN absorption layer 64G and the InGaN active layer 62G are made of the same material, it becomes possible to form a layer with good crystallinity when forming the thin film layer 20 with a film deposition apparatus such as MOCVD (Metal Organic Chemical Vapor Deposition). The same applies to the p-type InGaN absorption layer 164G and InGaN active layer 162G in the second thin film layer 120G according to the second embodiment, the InGaN absorption layer 96B and InGaN active layer 272B in the third thin film layer 220B according to the third embodiment, and the AlGaInP absorption layer 94G and AlGaInP active layer 262G in the second thin film layer 220G.

[0188] Furthermore, in the first embodiment described above, the LED display device 1 was described in which the p-type GaP absorption layer 53R and the AlGaInP active layer 51R in the first thin film layer 20R are made of different materials. The present invention is not limited to this, and the LED display device 1 may also be made of the same material but with different compositions for the p-type GaP absorption layer 53R and the AlGaInP active layer 51R. In that case, when forming the thin film layer 20 with a film deposition apparatus such as MOCVD, it becomes possible to form a layer with good crystallinity. The same applies to the p-type GaP absorption layer 53R and the AlGaInP active layer 51R in the first thin film layer 20R according to the second embodiment and the p-type GaP absorption layer 53R and the AlGaInP active layer 51R in the first thin film layer 20R according to the third embodiment.

[0189] Furthermore, in the first embodiment described above, the LED display device 1 was described in a case where the AlGaInP active layer 51R, which is the red-emitting active layer in the first thin film layer 20R, is made of AlGaInP (aluminum gallium indium phosphate). The present invention is not limited to this, and the LED display device 1 may also have the red-emitting active layer in the first thin film layer 20R made of various other materials, such as InGaN, GaP, or GaAsP. Similarly, the active layers in the second thin film layer 20G and the third thin film layer 20B may also be made of various other materials. The same applies to the second and third embodiments.

[0190] Furthermore, the LED display device 1 according to the first embodiment described above may be provided with a third thin film layer 220B according to the third embodiment instead of the third thin film layer 20B. In that case, the LED display device 1 can absorb blue light emission with the InGaN absorption layer 96B of the third thin film layer 220B, so the p-type InGaN absorption layer 64G of the second thin film layer 20G does not need to be provided.

[0191] Furthermore, in the third embodiment described above, the LED display device 201 is described in the case where a p-type GaP absorption layer 53R is provided on the first thin film layer 20R (Figure 13). The present invention is not limited to this, and since the LED display device 201 can absorb green light emission with the AlGaInP absorption layer 94G of the second thin film layer 220G, the p-type GaP absorption layer 53R of the first thin film layer 20R does not need to be provided.

[0192] Furthermore, in the first embodiment described above, the LED display device 1 is described in a case where the InGaN active layer 72B of the third thin film layer 20B, the InGaN active layer 62G of the second thin film layer 20G, and the AlGaInP active layer 51R of the first thin film layer 20R are configured as single layers. The present invention is not limited to this, and the LED display device 1 may also be configured with at least one of the InGaN active layer 72B, InGaN active layer 62G, and AlGaInP active layer 51R as a multi-quantum well (MQW). The same applies to the second and third embodiments.

[0193] Furthermore, in the first embodiment described above, the LED display device 1 was described in the case where the common electrode is the anode. The present invention is not limited to this, and the LED display device 1 may also use the common electrode as the cathode. The same applies to the second and third embodiments.

[0194] Furthermore, in the first embodiment described above, the manufacturing apparatus 60 describes the case in which each layer is epitaxially grown on the upper side of a silicon substrate 80G (crystal orientation

[0111] ) in the method for manufacturing the second thin film layer 20G (Figure 7(A)). The present invention is not limited to this, and the manufacturing apparatus 60 may also epitaxially grow each layer on the upper side of a substrate made of various other materials, such as a sapphire substrate. The same applies to the method for manufacturing the first thin film layer 20R and the third thin film layer 20B. The same also applies to the second and third embodiments.

[0195] Furthermore, in the first embodiment described above, the LED display device 1 was described in a case where the light-emitting elements 21R, 21G, and 21B were stacked so that their centers coincided when viewed from the Z direction. The present invention is not limited to this, and the LED display device 1 can be provided by stacking the light-emitting elements 21R, 21G, and 21B so that at least a portion of them overlap when viewed from the Z direction. The same applies to the second and third embodiments.

[0196] Furthermore, in the first embodiment described above, the LED display device 1 is provided with three thin film layers 20, a first thin film layer 20R, a second thin film layer 20G, and a third thin film layer 20B, in the LED display unit 2. The present invention is not limited to this, and the LED display device 1 may also bond a fourth thin film layer or a fifth thin film layer to the third thin film layer 20B to expand the light output and color gamut. Alternatively, the LED display device 1 may combine only two of the three thin film layers 20, the first thin film layer 20R, the second thin film layer 20G, and the third thin film layer 20B, to create a two-color display. In other words, the LED display device 1 may also provide the LED display unit 2 with any number of thin film layers 20 other than the three thin film layers 20, such as two or four or more layers. The same applies to the second and third embodiments.

[0197] Furthermore, the first embodiment described above described an application of the present invention to a direct-viewing type LED display device 1. The present invention is not limited to this, and may also be applied to display devices used as projectors or light sources, for example. The same applies to the second and third embodiments.

[0198] Furthermore, in the first embodiment described above, the LED display device 1 was described in a case where the circuit board 10 was made of a CMOS circuit board. The present invention is not limited to this, and the LED display device 1 may also be made of a thin-film transistor (TFT) circuit board. The same applies to the second and third embodiments.

[0199] Furthermore, the first embodiment described above describes the case in which the LED display device 1 uses light-emitting elements 21 (light-emitting elements 21R, 21G, and 21B) as semiconductor elements. The present invention is not limited to this, and the LED display device 1 may use various other semiconductor elements such as photodiodes and transistors. The same applies to the second and third embodiments.

[0200] Furthermore, the present invention is not limited to the embodiments described above and other embodiments. That is, the scope of the present invention also extends to embodiments obtained by arbitrarily combining some or all of the embodiments described above and other embodiments. In addition, the scope of the present invention also extends to embodiments obtained by extracting a part of the configuration described in any embodiment from the embodiments described above and other embodiments and substituting or adapting it for a part of the configuration of any embodiment from the embodiments described above and other embodiments, or by adding a part of the extracted configuration to any embodiment.

[0201] Furthermore, in the first embodiment described above, we have described the case in which the LED display device 1 as a light-emitting device is configured by a first thin film layer 20R as a first layer, a second thin film layer 20G as a second layer, and a p-type GaP absorption layer 53R as a first light-absorbing layer, or by a first thin film layer 20R as a first layer, a third thin film layer 20B as a second layer, and at least one of the p-type GaP absorption layer 53R or p-type InGaN absorption layer 64G as a first light-absorbing layer, or by a second thin film layer 20G as a first layer, a third thin film layer 20B as a second layer, and a p-type InGaN absorption layer 64G as a first light-absorbing layer.

[0202] Furthermore, in the second embodiment described above, the case in which the LED display device 101 as a light-emitting device is configured by a first thin film layer 20R as a first layer, a second thin film layer 120G as a second layer, and a p-type GaP absorption layer 53R as a first light-absorbing layer, or by a first thin film layer 20R as a first layer, a third thin film layer 20B as a second layer, and at least one of the p-type GaP absorption layer 53R or p-type InGaN absorption layer 164G as a first light-absorbing layer, or by a second thin film layer 120G as a first layer, a third thin film layer 20B as a second layer, and a p-type InGaN absorption layer 164G as a first light-absorbing layer, has been described.

[0203] Furthermore, in the third embodiment described above, the case in which the LED display device 201 as a light-emitting device is configured by a first thin film layer 20R as a first layer, a second thin film layer 220G as a second layer, and an AlGaInP absorption layer 94G as a first light-absorbing layer, or by a first thin film layer 20R as a first layer, a third thin film layer 220B as a second layer, and at least one of the AlGaInP absorption layer 94G or InGaN absorption layer 96B as a first light-absorbing layer, or by a second thin film layer 220G as a first layer, a third thin film layer 220B as a second layer, and an InGaN absorption layer 96B as a first light-absorbing layer was described.

[0204] The present invention is not limited to this, and the light-emitting device may be configured with a first layer, a second layer, and a first light-absorbing layer having various other configurations. [Industrial applicability]

[0205] The present invention can be used, for example, in an LED display device in which multiple LEDs are arranged in a planar configuration. [Explanation of Symbols]

[0206] 1, 101, 201... LED display device, 2, 102, 202... LED display display section, 2A... Display area, 8, 108, 208... Pixel section, 8S... Light-emitting surface, 10... Circuit board, 10S... Substrate surface, 11... Substrate section, 12B, 12G, 12R... Cathode substrate pad, 13... Anode substrate pad, 18, 118, 218... Thin film layer group, 19... Common wiring layer, 20... Thin film layer, 20B, 220B... Third thin film layer, 20G, 120G, 220G... Second thin film layer, 20R... First thin film layer, 21, 21B, 21G, 21R, 121G ,221G, 221B...light-emitting element, 22...light-emitting part, 23, 23B, 23G, 23R, 23A...vertical wiring, 25B, 25G, 25R...underlying insulating layer, 26B, 26G, 26R...interlayer insulating layer, 31B, 31G, 31R...cathode layer, 32B, 32G, 32R, 132G...light-emitting layer, 33B, 33G, 33R, 133G, 233B, 233G...anode layer, 37R, 37AG, 37GG, 37AB, 37BB...insulating layer, 38BR, 38GR, 38RR, 38AR, 38BG, 38GG, 38AG, 38BB, 38AB...opening, 42RR, 42GR, 42BR, 42BG, 42GG... Cathode electrode pads, 42AR, 42AG, 42AB... Anode electrode pads, 43B, 43G, 43R... Cathode lead wiring, 45R, 45G, 45B... Anode pillars, 46BR, 46GR, 46BG... Cathode pillars, 50R... n-type AlInP layer, 51R... AlGaInP active layer, 52R... p-type AlInP layer, 53R... p-type GaP absorption layer, 60G... AlN buffer layer, 61G, 161G... n-type GaN layer, 62G, 162G... InGaN active layer, 63G, 163G... p-type GaN layer, 64G, 164G...p-type InGaN absorption layer, 70B...AlN buffer layer, 71B, 271B...n-type GaN layer, 72B, 272B...InGaN active layer, 73B, 273B...p-type GaN layer, 80G...silicon substrate, 81G...sacrificial layer portion, 82G...resist support layer, 83G...green LED substrate, 84G...LED growth substrate, 85G...sacrificial layer, 86R...GaAs substrate, 87R...AlAs sacrificial layer, 88R...resist support layer, 89R...red LED substrate, 90R...sacrificial layer, 91G...metal layer, 92G...cathode layer, 93G...bottom electrode,260G...AlAs buffer layer, 94G...AlGaInP absorption layer, 261G...n-type AlInP layer, 262G...AlGaInP active layer, 263G...p-type AlInP layer, 96B...InGaN absorption layer.

Claims

1. A first layer having a first light-emitting element having a first light-emitting layer which has a first band gap, A second layer includes a second light-emitting element which, when viewed from a light-emitting direction perpendicular to the light-emitting surface of the first light-emitting element, is arranged to overlap at least a portion of the first light-emitting element and has a second light-emitting layer having a second band gap larger than the first band gap, A first light-absorbing layer is disposed between the first light-emitting layer and the second light-emitting layer in the aforementioned light-emitting direction, and has a third band gap that is larger than the first band gap and less than or equal to the second band gap. A light-emitting device having the following features.

2. The first light-absorbing layer is formed on the first light-emitting element. The light-emitting device according to claim 1.

3. The magnitude of the third band gap is closer to the magnitude of the second band gap than the magnitude of the first band gap. The light-emitting device according to claim 1.

4. The magnitude of the third band gap is the same as the magnitude of the second band gap. The light-emitting device according to claim 3.

5. The first light-emitting element and the second light-emitting element are The light is emitted in the light emission direction from the first light-emitting element toward the second light-emitting element, The first light-absorbing layer is The light emitted from the second light-emitting element and directed toward the first light-emitting element is absorbed. The light-emitting device according to claim 1.

6. A third layer includes a third light-emitting element which, when viewed from the aforementioned light-emitting direction, is arranged to overlap at least a portion of the first light-emitting element and the second light-emitting element, and has a third light-emitting layer having a fourth band gap larger than the second band gap, A second light-absorbing layer is disposed between the second light-emitting layer and the third light-emitting layer in the aforementioned light-emitting direction, and has a fifth band gap that is larger than the second band gap and less than or equal to the fourth band gap. The light-emitting device according to claim 1, further comprising:

7. The first light-absorbing layer is formed on the second light-emitting element. The light-emitting device according to claim 1.

8. The wavelength of light emitted from the first light-emitting element is longer than the wavelength of light emitted from the second light-emitting element. A light-emitting device according to any one of claims 1 to 7.

Images