Light-emitting device and image display device

Abstract

A light emitting device according to an embodiment of the present disclosure includes: a driving circuit board; and an element substrate having a first surface as a light emitting surface and a second surface opposite to the first surface and facing the driving circuit board. An element substrate including a pixel array unit in which a plurality of pixels are arranged in an array; and is configured such that two or more light-emitting elements having a mesa structure are provided to each pixel.

Description

Technical Field

[0001] The present disclosure relates to a light emitting device and an image display device having the same. Background Art

[0002] For example, Patent Document 1 discloses a micro LED formed by covering a crystal growth substrate with a mask layer having a plurality of openings and selectively growing one or more semiconductor rods having a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type by metal organic chemical vapor deposition (MOCVD).

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. WO 2020 / 136848 Summary of the Invention

[0006] Meanwhile, light emitting devices have been desired to achieve slimming and improved brightness.

[0007] It is desirable to provide a light emitting device and an image display device that enable slimming and improved brightness.

[0008] A light-emitting device according to an embodiment of the present disclosure includes: a driving circuit substrate; and an element substrate having a first surface and a second surface, the first surface serving as a light-emitting surface, the second surface being on a side opposite to the first surface and opposite to the driving circuit substrate, the element substrate including a pixel array portion including a plurality of pixels arranged in an array, and the element substrate including two or more light-emitting elements, the two or more light-emitting elements having a mesa structure for each pixel.

[0009] An image display device according to an embodiment of the present disclosure includes a light emitting device. As the light emitting device, the image display device includes the light emitting device according to the embodiment of the present disclosure described above.

[0010] The light emitting device and the image display device according to the embodiment of the present disclosure are provided with two or more light emitting elements having a mesa structure for each pixel. This makes it possible to add redundancy to each pixel. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic cross-sectional view illustrating an example of a configuration of a light emitting device according to an embodiment of the present disclosure.

[0012] Figure 2 It shows Figure 1 A schematic diagram of an embodiment of a planar configuration of the entire light-emitting device is shown in FIG.

[0013] Figure 3 It is magnified Figure 2 Schematic diagram of a portion of a planar configuration of a light emitting device shown in FIG.

[0014] Figure 4 It is shown in Figure 1 Schematic plan view of an embodiment of the layout of the light-emitting element in each pixel of the light-emitting device shown in FIG.

[0015] Figure 5 It is used to describe control Figure 1 Schematic diagram of an embodiment of a method for measuring the brightness of each pixel of a light-emitting device shown in FIG.

[0016] Figure 6 It is used to describe control Figure 1 FIG. 1 is a diagram illustrating another embodiment of a method for measuring the brightness of each pixel of a light-emitting device shown in FIG.

[0017] Figure 7A Is used to describe Figure 1 Schematic cross-sectional view of an embodiment of a manufacturing process of a light emitting device is shown in FIG.

[0018] Figure 7B It shows Figure 7A Schematic cross-sectional view of the subsequent process.

[0019] Figure 7C It shows Figure 7B Schematic cross-sectional view of the subsequent process.

[0020] Figure 7D It shows Figure 7C Schematic cross-sectional view of the subsequent process.

[0021] Figure 7E It shows Figure 7D Schematic cross-sectional view of the subsequent process.

[0022] Figure 7F It shows Figure 7E Schematic cross-sectional view of the subsequent process.

[0023] Figure 7G It shows Figure 7F Schematic cross-sectional view of the subsequent process.

[0024] Figure 7H It shows Figure 7G Schematic cross-sectional view of the subsequent process.

[0025] Figure 7I It shows Figure 7H Schematic cross-sectional view of the subsequent process.

[0026] Figure 8A It shows Figure 7F Schematic cross-sectional view of the subsequent process.

[0027] Figure 8B It shows Figure 8A Schematic cross-sectional view of the subsequent process.

[0028] Figure 8C It shows Figure 8B Schematic cross-sectional view of the subsequent process.

[0029] Figure 8D It shows Figure 8C Schematic cross-sectional view of the subsequent process.

[0030] Figure 8E It shows Figure 8D Schematic cross-sectional view of the subsequent process.

[0031] Figure 8F It shows Figure 8E Schematic cross-sectional view of the subsequent process.

[0032] Figure 8G It shows Figure 8F Schematic cross-sectional view of the subsequent process.

[0033] Figure 8H It shows Figure 8G Schematic cross-sectional view of the subsequent process.

[0034] Figure 8I It shows Figure 8H Schematic cross-sectional view of the subsequent process.

[0035] Figure 8J It shows Figure 8I Schematic cross-sectional view of the subsequent process.

[0036] Figure 8K It shows Figure 8J Schematic cross-sectional view of the subsequent process.

[0037] Figure 8L It shows Figure 8K Schematic cross-sectional view of the subsequent process.

[0038] Figure 8M It shows Figure 8L Schematic cross-sectional view of the subsequent process.

[0039] Figure 8N It shows Figure 8M Schematic cross-sectional view of the subsequent process.

[0040] Figure 9are diagrams for describing luminance before correction (A) and luminance after correction (B) of respective pixels of a general light-emitting device according to a comparative example.

[0041] Figure 10 is a diagram for describing the relationship between the luminance of each pixel of a general light-emitting device and the luminance of the corresponding light-emitting element.

[0042] Figure 11 Is used to describe Figure 1 Graph showing the relationship between the luminance of each pixel of the light-emitting device shown in FIG.

[0043] Figure 12 Is used to describe Figure 1 Graphs of luminance before correction (A) and luminance after correction (B) of a corresponding light emitting element in each pixel of the light emitting device shown in FIG.

[0044] Figure 13 is a schematic diagram illustrating an example of a planar configuration of an entire light emitting device according to a modification example of the present disclosure.

[0045] Figure 14 It is magnified Figure 13 Schematic diagram of a portion of a planar configuration of a light emitting device shown in FIG.

[0046] Figure 15 1 is a perspective view showing an embodiment of a structure of an image display device according to an application example of the present disclosure.

[0047] Figure 16 It is shown in Figure 15 FIG. 1 is a schematic diagram of an embodiment of a wiring layout of an image display device shown in FIG.

[0048] Figure 17 is a perspective view showing an example of a configuration of an image display device according to an application example of the present disclosure.

[0049] Figure 18 It shows Figure 17 A perspective view of the configuration of the mounting substrate shown in FIG.

[0050] Figure 19 It shows Figure 18 A perspective view of the configuration of the unit substrate is shown in FIG.

[0051] Figure 20 : is a diagram illustrating an embodiment of an image display device according to an application example of the present disclosure. DETAILED DESCRIPTION

[0052] Next, with reference to the accompanying drawings, details of embodiments of the present disclosure will be described. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following embodiments. In addition, the present disclosure is not limited to the placement, size, and dimensional ratios of the corresponding structural elements in each figure. It should be noted that the description will be given in the following order.

[0053] 1. First Embodiment (Example of a Light-Emitting Device Including a Multiple Light-Emitting Elements Arranged in Each Pixel)

[0054] 1-1. Configuration of Light-Emitting Device

[0055] 1-2. Method for Manufacturing Light-Emitting Device

[0056] 1-3. Actions and Effects

[0057] 2. Modification (Another embodiment of the light-emitting device)

[0058] 3. Application Examples

[0059] <1. Implementation Method>

[0060] Figure 1 An example of a cross-sectional configuration of a light emitting device (light emitting device 1 ) according to an embodiment of the present disclosure is schematically shown. Figure 2 Schematically shown in Figure 1 The light emitting device 1 is suitable for an image display device called an LED display (for example, an image display device 100, see Figure 15 ).

[0061] (1-1. Configuration of Light-Emitting Device)

[0062] The light emitting device 1 is obtained by combining the element substrate 10 and the driving circuit substrate 30 via hybrid bonding. Figure 3As shown, the light-emitting device 1 has a display area 100A and a frame area 100B. The display area 100A is composed of a plurality of rectangular pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb) arranged in a two-dimensional manner, for example, and the frame area 100B is arranged around the display area 100A. The element substrate 10 has a surface 10S1 and a surface 10S2. The surface 10S1 serves as a light emitting surface. The surface 10S2 is on the side opposite to the surface 10S1. The driving circuit substrate 30 is stacked on the surface 10S2 side of the element substrate 10. The driving circuit substrate 30 has a surface 30S1 and a surface 30S2. The surface 30S1 is opposite to the element substrate 10. The surface 30S2 is on the side opposite to the surface 30S1. The driving circuit substrate 30 is provided with a driving circuit for controlling the driving of the plurality of light-emitting elements 11 arranged in the display area 100A, etc. In this embodiment, two or more (for example, four) mesa-structured light-emitting elements 11 are arranged for each color pixel Pr, Pg, and Pb.

[0063] In this embodiment, the element substrate 10 corresponds to a specific example of the "element substrate" according to the embodiment of the present disclosure. The surface 10S1 corresponds to the "first surface" according to the embodiment of the present disclosure. The surface 10S2 corresponds to the "second surface" according to the embodiment of the present disclosure. In addition, the display area 100A corresponds to a specific example of the "pixel array unit" according to the embodiment of the present disclosure. The display of red pixels Pr, green pixels Pg, and blue pixels Pb corresponds to a specific example of the "multiple pixels" according to the embodiment of the present disclosure. The driving circuit substrate 30 corresponds to a specific example of the "driving circuit substrate" according to the embodiment of the present disclosure.

[0064] The element substrate 10 includes a plurality of light emitting elements 11 obtained by separating a compound semiconductor layer 110 (see FIG. 7 ) extending in the display region 100A. For example, Figure 4As shown, multiple light-emitting elements 11 have a substantially circular planar shape and are arranged in an array in the row direction (e.g., the X-axis direction) and the column direction (e.g., the Y-axis direction). For example, within the arrayed rows and columns of the multiple light-emitting elements 11, four light-emitting elements are arranged in two rows and two columns, respectively, in the color pixels Pr, Pg, and Pb. An electrode layer 12 is formed on the light extraction surface (surface 11S1) of the multiple light-emitting elements 11, continuous with the multiple light-emitting elements 11. On the surface 11S2 of the multiple light-emitting elements 11, an electrode layer 115, an insulating layer 116, a protective layer 117, an insulating film 118A, and a reflective film 118B are formed. The electrode layer 115, insulating layer 116, and protective layer 117 are provided for each element. The insulating film 118A and the reflective film 118B are continuous with the multiple light-emitting elements 11. The element substrate 10 further includes an embedding layer 119, an insulating layer 17, and an insulating layer 18 on the driver circuit substrate 30 side. Embedding layer 119 embeds multiple light-emitting elements 11 from the surface 10S2 side. Embedding layer 119 includes plugs 15 provided for the corresponding elements. Insulating layer 17 includes pad portions 16A provided for the corresponding elements in display area 100A and pad electrodes 16B provided in frame area 100B. Insulating layer 18 forms a bonding surface to be bonded to drive circuit substrate 30 and includes multiple pad portions 19 that electrically and physically bond element substrate 10 and drive circuit substrate 30.

[0065] Light-emitting element 11 corresponds to a specific example of a "light-emitting element" according to an embodiment of the present disclosure. Light-emitting element 11 is a solid-state light-emitting element, such as a light-emitting diode (LED) chip, that emits light in a predetermined wavelength band from surface 11S1. An LED chip is a chip obtained by cutting a wafer from which crystals have been grown, and is not packaged in a package such as a molded resin. The size of an LED chip is, for example, 5µm or larger and 100µm or smaller, and is therefore referred to as a micro-LED.

[0066] The light emitting element 11 includes a first conductivity type layer 111 , an active layer 112 , and a second conductivity type layer 113 stacked in sequence, and the second conductivity type layer 113 has an upper surface (surface 11S 1 ) serving as a light exit surface.

[0067] For example, the first conductive type layer 111 is formed of an n-type GaN-based semiconductor material. The active layer 112 has, for example, a multi-quantum well structure in which InGaN and GaN are alternately stacked, and includes a light-emitting region therein. For example, light within the blue wavelength range of 430 nm to 500 nm can be extracted from the active layer 112. Furthermore, light having a wavelength corresponding to the ultraviolet region (ultraviolet light) can be extracted from the active layer 112. For example, the second conductive type layer 113 is formed of a p-type GaN-based semiconductor material.

[0068] The electrode layer 12 serves as a common electrode for the plurality of light-emitting elements 11 and is continuously formed on the respective surfaces 11S1 of the plurality of light-emitting elements 11. The electrode layer 12 is in ohmic contact with the second conductive type layer 113. For example, the electrode layer 12 is formed of a transparent electrode material such as zinc oxide (ZnO), ITO, indium zinc oxide (IZO), tin oxide (SnO), or TiO. For example, in the frame region 100B, the electrode layer 12 is electrically coupled to the pad electrode 16B via an opening H1 that penetrates the protective layer 117 and the embedding layer 119 and has a bottom portion exposed by the pad electrode 16B.

[0069] Electrode layer 115 is formed on the lower surface (surface 11S2) of first conductivity type layer 111 of light emitting element 11. Electrode layer 115 is in ohmic contact with first conductivity type layer 111. For example, electrode layer 115 is formed of a transparent conductive material such as a multilayer film (Ni / Au) of nickel (Ni) and gold (Au), ITO, or the like.

[0070] The insulating layer 116 is provided on the electrode layer 115. The insulating layer 116 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like.

[0071] On the driver circuit substrate 30 side, the light-emitting element 11 has a mesa structure including a first conductivity type layer 111, an active layer 112, and a portion of a second conductivity type layer 113. A surface 11S2 of the light-emitting element 11 and side surfaces of the first conductivity type layer 111, the active layer 112, and the second conductivity type layer 113, which have been processed into a mesa shape, are covered with a protective layer 117. The protective layer 117 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like.

[0072] In addition, the surface of the protective layer 117 and the side surface of the second conductive type layer 113 exposed from the protective layer 117 are covered with a stacked film including an insulating film 118A and a reflective film 118B. The stacked film is continuously formed for a plurality of light-emitting elements 11. The stacked film has an opening 118H on the surface 11S2 side of the light-emitting element 11, and the plug 15 is formed in the opening 118H.

[0073] The plug 15 applies a voltage to the corresponding first conductive type layers 111 of the plurality of light emitting elements 11. The plug 15 is formed by using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or an alloy thereof.

[0074] The embedded layer 119 embeds the plurality of light-emitting elements 11 and forms a flat laminated surface in the display region 100A and the frame region 100B on the driver circuit substrate 30 side. In the frame region 100B, the embedded layer 119 also forms a flat surface continuous with the surfaces 11S1 of the plurality of light-emitting elements 11. The embedded layer 119 is formed of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0075] An insulating layer 17 is provided on the driver circuit substrate 30 side of the embedded layer 119. Insulating layer 17, multiple pad portions 16A are formed in the display region 100A for the corresponding light-emitting elements 11A, and pad electrodes 16B and vias are formed in the frame region 100B. Insulating layer 17 is formed from, for example, silicon oxide (SiO) or silicon nitride (SiN). Pad portions 16A, pad electrodes 16B, and vias are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof.

[0076] Furthermore, an insulating layer 18 is provided on the driver circuit substrate 30 side of the insulating layer 17. This insulating layer 18 forms a bonding surface to be bonded to the driver circuit substrate 30. As described above, the insulating layer 18 forms a bonding surface to be bonded to the driver circuit substrate 30 and includes a plurality of pad portions 19 that electrically and physically bond the element substrate 10 to the driver circuit substrate 30. The insulating layer 18 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like. The pad portions 19 are formed, for example, using copper (Cu).

[0077] The element substrate 10 further includes a planarization layer 21, a partition wall layer 22, and a wavelength conversion layer 23 on the surface 10S1 side. For example, the partition wall layer 22 has openings 22H for the respective color pixels Pr, Pg, and Pg, and the wavelength conversion layer 23 is formed within the openings 22H. In addition, a reflective film 24 is provided between the partition wall layer 22 and the wavelength conversion layer 23.

[0078] The planarization layer 21 planarizes the light extraction surface (surface 11S1 ) of the display region 100A including the plurality of light emitting elements 11 arranged in an array. The planarization layer 21 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like.

[0079] When the light emitting device 100 is applied to an image display device 100, the partition wall layer 22 suppresses the occurrence of color mixing due to light leakage into mutually adjacent pixels of different colors. Figure 3 As shown, the partition wall layer 22 has, for example, a generally rectangular opening 22H for the corresponding color pixels Pr, Pg, and Pb arranged in an array. For example, in a cross-sectional view, the opening 22H has a surface inclined less than 90° relative to the surface of the partition wall layer 22 facing the light-emitting element 11. That is, the partition wall layer 22 has a side surface with a positive tapered shape between adjacent color pixels Pr, Pg, and Pb in a cross-sectional view. The partition wall layer 22 is preferably formed using a material with high thermal conductivity and high electrical conductivity. For example, the partition wall layer 22 is formed using a metal material such as copper (Cu), aluminum (Al), gold (Au), nickel (Ni), or platinum (Pt).

[0080] The wavelength conversion layer 23 converts the light emitted by the multiple light-emitting elements 11 arranged in each color pixel Pr, Pg, and Pb into the desired wavelength (for example, red (R), green (G), and blue (B)) and outputs it. The wavelength conversion layer 23 is formed in the opening 22H formed for each color pixel Pr, Pg, and Pb. Specifically, the red pixel Pr has a red wavelength conversion layer 23R that converts the light emitted by the four light-emitting elements 11 into light in the red wavelength range (red light). The green pixel Pg has a green wavelength conversion layer 23G that converts the light emitted by the four light-emitting elements 11 into light in the green wavelength range (green light). The blue pixel Pb has a blue wavelength conversion layer 23B that converts the light emitted by the four light-emitting elements 11 into light in the blue wavelength range (blue light).

[0081] The wavelength conversion layers 23R, 23G, and 23B can be formed using quantum dots corresponding to respective colors. Specifically, in the case of obtaining red light, for example, quantum dots can be selected from InP, GaInP, InAsP, CdSe, CdZnSe, CdTeSe, CdTe, etc. In the case of obtaining green light, for example, quantum dots can be selected from InP, GaInP, ZnSeTe, ZnTe, CdSe, CdZnSe, CdS, CdSeS, etc. In the case of obtaining blue light, quantum dots can be selected from ZnSe, ZnTe, ZnSeTe, CdSe, CdZnSe, CdS, CdZnS, CdSeS, etc. It should be noted that in the case where the light-emitting element 11 emits blue light as described above, the blue wavelength conversion layer 23B can be formed from a transparent resin layer having light transmittance.

[0082] A reflective film 24 is provided on the side surfaces of the opening 22H to efficiently extract the corresponding color light beams emitted from the plurality of light-emitting elements 11 and converted by the respective wavelength conversion layers 23R, 23G, and 23B from the light extraction surface (surface 23S1) of the wavelength conversion layer 23. The reflective film 24 is formed of a light-reflective metallic material. Examples of metallic materials used to form the reflective film 24 include metals with high reflectivity in the visible light region. Specific examples of such materials include silver (Ag), aluminum (Al), copper (Cu), gold (Au), platinum (Pt), rhodium (Rh), and alloys thereof.

[0083] It should be noted that, in the case where the partition wall layer 22 is formed by using the above-mentioned metal material having light reflectivity, the reflective film 24 does not necessarily have to be formed.

[0084] The optical structure 40 may be formed on the light emitting surface S1 side of the element substrate 10. The optical structure 40 includes a protective layer 41 and an on-chip lens layer 42. The protective layer 41 is formed on the display region 100A and the frame region 100B. The on-chip lens layer 42 is provided on the protective layer 41.

[0085] The protective layer 41 for protecting the surface of the wavelength conversion layer 23 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like.

[0086] The on-chip lens layer 42 is provided to cover the entire display area 100A and the entire frame area 100B. The on-chip lens layer 42 includes a plurality of on-chip lenses 42L having a predetermined curvature and outputting incident light in a predetermined direction. Figure 4 As shown, on-chip lenses 42L are arranged for the corresponding color pixels Pr, Pg, and Pb. The on-chip lens layer 42 comprises a light-transmitting material. For example, the on-chip lens layer 42 comprises a single-layer film containing one selected from the group consisting of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiCN), etc. Alternatively, the on-chip lens layer 42 comprises a stacked film containing at least two selected from the group consisting of silicon oxide (SiO), silicon nitride (SiN), and silicon oxynitride (SiCN).

[0087] For example, the driver circuit substrate 30 is provided with multiple constant current drive circuits that flow a fixed current to the multiple light-emitting elements 11 arranged in the display area 100A. The driver circuit substrate 30 includes a support substrate 31, an interlayer insulating layer 32, an insulating layer 33, and a pad portion 34. The interlayer insulating layer 32 is provided on the support substrate 31 and includes multiple wiring layers (e.g., wiring layers M1, M2, M3, M4, and M5) and vias for electrically coupling the wiring layers. The insulating layer 33 forms a bonding surface to be bonded to the element substrate 10. The pad portion 34 is embedded in the insulating layer 33.

[0088] For example, multiple constant current drive circuits include corresponding control elements 35 that control the current flowing into the light-emitting elements 11, and are electrically coupled to the multiple light-emitting elements 11 via the pad portions 19 provided on the bonding surface (surface 10S2) of the element substrate 10 and the pad portions 34 provided on the bonding surface (surface 30S1) of the drive circuit substrate 30.

[0089] Figure 5 and Figure 6 It is an explanation Figure 1 FIG1 is a diagram showing an embodiment of a method for controlling the brightness of each pixel (eg, red pixel Pr and green pixel Pg) of the light emitting device 1. It should be noted that Figure 5 and Figure 6 The arrows shown in ⊂ indicate the amounts of current flowing into the corresponding light emitting elements 11 .

[0090] For example, a plurality of light emitting elements 11 for corresponding color pixels Pr and Pg are connected to a constant current driving circuit respectively. Figure 5As shown, even in the case where one of the multiple light-emitting elements 11 provided for the corresponding color pixels Pr and Pg causes a bright spot defect due to a malfunction, the brightness of each pixel can be maintained by disconnecting the operation of the control element 35 connected to the malfunctioning light-emitting element 11 and controlling (here, increasing) the amount of current flowing into the other light-emitting elements 11.

[0091] For example, a plurality of light emitting elements 11 for corresponding color pixels Pr, Pg are connected to each other and to a constant current driving circuit. Figure 6 As shown, even if any one of the multiple light-emitting elements 11 set for the corresponding color pixels Pr and Pg fails and causes a poor bright spot, through fine-tuning, the current does not flow into the failed light-emitting element 11, but a large amount of current flows into other light-emitting elements 11, thereby maintaining the brightness of each pixel.

[0092] The interlayer insulating layer 32 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like.

[0093] Wiring layers M1, M2, M3, M4, and M5, and vias for electrically connecting the respective wiring layers, are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof. Insulating layer 33 is formed of, for example, silicon oxide (SiO), silicon nitride (SiN), or the like. Pad portion 34 is formed of, for example, copper (Cu).

[0094] (1-2. Method for Manufacturing Light-Emitting Device)

[0095] For example, the light emitting device 1 according to the present embodiment can be manufactured as follows. 7A to 7I and Figures 8A to 8N An example of a manufacturing process of the light emitting device 1 is shown.

[0096] First, if Figure 7A As shown, a sapphire substrate 114 is used as a growth substrate, and a compound semiconductor layer 110 is formed by epitaxial crystal growth using, for example, molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), or the like. Next, an electrode layer 115 and an insulating layer 116 are formed on the compound semiconductor layer 110 by, for example, chemical vapor deposition (CVD). Next, the surface of the insulating layer 116 is flattened by, for example, chemical mechanical polishing (CMP).

[0097] Next, if Figure 7B As shown, patterning is performed by etching the insulating layer 116, the electrode layer 115, and the compound semiconductor layer 110 using a photolithography technique, for example. Figure 7CAs shown, the sapphire substrate 114 is transferred in such a manner that the insulating layer 116 faces the support substrate 51, and then the sapphire substrate 114 is broken and singulated. Figure 7D As shown, the separate sapphire substrate 114 is bonded to the support substrate 52 with the insulating layer 116 facing the support substrate 52 .

[0098] Next, if Figure 7E As shown in FIG. 1 , the sapphire substrate 114 is removed by, for example, grinding / polishing, and the surface of the compound semiconductor layer 110 is flattened. Figure 7F As shown in FIG. 1 , an embedded layer 119 is formed on the support substrate 52 by, for example, CVD, and the embedded layer 119 is planarized. Figure 7G As shown, the edges of the embedding layer 119 and the support substrate 52 are trimmed. Figure 7H As shown in FIG, the embedding layer 119 is bonded to the support substrate 53 by, for example, plasma bonding. Figure 7I As shown, the support substrate 52 is peeled off. Next, the Figure 7I The part in the box X.

[0099] First, if Figure 8A As shown, patterning is performed by etching the insulating layer 116 and the electrode layer 115 provided on the compound semiconductor layer 110 using a photolithography technique, for example. Figure 8B As shown in FIG, for example, a portion of the compound semiconductor layer 110 is etched by a photolithography technique to form a mesa structure including a first conductive type layer 111, an active layer 112, and a portion of the second conductive type layer 113.

[0100] Next, an ALO film is formed on the upper surface of the insulating layer 116 and the side and bottom surfaces of the insulating layer 116, the electrode layer 115, and the mesa structure including the first conductive type layer 11, the active layer 112, and the second conductive type layer 113 by, for example, atomic layer deposition (ALD), and then a SiN film is further formed by, for example, CVD. Subsequently, the SiN film is etched by, for example, photolithography technology to form a protective layer 117 as a sidewall on the upper surface and side surface of the mesa structure. Figure 8C shown.

[0101] Next, for example, Figure 8D As shown, the second conductive type layer 113 exposed from the protective layer 117 is separated by, for example, photolithography technology to form a plurality of light emitting elements 11. Next, an ALO film is formed by, for example, ALD to cover the upper surface of the protective layer 117 and the side surfaces of the exposed light emitting elements 11. Figure 8EAs shown, an insulating film 118A and a reflective film 118B are sequentially formed by, for example, CVD, and then an opening 118H is formed on the upper surface of the mesa structure.

[0102] Then, if Figure 8F As shown in FIG, an embedded layer 119 for planarization is formed again by, for example, CVD. Figure 8G As shown in FIG, the plug 15 for the corresponding light emitting element 11 and the insulating layer 17 embedded with the plurality of pad portions 16A and the pad electrode 16B are formed. Figure 8H As shown in FIG, the insulating layer 17 is made thicker, and the insulating layer 18 is formed on the insulating layer 17. Subsequently, as shown in FIG. Figure 8I As shown, trimming is performed on their edges.

[0103] Next, if Figure 8J As shown in FIG. 1 , openings 18H are formed above the corresponding pad portions 16A and the corresponding pad electrodes 16B. Figure 8K As shown, a plurality of pad portions 19 are formed by embedding Cu, for example, in openings 18H. Subsequently, the surfaces of insulating layer 18 and the plurality of pad portions 19 are polished by, for example, CMP to planarize the bonding surface to be bonded to drive circuit substrate 30.

[0104] Next, if Figure 8L As shown in FIG, a plurality of pad portions 19 are bonded to a plurality of pad portions 34 of a driver circuit substrate 30 that has been formed separately by hybrid bonding. Figure 8M As shown, the support substrate 53 is peeled off. Figure 8N As shown in FIG, for example, an ITO film is formed by CVD, and then, for example, the ITO film is patterned by photolithography to form the electrode layer 12. Next, as shown in FIG. Figure 8N As shown in FIG, for example, the insulating layer 13 is formed by CVD. Subsequently, by photolithography, an opening is formed between adjacent light emitting elements 11, and an opening H1 that reaches the pad electrode 16B is formed. Next, as shown in FIG. Figure 8N As shown in , for example, a stacked film of Ti / W is formed by CVD, and then the extraction electrode 14 is formed by patterning the stacked film by a photolithography technique, for example.

[0105] Next, for example, a planarization layer 21 and a partition wall layer 22 are formed in sequence by CVD. Subsequently, for example, an opening 22H is made in the partition wall layer 22 of the corresponding pixel by photolithography technology. Next, an Al film is formed on the upper surface of the partition wall layer 22 and the side surface and bottom surface of the opening 22H by CVD, for example, and then the Al film formed on the upper surface of the partition wall layer 22 and the bottom surface of the opening 22H is removed by etching back, and a reflective film 24 is formed on the side surface of the opening 22H. Next, for example, a wavelength conversion layer 23 (23R, 23G and 23B) for the corresponding color is formed in the opening 22H by a coating method such as an inkjet method. Subsequently, a protective layer 41 is formed on the partition wall layer 22 and the wavelength conversion layer 23, and then the on-chip lens layer 42 is bonded. In this way, a Figure 1 The lighting device 1 is shown.

[0106] (1-3. Actions and Effects)

[0107] The light emitting device 1 of this embodiment has two or more (eg, four) light emitting elements 11 of a mesa structure for each color pixel Pr, Pg, Pb. This makes it possible to add redundancy to each pixel. A description will be provided below.

[0108] To improve the resolution of light-emitting devices using LEDs as light sources, it is necessary to reduce the pixel pitch and improve the mesa structure, both of which constitute the associated pixels. The term "mesa" refers to the light-emitting portion (or individual light-emitting element) of an image display device. However, when the LED mesa structure is refined, luminous efficiency deteriorates dramatically due to peripheral effects in regions below 1μm, for example, and the internal quantum efficiency (IQE) varies significantly.

[0109] Generally, when a light emitting device includes an LED for each pixel, no redundancy is added to the pixel. Therefore, even if one pixel does not meet the required brightness value, it becomes a faulty chip.

[0110] To address this issue, there's a method for creating multiple LED mesas per pixel. As mentioned above, multiple LED mesas can be created by covering the crystal growth substrate with a mask layer having multiple openings and selectively growing one or more semiconductor rods using MOCVD. However, using MOCVD can be difficult to control height. Forming fine LED mesas can be challenging, as the mesas have varying brightness due to their varying heights. Furthermore, the mesas themselves grow perpendicular to the crystal growth substrate, leading to disadvantages in light collection.

[0111] In contrast, according to this embodiment, a plurality of light-emitting elements 11 separated by etching of the compound semiconductor layer 110 are arranged for each pixel (e.g., red pixel Pr, green pixel Pg, blue pixel Pb). This makes it possible to add redundancy to each pixel and reduce brightness variations between pixels.

[0112] Figure 9 (A) Brightness variation and (B) corrected brightness variation among pixels P1, P2, P3, and P4 of a conventional light-emitting device 100 according to a comparative example are shown. When brightness variation exists in each pixel of a light-emitting device 1000 in which a light-emitting element 111 is arranged for each pixel, the brightness variation in pixel P is corrected, for example, by adjusting the brightness levels of other pixels to the brightness level of the pixel with the lowest brightness. That is, as shown in FIG8(A), when four pixels P1, P2, P3, and P4 arranged in two rows and two columns have brightness levels of 30, 100, 50, and 70, respectively, as shown in FIG8(B), the brightness levels of pixels P2, P3, and P4 are adjusted to the brightness level of pixel P1 with the lowest brightness.

[0113] like Figure 10 and Figure 11 As shown, in the light emitting device 1000, the light emitting elements 11 are arranged for the corresponding pixels and there is a brightness variation between the light emitting elements 11. Figure 10 As shown in FIG. 1 , the light-emitting elements 11 arranged for the respective pixels P represent the brightness of the pixels P as they are. As described above, in the case where there is a brightness variation in the pixel P, the brightness levels of the other pixels are adjusted to the brightness level of the pixel with the lowest brightness, and the brightness level of the light-emitting device 1000 becomes 30. In contrast, even if there is a brightness variation in the light-emitting elements 11 of the light-emitting device 1 according to the present embodiment, the average brightness of the four light-emitting elements 11 in the pixel is used as the brightness of each of the pixels P1, P2, P3, and P4. Therefore, as Figure 11 As shown, the respective luminances of the four pixels P1 , P2 , P3 , and P4 become 62.5, which is higher luminance than that of the light emitting device 1000 .

[0114] As described above, according to the present embodiment, it is possible to achieve refinement and improvement of the brightness of the light emitting device 1 and the image display device 100 provided with the light emitting device 1 .

[0115] Furthermore, according to this embodiment, a single wavelength conversion layer 23 (e.g., red wavelength conversion layer 23R, green wavelength conversion layer 23G, or blue wavelength conversion layer 23B) is arranged for adjacent light-emitting elements 11. This improves the unevenness and variation in brightness between pixels caused by the refinement of the mesa structure. Furthermore, this prevents the generation of defective pixels that act as bright spots, thereby improving productivity.

[0116] In addition, in this embodiment, a plurality of light emitting elements 11 provided for each color pixel Pr, Pg, Pb are connected to a constant current drive circuit. This makes it possible to individually control the light emission from each light emitting element 11.

[0117] Figure 12 The luminance before correction (A) and the luminance after correction (B) of the corresponding light emitting element 11 in each pixel P of the light emitting device 1 are shown. Figure 12 As shown in (A), among the four pixels P1, P2, P3 and P4 arranged in two rows and two columns, the average brightness of the four light-emitting elements 11 in the pixel P1 becomes 47.5, which is the lowest average brightness. The other pixels P2, P3 and P4 select the light-emitting element 11 with a higher brightness (higher IQE). In the case where the selected light-emitting element 11 meets the brightness of the pixel P1 with the lowest average brightness, their brightness is adjusted by selectively operating some of the light-emitting elements set in the pixels P2, P3, and P4. Specifically, for example, the pixel P2 can selectively operate two of the four light-emitting elements 11 with a brightness level of 100, and can disable the other two light-emitting elements 11, as shown in FIG. Figure 12 As shown in (B). Furthermore, for example, in pixel P4, three of the four light-emitting elements 11 with a brightness level of 70 can be selectively operated, while the remaining light-emitting elements 11 can be disabled. Control element 35 adjusts the current flow of the light-emitting elements 11 to be operated so that they have the brightness of pixel P1. This selective operation of high-efficiency light-emitting elements 11 reduces the load on the correction circuit, further reducing power consumption.

[0118] Next, modifications and application examples of the present disclosure will be described. Note that structural elements corresponding to those of the light emitting device 1 according to the above embodiment will be denoted by the same reference numerals as those of the above embodiment, and duplicate description will be omitted.

[0119] <2. Modifications>

[0120] Figure 13 An example of a planar configuration of an entire light emitting device (light emitting device 1A) according to a modification example of the present disclosure is schematically shown. Figure 14 Zoomed in Figure 13 A portion of a planar configuration of a light emitting device 1A is shown.

[0121] In the above embodiment, the substantially rectangular color pixels Pr, Pg, and Pb are composed of four light emitting elements 11 arranged in two rows and two columns. However, the present technology is not limited thereto.

[0122] The light-emitting device 1A of this modified example includes a display area 100A and a frame area 100B. The display area 100A includes a plurality of substantially regular hexagonal pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb) arranged in a honeycomb pattern. The frame area 100B is arranged around the display area 100A. Each of the color pixels Pr, Pg, and Pb is composed of, for example, seven light-emitting elements having a mesa structure. Even with this arrangement, effects similar to those of the above-described embodiment can be achieved.

[0123] <3. Application Examples>

[0124] (First application example)

[0125] Figure 15 1 is a perspective view showing an example of a schematic configuration of an image display device (image display device 100). The image display device 100 is a so-called LED display, and the light-emitting device according to the present disclosure (for example, the light-emitting device 1) is used as a display pixel. Figure 15 As shown, for example, the image display device 100 includes a display panel 120 and a control circuit 140 that drives the display panel 120 .

[0126] The display panel 120 is a display panel composed of a mounting substrate 120A and a counter substrate 120B stacked on each other. The counter substrate 120B has a screen display surface, a display area 100A in the center, and a frame area 100B as a non-display area around it.

[0127] Figure 16 1 shows an example of a wiring layout of a region corresponding to the display region 100A on the surface of the counter substrate 120B side of the mounting substrate 120A. Figure 16 As shown, for example, a plurality of data wirings 121 are formed to extend in a predetermined direction and are arranged in parallel at predetermined intervals in an area corresponding to the display area 100A on the surface of the mounting substrate 120A. For example, the area corresponding to the display area 100A on the surface of the mounting substrate 120A further includes a plurality of scan wirings 122 extending in a direction intersecting (e.g., orthogonal) with the data wirings 121, and a plurality of scan wirings 125 are arranged in parallel at predetermined intervals. The data wirings 121 and the scan wirings 122 are made of a conductive material such as Cu.

[0128] For example, the scan wiring 122 is formed on the topmost layer and on an insulating layer (not shown) formed on the surface of a base material. Note that the base material of the mounting substrate 120A includes, for example, a silicon substrate, a resin substrate, or the like. The insulating layer on the base material includes, for example, SiN, SiO, aluminum oxide (AlO), or a resin material. Meanwhile, the data wiring 121 is formed in a layer different from the topmost layer including the scan wiring 122 (for example, a layer below the topmost layer). The data wiring 121 is formed, for example, in the insulating layer on the base material.

[0129] The intersections of the data wiring 121 and the scan wiring 122 and their surroundings serve as display pixels 123. In the display region 100A, a plurality of display pixels 123 are arranged in a matrix. For example, the color pixels Pr, Pg, and Pb of the light emitting device 1 are implemented as display pixels 123.

[0130] For example, the light-emitting device 1 is provided with a pair of terminal electrodes for the color pixels Pr, Pg, and Pb, or is provided with a common terminal electrode and a terminal electrode for the color pixels Pr, Pg, and Pb. One terminal electrode is electrically coupled to the data wiring 121, and the other terminal electrode is electrically coupled to the scan wiring 125. For example, one terminal electrode is electrically coupled to the pad electrode 121B at the end of the branch 121A of the data wiring 121. In addition, for example, the other terminal electrode is electrically connected to the pad electrode 122B at the end of the branch 122A of the scan wiring 122.

[0131] For example, Figure 16 As shown, pad electrodes 121B and 122B are formed on the uppermost layer and provided at portions where the corresponding light emitting devices 1 are mounted. Here, the pad electrodes 121B and 122B include a conductive material such as Au (gold), for example.

[0132] For example, the mounting substrate 120A is further provided with a plurality of support columns (not shown) for adjusting the interval between the mounting substrate 120A and the counter substrate 120B. The support columns may be provided in a region opposite to the display region 100A or in a region opposite to the frame portion 100B.

[0133] The counter substrate 120B is composed of, for example, a glass substrate, a resin substrate, or the like. The counter substrate 120B may have a flat surface on the light-emitting device 1 side, but preferably has a roughened surface. The roughened surface may be provided over the entire area facing the display area 100A, or may be provided only in the area facing the display pixels 123. The roughened surface has fine irregularities, into which light emitted from the color pixels Pr, Pg, and Pb enters. For example, the irregularities can be formed on the roughened surface by sandblasting or dry etching.

[0134] The control circuit 140 drives the corresponding display pixel 123 (corresponding light emitting device 1) based on the image signal. For example, the control circuit 140 includes a data driver that drives the data wiring 121 coupled to the display pixel 123 and a scan driver that drives the scan wiring 122 coupled to the display pixel 123. Figure 15 As shown, the control circuit 140 may be provided separately from the display panel 120 and may be coupled to the mounting substrate 120A via wiring, or may be mounted on the mounting substrate 120A.

[0135] (Second application example)

[0136] Figure 17 1 is a perspective view showing another configuration example of an image display device (image display device 200) using a light emitting device (e.g., light emitting device 1) according to the present disclosure. The image display device 200 is a so-called tiled display that uses a plurality of light emitting devices including LEDs as light sources. For example, Figure 17 As shown, the image display device 200 includes a display panel 220 and a control circuit 240 for driving the display panel 220 .

[0137] The display panel 220 is a display panel composed of an overlapping mounting substrate 220A and a counter substrate 220B. The counter substrate 220B has a surface that serves as an image display surface. This surface includes a display portion in its center and a frame region (not shown) that serves as a non-display area surrounding the display region. For example, the counter substrate 220B is positioned opposite the mounting substrate 220A, with a predetermined gap between them. It should be noted that the counter substrate 220B may be in contact with the upper surface of the mounting substrate 220A.

[0138] Figure 18 An example of the configuration of the mounting substrate 220A is schematically shown. Figure 18 As shown, the mounting substrate 220A includes a plurality of unit substrates 250 placed like patches. Figure 18 An embodiment is shown in which the mounting substrate 220A includes nine unit substrates 250 , but the number of the unit substrates 250 may be 10 or more or 8 or less.

[0139] Figure 19An example configuration of a unit substrate 250 is shown. For example, the unit substrate 250 includes multiple light-emitting devices 1 arranged similarly to a patch and a support substrate 260 that supports the light-emitting devices 1. Each unit substrate 250 also includes a control substrate (not shown). For example, the support substrate 260 can be implemented using a metal frame (metal plate), a wiring substrate, or the like. If the support substrate 260 is implemented using a wiring substrate, it can also serve as a control substrate. In this case, at least one of the support substrate 260 and the control substrate is electrically coupled to the corresponding light-emitting device 1.

[0140] (Third application example)

[0141] Figure 20 The external appearance of a transparent display 300 is shown. Transparent display 300 includes, for example, a display portion 310, an operating portion 311, and a housing 312. Display portion 310 utilizes a light emitting device according to the present disclosure (e.g., light emitting device 1). Transparent display 300 allows for displaying images, text information, and the like while allowing the background of display portion 310 to pass through.

[0142] Transparent display 300 includes a light-transmitting mounting substrate. Light-emitting device 1 is provided with electrodes, each formed from a light-transmitting conductive material, similar to the mounting substrate. Alternatively, the electrodes may have a structure that is difficult to visually identify by increasing their wiring width or by reducing the thickness of the wiring. Furthermore, for example, black can be displayed on transparent display 300 by superimposing a liquid crystal layer equipped with a drive circuit. This allows switching between a transparent mode and a black display mode by controlling the light distribution direction of the liquid crystal.

[0143] The present technology has been described above with reference to the embodiments, modifications, and application examples. However, the present technology is not limited thereto, and various modifications are possible. For example, in the above embodiments and other embodiments, examples have been described in which the light emitted from the light-emitting element 11 is blue light or ultraviolet light. However, the present technology is not limited thereto. For example, the light-emitting device 1 may use a light-emitting element that emits two or more types of light, such as a combination of blue and green light, or a combination of ultraviolet and green light.

[0144] Furthermore, in the above-described embodiment and the like, respective components included in the light emitting device 1 and the like have been specifically described, but all components are not necessarily included, and other components may be further provided.

[0145] Note that the effects described herein are for illustrative purposes only and that other effects may exist.

[0146] The present technology can be configured as follows. According to the present technology with the following configuration, two or more light-emitting elements having a mesa structure are provided for each pixel. This makes it possible to add redundancy to each pixel and achieve refinement and improvement of brightness. (1)

[0148] A light-emitting device, comprising:

[0149] a driving circuit substrate; and

[0150] An element substrate has a first surface and a second surface, the first surface serving as a light emitting surface, the second surface being on a side opposite to the first surface and facing the drive circuit substrate, the element substrate including a pixel array portion including a plurality of pixels arranged in an array form, and the element substrate including two or more light-emitting elements, the two or more light-emitting elements having a mesa structure for each pixel. (2)

[0152] The light emitting device according to (1), wherein the element substrate further includes a wavelength conversion layer provided for each pixel and converting a wavelength of light emitted from two or more light emitting elements arranged for each pixel. (3)

[0154] The light emitting device according to (1) or (2), further comprising:

[0155] The microlens layer includes a microlens for each pixel on one side of the first surface of the element substrate, the microlens outputting light emitted from two or more light emitting elements arranged for each pixel to a predetermined direction. (4)

[0157] The light emitting device according to any one of (1) to (3), wherein

[0158] The driving circuit substrate includes a plurality of constant current driving circuits through which a fixed current flows, and

[0159] The plurality of constant current driving circuits respectively include corresponding control elements for controlling currents flowing in the plurality of light emitting elements, and the plurality of constant current driving circuits are respectively coupled to the corresponding light emitting elements. (5)

[0161] The light emitting device according to any one of (1) to (4), wherein

[0162] The driving circuit substrate includes a plurality of constant current driving circuits through which a fixed current flows, and

[0163] A plurality of constant current drive circuits include respective control elements that control current flowing in the plurality of light emitting elements, and each constant current drive circuit is coupled to each of two or more light emitting elements arranged for each pixel. (6)

[0165] The light emitting device according to (5), wherein two or more light emitting elements arranged for each pixel are coupled to each other and electrically coupled to the constant current drive circuit. (7)

[0167] A light emitting device according to any one of (1) to (6), wherein the drive circuit substrate has a third surface opposite to the second surface of the element substrate, and a fourth surface arranged on a side opposite to the third surface, and includes a plurality of constant current drive circuits that flow a fixed current. (8)

[0169] The light emitting device according to (7), wherein

[0170] The second surface of the element substrate is further provided with a plurality of first pad portions electrically coupled to the plurality of light emitting elements via plugs.

[0171] The third surface of the driving circuit substrate is further provided with a plurality of second pad portions electrically coupled to corresponding constant current driving circuits, and

[0172] The plurality of light emitting elements are electrically coupled to the plurality of constant current driving circuits via the plurality of first pad portions and the plurality of second pad portions. (9)

[0174] An image display device, comprising:

[0175] A light-emitting device comprising:

[0176] a driving circuit substrate, and

[0177] An element substrate has a first surface and a second surface, the first surface serving as a light emitting surface, the second surface being on a side opposite to the first surface and facing the drive circuit substrate, the element substrate including a pixel array portion including a plurality of pixels arranged in an array form, and the element substrate including two or more light-emitting elements, the two or more light-emitting elements having a mesa structure for each pixel.

[0178] This application claims the benefit of Japanese Priority Patent Application JP 2023-024685 filed with the Japan Patent Office on February 20, 2023, the entire contents of which are incorporated herein by reference.

[0179] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A light-emitting device, comprising: drive circuit substrate; as well as An element substrate having a first surface and a second surface, the first surface serving as a light emitting surface, the second surface being on a side opposite to the first surface and facing the drive circuit substrate, the element substrate including a pixel array portion including a plurality of pixels arranged in an array form, and the element substrate including two or more light-emitting elements, the two or more light-emitting elements having a mesa structure for each of the pixels.

2. The light emitting device according to claim 1, wherein The element substrate further includes a wavelength conversion layer that is provided for each of the pixels and converts the wavelength of light emitted from two or more light emitting elements arranged for each of the pixels.

3. The light emitting device according to claim 1, further comprising: A microlens layer includes, on one side of the first surface of the element substrate, a microlens for each of the pixels, the microlens outputting light emitted from two or more light emitting elements arranged for each of the pixels in a predetermined direction.

4. The light emitting device according to claim 1, wherein The driving circuit substrate includes a plurality of constant current driving circuits through which a fixed current flows, and The plurality of constant current driving circuits respectively include corresponding control elements for controlling currents flowing in the plurality of light emitting elements, and the plurality of constant current driving circuits are respectively coupled to the corresponding light emitting elements. The light emitting device according to claim 1 , wherein: The driving circuit substrate includes a plurality of constant current driving circuits through which a fixed current flows, and The plurality of constant current drive circuits include corresponding control elements for controlling current flowing in the plurality of light emitting elements, and each of the constant current drive circuits is coupled to each of two or more light emitting elements arranged for each of the pixels. The light emitting device according to claim 5 , wherein: The two or more light emitting elements arranged for each pixel are coupled to each other and electrically coupled to the constant current driving circuit.

7. The light emitting device according to claim 1, wherein The drive circuit substrate has a third surface opposite to the second surface of the element substrate and a fourth surface arranged on a side opposite to the third surface, and includes a plurality of constant current drive circuits through which a fixed current flows.

8. The light emitting device according to claim 7, wherein: The second surface of the element substrate is further provided with a plurality of first pad portions electrically coupled to the plurality of light emitting elements via plugs. The third surface of the driving circuit substrate is further provided with a plurality of second pad portions electrically coupled to the corresponding constant current driving circuits, and The plurality of light emitting elements are electrically coupled to the plurality of constant current driving circuits via the plurality of first pad portions and the plurality of second pad portions.

9. An image display device comprising: A light-emitting device comprising: a driving circuit substrate, and An element substrate having a first surface and a second surface, the first surface serving as a light emitting surface, the second surface being on a side opposite to the first surface and facing the drive circuit substrate, the element substrate including a pixel array portion including a plurality of pixels arranged in an array form, and the element substrate including two or more light-emitting elements, the two or more light-emitting elements having a mesa structure for each of the pixels.

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