Light emitting device and image display device

Abstract

A light emitting device according to one embodiment of the present disclosure is provided with: a drive substrate; a compound semiconductor layer which has a first surface that faces the drive substrate and a second surface that is on the opposite side of the first surface, and in which a first conductivity-type layer, an active layer, and a second conductivity-type layer are sequentially stacked in this order from the drive substrate side; a first separation groove that is formed from the first surface side and separates the first conductivity-type layer and the active layer for each pixel; a second separation groove that is formed from the second surface side at a position at which the second separation groove faces the first separation groove and separates a part of the second conductivity-type layer for each pixel; and a first metal film that is provided along the side surface and the bottom surface of the second separation groove and has light reflectivity.

Description

Light-emitting device and image display device

[0001] The present disclosure relates to a light-emitting device and an image display device including the light-emitting device.

[0002] For example, Patent Document 1 discloses that in a semiconductor light-emitting device for headlight use, crosstalk can be suppressed by forming light-reflecting grooves on the surface of the semiconductor layer between adjacent light-emitting segments.

[0003] JP 2015-156431 A

[0004] Incidentally, in a light emitting device using a micro LED (Light Emitting Diode), it is desired to reduce crosstalk as well as to narrow the pitch.

[0005] It is desirable to provide a light emitting device that can reduce the pitch and suppress crosstalk, and an image display device including the same.

[0006] A light emitting device according to one embodiment of the present disclosure includes a drive substrate, a compound semiconductor layer having a first surface facing the drive substrate and a second surface opposite the first surface, and in which a first conductivity type layer, an active layer, and a second conductivity type layer are stacked in this order from the drive substrate side, a first separation groove provided on the first surface side and separating the first conductivity type layer and the active layer for each pixel, a second separation groove provided on the second surface side at a position facing the first separation groove and separating a portion of the second conductivity type layer for each pixel, and a first metal film having light reflectivity provided along the side and bottom surfaces of the second separation groove.

[0007] An image display device according to an embodiment of the present disclosure includes a light-emitting device, and the light-emitting device includes the light-emitting device according to the embodiment of the present disclosure.

[0008] In the light-emitting device according to an embodiment of the present disclosure and the image display device according to an embodiment, a first separation groove is provided on a first surface of the compound semiconductor layer facing the drive substrate, and a second separation groove is provided on a second surface opposite the first surface, and a light-reflective metal film is provided along the side and bottom surfaces of the second separation groove, thereby reducing stray light and light leakage to adjacent pixels.

[0009] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a light-emitting device according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view schematically illustrating an example of the overall planar configuration of the light-emitting device illustrated in FIG. 1. FIG. 3 is a partially enlarged schematic view of the planar configuration of the light-emitting device illustrated in FIG. 2. FIG. 4 is a partially enlarged schematic view of the cross-sectional configuration of the light-emitting section illustrated in FIG. 1. FIG. 5A is a cross-sectional view schematically illustrating an example of a manufacturing process for the light-emitting device illustrated in FIG. 1. FIG. 5B is a cross-sectional view schematically illustrating a process subsequent to FIG. 5A. FIG. 5C is a cross-sectional view schematically illustrating a process subsequent to FIG. 5B. FIG. 5D is a cross-sectional view schematically illustrating a process subsequent to FIG. 5C. FIG. 5E is a cross-sectional view schematically illustrating a process subsequent to FIG. 5D. FIG. 5F is a cross-sectional view schematically illustrating a process subsequent to FIG. 5E. FIG. 5G is a cross-sectional view schematically illustrating a process subsequent to FIG. 5F. FIG. 5H is a cross-sectional view schematically illustrating a process subsequent to FIG. 5G. FIG. 5I is a cross-sectional view schematically illustrating a process subsequent to FIG. 5H. FIG. 6A is a cross-sectional view schematically illustrating a process subsequent to FIG. 5I. FIG. 6B is a schematic cross-sectional view showing a step subsequent to FIG. 6A. FIG. 6C is a schematic cross-sectional view showing a step subsequent to FIG. 6B. FIG. 6D is a schematic cross-sectional view showing a step subsequent to FIG. 6C. FIG. 6E is a schematic cross-sectional view showing a step subsequent to FIG. 6D. FIG. 6F is a schematic cross-sectional view showing a step subsequent to FIG. 6E. FIG. 6G is a schematic cross-sectional view showing a step subsequent to FIG. 6F. FIG. 6H is a schematic cross-sectional view showing a step subsequent to FIG. 6G. FIG. 6I is a schematic cross-sectional view showing a step subsequent to FIG. 6H. FIG. 6J is a schematic cross-sectional view showing a step subsequent to FIG. 6I. FIG. 6K is a schematic cross-sectional view showing a step subsequent to FIG. 6J. FIG. 6L is a schematic cross-sectional view showing a step subsequent to FIG. 6K. FIG. 6M is a schematic cross-sectional view showing a step subsequent to FIG. 6L. FIG. 6N is a schematic cross-sectional view showing a step subsequent to FIG. 6M. FIG. 6O is a schematic cross-sectional view showing a step subsequent to FIG. 6N. FIG. 6P is a schematic cross-sectional view showing a step subsequent to FIG. 6O. Fig. 6Q is a schematic cross-sectional view showing a step subsequent to Fig. 6P. Fig. 6R is a schematic cross-sectional view showing a step subsequent to Fig. 6Q. Fig. 6S is a schematic cross-sectional view showing a step subsequent to Fig. 6R. Fig. 6T is a schematic cross-sectional view showing a step subsequent to Fig. 6S. Fig. 7 is a schematic cross-sectional view showing an example of the configuration of a general light-emitting device. Fig. 8 is a schematic cross-sectional view according to Modification 1 of the present disclosure. Fig. 9 is a schematic cross-sectional view according to Modification 2 of the present disclosure. Fig. 10 is a schematic cross-sectional view according to Modification 3 of the present disclosure.FIG. 11 is a schematic cross-sectional view according to Variation 4 of the present disclosure. FIG. 12 is a schematic cross-sectional view according to Variation 5 of the present disclosure. FIG. 13 is a schematic cross-sectional view according to Variation 6 of the present disclosure. FIG. 14 is a schematic cross-sectional view according to Variation 7 of the present disclosure. FIG. 15 is a schematic cross-sectional view according to Variation 8 of the present disclosure. FIG. 16 is a schematic cross-sectional view according to Variation 9 of the present disclosure. FIG. 17 is a schematic cross-sectional view according to Variation 10 of the present disclosure. FIG. 18 is a schematic diagram showing an example of a planar layout of a metal film and a pad electrode of a light-emitting device of the present disclosure. FIG. 19 is a schematic diagram showing another example of a planar layout of a metal film and a pad electrode of a light-emitting device of the present disclosure. FIG. 20 is a schematic diagram showing another example of a planar layout of a metal film and a pad electrode of a light-emitting device of the present disclosure. FIG. 21 is a schematic diagram showing an example of a planar layout of a metal film of a light-emitting device of the present disclosure. FIG. 22 is a schematic diagram showing another example of a planar layout of a metal film of a light-emitting device of the present disclosure. Fig. 23 is a perspective view illustrating an example of the configuration of an image display device according to an application example of the present disclosure. Fig. 24 is a schematic diagram illustrating an example of a wiring layout of the image display device shown in Fig. 23. Fig. 25 is a perspective view illustrating an example of the configuration of an image display device according to an application example of the present disclosure. Fig. 26 is a perspective view illustrating the configuration of the mounting board shown in Fig. 25. Fig. 27 is a perspective view illustrating the configuration of the unit board shown in Fig. 26. Fig. 28 is a diagram illustrating an example of an image display device according to an application example of the present disclosure.

[0010] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following embodiment. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of the components shown in the drawings. The description will be given in the following order. 1. Embodiment (Example of a light-emitting device in which a light-reflecting film is provided on the side and bottom surfaces of a groove provided from the light-emitting surface side of a compound semiconductor layer) 1-1. Configuration of the light-emitting device 1-2. Method of manufacturing the light-emitting device 1-3. Actions and effects 2. Modifications 2-1. Modification 1 (Another example of a light-emitting device) 2-2. Modification 2 (Another example of a light-emitting device) 2-3. Modification 3 (Another example of a light-emitting device) 2-4. Modification 4 (Another example of a light-emitting device) 2-5. Modification 5 (Another example of a light-emitting device) 2-6. Modification 6 (Another example of a light-emitting device) 2-7. Modification 7 (Another example of a light-emitting device) 2-8. Modification 8 (Another example of a light-emitting device) 2-9. 2-10. Modification 9 (another example of a light-emitting device) 2-11. Modification 11 (another example of a light-emitting device) 2-12. Modification 12 (another example of a light-emitting device) 3. Application example (example of an image display device)

[0011] 1. Embodiment Fig. 1 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1) according to an embodiment of the present disclosure. Fig. 2 is a schematic diagram illustrating an example of an overall planar configuration of the light-emitting device 1 illustrated in Fig. 1. The light-emitting device 1 is suitably applicable to an image display device known as an LED display (for example, the image display device 100 illustrated in Fig. 23 described below).

[0012] [1-1. Configuration of the Light-Emitting Device] The light-emitting device 1 has a display unit 100A in which a plurality of pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb) are arranged in a two-dimensional array, and a frame unit 100B provided around the display unit 100A. The light-emitting device 1 is, for example, configured such that a light-emitting unit 10 including a compound semiconductor layer 11 and a wavelength conversion unit 20 are stacked in this order on the surface 30S1 side of a drive substrate 30 having an opposing front surface (surface 30S1) and back surface (surface 30S2).

[0013] The light-emitting device 1 has a surface 11S1 facing the drive substrate 30 and a surface 11S2 opposite the surface 11S1, and includes a compound semiconductor layer 11 in which a first-conductivity-type layer 111, an active layer 112, and a second-conductivity-type layer 113 are stacked in this order from the drive substrate 30 side. The light-emitting device 1 has a groove 11U1 provided on the surface 11S1 side, which separates the first-conductivity-type layer 111 and the active layer 112 into individual pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb). The light-emitting device 1 has a groove 11U2 provided on the surface 11S2 side opposite the groove 11U1, which separates a portion of the second-conductivity-type layer 113 into individual pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb). The light-emitting device 1 has a light-reflective metal film 114 provided along the side and bottom surfaces of the groove 11U2.

[0014] Here, surface 11S1 corresponds to a specific example of a "first surface" according to one aspect of the present disclosure, and surface 11S2 corresponds to a specific example of a "second surface" according to one aspect of the present disclosure. Groove 11U1 corresponds to a specific example of a "first separation groove" according to one aspect of the present disclosure, and groove 11U2 corresponds to a specific example of a "second separation groove" according to one aspect of the present disclosure. Metal film 114 corresponds to a specific example of a "first metal film" according to one aspect of the present disclosure.

[0015] As described above, the light-emitting unit 10 has a plurality of pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb) arranged in a two-dimensional array in the display unit 100A. Specifically, the plurality of pixels have a substantially regular hexagonal planar shape, for example, as shown in FIG. 3 , and are arranged in a honeycomb pattern, for example. On the surface 11S1 side of the compound semiconductor layer 11, an electrode layer 121 and an insulating layer 122 are provided for each pixel, a protective layer 123 and a metal film 124 are provided continuously between the pixels, and an embedding layer 125 that embeds the pixels. Further formed on the surface 11S1 side are a plug 13 provided for each pixel, an insulating layer 15 including a pad portion 14A, a pad electrode 14B1, and a pad electrode 14B2, and an insulating layer 16 including a pad portion 17 that electrically and physically bonds the light-emitting unit 10 to the drive substrate 30, in this order.

[0016] The compound semiconductor layer 11 is a solid-state light-emitting element, such as an LED chip, that emits light in a predetermined wavelength band from the surface 11S1. The LED chip refers to an LED cut from a wafer used for crystal growth, and is not a packaged type covered with a molded resin or the like. The LED chip has a size of, for example, 5 μm to 100 μm, and is known as a micro LED.

[0017] The compound semiconductor layer 11 has a surface 11S1 facing the drive substrate 30 and a surface 11S2 opposite to the surface 11S1, and has a first conductivity type layer 111, an active layer 112, and a second conductivity type layer 113 stacked in this order from the drive substrate 30 side. An undoped layer 115 and a buffer layer 116 are further stacked in this order on the second conductivity type layer 113. The undoped layer 115 corresponds to a specific example of an "undoped semiconductor layer" according to one aspect of the present disclosure, and the buffer layer 116 corresponds to a specific example of a "buffer layer" according to one aspect of the present disclosure.

[0018] The first conductivity type layer 111 is formed of, for example, an n-type GaN-based semiconductor material. The active layer 112 has, for example, a multiple quantum well structure in which InGaN and GaN are alternately stacked, and has a light-emitting region within the layer. Light in the blue band of, for example, 430 nm to 500 nm is extracted from the active layer 112. Light with a wavelength corresponding to, for example, the ultraviolet region (ultraviolet light) may also be extracted from the active layer 112. The second conductivity type layer 113 is formed of, for example, a p-type GaN-based semiconductor material.

[0019] FIG. 4 is an enlarged schematic cross-sectional view of a portion of the light-emitting section 10 of the light-emitting device 1 shown in FIG.

[0020] The groove 11U1 is provided from the surface 11S1 side and separates the first conductivity type layer 111 and the active layer 112 into pixels (e.g., red pixels Pr, green pixels Pg, and blue pixels Pb). The groove 11U1 has a bottom width W1 that is wider than the bottom width W2 of the groove 11U2, and a forward tapered shape in which the angle (θ1) between the side surface and the bottom surface of the groove 11U1 is greater than 90°. A protective layer 123 is provided within the groove 11U1, covering both the side surface and the bottom surface. Similar to the protective layer 123, a metal film 124 is also provided within the groove 11U1 on the protective layer 123.

[0021] The groove 11U2 is provided at a position facing the groove 11U1 from the surface 11S2 side, and separates the undoped layer 115, the buffer layer 116, and a portion of the second-conductivity-type layer 113 for each pixel (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb). In other words, the second-conductivity-type layer 113 is continuous between the pixels. The groove 11U2 has, for example, inclined side surfaces. Specifically, the groove 11U2 has, for example, a forward tapered shape in which the angle (θ1) formed between the side surface and the bottom surface of the groove 11U2 is greater than 90°. A metal film 114 is provided within the groove 11U2, spanning the side surfaces and the bottom surface. As a result, light (emitted light L) emitted from the active layer 112, for example, in an oblique direction, is reflected by the metal film 114 and is prevented from entering the wavelength conversion layers 23 (e.g., the red wavelength conversion layer 23R, the green wavelength conversion layer 23G, and the blue wavelength conversion layer 23B) provided in the adjacent pixels. The groove 11U2 is further filled with a planarization layer 21, which will be described later.

[0022] The metal film 114 is provided along the side and bottom surfaces of the groove 11U2. In a plan view, the metal film 114 is provided across the entire display unit 100A. For example, as shown in FIG. 3, the metal film 114 has an opening 114H for each pixel (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb). The surface 11S2 of the compound semiconductor layer 11 is exposed in the opening 114H, allowing light emitted from the active layer 112 to be extracted to the light-emitting surface S1. The metal film 114 further extends to the frame unit 100B and is connected to a pad electrode 14B1 exposed at the bottom of an opening H1 (described later). The pad electrode 14B1 is electrically connected to the drive substrate 30. In other words, the metal film 114 also serves as wiring electrically connecting the drive substrate 30 and the second-conductivity-type layer 113. The metal film 114 includes a light-reflective metal material. Examples of metal materials having light reflectivity include aluminum (Al) and silver (Ag). The metal film 114 is formed using at least one of aluminum (Al) and silver (Ag).

[0023] The undoped layer 115 is provided on the second conductivity type layer 113 and is made of, for example, an undoped GaN-based semiconductor material.

[0024] The buffer layer 116 is provided on the undoped layer 115 and is made of, for example, a low-temperature grown GaN-based semiconductor material.

[0025] The electrode layer 121 is formed in contact with the surface 11S1 of the compound semiconductor layer 11. The electrode layer 121 is in ohmic contact with the first conductivity type layer 111, and is formed using a transparent conductive material such as a multilayer film (Ni / Au) of nickel (Ni) and gold (Au) or ITO.

[0026] The insulating layer 122 is provided on the surface opposite to the surface in contact with the surface 11S1 of the electrode layer 121. The insulating layer 122 is formed using, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0027] The protective layer 123 is provided continuously along the side and bottom surfaces of the groove 11U1 and the surface of the insulating layer 122 facing the drive substrate 30, and extends to the frame portion 100B. The protective layer 123 is formed using, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0028] The metal film 124 is provided along the side and bottom surfaces of the groove 11U1 and contains a metal material having optical reflectivity. The metal film 124 contains, for example, at least one of aluminum (Al) and silver (Ag). Here, the metal film 124 corresponds to a specific example of a "second metal film" according to one aspect of the present disclosure.

[0029] The embedded layer 125 is intended to flatten the surface of the light-emitting unit 10 that faces the drive substrate 30. The embedded layer 125 is formed using, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0030] The plugs 13 apply, for example, an anode voltage to the first conductivity type layers 111 separated for each pixel by the grooves 11U1. The plugs 13 are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof.

[0031] A plurality of pads 14A and vias are formed in the insulating layer 15. The pads 14A and vias are provided for each pixel (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) in the display unit 100A. The pads 14A and vias are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or an alloy thereof.

[0032] Further, pad electrodes 14B1 and 14B2 and vias are formed in the frame portion 100B within the insulating layer 15. The pad electrode 14B1 is used as a cathode terminal for applying a cathode voltage to the second conductivity type layer 113. The pad electrode 14B2 is used as an external connection terminal for connecting the light emitting device 1 to the outside. The pad electrodes 14B1 and 14B2 are each formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or an alloy thereof.

[0033] The insulating layer 15 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0034] Further provided on the drive substrate 30 side of the insulating layer 15 are an insulating layer 16 that forms a bonding surface with the drive substrate 30, and a pad portion 17 that is embedded in the insulating layer 16. The insulating layer 16 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN). The pad portion 17 is made of, for example, copper (Cu).

[0035] The wavelength conversion unit 20 is provided on the light emission surface S1 side of the light emission unit 10. The wavelength conversion unit 20 includes a planarization layer 21, a partition layer 22 having openings 22H for each pixel (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb), and a wavelength conversion layer 23 formed in the openings 22H. A reflective film 24 is further provided between the partition layer 22 and the wavelength conversion layer 23. A protective layer 25 is further provided on the light emission surface S1 side of the wavelength conversion layer 23, and a light reflecting film 26 and a light absorbing film 27 are provided in the protective layer 25. An on-chip lens layer 28 is further provided on the protective layer 25.

[0036] The planarization layer 21 is intended to planarize the surface on the surface 11S1 side of the compound semiconductor layer 11. The planarization layer 21 is formed of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0037] The partition wall layer 22 is intended to suppress color mixing due to light leakage between adjacent red, green, and blue pixels Pr, Pg, and Pb. The partition wall layer 22 has, for example, a honeycomb structure, similar to the pixels (e.g., red, green, and blue pixels Pr, Pg, and Pb). Specifically, the partition wall layer 22 has, for example, a substantially regular hexagonal opening 22H for each of the plurality of pixels (red, green, and blue pixels Pb) arranged in an array, similar to the metal film 114 (see, for example, FIG. 6Q). In cross-sectional view, the opening 22H has, for example, a surface inclined at an angle of less than 90° with respect to the surface 20S2 of the wavelength conversion unit 20 opposite the surface 20S1. In other words, the partition wall layer 22 has a forward tapered shape between adjacent red, green, and blue pixels Pr, Pg, and Pb. The partition layer 22 is preferably formed using a material with high thermal conductivity and electrical conductivity, such as a metal material such as copper (Cu), aluminum (Al), gold (Au), nickel (Ni), or platinum (Pt).

[0038] The wavelength conversion layer 23 is provided above the surface 11S2 of the compound semiconductor layer 11, and converts light emitted from the active layer 112 separated for each pixel (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) by the grooves 11U1 into light of a predetermined wavelength band (e.g., red (R) / green (G) / blue (B)). Specifically, the red pixel Pr is provided with a red wavelength conversion layer 23R that converts the light emitted from the active layer 112 into light of a red band (red light), the green pixel Pg is provided with a green wavelength conversion layer 23G that converts the light emitted from the active layer 112 into light of a green band (green light), and the blue pixel Pb is provided with a blue wavelength conversion layer 23B that converts the light emitted from the active layer 112 into light of a blue band (blue light).

[0039] Each wavelength conversion layer 23R, 23G, and 23B can be formed using quantum dots corresponding to each color. Specifically, when red light is obtained, the quantum dots can be selected from, for example, InP, GaInP, InAsP, CdSe, CdZnSe, CdTeSe, or CdTe. When green light is obtained, the quantum dots can be selected from, for example, InP, GaInP, ZnSeTe, ZnTe, CdSe, CdZnSe, CdS, or CdSeS. When blue light is obtained, the quantum dots can be selected from, for example, ZnSe, ZnTe, ZnSeTe, CdSe, CdZnSe, CdS, CdZnS, and CdSeS.

[0040] When blue light is emitted from the active layer 112 as described above, the blue wavelength conversion layer 23B may be formed of a light-transmitting resin layer. That is, a light-transmitting resin layer may be provided as the wavelength conversion layer 23B in the blue pixel Pb, from which light in substantially the same wavelength band as the light emitted from the active layer 112 is extracted. The red pixel Pr and the green pixel Pg, from which light in a wavelength band different from the light emitted from the active layer 112 is extracted, are provided with the wavelength conversion layers 23R and 23G containing the quantum dots described above.

[0041] Here, the blue pixel Pb corresponds to a specific example of a "first pixel" according to one aspect of the present disclosure. The red pixel Pr and the green pixel Pg correspond to a specific example of a "second pixel" according to one aspect of the present disclosure. The wavelength conversion layers 23R and 23G correspond to a specific example of a "wavelength conversion layer provided in the first pixel" according to one aspect of the present disclosure, and the quantum dots correspond to a specific example of a "color conversion material" according to one aspect of the present disclosure. The wavelength conversion layer 23B corresponds to a specific example of a "wavelength conversion layer provided in the second pixel" according to one aspect of the present disclosure.

[0042] The reflective film 24 is provided on the side surface of the opening 22H to efficiently extract the colored light emitted from the active layer 112 and converted in the wavelength conversion layers 23R, 23G, and 23B from the surface 22S1 of the wavelength conversion layer 23. The reflective film 24 is formed using a metal material having optical reflectivity. Examples of the metal material for the reflective film 24 include metals with high reflectivity in the visible light range. Specific examples of the metal material include silver (Ag), aluminum (Al), copper (Cu), gold (Au), platinum (Pt), rhodium (Rh), and alloys thereof.

[0043] It should be noted that the reflective film 24 does not necessarily have to be formed when the partition wall layer 22 is formed using the above-mentioned metal material having light reflectivity.

[0044] The protective layer 25 is for protecting the surface of the light emitting device 1, and is formed using, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0045] A light-reflecting film 26 is provided within the protective layer 25, spanning the red pixel Pr and the green pixel Pg. The light-reflecting film 26 selectively reflects light in a predetermined wavelength band. For example, the light-reflecting film 26 selectively reflects light in the blue wavelength band (blue light), and is provided, for example, above the wavelength conversion layers 23R, 23G provided in the red pixel Pr and the green pixel Pg. This improves the color purity of the red light and green light extracted from the red pixel Pr and the green pixel Pg, respectively. The light-reflecting film 26 is, for example, a distributed Bragg reflector (DBR).

[0046] The light absorbing film 27 selectively absorbs light in a predetermined wavelength band and is provided, for example, on the light reflecting film 26 in the protective layer 25. For example, the light absorbing film 27 selectively absorbs light in the blue wavelength band (blue light) and is provided, for example, above the wavelength conversion layers 23R, 23G provided in the red pixel Pr and the green pixel Pg. This improves the color purity of the red light and green light extracted from the red pixel Pr and the green pixel Pg, respectively. The light absorbing film 27 is, for example, a color filter.

[0047] The on-chip lens layer 28 is provided above the protective layer 25. The on-chip lens layer 28 is made of an optically transparent material, and is made of, for example, a single-layer film made of any of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiCN), etc., or a stacked film made of two or more of these materials. Here, the on-chip lens layer 28 corresponds to a specific example of a "lens" according to one aspect of the present disclosure.

[0048] The frame portion 100B has an opening H1 that penetrates the embedded layer 125 and the protective layer 123 and reaches the pad electrode 14B1. A metal film 114 extending from the display portion 100A is provided on the side and bottom surfaces of the opening H1. This electrically connects the second conductivity type layer 113 and the drive substrate 30.

[0049] The frame portion 100B further has an opening H2 that penetrates the on-chip lens layer 28, the protective layer 25, the partition layer 22, the planarizing layer 21, the embedded layer 125, and the protective layer 123 and reaches the pad electrode 14B2.

[0050] The drive substrate 30 is provided with a drive circuit that controls the driving of a plurality of pixels arranged in the display unit 100 A. The drive substrate 30 has, for example, a support substrate 31 made of silicon (Si), an interlayer insulating layer 32 provided on the support substrate 31 and including a plurality of wiring layers (e.g., wiring layers M1, M2, M3, M4, and M5) and vias that electrically connect the wiring layers, an insulating layer 33 that forms a bonding surface with the light-emitting unit 10, and a pad portion 34 that is embedded in the insulating layer 33.

[0051] The interlayer insulating layer 32 is formed using, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0052] The wiring layers M1, M2, M3, M4, and M5 and the vias electrically connecting the wiring layers are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof. The insulating layer 33 is formed using, for example, silicon oxide (SiO), silicon nitride (SiN), or the like. The pad portion 35 is formed using, for example, copper (Cu).

[0053] [1-2. Manufacturing Method of Light-Emitting Device] The light-emitting device 1 of the present embodiment can be manufactured, for example, as follows. Figures 5A to 5I and 6A to 6U show an example of a manufacturing process for the light-emitting device 1.

[0054] 5A , a compound semiconductor layer 11 is formed on a growth substrate 41 such as a silicon substrate by epitaxial crystal growth using a method such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). Subsequently, an electrode layer 121 and an insulating layer 122 are formed on the compound semiconductor layer 11 by, for example, chemical vapor deposition (CVD). Next, the surface of the insulating layer 122 is planarized by, for example, chemical mechanical polishing (CMP).

[0055] 5B, the insulating layer 122, the electrode layer 121, and the compound semiconductor layer 11 are etched and patterned using, for example, photolithography. Next, as shown in FIG. 5C, the growth substrate 41 is transferred to a support substrate 51 such as a silicon substrate so that the insulating layer 122 faces the support substrate 51, and then the growth substrate 41 is cut into individual pieces. Next, as shown in FIG. 5D, the individual pieces of the growth substrate 41 are bonded to a support substrate 52 so that the insulating layer 122 faces the support substrate 52.

[0056] 5E, the growth substrate 41 is removed by, for example, laser lift-off. Subsequently, as shown in FIG. 5F, a silicon nitride film, for example, is formed on the upper surface of the compound semiconductor layer 11 and on the side surfaces of the compound semiconductor layer 11, the electrode layer 121, and the insulating layer 122. Then, a buried layer 125 is formed on the support substrate 52.

[0057] Next, as shown in Fig. 5G, the embedded layer 125 is planarized, and then the edge of the support substrate 52 is trimmed. Subsequently, as shown in Fig. 5H, the embedded layer 125 is bonded to the support substrate 53 by, for example, plasma bonding, and then the support substrate 52 is peeled off, as shown in Fig. 5I. The area within the frame X shown in Fig. 5I will be enlarged and explained below.

[0058] 6A, the insulating layer 122 and the electrode layer 121 are etched and patterned using, for example, photolithography. Then, as shown in FIG. 6B, a groove 11U1 is formed to separate the first conductivity type layer 111 and the active layer 112 using, for example, photolithography.

[0059] Next, as shown in Fig. 6C, a protective layer 123 is formed by depositing, for example, a SiN film on the top surface of the insulating layer 122 and along the side and bottom surfaces of the groove 11U1, for example, by atomic layer deposition (ALD). Subsequently, as shown in Fig. 6D, a metal film 124 is deposited by, for example, CVD, and then an opening 124H is formed for each pixel. Next, as shown in Fig. 6E, a buried layer 125 is deposited again by, for example, CVD, to fill the groove 11U1 and flatten the surface.

[0060] Subsequently, as shown in Fig. 6F, an insulating layer 15 is formed for each pixel, in which a plug 13, a plurality of pad portions 14A, a pad electrode 14B1, and a pad electrode 14B2 are embedded. Next, as shown in Fig. 6G, the insulating layer 15 is thickened, and an insulating layer 16 is formed on the insulating layer 15. Subsequently, as shown in Fig. 6H, the end portions are trimmed.

[0061] Next, as shown in Fig. 6I, openings 16H penetrating the insulating layer 16 and the insulating layer 15 are formed on the pad portions 14A, the pad electrodes 14B1, and the pad electrodes 14B2, and then, as shown in Fig. 6J, Cu, for example, is embedded in the openings 16H to form a plurality of pad portions 17. Thereafter, as shown in Fig. 6K, the surfaces of the insulating layer 16 and the plurality of pad portions 17 are polished by, for example, CMP to flatten the bonding surface with the drive substrate 30, and then the plurality of pad portions 34 of the drive substrate 30, which are separately formed, and the plurality of pad portions 17 are bonded to each other by Cu-Cu bonding.

[0062] Next, as shown in FIG. 6L , the support substrate 53 is peeled off, and then, as shown in FIG. 6M , the buried layer 125 is ground by, for example, CMP to expose the compound semiconductor layer 11. Next, as shown in FIG. 6N , a hard mask HM is patterned on the surfaces of the compound semiconductor layer 11 and the buried layer 125 using, for example, photolithography. Next, as shown in FIG. 6O , a groove 11U2 is formed using, for example, photolithography to separate a portion of the undoped layer 115, the buffer layer 116, and the second conductivity type layer 113. Next, in a similar manner, an opening H1 is formed in the frame portion 100B, reaching the pad electrode 14B1.

[0063] 6P, after removing the hard mask HM, a metal film 114 is formed by, for example, CVD on the entire surfaces of the compound semiconductor layer 11 and the buried layer 125, including the side and bottom surfaces of the trench 11U2 and the side and bottom surfaces of the opening H1. Thereafter, the metal film 114 is patterned to form an opening 114H on the surface 11S2 of the compound semiconductor layer 11.

[0064] 6Q, after forming the planarization layer 21 and the partition layer 22 in this order by, for example, CVD, openings 22H are formed in the partition layer 22 above each pixel by, for example, photolithography. Subsequently, as shown in FIG. 6R, an Al film is formed on the top surface of the partition layer 22 and the side and bottom surfaces of the openings 22H by, for example, CVD, and then the Al film formed on the top surface of the partition layer 22 and the bottom surface of the openings 22H is removed by etch-back to form reflective films 24 on the side surfaces of the openings 22H.

[0065] Next, as shown in Fig. 6S, wavelength conversion layers 23 (23R, 23G, 23B) of each color are formed in the opening 22H by using a coating method such as an inkjet method. Thereafter, as shown in Fig. 6T, a protective layer 25 including a light-reflecting film 26 and a light-absorbing film 27 is formed on the partition layer 22 and the wavelength conversion layer 23, and then an on-chip lens layer 28 is bonded thereto. In this way, the light-emitting device 1 shown in Fig. 1 is completed.

[0066] [1-3. Actions and Effects] In the light-emitting device 1 according to the embodiment of the present disclosure, a compound semiconductor layer 11 has a pair of opposing surfaces (surfaces 11S1 and 11S2), and includes a first conductivity-type layer 111, an active layer 112, a second conductivity-type layer 113, an undoped layer 115, and a buffer layer 116 stacked in this order from the surface 11S1 side. Grooves 11U1 and 11U2 are provided on both surfaces 11S1 and 11S2. The grooves 11U1 and 11U2 are formed in positions facing each other, and a light-reflective metal film 114 is formed on the side and bottom of the groove 11U2, which is provided on the surface 11S2 side, which serves as the light extraction surface. This reduces stray light, light leakage, and the like. This makes it possible to suppress crosstalk between adjacent pixels (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb).

[0067] Furthermore, in the light-emitting device 1, a metal film 118 is formed on the side and bottom surfaces of the groove 11SU1 provided from the surface 11S1 side of the compound semiconductor layer 11. This allows stray light and light leaking to adjacent pixels to be reflected by the grooves 11U1 and 11U2, thereby further suppressing crosstalk between adjacent pixels (for example, the red pixel Pr, the green pixel Pg, and the blue pixel Pb).

[0068] 7 is a schematic diagram illustrating an example of a cross-sectional configuration of a typical light-emitting device 1000. In the light-emitting device 1000, an electrode layer 1117 made of, for example, ITO and an insulating layer 1118 are provided in this order on the light-emitting surface side of a plurality of light-emitting elements 1100 arranged in a two-dimensional array, for example. An opening 1118H is formed in the insulating layer 1118, and the electrode layer 1117 and the extraction electrode 1119 are connected through this opening 1118H. In this way, in the light-emitting device 1000, a cathode voltage is applied to the second conductivity-type layer 1113 of each light-emitting element 1100 via the extraction electrode 1119 and the electrode layer 1117.

[0069] In contrast, in light-emitting device 1 of the present embodiment, metal film 114 provided along the side and bottom surfaces of groove 11U2 that extends from surface 11S2 of compound semiconductor layer 11 to second-conductivity-type layer 113 is used as wiring that electrically connects second-conductivity-type layer 113 to drive substrate 30 and applies a cathode voltage to second-conductivity-type layer 113. This makes it possible to reduce ohmic drop compared to light-emitting device 1000 in which a cathode voltage is applied to second-conductivity-type layer 1113 via electrode layer 1117 that uses a transparent conductive material such as ITO, which has a relatively high electrical resistance.

[0070] 7, as described above, electrode layer 1117 for applying a cathode voltage is formed on second conductivity type layer 1113. Therefore, in light emitting device 1000, after removing the growth substrate, it is necessary to thin the compound semiconductor layer until second conductivity type layer 1113 is exposed.

[0071] In contrast, in the light-emitting device 1 of the present embodiment, as described above, the metal film 114, which also serves as wiring for applying a cathode voltage, is provided along the side and bottom surfaces of the groove 11U2 that extends from the surface 11S2 side of the compound semiconductor layer 11 to the second conductivity-type layer 113. This eliminates the need to thin the compound semiconductor layer 11 after removing the growth substrate 41, specifically, the step of removing the undoped layer 115 and the buffer layer 116. This simplifies the manufacturing process. In addition, it is possible to improve the in-plane uniformity of the surface 11S1 side of the compound semiconductor layer 11.

[0072] Next, modified examples 1 to 12 and application examples of the present disclosure will be described. Note that components corresponding to those of the light emitting device 1 of the above embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0073] 2. Modifications 2-1. Modification 1 FIG. 8 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1A) according to Modification 1 of the present disclosure.

[0074] The light emitting device 1A is obtained by removing the undoped layer 115 and the buffer layer 116 stacked on the second conductivity type layer 113 in the light emitting device 1 of the above embodiment. Except for this point, the configuration of the light emitting device 1A is substantially the same as the configuration of the light emitting device 1 of the above embodiment.

[0075] Light emitting device 1A can be manufactured in the same manner as light emitting device 1 up to the stage where individual growth substrates 41 are bonded to support substrate 52 so that insulating layer 122 faces the support substrate 52. In light emitting device 1A, after removing growth substrate 41, compound semiconductor layer 11 is thinned by, for example, grinding and polishing until second conductivity type layer 113 is exposed. After this, light emitting device 1A can be manufactured in the same manner as light emitting device 1.

[0076] In the light emitting device 1A of this modification, the undoped layer 115 and buffer layer 116 stacked on the second conductivity type layer 113 are removed. As a result, the groove 11U2A formed from the surface 11S2 side of the compound semiconductor layer 11 separates only a portion of the second conductivity type layer 113. Therefore, the groove 11U2A can be formed smaller than when separating the undoped layer 115, the buffer layer 116, and a portion of the second conductivity type layer 113, as in the above embodiment. This allows for a narrower pitch and a lower height of the light emitting device.

[0077] [2-2. Modification 2] FIG. 9 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1B) according to Modification 2 of the present disclosure.

[0078] In the light emitting device 1B of this modification, the undoped layer 115 and the buffer layer 116 are removed, as in the modification 1, and further, the groove 11U2 provided at the outer edge of the display unit 100A in the above embodiment etc. is omitted. Except for these points, the configuration of the light emitting device 1B is substantially the same as the configuration of the light emitting device 1 of the above embodiment.

[0079] In the light emitting device 1B of this modification, the undoped layer 115 and the buffer layer 116 stacked on the second conductivity type layer 113 are removed, and the second conductivity type layer 113 is extended from the outer edge of the display unit 100A to the frame unit 100B without forming the groove 11U2. Even with this configuration, the light emitting device 1B can achieve the same effects as those of the above embodiment and modification 1.

[0080] [2-3. Modification 3] FIG. 10 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1C) according to Modification 3 of the present disclosure.

[0081] In the light emitting device 1C, the groove 11U2 is filled with a metal film 114A. Except for this, the configuration of the light emitting device 1C is substantially the same as that of the light emitting device 1 of the above embodiment.

[0082] The metal film 114A is provided to fill the groove 11U2 and includes a metal material having light reflectivity. Examples of the metal material having light reflectivity include aluminum (Al) and silver (Ag). The metal film 114A is formed using at least one of aluminum (Al) and silver (Ag).

[0083] In the light emitting device 1C of this modified example, the groove 11U2 is filled with a metal film 114A, which makes it possible to further suppress crosstalk between adjacent pixels (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) compared to when the sides and bottom of the groove 11U2 are covered only with a thin metal film 114.

[0084] 2-4. Modification 4 FIG. 11 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1D) according to Modification 4 of the present disclosure.

[0085] In the light emitting device 1D, at the end of the compound semiconductor layer 11 extending into the frame portion 100B, a buried layer 125 is inserted between the compound semiconductor layer 11 and the metal film 114. Except for this point, the configuration of the light emitting device 1D is substantially the same as that of the light emitting device 1 of the above embodiment.

[0086] Even with this configuration, the light emitting device 1D can achieve the same effects as the light emitting device 1 of the above embodiment.

[0087] [2-5. Modification 5] FIG. 12 is a schematic diagram showing an example of the cross-sectional configuration of a light emitting device according to Modification 5 of the present disclosure (light emitting device 1E).

[0088] In the above embodiment, the metal film 114 is provided on the frame portion 100B and continues to the opening H1 at the bottom of which the pad electrode 14B1 used as a cathode electrode is exposed, but this is not limited to this. In the light-emitting device 1E of this modification, an opening H3 is provided in the frame portion 100B that reaches the compound semiconductor layer 11, and a metal film 114B is provided that is continuous with the side and bottom surfaces of the opening H3 and the side and bottom surfaces of the opening H1, electrically connecting the second conductivity-type layer 113 and the drive substrate 30. Except for this point, the configuration of the light-emitting device 1E is substantially the same as the configuration of the light-emitting device 1 of the above embodiment.

[0089] The metal film 114B electrically connects the drive substrate 30 and the second conductivity type layer 113. The metal film 114B is formed using, for example, aluminum copper (AlCu), copper (Cu), titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), tungsten (W), cobalt (Co), or the like.

[0090] In the light emitting device 1E of this modification, the connection to the pad electrode 14B1 exposed at the bottom of the opening H1 is made using a metal film 114B that is different from the metal film 114. This not only achieves the effects of the above embodiment, but also improves the degree of freedom in selecting materials for the metal film 114 for suppressing crosstalk and the metal film 114B for electrically connecting the second conductivity type layer 113 and the drive substrate 30.

[0091] 2-6. Modification 6 FIG. 13 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1F) according to Modification 6 of the present disclosure.

[0092] In the above embodiment, the metal film 114 provided on the surface 11S2 side of the compound semiconductor layer 11 extends from the display unit 100A to the bottom of the opening H1 where the pad electrode 14B1 is exposed, electrically connecting the second conductivity-type layer 113 and the drive substrate 30. However, this is not limiting. In the light-emitting device 1F of this modified example, the second conductivity-type layer 113 and the drive substrate 30 are electrically connected from the surface 11S1 side of the compound semiconductor layer 11. Specifically, the first conductivity-type layer 111 and the active layer are removed from the frame unit 100B to expose the second conductivity-type layer 113 on the surface 11S1 side. A plug 18 is connected to the second conductivity-type layer 113 exposed on the surface 11S2 side, thereby electrically connecting the second conductivity-type layer 113 and the drive substrate 30. Except for this point, the configuration of the light-emitting device 1E is substantially the same as the configuration of the light-emitting device 1 of the above embodiment.

[0093] In the light emitting device 1F of this modification, the second conductivity type layer 113 and the drive substrate 30 are electrically connected via a plug 18 from the surface 11S1 side opposite to the surface 11S2 serving as the light extraction surface of the compound semiconductor layer 11. In this way, in addition to the effects of the above embodiment, the manufacturing process can be simplified by forming the anode-side and cathode-side plugs together.

[0094] [2-7. Modification 7] FIG. 14 is a schematic diagram illustrating an example of a cross-sectional configuration of a light emitting device (light emitting device 1G) according to Modification 7 of the present disclosure.

[0095] In the above embodiment, an example in which the surface 11S2 of the compound semiconductor layer 11 is flat has been described, but this is not limiting. In the light emitting device 1G of this modified example, an uneven structure is formed on the surface 11S2 of the compound semiconductor layer 11, which serves as the light emitting surface. The uneven structure on the surface 11S2 of the compound semiconductor layer 11 is formed, for example, as shown in FIG. 6O , in a process of forming the groove 11U2 and then removing the hard mask HM. Alternatively, the unevenness on the surface 11S2 of the compound semiconductor layer 11 may be formed by a separate surface treatment. Except for this point, the configuration of the light emitting device 1E is substantially the same as the configuration of the light emitting device 1 of the above embodiment.

[0096] In the light emitting device 1G of this modification, an uneven shape is formed on the surface 11S2 of the compound semiconductor layer 11, which serves as the light emitting surface. This improves the light extraction efficiency in addition to the effects of the above embodiment.

[0097] [2-8. Modification 8] FIG. 15 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1H) according to Modification 8 of the present disclosure.

[0098] In the light emitting device 1H of this modification, an opening H4 is provided that penetrates the on-chip lens layer 28, the protective layer 25, and the partition layer 22 at a position corresponding to the opening H1 and separates a part of the planarizing layer 21. Except for this point, the configuration of the light emitting device 1H is substantially the same as that of the light emitting device 1 of the above embodiment.

[0099] [2-9. Modification 9] FIG. 16 is a schematic diagram showing an enlarged view of a part of an example of the planar configuration of a light-emitting device (light-emitting device 1I) according to Modification 9 of the present disclosure.

[0100] In the above embodiment, an example was shown in which a plurality of pixels (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) have a substantially regular hexagonal planar shape and are arranged in a honeycomb pattern, but this is not limited to this. The light emitting device 1I of this modified example has a plurality of pixels (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) that have a substantially square planar shape and are arranged in a lattice pattern. Except for this point, the configuration of the light emitting device 1I is substantially the same as that of the light emitting device 1 of the above embodiment.

[0101] Even with this configuration, the light emitting device 1J can achieve the same effects as the light emitting device 1 of the above embodiment.

[0102] [2-10. Modification 10] FIG. 17 is a schematic diagram showing an enlarged view of a portion of an example of the planar configuration of a light-emitting device (light-emitting device 1J) according to Modification 10 of the present disclosure.

[0103] In the above embodiment, an example was shown in which a plurality of pixels (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) have a substantially regular hexagonal planar shape and are arranged in a honeycomb pattern, but this is not limited to this. In the light emitting device 1J of this modified example, a plurality of pixels (e.g., red pixel Pr, green pixel Pg, and blue pixel Pb) have a substantially diamond-shaped planar shape and are arranged in an array. Except for this point, the configuration of the light emitting device 1B is substantially the same as that of the light emitting device 1 of the above embodiment.

[0104] Even with this configuration, the light emitting device 1J can achieve the same effects as the light emitting device 1 of the above embodiment.

[0105] 2-11. Modification 11 FIGS. 18 to 20 are schematic diagrams showing examples of planar layouts of the metal film 114, pad electrodes 14B1, and pad electrodes 14B2 in a light-emitting device (for example, light-emitting device 1) according to the present disclosure.

[0106] The pad electrodes 14B1 and 14B2 may be arranged in parallel along one side of the rectangular frame portion 100B, as shown in Fig. 18. The pad electrodes 14B1 and 14B2 may be arranged such that the pad electrode 14B1 is arranged along the short side of the rectangular frame portion 100B and the pad electrode 14B2 is arranged along the long side, as shown in Fig. 19. The pad electrodes 14B1 and 14B2 may be arranged such that the pad electrode 14B1 is arranged along the long side of the rectangular frame portion 100B and the pad electrode 14B2 is arranged along the short side, as shown in Fig. 20.

[0107] [2-12. Modification 12] FIGS. 21 and 22 are schematic diagrams showing an example of a planar layout of metal film 114B in a light emitting device (for example, light emitting device 1E) according to the present disclosure.

[0108] The metal film 114B may be formed partially so as to connect one side of the metal film 114 adjacent to the pad electrode 14B1 to the pad electrode 14B1 as shown in Fig. 21. The metal film 114B may be formed in a frame shape so as to surround the metal film 114 provided in a grid pattern in the display unit 100A as shown in Fig. 22.

[0109] 23 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 uses a light-emitting device according to the present disclosure (e.g., light-emitting device 1) as a display pixel. As shown in FIG. 23 , the image display device 100 includes a display panel 120 and a control circuit 140 that drives the display panel 120.

[0110] The display panel 120 is formed by stacking a mounting substrate 120A and an opposing substrate 120B. The surface of the opposing substrate 120B serves as an image display surface, with a display area (display section 100A) in the center and a frame section 100B, which is a non-display area, around the display area.

[0111] 24 shows an example of a wiring layout in a region of the surface of the mounting substrate 120A facing the counter substrate 120B, which corresponds to the display unit 100A. In the region of the surface of the mounting substrate 120A corresponding to the display unit 100A, a plurality of data wirings 134 are formed extending in a predetermined direction and arranged in parallel at a predetermined pitch, as shown in FIG. 24 . In the region of the surface of the mounting substrate 120A corresponding to the display unit 100A, a plurality of scan wirings 135 are further formed extending in a direction intersecting (e.g., perpendicular to) the data wirings 134 and arranged in parallel at a predetermined pitch. The data wirings 134 and the scan wirings 135 are made of a conductive material, such as Cu.

[0112] The scan lines 135 are formed, for example, in the outermost layer, for example, on an insulating layer (not shown) formed on the surface of the substrate. The substrate of the mounting board 120A is made of, for example, a silicon substrate or a resin substrate, and the insulating layer on the substrate is made of, for example, SiN, SiO, aluminum oxide (AlO), or a resin material. On the other hand, the data lines 134 are formed in a layer different from the outermost layer including the scan lines 135 (for example, a layer below the outermost layer), for example, in an insulating layer on the substrate.

[0113] The display pixels 136 are located near the intersections of the data lines 134 and the scan lines 135, and a plurality of the display pixels 136 are arranged in a matrix within the display unit 100A. Each of the display pixels 136 is equipped with, for example, one of the color pixels Pr, Pg, and Pb of the light-emitting device 1.

[0114] The light-emitting device 1 is provided with a pair of terminal electrodes, for example, one for each of the color pixels Pr, Pg, and Pb, or one common and the other for each of the color pixels Pr, Pg, and Pb. One of the terminal electrodes is electrically connected to a data wiring 134, and the other is electrically connected to a scan wiring 135. For example, one of the terminal electrodes is electrically connected to a pad electrode 134B at the tip of a branch 134A provided on the data wiring 134. Furthermore, for example, the other terminal electrode is electrically connected to a pad electrode 135B at the tip of a branch 135A provided on the scan wiring 135.

[0115] Each of the pad electrodes 134B, 135B is formed, for example, on the outermost layer and is provided at a location where each of the light emitting devices 1 is mounted, as shown in Fig. 24. Here, the pad electrodes 134B, 135B are made of a conductive material such as Au (gold).

[0116] The mounting substrate 120A is further provided with, for example, a plurality of support pillars (not shown) that regulate the distance between the mounting substrate 120A and the counter substrate 120B. The support pillars may be provided in the region facing the display unit 100A, or in the region facing the frame unit 100B.

[0117] The counter substrate 120B is made of, for example, a glass substrate or a resin substrate. The surface of the counter substrate 120B facing the light-emitting device 1 may be flat, but is preferably roughened. The roughened surface may be provided over the entire area facing the display unit 100A, or may be provided only in the area facing the display pixels 136. The roughened surface has fine irregularities that allow light emitted from the color pixels Pr, Pg, and Pb to enter the roughened surface. The irregularities on the roughened surface can be created by, for example, sandblasting or dry etching.

[0118] The control circuit 140 drives each display pixel 136 (each light-emitting device 1) based on a video signal. The control circuit 140 is configured, for example, with a data driver that drives the data wiring 134 connected to the display pixels 136 and a scan driver that drives the scan wiring 135 connected to the display pixels 136. For example, as shown in FIG. 23 , the control circuit 140 may be provided separately from the display panel 120 and connected to the mounting substrate 120A via wiring, or may be mounted on the mounting substrate 120A.

[0119] 25 is a perspective view showing another configuration example (image display device 200) of an image display device 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 tiling display that uses a plurality of light-emitting devices that use LEDs as light sources. As shown in FIG. 25 , the image display device 200 includes, for example, a display panel 220 and a control circuit 240 that drives the display panel 220.

[0120] The display panel 220 is formed by stacking a mounting substrate 220A and a counter substrate 220B on top of each other. The surface of the counter substrate 220B serves as an image display surface, with a display section in the center and a frame section surrounding the display section, which is a non-display area (neither of which is shown). The counter substrate 220B is disposed, for example, in a position opposite the mounting substrate 220A with a predetermined gap therebetween. Note that the counter substrate 220B may also be in contact with the top surface of the mounting substrate 220A.

[0121] Fig. 26 is a schematic diagram showing an example of the configuration of the mounting substrate 220A. For example, as shown in Fig. 26, the mounting substrate 220A is configured from a plurality of unit substrates 250 arranged in a tiled pattern. Note that Fig. 26 shows an example in which the mounting substrate 220A is configured from nine unit substrates 250, but the number of unit substrates 250 may be ten or more, or eight or less.

[0122] 27 shows an example of the configuration of a unit substrate 250. The unit substrate 250 has, for example, a plurality of light-emitting devices 1 arranged in a tiled pattern and a support substrate 260 that supports each of the light-emitting devices 1. Each unit substrate 250 also has a control substrate (not shown). The support substrate 260 is formed, for example, of a metal frame (metal plate) or a wiring substrate. If the support substrate 260 is formed of a wiring substrate, it can also serve as the control substrate. In this case, at least one of the support substrate 260 and the control substrate is electrically connected to each of the light-emitting devices 1.

[0123] 28 shows the appearance of a transparent display 300. The transparent display 300 has, for example, a display unit 310, an operation unit 311, and a housing 312. The display unit 310 uses a light-emitting device (for example, the light-emitting device 1) of the present disclosure. The transparent display 300 can display images and text information while allowing the background of the display unit 310 to be seen through.

[0124] In the transparent display 300, a light-transmitting substrate is used as the mounting substrate. Each electrode provided in the light-emitting device 1 is formed using a light-transmitting conductive material, similar to the mounting substrate. Alternatively, each electrode is structured to be less visible by increasing the wiring width or reducing the wiring thickness. Furthermore, the transparent display 300 can display black by, for example, overlaying a liquid crystal layer equipped with a drive circuit, and switching between transparent and black display is possible by controlling the light distribution direction of the liquid crystal.

[0125] The present technology has been described above with reference to the embodiments, Modifications 1 to 11, and application examples, but the present technology is not limited to the above embodiments, etc., and various modifications are possible. For example, in the above embodiments, etc., examples have been shown in which the light emitted from the compound semiconductor layer 11 is blue light or ultraviolet light, but the present technology is not limited to this. For example, the light-emitting device 1 may also use a light-emitting element that emits two or more types of light, such as blue light and green light, or ultraviolet light and green light.

[0126] Furthermore, in the above-described embodiments, each component constituting the light emitting device 1 etc. has been specifically listed and described, but it is not necessary to include all components, and other components may also be included.

[0127] Furthermore, the above modifications 1 to 11 can be combined with each other in any way.

[0128] The effects described in this specification are merely examples and are not limited to those described, and other effects may also be obtained.

[0129] The present disclosure can also be configured as follows. According to the present disclosure configured as follows, stray light and light leakage into adjacent pixels are reduced by providing a light-reflective metal film along the side and bottom of a groove provided from a second surface side of a compound semiconductor layer constituting a light-emitting section, which serves as a light extraction surface. This makes it possible to suppress crosstalk. (1) A light-emitting device comprising: a drive substrate; a compound semiconductor layer having a first surface facing the drive substrate and a second surface opposite the first surface, and including a first conductivity-type layer, an active layer, and a second conductivity-type layer stacked in this order from the drive substrate side; a first separation trench provided from the first surface side and separating the first conductivity-type layer and the active layer for each pixel; a second separation trench provided from the second surface side at a position facing the first separation trench and separating a portion of the second conductivity-type layer for each pixel; and a light-reflective first metal film provided along the side and bottom of the second separation trench. (2) The light-emitting device according to (1), wherein the first metal film also serves as wiring electrically connecting the drive substrate and the second conductivity type layer. (3) The light-emitting device according to (1) or (2), further comprising a second metal film, wherein the second metal film includes a metal material having light reflectivity and is provided along the side and bottom surfaces of the first isolation trench. (4) The light-emitting device according to any one of (1) to (3), wherein the first metal film includes at least one of aluminum and silver. (5) The light-emitting device according to (3), wherein the second metal film includes at least one of aluminum and silver. (6) The light-emitting device according to any one of (1) to (5), wherein the compound semiconductor layer further includes an undoped semiconductor layer and a buffer layer, wherein the undoped semiconductor layer and the buffer layer are stacked in this order on the second conductivity type layer. (7) The light emitting device according to any one of (1) to (6), wherein the first separation trench is filled with the first metal film. (8) The light emitting device according to any one of (1) to (7), wherein the width of the bottom surface of the first separation trench is wider than the width of the bottom surface of the second separation trench.(9) The light-emitting device according to any one of (1) to (8), wherein the side surface of the second separation trench is inclined at an angle of 90° or less. (10) The light-emitting device according to any one of (1) to (9), wherein the second conductivity type layer is continuous between the pixels. (11) The light-emitting device according to any one of (1) to (10), further comprising a wavelength conversion layer, wherein the wavelength conversion layer is provided above the second surface of the compound semiconductor layer and converts light emitted from the active layer into light of a predetermined wavelength band. (12) The light-emitting device according to (11), wherein the wavelength conversion layer includes a color conversion material. (13) The light-emitting device according to (11) or (12), having as the pixels a first pixel from which light in substantially the same wavelength band as the light emitted from the active layer is extracted and a second pixel from which light in a wavelength band different from the light emitted from the active layer is extracted, wherein the wavelength conversion layer provided in the first pixel includes a light-transmitting resin, and the wavelength conversion layer provided in the second pixel includes a color conversion material. (14) The light-emitting device according to any one of (11) to (13), further comprising a light-reflecting film that selectively reflects light in a predetermined wavelength band, having as the pixels a first pixel from which light in substantially the same wavelength band as the light emitted from the active layer is extracted and a second pixel from which light in a wavelength band different from the light emitted from the active layer is extracted, and the light-reflecting film is provided above the wavelength conversion layer provided in the second pixel. (15) The light-emitting device according to any one of (11) to (14), further comprising a light-absorbing film that selectively absorbs light of a predetermined wavelength band, the pixels including a first pixel from which light of substantially the same wavelength band as light emitted from the active layer is extracted and a second pixel from which light of a different wavelength band from the light emitted from the active layer is extracted, the light-absorbing film being provided above the wavelength conversion layer provided in the second pixel. (16) The light-emitting device according to any one of (1) to (15), further comprising a lens being provided above the second surface of the compound semiconductor layer.(17) An image display device comprising a light-emitting device, the light-emitting device comprising: a drive substrate; a compound semiconductor layer having a first surface facing the drive substrate and a second surface opposite to the first surface, and in which a first conductivity type layer, an active layer, and a second conductivity type layer are stacked in this order from the drive substrate side; a first separation groove provided from the first surface side and separating the first conductivity type layer and the active layer for each pixel; a second separation groove provided from the second surface side at a position facing the first separation groove and separating a part of the second conductivity type layer for each pixel; and a first metal film having light reflectivity provided along a side surface and a bottom surface of the second separation groove.

[0130] This application claims priority based on Japanese Patent Application No. 2023-215130, filed on December 20, 2023, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0131] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A light emitting device comprising: a drive substrate; a compound semiconductor layer having a first surface facing the drive substrate and a second surface opposite to the first surface, and in which a first conductivity type layer, an active layer, and a second conductivity type layer are laminated in this order from the drive substrate side; a first separation groove provided from the first surface side and separating the first conductivity type layer and the active layer for each pixel; a second separation groove provided from the second surface side at a position facing the first separation groove and separating a part of the second conductivity type layer for each pixel; and a first metal film having light reflectivity provided along the side and bottom surfaces of the second separation groove.

2. The light emitting device according to claim 1, wherein the first metal film also serves as wiring that electrically connects the drive substrate and the second conductive type layer.

3. The light emitting device according to claim 1, further comprising a second metal film, said second metal film including a metal material having optical reflectivity provided along the side surface and bottom surface of said first separation groove.

4. The light emitting device according to claim 1, wherein the first metal film contains at least one of aluminum and silver.

5. The light emitting device according to claim 3, wherein the second metal film contains at least one of aluminum and silver.

6. The light-emitting device according to claim 1, wherein the compound semiconductor layer further includes an undoped semiconductor layer and a buffer layer, and the undoped semiconductor layer and the buffer layer are stacked in this order on the second conductive type layer.

7. The light emitting device according to claim 1, wherein the first isolation groove is filled with the first metal film.

8. The light emitting device according to claim 1, wherein the width of the bottom surface of the first separation groove is wider than the width of the bottom surface of the second separation groove.

9. The light emitting device according to claim 1, wherein the side surface of the second separation groove is inclined at an angle of 90° or less.

10. The light emitting device according to claim 1, wherein the second conductive type layer is continuous between the pixels.

11. The light emitting device according to claim 1, further comprising a wavelength conversion layer provided above the second surface of the compound semiconductor layer and converting light emitted from the active layer into light of a predetermined wavelength band.

12. The light emitting device of claim 11, wherein the wavelength conversion layer comprises a color conversion material.

13. A light emitting device as described in claim 11, comprising as the pixels a first pixel from which light in approximately the same wavelength band as the light emitted from the active layer is extracted and a second pixel from which light in a different wavelength band from the light emitted from the active layer is extracted, the wavelength conversion layer provided in the first pixel includes a resin having optical transparency, and the wavelength conversion layer provided in the second pixel includes a color conversion material.

14. The light-emitting device according to claim 11, further comprising a light-reflecting film that selectively reflects light of a predetermined wavelength band, the pixels being a first pixel from which light of approximately the same wavelength band as the light emitted from the active layer is extracted, and a second pixel from which light of a different wavelength band than the light emitted from the active layer is extracted, the light-reflecting film being provided above the wavelength conversion layer provided in the second pixel.

15. The light-emitting device according to claim 11, further comprising a light-absorbing film that selectively absorbs light in a predetermined wavelength band, the pixels being a first pixel from which light in approximately the same wavelength band as the light emitted from the active layer is extracted, and a second pixel from which light in a different wavelength band from the light emitted from the active layer is extracted, the light-absorbing film being provided above the wavelength conversion layer provided in the second pixel.

16. The light emitting device according to claim 1, further comprising a lens, said lens being provided above said second surface of said compound semiconductor layer.

17. An image display device comprising a light-emitting device comprising: a drive substrate; a compound semiconductor layer having a first surface facing the drive substrate and a second surface opposite to the first surface, and in which a first conductivity type layer, an active layer and a second conductivity type layer are stacked in this order from the drive substrate side; a first separation groove provided from the first surface side and separating the first conductivity type layer and the active layer for each pixel; a second separation groove provided from the second surface side at a position facing the first separation groove and separating a part of the second conductivity type layer for each pixel; and a first metal film having light reflectivity provided along the side and bottom surfaces of the second separation groove.

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