Light-emitting device and image display device

Abstract

A light-emitting device according to one embodiment of the present disclosure comprises a plurality of light-emitting elements, wherein each of the plurality of light-emitting elements has a compound semiconductor layer in which a first conductivity type semiconductor layer, an active layer that produces emission light, and a second conductivity type semiconductor layer are layered in order in a first direction, and at least one of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer has a current constriction section including a current injection region through which a current can pass and a current constriction region that surrounds the current injection region. The current injection region in at least one of the plurality of light-emitting elements is provided in a location other than a location that overlaps, in the first direction, with a center location of the light-emitting element in an in-plane direction which is perpendicular to the first direction.

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 a light-emitting structure array system including at least one microlens in which the central axis of the light-emitting mesa and the central axis of the microlens are not coaxially aligned.

[0003] Japanese Patent Translation of PCT International Publication No. 2023-542832

[0004] By the way, in a light-emitting device using a micro LED (Light Emitting Diode), when correcting the light emitted from the light-emitting element, a decrease in light extraction efficiency has become a problem.

[0005] It is desirable to provide a light-emitting device that achieves both light distribution correction and maintenance of light-emitting efficiency, and an image display device including the same.

[0006] The light-emitting device according to one embodiment of the present disclosure includes a plurality of light-emitting elements. Each of the plurality of light-emitting elements has a compound semiconductor layer in which a first-conductivity-type semiconductor layer, an active layer that emits output light, and a second-conductivity-type semiconductor layer are sequentially stacked in a first direction. At least one of the first-conductivity-type semiconductor layer and the second-conductivity-type semiconductor layer has a current constriction portion including a current injection region through which current can pass and a current constriction region surrounding the current injection region. The current injection region in at least one of the plurality of light-emitting elements is provided at a position other than a position overlapping the central position of the light-emitting element in the in-plane direction orthogonal to the first direction and a position overlapping the first direction.

[0007] The image display device according to one embodiment of the present disclosure includes a light-emitting device, and the light-emitting device has the light-emitting device according to one embodiment of the present disclosure described above.

[0008] In the light-emitting device according to one embodiment of the present disclosure and the image display device according to one embodiment, the light-emitting position and the main optical axis direction of the light-emitting element are determined by the current injection region of the current constriction portion provided at a position other than the position overlapping the central position of the light-emitting element in the first direction.

[0009] Figure 1 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device according to one embodiment of the present disclosure. Figure 2 is a schematic plan view showing an example of the configuration of the light-emitting device shown in Figure 1. Figure 3 is a schematic plan view showing an example of the configuration of the current constriction section, transparent electrode layer, and wiring layer shown in Figure 1. Figure 4A is a schematic cross-sectional view illustrating an example of the manufacturing process of the light-emitting element shown in Figure 1. Figure 4B is a schematic cross-sectional view showing the process following Figure 4A. Figure 4C is a schematic cross-sectional view showing the process following Figure 4B. Figure 4D is a schematic cross-sectional view showing the process following Figure 4C. Figure 4E is a schematic cross-sectional view showing the process following Figure 4D. Figure 4F is a schematic cross-sectional view showing the process following Figure 4E. Figure 5A is a schematic cross-sectional view showing an example of a light-emitting device according to Modification 1 of the present disclosure. Figure 5B is a schematic cross-sectional view showing another example of a light-emitting device according to Modification 1 of the present disclosure. Figure 6 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device according to Modification 2 of the present disclosure. Figure 7 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device according to Modification 3 of the present disclosure. Figure 8 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device according to Modification 4 of the present disclosure. Figure 9A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device according to Modification 5 of the present disclosure. Figure 9B is a schematic plan view showing an example of the configuration of the current constriction section, transparent electrode layer, and wiring layer shown in Figure 9A. Figure 10A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device according to Modification 6 of the present disclosure. Figure 10B is a schematic plan view showing an example of the configuration of the current constriction section, transparent electrode layer, and wiring layer shown in Figure 10A. Figure 11A is a schematic plan view showing an example of the configuration of a light-emitting device according to Modification 7 of the present disclosure. Figure 11B is a schematic plan view showing another example of the configuration of a light-emitting device according to Modification 7 of the present disclosure. Figure 12 is a perspective view showing an example of the configuration of an image display device according to an application example of the present disclosure. Figure 13 is a schematic view showing an example of the wiring layout of the image display device shown in Figure 12. Figure 14 is a perspective view showing an example of the configuration of an image display device according to an application example of the present disclosure. Figure 15 is a perspective view showing the configuration of the mounting substrate shown in Figure 14. Figure 16 is a perspective view showing the configuration of the unit substrate shown in Figure 15. Figure 17 is a diagram showing an example of an image display device according to an application example of the present disclosure.

[0010] Hereinafter, one 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 each component shown in each figure. The order of description is as follows: 1. Embodiment (Example of a light-emitting device including a light-emitting element in which the center position and the current injection area of ​​the current constriction are offset) 1-1. Configuration of the light-emitting device 1-2. Method for manufacturing the light-emitting element 1-3. Operation and effect 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) 3. Application example (Example of an image display device)

[0011] <1. Embodiments> Figure 1 schematically shows an example of the cross-sectional configuration of a light-emitting device (light-emitting device 1) according to an embodiment of the present disclosure. Figure 2 schematically shows an example of the planar configuration of the light-emitting device 1 shown in Figure 1. The light-emitting device 1 is suitably applicable to an image display device called a so-called LED display (for example, the image display device 100 shown in Figure 12, which will be described later).

[0012] [1-1. Configuration of the Light-Emitting Device] The light-emitting device 1 has a stacked structure in which a support portion 30, a plurality of light-emitting elements 10, and a plurality of lenses 21 are stacked in order in the Z-axis direction, which is the thickness direction perpendicular to the XY plane, as shown in Figure 1, for example. In the light-emitting device 1, a plurality of pixels P are arranged in a two-dimensional array along the XY plane, which includes the mutually orthogonal X-axis and Y-axis directions, as shown in Figure 2, for example. Each of the plurality of pixels P is provided with, for example, one light-emitting element 10 and one lens 21. However, a plurality of light-emitting elements 10 may be provided for a single pixel P. Or, a plurality of lenses 21 may be provided for a single pixel P.

[0013] Each of the multiple light-emitting elements 10 has a compound semiconductor layer 11, a light-reflecting layer 131, a contact layer 132, a transparent electrode layer 14, a plug electrode 15, a pad electrode 16, a wiring layer 17, an insulating layer 181, and an insulating layer 182.

[0014] The light-emitting element 10 is a solid-state light-emitting element that emits light in a predetermined wavelength band from its upper surface, and is, for example, an LED (Light Emitting Diode) chip. An LED chip refers to an LED that has been cut from a wafer used for crystal growth, and is not a package type covered with molded resin or the like. The LED chip is, for example, 100 μm or less in size, and is what is known as a microLED.

[0015] The compound semiconductor layer 11 is constructed by sequentially stacking a first conductivity type semiconductor layer 111, an active layer 112 that emits emitted light L, and a second conductivity type semiconductor layer 113 in the Z-axis direction, starting from the support portion 30 side.

[0016] The first conductivity semiconductor layer 111 is formed of, for example, an n-type GaN-based semiconductor material. The active layer 112 has a multiple quantum well structure in which, for example, InGaN and GaN are alternately stacked, and has an emission region within the layer. From the active layer 112, for example, light L in the blue band between 430 nm and 500 nm is extracted. From the active layer 112, for example, light with a wavelength corresponding to the ultraviolet region (ultraviolet light) may be extracted. The second conductivity semiconductor layer 113 is formed of, for example, a p-type GaN-based semiconductor material. In the compound semiconductor layer 11, the upper surface of the second conductivity semiconductor layer 113, that is, the surface opposite to the active layer 112, is the light emission surface 11S1 of the compound semiconductor layer 11.

[0017] At least one of the first conductivity type semiconductor layer 111 and the second conductivity type semiconductor layer 113 has a current-constricting portion 12. However, Figure 1 illustrates the case where the current-constricting portion 12 is provided on the second conductivity type semiconductor layer 113. The current-constricting portion 12 imparts a constricting effect to the current flowing through the compound semiconductor layer 11.

[0018] The current-constricted region 12 includes a current-injection region 121 through which current can pass, and a current-constricted region 122 provided around the current-injection region 121. The current-constricted region 122 is embedded in the second conductivity type semiconductor layer 113 and exposed to the light-emitting surface 11S1 of the compound semiconductor layer 11, as shown in Figure 1, for example. The current-constricted region 122 is provided to continuously surround the current-injection region 121, as shown in Figure 2, for example. The current-constricted region 122 is a region through which current is less likely to flow than the current-injection region 121. For example, the ion concentration of the current-constricted region 122 is different from the ion concentration of the current-injection region 121. The current-constricted region 122 can be formed, for example, by injecting impurities from the light-emitting surface 11S1 of the compound semiconductor layer 11.

[0019] In the light-emitting device 1, the current injection region 121 in at least one of the multiple light-emitting elements 10 is located at a position other than one that overlaps with the center position (point O) of the light-emitting element 10 in the in-plane direction perpendicular to the Z-axis direction. The amount of offset between the center position of the current injection region 121 and the center position (point O) of the light-emitting element 10 is adjusted for each pixel P. For example, when considering that the 25 pixels P shown in Figure 2 constitute one light-emitting region, the amount of offset between the center position of the current injection region 121 and point O in pixels P close to the outer edge of the light-emitting region is greater than the amount of offset between the center position of the current injection region 121 and point O in pixels P close to the center of the light-emitting region. In other words, the current injection region 121 in pixels P close to the outer edge of the light-emitting region is located closer to the outer edge of the light-emitting region than the center position (point O) of the light-emitting element 10 in a plan view.

[0020] The light-reflecting layer 131 is provided between the compound semiconductor layer 11 and the insulating layer 181. The light-reflecting layer 131 is provided in the region occupied by the support portion 30, excluding the region that overlaps with the contact layer 132 in the Z-axis direction. The light-reflecting layer 131 is formed using a light-reflecting metal, dielectric material, or a multilayer film made by stacking these materials. Examples of metals used in the light-reflecting layer 131 include titanium (Ti), aluminum (Al), and silver (Ag).

[0021] The contact layer 132 is electrically connected to the pad electrode 16 via the plug electrode 15. The contact layer 132 is in ohmic contact with, for example, the first conductivity type semiconductor layer 111. The contact layer 132 is formed using, for example, a transparent conductive material such as a multilayer film of nickel (Ni) and gold (Au) (Ni / Au) or ITO. The contact layer 132 may also be composed of a metal such as Ti, TiN, TaN, Al, Ag, or a multilayer film of these metals.

[0022] The transparent electrode layer 14 is provided to continuously cover the light-emitting surface 11S1 of the compound semiconductor layer 11 and at least a portion of the side surface of the compound semiconductor layer 11. The transparent electrode layer 14 is in ohmic contact with the current injection region 121. The transparent electrode layer 14 penetrates the light-reflecting layer 131 and electrically connects the wiring layer 17 and the compound semiconductor layer 11. The transparent electrode layer 14 is formed from a transparent electrode material such as ITO, indium zinc oxide (IZO), tin oxide (SnO), or TiO.

[0023] Figure 3 schematically shows an example of the planar configuration of the current constriction section 12, transparent electrode layer 14, and wiring layer 17 shown in Figure 1. The transparent electrode layer 14 is provided continuously from the current constriction section 12 to the wiring layer 17 so as to cover the entire current constriction section 12 in a plan view and also be in contact with the wiring layer 17.

[0024] The plug electrode 15 and via 15V are electrically connected to the contact layer 132. The plug electrode 15 and via 15V are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof.

[0025] The pad electrode 16 is for electrically connecting the plug electrode 15 or wiring layer 17 to the support portion 30. The pad electrode 16 is formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or an alloy thereof.

[0026] The wiring layer 17 and the vias that electrically connect each wiring layer are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof.

[0027] The insulating layer 181 has the plug electrode 15, pad electrode 16, and wiring layer 17 embedded within it. The insulating layer 181 is formed of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0028] The insulating layer 182 is for flattening the surfaces of the compound semiconductor layer 11 and the transparent electrode layer 14 that face the lens 21. The insulating layer 182 is formed of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0029] Multiple lenses 21 are provided at corresponding positions on multiple light-emitting elements 10. The lenses 21 are for focusing or diverging the light L emitted from the compound semiconductor layer 11. Each of the multiple lenses 21 is made of a light-transmitting material. Each of the multiple lenses 21 is formed using, for example, at least one of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiCN), and resin.

[0030] Each of the multiple lenses 21 has an optical axis 21A. The optical axis 21A of each of the multiple lenses 21 coincides, for example, with the center position (point O) of the corresponding light-emitting element 10 in the Z-axis direction. Furthermore, as shown in Figure 1, for example, the current constriction region 122 in at least one of the multiple light-emitting elements 10 is located at a position other than the position that overlaps with the optical axis 21A of the corresponding lens 21 in the Z-axis direction.

[0031] The support portion 30 includes, for example, a support layer 31 and a plurality of pad portions 32 embedded in the support layer 31. The support layer 31 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN). Each of the plurality of pad portions 32 is electrically connected to the pad electrode 16. Each of the plurality of pad portions 32 is made of, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or an alloy thereof.

[0032] [1-2. Method for Manufacturing a Light-Emitting Device] The light-emitting device 1 of this embodiment can be manufactured, for example, as follows. Figures 4A to 4F show an example of the manufacturing process for the light-emitting device 10.

[0033] First, a sapphire substrate (not shown in the diagram) is prepared as a growth substrate. Then, for example, a first conductivity type semiconductor layer 111, an active layer 112, and a second conductivity type semiconductor layer 113 are sequentially formed on the growth substrate by epitaxial crystal growth using methods such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). Through these operations, a compound semiconductor layer 11 is obtained.

[0034] Next, a light-reflecting layer 131 with a contact layer 132 embedded is formed on an insulating layer 181 in which the plug electrode 15, pad electrode 16, and wiring layer 17 are embedded. At this time, the via 15V of the plug electrode 15 is made to join with the contact layer 132. Subsequently, as shown in Figure 4A, the compound semiconductor layer 11 is bonded to the light-reflecting layer 131 so that the light-reflecting layer 131 and the first conductivity type semiconductor layer 111 face each other.

[0035] Next, as shown in Figure 4B, the compound semiconductor layer 11 is cleaved, for example, by reactive ion etching (RIE) to form a mesa shape.

[0036] Next, as shown in Figure 4C, a resist R1 is formed on a portion of the upper surface of the second conductivity semiconductor layer 113. Subsequently, as shown in Figure 4D, the resist R1 is used as a mask to control the impurity concentration of the second conductivity semiconductor layer 113 exposed from the resist R1, for example by ion implantation, to form a current constriction region 12. After that, the resist R1 is removed.

[0037] Next, as shown in Figure 4E, a transparent electrode layer 14 is formed so as to be in contact with the upper surface of the second conductive semiconductor layer 113, at least a portion of the side surface of the compound semiconductor layer 11, and a portion of the wiring layer 17.

[0038] Next, an insulating layer 182 is formed to cover the compound semiconductor layer 11 and the transparent electrode layer 14. Then, as shown in Figure 4F, the lens 21 is bonded onto the insulating layer 182. With these steps, the light-emitting device 1 shown in Figure 1 is completed.

[0039] [1-3. Operation and Effects] The light-emitting device 1 of this embodiment comprises a plurality of light-emitting elements 10, each of which has a compound semiconductor layer 11 in which a first conductivity type semiconductor layer 111, an active layer 112, and a second conductivity type semiconductor layer 113 are sequentially stacked in the Z-axis direction. Furthermore, in the light-emitting element 10, at least one of the first conductivity type semiconductor layer 111 and the second conductivity type semiconductor layer 113 has a current-constricting portion 12 which includes a current injection region 121 through which current can pass and a current-constricting region 122 surrounding the current injection region 121. The current injection region 121 in at least one of the plurality of light-emitting elements 10 is provided at a position other than the position that overlaps with the center position point O of the light-emitting element in the Z-axis direction in the XY plane. As a result, the current injection region 121 of the current-constricting portion 12 provided at a position other than the position that overlaps with point O of the light-emitting element 10 in the Z-axis direction determines the light-emitting position and the direction of the principal optical axis of the light-emitting element 10. This will be explained below.

[0040] For example, in AR (Augmented Reality) and VR (Virtual Reality) applications, the size of the image display area of ​​a light-emitting device differs from the size of the light-emitting area of ​​the light-emitting element. In this case, a common problem with light-emitting devices is that the principal optical axis directions of the multiple light-emitting elements included in the device are uniform, resulting in reduced light extraction efficiency.

[0041] In light-emitting devices used for AR and VR applications, one method for changing the direction of the main optical axis of the light-emitting element to an arbitrary direction is to narrow the pitch of the lens provided on the light-emitting surface side of the light-emitting element compared to the light-emitting surface of the light-emitting element, and to offset the lens from the light-emitting element. However, with the above method, a reduction in light extraction efficiency remains a problem because the lens pitch becomes narrower. Furthermore, since the position of the light-emitting element needs to be adjusted to adjust the amount of offset, a design change is required for the junction surface between the drive substrate and the light-emitting element.

[0042] In contrast, in the light-emitting device 1 of the present embodiment, a current constriction portion 12 including a current injection region 121 provided at a position other than the position overlapping with the center position point O of the light-emitting element 10 in the Z-axis direction is provided. By adjusting the position of the current injection region 121 with respect to the active layer 112, the light-emitting position and the major optical axis direction of the light-emitting element 10 are determined. In the AR and VR applications, the light-emitting device 1 does not need to narrow the pitch of the lens 21 as in the above-described light-emitting device, so the light extraction efficiency is maintained. Further, since the light-emitting device 1 does not need to adjust the offset amount between the lens 21 and the light-emitting element 10 or change the design of the bonding surface with the support portion 30, the major optical axis direction can be easily controlled.

[0043] <2. Modified Example> Next, Modified Examples 1 to 7 and Application Examples of the present disclosure will be described. Note that the components corresponding to those of the light-emitting device 1 in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0044] [2-1. Modified Example 1] FIG. 5A schematically shows an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1A-1) according to Modified Example 1 of the present disclosure. FIG. 5B schematically shows an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1A-2) according to Modified Example 1 of the present disclosure.

[0045] In the above-described embodiment, an example in which the point O at the center position in at least one of the plurality of light-emitting elements 10 coincides with the optical axis 21A of the corresponding lens 21 in the Z-axis direction is shown, but the present disclosure is not limited thereto. In the light-emitting devices 1A-1 and 1A-2 of the present modified example, the point O at the center position in at least one of the plurality of light-emitting elements 10 is different from the position of the optical axis 21A of the corresponding lens 21 in the Z-axis direction. Further, as shown in FIG. 5B, in the light-emitting device 1A-2 of the present modified example, the current injection region 121 in at least one of the plurality of light-emitting elements 10 may be provided at a position other than the position overlapping with the optical axis 21A of the corresponding lens 21 in the Z-axis direction.

[0046] Except for the above points, the configurations of the light-emitting devices 1A-1 and 1A-2 are substantially the same as the configuration of the light-emitting device 1 in the above embodiment. Even in such a configuration, the light-emitting devices 1A-1 and 1A-2 can obtain the same effects as those in the above embodiment.

[0047] [2-2. Modified Example 2] Fig. 6 schematically shows an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1B) according to a modified example 2 of the present disclosure.

[0048] In the above embodiment, an example in which the current constriction portion 12 is formed in the second-conductive-type semiconductor layer 113 has been shown, but the present disclosure is not limited to this. In the light-emitting device 1E of this modified example, as shown in Fig. 6, a current constriction portion 12b is provided in the first-conductive-type semiconductor layer 111. The current constriction portion 12b includes a current injection region 121b through which current can pass and a current constriction region 122b provided around the current injection region 121b.

[0049] Except for the above points, the configuration of the light-emitting device 1B is substantially the same as the configuration of the light-emitting device 1 in the above embodiment. Even in such a configuration, the light-emitting device 1B can obtain the same effects as those in the above embodiment.

[0050] [2-3. Modified Example 3] Fig. 7 schematically shows an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1C) according to a modified example 3 of the present disclosure.

[0051] In the above embodiment, an example in which the impurity concentration of the current injection region 121 is different from the impurity concentration of the current constriction region 122 has been shown, but the present disclosure is not limited to this. Like the light-emitting device 1C of this modified example, the current constriction region 122c of the current constriction portion 12c may be embedded by the insulating layer 182. The current constriction region 122c can be obtained by forming a cavity by selectively removing a part of the second-conductive-type semiconductor layer 113 by, for example, dry etching in the manufacturing process and then embedding it with the insulating layer 182.

[0052] Except for the above points, the configuration of the light-emitting device 1C is substantially the same as the configuration of the light-emitting device 1 in the above embodiment. Even in such a configuration, the light-emitting device 1C can obtain the same effects as those in the above embodiment.

[0053] [2-4. Modification 4] Figure 8 schematically shows an example of the cross-sectional configuration of a light-emitting device (light-emitting device 1D) according to Modification 4 of the present disclosure.

[0054] In the above embodiment, an example was shown in which the compound semiconductor layer 11 and the lens 21 are composed of different materials, but the disclosure is not limited thereto. In the modified light-emitting device 1D, the lens 21d is continuous with the compound semiconductor layer 11 and is composed of the same material as the compound semiconductor layer 11. The lens 21d penetrates the transparent electrode layer 14. The current constriction portion 12 is provided in the first conductivity type semiconductor layer 111, similar to the modified example 2.

[0055] Except for the points mentioned above, the configuration of the light-emitting device 1D is substantially the same as the configuration of the light-emitting device 1 in the above embodiment. Even with such a configuration, the light-emitting device 1D can obtain the same effects as in the above embodiment.

[0056] [2-5. Modification 5] Figure 9A schematically shows an example of the cross-sectional configuration of the light-emitting device (light-emitting device 1E) according to Modification 5 of the present disclosure. Figure 9B schematically shows an example of the planar configuration of the current constriction portion 12e, transparent electrode layer 14e, and wiring layer 17 shown in Figure 9A.

[0057] In the above embodiment, an example was shown in which the impurity concentration in the current injection region 121 and the impurity concentration in the current constriction region 122 are different, but this disclosure is not limited thereto. In this modified light-emitting device 1E, similar to the light-emitting device 1C of modified example 3, the current constriction region 122e of the current constriction portion 12e may be embedded by an insulating layer 182. The current constriction region 122e can be obtained by forming a cavity by selectively removing a part of the second conductivity type semiconductor layer 113, for example by dry etching, during the manufacturing process, and then filling it with an insulating layer 182.

[0058] Furthermore, in the above embodiment, an example was shown in which the transparent electrode layer 14 is provided to continuously cover the light-emitting surface 11S1 of the compound semiconductor layer 11 and at least one of the side surfaces of the compound semiconductor layer 11, but the present disclosure is not limited thereto. In the light-emitting device 1E of this modified example, as shown in Figures 9A and 9B, the transparent electrode layer 14e is provided to continuously cover the upper surface of the current injection region 121 of the light-emitting surface 11S1 of the compound semiconductor layer 11 and at least one of the side surfaces of the compound semiconductor layer 11.

[0059] Except for the points mentioned above, the configuration of the light-emitting device 1E is substantially the same as the configuration of the light-emitting device 1 in the above embodiment. Even with this configuration, the light-emitting device 1E can obtain the same effects as in the above embodiment.

[0060] [2-6. Modification 6] Figure 10A schematically shows an example of the cross-sectional configuration of the light-emitting device (light-emitting device 1F) according to Modification 6 of the present disclosure. Figure 10B schematically shows an example of the planar configuration of the current constriction section 12, transparent electrode layer 14, and wiring layer 17 shown in Figure 10A.

[0061] In the above embodiment, an example was shown in which the compound semiconductor layers 11 of multiple light-emitting elements 10 are separated, but the disclosure is not limited thereto. In the modified light-emitting device 1F, as shown in Figures 10A and 10B, the multiple light-emitting elements 10 share a single continuous first conductivity type semiconductor layer 111f with each other.

[0062] Except for the points mentioned above, the configuration of the light-emitting device 1F is substantially the same as the configuration of the light-emitting device 1 in the above embodiment. Even with this configuration, the light-emitting device 1F can obtain the same effects as in the above embodiment.

[0063] [2-7. Modification 7] Figure 11A schematically shows an example of the planar configuration of a light-emitting device (light-emitting device 1G-1) according to Modification 7 of the present disclosure. Figure 11B schematically shows another example of the planar configuration of a light-emitting device (light-emitting device 1G-2) according to Modification 7 of the present disclosure shown in Figure 11A.

[0064] In the above embodiment, an example was shown in which the current injection region 121 of a pixel P closer to the outer periphery of the light-emitting region composed of multiple pixels P is located closer to the outer periphery of the light-emitting region than point O of the pixel P in a plan view. However, this disclosure is not limited to this. In the modified light-emitting device 1G-1, as shown in Figure 11A, the current injection region 121 of a pixel P closer to the outer periphery of the light-emitting region composed of multiple pixels P is located closer to the center of the light-emitting region than point O of the pixel P in a plan view. Furthermore, this disclosure is not limited to the case where the shape of the light-emitting region is rectangular in a plan view. The shape of the light-emitting region composed of multiple pixels P may be substantially trapezoidal in a plan view, as in the light-emitting device 1G-2 shown in Figure 11B. In the light-emitting device 1G-2 of Figure 11B, the current injection regions 121 of the multiple pixels P may be located along the outer edge of the light-emitting region which is substantially trapezoidal in a plan view. According to the modified light-emitting device 1G-2, for example, when used as a light source for an image projection device, optical distortion can be added in advance to cancel out the optical image distortion that occurs in the projection optical system mounted on the image projection device.

[0065] Except for the points mentioned above, the configurations of the light-emitting devices 1G-1 and 1G-2 are substantially the same as those of the light-emitting device 1 in the above embodiment. Even with such a configuration, the light-emitting devices 1G-1 and 1G-2 can obtain the same effects as in the above embodiment.

[0066] <3. Application Examples> (Application Example 1) Figure 12 is a perspective view showing an example of the 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 of this disclosure (for example, light-emitting device 1) is used as the display pixel. The image display device 100 includes, for example, a display panel 120 and a control circuit 140 that drives the display panel 120, as shown in Figure 12.

[0067] The display panel 120 consists of a mounting substrate 120A and an opposing substrate 120B superimposed on each other. The surface of the opposing substrate 120B serves as the image display surface, with a display area (display section 100A) in the center and a non-display area, the frame section 100B, surrounding it.

[0068] Figure 13 shows an example of the wiring layout of the area corresponding to the display unit 100A on the surface of the mounting substrate 120A on the opposing substrate 120B side. On the surface of the mounting substrate 120A, in the area 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 Figure 13. On the surface of the mounting substrate 120A, in the area corresponding to the display unit 100A, a plurality of scan wirings 135 are formed extending in a direction intersecting (for example, orthogonal) with the data wirings 134 and arranged in parallel at a predetermined pitch. The data wirings 134 and scan wirings 135 are made of a conductive material such as Cu.

[0069] The scan wiring 135 is formed, for example, on the outermost layer, and is formed 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 wiring 134 is formed in a layer different from the outermost layer containing the scan wiring 135 (for example, a layer below the outermost layer), and is formed, for example, in an insulating layer on the substrate.

[0070] The vicinity of the intersection of the data wiring 134 and the scan wiring 135 is a display pixel 136, and multiple display pixels 136 are arranged in a matrix within the display unit 100A. Each display pixel 136 is equipped with, for example, the respective color pixels Pr, Pg, and Pb of the light-emitting device 1.

[0071] The light-emitting device 1 is provided with terminal electrodes, for example, one pair for each color pixel Pr, Pg, and Pb, or one common electrode and the other arranged for each color pixel Pr, Pg, and Pb. One terminal electrode is electrically connected to the data wiring 134, and the other terminal electrode is electrically connected to the scan wiring 135. For example, one terminal electrode is electrically connected to the pad electrode 134B at the tip of a branch 134A provided on the data wiring 134. Also, for example, the other terminal electrode is electrically connected to the pad electrode 135B at the tip of a branch 135A provided on the scan wiring 135.

[0072] Each pad electrode 134B, 135B is formed, for example, on the outermost layer and is provided in the area where each light-emitting device 1 is mounted, as shown in Figure 13. Here, the pad electrodes 134B, 135B are made of a conductive material such as Au (gold).

[0073] The mounting substrate 120A is further provided with a plurality of support columns (not shown) that, for example, regulate the distance between the mounting substrate 120A and the opposing substrate 120B. The support columns may be provided in the area facing the display unit 100A, or in the area facing the frame unit 100B.

[0074] The opposing substrate 120B is made of, for example, a glass substrate or a resin substrate. On the opposing substrate 120B, the surface on the side facing the light-emitting device 1 may be flat, but it is preferable that it be rough. The rough surface may be provided over the entire area facing the display unit 100A, or it may be provided only in the area facing the display pixels 136. The rough surface has fine irregularities that allow light emitted from the color pixels Pr, Pg, and Pb to enter the rough surface. The irregularities of the rough surface can be created, for example, by sandblasting or dry etching.

[0075] The control circuit 140 drives each display pixel 136 (each light-emitting device 1) based on the video signal. The control circuit 140 is composed of, for example, a data driver that drives data wiring 134 connected to the display pixel 136 and a scan driver that drives scan wiring 135 connected to the display pixel 136. The control circuit 140 may be provided separately from the display panel 120 and connected to the mounting board 120A via wiring, as shown in Figure 13, or it may be mounted on the mounting board 120A.

[0076] (Application Example 2) Figure 14 is a perspective view showing another configuration example (image display device 200) of an image display device using the light-emitting device of this disclosure (for example, light-emitting device 1). The image display device 200 is a so-called tiling display that uses a plurality of light-emitting devices with LEDs as light sources. The image display device 200 includes, for example, a display panel 220 and a control circuit 240 that drives the display panel 220, as shown in Figure 14.

[0077] The display panel 220 consists of a mounting substrate 220A and an opposing substrate 220B superimposed on each other. The surface of the opposing substrate 220B serves as the image display surface, with a display area in the center and a frame area surrounding it, which is a non-display area (neither of which is shown). The opposing substrate 220B is positioned opposite the mounting substrate 220A, for example, with a predetermined gap between them. The opposing substrate 220B may also be in contact with the upper surface of the mounting substrate 220A.

[0078] Figure 15 schematically shows an example of the configuration of the mounting board 220A. The mounting board 220A is composed of multiple unit boards 250 arranged in a tile-like pattern, as shown in Figure 15. In Figure 15, an example is shown in which the mounting board 220A is composed of nine unit boards 250, but the number of unit boards 250 may be 10 or more, or 8 or less.

[0079] Figure 16 shows an example of the configuration of a unit board 250. The unit board 250 has, for example, a plurality of light-emitting devices 1 arranged in a tile-like pattern, and a support board 260 that supports each light-emitting device 1. Each unit board 250 further has a control board (not shown). The support board 260 is made of, for example, a metal frame (metal plate) or a wiring board. If the support board 260 is made of a wiring board, it can also serve as the control board. In this case, at least one of the support board 260 and the control board is electrically connected to each light-emitting device 1.

[0080] (Application Example 3) Figure 17 shows the appearance of the transparent display 300. The transparent display 300 includes, for example, a display unit 310, an operation unit 311, and a housing 312. The display unit 310 uses the light-emitting device of this disclosure (for example, light-emitting device 1). This transparent display 300 is capable of displaying images and text information while allowing the background of the display unit 310 to pass through.

[0081] In the transparent display 300, the mounting substrate is a light-transmitting substrate. Each electrode provided on the light-emitting device 1 is formed using a conductive material that is light-transmitting, similar to the mounting substrate. Alternatively, each electrode is designed to be difficult to see by reducing the width of the wiring or the thickness of the wiring. Furthermore, the transparent display 300 can display black by, for example, layering a liquid crystal layer equipped with a driving circuit, and switching between transmission and black display is possible by controlling the light distribution direction of the liquid crystal.

[0082] The present technology has been described above with reference to embodiments and modifications 1 to 7 and application examples. However, the present technology is not limited to the above embodiments, and various modifications are possible. For example, the above embodiments show examples in which the light emitted from the active layer 112 is blue light or ultraviolet light, but the technology is not limited to these. For example, the light-emitting device 1 can 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.

[0083] Furthermore, although the above embodiments have described the components constituting the light-emitting device 1, etc., it is not necessary to include all components, and other components may also be included.

[0084] Furthermore, although the above embodiments illustrate cases where the drive circuit and the like are provided outside the light-emitting device, this disclosure is not limited thereto. The light-emitting device 1 may, for example, have the drive circuit provided inside the support portion 30 and connect the drive circuit to the light-emitting element 10.

[0085] Furthermore, the effects described herein are merely examples and are not limited to those described; other effects may also occur.

[0086] The present technology can also take the following configuration. According to the present technology with the following configuration, the light emission position and the direction of the principal optical axis of the light-emitting element are determined by the current injection region of the current constriction portion provided at a position other than the central position of the light-emitting element and a position overlapping in the first direction. This makes it easier to control the light distribution while maintaining the light extraction efficiency. (1) A light-emitting device comprising a plurality of light-emitting elements, each of the plurality of light-emitting elements having a compound semiconductor layer in which a first conductivity type semiconductor layer, an active layer that emits emitted light, and a second conductivity type semiconductor layer are stacked in order in the first direction, at least one of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer has a current constriction portion including a current injection region through which current can pass and a current constriction region surrounding the current injection region, and the current injection region of at least one of the plurality of light-emitting elements is provided at a position other than the central position of the light-emitting element in an in-plane direction perpendicular to the first direction and a position overlapping in the first direction. (2) The light-emitting device according to (1) above, wherein the ion concentration of the current constriction region is different from the ion concentration of the current injection region. (3) The light-emitting device according to (1) or (2), wherein the current-constricting region is embedded by an insulating embedding layer. (4) The light-emitting device according to any one of (1) to (3), wherein the current-constricting region continuously surrounds the periphery of the current-injection region. (5) The light-emitting device according to any one of (1) to (4), further comprising a plurality of lenses provided at corresponding positions of the plurality of light-emitting elements for focusing or diverging the emitted light. (6) The light-emitting device according to (5), wherein the center position of at least one of the plurality of light-emitting elements coincides with the optical axis of the corresponding lens in the first direction. (7) The light-emitting device according to (5), wherein the center position of at least one of the plurality of light-emitting elements does not coincide with the optical axis of the corresponding lens in the first direction. (8) The light-emitting device according to any one of (5) to (7), wherein the current-injection region of at least one of the plurality of light-emitting elements is provided at a position other than one that overlaps with the optical axis of the corresponding lens in the first direction.(9) The light-emitting device according to any one of (5) to (8), wherein each of the plurality of lenses comprises at least one of silicon oxide, silicon nitride, silicon oxynitride, and resin. (10) The light-emitting device according to any one of (5) to (9), wherein each of the plurality of lenses is made of the same material as the compound semiconductor layer. (11) The light-emitting device according to any one of (1) to (10), wherein the plurality of light-emitting elements constitute a single light-emitting region, and each of the current injection regions of the plurality of light-emitting elements is located near the outer periphery of the light-emitting region in a plan view. (12) The light-emitting device according to any one of (1) to (11), wherein the plurality of light-emitting elements constitute a single light-emitting region, and each of the current injection regions of the plurality of light-emitting elements is located near the center of the light-emitting region in a plan view. (13) An image display device comprising a light-emitting device, wherein the light-emitting device includes a plurality of light-emitting elements, each of the plurality of light-emitting elements has a compound semiconductor layer in which a first conductivity type semiconductor layer, an active layer that emits emitted light, and a second conductivity type semiconductor layer are stacked in order in a first direction, and at least one of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer has a current-constricting portion including a current injection region through which current can pass and a current-constricting region surrounding the current injection region, and the current injection region of at least one of the plurality of light-emitting elements is provided at a position other than the center position of the light-emitting element in an in-plane direction perpendicular to the first direction and a position that overlaps with the first direction.

[0087] This application claims priority based on Japanese Patent Application No. 2024-191131, filed with the Japan Patent Office on 30 October 2024, and all contents of that application are incorporated herein by reference.

[0088] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A light-emitting device comprising a plurality of light-emitting elements, each of the plurality of light-emitting elements having a compound semiconductor layer in which a first conductivity type semiconductor layer, an active layer that emits emitted light, and a second conductivity type semiconductor layer are stacked in order in a first direction, at least one of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer having a current-constricting portion including a current injection region through which current can pass and a current-constricting region surrounding the current injection region, and the current injection region of at least one of the plurality of light-emitting elements being provided at a position other than the center position of the light-emitting element in an in-plane direction perpendicular to the first direction and a position that overlaps with the first direction.

2. The light-emitting device according to claim 1, wherein the ion concentration in the current-constricted region is different from the ion concentration in the current-injection region.

3. The light-emitting device according to claim 1, wherein the current-constricting region is embedded by an insulating embedding layer.

4. The light-emitting device according to claim 1, wherein the current-constricting region continuously surrounds the periphery of the current-injection region.

5. The light-emitting device according to claim 1, further comprising a plurality of lenses provided at corresponding positions of the plurality of light-emitting elements for focusing or diverging the emitted light.

6. The light-emitting device according to claim 5, wherein the central position of at least one of the plurality of light-emitting elements coincides with the optical axis of the corresponding lens in the first direction.

7. The light-emitting device according to claim 5, wherein the central position of at least one of the plurality of light-emitting elements is different from the position of the optical axis of the corresponding lens in the first direction.

8. The light-emitting device according to claim 5, wherein the current injection region in at least one of the plurality of light-emitting elements is provided at a position other than one that overlaps with the optical axis of the corresponding lens in the first direction.

9. The light-emitting device according to claim 5, wherein each of the plurality of lenses comprises at least one of silicon oxide, silicon nitride, silicon oxynitride, and resin.

10. The light-emitting device according to claim 5, wherein each of the plurality of lenses is made of the same material as the compound semiconductor layer.

11. The light-emitting device according to claim 1, wherein the plurality of light-emitting elements constitute a single light-emitting region, and each of the current injection regions of the plurality of light-emitting elements is provided along the outer edge of the light-emitting region in a plan view.

12. The light-emitting device according to claim 1, wherein the plurality of light-emitting elements constitute a single light-emitting region, and each of the current injection regions of the plurality of light-emitting elements is located closer to the center of the light-emitting region than the center of the light-emitting element in a plan view.

13. An image display device comprising a light-emitting device, wherein the light-emitting device includes a plurality of light-emitting elements, each of the plurality of light-emitting elements has a compound semiconductor layer in which a first conductivity type semiconductor layer, an active layer that emits emitted light, and a second conductivity type semiconductor layer are stacked in order in a first direction, at least one of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer has a current-constricting portion including a current injection region through which current can pass and a current-constricting region surrounding the current injection region, and the current injection region of at least one of the plurality of light-emitting elements is provided at a position other than the center position of the light-emitting element in an in-plane direction perpendicular to the first direction and a position that overlaps with the first direction.

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