Light-emitting element array

Abstract

A light-emitting element array according to one embodiment of the present disclosure comprises: a substrate that has a first surface and a second surface which face each other; a plurality of light-emitting elements that are arranged in a two-dimensional array form on the first surface with mutually differing spacing and that have mesa shapes; and recessed portions that are provided on the peripheries of the plurality of light-emitting elements, that form the mesa shapes, and that have depths which differ in accordance with the spacing between neighboring members of the plurality of light-emitting elements.

Description

[Technical Field]

[0001] The present disclosure relates to, for example, a light-emitting element array having a plurality of light-emitting elements randomly arranged in a plane. I Regarding. [Background technology]

[0002] For example, Patent Document 1 discloses a surface-emitting laser element in which a separation groove is provided at a position away from the mesa structure and reaches the substrate surface, the surface of the lower semiconductor BDR exposed by the separation groove is passivated, and further covered with a dielectric film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-132692 Summary of the Invention

[0004] Incidentally, when a light emitting element array is used as the light source of a distance measuring device, for example, uniform light emission within the plane is desired.

[0005] Light-emitting element array having substantially uniform light emission in the plane I It is desirable to provide

[0006] In one embodiment of the present disclosure 1st The light-emitting element array comprises a substrate having a first surface and a second surface facing each other, a plurality of light-emitting elements arranged in a two-dimensional array on the first surface at different intervals and having a mesa shape, and recesses provided around the plurality of light-emitting elements, forming a mesa shape, and having depths that vary according to the intervals between the plurality of adjacent light-emitting elements. The substrate further has an array section in which a plurality of light-emitting elements are arranged in a two-dimensional array, the array section having a plurality of regions, and the plurality of light-emitting elements are arranged at different intervals in each region. . A second light-emitting element array according to one embodiment of the present disclosure comprises a substrate having opposing first and second surfaces, a plurality of light-emitting elements arranged in a two-dimensional array on the first surface at different intervals and having a mesa shape, and recesses formed around the plurality of light-emitting elements, the recesses forming a mesa shape and having a depth that varies depending on the spacing between adjacent light-emitting elements, and the substrate further has an array portion in which the plurality of light-emitting elements are arranged in a two-dimensional array, and the plurality of light-emitting elements are arranged randomly in the array portion. A third light-emitting element array according to one embodiment of the present disclosure comprises a substrate having opposing first and second surfaces, a plurality of light-emitting elements arranged in a two-dimensional array on the first surface at different intervals and having a mesa shape, and a recess provided around the plurality of light-emitting elements to form a mesa shape and whose depth varies depending on the spacing between adjacent light-emitting elements. The light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, and further has a first contact layer provided between the first light-reflecting layer and the substrate, and a second contact layer on the surface of the second light-reflecting layer opposite the active layer. The recess has a first recess provided between adjacent light-emitting elements arranged at the first spacing and a second recess provided between adjacent light-emitting elements arranged at a second spacing wider than the first spacing, the first recess having a bottom surface within the first contact layer, and the second recess penetrating the first contact layer.A fourth light-emitting element array according to an embodiment of the present disclosure comprises a substrate having opposing first and second surfaces, a plurality of light-emitting elements arranged in a two-dimensional array on the first surface at different intervals and having a mesa shape, and a recess provided around the plurality of light-emitting elements to form a mesa shape and whose depth varies depending on the spacing between adjacent light-emitting elements. The light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, and further has a first contact layer provided between the first light-reflecting layer and the substrate, and a second contact layer on the surface of the second light-reflecting layer opposite the active layer. The recess has a first recess provided between adjacent light-emitting elements arranged at the first spacing and a second recess provided between adjacent light-emitting elements arranged at a second spacing wider than the first spacing. The first recess has a bottom surface within the first light-reflecting layer, and the second recess penetrates the first light-reflecting layer. A fifth light-emitting element array according to an embodiment of the present disclosure comprises a substrate having opposing first and second surfaces, a plurality of light-emitting elements arranged in a two-dimensional array on the first surface at different intervals and having a mesa shape, and a recess provided around the plurality of light-emitting elements, forming a mesa shape and having a depth that varies depending on the spacing between adjacent light-emitting elements. The light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, and further has a first contact layer provided between the first light-reflecting layer and the substrate, and a second contact layer on the surface of the second light-reflecting layer opposite the active layer, and is a surface-emitting surface-emitting laser that emits laser light from the second contact layer side, and further has a current diffusion adjustment layer between the substrate and the first contact layer or between the first contact layer and the first light-reflecting layer.

[0008] In one embodiment of the present disclosure 1st to 5th Light-emitting element array IIn the method, a plurality of compound semiconductor layers constituting the light-emitting element are sequentially stacked on a substrate, a resist layer having a pattern with different densities is formed on the compound semiconductor layer, and reactive ion etching is performed using the resist layer as a mask at a temperature of 80° C. or less. In this way, a plurality of light-emitting elements each having a mesa shape are formed in a two-dimensional array on the first surface at different intervals, and recesses having depths that vary according to the intervals between adjacent light-emitting elements are formed between adjacent light-emitting elements, thereby canceling out differences in electrical resistance caused by the arrangement density of the light-emitting elements. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a configuration of a light-emitting element array according to a first embodiment of the present disclosure. [Figure 2] 2 is a schematic plan view illustrating an example of the overall configuration of the light-emitting element array shown in FIG. 1. FIG. [Figure 3] 4 is a flowchart illustrating an example of a method for manufacturing the light-emitting element array shown in FIG. [Figure 4A] 4A to 4C are cross-sectional views illustrating a method for manufacturing the light-emitting element array shown in FIG. [Figure 4B] FIG. 4B is a schematic cross-sectional view showing the configuration subsequent to FIG. 4A. [Figure 4C] FIG. 4C is a schematic cross-sectional view showing the configuration subsequent to FIG. 4B. [Figure 4D] FIG. 4D is a schematic cross-sectional view showing the configuration subsequent to FIG. 4C. [Figure 4E] FIG. 4E is a schematic cross-sectional view showing the configuration subsequent to FIG. 4D. [Figure 4F] FIG. 4B is a schematic cross-sectional view showing the configuration subsequent to FIG. 4E. [Figure 4G] FIG. 4B is a schematic cross-sectional view showing the configuration subsequent to FIG. 4F. [Figure 4H] FIG. 4B is a schematic cross-sectional view showing the configuration subsequent to FIG. 4G. [Figure 5] 1A and 1B are schematic diagrams illustrating the spread of current in a typical light-emitting element array. [Figure 6] FIG. 10 is a cross-sectional view illustrating an example of a configuration of a light-emitting element array according to a second embodiment of the present disclosure. [Figure 7] 7 is a plan view schematically illustrating an example of the overall configuration of the light-emitting element array shown in FIG. 6. FIG. [Figure 8] 7 is a flowchart illustrating an example of a manufacturing method for the light-emitting element array shown in FIG. [Figure 9A] 9A to 9C are cross-sectional views illustrating a method for manufacturing the light-emitting element array shown in FIG. 8. [Figure 9B] FIG. 9B is a schematic cross-sectional view showing the configuration subsequent to FIG. 9A. [Figure 9C] FIG. 9C is a schematic cross-sectional view showing the configuration subsequent to FIG. 9B. [Figure 10] 7 is a schematic diagram illustrating the spread of current in the light-emitting element array shown in FIG. 6. FIG. [Figure 11] FIG. 10 is a cross-sectional view schematically illustrating an example of a configuration of a light-emitting element array according to a modified example of the present disclosure. [Figure 12] FIG. 10 is a cross-sectional view schematically illustrating another example of the configuration of a light-emitting element array according to a modified example of the present disclosure. [Figure 13] 2 is a block diagram showing an example of a schematic configuration of a distance measuring device using an illumination device equipped with the light-emitting element array shown in FIG. 1 etc. FIG. [Figure 14] 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; [Figure 15] FIG. 2 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description is one specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The order of description is as follows. 1. First embodiment (example of a rear-emission type light-emitting element array having recesses whose depths vary depending on the spacing between adjacent light-emitting elements) 2. Second embodiment (an example of a surface-emitting light-emitting element array having recesses whose depths vary depending on the spacing between adjacent light-emitting elements) 3. Modification (Example in which a current diffusion layer is further provided) 4. Application example (example of distance measuring device) 5. Application Examples

[0011] <1. First embodiment> Fig. 1 is a schematic diagram showing an example of a cross-sectional configuration of a light-emitting element array 1 according to a first embodiment of the present disclosure. Fig. 2 is a schematic diagram showing an example of a planar configuration of the entire light-emitting element array 1 shown in Fig. 1. Fig. 1 shows a cross section corresponding to line II' shown in Fig. 2. This light-emitting element array 1 is, for example, a two-dimensional array of back-emitting VCSELs (Vertical Cavity Surface Emitting LASERs).

[0012] [Configuration of light-emitting element array] The light-emitting element array 1 has, for example, a plurality of light-emitting elements 10 arranged on a surface 11S1 of a substrate having a first surface (surface 11S1) and a second surface (rear surface 11S2) facing each other. The light-emitting element array 1 has a light-emitting region R1 in which the plurality of light-emitting elements 10 are arranged in a two-dimensional array, and a peripheral region R2 provided on the outer periphery of the light-emitting region R1. This light-emitting region R1 corresponds to a specific example of an "array section" in the present disclosure.

[0013] Each of the plurality of light-emitting elements 10 has a mesa shape. The diameter (mesa diameter) of each light-emitting element 10 is slightly smaller than the minimum beam pitch of the laser light emitted from each light-emitting element 10. For example, if the minimum beam pitch is to be about 18 μm, the mesa diameter is set to about 14 μm.

[0014] In the light-emitting element array 1 of the present embodiment, the plurality of light-emitting elements 10 are arranged at different intervals from each other in the light-emitting region R1. For example, in the light-emitting region R1, as shown in FIG. 2, a first region R1-1 in which a plurality of light-emitting elements 10 are arranged at a first pitch l1 and a second region R1-2 in which a plurality of light-emitting elements 10 are arranged at a second pitch l2 are alternately arranged in the matrix direction. In addition, the plurality of light-emitting elements 10 may be randomly arranged so that the intervals between adjacent light-emitting elements 10 in the light-emitting region R1 are different without regularity.

[0015] Furthermore, the light-emitting element array 1 has recesses H each having a plurality of light-emitting elements 10 in a mesa shape. The recess H has different depths according to the intervals between adjacent plurality of light-emitting elements 10. For example, when the arrangement pitches (first pitch l1 and second pitch l2) of the plurality of light-emitting elements 10 arranged in the first region R1-1 and the second region R1-2 shown in FIG. 2 have a relationship of l1 < l2, the depth h1 of the recess H1 provided between adjacent light-emitting elements 10 in the first region R1-1 and the depth h2 of the recess H2 provided between adjacent light-emitting elements 10 in the second region R1-2 have a relationship of h1 < h2. That is, in the light-emitting element array 1 of the present embodiment, around the plurality of light-emitting elements 10 arranged at different intervals from each other, recesses H are formed such that the closer the interval between adjacent plurality of light-emitting elements 10, the shallower, and the wider the interval between adjacent plurality of light-emitting elements 10, the deeper.

[0016] The first pitch l1 and the second pitch l2 are each the distance between the centers of adjacent light-emitting elements 10 in the first region R1-1 and the second region R1-2.

[0017] [Configuration of Light-Emitting Element] The light-emitting elements 10 are VCSELs that emit laser light in the stacking direction. Each of the light-emitting elements 10 includes, for example, a first DBR (Distributed Bragg Reflector) layer 13 including a current-confining layer 19 therein, a first spacer layer 14, an active layer 15, a second spacer layer 16, and a second DBR layer 17 stacked in this order. A first contact layer 12 is provided between the light-emitting elements 10 and the substrate 11. A second contact layer 18 is provided on each of the upper surfaces 10S1 of the light-emitting elements 10. A first electrode 21 is provided between adjacent light-emitting elements 10, i.e., on the bottom surfaces of recesses H (recesses H1, H2) provided around the light-emitting elements 10. A second electrode 22 is provided on each of the second contact layers 18 provided on the upper surfaces 10S1 of the light-emitting elements 10. Furthermore, the upper surface of the first contact layer 12, excluding the areas where the first electrode 21 and the second electrode 22 are formed, the side surfaces of the multiple light-emitting elements 10, and the side surfaces and upper surface of the second contact layer 18 are covered with an insulating film 23, and the rear surface 11S2 of the substrate 11 is covered with an anti-reflection film 24.

[0018] The configuration and materials of each part of the light-emitting element array 1 will be described in detail below.

[0019] The substrate 11 is a support substrate on which the plurality of light-emitting elements 10 are integrated. The substrate 11 is made of a semi-insulating substrate that transmits light emitted from the plurality of light-emitting elements 10. An example of a semi-insulating substrate is a substrate that does not contain impurities, such as a substrate made of a GaAs-based semiconductor. The substrate 11 is not necessarily limited to a general semi-insulating substrate as long as it has a low carrier concentration and reduces absorption of laser light. For example, the substrate 11 may be a substrate having an n-type carrier concentration of 5×10 17 cm -3 Substrates with the following carrier concentrations can be used:

[0020] The first contact layer 12 is for making the first electrode 21 in ohmic contact with the first DBR layer 13 of each light-emitting element 10. The first contact layer 12 is formed continuously on the surface 11S1 of the substrate 11 as a common layer for, for example, a plurality of light-emitting elements 10. The first contact layer 12 is made of, for example, n-type Al X1 Ga 1-X1 As (0 ≦ X1 < 1).

[0021] The first DBR layer 13 is made of, for example, an n-type semiconductor material. The first DBR layer 13 faces the second DBR layer 17 with the active layer 15 in between, and constitutes a resonator for resonating the light with wavelength λ generated in the active layer 15 between it and the second DBR layer 17 to cause laser oscillation. The first DBR layer 13 has a structure in which a low refractive index layer (not shown) and a high refractive index layer (not shown) are alternately laminated. The low refractive index layer is made of, for example, n-type Al X2 Ga 1-X2 As (0 < X2 ≦ 1) with an optical film thickness of λ×1 / 4n, and the high refractive index layer is made of, for example, n-type Al X3 Ga 1-X3 As (0 ≦ X3 < X2). λ is the oscillation wavelength of the laser light emitted from the active layer 15, and n is the refractive index.

[0022] The current confinement layer 19 imparts a current confinement effect and is provided within the layer of the first DBR layer 13. The current confinement layer 19 has a current injection region 19A and a current confinement region 19B. The current injection region 19A is provided at the center of the current confinement layer 19, and the current confinement region 19B is provided around the current injection region 19A. The current injection region 19A is made of a conductive material, and the current confinement region 19B is made of an insulating material. The current confinement region 19B can be formed by oxidizing from the side surface of the light-emitting element 10 having the material constituting the current confinement layer 19. The current injection region 19A is, for example, n-type Al X4 Ga 1-X4It consists of As(0 < X4 ≤ 1), and the current constriction region 19B is made of, for example, its oxide. In the light-emitting element array 1, by providing this current constriction layer 19, the current injected from the first electrode 21 into the active layer 15 is constricted, and the current injection efficiency is enhanced.

[0023] The first spacer layer 14 adjusts the distance between the first DBR layer 13 and the second DBR layer 17 to be λ. The first spacer layer 14 is made of, for example, n-type Al X5 Ga 1-X5 As(0 ≤ X5 < 1). <>

[0024] The active layer 15 emits and amplifies spontaneous emission light, and holes and electrons injected from the first electrode 21 and the second electrode 22 recombine by light emission to generate stimulated emission light. The active layer 15 has, for example, a multiple quantum well (MQW) structure in which a plurality of quantum well layers (not shown) and barrier layers (not shown) are alternately stacked. The quantum well layer is made of, for example, In X6 Ga 1-X6 As(0 < X6 < 1), and the barrier layer is made of, for example, In X7 Ga 1-X7 As(0 < X7 < X6).

[0025] The second spacer layer 16, together with the first spacer layer 14, adjusts the distance between the first DBR layer 13 and the second DBR layer 17 to be λ. The second spacer layer 16 is made of, for example, p-type Al X8 Ga 1-X8 As(0 ≤ X8 < 1).

[0026] The second DBR layer 17 is made of, for example, a p-type semiconductor material. The second DBR layer 17 faces the first DBR layer 13 with the active layer 15 in between, and constitutes a resonator for resonating the light with wavelength λ generated in the active layer 15 between the first DBR layer 13 to cause laser oscillation. Similar to the first DBR layer 13, the second DBR layer 17 has a structure in which low refractive index layers (not shown) and high refractive index layers (not shown) are alternately stacked. The low refractive index layer has an optical film thickness of λ × 1 / 4p of p-type Al X9 Ga1-X9 It consists of As(0 < X9 ≤ 1), and the high refractive index layer is, for example, p-type Al with an optical film thickness of λ × 1 / 4p X10 Ga 1-X10 It consists of As(0 ≤ X10 < X9).

[0027] The second contact layer 18 is for making an ohmic contact between the second DBR layer 17 of each light emitting element 10 and the second electrode 22. The second contact layer 18 is composed of a GaAs-based semiconductor. The second contact layer 18 is, for example, n-type Al X11 Ga 1-X11 It consists of As(0 ≤ X11 < 1).

[0028] The first electrode 21 is provided, for example, between a plurality of light emitting elements 10 on the surface 11S1 side of the substrate 11. In other words, the first electrode 21 is provided as a common electrode for a plurality of light emitting elements 10 arranged in an array in the light emitting region R1, on the bottom surface of the recess H provided around the plurality of light emitting elements 10. The first electrode 21 is formed, for example, by a multilayer film of titanium (Ti) / platinum (Pt) / gold (Au).

[0029] The second electrode 22 is provided above a plurality of light emitting elements 10, specifically, on each of the second contact layers 18. The second electrode 22 is formed, for example, by a multilayer film of gold-germanium (Au-Ge) / nickel (Ni) / gold (Au).

[0030] The insulating film 23 is formed, for example, continuously on the upper surface of the second contact layer 18, the side surfaces of the second contact layer 18 and the light emitting element 10, and the upper surface of the first contact layer 12. The insulating film 23 is composed of, for example, a single layer film or a laminated film such as silicon nitride (SiN) or silicon oxide (SiO2). Openings H3 and H4 (for example, refer to FIG. 4G) are provided at predetermined positions on the upper surface of the insulating film 23 on the second contact layer 18 and the first contact layer 12, respectively, and the first electrode 21 or the second electrode 22 is embedded in each of the openings H3 and H4.

[0031] The antireflection film 24 is formed, for example, on the entire rear surface 11S2 of the substrate 11. The antireflection film 24 is made of, for example, a single layer film or a multilayer film of silicon nitride (SiN), silicon oxide (SiO2), or the like.

[0032] [Operation of light-emitting element array] The light-emitting element array 1 is mounted, for example, on a laser driver with the upper surfaces 10S1 of the light-emitting elements 10 facing each other. The laser driver has, for example, a driver on a substrate that controls the voltage applied to the light-emitting element array 1. This driver is electrically connected to the light-emitting element array via, for example, wiring, and generates drive pulses that cause the multiple light-emitting elements 10 provided in the light-emitting element array 1 to emit and extinguish light.

[0033] In the light-emitting element array 1, a predetermined voltage is applied from the laser driver to the first electrode 21 and the second electrode 22, thereby applying a voltage to each of the multiple light-emitting elements 10 arranged in a two-dimensional array. As a result, holes are injected from the first electrode 21 and electrons are injected from the second electrode 22 into the active layer 15, and light is generated by recombination of the electrons and holes. The light generated in the active layer 15 resonates and is amplified between the first DBR layer 13 and the second DBR layer 17, and laser light L is emitted from the back surface 11S2 of the substrate 11.

[0034] [Method of manufacturing the light-emitting element array] Next, a method for manufacturing the light-emitting element array 1 will be described with reference to FIG. 3 and FIGS. 4A to 4H.

[0035] 4A, a compound semiconductor layer (semiconductor stack) is formed in this order on a substrate 11 made of, for example, GaAs by epitaxial crystal growth such as metal organic chemical vapor deposition (MOCVD) to form a compound semiconductor layer (semiconductor stack) (step S101). The compound semiconductor materials used are methyl-based organometallic compounds such as trimethylaluminum (TMAl), trimethylgallium (TMGa), and trimethylindium (TMIn), and arsine (AsH) gas. The donor impurity material is, for example, disilane (SiH), and the acceptor impurity material is, for example, carbon tetrabromide (CBr).

[0036] Next, as shown in FIG. 4B, a resist layer 31 having a pattern with varying densities is formed on the second contact layer 18. Next, as shown in FIG. 4C, the compound semiconductor layer is etched using this resist layer 31 as a mask to form a mesa structure (light-emitting element 10) (step S102). At this time, it is preferable to perform reactive ion etching (RIE) using, for example, a Cl-based gas under conditions that enhance the microloading effect. The microloading effect is a phenomenon in which ions are blocked by the mask in areas with a dense mask pattern, resulting in a lower etching rate than in areas with a sparse mask pattern.

[0037] By performing RIE under conditions that enhance this microloading effect, a difference in etching rate occurs between a region where a plurality of light-emitting elements 10 are arranged relatively densely (e.g., a first region R1-1) and a region where a plurality of light-emitting elements 10 are arranged relatively sparsely (e.g., a second region R1-2). For example, as described above, a recess H1 having a bottom surface within the first contact layer 12 is formed between adjacent light-emitting elements 10 arranged at a first pitch l1, and a recess H2 penetrating the first contact layer 12 is formed between adjacent light-emitting elements 10 arranged at a second pitch l2. Note that, in order to enhance the microloading effect, it is preferable to perform RIE under conditions of, for example, 80°C or less, and more preferably, room temperature (e.g., 25°C).

[0038] Next, after removing the resist layer 31, as shown in FIG. 4D, a high-temperature treatment is performed in a water vapor atmosphere, for example, to form the current confinement layer 19 (step S103). This oxidation may be performed by wet oxidation. As a result, the outer peripheral region of the current confinement layer 19 is oxidized, and a current confinement region 19B is formed.

[0039] Next, as shown in Fig. 4E, an insulating film 23 is formed continuously from the top surface of the second contact layer 18 to the side and bottom surfaces of the recesses H1 and H2 using, for example, a chemical vapor deposition (CVD) method or an atomic layer deposition (ALD) method (step S104). Subsequently, as shown in Fig. 4F, a resist layer 32 having a predetermined pattern is formed on the insulating film 23, and then openings H3 and H4 are formed at predetermined positions in the insulating film 23 using, for example, RIE (step S105) as shown in Fig. 4G.

[0040] Next, as shown in FIG. 4H, the first electrode 21 and the second electrode 22 are formed, for example, by lift-off using a resist pattern (step S106). Subsequently, the substrate 11 is thinned to a predetermined thickness by, for example, backside grinding and chemical polishing (CMP) (step S107). After that, an anti-reflection film 24 is formed on the backside 11S2 of the substrate 11 by, for example, CVD or ALD (step S108). Through the above steps, the light-emitting element array 1 shown in FIG. 1 is completed.

[0041] [Actions and Effects] In the light-emitting element array 1 of the present embodiment, recesses H (e.g., recesses H1, H2) having different depths according to the intervals between adjacent light-emitting elements 10 are formed around a plurality of rear-emitting light-emitting elements 10 arranged in a two-dimensional array at different intervals in the light-emitting region R1. This will be described below.

[0042] Generally, in a light-emitting element array 1000 having a common electrode 1021 on the back surface, as shown in Figure 5, the bottom surfaces of the mesas constituting the multiple light-emitting elements 1010 arranged in the array section R1000 are formed at a uniform height. This configuration is not a major problem in an array with a wide mesa pitch. However, in an array with a narrow mesa pitch, as shown by the arrows in Figure 5, current flows vertically toward the common electrode 1021 in the light-emitting element 1010A at the center of the array section R1000 due to the influence of neighboring light-emitting elements 1010. However, in the light-emitting element 1010B near the outer periphery R2000 of the array, the current spreads due to the reduced number of neighboring light-emitting elements, and the electrical resistance of the light-emitting element tends to decrease. This causes current to concentrate in the light-emitting element 1010B near the outer periphery R2000, resulting in a problem of non-uniform light emission within the array.

[0043] This problem also occurs in arrays where the arrangement pitch of multiple light-emitting elements varies. For example, in high-density areas where the arrangement pitch of multiple light-emitting elements is narrow, current flows vertically toward the common electrode on the back surface. However, in low-density areas where the arrangement pitch of multiple light-emitting elements is wide, the current spreads as in light-emitting element 1010B near the periphery R2000, reducing the electrical resistance of the light-emitting elements. This causes current to concentrate in the light-emitting elements in the low-density areas, preventing uniform light emission within the array.

[0044] This problem also occurs in light-emitting element arrays that do not have a common electrode on the back surface, such as back-emitting light-emitting element arrays. In back-emitting light-emitting element arrays, the common electrode is formed on the bottom surface of the mesa. In high-density regions where the arrangement pitch of multiple light-emitting elements is narrow, the area of ​​the common electrode formed on the bottom surface of the mesa is small, resulting in high electrical resistance of the light-emitting elements. In low-density regions where the arrangement pitch of multiple light-emitting elements is wide, the area of ​​the common electrode is large, resulting in low electrical resistance of the light-emitting elements. This causes current to concentrate in the light-emitting elements in the low-density region, preventing uniform light emission within the array.

[0045] In contrast to this, in the present embodiment, in the light-emitting element array 1 in which the plurality of light-emitting elements 10 are arranged at different intervals, recesses H (e.g., recesses H1, H2) of different depths are provided according to the intervals between adjacent light-emitting elements 10. As a result, in a high-density region in which the arrangement pitch of the plurality of light-emitting elements 10 is narrow (e.g., a first region R1-1 in which the plurality of light-emitting elements 10 are arranged at a first pitch l1), the area of ​​the first electrode 21 formed on the bottom surface of the recess H1 between adjacent light-emitting elements 10 becomes small, and therefore the electrical resistance of the light-emitting element 10 becomes high. However, since the recess H1 formed around the light-emitting element 10 is shallow, the electrical resistance of the current flowing horizontally through the first contact layer 12 from the first electrode 21 toward the light-emitting element 10 decreases. On the other hand, in a low-density region where the arrangement pitch of the plurality of light-emitting elements 10 is wide (for example, the second region R1-2 where the plurality of light-emitting elements 10 are arranged at the second pitch l2), the area of ​​the first electrode 21 formed on the bottom surface of the recess H1 between adjacent light-emitting elements 10 is large, so the electrical resistance of the light-emitting elements 10 is lower than that of the light-emitting elements 10 arranged in the first region R1-1. However, because the recess H2 formed around the light-emitting elements 10 is deep, the electrical resistance of the current flowing horizontally through the first contact layer 12 from the first electrode 21 toward the light-emitting element increases. This suppresses the concentration of current in the light-emitting elements 10 arranged at a low density. In other words, the difference in electrical resistance caused by the arrangement density of the plurality of light-emitting elements is offset.

[0046] As described above, in the light-emitting element array 1 of this embodiment, it is possible to obtain substantially uniform light emission in the light-emitting region R1.

[0047] Furthermore, in the light-emitting element array 1 of the present embodiment, in a low-density region (e.g., the second region R1-2) where the arrangement pitch of the plurality of light-emitting elements 10 is wide, the recesses H2 forming the mesa shape of the light-emitting elements 10 penetrate the first contact layer 12. This reduces the contact area between the first electrode 21 and the first contact layer 12, further suppressing current concentration in the light-emitting elements 10 arranged at a low density. This makes it possible to obtain more substantially uniform light emission in the light-emitting region R1.

[0048] Next, a second embodiment, a modified example, and application examples of the present disclosure will be described. In the following, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0049] <2. Second embodiment> Fig. 6 is a schematic diagram showing an example of a cross-sectional configuration of a light-emitting element array 2 according to a second embodiment of the present disclosure. Fig. 7 is a schematic diagram showing an example of a planar configuration of the entire light-emitting element array 2 shown in Fig. 6. Fig. 6 shows a cross section corresponding to line II-II' shown in Fig. 7. This light-emitting element array 2 is, for example, a two-dimensional array of surface-emitting VCSELs (Vertical Cavity Surface Emitting LASERs).

[0050] [Configuration of light-emitting element array] The light-emitting element array 2 has, for example, a substrate having a first surface (front surface 41S1) and a second surface (rear surface 41S2) facing each other, on a surface 41S1 of which a plurality of light-emitting elements 40 are arranged. Similar to the light-emitting element array 1 of the first embodiment, the light-emitting element array 2 has a light-emitting region R1 in which a plurality of light-emitting elements 40 are arranged in a two-dimensional array, and a peripheral region R2 provided on the outer periphery thereof.

[0051] Each of the plurality of light-emitting elements 40 has a mesa shape. The diameter (mesa diameter) of each light-emitting element 40 is slightly smaller than the minimum beam pitch of the laser light emitted from each light-emitting element 40. For example, if the minimum beam pitch is to be about 18 μm, the mesa diameter is set to about 14 μm.

[0052] In the light-emitting element array 2, a plurality of light-emitting elements 40 are arranged at different intervals from each other in the light-emitting region R1, similar to the light-emitting element array 1 of the first embodiment. For example, in the light-emitting region R1, as shown in FIG. 7, a first region R1-1 in which a plurality of light-emitting elements 40 are arranged at a first pitch l3 and a second region R1-2 in which a plurality of light-emitting elements 40 are arranged at a second pitch l4 are alternately arranged in the matrix direction. In addition, the plurality of light-emitting elements 40 may be randomly arranged within the light-emitting region R1 such that the intervals between adjacent light-emitting elements 40 are irregularly different.

[0053] Furthermore, the light-emitting element array 2 has recesses H each having a plurality of light-emitting elements 40 in a mesa shape. The recess H has different depths according to the intervals between adjacent plurality of light-emitting elements 40. For example, when the arrangement pitches (first pitch l3 and second pitch l4) of the plurality of light-emitting elements 40 arranged in the first region R1-1 and the second region R1-2 shown in FIG. 7 have a relationship of l3 < l4, the depth h3 of the recess H5 provided between adjacent light-emitting elements 40 in the first region R1-1 and the depth h4 of the recess H6 provided between adjacent light-emitting elements 40 in the second region R1-2 have a relationship of h3 < h4. That is, in the light-emitting element array 2 of the present embodiment, recesses H are formed around a plurality of light-emitting elements 40 arranged at different intervals from each other, such that the closer the intervals between adjacent light-emitting elements 40 are, the shallower the recesses H are, and the wider the intervals between adjacent light-emitting elements 40 are, the deeper the recesses H are.

[0054] The first pitch l3 and the second pitch l4 are each the distance between the centers of adjacent light-emitting elements 40 in the first region R1-1 and the second region R1-2.

[0055] [Configuration of Light-Emitting Element] The plurality of light-emitting elements 40 are VCSELs that emit laser light in the stacking direction. Each of the plurality of light-emitting elements 40 includes, for example, a first DBR layer 43 including a current constriction layer 49 therein, a first spacer layer 44, an active layer 45, a second spacer layer 46, and a second DBR layer 47 stacked in this order. A first contact layer 42 is provided between the plurality of light-emitting elements 40 and the substrate 41. A second contact layer 48 is provided on an upper surface 40S1 of each of the plurality of light-emitting elements 40.

[0056] In the present embodiment, a first electrode 51 is provided as a common electrode for the plurality of light-emitting elements 40 on, for example, the entire back surface 41S2 of the substrate 41. For example, the upper surface of the first contact layer 42 or the first DBR layer 43, the side surfaces of the plurality of light-emitting elements 40, and the upper surface of the second contact layer 48 are covered in this order with an insulating film 53 and a second electrode 52. The insulating film 53 has an opening on the upper surface of the second contact layer 48, and the second electrode 52 is electrically connected to the second contact layer 48 through the opening (opening H7, see FIG. 9B). These points are different from the light-emitting element 10 of the first embodiment, but the other configurations are similar to those of the light-emitting element 10.

[0057] [Operation of light-emitting element array] In the light-emitting element array 2, a predetermined voltage is applied from the laser driver to the first electrode 51 and the second electrode 52, whereby a voltage is applied from the first electrode 51 to the first electrode 51 and the second electrode 52 to each of the light-emitting elements 40. As a result, holes are injected from the first electrode 51 and electrons are injected from the second electrode 52 into the active layer 45, and light is generated by recombination of the electrons and holes. The light generated in the active layer 45 resonates and is amplified between the first DBR layer 43 and the second DBR layer 47, and laser light L is emitted from the top surface 40S1 of the light-emitting element 40.

[0058] [Method of manufacturing the light-emitting element array] Next, a method for manufacturing the light-emitting element array 2 will be described with reference to FIG. 8 and FIGS. 9A to 9C.

[0059] First, similarly to the first embodiment, steps S201 to S204 are performed to form an insulating film 53 that extends from the top surface of the second contact layer 48 to the side and bottom surfaces of the recesses H5 and H6, for example, by using a CVD method or an ALD method, as shown in Fig. 9A. Then, similarly to the first embodiment, as shown in Fig. 9B, an opening H7 is formed at a predetermined position in the insulating film 23 formed on the second contact layer 48 (step S205).

[0060] Next, as shown in FIG. 9C, the second electrode 52 is formed by, for example, a lift-off method using a resist pattern (step S206). Subsequently, the substrate 41 is thinned to a predetermined thickness by, for example, CMP (step S207). After that, the first electrode 51 is formed on the rear surface 11S2 of the substrate 41 by, for example, a CVD method or an ALD method (step S208). In this way, the light-emitting element array 2 shown in FIG. 6 is completed.

[0061] [Actions and Effects] The light-emitting element array 2 of this embodiment is configured so that recesses H (e.g., recesses H5, H6) of varying depths depending on the spacing between adjacent light-emitting elements 40 are formed around a plurality of surface-emitting light-emitting elements 40 arranged in a two-dimensional array at different intervals in the light-emitting region R1.

[0062] As a result, in a high-density region where the arrangement pitch of the plurality of light-emitting elements 40 is narrow (for example, the first region R1-1 where the plurality of light-emitting elements 40 are arranged at the first pitch 11), the area of ​​the first electrode 51 corresponding to each light-emitting element 40 becomes small, and the electrical resistance of the light-emitting element 40 becomes high. However, since the recess H5 formed around the light-emitting element 40 is shallow and is formed so as to have its bottom surface, for example, within the first DBR layer 43, the electrical resistance of the current flowing horizontally from the first electrode 51 to the light-emitting element 40 decreases. At that time, since the current path within the light-emitting element 40 is short, the electrical resistance of the current flowing through the light-emitting element 40 also decreases. On the other hand, in a low-density region where the arrangement pitch of the plurality of light-emitting elements 40 is wide (for example, the second region R1-2 where the plurality of light-emitting elements 40 are arranged at the second pitch l2), the area of ​​the first electrode 51 corresponding to each light-emitting element 40 is large, and therefore the electrical resistance of the light-emitting element 40 is lower than that of the light-emitting element 40 arranged in the first region R1-1. However, since the recesses H6 formed around the light-emitting element 40 are deep and have their bottoms in the first contact layer 42, for example, the electrical resistance of the current flowing horizontally from the first electrode 51 to the light-emitting element 40 increases. At that time, since the current path within the light-emitting element 40 is long, the electrical resistance of the current flowing through the light-emitting element 40 also increases. Therefore, for example, as shown by the arrows in FIG. 10, the difference in electrical resistance caused by the arrangement density of the plurality of light-emitting elements is offset.

[0063] As described above, in the light-emitting element array 2 of this embodiment, similar to the light-emitting element array 2 of the first embodiment, it is possible to obtain substantially uniform light emission in the light-emitting region R1.

[0064] <3. Modifications> Fig. 11 is a schematic diagram showing an example of a cross-sectional configuration of a light-emitting element array 3 as a modification of the first embodiment. Fig. 12 is a schematic diagram showing an example of a cross-sectional configuration of a light-emitting element array 4 as a modification of the second embodiment. The light-emitting element arrays 3 and 4 of these modifications differ from the first and second embodiments in that a current diffusion adjustment layer 25 is provided between the substrate 11 and the first contact layer 12, and between the substrate 41 and the first contact layer 42, respectively.

[0065] The current diffusion adjustment layer 25 is intended to adjust the amount of change in electrical resistance of the current flowing horizontally from the first electrode 21 or the first electrode 51 toward the light emitting element, which changes depending on the depth of the recess H. The current diffusion adjustment layer 25 has a lower carrier concentration than the first contact layers 12, 42. The current diffusion adjustment layer 25 may also be configured to modulate the carrier concentration in the stacking direction (e.g., the Z-axis direction). For example, the carrier concentration may be gradually increased from the substrate 11 side toward the first contact layer 12.

[0066] As described above, in the light-emitting element arrays 3 and 4 of this modification, the current diffusion adjustment layer 25 is provided between the substrate 11 and the first contact layer 12 and between the substrate 41 and the first contact layer 42, respectively. This makes it possible to control the adjustment range of the current resistance and further offset the difference in electrical resistance caused by the arrangement density of the multiple light-emitting elements 10 and 40. This makes it possible to obtain more uniform light emission in the light-emitting region R1.

[0067] Furthermore, by modulating the concentration of carriers contained in the current diffusion adjustment layer 25, for example, as described above, it becomes possible to freely control the adjustment range of the current resistance.

[0068] 12 shows an example in which the current diffusion adjustment layer 25 is provided between the substrate 41 and the first contact layer 42, but the present invention is not limited to this. For example, the current diffusion adjustment layer 25 may be provided between the first contact layer 42 and the first DBR layer 43. In this case, the same effect can be obtained.

[0069] <4. Application Examples> This technology can be applied to various electronic devices that include semiconductor lasers, such as light sources provided in mobile electronic devices such as smartphones, and light sources in various sensing devices that detect shape, movement, etc.

[0070] 13 is a block diagram showing a schematic configuration of a distance measuring device (distance measuring device 100) using an illumination device 110 equipped with the above-described light-emitting element array (e.g., light-emitting element array 1). The distance measuring device 100 measures distance using the ToF method. The distance measuring device 100 includes, for example, the illumination device 110, a light-receiving unit 120, a control unit 130, and a distance measuring unit 140.

[0071] The lighting device 110 includes, for example, the light-emitting element array 1 shown in FIG. 1 as a light source. The lighting device 110 generates illumination light in synchronization with, for example, a square-wave light-emission control signal CLKp. The light-emission control signal CLKp is not limited to a square wave as long as it is a periodic signal. For example, the light-emission control signal CLKp may be a sine wave.

[0072] The light receiving unit 120 receives light reflected from the illumination target 200 and detects the amount of light received within each period of the vertical synchronization signal VSYNC. For example, a periodic signal of 60 hertz (Hz) is used as the vertical synchronization signal VSYNC. The light receiving unit 120 has a plurality of pixel circuits arranged in a two-dimensional lattice pattern. The light receiving unit 120 supplies image data (frames) corresponding to the amount of light received by these pixel circuits to the distance measuring unit 140. The frequency of the vertical synchronization signal VSYNC is not limited to 60 hertz (Hz) and may be 30 hertz (Hz) or 120 hertz (Hz).

[0073] The control unit 130 controls the lighting device 110. The control unit 130 generates a light emission control signal CLKp and supplies it to the lighting device 110 and the light receiving unit 120. The frequency of the light emission control signal CLKp is, for example, 20 megahertz (MHz). Note that the frequency of the light emission control signal CLKp is not limited to 20 megahertz (MHz) and may be, for example, 5 megahertz (MHz).

[0074] The distance measurement unit 140 measures the distance to the irradiation object 200 using the ToF method based on image data. This distance measurement unit 140 measures the distance for each pixel circuit and generates a depth map that indicates the distance to the object for each pixel using a grayscale value. This depth map is used, for example, in image processing that performs blurring processing according to the distance, autofocus (AF) processing that determines the focal point of a focus lens according to the distance, etc.

[0075] <5. Application Examples> (Example of application to a moving object) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0076] FIG. 14 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0077] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 14, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0078] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating a braking force of the vehicle, etc.

[0079] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches may be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0080] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc., based on the received images.

[0081] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0082] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0083] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drivetrain control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including avoiding or mitigating collisions between vehicles, following based on the distance between vehicles, maintaining vehicle speed, warning of vehicle collisions, or warning of vehicle lane departure.

[0084] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0085] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information about the outside of the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0086] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 57, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as output devices. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0087] FIG. 15 is a diagram showing an example of the installation position of the imaging unit 12031.

[0088] In FIG. 15, a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.

[0089] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The forward images acquired by the imaging units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0090] 15 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 viewed from above can be obtained.

[0091] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of multiple imaging elements, or may be an imaging element having pixels for phase difference detection.

[0092] For example, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104, thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (for example, 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of automatic driving, which runs autonomously without relying on driver operation.

[0093] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drivetrain control unit 12010.

[0094] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the images captured by the image capturing units 12101 to 12104. The pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104, which are infrared cameras, and then performing pattern matching on a series of feature points that indicate the outline of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0095] An example of a mobile object control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 of the above-described configuration. Specifically, the light-emitting element array 1 can be applied to the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to perform highly accurate control using captured images in the mobile object control system.

[0096] The present technology has been described above using the first and second embodiments, modifications, and application examples. However, the present technology is not limited to the above-described embodiments and can be modified in various ways. For example, the layer structure of the light-emitting element 10 described in the above-described embodiments is an example, and other layers may be included. Furthermore, the materials of each layer are also an example, and are not limited to those described above.

[0097] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0098] The present technology can be configured as follows. According to the present technology configured as follows, after a plurality of compound semiconductor layers constituting a light-emitting element are sequentially stacked on a substrate, a resist layer having a pattern with different densities is formed on the compound semiconductor layer, and reactive ion etching is performed at 80°C or less using the resist layer as a mask. As a result, a plurality of light-emitting elements having a mesa shape are formed in a two-dimensional array on the first surface at different intervals, and recesses having depths that vary depending on the intervals between adjacent light-emitting elements are formed between adjacent light-emitting elements. Therefore, differences in electrical resistance caused by the arrangement density of the light-emitting elements are canceled out, and approximately uniform light emission can be obtained within the surface. (1) a substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light emitting elements, forming the mesa shape, and having a depth that varies depending on the interval between the plurality of adjacent light emitting elements; Equipped with the substrate further has an array section in which the plurality of light-emitting elements are arranged in a two-dimensional array, The array section has a plurality of regions, and the plurality of light-emitting elements are arranged at different intervals in each of the regions. Light-emitting element array. (2) The light-emitting element array according to (1), wherein the depth of the recess is shallower as the interval between adjacent light-emitting elements is narrower, and is deeper as the interval between adjacent light-emitting elements is wider. (3 ) before the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate; a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on a surface of the second light reflecting layer opposite to the active layer; (1) or (2) above The light-emitting element array according to claim 1. (4) The light-emitting element further includes a first electrode provided on a bottom of the recess and a second electrode provided on the second contact layer. (3) The light-emitting element array according to claim 1. (5) the light-emitting element is a back-emitting surface-emitting laser that emits laser light from the second surface, (3) or (4) above The light-emitting element array according to claim 1. (6) the recesses include first recesses provided between the plurality of light-emitting elements arranged at a first interval between adjacent light-emitting elements, and second recesses provided between the plurality of light-emitting elements arranged at a second interval wider than the first interval between adjacent light-emitting elements, the first recess has a bottom surface within the first contact layer, and the second recess penetrates the first contact layer. Any one of (3) to (5) above The light-emitting element array according to claim 1. (7) a current diffusion adjusting layer between the substrate and the first contact layer, the current diffusion adjusting layer having a carrier concentration lower than that of the first contact layer; (6) The light-emitting element array according to claim 1. (8) the current diffusion adjustment layer has a carrier concentration that changes from the substrate toward the first contact layer; (7) The light-emitting element array according to claim 1. (9) The light-emitting element further includes a first electrode provided on the second surface side of the substrate and a second electrode provided on the second contact layer. Any one of the above (3) to (8) The light-emitting element array according to claim 1. (10) the first electrode is a common electrode for the plurality of light-emitting elements; (9) The light-emitting element array according to claim 1. (11) The laser is a surface-emitting type surface-emitting laser that emits laser light from the second contact layer side. Any one of the above (4) to (10) The light-emitting element array according to claim 1. (12) the recesses include a first recess provided between the adjacent light-emitting elements arranged at a first interval, and a second recess provided between the adjacent light-emitting elements arranged at a second interval wider than the first interval, the first recess has a bottom surface within the first light-reflecting layer, and the second recess penetrates the first light-reflecting layer; Any one of (4) to (11) above The light-emitting element array according to claim 1. (13) a current diffusion adjusting layer between the substrate and the first contact layer or between the first contact layer and the first light reflecting layer; (11) or (12) above The light-emitting element array according to claim 1. (14) the current diffusion adjustment layer has a carrier concentration that changes from the substrate toward the first light reflective layer; (13) The light-emitting element array according to claim 1. (15) a substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the substrate further has an array section in which the plurality of light-emitting elements are arranged in a two-dimensional array, The plurality of light emitting elements are randomly arranged in the array section. Light-emitting element array. (16) a substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on the surface of the second light reflecting layer opposite to the active layer; the recesses include first recesses provided between the plurality of light-emitting elements arranged at a first interval between adjacent light-emitting elements, and second recesses provided between the plurality of light-emitting elements arranged at a second interval wider than the first interval between adjacent light-emitting elements, The first recess has a bottom surface within the first contact layer, and the second recess penetrates the first contact layer. Light-emitting element array. (17) a substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on a surface of the second light reflecting layer opposite to the active layer; the recesses include a first recess provided between the adjacent light-emitting elements arranged at a first interval, and a second recess provided between the adjacent light-emitting elements arranged at a second interval wider than the first interval, The first recess has a bottom surface within the first light-reflecting layer, and the second recess penetrates the first light-reflecting layer. Light-emitting element array. (18) a substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on a surface of the second light reflecting layer opposite to the active layer; a surface-emitting surface-emitting laser that emits laser light from the second contact layer side, A current diffusion adjusting layer is further provided between the substrate and the first contact layer or between the first contact layer and the first light reflecting layer. Light-emitting element array.

[0099] This application claims priority based on Japanese Patent Application No. 2021-140414, filed on August 30, 2021, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0100] 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 substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the substrate further includes an array portion in which the plurality of light-emitting elements are arranged in a two-dimensional array; The array section has a plurality of regions, and the plurality of light-emitting elements are arranged at different intervals in each of the regions. Light-emitting element array.

2. The light-emitting element array according to claim 1 , wherein the depth of the recess is shallower as the interval between adjacent light-emitting elements is narrower, and is deeper as the interval between adjacent light-emitting elements is wider.

3. the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, 2. The light-emitting element array according to claim 1, further comprising a first contact layer provided between the first light-reflecting layer and the substrate, and a second contact layer on the surface of the second light-reflecting layer opposite the active layer.

4. 4. The light-emitting element array according to claim 3, wherein the light-emitting element further comprises a first electrode provided on a bottom of the recess, and a second electrode provided on the second contact layer.

5. 4. The light-emitting element array according to claim 3, wherein the light-emitting element is a back-emitting surface-emitting laser that emits laser light from the second surface.

6. the recesses include first recesses provided between the plurality of light-emitting elements arranged at a first interval between adjacent light-emitting elements, and second recesses provided between the plurality of light-emitting elements arranged at a second interval wider than the first interval between adjacent light-emitting elements, 4. The light-emitting element array according to claim 3, wherein the first recess has a bottom surface within the first contact layer, and the second recess penetrates the first contact layer.

7. 7. The light-emitting element array according to claim 6, further comprising a current diffusion adjustment layer between the substrate and the first contact layer, the current diffusion adjustment layer having a carrier concentration lower than that of the first contact layer.

8. 8. The light-emitting element array according to claim 7, wherein the current diffusion adjustment layer has a carrier concentration that changes from the substrate toward the first contact layer.

9. The light-emitting element array according to claim 3 , wherein the light-emitting element further comprises a first electrode provided on the second surface side of the substrate, and a second electrode provided on the second contact layer.

10. The light-emitting element array according to claim 9 , wherein the first electrode is a common electrode for the plurality of light-emitting elements.

11. 4. The light-emitting element array according to claim 3, wherein the light-emitting element array is a surface-emitting laser of a surface-emitting type that emits laser light from the second contact layer side.

12. the recesses include a first recess provided between the plurality of adjacent light-emitting elements arranged at a first interval, and a second recess provided between the plurality of adjacent light-emitting elements arranged at a second interval wider than the first interval, The light-emitting element array according to claim 3 , wherein the first recess has a bottom surface within the first light-reflecting layer, and the second recess penetrates the first light-reflecting layer.

13. The light-emitting element array according to claim 11, further comprising a current diffusion adjustment layer between the substrate and the first contact layer or between the first contact layer and the first light-reflecting layer.

14. The light-emitting element array according to claim 13 , wherein the current diffusion adjustment layer has a carrier concentration that changes from the substrate toward the first light reflecting layer.

15. A substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the substrate further includes an array portion in which the plurality of light-emitting elements are arranged in a two-dimensional array; The plurality of light emitting elements are randomly arranged in the array section. Light-emitting element array.

16. A substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on the surface of the second light reflecting layer opposite to the active layer; the recesses include first recesses provided between the plurality of light-emitting elements arranged at a first interval between adjacent light-emitting elements, and second recesses provided between the plurality of light-emitting elements arranged at a second interval wider than the first interval between adjacent light-emitting elements, The first recess has a bottom surface within the first contact layer, and the second recess penetrates the first contact layer. Light-emitting element array.

17. A substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on a surface of the second light reflecting layer opposite to the active layer; the recesses include a first recess provided between the plurality of adjacent light-emitting elements arranged at a first interval, and a second recess provided between the plurality of adjacent light-emitting elements arranged at a second interval wider than the first interval, The first recess has a bottom surface within the first light-reflecting layer, and the second recess penetrates the first light-reflecting layer. Light-emitting element array.

18. A substrate having opposing first and second surfaces; a plurality of light emitting elements, each having a mesa shape, arranged in a two-dimensional array on the first surface at different intervals; a recess provided around the plurality of light-emitting elements, forming the mesa shape, and having a depth that varies according to the interval between adjacent light-emitting elements; the light-emitting element has a first light-reflecting layer, an active layer, and a second light-reflecting layer stacked in this order from the first surface side of the substrate, a first contact layer provided between the first light reflecting layer and the substrate, and a second contact layer provided on a surface of the second light reflecting layer opposite to the active layer; a surface-emitting surface-emitting laser that emits laser light from the second contact layer side, a current diffusion adjusting layer between the substrate and the first contact layer or between the first contact layer and the first light reflecting layer; Light-emitting element array.

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