Patent Publication Number: US-2023163560-A1

Title: Light-emitting element array

Description:
TECHNICAL FIELD 
     The present technology relates to a light-emitting element array in which a plurality of light-emitting elements is arrayed. 
     BACKGROUND ART 
     A light-emitting element such as a vertical cavity surface emitting laser (VCSEL) element is often used as a light-emitting element array in which a plurality of light-emitting elements is arrayed. Here, in the light-emitting element array, wiring of each light-emitting element causes a problem in accordance with the number and density of light-emitting elements constituting the array. 
     For example, Patent Literature 1 discloses an image forming apparatus in which an anode wire and a cathode wire are connected to each of a large number of light-emitting elements arrayed in a matrix. The anode wire and the cathode wire are provided so as to extend in directions orthogonal to each other and intersect with each other and configured such that the size of the light-emitting unit can be reduced and the size of the individual light-emitting element can be increased. 
     Further, Patent Literature 2 discloses an image forming apparatus in which a first wire and a second wire are connected to each of a large number of light-emitting element arranged in an n×m matrix. N or more first wires are provided and n or more second wires intersecting with the first wires are provided, so that the wiring resistance and the electrostatic capacity of each wire can be suppressed. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent Application Laid-open No. 2001-063139 
     Patent Literature 2: Japanese Patent Application Laid-open No. 1998-107386 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     However, in the configuration described in Patent Literature 1, the space for providing wires is limited as the interval between light-emitting elements is reduced and it is difficult to form wires. Further, the configuration described in Patent Literature 2 has a problem that the operation delay increases as the density of the light-emitting elements increases. As described above, the existing technology has not sufficiently dealt with the increase in density of light-emitting elements from the viewpoint of the wiring structure. 
     In view of the circumstances as described above, it is an object of the present technology to provide a light-emitting element array having a wiring structure making it possible to increase the density of light-emitting elements. 
     Solution to Problem 
     In order to achieve the above-mentioned object, a light-emitting element array according to an embodiment of the present technology includes: a light-emitting element group; a first wire; and a second wire. 
     The light-emitting element group includes a plurality of first light-emitting elements and a plurality of second light-emitting elements that are arrayed in a planar manner to form a light-emitting element surface. 
     The first wire extends in a direction parallel to the light-emitting element surface, has a region overlapping with the plurality of first light-emitting elements and a region overlapping with the plurality of second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, is electrically connected to the plurality of first light-emitting elements, and is not electrically connected to the plurality of second light-emitting elements. 
     The second wire extends in a direction parallel to the light-emitting element surface, has a region overlapping with the plurality of first light-emitting elements and a region overlapping with the plurality of second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, is electrically connected to the plurality of second light-emitting elements, and is not electrically connected to the plurality of first light-emitting elements. 
     In accordance with this configuration, since each of the first wire and the second wire has the regions overlapping with the first light-emitting element and the second light-emitting element, the first wire is electrically connected to only the first light-emitting element, and the second wire is electrically connected to only the second light-emitting element, it is possible to make the first wire and the second wire independently emit light while increasing the density of the first wires and the second wires. 
     The light-emitting element group may include a first light-emitting element column in which the plurality of first light-emitting elements is arrayed, and a second light-emitting element column in which the plurality of second light-emitting elements is arrayed, 
     a center of the first wire may be separated from a center of the first light-emitting element column in a direction parallel to the light-emitting element surface, and 
     a center of the second wire may be separated from a center of the second light-emitting element column in a direction parallel to the light-emitting element surface. 
     The light-emitting element group may further include a third light-emitting element column in which the plurality of first light-emitting elements is arrayed, the third light-emitting element column being provided on a side opposite to the first light-emitting element column with respect to the second light-emitting element column, 
     the first wire may be provided between the center of the first light-emitting element column and the center of the second light-emitting element column as viewed from a direction perpendicular to the light-emitting element surface, and 
     the second wire may be provided between the center of the second light-emitting element column and a center of the third light-emitting element column as viewed from a direction perpendicular to the light-emitting element surface. 
     The first light-emitting element column, the second light-emitting element column, the third light-emitting element column, the first wire, and the second wire may each extend in a first direction parallel to the light-emitting element surface and are separated from each other in a second direction that is parallel to the light-emitting element surface and orthogonal to the first direction, 
     a width of the first wire in the second direction may be larger than an interval between the first light-emitting element column and the second light-emitting element column in the second direction, and 
     a width of the second wire in the second direction may be larger than an interval between the second light-emitting element column and the third light-emitting element column in the second direction. 
     The first wire and the second wire may be formed in a same layer. 
     The first wire may be stacked on the plurality of first light-emitting elements and the plurality of second light-emitting elements via an insulation layer, be electrically connected to the plurality of first light-emitting elements via a first through hole provided in the insulation layer on the plurality of first light-emitting elements, and be insulated from the plurality of second light-emitting elements by the insulation layer on the plurality of second light-emitting elements, and 
     the second wire may be stacked on the plurality of first light-emitting elements and the plurality of second light-emitting elements via the insulation layer, be electrically connected to the plurality of second light-emitting elements via a second through hole provided in the insulation layer on the plurality of second light-emitting elements, and be insulated from the plurality of first light-emitting elements by the insulation layer on the plurality of first light-emitting elements. 
     The plurality of first light-emitting elements may each be a vertical cavity surface emitting laser element and include a first light-emitting surface and a first electrode provided around the first light-emitting surface, 
     the plurality of second light-emitting elements may each be a vertical cavity surface emitting laser element and include a second light-emitting surface and a second electrode provided around the second light-emitting surface, 
     the first wire may abut on the first electrode via the first through hole in the plurality of first light-emitting elements, and 
     the second wire may abut on the second electrode via the second through hole in the plurality of second light-emitting elements. 
     The plurality of first light-emitting elements and the plurality of second light-emitting elements may each have a mesa structure surrounded by a recessed portion, 
     the light-emitting element group may include a first groove portion that connects the recessed portions to each other between the plurality of first light-emitting elements and a second groove portion that connects the recessed portions to each other between the plurality of second light-emitting elements, 
     the first wire may have a portion formed in the first groove portion, and 
     the second wire may have a portion formed in the second groove portion. 
     The light-emitting elements constituting the light-emitting element group may include a plurality of third light-emitting elements and a plurality of fourth light-emitting elements, the plurality of third light-emitting elements and the plurality of fourth light-emitting elements each having a mesa structure surrounded by a recessed portion, the recessed portion being separated from the light-emitting element surface and having a bottom surface parallel to the light-emitting element surface, an element isolation groove that electrically separates the plurality of third light-emitting elements and the plurality of fourth light-emitting elements from each other being provided in the bottom surface, and 
     the light-emitting element array may further include:
         a third wire that extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the third light-emitting element and a region of the bottom surface between the element isolation groove and the fourth light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the third light-emitting element, and is not electrically connected to the fourth light-emitting element; and   a fourth wire that extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the third light-emitting element and a region of the bottom surface between the element isolation groove and the fourth light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the fourth light-emitting element, and is not electrically connected to the third light-emitting element.       

     The light-emitting element group may include a first light-emitting element column in which the plurality of first light-emitting elements is arrayed, a second light-emitting element column in which the plurality of second light-emitting elements is arrayed, a third light-emitting element column in which the plurality of third light-emitting elements is arrayed, and a fourth light-emitting element column in which the plurality of fourth light-emitting elements is arrayed. 
     The first light-emitting element column, the second light-emitting element column, the first wire, and the second wire may each extend in a first direction parallel to the light-emitting element surface, and 
     the third light-emitting element column, the fourth light-emitting element column, the third wire, and the fourth wire may each extend in a second direction that is parallel to the light-emitting element surface and is orthogonal to the first direction. 
     The first light-emitting element column, the second light-emitting element column, the first wire, and the second wire may each extend in a first direction parallel to the light-emitting element surface, and 
     the third light-emitting element column, the fourth light-emitting element column, the third wire, and the fourth wire may each extend in the first direction. 
     The third wire may be stacked on the bottom surface and the element isolation groove via an insulation layer, be electrically connected to the plurality of third light-emitting elements via a first opening provided in the insulation layer in a region of the bottom surface between the element isolation groove and the third light-emitting element, and be insulated from the plurality of fourth light-emitting elements by the insulation layer in a region of the bottom surface between the element isolation groove and the fourth light-emitting element, and 
     the fourth wire may be stacked on the bottom surface and the element isolation groove via the insulation layer, be electrically connected to the plurality of fourth light-emitting elements via a second opening provided in the insulation layer in a region of the bottom surface between the element isolation groove and the fourth light-emitting element, and be insulated from the plurality of third light-emitting elements by the insulation layer in a region of the bottom surface between the element isolation groove and the third light-emitting element. 
     The third wire may have a width from the element isolation groove to a side of the third light-emitting element larger than a width from the element isolation groove to a side of the fourth light-emitting element, and 
     the fourth wire may have a width from the element isolation groove to a side of the fourth light-emitting element larger than a width from the element isolation groove to a side of the third light-emitting element. 
     In order to achieve the above-mentioned object, a light-emitting element array according to an embodiment of the present technology includes: a light-emitting element group; a first wire; and a second wire. 
     The light-emitting element group is a light-emitting element group in which a plurality of first light-emitting elements and a plurality of second light-emitting elements are arrayed in a planar manner to form a light-emitting element surface, the plurality of first light-emitting elements and the plurality of second light-emitting elements each having a mesa structure surrounded by a recessed portion, the recessed portion being separated from the light-emitting element surface and having a bottom surface parallel to the light-emitting element surface, an element isolation groove that electrically separates the plurality of first light-emitting elements and the plurality of second light-emitting elements from each other being provided in the bottom surface. 
     The first wire extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the first light-emitting element and a region of the bottom surface between the element isolation groove and the second light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the first light-emitting element, and is not electrically connected to the second light-emitting element. 
     The second wire extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the first light-emitting element and a region of the bottom surface between the element isolation groove and the second light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the second light-emitting element, and is not electrically connected to the first light-emitting element. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a plan view of a light-emitting element array according to an embodiment of the present technology. 
         FIG.  2    is an enlarged plan view of the light-emitting element array. 
         FIG.  3    is a cross-sectional view of the light-emitting element array. 
         FIG.  4    is a cross-sectional view of the light-emitting element array. 
         FIG.  5    is a plan view of a partial configuration of the light-emitting element array. 
         FIG.  6    is a cross-sectional view of a partial configuration of the light-emitting element array. 
         FIG.  7    is a plan view of a light-emitting element constituting the light-emitting element array. 
         FIG.  8    is a cross-sectional view of the light-emitting element constituting the light-emitting element array. 
         FIG.  9    is a cross-sectional view showing an insulation layer included in the light-emitting element array. 
         FIG.  10    is a plan view showing the insulation layer included in the light-emitting element array. 
         FIG.  11    is a cross-sectional view showing the insulation layer included in the light-emitting element array. 
         FIG.  12    is a plan view showing the insulation layer included in the light-emitting element array. 
         FIG.  13    is a cross-sectional view showing a connection relationship between a first light-emitting element, a first wire, and a second wire in the light-emitting element array. 
         FIG.  14    is a cross-sectional view showing a connection relationship between a second light-emitting element, the first wire, and the second wire in the light-emitting element array. 
         FIG.  15    is a plan view showing a light-emitting element column in the light-emitting element array. 
         FIG.  16    is a plan view showing a positional relationship between the light-emitting element column, the first wire, and the second wire in the light-emitting element array. 
         FIG.  17    is a plan view showing a positional relationship between first to third light-emitting element columns, the first wire, and the second wire in the light-emitting element array. 
         FIG.  18    is a plan view showing widths of the first wire and the second wire in the light-emitting element array. 
         FIG.  19    is a plan view of a light-emitting element array according to a Comparative Example. 
         FIG.  20    is a cross-sectional view of the light-emitting element array according to the Comparative Example. 
         FIG.  21    is a plan view of a light-emitting element array in which a groove portion is provided according to an embodiment of the present technology. 
         FIG.  22    is an enlarged plan view of the light-emitting element array. 
         FIG.  23    is a cross-sectional view of the light-emitting element array. 
         FIG.  24    is a plan view of a partial configuration of the light-emitting element array. 
         FIG.  25    is a plan view of a light-emitting element constituting a light-emitting element array according to a modified example of the present technology. 
         FIG.  26    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  27    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  28    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  29    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  30    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  31    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  32    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  33    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  34    is a plan view of the light-emitting element constituting the light-emitting element array according to the modified example of the present technology. 
         FIG.  35    is a cross-sectional view of the light-emitting element array according to the modified example of the present technology. 
         FIG.  36    is a plan view of the light-emitting element array according to the modified example of the present technology. 
         FIG.  37    is a plan view of the light-emitting element array according to the modified example of the present technology. 
         FIG.  38    is a plan view of a light-emitting element array that includes a third light-emitting element and a fourth light-emitting element according to an embodiment of the present technology. 
         FIG.  39    is a schematic diagram showing a light-emitting element column of the light-emitting element array. 
         FIG.  40    is a plan view of the light-emitting element array showing a third wire and a fourth wire. 
         FIG.  41    is an enlarged plan view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  42    is a cross-sectional view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  43    is a plan view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  44    is an enlarged plan view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  45    is a cross-sectional view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  46    is a plan view of the light-emitting element array showing a bottom surface of a recessed portion. 
         FIG.  47    is a cross-sectional view of the light-emitting element array showing the bottom surface of the recessed portion. 
         FIG.  48    is a plan view of the light-emitting element array showing an opening of an insulation layer. 
         FIG.  49    is a cross-sectional view of the light-emitting element array showing the opening of the insulation layer. 
         FIG.  40    is a plan view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  51    is an enlarged plan view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  52    is an enlarged plan view of the light-emitting element array showing the third wire and the fourth wire. 
         FIG.  53    is a schematic diagram showing a light-emitting element column of the light-emitting element array. 
     
    
    
     MODE(S) FOR CARRYING OUT THE INVENTION 
     A light-emitting element array according to an embodiment of the present technology will be described. 
     [Structure of Light-Emitting Element Array] 
       FIG.  1    is a plan view of a light-emitting element array  100  according to this embodiment, and  FIG.  2    is an enlarged view of  FIG.  1   .  FIG.  3    and  FIG.  4    are each a cross-sectional view of the light-emitting element array  100 .  FIG.  3    is a cross-sectional view taken along the line A-A in  FIG.  2   , and  FIG.  4    is a cross-sectional view taken along the line B-B in  FIG.  2   . As shown in these figures, the light-emitting element array  100  includes a first light-emitting element  121 , a second light-emitting element  122 , a first wire  131 , and a second wire  132 . 
       FIG.  5    is a plan view of the light-emitting element array  100  in which illustration of the first wire  131  and the second wire  132  is omitted.  FIG.  6    is a cross-sectional view of this light-emitting element array  100  and is a cross-sectional view taken along the line C-C in  FIG.  5   . 
     As shown in  FIG.  5   , the light-emitting element array  100  includes a light-emitting element group configured by arraying a plurality of first light-emitting elements  121  and a plurality of second light-emitting elements  122  in a planar manner. Hereinafter, as shown in  FIG.  6   , a surface on which the first light-emitting element  121  and the second light-emitting element  122  are arrayed will be referred to as the light-emitting element surface  120 , one surface parallel to the light-emitting element surface  120  will be referred to as the X direction, and a direction that is parallel to the light-emitting element surface  120  and is orthogonal to the X direction will be referred to as the Y direction. That is, the light-emitting element surface  120  is parallel to the X-Y plane. Further, a direction perpendicular to the light-emitting element surface  120  will be referred to as the Z direction. Note that the number of the first light-emitting elements  121  and the number of the second light-emitting elements  122  are not particularly limited and can each be, for example, several tens to several thousands. 
     The first light-emitting element  121  and the second light-emitting element  122  can be light-emitting elements having the same configuration.  FIG.  7    is a plan view of a light-emitting element  150  capable of constituting the first light-emitting element  121  and the second light-emitting element  122 , and  FIG.  8    is a cross-sectional view of the light-emitting element  150 . 
     The light-emitting element  150  is a vertical cavity surface emitting laser (VCSEL) element. As shown in  FIG.  7    and  FIG.  8   , the light-emitting element  150  has a mesa structure in which a mesa (plateau shape)  153  is formed by being surrounded by an annular recessed portion  152  provided on a substrate  151 . 
     As shown in  FIG.  8   , the light-emitting element  150  includes an n-type DBR layer  154 , an active layer  155 , a current confinement layer  156 , a p-type DBR layer  157 , a p-electrode  158 , and an n-electrode  159 . The n-type DBR layer  154 , the active layer  155 , the current confinement layer  156 , and the p-type DBR layer  157  are stacked on the substrate  151  in this order. 
     The n-type DBR layer  154  is formed of an n-type semiconductor material, functions as a DBR (Distributed Bragg Reflector), and reflects light having a specific wavelength (hereinafter, the wavelength λ). The n-type DBR layer  154  constitutes an optical resonator for laser oscillation together with the p-type DBR layer  157 . The active layer  155  is provided between the n-type DBR layer  154  and the p-type DBR layer  157 , and emits and amplifies spontaneously emitted light. The active layer  155  can include a plurality of layers obtained by alternately stacking a quantum well layer and a barrier layer. 
     The current confinement layer  156  is provided in the vicinity of the active layer  155  and imparts a confinement action to a current. The current confinement layer  156  includes a non-oxidized region  156   a  and an oxidized region  156   b.  The non-oxidized region  156   a  is provided in the center of the current confinement layer  156  and the oxidized region  156   b  is provided around the non-oxidized region  156   a.  The oxidized region  156   b  can be formed by performing oxidation treatment from the outer periphery side of a mesa  153  via the recessed portion  152 . 
     The p-type DBR layer  157  is formed of a p-type semiconductor material, functions as a DBR, and reflects light having the wavelength A. The p-type DBR layer  157  constitutes an optical resonator for laser oscillation together with the n-type DBR layer  154 . The p-electrode  158  is provided on the surface of the mesa  153  and is electrically connected to the p-type DBR layer  157 . As shown in  FIG.  7   , the p-electrode  158  has an annular shape. The n-electrode  159  is provided on the surface of the substrate  151  on the side opposite to the light-emitting element  150  and is electrically connected to the n-type DBR layer  154  via the substrate  151 . 
     The light-emitting element  150  has the configuration as described above. In the light-emitting element  150 , when a voltage is applied between the p-electrode  158  and the n-electrode  159 , a current flows between the p-electrode  158  and the n-electrode  159 . The current is subjected to a current confinement action by the current confinement layer  156  and is injected into the active layer  155  in the vicinity of the non-oxidized region  156   a.    
     This injected current causes spontaneously emitted light in the active layer  155 , and the spontaneously emitted light is reflected by the n-type DBR layer  154  and the p-type DBR layer  157 . Of the spontaneously emitted light, a component of the oscillation wavelength A forms a standing wave between the n-type DBR layer  154  and the p-type DBR layer  157  and is amplified by the active layer  155 . When the injected current exceeds a threshold value, laser oscillation of light forming a standing wave occurs, and a laser beam passes through the p-type DBR layer  157  and is emitted. In  FIG.  7    and  FIG.  8   , a surface from which a laser beam is emitted is shown as a light-emitting surface S. The p-electrode  158  is provided around the light-emitting surface S. 
     Note that the configuration of the light-emitting element  150  is not limited to the one shown here. For example, the n-type and the p-type in the light-emitting element  150  may be reversed. Further, although the configuration described above shows the configuration of a surface emission type VCSEL element, the light-emitting element  150  may be a backside emission type VCSEL. Further, the light-emitting element  150  is not limited to the VCSEL and may be a light-emitting element formed of a semiconductor such as an LED (Light Emitting Diode). 
     As shown in  FIG.  5   , the light-emitting element array  100  can be a light-emitting element array in which the first light-emitting element  121  and the second light-emitting element  122 , each of which has the configuration of the light-emitting element  150 , are arrayed. As shown in  FIG.  5   , in the first light-emitting element  121  and the second light-emitting element  122 , the size of the mesa  153  may differ or may be the same. 
     The first light-emitting element  121  and the second light-emitting element  122  have the configurations as described above. Here, the first light-emitting element  121  and the second light-emitting element  122  are configured to be capable of emitting light independently of each other. Specifically, as shown in  FIG.  8   , the n-electrode  159  is uniformly formed on the back surface of the substrate  151  and is a common electrode between the first light-emitting element  121  and the second light-emitting element  122 . 
     Meanwhile, the p-electrode  158  is provided on each mesa  153  and is an independent electrode for each of the first light-emitting element  121  and the second light-emitting element  122 . Therefore, when a voltage is applied between the p-electrode  158  and the n-electrode  159  provided in the first light-emitting element  121 , the first light-emitting element  121  can be caused to emit light. When a voltage is applied between the p-electrode  158  and the n-electrode  159  provided in the second light-emitting element  122 , the second light-emitting element  122  can be caused to emit light. Note that in the figures other than  FIG.  8   , illustration of the layer structure of the light-emitting element  150  is omitted and only the p-electrode  158  is illustrated. 
     Further, in the light-emitting element array  100 , an insulation layer  161  is provided on the light-emitting element surface  120 .  FIG.  9    is a cross-sectional view showing the insulation layer  161  on the first light-emitting element  121 , and  FIG.  10    is a plan view of the insulation layer  161  on the first light-emitting element  121 . As shown in these figures, a first through hole  161   a  is provided in the insulation layer  161  on the first light-emitting element  121 . The first through hole  161   a  penetrates the insulation layer  161  and exposes part of the p-electrode  158  of the first light-emitting element  121 . 
       FIG.  11    is a cross-sectional view showing the insulation layer  161  on the second light-emitting element  122 , and  FIG.  12    is a plan view of the insulation layer  161  on the second light-emitting element  122 . As shown in these figures, a second through hole  161   b  is provided in the insulation layer  161  on the second light-emitting element  122 . The second through hole  161   b  penetrates the insulation layer  161  and exposes part of the p-electrode  158  of the second light-emitting element  122 . Note that in  FIG.  1   ,  FIG.  2   , and  FIG.  5   , illustration of the insulation layer  161  is omitted. 
     The first wire  131  and the second wire  132  are each formed of a conductive material such as Au and are formed in the same layer as shown in  FIG.  3    and  FIG.  4   . Further, as shown in  FIG.  1    to  FIG.  4   , the first wire  131  and the second wire  132  extend in parallel to the light-emitting element surface (X-Y plane)  120  and are separated from each other. The first wire  131  and the second wire  132  each have regions overlapping with the first light-emitting element  121  and the second light-emitting element  122  as viewed from a direction (the Z direction) perpendicular to the light-emitting element surface  120 . 
     In  FIG.  2    to  FIG.  4   , the regions of the first wire  131  and the second wire  132  overlapping with the first light-emitting element  121  are shown as regions R 1 , and the regions of the first wire  131  and the second wire  132  overlapping with the second light-emitting element  122  are shown as regions R 2 . As shown in these figures, both the first wire  131  and the second wire  132  have the region R 1  and the region R 2 . The region R 1  and the region R 2  are formed on the outer periphery side than the p-electrode  158  so as not to shield the light-emitting surface S (see  FIG.  8   ). Further, the region R 1  and the region R 2  may be formed on the inner periphery side than the p-electrode  158  as long as the light-emitting surface S is not shielded. Further, in the case of prioritizing the increase in the width of the first wire  131  and the second wire  132 , the region R 1  and the region R 2  can be formed so as to partially shield the light-emitting surface S. 
     The first wire  131  is electrically connected to the first light-emitting element  121 , and the second wire  132  is electrically connected to the second light-emitting element  122 .  FIG.  13    is a cross-sectional view showing a connection relationship between the first light-emitting element  121  and the first wire  131  and the second wire  132 . As shown in the figure, the first wire  131  comes into contact with the p-electrode  158  of the first light-emitting element  121  via the first through hole  161   a  and is electrically connected to the p-electrode  158  of the first light-emitting element  121 . 
     Meanwhile, the second wire  132  is insulated from the p-electrode  158  of the first light-emitting element  121  by the insulation layer  161  provided between the second wire  132  and the p-electrode  158  of the first light-emitting element  121 . Similarly, also the other first light-emitting elements  121  included in the light-emitting element array  100  are each electrically connected to the first wire  131  and insulated from the second wire  132 . 
       FIG.  14    is a cross-sectional view showing a connection relationship between the second light-emitting element  122  and the first wire  131  and the second wire  132 . As shown in the figure, the second wire  132  comes into contact with the p-electrode  158  of the second light-emitting element  122  vis the second through hole  161   b  and is electrically connected to the p-electrode  158  of the second light-emitting element  122 . Meanwhile, the first wire  131  is insulated from the p-electrode  158  of the second light-emitting element  122  by the insulation layer  161  provided between the first wire  131  and the p-electrode  158  of the second light-emitting element  122 . Similarly, also the other second light-emitting elements  122  included in the light-emitting element array  100  are each electrically connected to the second wire  132  and insulated from the first wire  131 . 
     [Regarding Array of Light-Emitting Elements and Arrangement of Wires] 
     The array of the first light-emitting element  121  and the second light-emitting element  122  in the light-emitting element array  100  will be described.  FIG.  15    is a schematic diagram showing the array of the first light-emitting element  121  and the second light-emitting element  122 . 
     As shown in the figure, the first light-emitting elements  121  are arrayed along one direction (Y direction) in the light-emitting element surface  120  to form a plurality of light-emitting element columns L 1 . Further, the second light-emitting elements  122  are arrayed along a direction (Y direction) parallel to the light-emitting element column L 1  in the light-emitting element surface  120  to form a plurality of light-emitting element columns L 2 . The light-emitting element column L 1  and the light-emitting element column L 2  are alternately arranged and are separated from each other in a direction (X direction) orthogonal to the extending direction (Y direction). Further, the line connecting the centers of the first light-emitting elements  121  to each other is shown as a center C 1  of the light-emitting element column L 1 , and the line connecting the centers of the second light-emitting element  122  to each other is shown as a center C 2  of the light-emitting element column L 2 . 
       FIG.  16    and  FIG.  17    are each a schematic diagram showing the arrangement of the first wire  131  and the second wire  132 . As shown in  FIG.  16   , the first wire  131  and the second wire  132  are alternately provided between the center C 1  of the light-emitting element column L 1  and the center C 2  of the light-emitting element column L 2  as viewed from a direction (Z direction) perpendicular to the light-emitting element surface  120 , extend along the extending direction (Y direction) of the light-emitting element column L 1  and the light-emitting element column L 2 , and are separated from each other in a direction (X direction) orthogonal to the extending direction. 
     More specifically, as shown in  FIG.  17   , one of the light-emitting element columns L 1  is defined as a first light-emitting element column L 1   a,  and the light-emitting element column L 2  adjacent to the first light-emitting element column L 1   a  is defined as a second light-emitting element column L 2   b.  Further, the light-emitting element column L 1  provided on the side opposite to the first light-emitting element column L 1   a  with respect to the second light-emitting element column L 2   b  is defined as a third light-emitting element column L 1   c.    
     In this case, the first wire  131  is provided between the center C 1  of the first light-emitting element column L 1   a  and the center C 2  of the second light-emitting element column L 2   b  as viewed from the Z direction, and the second wire  132  is provided between the center C 2  of the second light-emitting element column L 2   b  and the center C 1  of the third light-emitting element column L 1   c  as viewed from the Z direction. Also the other first wires  131  and the other second wires  132  are arranged with respect to the light-emitting element columns L 1  and the light-emitting element columns L 2  such that a similar positional relationship is achieved. 
     Further, as shown in  FIG.  16   , the center of the first wire  131  is defined as a center P 1  and the center of the second wire  132  is defined as a center P 2 . The center P 1  is offset in the X direction with respect to the center C 1  as shown by an arrow A 1  and is separated from the center C 1 . The center P 2  is offset in the X direction with respect to the center C 2  as shown by an arrow A 2  and is separated from the center C 2 . 
     By arranging the first wire  131  and the second wire  132  in this way, it is possible to increase the widths of the first wire  131  and the second wire  132 .  FIG.  18    is a schematic diagram showing the widths of the first wire  131  and the second wire  132 . As shown in the figure, the minimum width of the first wire  131  in the X direction is defined as a width W 1  and the minimum width of the second wire  132  in the X direction is defined as a width W 2 . 
     Further, the interval between the first light-emitting element column L 1   a  and the second light-emitting element column L 2   b  in the X direction is defined as D 1  and the interval between the second light-emitting element column L 2   b  and the third light-emitting element column L 1   c  in the X direction is defined as D 2 . In this case, the width W 1  can be larger than the interval D 1  and the width W 2  can be larger than the interval D 2 . This can be realized by causing the first wire  131  and the second wire  132  to overlap with the first light-emitting element  121  and the second light-emitting element  122 , i.e., by forming the region R 1  and the region R 2  (see  FIG.  2   ). 
     [Effects of Light-Emitting Element Array] 
     The effects of the light-emitting element array  100  will be described as compared with Comparative Example.  FIG.  19    is a plan view of a light-emitting element array  300  according to a Comparative Example, and  FIG.  20    is a cross-sectional view of the light-emitting element array  300 .  FIG.  20    is a cross-sectional view taken along the line D-D in  FIG.  19   . 
     As shown in these figures, the light-emitting element array  300  includes a first light-emitting element  321 , a second light-emitting element  322 , a first wire  331 , and a second wire  332 . The first light-emitting element  321  and the second light-emitting element  322  are arrayed in a planar manner to form a light-emitting element surface  320 . The first light-emitting elements  321  and the second light-emitting elements  322  are each arrayed along one direction (Y direction) on the light-emitting element surface  320  to form a plurality of light-emitting element columns. 
     As shown in  FIG.  20   , the first wire  331  and the second wire  332  are formed on the light-emitting element surface  320  via an insulation layer  361 . As shown in  FIG.  19   , the first wire  331  extends on the column of the first light-emitting elements  321  and is electrically connected to a p-electrode  358  of the first light-emitting element  321  as shown in  FIG.  20   . As a result, the first light-emitting element  321  emits light by the drive current supplied from the first wire  331 . The first wire  331  is provided on the peripheral edge of the first light-emitting element  321  so as not to shield the light-emitting surface S on the first light-emitting element  321 . 
     As shown in  FIG.  19   , the second wire  332  extends on the column of the second light-emitting elements  322  and is electrically connected to the p-electrode  358  of the second light-emitting element  322 , similarly to the first wire  331 . As a result, the second light-emitting element  322  emits light by the drive current supplied from the second wire  332 . The second wire  332  is provided on the peripheral edge of the second light-emitting element  322  so as not to shield the light-emitting surface S on the second light-emitting element  322 . 
     with such a structure of the light-emitting element array  300 , since the first wire  331  and the second wire  332  do not shield the light-emitting surface S and it is necessary to maintain the interval between adjacent wires in order to prevent a short circuit, it is difficult to increase the width of the wire. For this reason, when the number of arrays of light-emitting elements increases or the density of light-emitting elements increases, the influence of the wiring resistance becomes large and a problem that the amount of light emitted on the downstream side of the wire decreases occurs. Further, it is not easy to increase the thickness of the wire from the viewpoint of the production process. 
     By providing a multilayer structure of the first wire  331  and the second wire  332  via an insulation layer instead of forming these layers in the same layer, it is possible to increase the width of the wire but the production process is complicated. Further, in the case of providing a multilayer structure, there is a problem that the light-emitting properties vary due to the increased thickness of the insulation layer on the light-emitting element. 
     Meanwhile, in the light-emitting element array  100 , the first wire  131  and the second wire  132  are arranged so as to overlap with the first light-emitting element  121  and the second light-emitting element  122  (see  FIG.  2   ). As a result, it is possible to increase the widths of the wires while forming the first wire  131  and the second wire  132  in the same layer and suppress the wiring resistance of the first wire  131  and the second wire  132 . 
     Further, in the case of making the widths of the first wire  131  and the second wire  132  the same as those in the Comparative Example, it is possible to bring the light-emitting elements and the wirings closer to each other and improve the density thereof. Further, since the first wire  131  and the second wire  132  are in the same layer, the production process is not complicated and it is possible to suppress the influence on the light-emitting properties. 
     [Regarding Groove Structure] 
     The light-emitting element array  100  may include groove portions for the first wire  131  and the second wire  132  in addition to the configuration described above.  FIG.  21    is a plan view of the light-emitting element array  100  including a groove portion, and  FIG.  22    is an enlarged view of  FIG.  21   .  FIG.  23    is a cross-sectional view of this light-emitting element array  100  and is a cross-sectional view taken along the line E 1  to E 4  in  FIG.  22   . 
       FIG.  24    is a plan view of this light-emitting element array  100  in which illustration of the first wire  131  and the second wire  132  is omitted. As shown in the figure, a first groove portion  171  that connects between the recessed portions  152  (see  FIG.  8   ) of the first light-emitting element  121  and a second groove portion  172  that connects between the recessed portions  152  (see  FIG.  8   ) of the second light-emitting element  122  are provided in the substrate  151 . As shown in  FIG.  24   , the first groove portion  171  may be connected also to the recessed portion  152  of the second light-emitting element  122  and does not necessarily need to be connected thereto. Further, the second groove portion  172  may be connected to the recessed portion  152  of the first light-emitting element  121  and does not necessarily need to be connected thereto. 
     As shown in  FIG.  23   , the first wire  131  is formed in the first groove portion  171  continuously from the recessed portion  152  of the first light-emitting element  121  and is continuous with the recessed portion  152  of the adjacent first light-emitting element. Similarly, also the second wire  132  is formed in the second groove portion  172  continuously from the recessed portion  152  of the second light-emitting element  122  and is continuous with the recessed portion  152  of the adjacent second light-emitting element. 
     As a result, the thickness of each of the first wire  131  and the second wire  132  increases as compared with the case where the first groove portion  171  and the second groove portion  172  are not provided, and it is possible to further suppress the wiring resistance and contribute to the increase in the density of light-emitting elements and wires. 
     [Modified Example] 
     Although the p-electrode  158  has an annular shape (see  FIG.  7   ) as described above, the p-electrode  158  may have another shape.  FIG.  25    to  FIG.  31    are each a schematic diagram showing another shape of the p-electrode  158 . The p-electrode  158  may have a rectangular annular shape as viewed from a direction (Z direction) perpendicular to the light-emitting element surface  120  as shown in  FIG.  25   , or may have a hexagonal annular shape as viewed from the Z direction as shown in  FIG.  26   . Further, the p-electrode  158  may have a polygonal shape or another annular shape as viewed from the Z direction. 
     Further, as shown in  FIG.  27   , the p-electrode  158  may have a C-shape as viewed from a direction (Z direction) perpendicular to the light-emitting element surface  120  or may have various annular shapes from which part thereof is missing. Further, the p-electrode  158  may have a pair of arc shapes facing each other as viewed from the Z direction as shown in  FIG.  28    or may have a pair of linear shapes facing each other as viewed from the Z direction as shown in  FIG.  29   . 
     Further, the p-electrode  158  may have one arc shape as viewed from the Z direction as shown in  FIG.  30    or may have one linear shape as viewed from the Z direction as shown in  FIG.  31   . In the case of the shapes shown in  FIG.  30    and  FIG.  31   , the p-electrode  158  is provided at a position overlapping with the first wire  131  or the second wire  132  to be connected (see  FIG.  3    and  FIG.  4   ) as viewed from the Z direction. In addition to the above, the p-electrode  158  may have various shapes. 
     Further, although the light-emitting element  150  has been described to include the mesa  153  having a cylindrical shape (see  FIG.  7   ), the shape of the mesa  153  is not limited to a cylindrical shape.  FIG.  32    to  FIG.  34    are each a schematic diagram showing another shape of the mesa  153 . 
     The mesa  153  may have a hexagonal column shape as shown in  FIG.  32    or may have an octagonal column shape as shown in  FIG.  33   . Further, the mesa  153  may have a quadrangular column shape as shown in  FIG.  34   . In addition, the mesa  153  can have a polygonal column shape including a pentagonal column shape and a heptagonal column shape, or another columnar shape. 
     Further, although the first wire  131  and the second wire  132  have been described to be formed in the recessed portion  152  (see  FIG.  13   ) together with the insulation layer  161 , the present technology is not limited thereto.  FIG.  35    is a schematic diagram showing another configuration in the recessed portion  152 . As shown in the figure, an embed material  162  may be embedded in the recessed portion  152  and may be covered with an insulation film  163 . The first wire  131  and the second wire  132  can be formed on the insulation film  163 . Further, in the case where the embed material  162  is formed of an insulating material, the insulation film  163  does not need to be provided. 
     Further, in the case where the embed material  162  is formed of a metal material, the embed material  162  may be used as the first wire  131  or the second wire  132  without providing the insulation film  163 . However, in this case, the embed material  162  can be used as only one of the first wire  131  and the second wire  132 , and the other wire needs to be provided on the insulation film  163 . 
     Further, although the first wire  131  and the second wire  132  have been described to be alternately arranged (see  FIG.  1   ), the present technology is not limited thereto.  FIG.  36    and  FIG.  37    are each a schematic diagram showing another arrangement of the first wire  131  and the second wire  132 . The first wire  131  and the second wire  132  may be arranged as shown in these figures. As shown in  FIG.  36    and  FIG.  37   , the plurality of first wire  131  is adjacent to each other, the plurality of adjacent first wires  131  may be used as one first wire  131 . Similarly, in the case where the plurality of second wires  132  is adjacent to each other, the plurality of adjacent second wires  132  may be used as one second wire  132 . 
     Further, although the light-emitting element column L 1  and the light-emitting element column L 2  have been described as a linear column extending in the Y direction, the present technology is not limited thereto. The light-emitting element column L 1  and the light-emitting element column L 2  may extend in a curved shape, a spiral shape, a comb tooth shape, or the like. Also in this case, the first wire  131  and the second wire  132  each have the regions R 1  and R 2  (see  FIG.  2   ) overlapping with the first light-emitting element  121  and the second light-emitting element  122  and make it possible to increase the density of light-emitting elements and wires. 
     [Usage Example of Light-Emitting Element Array] 
     The light-emitting element array  100  can be used for a distance measurement light source device or the like capable of emitting short-distance light and long-distance light because the first light-emitting element  121  and the second light-emitting element  122  can be caused to independently emit light as described above. 
     [Regarding Third Light-Emitting Element and Fourth Light-Emitting Element] 
     As described above, the light-emitting element group constituting the light-emitting element array  100  includes the first light-emitting element  121  and the second light-emitting element  122 . Further, the light-emitting element group constituting the light-emitting element array  100  can include a third light-emitting element  123  and a fourth light-emitting element  124 .  FIG.  38    is a plan view of the light-emitting element array  100  that includes the third light-emitting element  123  and the fourth light-emitting element  124 . 
     As shown in the figure, the third light-emitting elements  123  are arrayed along one direction in the light-emitting element surface  120  to form a plurality of light-emitting element columns L 3 . Further, the fourth light-emitting elements  124  are arrayed along a direction parallel to the light-emitting element column L 3  in the light-emitting element surface  120  to form a plurality of light-emitting element columns L 4 . The light-emitting element column L 3  and the light-emitting element column L 4  are alternately arranged and are separated from each other in a direction orthogonal to the extending direction. 
       FIG.  39    is a schematic diagram showing a relationship between the light-emitting element column L 1  and the light-emitting element column L 2  and the light-emitting element column L 3  and the light-emitting element column L 4 . As shown in  FIG.  39   , the light-emitting element column L 3  and the light-emitting element column L 4  extend in a direction (X direction) orthogonal to the extending direction (Y direction) of the light-emitting element column L 1  and the light-emitting element column L 2 . Therefore, the third light-emitting elements  123  include some of the first light-emitting elements  121  and some of the second light-emitting elements  122 , and the fourth light-emitting elements  124  include the others of the first light-emitting element  121  and the others of the second light-emitting element  122 . 
     The first light-emitting element  121  and the second light-emitting element  122  are defined by whether the wire connected to the p-side (see  FIG.  8   ) of each light-emitting element  150  is the first wire  131  or the second wire  132  as described above. Meanwhile, the third light-emitting element  123  and the fourth light-emitting element  124  are defined by the wire connected to the n-side of each light-emitting element  150  as described below. The wiring structure on this n-side will be described below. 
     [Wiring Structure  1  on N-Side] 
     Although the n-electrode  159  has been provided on the surface of the substrate  151  on the side opposite to the light-emitting element  150  (see  FIG.  8   ) and the electrical connection has been made on the n-side of the light-emitting element  150  via the n-electrode  159  in the light-emitting element array  100  in the above description, the electrical connection on the n-side can be made as follows. 
       FIG.  40    is a plan view showing a wiring structure on the n-side of the light-emitting element array  100 , and  FIG.  41    is an enlarged view of  FIG.  40   .  FIG.  42    is a cross-sectional view of the light-emitting element array  100  and is a cross-sectional view taken along the line E-E in  FIG.  41   . As shown in these figures, the light-emitting element array  100  includes a third wire  133  and a fourth wire  134  as n-side wires. Note that in  FIG.  40    to  FIG.  42   , illustration of a partial configuration such as the p-electrode  158 , the first wire  131 , and the second wire  132  is omitted. 
     As shown in  FIG.  41    and  FIG.  42   , the third light-emitting element  123  and the fourth light-emitting element  124  each have a mesa structure in which the mesa (plateau shape)  153  is formed by being surrounded by the recessed portion  152  provided in the substrate  151 . The recessed portion  152  has a bottom surface  125  that is separated from the light-emitting element surface  120  (see  FIG.  6   ) and is parallel to the light-emitting element surface  120 . 
     As shown in  FIG.  42   , the bottom surface  125  is a surface formed by an n-contact layer  164 . The re-contact layer  164  is formed of an n-type semiconductor material and is provided adjacent to the n-type DBR layer  154  on the substrate  151  side of the n-type DBR layer  154 . An element isolation groove  165  is provided in the bottom surface  125 . As shown in  FIG.  40   , the element isolation groove  165  is provided between the light-emitting element column L 3  and the light-emitting element column L 4  and extend along the extending direction of the light-emitting element column L 3  and the light-emitting element column L 4 . The element isolation groove  165  has a depth at which at least the n-contact layer  164  can be separated and electrically separates the third light-emitting element  123  and the fourth light-emitting element  124  from each other by separating the n-contact layer  164 . 
     The third wire  133  and the fourth wire  134  are each formed of a conductive material such as Au and is formed on the bottom surface  125 . Specifically, the third wire  133  is provided between the element isolation grooves  165  and around the third light-emitting element  123  as viewed from a direction (Z direction) perpendicular to the bottom surface  125  and extends along the extending direction (X direction) of the light-emitting element column L 3 . Further, the fourth wire  134  is provided between the element isolation grooves  165  and around the fourth light-emitting element  124  as viewed from a direction (Z direction) perpendicular to the bottom surface  125  and extends along the extending direction (X direction) of the light-emitting element column L 4 . 
     By making the third wire  133  and the fourth wire  134  have the configuration as described above, it is possible to switch the light-emitting element  150  that emits light. Specifically, by applying a voltage between the first wire  131  and the third wire  133 , it is possible to cause the light-emitting element  150  (see  FIG.  39   ) included in both the light-emitting element column L 1  and the light-emitting element column L 3  to emit light. 
     Further, by applying a voltage between the first wire  131  and the fourth wire  134 , it is possible to cause the light-emitting element  150  included in both the light-emitting element column L 1  and the light-emitting element column L 4  to emit light. Similarly, by applying a voltage between the second wire  132  and the third wire  133 , it is possible to cause the light-emitting element  150  included in both the light-emitting element column L 2  and the light-emitting element column L 3  to emit light. Further, by applying a voltage between the second wire  132  and the fourth wire  134 , it is possible to cause the light-emitting element  150  included in both the light-emitting element column L 2  and the light-emitting element column L 4  to emit light. 
     Here, the widths of the third wire  133  and the fourth wire  134  will be examined. As shown in  FIG.  41   , the minimum width of the third wire  133  in the Y direction is defined as a width W 3  and the minimum width of the fourth wire  134  in the Y direction is defined as a width W 4 . By making the width W 3  and the width W 4  wider, the wiring resistance of the third wire  133  and the fourth wire  134  can be reduced. Meanwhile, when the width W 3  and the width W 4  are widened, the density of light-emitting elements decreases and the light emission intensity of the light-emitting element array  100  is reduced. Hereinafter, a configuration the width W 3  and the width W 4  are widened while maintaining the density of light-emitting elements will be described. 
     Note that the structure described above can be formed by etching the mesa  153  up to the n-contact layer  164  by RIE (Reactive Ion Etching). After that, the mesa  153  is covered with the insulation layer  161  and the insulation layer  161  around the mesa  153  is further opened by RIE. As a result, the bottom surface  125  is exposed, so that the third wire  133  and the fourth wire  134  can be formed on the bottom surface  125 . 
     [Wiring Structure  2  on N-Side] 
     Another example of the wiring structure on the n-side of the light-emitting element array  100  will be described.  FIG.  43    is a plan view showing this wiring structure, and  FIG.  44    is an enlarged view of  FIG.  43   .  FIG.  45    is a cross-sectional view of the light-emitting element array  100 , and is a cross-sectional view taken along the line F-F in  FIG.  44   . Note that in  FIG.  43    to  FIG.  45   , illustration of a partial configuration such as the p-electrode  158 , the first wire  131 , and the second wire  132  is omitted. As shown in  FIG.  43    and  FIG.  44   , the third wire  133  and the fourth wire  134  are each arranged between the light-emitting element column L 3  and the light-emitting element column L 4 . Further, as shown in  FIG.  45   , the third wire  133  and the fourth wire  134  are provided on the bottom surface  125  and the element isolation groove  165 . 
       FIG.  46    is a plan view showing the bottom surface  125 , and  FIG.  47    is a cross-sectional view taken along the line G-G in  FIG.  46   . As shown in these figures, a region of the bottom surface  125  between the element isolation groove  165  and the third light-emitting element  123  is defined as a region R 3 . Further, a region of the bottom surface  125  between the element isolation groove  165  and the fourth light-emitting element  124  is defined as a region R 4 . 
     As shown in  FIG.  45   , the insulation layer  161  is provided in the element isolation groove  165  and on the bottom surface  125 .  FIG.  48    is a plan view showing the insulation layer  161 , and  FIG.  49    is a cross-sectional view taken along the line H-H in  FIG.  48   . As shown in  FIG.  48    and  FIG.  49   , A first opening  161   c  that is an opening of the insulation layer  161  is provided on one of the regions R 3  (see  FIG.  47   ) on both sides of the third light-emitting element  123 . Further, as shown in  FIG.  48    and  FIG.  49   , a second opening  161   d  that is an opening of the insulation layer  161  is provided on one of the regions R 4  (see  FIG.  47   ) on both sides of the fourth light-emitting element  124 . 
     As shown in  FIG.  44    and  FIG.  45   , the third wire  133  is provided on the insulation layer  161  and in the element isolation groove  165 , which are provided on the bottom surface  125 , and overlaps with the region R 3 , the region R 4 , and the element isolation groove  165  as viewed from a direction (Z direction) perpendicular to the bottom surface  125 . The third wire  133  comes into contact with the n-contact layer  164  of the third light-emitting element  123  via the first opening  161   c  provided on the region R 3  and is electrically connected to the n-contact layer  164  of the third light-emitting element  123 . Further, the third wire  133  is insulated from the n-contact layer  164  of the fourth light-emitting element  124  by the insulation layer  161  on the region R 4 . 
     Further, as shown in  FIG.  44    and  FIG.  45   , the fourth wire  134  is provided on the insulation layer  161  and in the element isolation groove  165 , which are provide on the bottom surface  125 , and overlaps with the region R 3 , the region R 4 , and the element isolation groove  165  as viewed from a direction (Z direction) perpendicular to the bottom surface  125 . The fourth wire  134  comes into contact with the n-contact layer  164  of the fourth light-emitting element  124  via the second opening  161   d  provided on the region R 4  and is electrically connected to the n-contact layer  164  of the fourth light-emitting element  124 . Further, the fourth wire  134  is insulated from the n-contact layer  164  of the third light-emitting element  123  by the insulation layer  161  on the region R 3 . 
     In this structure, as shown in  FIG.  44   , the minimum width W 3  of the third wire  133  in the Y direction and the minimum width W 4  of the fourth wire  134  in the Y direction can be widened while maintaining the density of light-emitting elements. As a result, it is possible to reduce the wiring resistance of the third wire  133  and the fourth wire  134 . 
     Note that the structure described above can be formed by etching the mesa  153  up to the n-contact layer  164  by RIE. After that, the mesa  153  is covered with the insulation layer  161 , and the first opening  161   c  and the second opening  161   d  are formed by RIE. As a result, it is possible to form the third wire  133  on the first opening  161   c  and the insulation layer  161  and form the fourth wire  134  on the second opening  161   d  and the insulation layer  161 . 
     [Wiring Structure  3  on N-Side] 
     Another example of the wiring structure of the light-emitting element array  100  on the n-side will be described.  FIG.  50    is a plan view showing this wiring structure, and  FIG.  51    is an enlarged view of  FIG.  50   . The cross-sectional view taken along the line I-I of this light-emitting element array  100  is the same as that in  FIG.  45   . Note that in  FIG.  50    and  FIG.  51   , illustration of a partial configuration such as the p-electrode  158 , the first wire  131 , and the second wire  132  is omitted. As shown in these figures, the third wire  133  and the fourth wire  134  are different from the third wire  133  and the fourth wire  134  (see  FIG.  43   ) shown in the wiring structure  2  in the separation positions of the wires. 
       FIG.  52    is a plan view showing the shapes of the third wire  133  and the fourth wire  134 . As shown in the figure, when the width of the third wire  133  in the Y direction from the element isolation groove  165  to the third light-emitting element  123  side is defined as a width K 1  and the width of the third wire  133  in the Y direction from the element isolation groove  165  to the fourth light-emitting element  124  side is defined as a width K 2 , the width K 1  is larger than the width K 2 . Further, the width of the fourth wire  134  in the Y direction from the element isolation groove  165  to the fourth light-emitting element  124  side is defined as a width K 3  and the width of the fourth wire  134  in the Y direction from the element isolation groove  165  to the third light-emitting element  123  side is defined as a width K 4 , the width K 3  is larger than the width K 4 . 
     By forming the third wire  133  and the fourth wire  134  in such shapes, the opening areas of the first opening  161   c  and the second opening  161   d  can be increased as shown in  FIG.  51    while the minimum width W 3  of the third wire  133  and the minimum width W 4  of the fourth wire  134  are the same as those in the wiring structure  2 . As a result, it is possible to reduce the contact resistance between the third wire  133  and the n-contact layer  164  of the third light-emitting element  123 , which are in contact with each other via the first opening  161   c.  Further, it is possible to reduce the contact resistance between the fourth wire  134  and the n-contact layer  164  of the fourth light-emitting element  124 , which are in contact with each other via the second opening  161   d.    
     [Modified Example] 
     Although the light-emitting element column L 3  and the light-emitting element column L 4  have extent in a direction (X direction) orthogonal to the extending direction (Y direction) of the light-emitting element column L 1  and the light-emitting element column L 2  in the above description (see  FIG.  39   ), the extending direction of the light-emitting element column L 3  and the light-emitting element column L 4  is not limited thereto.  FIG.  53    is a schematic diagram showing another extending direction of the light-emitting element column L 3  and the light-emitting element column L 4 . As shown in the figure, the extending direction of the light-emitting element column L 3  and the light-emitting element column L 4  can be the Y direction that is the same as the extending direction of the light-emitting element column L 1  and the light-emitting element column L 2 . In this case, the third light-emitting element  123  coincides with the first light-emitting element  121  and the fourth light-emitting element  124  coincides with the second light-emitting element  122 . 
     By making the third wire  133  and the fourth wire  134  have the configuration as described above, the light-emitting element  150  included in the light-emitting element column L 1  (same as the light-emitting element column L 3 ) can be caused to emit light by applying a voltage between the first wire  131  and the third wire  133 . By applying a voltage between the second wire  132  and the fourth wire  134 , the light-emitting element  150  included in the light-emitting element column L 2  (same as the light-emitting element column L 4 ) can be caused to emit light. In addition, the extending direction of the light-emitting element column L 3  and the light-emitting element column L 4  can be any direction parallel to the X-Y plane. 
     Further, in the light-emitting element array  100  described above, the first wire  131  and the second wire  132  that are p-side wires have had a configuration according to the present technology (see  FIG.  2   ) and the third wire  133  and the fourth wire  134  that are n-side wires also have had a configuration according to the present technology (see  FIG.  45   ). Here, in the light-emitting element array  100 , both the wires on the p-side and the n-side do not necessarily need to have a configuration according to the present technology. That is, in the light-emitting element array  100 , only the p-side wire may have a configuration according to the present technology and the n-side wire may have a general wiring structure in a light-emitting element array. Further, in the light-emitting element array  100 , only the n-side wire may have a configuration according to the present technology and the p-side wire may have a general wiring structure in a light-emitting element array. 
     Note that although the first wire  131  and the second wire  132  have been the p-side wires and the third wire  133  and the fourth wire  134  have been the n-side wires in the above description, the n-type and the p-type in the light-emitting element  150  may be reversed. In this case, the first wire  131  and the second wire  132  are n-side wires and the third wire  133  and the fourth wire  134  are p-side wires. 
     [Regarding Present Disclosure] 
     The effects described in the present disclosure are merely examples and are not limited, and additional effects may be exerted. The description of the plurality of effects described above does not necessarily mean that these effects are exerted at the same time. It means that at least one of the effects described above can be achieved and there is a possibility that an effect that is not described in the present disclosure is exerted. Further, at least two feature parts of the feature parts described in the present disclosure may be arbitrarily combined with each other. 
     It should be noted that the present technology may also take the following configurations.
     (1) A light-emitting element array, including:   

     a light-emitting element group that includes a plurality of first light-emitting elements and a plurality of second light-emitting elements that are arrayed in a planar manner to form a light-emitting element surface; 
     a first wire that extends in a direction parallel to the light-emitting element surface, has a region overlapping with the plurality of first light-emitting elements and a region overlapping with the plurality of second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, is electrically connected to the plurality of first light-emitting elements, and is not electrically connected to the plurality of second light-emitting elements; and 
     a second wire that extends in a direction parallel to the light-emitting element surface, has a region overlapping with the plurality of first light-emitting elements and a region overlapping with the plurality of second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, is electrically connected to the plurality of second light-emitting elements, and is not electrically connected to the plurality of first light-emitting elements.
     (2) The light-emitting element array according to (1) above, in which   

     the light-emitting element group includes a first light-emitting element column in which the plurality of first light-emitting elements is arrayed, and a second light-emitting element column in which the plurality of second light-emitting elements is arrayed, 
     a center of the first wire is separated from a center of the first light-emitting element column in a direction parallel to the light-emitting element surface, and 
     a center of the second wire is separated from a center of the second light-emitting element column in a direction parallel to the light-emitting element surface.
     (3) The light-emitting element array according to (2) above, in which   

     the light-emitting element group further includes a third light-emitting element column in which the plurality of first light-emitting elements is arrayed, the third light-emitting element column being provided on a side opposite to the first light-emitting element column with respect to the second light-emitting element column, 
     the first wire is provided between the center of the first light-emitting element column and the center of the second light-emitting element column as viewed from a direction perpendicular to the light-emitting element surface, and 
     the second wire is provided between the center of the second light-emitting element column and a center of the third light-emitting element column as viewed from a direction perpendicular to the light-emitting element surface.
     (4) The light-emitting element array according to (3) above, in which   

     the first light-emitting element column, the second light-emitting element column, the third light-emitting element column, the first wire, and the second wire extend in a first direction parallel to the light-emitting element surface and are separated from each other in a second direction that is parallel to the light-emitting element surface and orthogonal to the first direction, 
     a width of the first wire in the second direction is larger than an interval between the first light-emitting element column and the second light-emitting element column in the second direction, and 
     a width of the second wire in the second direction is larger than an interval between the second light-emitting element column and the third light-emitting element column in the second direction.
     (5) The light-emitting element array according to any one of (1) to (4) above, in which   

     the first wire and the second wire are formed in a same layer.
     (6) The light-emitting element array according to (5) above, in which   

     the first wire is stacked on the plurality of first light-emitting elements and the plurality of second light-emitting elements via an insulation layer, is electrically connected to the plurality of first light-emitting elements via a first through hole provided in the insulation layer on the plurality of first light-emitting elements, and is insulated from the plurality of second light-emitting elements by the insulation layer on the plurality of second light-emitting elements, and 
     the second wire is stacked on the plurality of first light-emitting elements and the plurality of second light-emitting elements via the insulation layer, is electrically connected to the plurality of second light-emitting elements via a second through hole provided in the insulation layer on the plurality of second light-emitting elements, and is insulated from the plurality of first light-emitting elements by the insulation layer on the plurality of first light-emitting elements.
     (7) The light-emitting element array according to (6) above, in which   

     the plurality of first light-emitting elements is each a vertical cavity surface emitting laser element and includes a first light-emitting surface and a first electrode provided around the first light-emitting surface, 
     the plurality of second light-emitting elements is each a vertical cavity surface emitting laser element and includes a second light-emitting surface and a second electrode provided around the second light-emitting surface, 
     the first wire abuts on the first electrode via the first through hole in the plurality of first light-emitting elements, and 
     the second wire abuts on the second electrode via the second through hole in the plurality of second light-emitting elements.
     (8) The light-emitting element array according to any one of (1) to (7) above, in which   

     the plurality of first light-emitting elements and the plurality of second light-emitting elements each have a mesa structure surrounded by a recessed portion, 
     the light-emitting element group includes a first groove portion that connects the recessed portions to each other between the plurality of first light-emitting elements and a second groove portion that connects the recessed portions to each other between the plurality of second light-emitting elements, 
     the first wire may have a portion formed in the first groove portion, and 
     the second wire may have a portion formed in the second groove portion.
     (9) The light-emitting element array according to any one of (1) to (8) above, in which   

     the light-emitting elements constituting the light-emitting element group include a plurality of third light-emitting elements and a plurality of fourth light-emitting elements, the plurality of third light-emitting elements and the plurality of fourth light-emitting elements each having a mesa structure surrounded by a recessed portion, the recessed portion being separated from the light-emitting element surface and having a bottom surface parallel to the light-emitting element surface, an element isolation groove that electrically separates the plurality of third light-emitting elements and the plurality of fourth light-emitting elements from each other being provided in the bottom surface, 
     the light-emitting element array further including:
         a third wire that extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the third light-emitting element and a region of the bottom surface between the element isolation groove and the fourth light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the third light-emitting element, and is not electrically connected to the fourth light-emitting element; and   a fourth wire that extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the third light-emitting element and a region of the bottom surface between the element isolation groove and the fourth light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the fourth light-emitting element, and is not electrically connected to the third light-emitting element.       (10) The light-emitting element array according to (9) above, in which   

     the light-emitting element group includes a first light-emitting element column in which the plurality of first light-emitting elements is arrayed, a second light-emitting element column in which the plurality of second light-emitting elements is arrayed, a third light-emitting element column in which the plurality of third light-emitting elements is arrayed, and a fourth light-emitting element column in which the plurality of fourth light-emitting elements is arrayed.
     (11) The light-emitting element array according to (10) above, in which   

     the first light-emitting element column, the second light-emitting element column, the first wire, and the second wire each extend in a first direction parallel to the light-emitting element surface, and 
     the third light-emitting element column, the fourth light-emitting element column, the third wire, and the fourth wire each extend in a second direction that is parallel to the light-emitting element surface and is orthogonal to the first direction.
     (12) The light-emitting element array according to (10) above, in which   

     the first light-emitting element column, the second light-emitting element column, the first wire, and the second wire each extend in a first direction parallel to the light-emitting element surface, and 
     the third light-emitting element column, the fourth light-emitting element column, the third wire, and the fourth wire each extend in the first direction.
     (13) The light-emitting element array according to any one of (9) to (12) above, in which   

     the third wire is stacked on the bottom surface and the element isolation groove via an insulation layer, is electrically connected to the plurality of third light-emitting elements via a first opening provided in the insulation layer in a region of the bottom surface between the element isolation groove and the third light-emitting element, and is insulated from the plurality of fourth light-emitting elements by the insulation layer in a region of the bottom surface between the element isolation groove and the fourth light-emitting element, and 
     the fourth wire is stacked on the bottom surface and the element isolation groove via the insulation layer, is electrically connected to the plurality of fourth light-emitting elements via a second opening provided in the insulation layer in a region of the bottom surface between the element isolation groove and the fourth light-emitting element, and is insulated from the plurality of third light-emitting elements by the insulation layer in a region of the bottom surface between the element isolation groove and the third light-emitting element.
     (14) The light-emitting element array according to any one of (9) to (13) above, in which   

     the third wire has a width from the element isolation groove to a side of the third light-emitting element larger than a width from the element isolation groove to a side of the fourth light-emitting element, and 
     the fourth wire has a width from the element isolation groove to a side of the fourth light-emitting element larger than a width from the element isolation groove to a side of the third light-emitting element.
     (15) A light-emitting element array, including:   

     a light-emitting element group in which a plurality of first light-emitting elements and a plurality of second light-emitting elements are arrayed in a planar manner to form a light-emitting element surface, the plurality of first light-emitting elements and the plurality of second light-emitting elements each having a mesa structure surrounded by a recessed portion, the recessed portion being separated from the light-emitting element surface and having a bottom surface parallel to the light-emitting element surface, an element isolation groove that electrically separates the plurality of first light-emitting elements and the plurality of second light-emitting elements from each other being provided in the bottom surface. 
     a first wire that extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the first light-emitting element and a region of the bottom surface between the element isolation groove and the second light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the first light-emitting element, and is not electrically connected to the second light-emitting element; 
     a second wire that extends in a direction parallel to the bottom surface, has a region of the bottom surface between the element isolation groove and the first light-emitting element and a region of the bottom surface between the element isolation groove and the second light-emitting element as viewed from a direction perpendicular to the bottom surface, overlaps with the element isolation groove, is electrically connected to the second light-emitting element, and is not electrically connected to the first light-emitting element. 
     REFERENCE SIGNS LIST 
       100  light-emitting element array 
       120  light-emitting element surface 
       121  first light-emitting element 
       122  second light-emitting element 
       123  third light-emitting element 
       124  fourth light-emitting element 
       125  bottom surface 
       131  first wire 
       132  second wire 
       133  third wire 
       134  fourth wire 
       150  light-emitting element 
       151  substrate 
       152  recessed portion 
       153  mesa 
       154  n-type DBR layer 
       155  active layer 
       156  current confinement layer 
       157  p-type DBR layer 
       158  p-electrode 
       159  n-electrode 
       161  insulation layer 
       161   a  first through hole 
       161   b  second through hole 
       161   c  first opening 
       161   d  second opening 
       164  n-contact layer 
       165  element isolation groove 
       171  first groove portion 
       172  second groove portion