LIGHT-EMITTING ELEMENT ARRAY

[Object] To provide a light-emitting element array having a wiring structure that enables an increase in response speed of a light-emitting element. [Solving Means] A light-emitting element array according to the present technology includes: a light-emitting element group; a first wire; and a second wire. The light-emitting element group forms a light-emitting element surface on which a plurality of light-emitting elements is arranged in a planar shape and includes first light-emitting element columns, first light-emitting elements included in the plurality of light-emitting elements being arranged along a first direction parallel to the light-emitting element surface in each of the first light-emitting element columns. The first wire extends along the first direction and is electrically connected to each of the first light-emitting elements in each of the first light-emitting element columns, a current flowing through the first wire in a first orientation parallel to the first direction. The second wire extends along the first direction and is electrically connected to each of the first light-emitting elements in each of the first light-emitting element columns, a current flowing through the second wire in a second orientation parallel to the first direction and opposite to the first orientation.

TECHNICAL FIELD

The present technology relates to a light-emitting element array in which a plurality of light-emitting elements is arranged.

BACKGROUND ART

A light-emitting element such as a vertical cavity surface emitting laser (VCSEL) element is often used for a light-emitting element array in which a plurality of light-emitting elements is arranged. 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 a semiconductor near-field light source in which a row wire and a column wire are connected to each of a large number of light-emitting elements arranged in a matrix. The row wire and the column wire extend in directions perpendicular to each other and are provided to intersect with each other. By applying a voltage to an arbitrary row wire and an arbitrary column wire, the light-emitting element located at the intersection of the row wire and the column wire to which the voltage is applied emits light.

CITATION LIST

Patent Literature

DISCLOSURE OF INVENTION

Technical Problem

However, in the light-emitting element array as described in Patent Literature 1, a decrease in response speed of the light-emitting element becomes a problem. In particular, in sensing applications, the response speed of the light-emitting element is an important parameter and is desired to be improved.

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 that enables an increase in response speed of a light-emitting element.

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 forms a light-emitting element surface on which a plurality of light-emitting elements is arranged in a planar shape and includes first light-emitting element columns, first light-emitting elements included in the plurality of light-emitting elements being arranged along a first direction parallel to the light-emitting element surface in each of the first light-emitting element columns.

The first wire extends along the first direction and is electrically connected to each of the first light-emitting elements in each of the first light-emitting element columns, a current flowing through the first wire in a first orientation parallel to the first direction.

The second wire extends along the first direction and is electrically connected to each of the first light-emitting elements in each of the first light-emitting element columns, a current flowing through the second wire in a second orientation parallel to the first direction and opposite to the first orientation.

The light-emitting element group may further include second light-emitting element columns, second light-emitting elements included in the plurality of light-emitting elements being arranged along a second direction parallel to the light-emitting element surface in each of the second light-emitting element columns, and the light-emitting element array may further include:a third wire that extends along the second direction and is electrically connected to each of the second light-emitting elements in each of the second light-emitting element columns, a current flowing through the third wire in a third orientation parallel to the second direction; anda fourth wire that extends along the second direction and is electrically connected to each of the second light-emitting elements in each of the second light-emitting element columns, a current flowing through the fourth wire in a fourth orientation parallel to the second direction and opposite to the third orientation.

The first direction and the second direction may be orthogonal to each other.

The light-emitting element array may further include:a first insulation layer formed of an insulating material; anda second insulation layer formed of an insulating material,the first insulation layer being disposed on the light-emitting element surface,the first wire and the second wire being disposed on the first insulation layer,the second insulation layer being formed on the first insulation layer, the first wire, and the second wire,the third wire and the fourth wire being disposed on the second insulation layer.

The first wire may be electrically connected to each of the first light-emitting elements via a first current injection port provided in the first insulation layer,the second wire may be electrically connected to each of the first light-emitting elements via a second current injection port provided in the first insulation layer,the third wire may be electrically connected to each of the second light-emitting elements via a third current injection port provided in the first insulation layer and the second insulation layer, andthe fourth wire may be electrically connected to each of the second light-emitting elements via a fourth current injection port provided in the first insulation layer and the second insulation layer.

The first wire may have a first superimposition region that is superimposed on the first light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the first current injection port being provided within the first superimposition region as viewed from the direction,the second wire may have a second superimposition region that is superimposed on the first light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the second current injection port being provided within the second superimposition region as viewed from the direction,the third wire may have a third superimposition region that is superimposed on the second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the third current injection port being provided within the third superimposition region as viewed from the direction, andthe fourth wire may have a fourth superimposition region that is superimposed on the second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the fourth current injection port being provided within the fourth superimposition region as viewed from the direction.

The light-emitting element array may further includea first electrode pad that is electrically connected to the first wire and the second wire and includes a first portion and a second portion, the first portion and the second portion being located in opposite directions via the light-emitting element group in the first direction,the first wire being connected to the first portion and spaced apart from the second portion,the second wire being connected to the second portion and spaced apart from the first portion.

The light-emitting element array may further includes:a first electrode pad that is electrically connected to the first wire and the second wire and includes a first portion and a second portion, the first portion and the second portion being located in opposite directions via the light-emitting element group in the first direction; anda second electrode pad that is electrically connected to the third wire and the fourth wire and includes a third portion and a fourth portion, the third portion and the fourth portion being located in opposite directions via the light-emitting element group in the second direction,the first wire being connected to the first portion and spaced apart from the second portion,the second wire being connected to the second portion and spaced apart from the first portion,the third wire being connected to the third portion and spaced apart from the fourth portion,the fourth wire being connected to the fourth portion and spaced apart from the third portion.

Each of the plurality of light-emitting elements may be a vertical cavity surface emitting laser element.

MODE(S) FOR CARRYING OUT THE INVENTION

A light-emitting element array according to an embodiment of the present technology will be described.

FIG.1is a plan view of a light-emitting element array100according to this embodiment, andFIG.2andFIG.3are each an enlarged view ofFIG.1. As shown in these figures, the light-emitting element array100includes first light-emitting elements111, second light-emitting elements112, a first electrode pad121, a second electrode pad122, first wires131, second wires132, third wires133, and fourth wires134. The first light-emitting elements111and the second light-emitting elements112constitute a light-emitting element group110.

FIG.4is a plan view of the light-emitting element group110. As shown in the figure, the light-emitting element group110includes a plurality of first light-emitting elements111and a plurality of second light-emitting elements112arranged in a planar shape.FIG.5andFIG.6are each a cross-sectional view of the light-emitting element group110.FIG.5is a cross-sectional view taken along the line A inFIG.4, andFIG.6is a cross-sectional view taken along the line B inFIG.4. Hereinafter, as shown inFIGS.5and6, a surface on which the first light-emitting elements111and the second light-emitting elements112are arranged will be referred to as a light-emitting element surface115, one direction parallel to the light-emitting element surface115will be referred to as an X direction, and a direction parallel to the light-emitting element surface115and orthogonal to the X direction will be referred to as a Y direction. That is, the light-emitting element surface115is parallel to the X-Y plane. Further, a direction perpendicular to the light-emitting element surface115will be referred to as a Z direction. Note that the number of first light-emitting elements111and the number of second light-emitting elements112are not particularly limited, and may each be, for example, several tens to several thousands.

The first light-emitting element111and the second light-emitting element112can be light-emitting elements having the same configuration.FIG.7is a plan view of a light-emitting element150capable of forming the first light-emitting element111and the second light-emitting element112, andFIG.8is a cross-sectional view of the light-emitting element150. The light-emitting element150is a vertical cavity surface emitting laser (VCSEL) element. As shown inFIG.8, the light-emitting element150is surrounded by an annular recessed portion152provided in a substrate151and has a mesa structure in which a mesa (plateau shape)153is formed.

As shown inFIG.8, the light-emitting element150includes an n-type DBR layer154, an active layer155, a current confinement layer156, a p-type DBR layer157, a p-electrode158, and an n-electrode159. The n-type DBR layer154, the active layer155, the current confinement layer156, and the p-type DBR layer157are stacked on the substrate151in this order.

The n-type DBR layer154is formed of an n-type semiconductor material, functions as a DBR (Distributed Bragg Reflector), and reflects light having specific wavelength (hereinafter, a wavelength A). The n-type DBR layer154constitutes an optical resonator for laser oscillation together with the p-type DBR layer157. The active layer155is provided between the n-type DBR layer154and the p-type DBR layer157, and emits and amplifies spontaneous emitted light. The active layer155can include a plurality of layers obtained by alternately stacking a quantum well layer and a barrier layer.

The current confinement layer156is provided in the vicinity of the active layer155and imparts a confinement action to a current. The current confinement layer156includes a non-oxidized region156aand an oxidized region156b. The non-oxidized region156ais provided in the center of the current confinement layer156and the oxidized region156bis provided around the non-oxidized region156a. The oxidized region156bcan be formed by performing oxidation treatment from the outer periphery side of a mesa153via the recessed portion152.

The p-type DBR layer157is formed of a p-type semiconductor material, functions as a DBR, and reflects light having the wavelength A. The p-type DBR layer157constitutes an optical resonator for laser oscillation together with the n-type DBR layer154. The p-electrode158is provided on the surface of the mesa153and is electrically connected to the p-type DBR layer157. As shown inFIG.7, the p-electrode158has an annular shape. The n-electrode159is provided on the surface of the substrate151on the side opposite to the light-emitting element150and is electrically connected to the n-type DBR layer154via the substrate151.

The light-emitting element150has the configuration as described above. In the light-emitting element150, when a voltage is applied between the p-electrode158and the n-electrode159, a current flows between the p-electrode158and the n-electrode159. The current is subjected to a current confinement action by the current confinement layer156and is injected into the active layer155in the vicinity of the non-oxidized region156a. This injected current causes spontaneously emitted light in the active layer155, and the spontaneously emitted light is reflected by the n-type DBR layer154and the p-type DBR layer157. Of the spontaneously emitted light, a component of the oscillation wavelength λ forms a standing wave between the n-type DBR layer154and the p-type DBR layer157and is amplified by the active layer155. 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 layer157and is emitted. InFIG.7andFIG.8, a surface from which a laser beam is emitted is shown as a light-emitting surface S. The p-electrode158is provided around the light-emitting surface S.

Note that the configuration of the light-emitting element150is not limited to the one shown here. For example, the n-type and the p-type in the light-emitting element150may be reversed. Further, although the above configuration shows the configuration of a surface emission type VCSEL element, the light-emitting element150may be a backside emission type VCSEL. Further, the light-emitting element150is 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 inFIG.4, the light-emitting element array100can be a light-emitting element array in which the first light-emitting elements111and the second light-emitting elements112having the configuration of the light-emitting element150are arranged. In the first light-emitting element111and the second light-emitting element112, the size of the mesa153may differ as shown inFIG.4or the size of the mesa153may be the same.

The first light-emitting element111and the second light-emitting element112have the configurations as described above. Here, the first light-emitting element111and the second light-emitting element112are configured to be capable of emitting light independently of each other. Specifically, as shown inFIG.8, the n-electrode159is uniformly formed on the back surface of the substrate151and is a common electrode between the first light-emitting element111and the second light-emitting element112.

Meanwhile, the p-electrode158is provided on the mesa153and is an independent electrode for each of the first light-emitting elements111and the second light-emitting elements112. Therefore, by applying a voltage between the p-electrode158provided in the first light-emitting element111and the n-electrode159, the first light-emitting element111can be caused to emit light. By applying a voltage between the p-electrode158provided in the second light-emitting element112and the n-electrode159, the second light-emitting element112can be caused to emit light. Note that in the figures other thanFIG.8, illustration of the layer structure of the light-emitting element150is omitted.

The first light-emitting elements111and the second light-emitting elements112are arranged on the light-emitting element surface115.FIG.9is a schematic diagram showing arrangement of the first light-emitting elements111and the second light-emitting elements112, and is a diagram of the light-emitting element surface115as viewed from a direction (Z direction) perpendicular to the light-emitting element surface115(X-Y plane). As shown in the figure, the first light-emitting elements111are arranged in one direction (X direction) parallel to the light-emitting element surface115(X-Y plane) to form respective first light-emitting element columns L1. Hereinafter, this arrangement direction (X direction) of the first light-emitting elements111will be referred to as a first arrangement direction. Further, the second light-emitting elements112are arranged along a direction (Y direction) parallel to the light-emitting element surface115(X-Y plane) and orthogonal to the first arrangement direction (X direction) to form respective second light-emitting element columns L2. Hereinafter, this arrangement direction (Y direction) of the second light-emitting elements112will be referred to as a second arrangement direction.

The first electrode pad121is an electrode pad for the first light-emitting elements111and is formed of a conductive material such as Au.FIG.10is a plan view showing the first electrode pad121and the light-emitting element group110and is a diagram showing a partial configuration ofFIG.1. As shown in the figure, the first electrode pad121includes a first portion121a, a second portion121b, and a connection portion121c. The first portion121aand the second portion121aare located in opposite directions via the light-emitting element group110in a direction (X direction) parallel to the first arrangement direction, i.e., are disposed so as to sandwich the light-emitting element group110in the same direction (X direction). The connection portion121cis provided between the first portion121aand the second portion121band electrically connects the first portion121aand the second portion121bto each other.

The second electrode pad122is an electrode pad for the second light-emitting elements112and is formed of a conductive material such as Au.FIG.11is a plan view showing the second electrode pad122and the light-emitting element group110and is a diagram showing a partial configuration ofFIG.1. As shown in the figure, the second electrode pad122includes a third portion122a, a fourth portion122b, and a connection portion122c. The third portion122aand the fourth portion122bare located in opposite directions via the light-emitting element group110in a direction (Y direction) parallel to the second arrangement direction, i.e., are disposed so as to sandwich the light-emitting element group110in the same direction (Y direction). The connection portion122cis provided between the third portion122aand the fourth portion122band electrically connects the third portion122aand the fourth portion122bto each other.

The first wire131and the second wire132are wires for the first light-emitting elements111, are electrically connected to each of the first light-emitting elements111in each of the first light-emitting element columns L1, and are insulated from each of the second light-emitting elements112. The first wire131and the second wire132are formed of a conductive material such as Au.FIG.12is a plan view showing a configuration relating to the first light-emitting elements111inFIG.2, andFIG.13is a plan view in which illustration of the first light-emitting elements111inFIG.12is omitted. As shown inFIG.13, the first wire131and the second wire132extend along a first extending direction (X direction) parallel to the first arrangement direction and are spaced apart from each other. The first wire131is connected to the first portion121aof the first electrode pad121and spaced apart from the second portion121b. The second wires132is connected to the second portion121bof the first electrode pad121and spaced apart from the first portion121a.

FIG.14is an enlarged view ofFIG.12. As shown in the figure, the first wire131and the second wire132are superimposed on the individual first light-emitting elements111as viewed from a direction (Z direction) perpendicular to the light-emitting element surface115. Hereinafter, a region of the first wire131superimposed on the first light-emitting element111as viewed from the same direction (Z direction) will be referred to as a first superimposition region131a. A first current injection port141adescribed below is provided in the first superimposition region131a, and the first wire131is electrically connected to the p-electrode158(seeFIG.7) of each first light-emitting element111via the first current injection port141a.

Further, a region of the second wire132superimposed on the first light-emitting element111as viewed from a direction (Z direction) perpendicular to the light-emitting element surface115will be referred to as a second superimposition region132a. A second current injection port141bdescribed below is provided in the second superimposition region132a, and the second wire132is electrically connected to the p-electrode158(seeFIG.7) of each first light-emitting element111via the second current injection port141b. Note that as shown inFIG.13, the first wire131and the second wire132suitably have a shape in which a notch is provided on the light-emitting surface S. By adopting this shape, it is possible to increase the wire width of the first wire131and the second wire132without blocking the light-emitting surface S.

The third wire133and the fourth wire134are wires for the second light-emitting elements112, are electrically connected to each of the second light-emitting elements112in each of the second light-emitting element columns L2, and are insulated from each of the first light-emitting elements111. The third wire133and the fourth wire134are formed of a conductive material such as Au.FIG.15is a plan view showing a configuration relating to the second light-emitting elements112inFIG.2, andFIG.16is a plan view in which illustration of the second light-emitting elements112is omitted inFIG.15. As shown inFIG.16, the third wire133and the fourth wire134extend along a second extending direction (Y direction) parallel to the second arrangement direction and are spaced apart from each other. The second extending direction (Y direction) is a direction orthogonal to the first extending direction (X direction). The third wire133is connected to the third portion122aof the second electrode pad122and spaced apart from the fourth portion122b. The fourth wire134is connected to the fourth portion122bof the second electrode pad122and spaced apart from the third portion122a.

FIG.17is an enlarged view ofFIG.15. As shown in the figure, the third wire133and the fourth wire134are superimposed on the individual second light-emitting elements112as viewed from a direction (Z direction) perpendicular to the light-emitting element surface115. Hereinafter, a region of the third wire133superimposed on the second light-emitting element112as viewed from the same direction (Z direction) will be referred to as a third superimposition region133a. A third current injection port142adescribed below is provided in the third superimposition region133a, and the third wire133is electrically connected to the p-electrode158(seeFIG.7) of each second light-emitting element112via the third current injection port142a.

Further, a region of the fourth wire134superimposed on the second light-emitting element112as viewed from a direction (Z direction) perpendicular to the light-emitting element surface115will be referred to as a fourth superimposition region134a. A fourth current injection port142bdescribed below is provided in the fourth superimposition region134a, and the fourth wire134is electrically connected to the p-electrode158(seeFIG.7) of each second light-emitting element112via the fourth current injection port142b. Note that as shown inFIG.16, the third wire133and the fourth wire134suitably have a shape in which a notch is provided on the light-emitting surface S. By adopting this shape, it is possible to increase the wire width of the third wire133and the fourth wire134without blocking the light-emitting surface S.

The light-emitting element array100has the wiring structure as described above. Note that the light-emitting element array100does not need to include all the above configurations, and only needs to include at least the first light-emitting elements111, the first wires131, and the second wires132.

The stacked structure of the light-emitting element array100will be described.FIG.18is a schematic diagram showing a cross section of the light-emitting element array100.FIG.19is a cross-sectional view of the light-emitting element array100taken along the line C inFIG.18,FIG.20is a cross-sectional view of the light-emitting element array100taken along the line D inFIG.18, andFIG.21is a cross-sectional view of the light-emitting element array100taken along the line E inFIG.18. As shown in these figures, the light-emitting element array100may further include a first insulation layer141and a second insulation layer142.

The first insulation layer141is formed of an insulating material, and is disposed on the light-emitting element surface115as shown inFIG.19toFIG.21. As shown inFIG.19, the first wire131and the second wire132are disposed on the first insulation layer141. As shown inFIG.20, the first electrode pad121is disposed on the first insulation layer141. The second insulation layer142is formed of an insulating material, and is disposed on the first insulation layer141, the first wire131, and the second wire132as shown inFIG.19toFIG.21. As shown inFIG.20, the second insulation layer142is not disposed on the first electrode pad121. As shown inFIG.19andFIG.21, the third wire133and the fourth wire134are disposed on the second insulation layer142.

The first wire131and the second wire132are electrically connected to the first light-emitting elements111and are insulated from the second light-emitting elements112as described above.FIG.22is a cross-sectional view of the light-emitting element array100taken along the line F inFIG.18, andFIG.23is a cross-sectional view showing a partial configuration ofFIG.22. As shown inFIG.23, the first current injection port141aand the second current injection port141b, which are through holes, are provided in the first insulation layer141.FIG.24is a schematic diagram showing a positional relationship between the first current injection port141a, the second current injection port141b, and the first light-emitting elements111.

The first current injection port141ais provided in the first superimposition region131a(seeFIG.14) as described above, and is located on the p-electrode158of the first light-emitting element111as shown inFIG.23andFIG.24. The second current injection port141bis provided in the second superimposition region132a(seeFIG.14) as described above, and is located on the p-electrode158of the first light-emitting element111as shown inFIG.23andFIG.24. As shown inFIG.22, the first wire131is in contact with the p-electrode158via the first current injection port141aand electrically connected to the first light-emitting element111. As shown inFIG.22, the second wire132is in contact with the p-electrode158via the second current injection port141band electrically connected to the first light-emitting element111. Although one first light-emitting element111has been illustrated here, the first wire131and the second wire132are electrically connected to the other first light-emitting elements111, similarly.

The third wire133and the fourth wire134are electrically connected to the second light-emitting elements112and insulated from the first light-emitting elements111as described above.FIG.25is a cross-sectional view of the light-emitting element array100taken along the line G inFIG.18, andFIG.26is a cross-sectional view showing a partial configuration ofFIG.25. As shown inFIG.26, the third current injection port142aand the fourth current injection port142b, which are through holes, are provided in the first insulation layer141and the second insulation layer142.FIG.27is a schematic diagram showing a positional relationship of the third current injection port142a, the fourth current injection port142b, and the second light-emitting element112.

The third current injection port142ais provided in the third superimposition region133a(seeFIG.17) as described above, and is located on the p-electrode158of the second light-emitting element112as shown inFIG.26andFIG.27. The fourth current injection port142bis provided in the fourth superimposition region134a(seeFIG.17) as described above, and is located on the p-electrode158of the second light-emitting element112as shown inFIG.26andFIG.27. As shown inFIG.25, the third wire133is in contact with the p-electrode158via the third current injection port142aand is electrically connected to the second light-emitting element112. As shown inFIG.25, the fourth wire134is in contact with the p-electrode158via the fourth current injection port142band is electrically connected to the second light-emitting element112. Although one second light-emitting element112has been illustrated here, the third wire133and the fourth wire134are electrically connected to the other second light-emitting elements112, similarly.

The light-emitting element array100has the stacked structure as described above. By making the light-emitting element array100have such a stacked structure, it is possible to insulate the first wire131and the second wire132from the third wire133and the fourth wire134between layers, and intersect the first wire131and the second wire132with the third wire133and the fourth wire134(seeFIG.2).

Although the method of forming the stacked structure of the light-emitting element array100is not particularly limited, it can be formed as follows. That is, after forming the light-emitting element group110, the first insulation layer141is formed on the light-emitting element surface115, and the first current injection port141aand the second current injection port141b(seeFIG.23) are formed at the above positions. The first current injection port141aand the second current injection port141bcan be formed by removing the first insulation layer141by RIE (Reactive Ion Etching) or the like. Next, the first electrode pad121, the first wires131, and the second wires132are formed on the first insulation layer141, and these wires are caused to be electrically connected to the first light-emitting elements111via the first current injection port141aand the second current injection port141b(seeFIG.22).

Next, the second insulation layer142is formed on the first insulation layer141, the first electrode pad121, the first wires131, and the second wires132, and the third current injection port142aand the fourth current injection port142b(seeFIG.26) are formed at the above positions. The third current injection port142aand the fourth current injection port142bcan be formed by removing the second insulation layer142and the first insulation layer141by RIE or the like. At the same time, the first insulation layer141on the first electrode pad121is removed by RIE or the like to expose the first electrode pad121(seeFIG.20). Next, the second electrode pad122, the third wires133, and the fourth wires134are formed on the second insulation layer142, and these wires are caused to be electrically connected to the second light-emitting elements111via the third current injection port142aand the fourth current injection port142b(seeFIG.25).

The light-emitting element array100can be mounted by wire bonding or the like. In the wire bonding, a drive signal wire of the first light-emitting element111can be bonded to the first portion121aand the connection portion121c(seeFIG.10), and a drive signal wire of the second light-emitting element112can be bonded to the third portion122aand the connection portion122c(seeFIG.11). Further, a drive signal wire of the first light-emitting element111may be bonded to the first portion121aand the second portion121b(seeFIG.10), and a drive signal wire of the second light-emitting element112may be bonded to the third portion122aand the fourth portion122b(seeFIG.11). The light-emitting element array100can also be mounted by other mounting methods.

An operation of the light-emitting element array100will be described.FIG.28is a schematic diagram showing a drive current of the first light-emitting elements111. When a voltage is applied to the first electrode pad121, a current flows through the first wire131and the second wire132. As described above, the first wire131is connected to the first portion121aof the first electrode pad121and spaced apart from the second portion121b. For this reason, the current flowing through the first wire131flows into the first wire131from the first portion121aand flows through the first wire131toward the first light-emitting element111as shown by arrows inFIG.28. Hereinafter, the orientation of the current flowing through the first wire131will be referred to as a first orientation D1. The first orientation D1is parallel to the first extending direction (X direction) that is the extending direction of the first wire131and is an orientation from the first portion121atoward the second portion121b.

Further, the second wire132is connected to the second portion121bof the first electrode pad121and spaced apart from the first portion121a. For this reason, the current flowing through the second wire132flows into the second wire132from the second portion121bas shown by arrows inFIG.28and flows through the second wire132toward each first light-emitting element111. Hereinafter, the orientation of the current flowing through the second wire132will be referred to as a second orientation D2. The second orientation D2is parallel to the first extending direction (X direction) that is the extending direction of the second wire133and is an orientation from the second portion121btoward the first portion121a. Therefore, the first orientation D1and the second orientation D2are orientations opposite to each other.

FIG.29is a schematic diagram showing a drive current of the second light-emitting elements112. When a voltage is applied to the second electrode pad121, a current flows through the third wire133and the fourth wire134. As described above, the third wire133is connected to the third portion122aof the second electrode pad122and spaced apart from the fourth portion122b. For this reason, the current flowing through the third wire133flows into the third wire133from the third portion122aas shown by arrows inFIG.29and flows through the third wire133toward each second light-emitting element112. Hereinafter, the orientation of the current flowing through the third wire133will be referred to as a third orientation D3. The third orientation D3is parallel to the second extending direction (Y direction) that is the extending direction of the third wire133and is an orientation from the third portion122atoward the fourth portion122b.

Further, the fourth wire134is connected to the fourth portion122bof the second electrode pad122and spaced apart from the third portion122a. For this reason, the current flowing through the fourth wire134flows into the fourth wire134from the fourth portion122bas shown by arrows inFIG.29and flows through the fourth wire134toward each second light-emitting element112. Hereinafter, the orientation of the current flowing through the fourth wire134will be referred to as a fourth orientation D4. The fourth orientation D4is parallel to the second extending direction (Y direction) that is the extending direction of the fourth wire134and is an orientation from the fourth portion122btoward the third portion122a. Therefore, the third orientation D3and the fourth orientation D4are orientations opposite to each other.

The first light-emitting element111and the second light-emitting element can be caused to emit light separately. When a voltage is applied to the first electrode pad121, a current in the first orientation D1flows through the first wire131, and at the same time, a current in the second orientation D2flows through the second wire132. As a result, each first light-emitting element111electrically connected to the first wire131and the second wire132emits light. Further, when a voltage is applied to the second electrode pad122, a current in the third orientation D3flows through the third wire133, and at the same time, a current in the fourth orientation D4flows through the fourth wire134. As a result, each second light-emitting element112electrically connected to the third wire133and the fourth wire134emits light.

The effects of the light-emitting element array100will be described in comparison with Comparative Example.FIG.30is a schematic diagram of a light-emitting element array300according to Comparative Example. As shown in the figure, the light-emitting element array300includes first light-emitting elements311, second light-emitting elements312, a first electrode pad321, a second electrode pad322, first wires331, and second wires332. The first light-emitting elements311and the second light-emitting elements312constitute a light-emitting element group310.

The first electrode pad321and the second electrode pad322are disposed on the opposite sides via the light-emitting element group310. The first wire331extends from the first electrode pad321and is electrically connected to each first light-emitting element311. The second wire332extends from the second electrode pad322and is electrically connected to each second light-emitting element312.FIG.31is a schematic diagram showing orientations of currents in the light-emitting element array300. As shown in the figure, a current in a first orientation E1flows through the first wire331from the first electrode pad321and is supplied to each first light-emitting element311. Further, a current in a second orientation E2flows through the second wire332from the second electrode pad322and is supplied to each second light-emitting element312. The first orientation E1and the second orientation E2are orientations opposite to each other.

Here, since only the current in the first orientation E1is supplied to the first light-emitting element311, the arrival of the current to the first light-emitting element311far from the first electrode pad321is delayed. Similarly, since only the current in the second orientation E2is supplied to the second light-emitting elements312, the arrival of the current to the second light-emitting element312far from the second electrode pad322is delayed. For this reason, in the configuration of the light-emitting element array300, a decrease in the response speed of the first light-emitting element311and the second light-emitting element312becomes a problem.

Meanwhile, in the light-emitting element array100according to this embodiment, currents in both the first orientation D1and the second orientation D2are supplied to the first light-emitting elements111as shown inFIG.28. For this reason, the current in the second orientation D2is supplied from the second portion121bto the first light-emitting element111far from the first portion121a, and the current in the first orientation D1is supplied from the first portion121ato the first light-emitting element111far from the second portion121b. As a result, the delay in the arrival of the current to the first light-emitting element111far from the first electrode pad121is suppressed, and the response speed is improved. Further, the first wire131and the second wire132are close to each other, and the first orientation D1and the second orientation D2are orientations opposite to each other. For this reason, the current in the first orientation D1and the current in the second orientation D2cancel each other's magnetic fields, and the effect of reducing the inductance is achieved. This reduction in inductance also improves the response speed.

Also regarding the second light-emitting elements112, as shown inFIG.29, currents in both the third orientation D3and the fourth orientation D4are supplied to the second light-emitting elements112. For this reason, the current in the fourth orientation D4is supplied from the fourth portion122bto the second light-emitting element112far from the third portion122a, and the current in the third orientation D3is supplied from the third portion122ato the second light-emitting element112far from the fourth portion122b. As a result, the delay in the arrival of the current to the second light-emitting element112far from the second electrode pad122is suppressed, and the response speed is improved. Further, the third wire133and the fourth wire134are close to each other, and the third orientation D3and the fourth orientation D4are orientations opposite to each other. For this reason, the current in the third orientation D3and the current in the fourth orientation D4cancel each other's magnetic fields, and the effect of reducing the inductance is achieved. This reduction in inductance also improves the response speed. In this way, in the light-emitting element array100, it is possible to improve the response speed of the first light-emitting elements111and the second light-emitting elements112.

Further, in the light-emitting element array100, the first wires131and the second wires132are disposed in a layer different from that of the third wires133and the fourth wires134(seeFIG.19). For this reason, it is possible to increase the width of each wire as compared with the case where the wires are disposed in the same layer. As a result, it is possible to reduce the drive voltage of each of the first light-emitting elements111and the second light-emitting elements112.

Modified Example

Although the light-emitting element array100includes the first light-emitting elements111and the second light-emitting elements112in the above description, it may include only the first light-emitting elements111. In this case, the light-emitting element array100may include only the first light-emitting elements111, the first electrode pad121, the first wires131, and the second wires132.

Further, although the first extending direction that is the extending direction of the first wires131and the second wires132and the second extending direction that is the extending direction of the third wires133and the fourth wires134are orthogonal to each other (seeFIG.3) in the above description, the present technology is not limited thereto. For example, the first extending direction and the second extending direction may intersect at an angle of 80°, 45°, or the like. Further, although the first light-emitting element111and the second light-emitting element112have a mesa structure (seeFIG.8) in which the mesa153is formed in the above description, the present technology is not limited thereto. The first light-emitting element111and the second light-emitting element112may have a light-emitting structure other than the mesa structure.

The light-emitting element array100is capable of causing the first light-emitting element111and the second light-emitting element112to emit light independently as described above and can be used for a ranging light source device capable of emitting light for short distances and light for long distances.

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 exhibited simultaneously. It means that at least one of the effects described above can be achieved in accordance with the conditions or the like, and there is a possibility that an effect that is not described in the present disclosure is exerted. Further, at least two feature portions of the feature portions 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 forms a light-emitting element surface on which a plurality of light-emitting elements is arranged in a planar shape and includes first light-emitting element columns, first light-emitting elements included in the plurality of light-emitting elements being arranged along a first direction parallel to the light-emitting element surface in each of the first light-emitting element columns;a first wire that extends along the first direction and is electrically connected to each of the first light-emitting elements in each of the first light-emitting element columns, a current flowing through the first wire in a first orientation parallel to the first direction; anda second wire that extends along the first direction and is electrically connected to each of the first light-emitting elements in each of the first light-emitting element columns, a current flowing through the second wire in a second orientation parallel to the first direction and opposite to the first orientation.

(2) The light-emitting element array according to (1) above, in whichthe light-emitting element group further includes second light-emitting element columns, second light-emitting elements included in the plurality of light-emitting elements being arranged along a second direction parallel to the light-emitting element surface in each of the second light-emitting element columns, the light-emitting element array further including:a third wire that extends along the second direction and is electrically connected to each of the second light-emitting elements in each of the second light-emitting element columns, a current flowing through the third wire in a third orientation parallel to the second direction; anda fourth wire that extends along the second direction and is electrically connected to each of the second light-emitting elements in each of the second light-emitting element columns, a current flowing through the fourth wire in a fourth orientation parallel to the second direction and opposite to the third orientation.

(3) The light-emitting element array according to (2) above, in whichthe first direction and the second direction are orthogonal to each other.

(4) The light-emitting element array according to (2) or (3) above, further including:a first insulation layer formed of an insulating material; anda second insulation layer formed of an insulating material,the first insulation layer being disposed on the light-emitting element surface,the first wire and the second wire being disposed on the first insulation layer,the second insulation layer being formed on the first insulation layer, the first wire, and the second wire,the third wire and the fourth wire being disposed on the second insulation layer.

(5) The light-emitting element array according to (4) above, in whichthe first wire is electrically connected to each of the first light-emitting elements via a first current injection port provided in the first insulation layer,the second wire is electrically connected to each of the first light-emitting elements via a second current injection port provided in the first insulation layer,the third wire is electrically connected to each of the second light-emitting elements via a third current injection port provided in the first insulation layer and the second insulation layer, andthe fourth wire is electrically connected to each of the second light-emitting elements via a fourth current injection port provided in the first insulation layer and the second insulation layer.

(6) The light-emitting element array according to (5) above, in whichthe first wire has a first superimposition region that is superimposed on the first light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the first current injection port being provided within the first superimposition region as viewed from the direction,the second wire has a second superimposition region that is superimposed on the first light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the second current injection port being provided within the second superimposition region as viewed from the direction,the third wire has a third superimposition region that is superimposed on the second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the third current injection port being provided within the third superimposition region as viewed from the direction, andthe fourth wire has a fourth superimposition region that is superimposed on the second light-emitting elements as viewed from a direction perpendicular to the light-emitting element surface, the fourth current injection port being provided within the fourth superimposition region as viewed from the direction.

(7) The light-emitting element array according to any one of (1) to (6) above, further includinga first electrode pad that is electrically connected to the first wire and the second wire and includes a first portion and a second portion, the first portion and the second portion being located in opposite directions via the light-emitting element group in the first direction,the first wire being connected to the first portion and spaced apart from the second portion,the second wire being connected to the second portion and spaced apart from the first portion.

(8) The light-emitting element array according to any one of (2) to (6) above, further including:a first electrode pad that is electrically connected to the first wire and the second wire and includes a first portion and a second portion, the first portion and the second portion being located in opposite directions via the light-emitting element group in the first direction; anda second electrode pad that is electrically connected to the third wire and the fourth wire and includes a third portion and a fourth portion, the third portion and the fourth portion being located in opposite directions via the light-emitting element group in the second direction,the first wire being connected to the first portion and spaced apart from the second portion,the second wire being connected to the second portion and spaced apart from the first portion,the third wire being connected to the third portion and spaced apart from the fourth portion,the fourth wire being connected to the fourth portion and spaced apart from the third portion.

(9) The light-emitting element array according to any one of (1) to (8) above, in whicheach of the plurality of light-emitting elements is a vertical cavity surface emitting laser element.

REFERENCE SIGNS LIST