Light-emitting element and reflective encoder

Abstract

To provide a light emitting element capable of suppressing decline in detection accuracy when applied to a reflective-type encoder and a reflective-type encoder including such a light emitting element.SOLUTION: A light emitting element 3 includes: a substrate 10; a mesa portion 20 formed on the substrate 10 and including an active layer 21, a first semiconductor layer 22 and a second semiconductor layer 23; a metal layer 30 including a first metal part 31 disposed on a top surface 25 of the mesa portion 20 and connected to the second semiconductor layer 23 and a second metal part 32 formed integrally with the first metal part 31 and extending along a side surface 26 of the mesa portion 20; an insulating layer 40 formed on the side surface 26; and a resin layer 50 formed on the insulating layer 40. The first metal part 31 includes an opening region 35 where a light passage opening 35a is formed and a connection region 36 for external connection. The second metal part 32 is formed on the side surface 26 via the insulating layer 40 and the resin layer 50, and overlaps the active layer 21 when viewed in a direction perpendicular to a thickness direction of the substrate 10.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light-emitting element and a reflective encoder. [Background technology]

[0002] Patent Document 1 discloses a light-emitting element that can be used as a light source for a reflective encoder, which includes a substrate and a mesa portion formed on the substrate. In this light-emitting element, a light-emitting window is formed on the top surface of the mesa portion, and light is emitted from the light-emitting window along the thickness direction of the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-216598 Summary of the Invention [Problem to be solved by the invention]

[0004] When the light-emitting element described above is applied to a reflective encoder, the light leaking from the side of the mesa portion may be detected as noise by the light-receiving element of the reflective encoder, which may result in a decrease in detection accuracy.

[0005] An object of the present invention is to provide a light-emitting element that can suppress a decrease in detection accuracy when applied to a reflective encoder, and a reflective encoder including such a light-emitting element. [Means for solving the problem]

[0006] The light-emitting element of the present invention includes a substrate, an active layer that generates light, a first semiconductor layer arranged on the substrate side of the active layer, and a second semiconductor layer arranged on the opposite side of the substrate from the active layer, and is equipped with a mesa portion formed on the substrate, a metal layer arranged on the top surface of the mesa portion and having a first portion arranged on the top surface of the mesa portion and electrically connected to the second semiconductor layer, and a second portion formed integrally with the first portion and extending along the side surface of the mesa portion, an insulating layer formed on at least the side surface of the mesa portion, and a resin layer formed on the insulating layer, wherein the first portion includes a region where a light passage opening through which light passes is formed and a region for external connection, and the second portion is formed on the side surface of the mesa portion via the insulating layer and the resin layer, and overlaps at least the active layer when viewed from a direction perpendicular to the thickness direction of the substrate.

[0007] In this light-emitting device, the metal layer has a first portion disposed on the top surface of the mesa portion and electrically connected to the second semiconductor layer, as well as a second portion integrally formed with the first portion and extending along the side surface of the mesa portion. When viewed from a direction perpendicular to the thickness direction of the substrate, the second portion overlaps at least the active layer. This allows the second portion to block light leaking from the side surface of the mesa portion, thereby suppressing light leakage from the side surface of the mesa portion. Furthermore, while simply forming a metal layer on the side surface of the mesa portion can result in poor formation of the metal layer, in this light-emitting device, the second portion of the metal layer is formed on the side surface of the mesa portion via an insulating layer and a resin layer. This allows the second portion of the metal layer to be formed on the side surface of the mesa portion properly, thereby effectively suppressing light leakage from the side surface of the mesa portion. Therefore, when this light-emitting device is applied to a reflective encoder, it is possible to suppress a decrease in detection accuracy.

[0008] The second portion may extend to the end of the mesa portion on the substrate side when viewed from a direction perpendicular to the thickness direction of the substrate, which makes it possible to more effectively suppress light leakage from the side surface of the mesa portion.

[0009] The top surface of the mesa portion, when viewed in the thickness direction of the substrate, is formed in a rectangular shape having a pair of first sides extending in a first direction and a pair of second sides extending in a second direction perpendicular to the first direction. The side surfaces of the mesa portion have a pair of first surfaces connected to the top surface at the pair of first sides and a pair of second surfaces connected to the top surface at the pair of second sides. In the first portion, the light passage opening is formed closer to one of the pair of first surfaces than the center of the top surface when viewed in the thickness direction of the substrate. The second portion may be formed on at least one of the pair of first surfaces and the pair of second surfaces. In this case, since the light passage opening in the first portion of the metal layer is formed closer to one of the pair of first surfaces, a wide area for external connection can be secured. As a result, for example, it can be easier to connect external wiring to the area. On the other hand, in this case, light is more likely to leak from the one of the pair of first surfaces. In this regard, in this light-emitting element, the second portion is formed on at least one of the pair of first surfaces and the pair of second surfaces, so that even in such cases, leakage of light from the side surface of the mesa portion can be reliably suppressed.

[0010] The second portion may be formed around the entire periphery of the side surface of the mesa portion, in which case light leakage from the side surface of the mesa portion can be more effectively suppressed.

[0011] The resin layer may include a portion whose thickness decreases toward the substrate side. In this case, the surface of the resin layer opposite the mesa portion can be made smooth, allowing the second portion of the metal layer to be more effectively formed on the side surface of the mesa portion. Furthermore, light leaking into the resin layer from the side surface of the mesa portion is attenuated by being repeatedly reflected between the side surface of the mesa portion and the second metal portion of the metal layer. In the above-described configuration in which the resin layer includes a portion whose thickness decreases toward the substrate side, the number of reflections of light leaking into the resin layer increases, thereby enabling efficient attenuation of the leaked light.

[0012] The side surface of the mesa may be formed as a curved surface that protrudes inward of the mesa, which makes it difficult to form the second portion of the metal layer on the side surface of the mesa. However, with this light-emitting device, for the reasons described above, the second portion of the metal layer can be successfully formed on the side surface of the mesa even in such a case.

[0013] The surface of the resin layer opposite the mesa portion may include a region formed in a curved shape that is convex toward the side opposite the mesa portion, which allows the second portion of the metal layer to be more effectively formed on the side surface of the mesa portion.

[0014] The metal layer may cover the entire surface of the resin layer opposite the mesa portion, which can more effectively suppress light leakage from the side surface of the mesa portion and can also effectively suppress deterioration of the resin layer due to contact with air.

[0015] The resin layer may have a portion formed on the top surface of the mesa portion, but may not be formed between the region for external connection in the first portion and the top surface of the mesa portion. In this case, the resin layer is formed not only on the side surfaces of the mesa portion but also on the top surface of the mesa portion, allowing the resin layer to be formed well. Furthermore, since the resin layer is not formed between the region for external connection in the first portion and the top surface of the mesa portion, it is possible to prevent a situation in which the presence of the resin layer prevents external wiring from being properly connected to the region for external connection.

[0016] The resin layer may have a portion formed on the top surface of the mesa portion, and the portion of the resin layer formed on the top surface of the mesa portion may extend along the outer edge of the top surface of the mesa portion when viewed from the thickness direction of the substrate. In this case, the resin layer is formed not only on the side surfaces of the mesa portion but also on the top surface of the mesa portion, allowing for a satisfactory formation of the resin layer. Furthermore, since the portion of the resin layer formed on the top surface of the mesa portion extends along the outer edge of the top surface of the mesa portion when viewed from the thickness direction of the substrate, it is possible to prevent a situation in which the presence of the resin layer prevents a satisfactory connection of external wiring to the external connection region.

[0017] The insulating layer may have a portion formed on the top surface of the mesa portion to cover the portion exposed from the light passage opening, in which case the portion of the top surface of the mesa portion exposed from the light passage opening can be protected by the insulating layer.

[0018] The first portion may be formed over the entire top surface of the mesa portion except for a portion corresponding to the light passage opening. In this case, a wide area for external connection can be secured in the first portion, which can facilitate, for example, connecting external wiring to the area. Furthermore, since the first portion has a simpler shape than when the first portion is formed as a complex wiring pattern, for example, unintended short circuits between the first portions can be suppressed.

[0019] The reflective encoder of the present invention includes the light-emitting element, a rotating plate having a reflective pattern that reflects light emitted from the light-emitting element, and at least one light-receiving unit that is arranged on the same side of the rotating plate as the light-emitting element and detects light reflected by the reflective pattern, and the second portion is formed at least in an area on the side surface of the mesa that faces the at least one light-receiving unit when viewed from the thickness direction of the substrate. With this reflective encoder, leakage light that enters the at least one light-receiving unit from the side surface of the mesa can be blocked by the second portion of the metal layer, thereby preventing a decrease in detection accuracy.

[0020] The at least one light receiving portion may include two light receiving portions disposed on both sides of the light emitting element in a direction perpendicular to the thickness direction of the substrate, and the second portion may be formed on at least two regions on the side surface of the mesa portion that face the two light receiving portions when viewed from the thickness direction of the substrate. In this case, leakage light that enters the two light receiving portions disposed on both sides of the light emitting element from the side surface of the mesa portion can be blocked by the second portion of the metal layer. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a light-emitting element that can suppress a decrease in detection accuracy when applied to a reflective encoder, and a reflective encoder equipped with such a light-emitting element. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a front view of a reflective encoder according to an embodiment. [Figure 2] FIG. 2 is a plan view of the light-emitting element shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5] FIG. 5 is an enlarged view of the portion shown in FIG. 4. [Figure 6] 1 is a photograph showing a part of a cross section of a light-emitting element. [Figure 7] 1 is a photograph showing a part of a cross section of a light-emitting element. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted. [Reflective Encoder]

[0024] 1, the reflective encoder 1 includes a rotating plate (code wheel) 2, a light-emitting element 3, and a light-receiving element 4. The reflective encoder 1 is, for example, an absolute rotary encoder, and is a device that detects the absolute angle of a rotating object to be measured by using reflected light from the object.

[0025] The rotating plate 2 has a main body 201 and a reflective pattern 202. The main body 201 is fixed to a rotating shaft (not shown) and rotates together with the rotating shaft. The main body 201 is formed, for example, in the shape of a disk. The reflective pattern 202 is formed on a main surface 201a of the main body 201. The reflective pattern 202 is a light-reflecting film made of a metal such as Cr, and reflects light L emitted from the light-emitting element 3. The reflective pattern 202 is arranged according to a predetermined pattern such as a gray code.

[0026] The light-emitting element 3 is a semiconductor element that outputs light, such as an LED (Light Emitting Diode). The light-emitting element 3 is fixed on the light-receiving element 4 so as to face the main surface 201a of the main body 201, and emits light L toward the rotating plate 2. The light L emitted from the light-emitting element 3 is reflected by the reflection pattern 202 and detected by a plurality of light-receiving portions 402 that the light-receiving element 4 has.

[0027] The light receiving element 4 is arranged on the same side of the rotating plate 2 as the light emitting element 3. The light receiving element 4 has a base 401 and a plurality of light receiving portions 402 formed on the base 401. The base 401 is formed, for example, in the shape of a rectangular plate, and has a main surface 401a facing the main surface 201a of the main body 201. The light emitting element 3 described above is fixed on the main surface 401a. Each light receiving portion 402 is, for example, a photodiode, and detects light L reflected by the reflection pattern 202. In this example, the plurality of light receiving portions 402 includes two light receiving portions 402A and 402B. The two light receiving portions 402A and 402B are arranged on both sides of the light emitting element 3 in the Y direction, which will be described later. [Light-emitting element]

[0028] Next, the configuration of the light-emitting device 3 will be further described. As shown in FIGS. 2 to 5, the light-emitting device 3 includes a substrate 10, a mesa portion 20, a metal layer 30, an insulating layer 40, a resin layer 50, and an electrode 60. In FIGS. 3 to 5, the configuration of the light-emitting device 3 is shown in simplified form. FIG. 4 shows a more detailed configuration of the light-emitting device compared to FIG. 3, and the configuration of an actual light-emitting device in a YZ cross-sectional view may have similar features to the configuration shown in FIG. 4 (the configuration in an XZ cross-sectional view). The substrate 10 is a semiconductor substrate, and is formed, for example, from GaAs in a substantially rectangular plate shape. Hereinafter, the thickness direction of the substrate 10 will be referred to as the Z direction, the direction perpendicular to the Z direction as the X direction, and the direction perpendicular to the Z and X directions as the Y direction.

[0029] The substrate 10 has a base 11 and a protruding portion 12 protruding from the base 11. In this example, the base 11 is formed in the shape of a rectangular plate (a rectangular parallelepiped). The protruding portion 12 protrudes from the surface of the base 11. The protruding portion 12 is formed, for example, in a substantially trapezoid shape in a cross section along the Z direction. An electrode 60 is formed on the surface of the base 11 opposite to the mesa portion 20. The electrode 60 is formed in a layer shape using a metal material such as AuGe, Ni, or Au.

[0030] The mesa portion 20 is formed on the protruding portion 12 of the substrate 10. The mesa portion 20 is formed, for example, in a substantially trapezoidal shape in a cross section along the Z direction. The mesa portion 20 includes an active layer 21, a first semiconductor layer 22, and a second semiconductor layer 23. The protruding portion 12 and the mesa portion 20 are formed, for example, by stacking the active layer 21, the first semiconductor layer 22, and the second semiconductor layer 23 on the substrate 10, and then removing parts of the substrate 10, the active layer 21, the first semiconductor layer 22, and the second semiconductor layer 23 by etching. The active layer 21 has, for example, a multiple quantum well structure, and generates light of a predetermined wavelength when a current is supplied thereto.

[0031] The first semiconductor layer 22 is disposed on the substrate 10 side with respect to the active layer 21. The first semiconductor layer 22 is configured by laminating a DBR (Distributed Bragg Reflector) layer 121 and a cladding layer 122 in this order on the protruding portion 12 of the substrate 10. The DBR layer 121 reflects light from the active layer 21 toward the active layer 21 side (upper side in FIG. 5). The cladding layer 122 has, for example, n-type conductivity.

[0032] The second semiconductor layer 23 is disposed on the opposite side of the substrate 10 with respect to the active layer 21. That is, in this example, the first semiconductor layer 22, the active layer 21, and the second semiconductor layer 23 are stacked in this order on the protruding portion 12 of the substrate 10. The second semiconductor layer 23 is configured by stacking a cladding layer 123, a blocking layer 124, a diffusion layer 125, and a contact layer 126 on the active layer 21 in this order. The cladding layer 123 has, for example, a p-type conductivity. The diffusion layer 125 is formed, for example, by forming layers corresponding to the blocking layer 124 and the diffusion layer 125 on the cladding layer 123, and then diffusing an impurity such as Zn into the portion of the layer corresponding to the diffusion layer 125. This makes it easier for current to flow through the diffusion layer 125 than through the blocking layer 124.

[0033] The diffusion layer 125 has a portion 125A formed to penetrate into the block layer 124. As the portion 125A is formed to penetrate into the block layer 124, a recess 25A is formed in a region corresponding to the portion 125A on the top surface 25 of the mesa portion 20, which will be described later. The portion 125A is formed in a circular shape when viewed from the Z direction, and is surrounded by the block layer 124. Because it is more difficult for a current to flow in the block layer 124 than in the diffusion layer 125, the current supplied to the diffusion layer 125 is confined to the portion 125A by the block layer 124. In this way, the block layer 124 and the diffusion layer 125 form a current confinement structure that confines the current flow to the portion 125A.

[0034] The mesa portion 20 has a top surface 25 and side surfaces 26. The top surface 25 is the surface of the mesa portion 20 opposite to the substrate 10 and extends in a planar shape along the X and Y directions. In this example, the top surface 25 is formed by the surface of the second semiconductor layer 23 opposite to the active layer 21. When viewed from the Z direction, the top surface 25 is formed, for example, in a rectangular shape (rectangular or square). In this example, the top surface 25 is formed in a rectangular shape when viewed from the Z direction. When viewed from the Z direction, the top surface 25 has a pair of first sides 25a and 25b extending along the Y direction (first direction) and a pair of second sides 25c and 25d extending along the X direction (second direction). The first sides 25a and 25b are the short sides of the top surface 25, and the second sides 25c and 25d are the long sides of the top surface 25. The top surface 25 has the above-mentioned recess 25A formed therein. The recess 25A is formed in a circular shape when viewed from the Z direction.

[0035] As shown in Fig. 5, the side surface 26 is formed as a curved surface that convexly extends inward of the mesa portion 20. Similarly, the side surface 12a of the protruding portion 12 is also formed as a curved surface that convexly extends inward of the protruding portion 12, and the side surface 26 is smoothly continuous with the side surface 12a. The side surface 26 being smoothly continuous with the side surface 12a means, for example, that no step is formed at the boundary between the side surface 26 and the side surface 12a. In this example, the side surface 26 and the side surface 12a are continuous with each other so as to form a single smoothly curved surface.

[0036] The side surface 26 has a pair of first surfaces 26a, 26b and a pair of second surfaces 26c, 26d (see FIG. 2). The pair of first surfaces 26a, 26b are connected to the top surface 25 at a pair of first sides 25a, 25b, respectively. That is, the first surface 26a is connected to the top surface 25 at the first side 25a, and the first surface 26b is connected to the top surface 25 at the first side 25b. When viewed from the Z direction, the pair of first surfaces 26a, 26b are located on both sides of the top surface 25 in the X direction.

[0037] The pair of second surfaces 26c, 26d are connected to the top surface 25 at a pair of second sides 25c, 25d, respectively. That is, the second surface 26c is connected to the top surface 25 at the second side 25c, and the second surface 26d is connected to the top surface 25 at the second side 25d. When viewed from the Z direction, the pair of second surfaces 26c, 26d are disposed on both sides of the top surface 25 in the Y direction.

[0038] 1 and 2, the light-emitting element 3 is disposed on the light-receiving element 4 so that the second surface 26c faces the light-receiving portion 402A and the second surface 26d faces the light-receiving portion 402B when viewed from the Z direction. That is, in this example, the second surface 26c of the mesa portion 20 forms an area facing the light-receiving portion 402A when viewed from the Z direction, and the second surface 26d forms an area facing the light-receiving portion 402B when viewed from the Z direction.

[0039] The metal layer 30 is formed of a metal material such as Cr, Au, Al, or Cu. The metal layer 30 has a first metal portion 31 (first portion) formed on the top surface 25 of the mesa portion 20, and a second metal portion 32 (second portion) formed on the side surface 26 of the mesa portion 20. The first metal portion 31 is electrically connected to the second semiconductor layer 23 and functions as an electrode. The first metal portion 31 includes an opening region 35 in which a light passage opening 35a (light emitting window) through which light from the active layer 21 passes is formed, and a connection region 36 for external connection.

[0040] In this example, the light passing opening 35a is formed in a circular shape. Light from the active layer 21 is emitted to the outside of the light-emitting element 3 through the light passing opening 35a. When viewed from the Z direction, the light passing opening 35a is formed closer to the first surface 26a (one of the pair of first surfaces 26a, 26b) than the center C of the top surface 25. That is, when viewed from the Z direction, the distance in the X direction from the center of the light passing opening 35a to the first surface 26a is shorter than the distance in the X direction from the center of the light passing opening 35a to the first surface 26b. The first metal portion 31 is formed over the entire surface of the top surface 25 except for a portion corresponding to the light passing opening 35a. The portion of the top surface 25 corresponding to the light passing opening 35a is a portion located inside the light passing opening 35a when viewed from the Z direction. The light passing opening 35a is formed at a position corresponding to the recess 25A described above (a position overlapping with the recess 25A when viewed from the Z direction).

[0041] The connection region 36 is a region to which external wiring such as wires that electrically connect the light-emitting element 3 to the outside is connected, and functions as an external connection terminal. In this example, the connection region 36 is set to a rectangular shape, and is located on the first surface 26b side of the opening region 35 when viewed from the Z direction.

[0042] The second metal portion 32 is formed integrally with the first metal portion 31 and extends along the side surface 26. The second metal portion 32 is formed on the side surface 26 via a second insulating portion 42 of the insulating layer 40 and a second resin portion 52 of the resin layer 50, which will be described later. In this example, the second metal portion 32 is formed on the side surface 26 around the entire periphery of the side surface 26 and extends in a rectangular ring shape when viewed from the Z direction. Specifically, the second metal portion 32 is formed integrally on the first surfaces 26a, 26b and the second surfaces 26c, 26d so as to be continuous around the entire periphery of the side surface 26. In the Z direction, the second metal portion 32 is formed so as to extend from the side surface 26 of the mesa portion 20 to the side surface 12a of the protrusion 12.

[0043] The insulating layer 40 is made of, for example, SiN or SiO 2、or AlN. The insulating layer 40 has a first insulating portion 41 formed on the top surface 25 of the mesa portion 20 and a second insulating portion 42 formed on the side surface 26 of the mesa portion 20. The first insulating portion 41 covers the exposed portion 25f of the mesa portion 20 from the light passage opening 35a. In this example, the first insulating portion 41 is formed on the edge of the recess 25A on the top surface 25 as well as on the bottom surface and inner peripheral surface of the recess 25A, and functions as a passivation film that protects the exposed portion 25f. When viewed from the Z direction, the first insulating portion 41 is formed, for example, in a circular shape.

[0044] The second insulating portion 42 is integrally formed on the top surface 25 and side surface 26 of the mesa portion 20, and on the side surface 12a of the protrusion 12. That is, in this example, the second insulating portion 42 has a top portion 43 formed on the top surface 25 and a main portion 44 formed on the side surface 26. The top portion 43 is formed on the outer edge region 25e of the top surface 25 and is formed in a rectangular ring shape when viewed from the Z direction. The outer edge region 25e is a rectangular ring-shaped region extending along the outer edge of the top surface 25 (first sides 25a, 25b and second sides 25c, 25d). The main portion 44 is formed from above the side surface 26 to above the side surface 12a. The main portion 44 is formed continuously around the entire periphery of the side surface 26. Specifically, the main portion 44 is integrally formed on the first surfaces 26a, 26b and second surfaces 26c, 26d so as to be continuous around the entire periphery of the side surface 26. The main body 44 extends along the side surface 26 and has a curved surface that is convex toward the inside of the mesa portion 20 .

[0045] The resin layer 50 is made of a resin material such as polyimide or epoxy. As shown in FIG. 5, the resin layer 50 has a first resin portion 51 formed on the top surface 25 of the mesa portion 20 and a second resin portion 52 formed on the side surface 26 of the mesa portion 20. The first resin portion 51 is formed on the top surface 25 via the top portion 43 of the second insulating portion 42. When viewed from the Z direction, the first resin portion 51 extends along the outer edge of the top surface 25 and is formed in a rectangular ring shape. The thickness of the first resin portion 51 is, for example, about 2 μm.

[0046] The second resin portion 52 is formed integrally with the first resin portion 51, and is formed on the side surface 26 of the mesa portion 20 via the main body 44 of the second insulating portion 42. In this example, the second resin portion 52 is formed continuously around the entire periphery of the side surface 26. Specifically, the second resin portion 52 is formed integrally on the first surfaces 26a, 26b and the second surfaces 26c, 26d so as to be continuous around the entire periphery of the side surface 26.

[0047] Next, the configuration of the resin layer 50 will be further described with reference to Figures 6 and 7. Figure 6 shows one example of the resin layer 50, and Figure 7 shows another example of the resin layer 50. The portion surrounded by a white dashed line in Figures 6 and 7 is the resin layer 50. The resin layer 50 may have the configuration shown in Figure 6 or the configuration shown in Figure 7.

[0048] The resin layer 50 has a surface 50a on the mesa portion 20 side and a surface 50b opposite to the mesa portion 20. The surface 50a extends along the top surface 25 and side surface 26 of the mesa portion 20. The portion of the surface 50a along the top surface 25 extends in the X and Y directions. The portion of the surface 50a along the side surface 26 has a curved shape that is convex toward the inside of the mesa portion 20. The entire surface 50a is in contact with the second insulating portion 42.

[0049] The surface 50b has a gentle shape that bulges out overall toward the opposite side from the mesa portion 20. The surface 50b includes a region 55 that is formed in a curved shape that is convex toward the opposite side from the mesa portion 20. The entire surface 50b is covered with the metal layer 30. That is, in this example, the entire surfaces of the resin layer 50 (surfaces 50a, 50b) are covered with the metal layer 30 and the second insulating portion 42 and are not exposed.

[0050] The second resin portion 52 of the resin layer 50 includes a thinned portion 56 whose thickness decreases toward the substrate 10. The thinned portion 56 is formed between the second metal portion 32 of the metal layer 30 and the second insulating portion 42 of the insulating layer 40. As a result, the distance between the second metal portion 32 and the second insulating portion 42 decreases toward the substrate 10. In this example, the second metal portion 32 and the second insulating portion 42 are in contact at the end of the thinned portion 56 on the substrate 10 side. The thickness (maximum thickness) of the second resin portion 52 is, for example, approximately 1 μm to 20 μm. The thickness of the second resin portion 52 is the thickness in a direction perpendicular to the Z direction. [Details of metal layer, insulating layer and resin layer]

[0051] 2, a space S is formed between the outer edge 41a of the first insulating portion 41 and the inner edge 42a of the second insulating portion 42 when viewed from the Z direction, and the top surface 25 is exposed from the insulating layer 40 in the space S. The first metal portion 31 of the metal layer 30 is in contact with the top surface 25 in the space S, and is electrically connected to the second semiconductor layer 23.

[0052] 2, the space S includes a first space S1 located closer to the first surface 26b than the outer edge 41a, and a second space S2 located closer to the first surface 26a than the outer edge 41a. As described above, the first insulating portion 41 is formed closer to the first surface 26a than the center C of the top surface 25 when viewed from the Z direction. Therefore, the first space S1 has a wider width in the X direction than the second space S2. The connection region 36 of the first metal portion 31 is located within the first space S1. In the connection region 36, the first metal portion 31 is formed directly on the top surface 25 of the mesa portion 20 without the insulating layer 40 or resin layer 50 interposed therebetween. In other words, the first resin portion 51 of the resin layer 50 is not formed between the connection region 36 and the top surface 25.

[0053] As described above, the second metal portion 32 of the metal layer 30 is formed on the side surface 26 of the mesa portion 20 via the second insulating portion 42 of the insulating layer 40 and the second resin portion 52 of the resin layer 50. When viewed from a direction perpendicular to the Z direction (e.g., the X direction or the Y direction), the second metal portion 32 overlaps (covers) the active layer 21, the first semiconductor layer 22, and the second semiconductor layer 23. In this example, when viewed from a direction perpendicular to the Z direction, the second metal portion 32 reaches the end of the mesa portion 20 on the substrate 10 side (the end of the side surface 26 on the substrate 10 side), and the end of the second metal portion 32 on the substrate 10 side is located on the side surface 12a of the protrusion 12. In other words, when viewed from a direction perpendicular to the Z direction, the second metal portion 32 overlaps not only the side surface 26 but also the side surface 12a.

[0054] 6 and 7, the portion of the second metal portion 32 formed on the resin layer 50 extends along the surface 50b of the resin layer 50, and has a gently sloping shape that bulges outward from the mesa portion 20. The portion of the second metal portion 32 formed on the region 55 of the surface 50b is formed in a curved shape that is convex toward the side opposite the mesa portion 20.

[0055] 1 and 2, in the reflective encoder 1, the second metal portion 32 on the second surface 26c of the mesa portion 20 is disposed between the second surface 26c and the light receiving portion 402A when viewed from the Z direction, and the second metal portion 32 on the second surface 26d of the mesa portion 20 is disposed between the second surface 26d and the light receiving portion 402B when viewed from the Z direction. This allows the second metal portion 32 to block light leaking from the second surfaces 26c and 26d, and prevents the leaked light from the second surfaces 26c and 26d from entering the light receiving portions 402A and 402B. [Action and effect]

[0056] In the light-emitting element 3, the metal layer 30 includes a first metal portion 31 disposed on the top surface 25 of the mesa portion 20 and electrically connected to the second semiconductor layer 23, as well as a second metal portion 32 formed integrally with the first metal portion 31 and extending along the side surface 26 of the mesa portion 20. The second metal portion 32 overlaps the active layer 21 when viewed from a direction perpendicular to the Z direction. This allows the second metal portion 32 to block light leaking from the side surface 26 of the mesa portion 20, thereby suppressing light leakage from the side surface 26 of the mesa portion 20. For example, if the metal layer 30 did not include the second metal portion 32, there is a risk that leaked light Lim from the side surface 26 would directly enter the light-receiving portion 402, as shown in FIG. 1 . On the other hand, in the light-emitting element 3 described above, the leaked light Lim is blocked by the second metal portion 32, thereby suppressing the leaked light Lim from entering the light-receiving portion 402. Furthermore, simply forming the metal layer 30 on the side surface 26 of the mesa portion 20 may result in failure to form the metal layer 30 satisfactorily. However, in this light-emitting device 3, the second metal portion 32 of the metal layer 30 is formed on the side surface 26 of the mesa portion 20 via the insulating layer 40 and the resin layer 50. This allows the second metal portion 32 of the metal layer 30 to be formed satisfactorily on the side surface 26 of the mesa portion 20, thereby effectively suppressing light leakage from the side surface 26 of the mesa portion 20. More specifically, for example, unevenness may be formed on the side surface 26 during the manufacture of the mesa portion 20. In this case, it may be difficult to form the second metal portion 32 on the side surface 26. Furthermore, the side surface 26 has a curved surface that is convex toward the inside of the mesa portion 20, which may also make it difficult to form the second metal portion 32 on the side surface 26. In contrast, in the light-emitting element 3, the second metal portion 32 is formed on the side surface 26 via the resin layer 50, so that the side surface 26 can be made to have a gentle shape, improving the adhesion of the second metal portion 32, and the second metal portion 32 can be favorably formed on the side surface 26. As described above, the light-emitting element 3 can suppress a decrease in detection accuracy when applied to the reflective encoder 1.

[0057] Generally, from the viewpoint of suppressing an increase in parasitic capacitance, it is not preferable to extend the metal layer 30 more than necessary, and therefore it is considered that a configuration in which the metal layer 30, which is electrically connected to the second semiconductor layer 23 at the top surface 25 of the mesa portion 20, extends to the side surface 26 of the mesa portion 20 is not adopted. In contrast, in the light-emitting element 3, the metal layer 30 is intentionally extended to reach onto the side surface 26 of the mesa portion 20, thereby suppressing light leakage from the side surface 26 of the mesa portion 20. Furthermore, if the first metal portion 31 and the second metal portion 32 in the metal layer 30 were formed separately from each other, there is a risk that the first metal portion 31 and the second metal portion 32 may come into unintended contact. However, in the light-emitting element 3, the first metal portion 31 and the second metal portion 32 are formed integrally, thereby suppressing the occurrence of such unintended contact.

[0058] When viewed from a direction perpendicular to the Z direction, the second metal portion 32 reaches the end of the mesa portion 20 on the substrate 10 side. This makes it possible to more effectively suppress light leakage from the side surface 26 of the mesa portion 20.

[0059] In the first metal portion 31, the light passage opening 35a is formed closer to the first surface 26a than the center C of the top surface 25 when viewed from the Z direction, and the second metal portion 32 is formed on the first surface 26a and the pair of second surfaces 26c, 26d. Since the light passage opening 35a is formed closer to the first surface 26a in the first metal portion 31, a wide connection region 36 for external connection can be secured. As a result, for example, it is possible to easily connect external wiring to the connection region 36. However, in this case, light is more likely to leak from the first surface 26a. In this regard, in the light-emitting element 3, the second metal portion 32 is formed on the first surface 26a and the pair of second surfaces 26c, 26d, so that light leakage from the side surface 26 of the mesa portion 20 can be reliably suppressed even in such cases.

[0060] The second metal portion 32 is formed over the entire periphery of the side surface 26 of the mesa portion 20. This makes it possible to more effectively suppress light leakage from the side surface 26 of the mesa portion 20.

[0061] The resin layer 50 includes a thinned portion 56 whose thickness decreases toward the substrate 10. This allows the surface 50b of the resin layer 50 opposite the mesa portion 20 to be smoothed, and the second metal portion 32 of the metal layer 30 can be more effectively formed on the side surface 26 of the mesa portion 20. Furthermore, light incident on the resin layer 50 from the side surface 26 of the mesa portion 20 can be efficiently attenuated. Specifically, light leaking from the side surface 26 of the mesa portion 20 into the resin layer 50 is attenuated by being repeatedly reflected between the side surface 26 of the mesa portion 20 and the second metal portion 32 of the metal layer 30. The thinner the resin layer 50, the narrower the gap between the side surface 26 of the mesa portion 20 and the second metal portion 32 of the metal layer 30, and the more times the leaked light is reflected, thereby allowing the leaked light to be efficiently attenuated. In the light-emitting element 3, the resin layer 50 includes a thinned portion 56 whose thickness decreases toward the substrate 10. This allows efficient attenuation of light incident on the resin layer 50 from the side surface 26 of the mesa portion 20. Furthermore, if light leaking from the side surface 26 can be efficiently attenuated, then even if an unintended hole is formed in the second metal portion 32, light leakage from the hole can be suppressed. Furthermore, if light leaking from the side surface 26 can be efficiently attenuated, then light from the active layer 21 can be suppressed from leaking from the side surface of the substrate 10. In the light-emitting element 3 of the above embodiment, light generated in the active layer 21 is absorbed by the substrate 10, so light does not leak from the side surface of the substrate 10. However, if the active layer 21 generates light in a wavelength band that is not absorbed by the substrate 10, it is effective to efficiently attenuate light leaking from the side surface of the substrate 10.

[0062] The side surface 26 of the mesa portion 20 is formed in a curved shape that convexly curves toward the inside of the mesa portion 20. In this case, it becomes difficult to form the second metal portion 32 of the metal layer 30 on the side surface 26 of the mesa portion 20. However, according to the light-emitting element 3, for the reasons described above, even in such a case, the second metal portion 32 can be successfully formed on the side surface 26.

[0063] The surface 50b of the resin layer 50 opposite to the mesa portion 20 includes a region 55 formed in a curved shape that is convex toward the side opposite to the mesa portion 20. This allows the second metal portion 32 of the metal layer 30 to be formed more satisfactorily on the side surface 26 of the mesa portion 20.

[0064] The metal layer 30 covers the entire surface 50b of the resin layer 50 opposite to the mesa portion 20. This makes it possible to more effectively suppress light leakage from the side surface 26 of the mesa portion 20. It also makes it possible to effectively suppress deterioration of the resin layer 50 due to contact with air.

[0065] The resin layer 50 has a first resin portion 51 formed on the top surface 25 of the mesa portion 20, but is not formed between the connection region 36 of the first metal portion 31 and the top surface 25 of the mesa portion 20. As a result, the resin layer 50 is formed not only on the side surface 26 of the mesa portion 20 but also on the top surface 25, allowing the resin layer 50 to be formed well. Furthermore, when the resin layer 50 is also formed on the top surface 25 of the mesa portion 20, the resin layer 50 is located on the connection portion between the top surface 25 and the side surface 26 of the mesa portion 20. As a result, the metal layer 30 can be formed more well on the resin layer 50. In addition, since the resin layer 50 is located on the connection portion between the top surface 25 and the side surface 26 of the mesa portion 20, the portion of the metal layer 30 located on the top surface 25 of the mesa portion 20 and the portion located on the side surface 26 of the mesa portion 20 are smoothly connected, thereby preventing the metal layer 30 from being broken. Furthermore, because the resin layer 50 is not formed between the connection region 36 of the first metal portion 31 and the top surface 25, it is possible to prevent a situation in which the presence of the resin layer 50 prevents an external wiring from being properly connected to the connection region 36. That is, if the resin layer 50 were formed between the first metal portion 31 and the top surface 25 in the connection region 36, the contact surface of the external wiring would become soft, which could make it difficult to connect the external wiring. In contrast, in the light-emitting element 3, the resin layer 50 is not formed between the connection region 36 of the first metal portion 31 and the top surface 25, it is possible to prevent such a situation from occurring.

[0066] When viewed from the Z direction, the first resin portion 51 of the resin layer 50 extends along the outer edge of the top surface 25 of the mesa portion 20. This allows the resin layer 50 to be formed not only on the side surface 26 of the mesa portion 20 but also on the top surface 25 of the mesa portion 20, making it possible to form the resin layer 50 well. Furthermore, because the first resin portion 51 extends along the outer edge of the top surface 25 of the mesa portion 20 when viewed from the Z direction, it is possible to prevent a situation in which the presence of the resin layer 50 prevents external wiring from being properly connected to the connection region 36.

[0067] The insulating layer 40 has a first insulating portion 41 formed on the top surface 25 of the mesa portion 20 and covering the exposed portion 25f from the light passing opening 35a. This allows the exposed portion 25f to be protected by the first insulating portion 41.

[0068] The first metal portion 31 is formed over the entire surface of the top surface 25 of the mesa portion 20 except for a portion corresponding to the light passage opening 35a. This makes it possible to ensure a wide connection region 36 for external connection in the first metal portion 31, thereby facilitating, for example, the connection of external wiring to the connection region 36. Furthermore, since the first metal portion 31 has a simpler shape than when the first metal portion 31 is formed as a complex wiring pattern, for example, it is possible to prevent unintended short circuits between the first metal portions 31.

[0069] In the reflective encoder 1, the light receiving unit 402 includes two light receiving units 402A and 402B arranged on both sides of the light emitting element 3 in a direction perpendicular to the Z direction, and the second metal portion 32 is formed on two regions (second surfaces 26c and 26d) on the side surface 26 of the mesa unit 20 that face the two light receiving units 402A and 402B when viewed from the Z direction. This allows the second metal portion 32 to block leakage light that enters the two light receiving units 402A and 402B arranged on both sides of the light emitting element 3 from the side surface 26 of the mesa unit 20. [Variations]

[0070] The present invention is not limited to the above-described embodiment. For example, the materials and shapes of each component are not limited to those described above, and various materials and shapes can be used. In the above-described embodiment, the top surface 25 of the mesa portion 20 is formed in a rectangular shape when viewed from the Z direction. However, the top surface 25 may be formed in a square, circular, or elliptical shape. In this case, the side surface 26 of the mesa portion 20 may be formed in a square ring shape, a circular ring shape, or an elliptical ring shape when viewed from the Z direction.

[0071] In the above embodiment, the mesa portion 20 has a current confinement structure constituted by the block layer 124 and the diffusion layer 125, but the mesa portion 20 does not have to have a current confinement structure. However, if a current confinement structure is provided, it is possible to narrow the light emitting point (emitted light) and suppress noise generation in the reflective encoder 1. The top surface 25 of the mesa portion 20 does not have to have a recess 25A, and the entire top surface 25 may be formed flat along the X and Y directions.

[0072] In the above embodiment, the light passing opening 35a is formed closer to the first surface 26a than the center C of the top face 25 when viewed from the Z direction, but the position of the light passing opening 35a is not limited. For example, the light passing opening 35a may be formed at the center C of the top face 25 when viewed from the Z direction. In the above embodiment, the light passing opening 35a is formed in a circular shape, but the light passing opening 35a may be formed in a rectangular or elliptical shape.

[0073] In the above embodiment, the insulating layer 40 had portions formed on the top surface 25 of the mesa portion 20 (the first insulating portion 41 and the top portion 43 of the second insulating portion 42), but the insulating layer 40 only needs to be formed on at least the side surface 26 of the mesa portion 20, and may have only the main body portion 44 of the second insulating portion 42.

[0074] In the above embodiment, the resin layer 50 has the first resin portion 51 formed on the top surface 25, but the resin layer 50 only needs to be formed on at least the side surface 26, and may have only the second resin portion 52. In the above embodiment, the resin layer 50 may be formed between the connection region 36 of the first metal portion 31 and the top surface 25 of the mesa portion 20.

[0075] In the above embodiment, the first metal portion 31 of the metal layer 30 was formed over the entire surface except for the portion corresponding to the light passage opening 35a on the top surface 25 of the mesa portion 20, but the first metal portion 31 may also be formed partially over the entire surface.

[0076] In the above embodiment, the second metal portion 32 of the metal layer 30 overlaps with the active layer 21, the first semiconductor layer 22, the second semiconductor layer 23, and the side surface 12a of the protrusion 12 when viewed from the Z direction, but it is sufficient that the second metal portion 32 overlaps with at least the active layer 21. For example, the end of the second metal portion 32 on the substrate 10 side may be located on the side surface of the first semiconductor layer 22 rather than on the side surface 12a of the protrusion 12.

[0077] In the above embodiment, the second metal portion 32 of the metal layer 30 is formed around the entire periphery of the side surface 26. However, the second metal portion 32 does not have to be formed around the entire periphery of the side surface 26. For example, the second metal portion 32 does not have to be formed on the first surface 26b, which is farthest from the light passage opening 35a when viewed from the Z direction among the first surfaces 26a, 26b and the second surfaces 26c, 26d. The region on the side surface 26 where the second metal portion 32 is formed may be determined based on its positional relationship with the light receiving unit 402. For example, as in the above embodiment, if two light receiving units 402A, 402B are arranged on both sides of the light emitting element 3 in the Y direction, the second metal portion 32 may be formed only on the two second surfaces 26c, 26d that face the two light receiving units 402A, 402B, respectively, when viewed from the Z direction, and the second metal portion 32 may not be formed on the first surfaces 26a, 26b. That is, the second metal portion 32 may be formed only on the region of the side surface 26 that faces (faces) the light receiving portion 402 where it is desired to suppress the incidence of leaked light when viewed from the Z direction.

[0078] In the above embodiment, the light receiving element 4 has multiple light receiving portions 402, but the number of light receiving portions 402 is not limited. The light receiving element 4 is required to have at least one light receiving portion 402. When there is one light receiving portion 402, the second metal portion 32 of the metal layer 30 may be formed only on an area of ​​the side surface 26 that faces the single light receiving portion 402 when viewed from the Z direction. In this case, as in the above embodiment, when applied to the reflective encoder 1, it is possible to suppress a decrease in detection accuracy. In the above embodiment, the reflective encoder 1 has only one light receiving element 4, but the reflective encoder 1 may have multiple light receiving elements 4.

[0079] When viewed from the Z direction, the light-emitting element 3 may be disposed such that the first surface 26a of the mesa portion 20 faces the light-receiving portion 402A, and the first surface 26b of the mesa portion 20 faces the light-receiving portion 402B. In this case, the second metal portion 32 of the metal layer 30 may be formed only on the first surfaces 26a and 26b, and may not be formed on the second surfaces 26c and 26d.

[0080] In the above embodiment, the side surface 26 of the mesa portion 20 is formed as a curved surface that protrudes toward the inside of the mesa portion 20, but the side surface 26 may be formed as a flat surface that is inclined with respect to the Z direction.

[0081] In the above embodiment, the metal layer 30 covers the entire surface 50b of the resin layer 50, but the metal layer 30 does not have to cover the entire surface 50b. That is, a part of the surface 50b may be exposed from the metal layer 30. In the above embodiment, the surface 50b includes the region 55 formed in a convex curved shape facing away from the mesa portion 20, but the surface 50b does not necessarily have to include the region 55.

[0082] The substrate 10 may not have the protrusion 12. In this case, for example, the substrate 10 may be formed into a rectangular plate shape (cuboid shape) as a whole, and the mesa portion 20 may be formed on the main surface of the substrate 10. The mesa portion 20 may have a vertical mesa structure formed into a rectangular shape in a cross section along the Z direction. In this case, the side surface 26 of the mesa portion 20 may extend along the Z direction.

[0083] The shape of the connection region 36 is not limited as long as it can be connected to external wiring such as wires. For example, the shape of the connection region 36 may be circular or elliptical. The connection region 36 may be the entire first metal portion 31 except for the light passage opening 35a. That is, in the above embodiment, the connection region 36 may be located over the entire top surface 25 of the mesa portion 20 except for the portion corresponding to the light passage opening 35a. [Explanation of symbols]

[0084] 1...reflective encoder, 2...rotating plate, 3...light-emitting element, 10...substrate, 20...mesa portion, 21...active layer, 22...first semiconductor layer, 23...second semiconductor layer, 25...top surface, 25a, 25b...first edge, 25c, 25d...second edge, 25f...exposed portion, 26...side surface, 26a, 26b...first surface, 26c, 26d...second surface, 30...metal layer, 31...first metal portion (first portion), 32...second metal portion (second portion), 35a...light passing opening, 35...opening region, 36...connection region, 40...insulating layer, 50...resin layer, 50b...surface, 55...region, 56...thinned portion, 202...reflective pattern, 402, 402A, 402B...light receiving portion, C...center, L...light.

Claims

1. A substrate; a mesa portion formed on the substrate, the mesa portion including an active layer that generates light, a first semiconductor layer that is disposed on the substrate side with respect to the active layer, and a second semiconductor layer that is disposed on the opposite side of the substrate with respect to the active layer; a metal layer having a first portion disposed on the top surface of the mesa portion and electrically connected to the second semiconductor layer, and a second portion formed integrally with the first portion and extending along a side surface of the mesa portion; an insulating layer formed on at least the side surface of the mesa portion; a resin layer formed on the insulating layer, the first portion includes a region in which a light passing opening through which the light passes is formed, and a region for external connection; the second portion is formed on the side surface of the mesa portion via the insulating layer and the resin layer, and overlaps at least the active layer when viewed from a direction perpendicular to a thickness direction of the substrate; The resin layer includes a portion whose thickness decreases toward the substrate side.

2. A substrate; a mesa portion formed on the substrate, the mesa portion including an active layer that generates light, a first semiconductor layer that is disposed on the substrate side with respect to the active layer, and a second semiconductor layer that is disposed on the opposite side of the substrate with respect to the active layer; a metal layer having a first portion disposed on the top surface of the mesa portion and electrically connected to the second semiconductor layer, and a second portion formed integrally with the first portion and extending along a side surface of the mesa portion; an insulating layer formed on at least the side surface of the mesa portion; a resin layer formed on the insulating layer, the first portion includes a region in which a light passing opening through which the light passes is formed, and a region for external connection; the second portion is formed on the side surface of the mesa portion via the insulating layer and the resin layer, and overlaps at least the active layer when viewed from a direction perpendicular to a thickness direction of the substrate; The surface of the resin layer opposite to the mesa portion includes a region formed in a curved shape that is convex toward the opposite side to the mesa portion.

3. A substrate; a mesa portion formed on the substrate, the mesa portion including an active layer that generates light, a first semiconductor layer that is disposed on the substrate side with respect to the active layer, and a second semiconductor layer that is disposed on the opposite side of the substrate with respect to the active layer; a metal layer having a first portion disposed on the top surface of the mesa portion and electrically connected to the second semiconductor layer, and a second portion formed integrally with the first portion and extending along a side surface of the mesa portion; an insulating layer formed on at least the side surface of the mesa portion; a resin layer formed on the insulating layer, the first portion includes a region in which a light passing opening through which the light passes is formed, and a region for external connection; the second portion is formed on the side surface of the mesa portion via the insulating layer and the resin layer, and overlaps at least the active layer when viewed from a direction perpendicular to a thickness direction of the substrate; a light-emitting element, wherein the resin layer has a portion formed on the top surface of the mesa portion, but is not formed between the region for external connection in the first portion and the top surface of the mesa portion.

4. A substrate; a mesa portion formed on the substrate, the mesa portion including an active layer that generates light, a first semiconductor layer that is disposed on the substrate side with respect to the active layer, and a second semiconductor layer that is disposed on the opposite side of the substrate with respect to the active layer; a metal layer having a first portion disposed on the top surface of the mesa portion and electrically connected to the second semiconductor layer, and a second portion formed integrally with the first portion and extending along a side surface of the mesa portion; an insulating layer formed on at least the side surface of the mesa portion; a resin layer formed on the insulating layer, the first portion includes a region in which a light passing opening through which the light passes is formed, and a region for external connection; the second portion is formed on the side surface of the mesa portion via the insulating layer and the resin layer, and overlaps at least the active layer when viewed from a direction perpendicular to a thickness direction of the substrate; the resin layer has a portion formed on the top surface of the mesa portion, The portion of the resin layer extends along the outer edge of the top surface of the mesa portion when viewed in the thickness direction of the substrate.

5. 5. The light-emitting element according to claim 1, wherein the second portion extends to an end of the mesa portion on the substrate side when viewed from a direction perpendicular to a thickness direction of the substrate.

6. the top surface of the mesa portion is formed in a rectangular shape having a pair of first sides extending along a first direction and a pair of second sides extending along a second direction perpendicular to the first direction when viewed from the thickness direction of the substrate, the side surface of the mesa portion has a pair of first surfaces respectively connected to the top surface at the pair of first sides, and a pair of second surfaces respectively connected to the top surface at the pair of second sides, In the first portion, the light passage opening is formed closer to one side of the pair of first surfaces than the center of the top surface when viewed in a thickness direction of the substrate, 6. The light-emitting element according to claim 1, wherein the second portion is formed on at least one of the pair of first surfaces and the pair of second surfaces.

7. 7. The light emitting device according to claim 1, wherein the second portion is formed over the entire periphery of the side surface of the mesa portion.

8. 8. The light-emitting element according to claim 2, wherein the resin layer includes a portion whose thickness decreases toward the substrate side.

9. 9. The light-emitting device according to claim 1, wherein the side surface of the mesa portion is formed in a curved shape that is convex toward the inside of the mesa portion.

10. 10. The light-emitting element according to claim 1, wherein the surface of the resin layer opposite to the mesa portion includes a region formed in a curved shape that is convex toward the opposite side to the mesa portion.

11. 11. The light-emitting element according to claim 1, wherein the metal layer covers the entire surface of the resin layer opposite to the mesa portion.

12. A light-emitting element described in any one of claims 1, 2, and 4 to 11, wherein the resin layer has a portion formed on the top surface of the mesa portion, but is not formed between the region for external connection in the first portion and the top surface of the mesa portion.

13. the resin layer has a portion formed on the top surface of the mesa portion, The light-emitting element according to any one of claims 1 to 3 and 5 to 12, wherein the portion of the resin layer extends along the outer edge of the top surface of the mesa portion when viewed in the thickness direction of the substrate.

14. 14. The light-emitting element according to claim 1, wherein the insulating layer has a portion formed on the top surface of the mesa portion to cover the portion exposed from the light passage opening.

15. 15. The light emitting device according to claim 1, wherein the first portion is formed over the entire top surface of the mesa portion except for a portion corresponding to the light passage opening.

16. The light-emitting element according to any one of claims 1 to 15, a rotating plate having a reflection pattern that reflects the light emitted from the light-emitting element; at least one light receiving unit that is disposed on the same side of the rotating plate as the light emitting element and that detects the light reflected by the reflection pattern; A reflective encoder, wherein the second portion is formed on at least an area of ​​the side surface of the mesa portion that faces the at least one light receiving portion when viewed in the thickness direction of the substrate.

17. the at least one light receiving unit includes two light receiving units disposed on both sides of the light emitting element in a direction perpendicular to a thickness direction of the substrate, The reflective encoder according to claim 16, wherein the second portion is formed on at least two regions on the side surface of the mesa portion that face the two light receiving portions when viewed in the thickness direction of the substrate.

Images