Light-emitting device

Abstract

To provide a light-emitting device that suppresses a decrease in deterioration of brightness at corner regions of an optical member emitting light.SOLUTION: A light-emitting device according to an embodiment, comprises: a substrate; a light-emitting element arranged on the substrate; a wavelength conversion member arranged on the light-emitting element and including a first surface; an optical member arranged apart from the first surface to an upper direction; a light-transmitting layer arranged between the wavelength conversion member and the optical member, and having a refractive index lower than that of the optical member; and a light-reflecting layer surrounding the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member. The optical member includes on the upper surface thereof, a first region and a second region adjacent to the first region. The first region includes a first exit surface of which an internal angle relative to the first surface is a first angle. The second region includes a second exit surface having a second angle smaller than the first angle. The second region is located in one corner region of the optical member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments relate to a light emitting device. [Background technology]

[0002] A light-emitting device can emit light with higher brightness by narrowing the light distribution of the emitted light. To narrow the light distribution of a light-emitting device, a structure is known in which a textured optical member is provided above a wavelength conversion layer disposed on a light-emitting element (see Patent Document 1). In the light-emitting device of Patent Document 1, an air layer is disposed between the wavelength conversion layer and the optical member, thereby realizing a light-emitting device with an even narrower light distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-531517 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the embodiment is to provide a light emitting device that suppresses a decrease in brightness in corner regions on the upper surface of an optical member. [Means for solving the problem]

[0005] A light emitting device according to an embodiment includes a substrate, a light emitting element disposed on the substrate, a wavelength converting member disposed on the light emitting element and having a first surface opposite to a surface facing the light emitting element, an optical member having an upper surface and disposed above and spaced apart from the first surface, a light transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member, and a light emitting element surrounding the light emitting element, the wavelength converting member, the light transmitting layer, and the optical member. and contacts the side surface of the wavelength conversion member and the side surface of the light-transmitting layer.and a light-reflective member. The optical member includes, on its upper surface, a first region including a first emission surface whose interior angle with respect to the first surface is a first angle, and a second region adjacent to the first region and including a second emission surface whose interior angle with respect to the first surface is a second angle. In a top view, the shape of the outer periphery of the optical member is a convex polygon, the convex polygon having a first side, a second side, and a first vertex where the first side intersects with the second side, and the second region is included in a region surrounded by straight lines connecting the first vertex, a first point on the first side that is closer to the first vertex than a point that bisects the first side, and a second point on the second side that is closer to the first vertex than a point that bisects the second side, The second area is a flat surface parallel to the first surface and is disposed continuously from the outer surface of the light reflecting member. . [Effects of the Invention]

[0006] According to this embodiment, it is possible to provide a light emitting device in which the decrease in brightness at the corner regions on the upper surface of the optical member is suppressed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic top view illustrating a light emitting device according to an embodiment. [Figure 2] 2 is a cross-sectional view taken along line II-II in FIG. 1, illustrating a schematic cross-sectional view of the light-emitting device according to the embodiment. [Figure 3] 3 is a cross-sectional view taken along the line III-III in FIG. 1, illustrating a schematic cross-sectional view of the light-emitting device according to the embodiment. [Figure 4A] FIG. 2 is a schematic enlarged top view of the IVA portion of FIG. 1. [Figure 4B] FIG. 4B is a schematic cross-sectional view taken along line IVB-IVB in FIG. 4A. [Figure 4C] FIG. 4B is a schematic perspective view showing an enlarged portion of FIG. 4A. [Figure 5A] FIG. 10 is a schematic enlarged top view of a light emitting device according to a modified example of the embodiment. [Figure 5B] FIG. 5B is a schematic cross-sectional view taken along line VB-VB in FIG. 5A. [Figure 6]5A and 5B are schematic cross-sectional views for explaining the operation of the light emitting device according to the embodiment. [Figure 7A] 5A to 5C are schematic diagrams for explaining the operation of the light emitting device according to the embodiment. [Figure 7B] 10A and 10B are schematic diagrams for explaining the operation of a light emitting device according to a comparative example. [Figure 7C] 5A to 5C are schematic diagrams for explaining the operation of the light emitting device according to the embodiment. [Figure 8A] FIG. 10 is a schematic enlarged top view showing a part of a light emitting device of a comparative example for explaining the operation of the light emitting device according to the embodiment. [Figure 8B] 8B is a schematic cross-sectional view showing a part of a light emitting device of a comparative example for explaining the operation of the light emitting device according to the embodiment, taken along the line VIIIB-VIIIB in FIG. 8A. FIG. [Figure 9A] FIG. 2 is a schematic enlarged top view illustrating a part of the light emitting device for explaining the operation of the light emitting device according to the embodiment. [Figure 9B] 9B is a schematic cross-sectional view illustrating a part of the light emitting device for explaining the operation of the light emitting device according to the embodiment, taken along line IXB-IXB in FIG. 9A. FIG. [Figure 10] FIG. 2 is a schematic top view illustrating the definition of parameters related to the luminance of the light emitting device according to the embodiment. [Figure 11] FIG. 11 is a graph showing relative luminance according to the parameter definitions of FIG. [Figure 12A] FIG. 10 is a schematic top view illustrating a light emitting device according to a modified example of the embodiment. [Figure 12B] FIG. 10 is a schematic top view illustrating a light emitting device according to a modified example of the embodiment. [Figure 13A] FIG. 10 is a schematic top view illustrating a light emitting device according to a modified example of the embodiment. [Figure 13B] FIG. 10 is a schematic top view illustrating a light emitting device according to a modified example of the embodiment. [Figure 14A] FIG. 10 is a schematic top view illustrating a light emitting device according to a modified example of the embodiment. [Figure 14B]FIG. 10 is a schematic top view illustrating a light emitting device according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and the drawings, elements similar to those described above with respect to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate. Note that cross-sectional views may be end views showing only the cut surface.

[0009] FIG. 1 is a schematic top view illustrating a light emitting device according to an embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and is a schematic cross-sectional view illustrating the light-emitting device according to the embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1, and is a schematic cross-sectional view illustrating the light-emitting device according to the embodiment. As shown in FIGS. 1 to 3, the light emitting device 1 according to this embodiment includes a substrate 10, a light emitting element 20, a wavelength converting member 30, an optical member 40, a light transmissive layer 60, and a light reflective member 70.

[0010] The light emitting element 20 is disposed on the substrate 10. The wavelength conversion member 30 is disposed on the light emitting element 20. The wavelength conversion member 30 has a first surface 31a, and the light emitting element 20 is disposed facing the surface of the wavelength conversion member 30 opposite to the first surface 31a. The light emitting element 20 has a light emitting surface 21S. The light emitting surface 21S is disposed at a position facing the surface of the wavelength conversion member 30 opposite to the first surface 31a. The light emitting surface 21S is a surface from which the light emitting element 20 mainly emits light. The first surface 31a and the light emitting surface 21S are parallel to each other.

[0011] In the following description, three-dimensional XYZ coordinates may be used. The XY plane is assumed to be a plane parallel to the first surface 31a and the light emitting surface 21S. The directions of the X and Y axes may be arbitrarily determined. The optical member 40 has a square periphery in the XY plane. In this case, the X axis is assumed to be parallel to a first side S1, which is one of the four sides of the periphery of the optical member 40, and the Y axis is assumed to be perpendicular to the first side S1 and parallel to a second side S2 adjacent to the first side S1. The Z axis is assumed to be perpendicular to the X and Y axes and to be positive in the direction from the surface of the wavelength conversion member 30 opposite the first surface 31a toward the first surface 31a. In this specification, "parallel" includes a range of approximately 0 degrees to ±5% between two lines, sides, surfaces, etc.

[0012] The positive direction of the Z axis is sometimes referred to as "top," "upper," or "upper," and the negative direction of the Z axis is sometimes referred to as "bottom," "lower," or "lower." When the light emitting device 1 is viewed from above, it is sometimes referred to as a "top view." When there is no distinction between viewing from above and viewing from below, it is sometimes referred to as an "XY plane view" or simply a "plane view." The direction along the Z axis is not necessarily the direction in which gravity acts. These are provided to make the explanation easier to understand, and are not limited to the actual terms "top," "upper," "upper," "lower," "lower," and "lower." The length in the Z axis direction is sometimes referred to as thickness.

[0013] As shown in FIG. 2, the optical member 40 is disposed above and spaced apart from the first surface 31a of the wavelength conversion member 30. The optical member 40 has an upper surface 40T. The optical member 40 is disposed so that the surface opposite to the upper surface 40T faces the first surface 31a. In the example shown in FIG. 2, the optical member 40 has the same shape as the wavelength conversion member 30 in a top view. The optical member 40 and the wavelength conversion member 30 are disposed so as to overlap each other. Note that the shape of the optical member 40 may be different from the shape of the wavelength conversion member 30 in a top view.

[0014] The light-transmitting layer 60 is disposed between the wavelength conversion member 30 and the optical member 40. The light-transmitting layer 60 has a refractive index lower than that of the optical member 40.

[0015] The light reflective member 70 surrounds the light emitting element 20, the wavelength conversion member 30, the light transmitting layer 60, and the optical member 40 in the XY plane view.

[0016] The configuration of the optical member 40 will now be described in detail. 1, the top surface 40T of the optical member 40 includes a first region 51 and a second region 52. The top surface 40T of the optical member 40 further includes a third region 53, a fourth region 54, and a fifth region 55.

[0017] In the example shown in FIG. 1, the first region 51 occupies most of the area including the central and peripheral portions of the upper surface 40T. The first region 51 includes a structure 100 shown in FIG. 4A, which will be described later. The structure 100 has an inclined surface (first emission surface) 101. As shown in FIG. 4B, the inclined surface 101 has a first angle φ1 with respect to an imaginary plane 31b parallel to the first surface 31a. The first angle φ1 is preferably 40° to 50°. A portion of the light transmitted through the optical member 40 is emitted from the inclined surface 101 of the first region 51.

[0018] As shown in FIG. 1 , the second region 52 is adjacent to the first region 51. The third region 53, the fourth region 54, and the fifth region 55 are also adjacent to the first region 51. The first region 51 is located between the second region 52 and the third region 53. The first region 51 is located between the second region 52 and the fourth region 54. The first region 51 is located between the third region 53 and the fifth region 55. The first region 51 is located between the fourth region 54 and the fifth region 55. In other words, the second region 52 to the fifth region 55 are not adjacent to one another.

[0019] The second region 52 may or may not include a structure. When the second region 52 includes a structure, the structure includes a light exit surface (second exit surface). This exit surface has a second angle φ2 with respect to the first surface 31a. FIG. 3 shows an imaginary plane 31b parallel to the first surface 31a, and shows that the exit surface has a second angle φ2 with respect to the plane 31b. The second angle φ2 is smaller than the first angle φ1, and preferably smaller than 40° with respect to the first surface 31a. When the second region 52 does not include a structure, a flat surface parallel to the first surface 31a (i.e., a surface at which the second angle with respect to the first surface 31a is preferably 0°, and may be inclined by approximately ±5°) serves as the light exit surface (second exit surface). A portion of the light passing through the optical member 40 is emitted to the external space from the second region 52 as the exit surface (second exit surface).

[0020] Like the second region 52, the third region 53 to the fifth region 55 may or may not include structures. The structures of the third region 53 to the fifth region 55 each have a light exit surface, and these exit surfaces have third to fifth angles with respect to the first surface 31a, respectively. The third to fifth angles are smaller than the first angle. Like the second angle φ2, the third to fifth angles are preferably smaller than 40° with respect to the first surface 31a. When the third region 53 to the fifth region 55 do not include structures, a flat surface parallel to the first surface 31a (i.e., a surface with the third to fifth angles of preferably 0° with respect to the first surface 31a, and may be inclined approximately ±5°) serves as the light exit surface (second exit surface). A portion of the light transmitted through the optical member 40 is emitted to the external space from the third region 53 to the fifth region 55 as the exit surface.

[0021] For example, the number of structures in each of the second region 52 to the fifth region 55 may be one or more. They may be square pyramids similar to the structures 100 in the first region 51. The emission surfaces of the second region 52 to the fifth region 55 correspond to inclined surfaces that constitute the square pyramids that are the structures of the second region 52 to the fifth region 55. As long as the second to fifth angles of these inclined surfaces with respect to the first surface 31a are smaller than the first angle, the shapes are not limited to square pyramids and may be other shapes as described below.

[0022] 1, the shape of the outer periphery (first periphery) of the optical member 40 in top view is a square with four vertices: a first vertex V1, a second vertex V2, a third vertex V3, and a fourth vertex V4. The shape of the outer periphery of the optical member 40 in top view is not limited to a square, but may be a rectangle, a trapezoid, or another quadrangle. The shape of the outer periphery of the optical member 40 is not limited to a quadrangle, but may be any convex polygon other than a quadrangle. Hereinafter, when expressing the perimeter of a figure, the symbols of the vertices of the figure are sometimes arranged clockwise. When referring to the perimeter, it is sometimes referred to simply as the perimeter, although it refers to the perimeter when viewed from above or in a plan view.

[0023] The periphery V1V2V4V3 of the optical member 40 consists of a first side S1, a second side S2, a third side S3, and a fourth side S4. The first side S1, the second side S2, the third side S3, and the fourth side S4 are line segments of the same length. The first side S1 and the fourth side S4 are parallel. The second side S2 and the third side S3 are parallel. The first side S1 and the fourth side are perpendicular to the second side S2 and the third side S3.

[0024] The first vertex V1 is the point where the first side S1 intersects with the second side S2. The second vertex V2 is the point where the first side S1 intersects with the third side S3. The third vertex V3 is the point where the second side S2 intersects with the fourth side S4. The fourth vertex V4 is the point where the third side S3 intersects with the fourth side.

[0025] The second region 52 is defined as the region included in the region R1 including the first vertex V1. The third region 53 is defined as the region included in the region R2 including the second vertex V2. The fourth region 54 is defined as the region included in the region R3 including the third vertex V3. The fifth region 55 is defined as the region included in the region R4 including the fourth vertex V4. More details are as follows.

[0026] Region R1 is a region surrounded by lines connecting first vertex V1, first point P1 on first side S1, and second point P2 on second side S2. Second region 52 is a region included in region R1. First point P1 is a point located closer to first vertex V1 than the point that bisects first side S1. Second point P2 is a point located closer to first vertex V1 than the point that bisects second side S2.

[0027] Region R2 is a region surrounded by lines connecting the second vertex V2, a third point P3 on the first side S1, and a fourth point P4 on the third side S3. A third region 53 is a region included in region R2. The third point P3 is a point located closer to the second vertex V2 than the point that bisects the first side S1. The fourth point P4 is a point located closer to the second vertex V1 than the point that bisects the third side S3.

[0028] Region R3 is a region surrounded by lines connecting the third vertex V3, the fifth point P5 on the second side S2, and the sixth point P6 on the fourth side S4. A fourth region 54 is a region included in region R3. The fifth point P5 is closer to the third vertex V3 than the point that bisects the second side S2. The sixth point P6 is closer to the third vertex V3 than the point that bisects the fourth side S4.

[0029] Region R4 is a region surrounded by lines connecting the fourth vertex V4, the seventh point P7 on the third side S3, and the eighth point P8 on the fourth side S4. A fifth region 55 is a region included in region R4. The seventh point P7 is closer to the fourth vertex V4 than the point that bisects the third side S3. The eighth point P8 is closer to the fourth vertex V4 than the point that bisects the fourth side S4.

[0030] 1, the vertices of the outer periphery defining the second region 52 include the first vertex V1. The outer periphery of the second region 52 has one side parallel to the first side S1 and one side parallel to the second side S2. The outer periphery of the second region 52 is a square.

[0031] In the example of FIG. 1, the third region 53 to the fifth region 55 have outer peripheries that are the same shape as the outer periphery of the second region 52. The third region 53 is a region included in R2. One of the vertices that define the shape of the outer periphery of the third region 53 is the second vertex V2. The shape of the outer periphery of the third region 53 has one side parallel to the first side S1 and one side parallel to the third side S3.

[0032] 1, the fourth region 54 is a region included in R3. One of the vertices defining the shape of the periphery of the fourth region 54 is the third vertex V3. The shape of the periphery of the fourth region 54 has one side parallel to the second side S2 and one side parallel to the fourth side S4.

[0033] 1, the fifth region 55 is a region included in R4. One of the vertices that define the shape of the periphery of the fifth region 55 is the fourth vertex V4. The shape of the periphery of the fifth region 55 has one side parallel to the third side S3 and one side parallel to the fourth side S4.

[0034] The third region 53 to the fifth region 55 each have a square outer periphery, and the area of the third region 53 to the fifth region 55 is equal to the area of the second region 52.

[0035] In the example shown in FIGS. 2 and 3, the optical member 40 has a positioning groove 41 on its side surface. The light-reflective member 70 has a positioning protrusion 71. The positioning groove 41 and the positioning protrusion 71 are each located at the same position on the Z axis. The positioning groove 41 can be fitted into the positioning protrusion 71. By fitting the positioning protrusion 71 into the positioning groove 41, the position of the lower surface of the optical member 40 from the first surface 31a can be accurately set. Therefore, the length of the light-transmitting layer 60 in the Z axis direction can be reliably secured.

[0036] The positioning of the optical member 40 relative to the wavelength conversion member 30 is not limited to the above example, and other means may be used. For example, the optical member 40 may have one or more support posts on the lower surface of the optical member 40. If the optical member 40 is rectangular in plan view and has four corners, the four support posts can be arranged at the four corners of the lower surface of the optical member 40. The outer periphery of each of the support posts arranged at the four corners may coincide with a part of the outer periphery of the optical member 40 in plan view, or may be separated from the outer periphery of the optical member 40. The shape of the support posts in plan view is, for example, rectangular or circular. By having the support posts in the optical member 40, the optical member 40 can be arranged on the wavelength conversion member 30 via the light-transmitting layer 60. The support posts arranged at the four corners can be arranged at any position in plan view. The pillars placed at the four corners may be, for example, positioned to overlap the second region 52 to the fifth region in a plan view, or may be positioned to partially overlap the second region 52 to the fifth region, or may be positioned not to overlap the second region 52 to the fifth region.

[0037] Alternatively, the positioning of the optical member 40 relative to the wavelength conversion member 30 can be achieved by devising a method for forming the light-reflecting member. For example, a first intermediate member is prepared in advance, in which the light-reflecting member is formed over the entire surface of the side surface of the optical member 40. In the first intermediate member, the light-reflecting member is formed so that the lower end of the light-reflecting member coincides with the lower surface of the optical member 40.

[0038] Furthermore, a second intermediate member is prepared by disposing the light emitting element 20 and the wavelength conversion member 30 on the substrate 10, and forming a light reflective member over the entire surface of each side surface of the light emitting element 20 and the wavelength conversion member 30. In the second intermediate member, when the light reflective member is formed, the position of the upper end of the light reflective member is set to be higher than the height of the first surface 31a of the wavelength conversion member 30 by the thickness of the light-transmitting layer 60.

[0039] Thereafter, by joining the lower end of the light-reflective member of the first intermediate member to the upper end of the light-reflective member of the second intermediate member, it is possible to form a light-emitting device in which the light-transmitting layer 60 is provided between the wavelength conversion member 30 and the optical member 40. According to this method, it is not necessary to precisely position the convex portions and grooves, and it is possible to easily form a light-emitting device.

[0040] FIG. 4A is a schematic enlarged top view of the IVA portion of FIG. FIG. 4B is a schematic cross-sectional view taken along line IVB-IVB in FIG. 4A. FIG. 4C is a schematic perspective view showing an enlarged portion of FIG. 4A. As shown in FIGS. 4A to 4C, the first region 51 of the optical member 40 includes a plurality of structures 100. In this example, the plurality of structures 100 are continuously arranged in a matrix with no gaps. The structures 100 are quadrangular pyramids. The quadrangular pyramid has a square shape when viewed in the XY plane. A plane 31b shown in FIG. 4B is a virtual plane parallel to the first surface 31a.

[0041] Structure 100 has four inclined surfaces 101 to 104. In the example of FIG. 4B, structure 100 is disposed on imaginary plane 31b parallel to first surface 31a. As shown in FIG. 4B, inclined surface 101 is located opposite inclined surface 102. Inclined surface 103 is located opposite inclined surface 104. Inclined surfaces 103 and 104 are disposed adjacent to inclined surfaces 101 and 102. Inclined surface (first emission surface) 101 is inclined at an interior angle of first angle φ1 with respect to imaginary plane 31b parallel to first surface 31a. Therefore, first angle φ1 is the interior angle with respect to first surface 31a. In other words, the interior angle with respect to first surface 31a is the angle formed between first emission surface 101 and imaginary plane 31b parallel to first surface 31a. Inclined surface 102, located opposite inclined surface 101, is tilted at the same first angle φ1 as inclined surface 101, but in a different direction from inclined surface 101. The remaining two inclined surfaces 103 and 104 are also tilted at the first angle φ1, but in different directions. The first angle φ1 of inclined surfaces 101 to 104 refers to the angle of a plane containing line segment 100B, where the inclined surface of structure 100 intersects with plane 31b, and vertex 100V of structure 100, relative to plane 31b.

[0042] (Modification of the arrangement of the structure 100) The structures 100 may be arranged continuously without gaps, or may be arranged discontinuously with gaps. FIG. 5A is a schematic enlarged top view of a light emitting device according to a modified example of the embodiment. FIG. 5B is a schematic cross-sectional view taken along line VB-VB in FIG. 5A. As shown in FIGS. 5A and 5B, the structures 100 are arranged regularly and spaced apart from each other. In the example shown in FIG. 5B, adjacent structures 100 are connected by a flat surface. The structures 100 include a square base with a side length of BL. The shortest distance SL between adjacent structures 100 is the separation distance between the two structures 100. In this example, BL=SL. Note that in the examples of FIGS. 4A to 4C, SL=0. The separation distance SL between the structures 100 can be set to any value, not limited to BL=SL or SL=0, as long as the light emitting element 20 emits light with a narrow light distribution.

[0043] In this embodiment, the structure 100 is a quadrangular pyramid. However, the shape of the structure 100 is not limited to this, and may be any other shape as long as narrowly distributed light can be emitted from the light-emitting device 1. For example, the structure may be a pyramid of another type, such as a triangular pyramid or a pentagonal pyramid, or may be a cone or an elliptical cone. Alternatively, the structure is not limited to a cone, but may be a truncated pyramid or a truncated cone, or may be a hemisphere or a semi-ellipsoid.

[0044] In the light emitting device 1 according to the embodiment, the second to fifth regions 52 to 55 are included in the corner regions of the outer periphery V1V2V4V3 on the upper surface 40T of the optical member 40. The first region 51 is a region that does not belong to any of the second to fifth regions 52 to 55 and is a region excluding the corner regions.

[0045] The first region 51 includes a plurality of regularly arranged structures 100. This allows the light incident on the optical member 40 to have a narrow light distribution.

[0046] The optical member 40 is made of a light-transmitting material having a refractive index higher than that of the light-transmitting layer 60, and is, for example, a light-transmitting resin or glass.

[0047] Next, the components of the light emitting device 1 other than the optical member 40 will be described in detail. The substrate 10 has wiring 12 formed on a base material 11. In this example, the base material 11 is a square plate-like member when viewed from above. The base material 11 is preferably formed of an insulating material with high thermal conductivity. The base material 11 is, for example, a ceramic substrate containing alumina or the like. The base material 11 is not limited to a ceramic substrate, and may be a glass epoxy substrate, a highly thermally conductive substrate containing polyimide resin fiber, or the like. Alternatively, the base material 11 may be a sapphire substrate, a silicon substrate with an insulating surface, or a metal substrate.

[0048] The light emitting element 20 includes a semiconductor structure and a pair of positive and negative electrodes electrically connected to the semiconductor structure on the underside of the semiconductor structure. The electrodes are connected to wiring 12. In the semiconductor structure, for example, a light emitting diode (LED) structure is realized by stacking at least a p-type semiconductor layer, a light emitting layer, and an n-type semiconductor layer.

[0049] The structure of the light-emitting layer may be a structure having a single active layer, such as a double heterostructure or a single quantum well structure (SQW), or a structure having a group of active layers, such as a multiple quantum well structure (MQW). The light-emitting layer can emit visible light or ultraviolet light. For example, visible light can include light ranging from at least blue to red. Examples of semiconductor structures including such a light-emitting layer include In x Al y Ga 1-x-y N (0≦x, 0≦y, x+y≦1).

[0050] Furthermore, the light-emitting element 20 may include two or more light-emitting layers in the semiconductor structure. For example, the semiconductor stack may include two or more light-emitting layers between an n-type semiconductor layer and a p-type semiconductor layer, or may include two or more repeated layers each having an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer stacked in that order. The two or more light-emitting layers may include, for example, light-emitting layers emitting different colors, or light-emitting layers emitting the same color. The same light emission color may be within a range that can be considered the same color in use, and may include variations of several nanometers in the dominant wavelength of each color. The combination of light emission colors can be appropriately selected. For example, when two light-emitting layers are included, combinations include blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or green light and red light.

[0051] In this example, a fixing member 24 is disposed around the upper periphery of the light emitting element 20 and between the light emitting element 20 and the wavelength conversion member 30. The fixing member 24 does not have to be disposed. The fixing member 24 is a solidified adhesive whose base material is a light-transmitting resin material, for example, an epoxy resin or a silicone resin. The fixing member 24 may contain particles or the like made of a resin material having a lower refractive index than the base material. The fixing member 24 can reflect light emitted laterally from the light emitting element 20 on its internal surface and guide it upward, thereby improving light extraction.

[0052] The wavelength conversion member 30 is disposed on the light emitting element 20. In a plan view, the wavelength conversion member 30 is larger than the light emitting element 20. In the wavelength conversion member 30, for example, a phosphor is dispersed in a base material made of a translucent resin material. The phosphor absorbs a portion of the light emitted from the light emitting element 20 and emits light of a different wavelength. In one example, the light emitting element 20 emits blue light, and the phosphor absorbs the blue light emitted from the light emitting element 20 and emits yellow light. As a result, the blue light and yellow light are mixed, and the light emitting device 1 emits white light.

[0053] The phosphor of the wavelength conversion member 30 is an yttrium-aluminum-garnet phosphor (for example, Y3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet phosphors (e.g., Lu3(Al,Ga)5O 12 :Ce), terbium aluminum garnet phosphors (e.g., Tb3(Al,Ga)5O 12 :Ce), CCA-based phosphors (e.g., Ca 10 (PO4)6C l2 :Eu), SAE-based phosphors (e.g., Sr4Al 14 O 25 :Eu), chlorosilicate phosphors (e.g., Ca8MgSiO 16 C l2 :Eu), β-sialon-based phosphors (e.g., (Si,Al)3(O,N)4:Eu) or α-sialon-based phosphors (e.g., Ca(Si,Al) 12 (O,N) 16:Eu), nitride-based phosphors such as SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2Si 0.99 Al 0.01 F 5.99 Fluoride-based phosphors such as 3.5MgO 0.5MgF2 GeO2:Mn) or MGF-based phosphors (for example, 3.5MgO 0.5MgF2 GeO2:Mn), phosphors having a perovskite structure (for example, CsPb(F,Cl,Br,I)3), or quantum dot phosphors (for example, CdSe, InP, AgInS2 or AgInSe2) can be used. The phosphor to be added to the base material of the wavelength conversion member may be one type of phosphor or multiple types of phosphors.

[0054] The light-transmitting layer 60 is a layer having a refractive index lower than that of the optical member 40. The light-transmitting layer 60 is, for example, a layer of air. The light-transmitting layer 60 is not limited to an air layer and may be made of other materials as long as the refractive index of the light-transmitting layer 60 is lower than that of the optical member 40. The light-transmitting layer 60 preferably has a refractive index close to that of a vacuum, and may contain other substances.

[0055] The thickness of the light-transmitting layer 60 may be thinner than the thicknesses of the optical member 40 and the wavelength conversion member 30, as long as it is possible to refract the light incident on the optical member 40 so that it travels upward.

[0056] 3, the light-reflective member 70 surrounds and covers the side surfaces of the light-emitting element 20, the fixing member 24, the wavelength conversion member 30, the light-transmitting layer 60, and the optical member 40. The light-reflective member 70 also covers the bottom surfaces of the light-emitting element 20 and the wavelength conversion member 30.

[0057] The light-reflecting member 70 reflects light emitted from the side surfaces of the light-emitting element 20, the fixing member 24, the wavelength conversion member 30, the light-transmitting layer 60, and the optical member 40, as well as from the bottom surfaces of the light-emitting element 20 and the wavelength conversion member 30. A portion of the light reflected by the light-reflecting member 70 travels upward, contributing to narrowing the light distribution of the light-emitting device 1.

[0058] The light-reflecting member 70 is formed, for example, from a resin material containing a light-diffusing material, and is white overall. Examples of light-diffusing materials that can be used include titanium oxide, silica, alumina, zinc oxide, and glass. Such a light-reflecting member 70 has a light reflectance of 60% or more, and preferably a reflectance of 90% or more.

[0059] In the above specific example, one light-emitting element 20 and one optical member 40 are applied to one substrate 10, but this is not limiting. For example, multiple light-emitting elements may be arranged on one substrate, and multiple optical members may be arranged on the multiple light-emitting elements. Furthermore, multiple light-emitting elements may be arranged on one substrate, and one optical member may be arranged on the multiple light-emitting elements. In either case, a light-transmitting layer of approximately equal thickness is arranged between the wavelength conversion member on the light-emitting element and the optical member.

[0060] (Operation of light emitting device 1) First, the operation of the light-transmitting layer 60 and the structure 100 will be described. FIG. 6 is a schematic cross-sectional view for explaining the operation of the light emitting device according to the embodiment. Fig. 6 shows the wavelength conversion member 30, the light-transmitting layer 60, the optical member 40, and the structure 100, which are parts of the light-emitting device 1 according to the embodiment. The arrows in Fig. 6 indicate how one light ray LL1, which is one of the lights passing through the light-emitting device 1, travels through each medium while being refracted. The dashed-dotted line in Fig. 6 is a straight line parallel to the optical axis and is the reference line for the angle of incidence and the angle of emission. The optical axis is parallel to the Z axis.

[0061] 6, the light ray LL1 emitted from the light emitting element 20 and incident on the wavelength conversion member 30 travels straight through the wavelength conversion member 30 and is incident on the light transmitting layer 60. The light ray LL1 incident on the light transmitting layer 60 travels straight through the light transmitting layer 60 and is incident on the optical member 40.

[0062] Since the refractive index of the light-transmitting layer 60 is lower than the refractive index of the optical member 40, the incident angle θ2 of the optical member 40 is smaller than the exit angle θ1 of the light-transmitting layer 60 according to Snell's law.

[0063] The light ray LL1 incident on the optical member 40 at the incident angle θ2 travels straight ahead and is emitted from the inclined surface 101 of the structure 100. The inclined surface 101 is set at the first angle φ1 so that the emitted light ray is directed upward, thereby realizing a narrow light distribution of the light emitting device 1.

[0064] The principle by which light emitted from the light-transmitting layer 60 is narrowed in light distribution by the optical member 40 will be specifically described using the operation of a light-emitting device of a comparative example. FIG. 7A is a schematic diagram for explaining the operation of the light emitting device according to the embodiment. FIG. 7B is a schematic diagram for explaining the operation of the light emitting device according to the comparative example. FIG. 7A schematically shows how light having a Lambertian light distribution characteristic is narrowed when the refractive index of the light-transmitting layer 60 is n=1 and the refractive index of the optical member 40 is n=1.51. 7B schematically shows the light distribution of light having Lambertian light distribution characteristics when a light-transmitting member having the same refractive index n=1.51 as optical member 40 is used instead of light-transmitting layer 60. In FIGS. 7A and 7B, LA represents the optical axis, which is shown to be parallel to the Z axis.

[0065] As shown in FIG. 7A, light with a Lambertian light distribution characteristic that has passed through a light-transmitting layer 60 with a refractive index n=1 is incident on an optical element 40 with a refractive index n=1.51, whereby the light distribution angle at the optical element 40 is narrowed to 41.5°.

[0066] As shown in FIG. 7B, light passing through a member with the same refractive index remains in a Lambertian distribution.

[0067] Next, it will be explained how narrowly distributed light is incident on the optical member 40, causing the light emitted from the structure 100 to be directed further upward, resulting in a narrower light distribution. FIG. 7C is a schematic diagram for explaining the operation of the light emitting device according to the embodiment. FIG. 7C shows an enlarged view of the structure 100, with two arrows indicating light rays LL3 and LL4 at two different angles. In the example of FIG. 7C, the first angle φ1 is 45°. LA is the optical axis, parallel to the Z axis. LA1 is a straight line perpendicular to the inclined surface 101, representing an auxiliary line having the first angle φ1 with respect to the optical axis LA, and is also a reference line for the emission angle of light emitted from the structure 100 and the incidence angle of light incident on the external space, relative to the inclined surface 101. The inclined surface 101 is at the first angle, and the first angle is 45°.

[0068] 7C, the refractive index of the structure 100 is greater than the refractive index of the external space, which is air, and therefore the angle of incidence into the external space is greater than the angle of emergence from the structure 100 of the light ray traveling within the structure 100. The light ray LL3 is a light ray traveling within the structure 100 at an angle of 0° to 45° with respect to the optical axis LA. Therefore, when it emerges from the inclined surface 101, the angle with respect to the optical axis becomes smaller. In other words, the light ray LL3 is refracted so as to travel further upward.

[0069] The light ray LL4 travels through the structure 100 at an angle of 45° to 90° with respect to the optical axis LA, and therefore the angle with respect to the optical axis LA becomes larger when it is emitted from the inclined surface 101. In other words, the light ray LL4 from the structure 100 has a smaller component of light traveling upward.

[0070] As described in relation to Fig. 7A, in the light-emitting device 1 according to this embodiment, the light traveling within the optical member 40 is distributed so as to have a narrower light distribution than the Lambertian light distribution. In this case, if the ratio between the refractive index of the optical member 40 and the refractive index of the light-transmitting layer 60 is as shown in Fig. 7A, the light in the optical member 40 has a narrower light distribution of 41.5°. Therefore, among the light traveling within the optical member 40, light rays with angles such as the light ray LL4 shown in Fig. 7C are hardly present within the optical member 40, and therefore most of the light traveling within the optical member 40 has a further narrower light distribution and is emitted from the structure 100 to the external space.

[0071] More generally, the angle of the inclined surface 101 is a first angle φ1, and in order for the light emitted from the inclined surface 101 to contain more components in the positive direction of the Z axis, it is desirable that the light emitted from the light-transmitting layer 60 be narrowly distributed at or below the first angle φ1 when it enters the optical element 40.

[0072] Next, when each of the second region 52 to the fifth region 55 includes the same structure 100a as the structure 100, it will be explained that emitting light via the structure 100a hinders narrowing of the light distribution, and it will be explained that the second region 52 to the fifth region 55 are made flat so as not to hinder narrowing of the light distribution. FIG. 8A is a schematic enlarged top view showing a part of a light emitting device of a comparative example, for explaining the operation of the light emitting device according to the embodiment. 8B is a schematic cross-sectional view showing a part of a light emitting device of a comparative example for explaining the operation of the light emitting device according to the embodiment, and is a cross-sectional view taken along line VIIIB-VIIIB in FIG. 8A. FIG. 9A is a schematic enlarged top view illustrating a part of the light emitting device for explaining the operation of the light emitting device according to the embodiment. 9B is a schematic cross-sectional view illustrating a part of the light emitting device for explaining the operation of the light emitting device according to the embodiment, and is a cross-sectional view taken along line IXB-IXB in FIG. 9A. For convenience of explanation, the operation of the light emitting device of the comparative example will be described first, and then the operation of the light emitting device according to the embodiment will be described. 8A and 8B show a portion of optical member 40, with an enlarged view of the portion corresponding to fourth region 54 of light emitting device 1 of the embodiment. The light emitting device of the comparative example shown in FIGS. 8A and 8B differs from light emitting device 1 of the embodiment in that fourth region 54 includes structure 100a. In other respects, the configuration of the light emitting device of the comparative example is the same as the configuration of the light emitting device of the embodiment.

[0073] 8A and 8B illustrate that the luminance of light in the region rb is lower than the luminance of light in the region ra. As shown in FIGS. 8A and 8B, the structure 100a has four inclined surfaces 101a to 104a. The arrangement and shape of the inclined surfaces 101a to 104a are the same as those of the inclined surfaces 101 to 104 described in relation to FIGS. 4A and 4B, respectively. In the structure 100a, one of the four interior angles of the bottom surface of the structure 100a coincides with the position of the third vertex V3. More specifically, the position of the vertex of the interior angle formed by the inclined surfaces 101a and 104a is the position of the third vertex V3. On the bottom surface of the structure 100a, the base side belonging to the inclined surface 101a is on the second side S2, and the base side belonging to the inclined surface 104a is on the fourth side S4.

[0074] Regions ra and rb are inclined surface regions that bisect inclined surfaces 101a to 104a. Region ra is made up of inclined surfaces 101a and 104a, and region rb is made up of inclined surfaces 102a and 103a. In other words, region ra is closer to third vertex V3 than region rb. Note that in FIG. 8A, the broken lines representing regions ra and rb and the solid lines representing inclined surfaces 101a to 104a are shifted in position to distinguish them from each other for ease of illustration.

[0075] The light emitted from the structure 100a is emitted from the light-emitting element 20 arranged closer to the center than the region including the structure 100a. As shown in Fig. 8B, the light emitted from the light-emitting element 20 travels from the positive side to the negative side of the X-axis.

[0076] Here, among the light rays constituting such light, light ray LL5 shown in Fig. 8B is incident on structure 100a. At this time, the angle of incidence on structure 100a is equal to or smaller than first angle φ1 with respect to the optical axis parallel to the Z axis. Therefore, as described in relation to Fig. 7C, in structure 100a, the light emitted from inclined surface 101 contains more components in the positive direction of the Z axis, and the emitted light has a light distribution characteristic that is directed upward.

[0077] Light ray LL6 shown in FIG. 8B has a smaller component in the positive direction of the Z axis than light ray LL5. Therefore, light ray LL6 is reflected by light reflective member 70 toward the positive direction of the X axis before entering structure 100a. Light ray LL6 reflected by light reflective member 70 is incident on structure 100a. At this time, the angle of incidence on structure 100a is greater than the first angle φ1 with respect to the optical axis parallel to the Z axis. Therefore, as described in relation to FIG. 7C, the component in the positive direction of the Z axis of the light emitted from inclined surface 102a is reduced.

[0078] Therefore, the brightness of the light emitted from the inclined surface 102a is lower than the brightness of the light emitted from the inclined surface 101a.

[0079] While the above description has been given of the behavior in the X-axis direction, light propagates while spreading on the XY plane, and the same behavior occurs in the Y-axis direction. That is, when viewed from above, the brightness of light emitted from the inclined surface 103a is lower than the brightness of light emitted from the inclined surface 104a. As a result, of the four inclined surfaces of the structure 100a, the brightness of light emitted from the inclined surfaces 101a and 104a closer to the third vertex V3 is higher, while the brightness of light emitted from the inclined surfaces 102a and 103a farther from the third vertex V3 is lower. As a result, the brightness of light emitted from the structure 100a included in the corner region is reduced overall.

[0080] The above description has been given for the fourth region 54, which is one corner region of the upper surface 40T. However, the same applies to the other corner regions, that is, the second region 52, the third region 53, and the fifth region 55. As described above, when a corner region of the upper surface 40T includes structures 100a having inclined surfaces, the brightness of light emitted from the inclined surfaces located away from the vertices (V1 to V4) of each corner region is lower than the brightness of light emitted from the inclined surfaces located close to the vertices (V1 to V4), thereby reducing the brightness of the structures 100a. The brightness of light emitted from each structure is lower in the structures 100a included in the corner regions that are more susceptible to the light reflected by the light reflecting member 70 than in the structures 100 included in the central portion of the upper surface 40T that are less susceptible to the light reflected by the light reflecting member 70.

[0081] 9A and 9B, in the light emitting device 1 of the embodiment, the corner region including the third vertex V3 does not include the structure 100a. In Fig. 9A and 9B, to facilitate comparison with Fig. 8A and 8B, the portions corresponding to the structure 100a shown in Fig. 8A and 8B are indicated by two-dot chain lines.

[0082] As shown in Fig. 9B, the light emitted from the light-emitting element 20 includes the light ray LL5 emitted from the optical member 40 and the light ray LL6 reflected by the light-reflective member 70, as in the case described in relation to Fig. 8B. The angles at which the light rays LL5 and LL6 travel are the same as in Fig. 8B.

[0083] Light ray LL5 shown in FIG. 9B is emitted from the optical element 40. Light ray LL6 shown in FIG. 9B is reflected by the light-reflective element 70 and then emitted from the optical element 40. Light rays LL5 and LL6 from the optical element 40 have higher brightness than light rays emitted from the structure 100a described in connection with FIGS. 8A and 8B. In a top view, the brightness of light directed toward the outside of the optical element 40, including light ray LL5, is approximately the same as the brightness of light directed toward the inside of the optical element 40, including light ray LL6. Note that, because light rays LL5 and LL6 shown in FIG. 9B are emitted into an external space having a smaller refractive index than the optical element 40, the angle of incidence from the optical element 40 to the external space is larger than the angle of emission from the optical element 40. Therefore, the components of light rays LL5 and LL6 emitted from the optical element 40 in the positive direction of the Z axis are both slightly smaller.

[0084] The same applies to the other corner regions, that is, second region 52, third region 53, and fifth region 55. Therefore, when the corner regions do not include structures 100a, the difference in luminance between the central portion and the corner regions is reduced, and light emitting device 1 with a narrower light distribution and improved luminance is realized.

[0085] The shapes and sizes of the second to fifth regions 52 to 55 are set appropriately depending on the shape of the optical member 40. The following case will be described as an example. FIG. 10 is a schematic top view illustrating the definition of parameters relating to the luminance of the light emitting device according to the embodiment. As shown in Fig. 10, lengths X1, X2, and X3 are defined. X1 is the length of one side of the light-emitting element 20. X2 is the shortest length of the first region 51 between the second region 52 and the third region 53. X3 is the length of one side of the second region 52 and the third region 53. The length of one side of the fourth region 54 and the fifth region 55 is also X3.

[0086] X1 is a given size of the light-emitting element 20, and is a fixed value in this example. X2 is a value that can be changed by changing the length X3 of one side of the second region 52 and the third region 53. Here, the second region 52 to the fifth region 55 are assumed to be squares of the same size. The luminance of the upper surface 40T is calculated with respect to the length X3 of one side of the squares that make up the second region 52 to the fifth region 55. For example, an optical simulator or the like can be used to calculate the luminance.

[0087] FIG. 11 is a graph showing relative luminance according to the parameter definitions of FIG. As shown in FIG. 11, the vertical axis of this graph represents the average luminance ratio. The average luminance ratio is the ratio of the average luminance to a reference value. The average luminance is the luminance obtained by simply averaging the luminance on the upper surface 40T. In this example, the reference value of the average luminance is the average luminance when the entire upper surface 40T includes regular and continuous structures 100 (i.e., the second region 52 to the fifth region 55 include structures identical to the structures 100). The higher the average luminance ratio, the narrower the light distribution, indicating that high luminance is obtained over a wider range of the upper surface 40T.

[0088] The horizontal axis of this graph represents the length of one side of the second region 52, which is the length X3 of one side of the second region 52 to the fifth region 55 shown in FIG.

[0089] In this graph, the average luminance ratio exceeds the reference value when X3 is greater than X3_1 and smaller than X3_2. The length X0 of one side of the optical member 40 is given, and the shortest length X2 of the first region 51 between the second region 52 and the third region 53 is given by X3_1 and X3_2. The value of X2 given by X3_1 and X3_2 is X1 × 0.9 to 1.1. In other words, by setting the length X3 of one side of the second region 52 to the fifth region 55 so that the shortest length X2 of the first region 51 between the second region 52 and the third region 53 is within the range of 90% to 110% of the length X1 of one side of the light-emitting element 20, a light-emitting device 1 with a narrower light distribution and higher luminance can be realized.

[0090] (Variation) 12A to 14B are schematic top views illustrating light emitting devices according to modified examples of the embodiment. It has been explained that the second to fifth regions 52 to 55 are squares each having sides parallel to the first to fourth sides S1 to S4 and including the first to fourth vertices V1 to V4 as their vertices. However, the shapes of the second to fifth regions are not limited to this. The light emitting devices of the following modified examples have the second to fifth regions of different shapes. Although the shape of the second region is shown in FIGS. 12A to 14B, the third to fifth regions also have the same shapes.

[0091] As shown in FIG. 12A, in the light-emitting device 1a according to the modified example, the upper surface 40T includes a second region 52a. The second region 52a is a square with a first vertex V1 as one of its vertices. The length of one side of the second region 52a is longer than half the length obtained by subtracting the length of one side of the light-emitting element 20 from the length of one side of the optical member 40 when viewed from above. Therefore, the second region 52a includes both the region outside the light-emitting element 20 and the region inside the light-emitting element 20 when viewed from above. As described with reference to FIGS. 10 and 11, the length of one side of the second region 52a is preferably such that the shortest length of the first region 51 between the second region and the third region is 90% or more of the length of one side of the light-emitting element 20 when the length of one side of the second region 52a is the same.

[0092] As shown in FIG. 12B, in a light emitting device 1b according to another modification, the top surface 40T includes a second region 52b. The second region 52b is square. The second region 52b does not include the first vertex V1. Therefore, the first region 51 is located between the first vertex V1 and the second region 52b. The first region 51 is also located between the first side S1 and the second region 52b. The first region 51 is also located between the second side S2 and the second region 52b.

[0093] The shapes of the second to fifth regions are not limited to squares. As shown in FIG. 13A, in a light-emitting device 1c according to another modification, the top surface 40T includes a second region 52c. The second region 52c is a rectangle having a first vertex V1 as one of its vertices. In this example, the second region 52c is a rectangle having a long side on the first side S1. When the second region is a rectangle, the long side of the rectangle does not necessarily have to be on the first side S1, but may also be on the second side S2.

[0094] 13B, in a light emitting device 1d according to another modification, the top surface 40T includes a second region 52d. The second region 52d has a shape obtained by combining two rectangles, one of which has the first vertex V1 as one of its vertices. The second region 52d has a shape obtained by combining a rectangle having a long side on the first side S1 and a rectangle having a long side on the second side S2.

[0095] The shapes of the second to fifth regions are not limited to squares or rectangles. 14A, in a light emitting device 1e according to another modification, the top surface 40T includes a second region 52e. The second region 52e is a right-angled isosceles triangle that includes the first vertex V1 as one of its vertices. The second region 52e is a right-angled isosceles triangle that has a side on the first side S1 and a side on the second side S2.

[0096] The shapes of the second to fifth regions are not limited to polygons such as triangles and squares. As shown in FIG. 14B, in a light emitting device 1f according to another modification, the top surface 40T includes a second region 52f. The second region 52f has a shape that includes the first vertex V1 as one of its vertices. The second region 52f has a linear side that includes the first vertex V1 on the first side portion S1, and a linear side that includes the first vertex V1 on the second side portion S2. The two sides of the second region 52f are connected by an arc at the end opposite the first vertex V1. The arc of the second region 52f is an arc of a circle whose center is on the first region 51 side. The shape of the second region is not limited to the above-described shape, and may be an arc of a circle whose center is on the second region side.

[0097] The shapes of the second to fifth regions do not need to be the same, and the shape of each region is determined so as to improve the average luminance when viewed from above. Even if the outer periphery of optical member 40 when viewed from above is a convex polygon other than a square, an appropriate shape for each corner region is selected depending on the shape of the convex polygon, etc.

[0098] The effects of the light emitting device 1 according to the embodiment will be described. The light-emitting device 1 according to the embodiment includes an optical member 40 and a light-transmitting layer 60 having a refractive index lower than that of the optical member 40. Therefore, the light distribution of light emitted from the light-transmitting layer 60 is narrowed by the optical member 40. Furthermore, the optical member 40 has a square outer periphery and includes a structure 100 in a first region 51, which is a region excluding at least the corner regions of the square. The structure 100 has an inclined surface 101 having a first angle φ1, so that the light whose light distribution has been narrowed in the optical member 40 is further narrowed before being emitted from the inclined surface 101.

[0099] In the light emitting device 1 according to this embodiment, the second to fifth regions 52 to 55 corresponding to the corners of the square periphery of the optical member 40 include inclined surfaces having a second angle φ2 smaller than the first angle φ1. Therefore, the luminance of light emitted from each inclined surface of the second to fifth regions 52 to 55 is not reduced compared to the luminance of light when the second to fifth regions 52 to 55 include the structures 100a, as described with reference to FIGS. 8A and 8B. Therefore, the reduction in luminance at the corner regions of the periphery of the optical member 40 is suppressed, and the average luminance of light emitted by the light emitting device 1 is improved.

[0100] In the above description, the second to fifth regions 52 to 55 are arranged discretely in the corner regions of a rectangular optical member in a plan view. However, as long as each of the second to fifth regions 52 to 55 includes a corner region, the same effect as described above can be achieved even if adjacent regions among the second to fifth regions 52 to 55 are joined together to form a single region. For example, the second and third regions 52 and 53 may extend in the X-axis direction and be joined to each other, and the fourth and fifth regions 54 and 55 may extend in the X-axis direction and be joined to each other. Alternatively, the second and fourth regions 52 and 54 may extend in the Y-axis direction and be joined to each other, and the third and fifth regions 55 may extend in the Y-axis direction and be joined to each other. In other words, the second to fifth regions 52 to 55 may be joined to each other, and the joined region may be arranged around the entire outer periphery of the optical member 40 in a plan view. In this case, the shape of the connected region in plan view can be a quadrangular ring.

[0101] It goes without saying that either or both of the wavelength conversion member 30 and the light-transmitting layer 60 do not need to be arranged, and even if they are not arranged, by satisfying the relationship between the first angle φ1 and the second angle φ2 in the first region 51 to the fifth region 55, it is possible to suppress a decrease in brightness in the corner regions.

[0102] According to the embodiment described above, it is possible to realize a light emitting device that suppresses a decrease in the brightness of emitted light in the corner regions of the optical member that emits light.

[0103] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other.

[0104] The embodiments include the following aspects.

[0105] (Appendix 1) A substrate; a light-emitting element disposed on the substrate; a wavelength converting member disposed on the light emitting element and having a first surface located on the opposite side to a surface facing the light emitting element; an optical member having an upper surface and disposed above and spaced apart from the first surface; a light-transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member; a light-reflecting member surrounding the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface whose interior angle with respect to the first surface is a first angle, and a second region adjacent to the first region including a second light exit surface whose interior angle with respect to the first surface is a second angle, From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting The second angle is smaller than the first angle.

[0106] (Appendix 2) 2. The light emitting device according to claim 1, wherein the second light exit surface is a flat surface with the second angle set to 0°.

[0107] (Appendix 3) 3. The light emitting device according to claim 1, wherein the second region is located outside the outer periphery of the light emitting element.

[0108] (Appendix 4) 3. The light emitting device according to claim 1, wherein the second region includes a region inside the outer periphery of the light emitting element.

[0109] (Appendix 5) the optical member includes a third region on the upper surface adjacent to the first region, From a top view, the convex polygon further has a third side and a second vertex where the first side intersects with the third side; The third region is the second vertex; a third point on the second side closer to the second vertex than a position that bisects the first side; a fourth point on the third side closer to the second vertex than a position that bisects the third side; 5. The light emitting device according to claim 1, wherein the light emitting element is included in an area surrounded by straight lines connecting the light emitting elements.

[0110] (Appendix 6) the optical member includes, on the upper surface, a fourth region and a fifth region adjacent to the first region; From a top view, the convex polygon further has a fourth side and a third vertex where the second side intersects with the fourth side; The fourth region is the third vertex; a fifth point on the second side closer to the third vertex than a position that bisects the second side; a sixth point on the fourth side that is closer to the third vertex than a position that bisects the fourth side; are included in the area bounded by the lines connecting the convex polygon further has a fourth vertex where the third side intersects with the fourth side, The fifth region is the fourth vertex; a seventh point closer to the fourth vertex than a position that bisects the third side; an eighth point closer to the fourth vertex than a position that bisects the fourth side; 6. The light-emitting device according to claim 5, which is included in an area surrounded by straight lines connecting the above.

[0111] (Appendix 7) In plan view, 7. The light emitting device according to any one of claims 1 to 6, wherein the periphery of the second region is a square or a triangle that includes the first vertex as a vertex.

[0112] (Appendix 8) the periphery of the light emitting element has a side parallel to the first side portion, the second region and the third region are each a square or a rectangle having a side parallel to the first side portion and a side perpendicular to the first side portion, 7. The light-emitting device according to claim 5, wherein the length of the first region parallel to the first side portion between the second region and the third region is within the range of 90% to 110% of the length of the side of the light-emitting element.

[0113] (Appendix 9) 9. The light emitting device according to claim 1, wherein the upper surface of the optical member includes a cone having the first light exit surface.

[0114] (Appendix 10) 10. The light emitting device according to claim 9, wherein a plurality of the cones are arranged in a continuous and regular pattern.

[0115] (Appendix 11) 11. The light emitting device according to any one of claims 1 to 10, wherein the light transmitting layer is an air layer and is disposed over the entire first surface of the wavelength conversion member.

[0116] (Appendix 12) A substrate; a light-emitting element disposed on the substrate and having a light-emitting surface; an optical member having an upper surface and disposed on the light exit surface; a light-reflecting member surrounding the light-emitting element and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region having an interior angle with respect to the light exit surface at a first angle, and a second region adjacent to the first region, the second region including a second light exit surface, the second region having an interior angle with respect to the light exit surface at a second angle; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting The second angle is smaller than the first angle. [Explanation of symbols]

[0117] 1, 1a to 1f light emitting device, 10 substrate, 12 wiring, 20 light emitting element, 30 wavelength conversion member, 31a first surface, 40 optical member, 40T upper surface, 41 positioning groove, 51 first region, 52, 52a to 52f second region, 53 third region, 54 fourth region, 55 fifth region, 60 light-transmitting layer, 70 light-reflective member, 71 positioning protrusion, 100 structure, 101 to 104 inclined surface

Claims

1. A substrate; a light-emitting element disposed on the substrate; a wavelength converting member disposed on the light emitting element and having a first surface located on the opposite side to a surface facing the light emitting element; an optical member having an upper surface and disposed above and spaced apart from the first surface; a light-transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member; a light-reflecting member that surrounds the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member and that is in contact with a side surface of the wavelength conversion member and a side surface of the light-transmitting layer; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region forming a first interior angle with respect to the first surface, and a second region adjacent to the first region and including a second light exit surface; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting The second region is a flat surface parallel to the first surface and is disposed continuously from the outer surface of the light reflecting member. Light-emitting device.

2. The light emitting device according to claim 1 , wherein the second region is positioned outside the outer periphery of the light emitting element.

3. A substrate, a light-emitting element disposed on the substrate; a wavelength converting member disposed on the light emitting element and having a first surface located on the opposite side to a surface facing the light emitting element; an optical member having an upper surface and disposed above and spaced apart from the first surface; a light-transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member; a light-reflecting member surrounding the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region forming a first interior angle with respect to the first surface, and a second region adjacent to the first region and including a second light exit surface; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting the second region is a flat surface parallel to the first surface and is disposed continuously from the outer surface of the light reflecting member; The second region includes a region inside the outer periphery of the light-emitting element. Light-emitting device.

4. the optical member includes a third region on the upper surface adjacent to the first region, From a top view, the convex polygon further has a third side and a second vertex where the first side intersects with the third side; The third region is the second vertex; a third point on the second side closer to the second vertex than a position that bisects the first side; a fourth point on the third side portion that is closer to the second vertex than a position that bisects the third side portion; 2. The light emitting device according to claim 1, wherein the light emitting element is included in an area surrounded by lines connecting the light emitting elements.

5. the optical member includes, on the upper surface, a fourth region and a fifth region adjacent to the first region; From a top view, the convex polygon further has a fourth side and a third vertex where the second side intersects with the fourth side, The fourth region is the third vertex; a fifth point on the second side closer to the third vertex than a position that bisects the second side; a sixth point on the fourth side closer to the third vertex than a position that bisects the fourth side; are included in the area bounded by the lines connecting the convex polygon further has a fourth vertex where the third side intersects with the fourth side, The fifth region is the fourth vertex; a seventh point closer to the fourth vertex than a position that bisects the third side; an eighth point closer to the fourth vertex than a position that bisects the fourth side; 5. The light emitting device according to claim 4, wherein the light emitting element is included in an area surrounded by straight lines connecting the light emitting elements.

6. A substrate, a light-emitting element disposed on the substrate; a wavelength converting member disposed on the light emitting element and having a first surface located on the opposite side to a surface facing the light emitting element; an optical member having an upper surface and disposed above and spaced apart from the first surface; a light-transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member; a light-reflecting member surrounding the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region forming a first interior angle with respect to the first surface, and a second region adjacent to the first region and including a second light exit surface; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting the second region is a flat surface parallel to the first surface and is disposed continuously from the outer surface of the light reflecting member; In plan view, The periphery of the second region is a square or a triangle that includes the first vertex as a vertex. Light-emitting device.

7. A substrate; a light-emitting element disposed on the substrate; a wavelength converting member disposed on the light emitting element and having a first surface located on the opposite side to a surface facing the light emitting element; an optical member having an upper surface and disposed above and spaced apart from the first surface; a light-transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member; a light-reflecting member surrounding the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region forming a first interior angle with respect to the first surface, and a second region adjacent to the first region and including a second light exit surface; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting the second region is a flat surface parallel to the first surface and is disposed continuously from the outer surface of the light reflecting member; the optical member includes a third region on the upper surface adjacent to the first region, From a top view, the convex polygon further has a third side and a second vertex where the first side intersects with the third side; The third region is the second vertex; a third point on the second side closer to the second vertex than a position that bisects the first side; a fourth point on the third side portion that is closer to the second vertex than a position that bisects the third side portion; are included in the area bounded by the lines connecting the periphery of the light-emitting element has a side parallel to the first side portion, the second region and the third region are each a square or a rectangle having a side parallel to the first side portion and a side perpendicular to the first side portion, a length of the first region parallel to the first side portion between the second region and the third region within a range of 90% to 110% of the length of the side of the light emitting element; Light-emitting device.

8. A substrate; a light-emitting element disposed on the substrate; a wavelength converting member disposed on the light emitting element and having a first surface located on the opposite side to a surface facing the light emitting element; an optical member having an upper surface and disposed above and spaced apart from the first surface; a light-transmitting layer disposed between the wavelength converting member and the optical member and having a refractive index lower than that of the optical member; a light-reflecting member surrounding the light-emitting element, the wavelength conversion member, the light-transmitting layer, and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region forming a first interior angle with respect to the first surface, and a second region adjacent to the first region and including a second light exit surface; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting the second region is a flat surface parallel to the first surface and is disposed continuously from the outer surface of the light reflecting member; the upper surface of the optical member includes a cone having the first exit surface; Light-emitting device.

9. The light emitting device according to claim 8 , wherein a plurality of the cones are arranged in a continuous and regular pattern.

10. The light emitting device according to claim 1 , wherein the light transmitting layer is a layer of air, and the light transmitting layer is disposed over the entire first surface of the wavelength converting member.

11. A substrate; a light-emitting element disposed on the substrate and having a light-emitting surface; an optical member having an upper surface and disposed on the light exit surface; a light-reflecting member surrounding the light-emitting element and the optical member; Equipped with the upper surface of the optical member includes a first region including a first light exit surface, the first region forming a first interior angle with respect to the light exit surface, and a second region adjacent to the first region and including a second light exit surface; From a top view, the outer periphery of the optical member is a convex polygon; The convex polygon is a first side portion, a second side portion, and a first vertex where the first side portion intersects with the second side portion; The second region is the first vertex; a first point on the first side portion that is closer to the first vertex than a point that bisects the first side portion; a second point on the second side closer to the first vertex than a point that bisects the second side; are included in the area bounded by the lines connecting The second region is a flat surface parallel to the light exit surface and is disposed continuously from the outer surface of the light reflecting member. Light-emitting device.

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