Light-emitting device

Abstract

To improve optical coupling efficiency between a light emitting device and a light guide plate.SOLUTION: A light emitting device includes a first light emitting element 121 and a second light emitting element 122 arranged along a first direction, at least one light-transmissive member 131A, 131B covering the first light emitting element and the second light emitting element, and a light reflecting member 140A. The light-transmissive member has a first surface 131a and a second surface 132a exposed from the light reflecting member. The first surface has a projecting shape including a first apex 131t in a first cross section that includes the first direction and is perpendicular to the top surface of the first light emitting element, and the second surface has a projecting shape including a second apex 132t in the first cross section. The reflecting member has a first protrusion portion 141 located between the first surface and the second surface in the first direction, the first protrusion portion including a portion located above the first apex of the first surface and the second apex of the second surface in the first cross section.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a light emitting device. [Background technology]

[0002] Light-emitting devices including LEDs as a part thereof are widely used as light sources for backlights of liquid crystal display devices. For example, the following Patent Document 1 discloses a side-emitting type LED package including two LEDs. Such a side-emitting type LED package is used with its light-emitting surface facing a side surface of a light guide plate. Light from the LED package enters the light guide plate from the side surface of the light guide plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-036713 A [Patent Document 2] JP 2020-167396 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a backlight that includes a light guide plate as a part thereof, there is a demand for efficient incidence of light from a light emitting device on the light guide plate. [Means for solving the problem]

[0005] A light emitting device according to an embodiment of the present disclosure includes a first light emitting element and a second light emitting element arranged along a first direction, each having an upper surface and a side surface, at least one light transmissive member having a side surface and covering the upper surface of the first light emitting element and the upper surface of the second light emitting element, and a light reflective member in contact with at least a portion of the side surface of the first light emitting element, at least a portion of the side surface of the second light emitting element, and the side surface of the light transmissive member, the light transmissive member having a first surface and a second surface exposed from the light reflective member, the first surface and the second surface being located above the first light emitting element and above the second light emitting element, respectively, the first surface including the first direction and perpendicular to the upper surface of the first light emitting element. In a first cross section, the light-reflective member has a convex shape including a first apex, and the second surface has a convex shape including a second apex in the first cross section, and an upper surface of the light-reflective member has a pair of first regions located outside the first surface of the light-transmitting member in a second direction perpendicular to the first direction and each of the first regions is aligned with the first surface, and a pair of second regions located outside the second surface of the light-transmitting member in the second direction and each of the second regions is aligned with the second surface, and the light-reflective member has a first convex portion located between the first surface and the second surface in the first direction and including a portion located above the first apex of the first surface and the second apex of the second surface in the first cross section. Effect of the Invention

[0006] According to the embodiment of the present disclosure, a light emitting device capable of efficiently directing light into a light guide plate can be provided. [Brief description of the drawings]

[0007] [Figure 1] 1 is a top perspective view diagrammatically illustrating an example of a light emitting device according to a first embodiment of the present disclosure. [Diagram 2] 2 is a schematic bottom perspective view of the light emitting device shown in FIG. 1. [Diagram 3] FIG. 3 is a schematic cross-sectional view of the light-emitting device shown in FIGS. 1 and 2. [Figure 4]3 is a schematic YZ cross-sectional view of the light emitting device cut at a position passing through the first light emitting element. FIG. [Diagram 5] 2 is a schematic YZ cross-sectional view of the light emitting device when cut so as to include a first apex of a first surface. FIG. [Figure 6] 4 is a schematic YZ cross-sectional view of the light emitting device when cut so as to include the second apex of the second surface. FIG. [Figure 7] FIG. 1 is a schematic diagram illustrating a backlight having a light-emitting device according to an embodiment of the present disclosure. [Figure 8] FIG. 4 is a top perspective view diagrammatically illustrating an example of a light emitting device according to a second embodiment of the present disclosure. [Figure 9] FIG. 9 is a schematic top view of the light emitting device shown in FIG. [Figure 10] FIG. 10 is a schematic cross-sectional view of the light emitting device shown in FIGS. 8 and 9. [Figure 11] 11 is a schematic cross-sectional view showing another modified example of the light emitting device according to the embodiment of the present disclosure. FIG. [Figure 12] 11 is a schematic cross-sectional view showing still another modified example of the light emitting device according to the embodiment of the present disclosure. FIG. [Figure 13] 11 is a schematic cross-sectional view showing still another modified example of the light emitting device according to the embodiment of the present disclosure. FIG. [Figure 14] 13 is a schematic cross-sectional view showing yet another modified example of the light emitting device according to the embodiment of the present disclosure. FIG. [Figure 15] 1 is a diagram showing an example of the appearance of a light emitting device according to an embodiment of the present disclosure, as viewed from the bottom surface side of a substrate. [Figure 16] 1 is a diagram showing an example of the appearance of a light emitting device according to an embodiment of the present disclosure, as viewed from the side of a surface that faces a wiring board. [Figure 17] 1 is a schematic top view of an aggregate substrate on which light-emitting elements according to an embodiment of the present disclosure are mounted. [Figure 18] 3 is a schematic bottom view of an aggregate substrate on which light-emitting elements according to an embodiment of the present disclosure are mounted. FIG. [Figure 19] 1A to 1C are schematic top views illustrating an exemplary method for manufacturing a light emitting device according to an embodiment of the present disclosure. [Figure 20] 5A to 5C are schematic cross-sectional views illustrating an exemplary method for manufacturing a light-emitting device according to an embodiment of the present disclosure. [Figure 21] 5A to 5C are schematic cross-sectional views illustrating an exemplary method for manufacturing a light-emitting device according to an embodiment of the present disclosure. [Figure 22] 5A to 5C are schematic cross-sectional views illustrating an exemplary method for manufacturing a light-emitting device according to an embodiment of the present disclosure. [Figure 23] 1A to 1C are schematic top views illustrating an exemplary method for manufacturing a light emitting device according to an embodiment of the present disclosure. [Figure 24] 5A to 5C are schematic cross-sectional views illustrating an exemplary method for manufacturing a light-emitting device according to an embodiment of the present disclosure. [Diagram 25] 4 is a schematic diagram showing the calculation results of irradiance inside the light guide plate for the sample of Example 1. FIG. [Figure 26] FIG. 11 is a schematic diagram showing the calculation results of irradiance inside the light guide plate for the sample of Example 2. [Figure 27] 10 is a schematic diagram showing calculation results of irradiance inside the light guide plate for the sample of Reference Example 1. FIG. [Figure 28] 13 is a schematic diagram showing the calculation results of irradiance inside the light guide plate for the sample of Reference Example 2. FIG. [Figure 29] 13 is a schematic diagram showing the calculation results of irradiance inside the light guide plate for the sample of Reference Example 3. FIG. [Diagram 30] 13 is a schematic diagram showing the calculation results of irradiance inside the light guide plate for the sample of Reference Example 4. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. The following embodiments are merely examples, and the light-emitting device according to the present disclosure is not limited to the following embodiments. For example, the numerical values, shapes, materials, steps, and the order of the steps shown in the following embodiments are merely examples, and various modifications are possible as long as no technical contradictions occur. Each embodiment described below is merely an example, and various combinations are possible as long as no technical contradictions occur.

[0009] The dimensions, shapes, etc. of components shown in the drawings may be exaggerated for clarity and may not reflect the dimensions, shapes, and size relationships between components in an actual light-emitting device. In addition, in order to avoid overly complicated drawings, some elements may be omitted and shown in schematic form, or an end view showing only a cut surface may be shown as a cross-sectional view.

[0010] In the following description, components having substantially the same functions are indicated by common reference symbols, and descriptions may be omitted. In the following description, terms indicating a specific direction or position (for example, "upper", "lower", "right", "left" and other terms including these terms) may be used. However, these terms are merely used for the sake of clarity of the relative direction or position in the referenced drawings. As long as the relationship of the relative direction or position by terms such as "upper" and "lower" in the referenced drawings is the same, the arrangement may not be the same as that in the referenced drawings in drawings other than this disclosure, in actual products, manufacturing devices, etc. In this disclosure, "parallel" includes cases where two straight lines, sides, faces, etc. are in the range of about 0° to ±5°, unless otherwise specified. In addition, in this disclosure, "perpendicular" or "orthogonal" includes cases where two straight lines, sides, faces, etc. are in the range of about 90° to ±5°, unless otherwise specified.

[0011] (First embodiment) 1 and 2 are schematic diagrams showing the appearance of a light-emitting device according to a first embodiment of the present disclosure. For convenience of explanation, arrows indicating mutually orthogonal X, Y, and Z directions are also shown in Fig. 1 and Fig. 2. Arrows indicating these directions may also be shown in other drawings of the present disclosure. In this specification, the X direction in the drawings may be referred to as the first direction.

[0012] FIG. 3 shows a schematic cross section of the light emitting device 100A shown in FIG. 1 and FIG. 2. FIG. 3 corresponds to a schematic cross section of the light emitting device 100A cut parallel to the ZX plane near the center of the light emitting device 100A. As shown in FIG. 3, the light emitting device 100A includes a first light emitting element 121 and a second light emitting element 122. The first light emitting element 121 has an upper surface 121a and a side surface 121c. Similarly, the second light emitting element 122 has an upper surface 122a and a side surface 122c. The first light emitting element 121 and the second light emitting element 122 each have an electrode 24 on a lower surface opposite to the upper surface. FIG. 3 shows the structure of the light emitting device 100A in a cross section including the first direction and perpendicular to the upper surface 121a of the first light emitting element 121. In this specification, the ZX cross section may be referred to as the first cross section.

[0013] 1 to 3, the light emitting device 100A further includes a substrate 110 supporting these light emitting elements. The substrate 110 has an upper surface 110a, and the first light emitting element 121 and the second light emitting element 122 are disposed on the upper surface 110a of the substrate 110 along the X direction (first direction) in the figures.

[0014] As shown in Fig. 3, the light emitting device 100A includes a first light-transmissive member 131A, a second light-transmissive member 132A, and a light-reflective member 140A in addition to the first light emitting element 121, the second light emitting element 122, and the substrate 110. In the configuration illustrated in Fig. 3, the light emitting device 100A may further include a first light-transmissive joining member 151 that joins the first light-transmissive member 131A to the upper surface 121a of the first light emitting element 121, and a second light-transmissive joining member 152 that joins the second light-transmissive member 132A to the upper surface 122a of the second light emitting element 122. Note that here, the Z direction in the figure is the direction from the first light emitting element 121 toward the first light-transmissive member 131A, and the normal to the upper surface 121a of the first light emitting element 121 is approximately parallel to the Z direction.

[0015] The first light-transmissive member 131A has a first surface 131a located above the upper surface 121a of the first light-emitting element 121. The first surface 131a constitutes at least a part of the upper surface of the first light-transmissive member 131A. In the example shown in Fig. 3, the first surface 131a is entirely exposed from the light-reflective member 140A. As can be seen from Figs. 1 and 2, here, the first surface 131a has a rectangular shape that is longer in the X direction compared to the Y direction in the figure.

[0016] The first surface 131a has a convex shape that rises on the side opposite to the first light-emitting element 121, and has a first apex 131t at a position farthest from the first light-emitting element 121. In the configuration illustrated in FIGS. 1 to 3, the first surface 131a is a curved surface that rises on the side opposite to the first light-emitting element 121.

[0017] 3, it is preferable that the position of the first apex 131t in the first cross section (ZX cross section) coincides with the position of the center of the light emitting element 121. This can reduce the difference in the amount of light emitted from both ends of the first surface 131a in the X direction. It is also more preferable that the first surface 131a is symmetrical about the first apex 131t in the first cross section (ZX cross section). This can further reduce the difference in the amount of light emitted from both ends of the first surface 131a in the X direction.

[0018] Similar to the first light-transmissive member 131A, the second light-transmissive member 132A also has a second surface 132a located above the upper surface 122a of the second light-emitting element 122. The second surface 132a constitutes at least a part of the upper surface of the second light-transmissive member 132A. Similar to the first surface 131a of the first light-transmissive member 131A, the second surface 132a also has a rectangular shape that is longer in the X direction compared to the Y direction in the figure.

[0019] The second surface 132a of the second light-transmissive member 132A has a convex shape that rises on the side opposite to the second light-emitting element 122, and includes a second apex 132t that is located at a position farthest from the second light-emitting element 122. In the example shown in Fig. 3, the second surface 132a of the second light-transmissive member 132A is also a curved surface whose entirety is exposed from the light-reflective member 140A.

[0020] For the reasons described above, it is preferable that the position of the second apex 132 in the first cross section (ZX cross section) also coincides with the position of the center of the light emitting element 122. Moreover, it is more preferable that the first surface 131a in the first cross section (ZX cross section) is symmetrical with respect to the first apex 131t.

[0021] The height H1 of the first apex 131t on the first surface 131a and the height H2 of the second apex 132t on the second surface 132a are each preferably, for example, 0.01 mm or more and 0.05 mm or less, and more preferably 0.02 mm or more and 0.04 mm or less. The height H1 is defined as the distance in the Z direction between the outer edge of the first surface 131a (the lowest point on each surface) and the highest point of the first apex 131t. The height H2 is defined in a similar manner.

[0022] The light reflective member 140A is disposed on the substrate 110 so as to surround the first light emitting element 121 and the second light emitting element 122, and covers a part of the upper surface 110a of the substrate 110. As shown in FIG. 3, the light reflective member 140A contacts the side surface 131c of the first light transmissive member 131A and the side surface 132c of the second light transmissive member 132A. The side surface 131c of the first light transmissive member 131A is a surface located between the first surface 131a and the lower surface 131b located on the opposite side to the first surface 131a, among the surfaces that define the shape of the first light transmissive member 131A. Similarly, the side surface 132c of the second light transmissive member 132A is a surface located between the second surface 132a and the lower surface 132b located on the opposite side to the second surface 132a, among the surfaces that define the shape of the second light transmissive member 132A.

[0023] 3, the light reflecting member 140A is in contact with a portion of the side surface 121c of the first light emitting element 121 that is not covered by the first bonding member 151 and a portion of the side surface 122c of the second light emitting element 122 that is not covered by the second bonding member 152. The light reflecting member 140A is also in contact with an outer surface 151c of the first bonding member 151 and an outer surface 152c of the second bonding member 152.

[0024] The light reflective member 140A has a first convex portion 141. The first convex portion 141 is located between the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A in the first direction (the X direction in the figure).

[0025] The first convex portion 141 includes at least a portion located above the first apex 131t of the first surface 131a and the second apex 132t of the second surface 132a in the first cross section. In the example shown in FIG. 3, the first convex portion 141 has a substantially flat first apex 141t, and a first side surface 141c and a second side surface 141d each substantially perpendicular to the first apex 141t. Of these surfaces, the first apex 141t is located above the first apex 131t of the first light-transmissive member 131A and the second apex 132t of the second light-transmissive member 132A in the Z direction in the figure. The shape of the first apex 141t is not limited to a flat shape, and may be a curved shape, etc.

[0026] Fig. 4 and Fig. 5 are schematic cross-sections taken along planes P4 and P5 shown in Fig. 2, i.e., cross-sections taken when the light emitting device is cut parallel to the YZ plane in the drawings at a position passing through the first light emitting element. Of Fig. 4 and Fig. 5, Fig. 5 shows a cross-section taken when the light emitting device 100A is cut at a position including the first apex 131t of the first surface 131a of the first light-transmissive member 131A.

[0027] 4 and 5, the upper surface of the light reflective member 140A includes a pair of first regions 41 located outside the first surface 131a of the first light-transmissive member 131A in the Y direction of the figures. Each of the first regions 41 is aligned with the first surface 131a in the Y direction of the figures.

[0028] 4 and 5, in a typical embodiment of the present disclosure, the shape of the first surface 131a in a cross section (second cross section) perpendicular to the first direction in which the light emitting elements are arranged is flat. Here, the first apex 131t of the first surface 131a is linear and extends in the Y direction in the figures.

[0029] Fig. 6 is a schematic cross-section of the light emitting device 100A taken along a line including the second apex 132t of the upper surface of the second light-transmissive member 132A and parallel to the YZ plane of the figure. As in the example described with reference to Figs. 4 and 5, the upper surface of the light reflective member 140A includes a pair of second regions 42 located outside the second surface 132a of the second light-transmissive member 132A in the Y direction of the figure. As shown in Fig. 6, each of the second regions 42 is aligned with the second surface 132a in the Y direction of the figure.

[0030] As shown in Fig. 6, in a typical embodiment of the present disclosure, the shape of the second surface 132a in the second cross section (here, the YZ cross section in the figure) is also flat. In the example shown in Fig. 6, the second regions 42 located on the left and right of the second surface 132a are also flat.

[0031] In the configuration illustrated in Fig. 6, the second apex 132t of the second surface 132a is linear extending in the Y direction in the figure, similar to the first apex 131t of the first surface 131a. Note that a cross section that appears when the light emitting device 100A is cut parallel to the YZ plane in the figure at a position that passes through the second light emitting element 122 and does not include the second apex 132t of the second surface 132a may be substantially the same as the cross section shown in Fig. 4. Therefore, illustration and description of such a cross section of the light emitting device 100A will be omitted here.

[0032] The first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A exposed from the upper surface of the light-reflective member 140A constitute the light-emitting surface (light-emitting surface) of the light-emitting device 100A. In the above-mentioned example, the first surface 131a located above the first light-emitting element 121 and the second surface 132a located above the second light-emitting element 122 each have a convex curved surface on the opposite side to the light-emitting element (the first light-emitting element 121 or the second light-emitting element 122). In addition, the light-reflective member 140A includes a portion located above the first apex 131t of the first surface 131a and the second apex 132t of the second surface 132a in the first cross section. Therefore, as described later, even when the light-emitting device 100A is disposed facing the light guide plate, direct contact between the first surface 131a and the second surface 132a as the light-emitting surface and the light guide plate can be avoided.

[0033] As will be described in detail later, first surface 131a and second surface 132a serving as light-emitting surfaces have convex curved surfaces, which can expand the spread of light in a plane parallel to the first cross section. According to an embodiment of the present disclosure, light-reflective member 140A has first convex portion 141 including a portion located above first apex 131t of first surface 131a and second apex 132t of second surface 132a. This makes it possible to efficiently cause light emitted from first surface 131a and second surface 132a to enter light guide plate 200 by utilizing the reflection of light by first convex portion 141.

[0034] Fig. 7 shows a schematic diagram of an example of a backlight having a light emitting device 100A. The backlight 300 shown in Fig. 7 includes the above-mentioned light emitting device 100A and a light guide plate 200 having an upper surface 200a and a plurality of side surfaces 200c. Fig. 7 shows both the appearance of the backlight 300 when viewed perpendicularly from the upper surface 200a side of the light guide plate 200 and the appearance of the backlight 300 when viewed from the side, in a single figure.

[0035] 7, the light emitting device 100A is mounted on the wiring substrate 400 together with the light guide plate 200 such that the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A face one of the side surfaces 200c of the light guide plate 200. At this time, the first top surface 141t of the first convex portion 141 of the light reflective member 140A can be brought into contact with the side surface 200c of the light guide plate 200.

[0036] A part or the whole of the first top surface 141t of the first convex portion 141 contacts the side surface 200c of the light guide plate 200, thereby avoiding direct contact between the first surface 131a and the second surface 132a serving as light exit surfaces and the light guide plate 200. This can prevent damage to the first light-transmissive member 131A or the second light-transmissive member 132A due to contact with the light guide plate 200, etc.

[0037] In this example, first top surface 141t of first convex portion 141 has a generally flat shape. Since first convex portion 141 of light reflective member 140A has first top surface 141t of such a shape, it is possible to reduce the concentration of stress on first convex portion 141 when it is brought into contact with light guide plate 200 or the like, compared to a case in which first convex portion 141 contacts an external member such as light guide plate 200 at, for example, one point. This makes it possible to prevent damage to first convex portion 141 caused by contact with an external member such as light guide plate 200.

[0038] In this manner, by providing light reflective member 140A with a portion (e.g., first convex portion 141) that protrudes toward the opposite side of first light emitting element 121 and second light emitting element 122 compared to first surface 131a and second surface 132a, it is possible to prevent first surface 131a and second surface 132a from contacting light guide plate 200. Damage to the light transmissive member caused by contact with the light guide plate, etc., is avoided, and as a result, the reliability of the light emitting device is improved.

[0039] However, if the distance between the side surface 200c of the light guide plate 200 and the first surface 131a and the second surface 132a is extremely large, the amount of light incident from the light emitting device 100A to the light guide plate 200 may decrease. For this reason, the distance between the side surface 200c of the light guide plate 200 and the first apex 131t of the first surface 131a and the second apex 132t of the second surface 132a is preferably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 50 μm or less. In other words, it is advantageous for the height of the first protrusion 141 to be in the range of 10 μm or more and 100 μm or less. Here, the height of the first convex portion 141 can be defined as the distance H1 (see Figures 5 and 6) along the Z direction from the first apex 131t of the first surface 131a or the second apex 132t of the second surface 132a to the first top surface 141t of the first convex portion 141.

[0040] In the light emitting device 100A, the light emitted from the first light emitting element 121 and incident on the first light-transmissive member 131A is extracted to the outside of the light emitting device 100A from the first surface 131a of the first light-transmissive member 131A. Similarly, the light emitted from the second light emitting element 122 and incident on the second light-transmissive member 132A is extracted to the outside of the light emitting device 100A from the second surface 132a of the second light-transmissive member 132A. The light emitted from the first surface 131a and the light emitted from the second surface 132a each spread as it travels toward the light guide plate 200. By making the shape of the light emitting surface (here, each of the first surface 131a and the second surface 132a) of the light emitting device 100A convex with respect to the side surface 200c of the light guide plate 200, the spread of the light can be further expanded compared to the case where the light emitting surface is flat.

[0041] 7, the first convex portion 141 of the light reflective member 140A has a first side surface 141c and a second side surface 141d that are substantially perpendicular to the first top surface 141t. The first side surface 141c is located between the first top surface 141t and the first surface 131a of the first light-transmissive member 131A, and the second side surface 141d is located between the first top surface 141t and the second surface 132a of the second light-transmissive member 132A.

[0042] Of the light emitted from the light emission surface of the light emitting device 100A, a component whose traveling direction has a large angle with respect to the Z direction in the figure is incident on the first convex portion 141 before reaching the side surface 200c of the light guide plate 200, as shown typically by a solid arrow Ry in Fig. 7. For example, light emitted from the first surface 131a of the first light-transmissive member 131A toward the second light-transmissive member 132A side at a large angle with respect to the Z direction in the figure is incident on the first side surface 141c of the first convex portion 141, as shown typically in an enlarged view in Fig. 7. Light emitted from the second surface 132a of the second light-transmissive member 132A toward the first light-transmissive member 131A side at a large angle with respect to the Z direction in the figure is incident on the second side surface 141d of the first convex portion 141.

[0043] The light incident on the first side surface 141c of the first convex portion 141 is reflected by the first side surface 141c and enters the side surface 200c of the light guide plate 200. Similarly, the light incident on the second side surface 141d of the first convex portion 141 is reflected by the second side surface 141d and enters the side surface 200c of the light guide plate 200. In this manner, in this embodiment, the light emitting surface is shaped to be convex toward the conductor plate 200, thereby expanding the spread of the light, and the light beam emitted at a large angle with respect to the optical axis of the light emitting element is reflected by the portion of the light reflective member 140A protruding toward the light guide plate 200. By utilizing the reflection of the portion of the light reflective member 140A protruding toward the light guide plate, the light is concentrated forward, and it becomes possible to allow the entrance of the light beam at a larger angle with respect to the optical axis of the light emitting element into the light guide plate 200. Therefore, according to the embodiment of the present disclosure, the light emitted at a larger angle with respect to the optical axis of the light emitting element can be more effectively utilized.

[0044] On the other hand, when paying attention to the short-side direction (Y direction in the figure) of the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A, in a typical embodiment of the present disclosure, the shapes of the first surface 131a and the second surface 132a in a cross section perpendicular to the first direction are flat, as described with reference to Figs. 4 to 6. That is, unlike the long-side direction of the first surface 131a and the second surface 132a, the spread of light centered on the optical axis of the light-emitting element in the YZ plane perpendicular to the first direction is relatively small. Therefore, even if the first region 41 and the second region 42 on the upper surface of the light-reflective member 140A are surfaces aligned with the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A, respectively, it is possible to avoid the occurrence of excessive leakage of light in the short-side direction of the first surface 131a and the second surface 132a.

[0045] According to the embodiment of the present disclosure, it is possible for light emitted from first surface 131a or second surface 132a to be more efficiently incident on light guide plate 200. For example, even in a case where first surface 131a and second surface 132a are separated from light guide plate 200 by about 100 μm, it is possible to avoid a reduction in the light incident on light guide plate 200 from light emitting device 100A.

[0046] 7, the light reflective member 140A may further have a second convex portion 142 and a third convex portion 143 that protrude in the +Z direction from the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A. The second convex portion 142 and the third convex portion 143 are provided at both ends of the light reflective member 140A in the X direction in the figure. The second convex portion 142 and the third convex portion 143 are not essential for the light emitting device 100A.

[0047] Referring again to FIG. 3, the second convex portion 142 of the light reflective member 140A is located on the opposite side to the first convex portion 141 with respect to the position of the first surface 131a of the first light-transmitting member 131A in the X direction of the figure. The second convex portion 142 includes a portion located above both ends of the first surface 131a in the X direction of the figure. In the configuration illustrated in FIG. 3, the second convex portion 142 has a second top surface 142t that is in the same plane as the first top surface 141t of the first convex portion 141, and a third side surface 142c that is approximately perpendicular to the second top surface 142t. The second top surface 142t is a flat surface like the first top surface 141t of the first convex portion 141. A part of the third side surface 142c of the second convex portion 142 faces the first side surface 141c of the first convex portion 141 in the X direction of the figure.

[0048] On the other hand, the third convex portion 143 is located on the opposite side to the first convex portion 141 with respect to the position of the second surface 132a of the second light-transmitting member 132A in the X direction in the figure. The third convex portion 143 includes a portion located above both ends of the second surface 132a in the X direction in the figure. In the example shown in FIG. 3, the third convex portion 143 has a third top surface 143t and a fourth side surface 143d that is approximately perpendicular to the third top surface 143t. Here, like the first top surface 141t of the first convex portion 141 and the second top surface 142t of the second convex portion 142, the third top surface 143t is also a flat surface.

[0049] 3, when the second convex portion 142 and the third convex portion 143 are disposed at both ends in the longitudinal direction of the light emitting device 100A, it is possible to more reliably prevent the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A from directly contacting the light guide plate 200. Furthermore, by making the second top surface 142t and the third top surface 143t flat, it is possible to prevent stress from concentrating on the second convex portion 142 and the third convex portion 143 when the second convex portion 142 and the third convex portion 143 are brought into contact with the light guide plate 200 or the like, and it is expected to be effective in avoiding damage to the second convex portion 142 and / or the third convex portion 143.

[0050] By appropriately adjusting the heights of the second convex portion 142 and the third convex portion 143, it becomes easy to mount the light emitting device 100A on the wiring board 400 so that the light emitting device 100A faces parallel to the side surface 200c of the light guide plate 200 (see FIG. 7). The heights of the second convex portion 142 and the third convex portion 143, like the height of the first convex portion 141, can be defined as the distance along the Z direction from the first apex 131t of the first surface 131a or the second apex 132t of the second surface 132a to the second apex 142t or the third apex 143t in the ZX cross section.

[0051] By disposing the second convex portion 142 and the third convex portion 143 at both ends in the longitudinal direction of the light emitting device 100A, it becomes possible to utilize reflection at the third side surface 142c of the second convex portion 142 and reflection at the fourth side surface 143d of the third convex portion 143. In other words, it becomes possible to reduce leakage of light to the outside of the light emitting device 100A in the longitudinal direction of the light emitting device 100A, and to advantageously allow light that spreads widely within the ZX plane to enter the light guide plate 200.

[0052] In the above examples, the shape of each of the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A in the first cross section is an arc shape obtained by extracting a part of a perfect circle. However, the shape of each of the first surface 131a and the second surface 132a in the first cross section is not limited to this example. The shape of the first surface 131a and the second surface 132a in the cross section may be a shape obtained by extracting a part of an ellipse or an oval, a shape including projections and recesses, a shape including a linear portion, or a shape that is a combination of these.

[0053] Second embodiment 8 and 9 are schematic diagrams illustrating the appearance of a light emitting device according to a second embodiment of the present disclosure. Fig. 9 corresponds to a top view of the light emitting device 100B shown in Fig. 8 when the light emitting device 100B is viewed in the Z direction in the figure.

[0054] 8 and 9 has a light reflective member 140B instead of the light reflective member 140A, and has a first light transmissive member 131B and a second light transmissive member 132B instead of the first light transmissive member 131A and the second light transmissive member 132A, respectively. While the first surface 131a of the first light transmissive member 131A and the second surface 132a of the second light transmissive member 132A of the light emitting device 100A are curved in cross-sectional view, in this embodiment, the first surface 131a of the first light transmissive member 131B and the second surface 132a of the second light transmissive member 132B have a shape formed by combining flat surfaces.

[0055] As shown in FIG. 9, the first surface 131a of the first light-transmissive member 131B includes a first inclined surface 31s and a second inclined surface 31t, each of which is flat. The first inclined surface 31s is connected to the second inclined surface 31t at the center of the first surface 131a, and a linear first apex 131t is formed at the boundary between the first inclined surface 31s and the second inclined surface 31t. Similarly, the second surface 132a of the second light-transmissive member 132B includes a third inclined surface 32s and a fourth inclined surface 32t, each of which is flat. A linear second apex 132t is formed at the center of the second surface 132a where the third inclined surface 32s is connected to the fourth inclined surface 32t.

[0056] In this embodiment, the first region 41 of the upper surface of the light reflective member 140B also includes a plurality of inclined surfaces, in correspondence with the first surface 131a including the first inclined surface 31s and the second inclined surface 31t. That is, the first region 41 includes a pair of first inclined regions 41s each aligned with the first inclined surface 31s of the first surface 131a, and a pair of second inclined regions 41t each aligned with the second inclined surface 31t of the first surface 131a. As shown in FIG. 9, the first inclined surface 31s of the first light-transmitting member 131B is located between the first inclined regions 41s of the light reflective member 140B, and the second inclined surface 31t is located between the second inclined regions 41t.

[0057] In the upper surface of the light reflective member 140B, the second region 42 includes a pair of third inclined regions 42s each aligned with the third inclined surface 32s of the second surface 132a, and a pair of fourth inclined regions 42t each aligned with the fourth inclined surface 32t of the second surface 132a. The third inclined surface 32s of the second light-transmissive member 132B is located between the third inclined regions 42s of the light reflective member 140B, and the fourth inclined surface 32t is located between the fourth inclined regions 42t.

[0058] FIG. 10 is a schematic diagram of a cross section of the light emitting device shown in FIG. 8 and FIG. 9. As shown in FIG. 10, the center of the first surface 131a of the first light-transmissive member 131B is higher in the +Z direction than both ends in the X direction of the figure. As described with reference to FIG. 8 and FIG. 9, the first surface 131a includes a first inclined surface 31s and a second inclined surface 31t. The first inclined surface 31s is spaced apart from the upper surface 121a of the first light emitting element 121 from one end (for example, the side close to the second convex portion 142 of the light reflective member 140B) in the X direction of the first surface 131a toward the center, and the second inclined surface 31t is spaced apart from the upper surface 121a of the first light emitting element 121 toward the center from the other end. In this example, the shape of the first surface 131a in the ZX cross section is generally V-shaped.

[0059] In the example shown in FIG. 10, the shape of the second surface 132a of the second light-transmissive member 132B in the ZX cross section is also approximately V-shaped. As described above, here, the second surface 132a includes the third inclined surface 32s and the fourth inclined surface 32t. As shown in FIG. 10, the third inclined surface 32s is spaced apart from the upper surface 122a of the second light-emitting element 122 from one end (for example, the side close to the first convex portion 141 of the light-reflective member 140B) of the second surface 132a in the X direction toward the center. The fourth inclined surface 32t is spaced apart from the upper surface 122a of the second light-emitting element 122 from the other end of the second surface 132a toward the center.

[0060] The height H1 of the first apex 131t and the height H2 of the second apex 132t are each, for example, preferably 0.01 mm or more and 0.05 mm or less, and more preferably 0.02 mm or more and 0.04 mm or less. The height H1 is defined as the distance in the Z direction between the outer edge of the first surface 131a (the lowest point on each surface) and the highest point of the first apex 131t. The height H2 is defined in a similar manner.

[0061] According to the study by the present inventors, even when the shape of the first surface 131a in the ZX cross section is V-shaped, the spread of light in the ZX plane can be expanded in the same way as when the shape of the first surface 131a is curved. That is, even when the shape of the first surface 131a in the ZX cross section is V-shaped, more light can be made to enter the light guide plate by utilizing the reflection at the first side surface 141c of the first convex portion 141 or the third side surface 142c of the second convex portion 142. Similarly, even when the shape of the second surface 132a in the ZX cross section is V-shaped, the spread of light in the ZX plane can be expanded, and more light can be made to enter the light guide plate by utilizing the reflection at the second side surface 141d of the first convex portion 141 or the fourth side surface 143d of the third convex portion 143. That is, even according to this embodiment, it is possible to efficiently make light enter the light guide plate when applied to a backlight.

[0062] When the light emitting device according to this embodiment is cut along a plane perpendicular to the direction in which the two light emitting elements are arranged (i.e., the second cross section), the shapes of the first surface 131a and the second surface 132a are both flat, similar to the example described with reference to Figures 4 to 6. By making the cross-sectional shapes of the first surface 131a and the second surface 132a in the YZ plane linear, the spread of light in the YZ plane can be suppressed compared to the ZX plane. This makes it possible to efficiently make the light emitted from the first light emitting element 121 and the second light emitting element 122 enter the light guide plate.

[0063] (Other variations) Next, various modified examples of the light emitting device will be described. Here, the light emitting device 100A shown in Fig. 3 will be described as an example, but it goes without saying that the same modifications can be applied to the light emitting device 100B shown in Fig. 10. In addition, two or more of the modifications described below may be combined.

[0064] Fig. 11 shows an example of a light emitting device further having a first wavelength conversion member and a second wavelength conversion member. Compared to the light emitting device 100A shown in Fig. 3, the light emitting device 100C shown in Fig. 11 further has a first wavelength conversion member 161 located between the first light transmissive member 131A and the first light emitting element 121, and a second wavelength conversion member 162 located between the second light transmissive member 132A and the second light emitting element 122. In the configuration shown in Fig. 11, the light reflective member 140A is also in contact with a side surface 161c of the first wavelength conversion member 161 and a side surface 162c of the second wavelength conversion member 162.

[0065] First wavelength conversion member 161 and second wavelength conversion member 162 contain a base material and phosphor particles or the like, and the phosphor in first wavelength conversion member 161 absorbs at least a portion of the light emitted from first light emitting element 121 and emits light with a wavelength different from the wavelength of the light from first light emitting element 121. Similarly, the phosphor in second wavelength conversion member 162 absorbs at least a portion of the light emitted from second light emitting element 122 and emits light with a wavelength different from the wavelength of the light from second light emitting element 122.

[0066] A typical example of the first light emitting element 121 and the second light emitting element 122 is an LED that emits blue light. In this case, the first wavelength conversion member 161 and the second wavelength conversion member 162 can respectively convert the wavelength of a part of the incident blue light to emit, for example, yellow light, or red light and green light. With this configuration, white light is obtained by mixing the blue light that has passed through the translucent member with the yellow light emitted from the phosphor contained in the translucent member, or by mixing the blue light that has passed through the translucent member with the red light and green light.

[0067] The first light-transmissive member 131A and the second light-transmissive member 132A have the above-mentioned shape, and the thickness is large near the first top 131t and the second top 132t. Therefore, when the first light-transmissive member 131A and the second light-transmissive member 132A contain a phosphor, the amount of wavelength conversion of the light emitted from the first light-emitting element 121 and the second light-emitting element 122 varies depending on the position where the light passes through the first light-transmissive member 131A and the second light-transmissive member 132A, and color unevenness is likely to occur. In contrast, according to the light-emitting device shown in FIG. 11, the first light-transmissive member 131A and the second light-transmissive member 132A do not contain a phosphor, and the thicknesses of the first wavelength conversion member 161 and the second wavelength conversion member 162 can be made constant, so that color unevenness in the light emitted from the light-emitting device can be reduced.

[0068] FIG. 12 shows another modified example of the light emitting device according to the embodiment of the present disclosure. The configuration shown in FIG. 12 is an example in which a single light-transmitting member is disposed above the first light emitting element and the second light emitting element. Compared to the light emitting device 100A shown in FIG. 3, the light emitting device 100D shown in FIG. 12 has a light-transmitting member 130 that collectively covers the upper surface 121a of the first light emitting element 121 and the upper surface 122a of the second light emitting element 122, instead of the first light-transmitting member 131A and the second light-transmitting member 132A. Moreover, the light emitting device 100D has a light-reflective member 140D instead of the light-reflective member 140A.

[0069] In each of the above-mentioned examples, the light emitting device has the first light emitting element 121 and the second light emitting element 122, and accordingly, the first light transmissive member and the second light emitting member are disposed above the first light emitting element 121 and the second light emitting element 122, respectively. However, without being limited to these examples, as illustrated in FIG. 12, a single light transmissive member 130 may be provided in the light emitting device 100D so as to cover both the upper surface 121a of the first light emitting element 121 and the upper surface 122a of the second light emitting element 122.

[0070] 12, a first wavelength conversion member 161 and a second wavelength conversion member 162 may be disposed above the first light emitting element 121 and the second light emitting element 122, respectively. In this example, the light reflective member 140D is in contact with a side surface 161c of the first wavelength conversion member 161 and a side surface 162c of the second wavelength conversion member 162.

[0071] 12, a plurality of portions of light-transmitting member 130 are exposed from light-reflective member 140D. Of these portions, the portion exposed from light-reflective member 140D above first light-emitting element 121 is first surface 131a, and the portion exposed from light-reflective member 140D above second light-emitting element 122 is second surface 132a. In this example, each of first surface 131a and second surface 132a is a convex curved surface.

[0072] By disposing the light-transmitting member 130 above both the first light-emitting element 121 and the second light-emitting element 122, the light from the first light-emitting element 121 and the light from the second light-emitting element 122 are mixed inside the light-transmitting member 130. This makes it possible to reduce the difference in the intensity of the light extracted from the first surface 131a and the second surface 132a.

[0073] Fig. 13 shows an example in which a single light-transmitting member and a single wavelength conversion member are disposed above the first light-emitting element and the second light-emitting element. Compared to the light-emitting device 100D shown in Fig. 12, the light-emitting device 100E shown in Fig. 13 has a wavelength conversion member 163 that collectively covers the upper surface 121a of the first light-emitting element 121 and the upper surface 122a of the second light-emitting element 122, instead of the first wavelength conversion member 161 and the second wavelength conversion member 162.

[0074] By disposing the light-transmitting member 130 and the wavelength conversion member 163 above both the first light-emitting element 121 and the second light-emitting element 122, the light from the first light-emitting element 121 and the light from the second light-emitting element 122 can be mixed inside at least one of the light-transmitting member 130 and the wavelength conversion member 163. This makes it possible to reduce the difference in the intensity of the light extracted from the first surface 131a and the second surface 132a of the light-transmitting member 130.

[0075] Fig. 14 shows yet another modified example of the light emitting device. In each of the above-mentioned examples, the light emitting device has a substrate 110 on which a first light emitting element 121 and a second light emitting element 122 are mounted. In contrast, a light emitting device 100F shown in Fig. 14 has a wiring layer 160 located below the first light emitting element 121 and the second light emitting element 122 instead of the substrate 110.

[0076] In the example shown in Fig. 14, lower surfaces 24b of electrodes 24 of first light-emitting element 121 and second light-emitting element 122 are exposed from lower surface 140b of light-reflective member 140A. Wiring layer 160 is formed on lower surface 140b of light-reflective member 140A and is electrically connected to electrodes 24. Fig. 14 shows an example in which first light-emitting element 121 and second light-emitting element 122 are electrically connected in series by wiring layer 160. As in this example, substrate 110 may be omitted from the light-emitting device.

[0077] The cross-sectional shape of the light reflective member (light reflective member 140A, 140B, or 140D) is not limited to the shape shown in the drawings. For example, at least one of the first side surface 141c and the second side surface 141d of the first convex portion 141, the third side surface 142c of the second convex portion 142, and the fourth side surface 143d of the third convex portion 143 may have a shape inclined from the Z direction in the first cross section. That is, the first side surface 141c and the third side surface 142c may be inclined with respect to a plane perpendicular to the upper surface 121a of the first light emitting element 121 so as to widen upward, and the second side surface 141d and the fourth side surface 143d may be inclined with respect to a plane perpendicular to the upper surface 122a of the second light emitting element 122 so as to widen upward. Furthermore, as shown in FIG. 13, the light reflective member (light reflective member 140A, 140B or 140D) may cover a portion of the upper surface of the light transmissive member (first light transmissive member 131A, 131B and second light transmissive member 132A, 132B or light transmissive member 130).

[0078] In the first embodiment, the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A are each composed of one curved surface, and in the second embodiment, they are composed of multiple flat surfaces. The shapes of the first surface 131a and the second surface 132a are not limited to these examples, and may be composed of multiple curved surfaces or multiple flat surfaces, or may further be composed of a combination of curved surfaces and flat surfaces.

[0079] In the first and second embodiments, the first apex 131t of the first surface 131a and the second apex 132t of the second surface 132a are vertices in the first cross section. However, the first apex 131t and the second apex 132t are not limited to points, and may be apexes having a predetermined width in the YX plane in order to increase the emitted light parallel to the Z direction.

[0080] Hereinafter, the light emitting device 100A shown in FIGS. 1 to 6 will be mainly taken as an example to describe the details of each member in the light emitting device.

[0081] [Substrate 110] The substrate 110 is a support member on which the first light emitting element 121 and the second light emitting element 122 are mounted. In response to the first light emitting element 121 and the second light emitting element 122 being mounted along the first direction (the X direction in the figure), the upper surface 110a of the substrate 110 typically has a rectangular shape that is longer in the X direction compared to the Y direction in the figure. For example, as can be seen from Figures 1 and 2, the substrate 110 is generally rectangular parallelepiped in shape as a whole.

[0082] 3, the substrate 110 includes a base material 10 having an upper surface 110a and a lower surface 110b located opposite the upper surface 110a, a first wiring 11, a second wiring 12, and a conductive member 15 disposed inside the base material 10. The upper surface of the base material 10 is included in the upper surface 110a of the substrate 110, and the lower surface of the substrate 10 is included in the lower surface 110b of the substrate 110. The first wiring 11 and the second wiring 12 are located on the upper surface 110a side and the lower surface 110b side of the substrate 110, respectively. The conductive member 15 penetrates the substrate 10 to electrically connect the first wiring 11 and the second wiring 12 to each other.

[0083] The substrate 10 is a roughly rectangular parallelepiped support member on which the first wiring 11 and the second wiring 12 are arranged. Examples of materials for the substrate 10 include insulators such as resin, ceramics, or glass. The substrate 10 may be formed from a composite material such as fiber-reinforced resin, and for example, a glass epoxy substrate may be applied to the substrate 10. The base material for the substrate 10 may be epoxy, bismaleimide triazine (BT), polyimide, or the like. As ceramics, aluminum oxide, aluminum nitride, zirconium oxide, zirconium nitride, titanium oxide, titanium nitride, or a mixture of one or more of these may be applied. Of these ceramics, it is advantageous to use a material having a linear expansion coefficient close to that of the light emitting element as the material for the substrate 10.

[0084] From the viewpoint of the strength of the substrate 110, it is beneficial for the thickness of the base material 10 in the Z direction to be 0.05 mm or more, and more preferably 0.2 mm or more. It is advantageous for the thickness of the base material 10 in the Z direction to be 0.6 mm or less in order to make the light emitting device thinner. The thickness of the base material 10 in the Z direction is preferably 0.5 mm or less, and more preferably 0.4 mm or less.

[0085] 2 and 4, the substrate 10 may have one or more recesses 10R each opening to the lower surface and bottom surface 10m of the substrate 10. Here, the bottom surface 10m of the substrate 10 is a surface located between the upper surface and lower surface of the substrate 10, and is a surface that faces the upper surface of a wiring board when applied to a backlight.

[0086] The substrate 110 further has a third wiring 13 covering the inner wall of the recess 10R. As shown in Fig. 4, the third wiring 13 is disposed on the surface of the base material 10 in continuity with the second wiring 12 on the lower surface 110b of the substrate 110, and is thereby electrically connected to the second wiring 12. When applied to a backlight, as shown in Fig. 7, the light emitting device 100A can be mounted on a wiring substrate by disposing solder 90 so as to be located within these recesses 10R.

[0087] The first wiring 11, the second wiring 12, and the third wiring 13 may be made of copper, iron, nickel, tungsten, chromium, aluminum, silver, platinum, gold, titanium, palladium, rhodium, or an alloy containing one or more of these. From the viewpoint of heat dissipation, it is advantageous to use copper or a copper alloy as the material of these wirings. The first wiring 11, the second wiring 12, and the third wiring 13 may be formed on the substrate 10 in the form of a single layer film, or may be formed on the substrate 10 in the form of a laminated film. If the outermost surface of these wirings is formed of silver, platinum, aluminum, rhodium, or gold, or an alloy containing one or more of these, it is beneficial because high light reflectivity and good wettability with solder, etc. can be obtained.

[0088] The conductive member 15 may be made of the same material as the first wiring 11, the second wiring 12, or the third wiring 13. The conductive member 15 may occupy the entire inside of the through hole formed in the substrate 10, or may be a part of the inside of the through hole, for example, a conductive film disposed on the surface of the through hole. Furthermore, the region surrounded by the conductive film may be filled with an insulating material such as an epoxy resin.

[0089] Fig. 15 shows an exemplary appearance of the light emitting device 100A when viewed from the lower surface 110b side of the substrate 110, and Fig. 16 shows an exemplary appearance of the light emitting device 100A when viewed from the bottom surface 10m side of the base material 10. In the example shown in Fig. 15, the openings of the recesses 10R each have a semicircular shape. These recesses 10R may be disposed symmetrically with respect to the center of the base material 10 in the X direction of the figure. As shown typically in Fig. 15, the conductive member 15 is formed in a position that does not overlap the recesses 10R.

[0090] 15, the substrate 110 further includes one or more insulating layers 18. The insulating layers 18 are formed from a thermosetting resin or a thermoplastic resin, and cover a portion of each of the second wirings 12 located on the lower surface of the base material 10. By disposing such an insulating layer 18 on the lower surface 110b side of the substrate 110, an effect of preventing short circuits between the second wirings 12 can be obtained.

[0091] Referring to Fig. 16, attention will be paid to the shape of the opening of each recess 10R at the bottom surface 10m of the substrate 10. As shown in Fig. 16, the recess 10R may have a shape in which the depth in the Z direction is greater at the center compared to both ends in the X direction of the figure. Note that, as shown in Fig. 4, the recess 10R may have a shape in which the depth in the Z direction of the figure increases toward the bottom surface 10m.

[0092] [First light-emitting element 121 and second light-emitting element 122] The first light emitting element 121 and the second light emitting element 122 are semiconductor elements that emit light when supplied with current. The first light emitting element 121 and the second light emitting element 122 may have generally the same basic structure. In the following, the structure of the first light emitting element 121 will be mainly described, and a description of the second light emitting element 122 will be omitted.

[0093] As described with reference to FIG. 3, the first light emitting element 121 has an electrode 24 located on the lower surface opposite to the upper surface 121a. The electrode 24 includes a pair of a positive electrode and a negative electrode. Examples of materials for the electrode 24 include gold, silver, tin, platinum, rhodium, titanium, aluminum, tungsten, palladium, nickel, or an alloy containing one or more of these. The first light emitting element 121 is mounted on the substrate 110 by connecting and fixing the electrode 24 to the first wiring 11 of the substrate 110 with a bonding member such as solder.

[0094] The first light emitting element 121 further has a semiconductor laminate structure including an n-type semiconductor layer, a p-type semiconductor layer, and an active layer sandwiched therebetween. The semiconductor laminate structure may be formed on a light-transmitting substrate such as sapphire or gallium nitride. When the first light emitting element 121 includes a light-transmitting substrate as a part thereof, the upper surface of the light-transmitting substrate constitutes the upper surface 121a of the first light emitting element 121. The above-mentioned electrode 24 is provided on the surface of the semiconductor laminate structure opposite to the light-transmitting substrate. The electrode 24 has an electrical connection with the semiconductor laminate structure and has a function of supplying a predetermined current to the semiconductor laminate structure.

[0095] The semiconductor laminate structure is made up of nitride semiconductors (In x Al y Ga 1-x-y N, 0≦x, 0≦y, x+y≦1). The first light emitting element 121 and the second light emitting element 122 may have different emission peak wavelengths. For example, a semiconductor laminate structure that mainly emits blue light may be applied to the first light emitting element 121, and a semiconductor laminate structure that mainly emits green light may be applied to the second light emitting element 122.

[0096] [First translucent member 131A, second translucent member 132A] The first light-transmissive member 131A and the second light-transmissive member 132A are generally plate-shaped members disposed above the first light-emitting element 121 and the second light-emitting element 122, respectively. The first light-transmissive member 131A and the second light-transmissive member 132A function as protective layers for the first light-emitting element 121 and the second light-emitting element 122.

[0097] The first light-transmissive member 131A and the second light-transmissive member 132A are formed of a resin material whose base material is, for example, a silicone resin, and have light-transmissivity. In this specification, the term "light-transmissive" is interpreted to include the ability to diffuse incident light, and is not limited to being "transparent."

[0098] The first light-transmissive member 131A typically has a transmittance of 60% or more for light having the emission peak wavelength of the first light-emitting element 121. The same can be said for the second light-transmissive member 132A. From the viewpoint of effectively utilizing light, it is beneficial for the transmittance of the light-transmissive members (first light-transmissive member 131A, second light-transmissive member 132A) at the emission peak wavelength of the light-emitting element to be 70% or more, and more beneficial for it to be 80% or more.

[0099] The base material of the first light-transmitting member 131A and the second light-transmitting member 132A may be silicone resin, or may be, for example, silicone-modified resin, epoxy resin, phenol resin, polycarbonate resin, acrylic resin, polymethylpentene resin, polynorbornene resin, or a material containing two or more of these. Glass may also be selected as the material of the first light-transmitting member 131A and the second light-transmitting member 132A.

[0100] The first light-transmitting member 131A and the second light-transmitting member 132A may be given a light diffusion function by dispersing a light diffusion material having a refractive index different from that of the base material in the base material. As the light diffusion material, for example, particles of a resin having a refractive index different from that of the base material, or particles of titanium oxide, magnesium oxide, zirconium dioxide, potassium titanate, aluminum oxide, aluminum nitride, boron nitride, mullite, niobium oxide, barium sulfate, silicon oxide, and various rare earth oxides (for example, yttrium oxide and gadolinium oxide) can be used. As the light diffusion material dispersed in the base material, D 50 By using nanoparticles having a particle size, defined as being 1 nm or more and 100 nm or less, scattering in the light-transmitting member can be increased.

[0101] In an embodiment of the present disclosure, at least a part of the upper surface of the first light-transmissive member 131A and at least a part of the upper surface of the second light-transmissive member 132A are exposed from the light-reflective member 140A and constitute the first surface 131a and the second surface 132a, respectively. That is, the first surface 131a of the first light-transmissive member 131A is a part or all of the upper surface of the first light-transmissive member 131A, and the second surface 132a is a part or all of the upper surface of the second light-transmissive member 132A. The first surface 131a is located above the upper surface 121a of the first light-emitting element 121, and the second surface 132a is located above the upper surface 122a of the second light-emitting element 122. In an embodiment of the present disclosure, the first surface 131a and the second surface 132a are convex in the first cross section.

[0102] [First wavelength conversion member 161, second wavelength conversion member 162] The first wavelength conversion member 161 is a generally plate-shaped member located between the upper surface 121a of the first light-emitting element 121 and the lower surface 131b of the first light-transmissive member 131A. Similarly, the second wavelength conversion member 162 is a generally plate-shaped member located between the upper surface 122a of the second light-emitting element 122 and the lower surface 132b of the second light-transmissive member 132B.

[0103] The first wavelength conversion member 161 and the second wavelength conversion member 162 contain a base material and phosphor particles and the like dispersed in the base material. Examples of the base material of the first wavelength conversion member 161 and the second wavelength conversion member 162 are silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, urea resin, phenol resin, polycarbonate resin, trimethylpentene resin, polynorbornene resin, acrylic resin, urethane resin, or fluororesin, or a resin containing two or more of these. It is also possible to select glass as the base material of the first wavelength conversion member 161 and the second wavelength conversion member 162. From the viewpoint of efficiently introducing light into the first translucent member 131A, it is beneficial for the material of the first wavelength conversion member 161 to have a lower refractive index than the material of the first translucent member 131A. Similarly, it is beneficial for the material of the second wavelength conversion member 162 to have a lower refractive index than the material of the second translucent member 132A. The first wavelength converting member 161 and the second wavelength converting member 162 may be a single layer, or may include a laminated structure of, for example, a plurality of resin layers.

[0104] Known materials can be used for the phosphor dispersed in the first wavelength conversion member 161 and the second wavelength conversion member 162. For example, the phosphor is an yttrium-aluminum-garnet phosphor (e.g., 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 phosphors (e.g., Ca10(PO4)6Cl2:Eu), SAE phosphors (e.g., Sr4Al14O25:Eu), chlorosilicate phosphors (e.g., Ca8MgSi4O16Cl2:Eu), β-sialon phosphors (e.g., (Si,Al)3(O,N)4:Eu), α-sialon phosphors (e.g., Ca(Si,Al) 12 (O,N) 16: Nitride-based phosphors such as (Sr,Ca)AlSiN3:Eu), SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu), or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), fluoride-based phosphors such as KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si,Al)F6:Mn), or MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), phosphors having a perovskite structure (e.g., CsPb(F,Cl,Br,I)3), or quantum dot phosphors (e.g., CdSe, InP, AgInS2, or AgInSe2) can be used.

[0105] The KSAF-based phosphor may have a composition represented by the following formula (I). M2[Si p Al q Mn r F s (I)

[0106] In formula (I), M represents an alkali metal and may contain at least K. Mn may be tetravalent Mn ions. p, q, r, and s may satisfy 0.9 ≦ p + q + r ≦ 1.1, 0 < q ≦ 0.1, 0 < r ≦ 0.2, 5.9 ≦ s ≦ 6.1. Preferably, 0.95 ≦ p + q + r ≦ 1.05 or 0.97 ≦ p + q + r ≦ 1.03, 0 < q ≦ 0.03, 0.002 ≦ q ≦ 0.02 or 0.003 ≦ q ≦ 0.015, 0.005 ≦ r ≦ 0.15, 0.01 ≦ r ≦ 0.12 or 0.015 ≦ r ≦ 0.1, 5.92 ≦ s ≦ 6.05 or 5.95 ≦ s ≦ 6.025. For example, K2[Si 0.946 Al 0.005 Mn 0.049 F 5.995 , K2[Si 0.942 Al 0.008 Mn 0.050 F 5.992 , K2[Si 0.939 Al 0.014 Mn 0.047 F 5.986Such a KSAF phosphor can provide red light emission with high luminance and a narrow half-width of the emission peak wavelength.

[0107] Furthermore, the wavelength conversion member (first wavelength conversion member 161 or second wavelength conversion member 162) may contain one of these phosphors alone, or may contain a combination of two or more of these phosphors.

[0108] For example, according to the configurations shown in Figs. 11 to 14, the wavelength conversion member is interposed between the light emitting element and the light transmissive member, so that the light from the light emitting element can be introduced into the light transmissive member through the wavelength conversion member. This allows the mixed light to be diffused inside the light transmissive member, and for example, white light with reduced luminance unevenness can be extracted to the outside of the light emitting device from the first surface 131a or the second surface 132a. Note that, according to the configuration of the light emitting device 100D shown in Fig. 12, in which the light transmitted through the first wavelength conversion member 161 and the light transmitted through the second wavelength conversion member 162 are introduced into a single light transmissive member 130, the light transmitted through the first wavelength conversion member 161 and the light transmitted through the second wavelength conversion member 162 can be mixed in the light transmissive member 130, which is advantageous in reducing the difference in light intensity extracted from the first surface 131a and the second surface 132a.

[0109] The first wavelength conversion member 161 and the second wavelength conversion member 162 may use the same or different phosphors as the phosphors dispersed in the base material. In addition, by dispersing a light diffusing material having a different refractive index from that of the base material in the material of the first wavelength conversion member 161, the first wavelength conversion member 161 can be given a light diffusing function. Similarly, by dispersing a light diffusing material having a different refractive index from that of the base material in the material of the second wavelength conversion member 162, the second wavelength conversion member 162 can be given a light diffusing function. The light diffusing material can be appropriately selected from the light diffusing materials used in the first light-transmissive member 131A and the second light-transmissive member 132A described above.

[0110] [First joint member 151, second joint member 152] The first bonding member 151 and the second bonding member 152 are not essential to the light emitting device of this embodiment. The first bonding member 151 and the second bonding member 152 are light-transmitting members including at least a portion located on a part of the side surface 121c of the first light emitting element 121 and a portion located on a part of the side surface 122c of the second light emitting element 122. The above-mentioned first wavelength conversion member 161 and the second wavelength conversion member 162 are bonded to the first light emitting element 121 and the second light emitting element 122 by the first bonding member 151 and the second bonding member 152, respectively (see FIG. 11, for example). The details of the second bonding member 152 are almost the same as those of the first bonding member 151, so that the details of the first bonding member 151 will be mainly described below, and a description of the details of the second bonding member 152 will be omitted.

[0111] The first bonding member 151 includes a portion located between the side surface 121c of the first light emitting element 121 and the light reflective member 140A. By disposing the first bonding member 151, a part of the light emitted from the side surface 121c of the first light emitting element 121 can be made to enter the first bonding member 151. The light that has entered the first bonding member 151 is reflected toward the first light-transmissive member 131A at the position of the outer surface 151c of the first bonding member 151, and is emitted toward the outside of the light emitting device 100A via the first light-transmissive member 131A. Therefore, by disposing the first bonding member 151, the light extraction efficiency can be improved.

[0112] A resin material containing a transparent resin as a base material can be used as the material of the first joint member 151. For example, the same material as the base material of the first light-transmissive member 131A can be used as the base material of the first joint member 151. Also, in the first joint member 151, a light diffusing material having a refractive index different from that of the base material can be dispersed, similar to the above-mentioned first light-transmissive member 131A and second light-transmissive member 132A.

[0113] [Light-reflective member 140A] The light reflecting member 140A is disposed on the upper surface 110a of the substrate 110 so as to surround each of the first light emitting element 121 and the second light emitting element 122 in a top view. The light reflecting member 140A covers the structure on the upper surface 110a of the substrate 110 except for the first surface 131a of the first light transmissive member 131A and the second surface 132a of the second light transmissive member 132A. A part of the light reflecting member 140A may be located on a part of the upper surface of the first light transmissive member 131A and / or on a part of the upper surface of the second light transmissive member 132A. In the configuration illustrated in FIG. 12 and FIG. 13, the first convex portion 141 of the light reflecting member 140D is a part of the light reflecting member 140D that is located on the upper surface of the light transmissive member 130 and is sandwiched between the first surface 131a and the second surface 132a.

[0114] The light reflecting member 140A is formed of, for example, a resin material in which a light diffusing material is dispersed. For example, a silicone resin, a modified silicone resin, an epoxy resin, a urea resin, a polycarbonate resin, a phenol resin, an acrylic resin, a urethane resin, a fluororesin, or a modified resin thereof, or a resin containing two or more of these, can be used as the base material of the light reflecting member 140A. For example, particles of an inorganic material or an organic material having a higher refractive index than the base material can be used as the light diffusing material. For example, the light diffusing material can be appropriately selected in the same manner as the light diffusing material used for the first light-transmitting member 131A and the second light-transmitting member 132A described above.

[0115] In this specification, "light reflectivity" refers to a reflectance of 60% or more at the emission peak wavelength of the light emitting element (first light emitting element 121 or second light emitting element 122). It is more beneficial for the reflectance of light reflective member 140A at the emission peak wavelength of the light emitting element to be 70% or more, and even more beneficial for it to be 80% or more.

[0116] 3, a portion of light reflecting member 140A may be located between first light emitting element 121 and substrate 110 and between second light emitting element 122 and substrate 110. By disposing light reflecting member 140A between first light emitting element 121 and substrate 110 and between second light emitting element 122 and substrate 110, it is possible to suppress emission of light from the lower surface side of the light emitting element, thereby obtaining the effect of improving the light utilization efficiency.

[0117] [Wiring layer 160] In the example shown in FIG. 14, light emitting device 100F does not have substrate 110, but has wiring layer 160 disposed on lower surface 140b of light reflective member 140A. Wiring layer 160 is obtained by forming light reflective member 140A, and then forming a conductive film such as a metal film on lower surface 140b and patterning the conductive film. The same material as that of first wiring 11, second wiring 12, and third wiring 13 can be used as the material of wiring layer 160. Wiring layer 160 may be formed as a single layer on lower surface 140b of light reflective member 140A, or may be formed as multiple layers.

[0118] (Exemplary Method for Manufacturing a Light Emitting Device) Next, an exemplary method for manufacturing a light emitting device according to an embodiment of the present disclosure will be outlined with reference to the drawings. Here, an exemplary method for manufacturing a light emitting device 100C shown in FIG.

[0119] First, an aggregate substrate 110X is prepared, which has a first conductive layer 11L on the upper surface 110a and a second conductive layer 12L on the lower surface 110b opposite to the upper surface 110a. The aggregate substrate 110X may be prepared by fabricating the aggregate substrate 110X according to the following steps, or the aggregate substrate 110X may be prepared by purchasing a completed aggregate substrate 110X. FIG. 17 and FIG. 18 each show an example of the appearance of the aggregate substrate 110X as viewed from the upper surface 110a side and an example of the appearance of the aggregate substrate 110X as viewed from the lower surface 110b side, respectively. In this example, conductive members 15 connecting the first conductive layer 11L and the second conductive layer 12L are provided at multiple locations on the aggregate substrate 110X.

[0120] The aggregate substrate 110X can be obtained by forming a conductive film on both sides of a plate-shaped insulating base material by plating or the like, and then patterning the conductive film. As shown in FIG. 17, the first conductive layer 11L includes a plurality of lands 11p. In the configuration illustrated in FIG. 18, a plurality of holes 110h formed using a drill, a laser, or the like are provided on the lower surface 110b of the aggregate substrate 110X, and the second conductive layer 12L is also formed on the inner side surfaces of these holes 110h. Here, an insulating layer 18 is formed on the lower surface 110b side of the aggregate substrate 110X so as to cover a portion of the second conductive layer 12L.

[0121] Next, the first light emitting element 121 and the second light emitting element 122 are prepared. Here, a plurality of sets of the first light emitting element 121 and the second light emitting element 122 are prepared, and as shown in FIG. 19, these sets are two-dimensionally mounted on the upper surface 110a side of the aggregate substrate 110X along the X direction and the Y direction of the figure. At this time, as shown in FIG. 20, the electrodes 24 of the first light emitting element 121 and the second light emitting element 122 are bonded to a plurality of lands 11p of the first conductive layer 11L by the conductive adhesive member 40. As the conductive adhesive member 40, for example, a bump of gold, silver, copper, etc., a conductive paste which is a mixture of a metal powder of gold, silver, copper, platinum, aluminum, etc. and a resin binder, or a tin-silver-copper (SAC)-based or tin-bismuth (SnBi)-based solder can be used.

[0122] Next, a light-transmitting adhesive is applied to the upper surface 121a of the first light-emitting element 121 and the upper surface 122a of the second light-emitting element 122, and a plurality of laminated sheet pieces each including a phosphor layer and a light-transmitting layer are bonded to these upper surfaces. By hardening the adhesive, a first bonding member 151 and a second bonding member 152 can be formed from the adhesive, and as shown in FIG. 21, a first wavelength conversion member 161 and a first light-transmitting member 131X can be arranged above the upper surface 121a of the first light-emitting element 121. Similarly, a second wavelength conversion member 162 and a second light-transmitting member 132X can be arranged above the upper surface 122a of the second light-emitting element 122. The laminated sheet pieces can be obtained, for example, by applying a resin material containing phosphor particles onto a light-transmitting resin sheet, hardening the resin material to obtain a laminated sheet, and cutting the laminated sheet to a predetermined size.

[0123] Next, a material for light reflective member 140A is applied onto upper surface 110a of aggregate substrate 110X and cured to form light reflective resin layer 140X covering multiple pairs of first light emitting elements 121 and second light emitting elements 122, as shown in Fig. 22. At this time, light reflective resin layer 140X has a thickness sufficient to cover the entire first light-transmissive member 131X and second light-transmissive member 132X.

[0124] Next, for example, by cutting using a rotating grinding wheel (blade), a part of the light reflective resin layer 140X, a part of the first light-transmissive member 131X, and a part of the second light-transmissive member 132X are removed along the Y direction of the figure (see FIG. 23). At this time, for example, by moving the blade BL multiple times along the Y direction of the figure, it is possible to make the upper surfaces of the first light-transmissive member 131X and the second light-transmissive member 132X convex, as shown typically in FIG. 24. By this cutting process, the first light-transmissive member 131A and the second light-transmissive member 132A can be formed from the first light-transmissive member 131X and the second light-transmissive member 132X, respectively. It is also possible to obtain the shape of the first surface 131a and the shape of the second surface 132a, each of which is V-shaped in the ZX cross section, by adjusting the shape of the cutting edge of the blade BL.

[0125] Thereafter, the collective substrate 110X and the light-reflective resin layer 140X are cut at positions between the pairs of the first light-emitting elements 121 and the second light-emitting elements 122 (positions indicated by dashed double-dashed lines in Figs. 17 to 19). This singulation process allows the substrate 110 and the light-reflective member 140A to be formed from the collective substrate 110X and the light-reflective resin layer 140X, respectively. Also, the first wiring 11, the second wiring 12, and the third wiring 13 can be formed from the first conductive layer 11L and the second conductive layer 12L. The third wiring 13 corresponds to the portion of the second conductive layer 12L that covered the inner side surface of the hole 110h of the collective substrate 110X. Through the above process, a plurality of light-emitting devices 100C are obtained. EXAMPLES

[0126] Using a ray tracing technique, we evaluated the effect of the shape of the light reflective member and the shape of the light transmissive member of the light emitting device on the optical coupling efficiency with the light guide plate (the proportion of light that enters the light guide plate). Below, we performed a simulation using an optical analysis tool made by Cybernet Systems Co., Ltd.

[0127] Example 1 As a sample of Example 1, a light emitting device having a configuration similar to that of light emitting device 100C shown in Fig. 11 was assumed, and a light distribution in a state in which first surface 131a and second surface 132a of the light emitting device were opposed to a light guide plate was obtained by simulation. However, in the following, the simulation is performed assuming that first convex portion 141, second convex portion 142, and third convex portion 143 of light reflective member 140A have a shape that rises vertically from first surface 131a or second surface 132a in the first cross section.

[0128] In the sample of Example 1, the height H1 of the first convex portion 141 is 0.02 mm. That is, the distance along the Z direction from the first top surface 141t of the first convex portion 141, the second top surface 142t of the second convex portion 142, or the third top surface 143t of the third convex portion 143 to the first top portion 131t of the first surface 131a or the second top portion 132t of the second surface 132a is 0.02 mm. Here, the first surface 131a and the second surface 132a are curved surfaces that rise on the opposite side (+Z direction) from the first light-emitting element 121 and the second light-emitting element 122 in the first cross section, respectively, and the distance along the Z direction in the figure from the end of the first surface 131a to the first top portion 131t and the distance along the Z direction in the figure from the end of the second surface 132a to the second top portion 132t are both 0.02 mm. That is, in the sample of Example 1, the distance from the end of the first surface 131a to the light guide plate along the Z direction in the figure and the distance from the end of the second surface 132a to the light guide plate along the Z direction in the figure (i.e., the maximum distance between the translucent member and the light guide plate) are both 0.04 mm.

[0129] Other basic settings in the simulation are as follows: Wavelength of light emitted from light emitting elements 121 and 122: 455 nm Refractive index of the sapphire substrate in the light emitting elements 121 and 122: 1.77 Refractive index of the semiconductor laminated structure in the light emitting elements 121 and 122: 2.383 Refractive index of bonding members 151 and 152: 1.47 Refractive index of wavelength conversion members 161 and 162: 1.5 Refractive index of light-reflective member 140A: 1.5 Light guide plate material: Acrylic resin Number of rays: 3 million

[0130] Example 2 As a sample of Example 2, a simulation was performed assuming a light emitting device having a configuration similar to that of the light emitting device 100B shown in Fig. 10. That is, in the sample of Example 2, the shape of the first surface 131a and the shape of the second surface 132a in the first cross section were V-shaped with an upward convexity. Here, similar to the sample of Example 1, the height H1 of the first convex portion 141 was set to 0.02 mm, and the distance from the end of the first surface 131a to the light guide plate along the Z direction in the figure and the distance from the end of the second surface 132a to the light guide plate along the Z direction in the figure (i.e., the maximum value of the distance between the light-transmitting member and the light guide plate) were both set to 0.04 mm.

[0131] (Reference example 1) A simulation was performed on the sample of Reference Example 1 in the same manner as the sample of Example 1, except that the distance in the Z direction from the end of first surface 131a to first apex 131t and the distance in the Z direction from the end of second surface 132a to second apex 132t were both set to 0.05 mm, and the heights of first convex portion 141, second convex portion 142, and third convex portion 143 of light reflective member 140A were set to 0 mm. That is, in the sample of Reference Example 1, the simulation was performed assuming that first apex 131t of first surface 131a and second apex 132t of second surface 132a were in contact with the light guide plate.

[0132] (Reference example 2) A simulation was performed on the sample of Reference Example 2 in the same manner as the sample of Reference Example 1, except that the distance in the Z direction from the end of the first surface 131a to the first apex 131t and the distance in the Z direction from the end of the second surface 132a to the second apex 132t were both set to 0.10 mm. That is, in the sample of Reference Example 2, like the sample of Reference Example 1, the first apex 131t of the first surface 131a and the second apex 132t of the second surface 132a are in contact with the light guide plate.

[0133] (Reference example 3) A simulation was performed on the assumption that the light reflective member 140A does not have any of the first convex portion 141, the second convex portion 142, and the third convex portion 143, and the first surface 131a of the first light-transmissive member 131A and the second surface 132a of the second light-transmissive member 132A are both flat surfaces. In the sample of Reference Example 3, it is assumed that the entire light-transmissive member is in contact with the light guide plate.

[0134] (Reference example 4) A simulation was performed on the sample of Reference Example 4 in the same manner as the sample of Reference Example 3, except that the heights of first convex portion 141, second convex portion 142, and third convex portion 143 of light reflective member 140A were set to 0.02 mm. In the sample of Reference Example 4, the distance between the light-transmitting member and the light guide plate is 0.02 mm.

[0135] Figures 25 to 30 show schematic diagrams of calculation results of irradiance at a position 0.1 mm inward from the side surface of the light guide plate for each sample. Figures 25 and 26 show calculation results for the samples of Example 1 and Example 2, respectively. Figures 27 to 30 show calculation results for Reference Examples 1 to 4, respectively.

[0136] (Evaluation of optical coupling efficiency) The proportion of light entering the light guide plate (components excluding Fresnel reflection) was calculated as the optical coupling efficiency for each sample, and the following results were obtained. Example 1: 93.7%, Example 2: 93.7% Reference example 1: 94.0%, Reference example 2: 90.6%, Reference example 3: 98.8%, Reference example 4: 94.4%

[0137] First, it is found that the optical coupling efficiency decreases as the light-transmitting member moves away from the light guide plate from the calculation result of the optical coupling efficiency for the sample of Reference Example 3 and the calculation result of the optical coupling efficiency for the sample of Reference Example 4. Furthermore, when the calculation result of the optical coupling efficiency for the sample of Reference Example 3 is compared with the calculation result of the optical coupling efficiency for the sample of Reference Example 1 and the calculation result of the optical coupling efficiency for the sample of Reference Example 2, it is found that the optical coupling efficiency decreases when the end of the light-transmitting member is farther away from the light guide plate, and the optical coupling efficiency decreases as the distance between the light guide plate and the end of the light-transmitting member increases.

[0138] Here, when comparing the calculation results of the optical coupling efficiency for the samples of Examples 1 and 2 with the calculation results of the optical coupling efficiency for the sample of Reference Example 4, it can be seen that even when the distance between the light guide plate and the light-transmissive member is large, by making first surface 131a and second surface 132a convex, it is possible to obtain an optical coupling efficiency that is comparable to that when first surface 131a and second surface 132a are flat surfaces. [Industrial Applicability]

[0139] The embodiments of the present disclosure are useful for various lighting light sources, in-vehicle light sources, display light sources, etc. In particular, they can be advantageously applied to backlight units for liquid crystal display devices. The light emitting device according to the embodiments of the present disclosure can be advantageously used as a backlight for a display device of a mobile device, which has strict requirements for reducing thickness. [Explanation of symbols]

[0140] 31s (first surface of first light-transmitting member) first inclined surface 31t (first surface of first light-transmitting member) second inclined surface 32s (the second surface of the second light-transmitting member) third inclined surface 32t (of the second surface of the second light-transmitting member) fourth inclined surface 41 (first region on the upper surface of the light-reflective member) 41s (a first inclined region on the upper surface of the light-reflective member) 41t (a second inclined region on the upper surface of the light-reflective member) 42 (a second region on the upper surface of the light-reflective member) 42s (the upper surface of the light-reflective member) third inclined region 42t (fourth inclined region on the upper surface of the light-reflective member) 100A~100F Light emitting device 110 Substrate 121 First light emitting element 122 Second light-emitting element 130 Translucent material 131A, 131B 1st translucent member 131a (first light-transmitting member) first surface 131t (1st side) 1st top 132A, 132B 2nd translucent member 132a (of the second light-transmitting member) second surface 132t (2nd side) 2nd top 140A, 140B, 140D Light-reflective member 141 (light-reflective member) first convex portion 141c (first convex portion of light-reflective member) first side surface 141d (first convex portion of light-reflective member) second side surface 141t (first convex portion of light reflective member) first top surface 142 (of light-reflective member) second convex portion 142c (the second convex portion of the light-reflective member) third side surface 142t (second top surface of second convex portion of light reflective member) 143 (light-reflective member) third convex portion 143d (the fourth side surface of the third convex portion of the light-reflective member) 143t (third convex portion of light-reflective member) third top surface 151: First joining member 160 wiring layer 161 First wavelength conversion member 162 Second wavelength conversion member 163 Wavelength conversion material 200 Light guide plate 300 Backlight

Claims

1. a first light emitting element and a second light emitting element arranged along a first direction, each having an upper surface and a side surface; At least one light-transmitting member having a side surface and covering an upper surface of the first light-emitting element and an upper surface of the second light-emitting element; a light reflective member in contact with at least a portion of a side surface of the first light emitting element, at least a portion of a side surface of the second light emitting element, and a side surface of the light transmissive member; Equipped with the light-transmitting member has a first surface and a second surface exposed from the light-reflecting member, the first surface and the second surface are located above the first light emitting element and above the second light emitting element, respectively; the first surface has a convex shape including a first apex in a first cross section that includes the first direction and is perpendicular to an upper surface of the first light-emitting element, the second surface has a convex shape including a second apex in the first cross section, The upper surface of the light reflective member is a pair of first regions located outside the first surface of the light-transmitting member in a second direction perpendicular to the first direction and each of the first regions aligned with the first surface; a pair of second regions located outside the second surface of the light-transmitting member in the second direction and each of which is aligned with the second surface; having the light reflective member has a first convex portion located between the first surface and the second surface in the first direction, the first convex portion including a portion located above the first apex of the first surface and the second apex of the second surface in the first cross section, a shape of the first surface in a second cross section perpendicular to the first direction is flat, and a shape of the second surface in the second cross section is flat.

2. the light reflective member further includes a second convex portion and a third convex portion located above both end portions of the first surface of the light transmissive member in the first direction and both end portions of the second surface of the light transmissive member in the first direction, the second convex portion is located on an opposite side to the first convex portion with respect to a position of the first surface in the first direction, The light emitting device according to claim 1 , wherein the third convex portion is located on an opposite side to the first convex portion with respect to a position of the second surface in the first direction.

3. The light emitting device according to claim 1 , wherein each of the first surface and the second surface has a curved shape in the first cross section.

4. The first surface is a first inclined surface that becomes increasingly separated from an upper surface of the first light emitting element from one end portion toward a center portion in the first cross section; a second inclined surface that is spaced apart from the top surface of the first light-emitting element from the other end toward the center in the first cross section; Including, The second surface is a third inclined surface that becomes increasingly separated from the upper surface of the second light emitting element from one end portion toward a central portion in the first cross section; a fourth inclined surface that becomes more distant from the upper surface of the second light-emitting element from the other end toward the center in the first cross section; 3. The light emitting device according to claim 1 or 2, comprising:

5. The pair of first regions are a pair of first inclined regions each aligned with the first inclined surface of the light-transmitting member; a pair of second inclined regions each aligned with the second inclined surface of the light-transmitting member; Including, The pair of second regions are a pair of third inclined regions each aligned with the third inclined surface of the light-transmitting member; a pair of fourth inclined regions each aligned with the fourth inclined surface of the light-transmitting member; The light emitting device of claim 4 .

6. The at least one light-transmitting member is a first light-transmissive member located above an upper surface of the first light-emitting element; a second light-transmitting member located above an upper surface of the second light-emitting element; Including, The light emitting device according to claim 1 , wherein the first light-transmissive member and the second light-transmissive member each have the first surface and the second surface.

7. a first wavelength conversion member located between the first light-transmissive member and the first light-emitting element; a second wavelength conversion member located between the second light-transmitting member and the second light-emitting element; The light emitting device of claim 6 further comprising:

8. a substrate supporting the first light emitting element and the second light emitting element; The light emitting device according to claim 1 , wherein the light reflective member covers at least a portion of an upper surface of the substrate.

Images