US-12620772-B2 - Light emitting device

US12620772B2US 12620772 B2US12620772 B2US 12620772B2US-12620772-B2

Abstract

A light emitting device includes: a base having a mounting surface; one or more light reflective members arranged on the mounting surface and providing one or more light reflective surfaces on one virtual plane; a first light-emitting element having a first light-exiting surface facing toward the one or more light reflective surfaces, arranged on the mounting surface such that the first light-exiting surface is oblique relative to the one or more light reflective surfaces, and wherein light emitted from the first light-exiting surface is irradiated on the one or more light reflective surfaces; and a second light-emitting element having a second light-exiting surface facing toward the one or more light reflective surfaces, arranged on the mounting surface such that the second light-exiting surface is oblique relative to the first light-exiting surface, and wherein light emitted from the second light-exiting surface is irradiated on the one or more light reflective surfaces.

Inventors

Tadayuki Kitajima

Assignees

NICHIA CORPORATION

Dates

Publication Date: 20260505
Application Date: 20210602
Priority Date: 20200608

Claims (16)

1 . A light emitting device, comprising: a base having a mounting surface; one or more light reflective members arranged on the mounting surface and comprising one or more co-planar light reflective surfaces that are oblique relative to the mounting surface; a first light-emitting element having a first light-exiting surface facing toward the one or more co-planar light reflective surfaces, arranged on the mounting surface such that the first light-exiting surface is oblique relative to the one or more co-planar light reflective surfaces in a top view, wherein light emitted from the first light-exiting surface is irradiated directly on the one or more co-planar light reflective surfaces; a first submount on which the first light-emitting element is disposed; a second light-emitting element having a second light-exiting surface facing toward the one or more co-planar light reflective surfaces, arranged on the mounting surface such that the second light-exiting surface is oblique relative to the first light-exiting surface in the top view, wherein light emitted from the second light-exiting surface is irradiated directly on the one or more co-planar light reflective surfaces; and a second submount on which the second light-emitting element is disposed, wherein: the one or more co-planar light-reflective surfaces face in a direction that is inclined upward and away from a side of the light emitting device on which the first and second light-emitting elements are located, and light from the first light-emitting element and light from the second light-emitting element reflected by the one or more co-planar light reflective surfaces are brought closer to each other before entering a light extraction region of the light emitting device.
2 . The light emitting device according to claim 1 , wherein: the first light-emitting element is a first semiconductor laser element having an upper surface, a lower surface and a side surface that serves as the first light-exiting surface; light emitted from the first light-exiting surface and passing through an optical axis travels in a first direction from the first light-exiting surface to be irradiated on the one or more co-planar light reflective surfaces; the second light-emitting element is a second semiconductor laser element having an upper surface, a lower surface and a side surface that serves as the second light-exiting surface; and light emitted from the second light-exiting surface and passing through an optical axis travels in a second direction, which is different from the first direction, from the second light-exiting surface to be irradiated on the one or more co-planar light reflective surfaces.
3 . The light emitting device according to claim 2 , further comprising a third semiconductor laser element having an upper surface, a lower surface and a side surface that serves as a third light-exiting surface from which light is emitted, wherein light emitted from the third light-exiting surface and passing through an optical axis travels in a third direction, which is different from the first direction and the second direction, from the third light-exiting surface to be irradiated on the one or more co-planar light reflective surfaces.
4 . The light emitting device according to claim 3 , further comprising a wavelength conversion member on which light emitted from the first semiconductor laser device and reflected by the one or more light reflective members, light emitted from the second semiconductor laser device and reflected by the one or more light reflective members, and light emitted from the third semiconductor laser device and reflected by the one or more light-emitting members are incident.
5 . The light emitting device according to claim 4 , wherein: the wavelength conversion member has a light extraction region; and at least a portion of the light extraction region of the wavelength conversion member overlaps with a portion of a region where the one or more co-planar light reflective surfaces are provided as the mounting surface is viewed from above.
6 . The light emitting device according to claim 3 , wherein a parallel direction of the one or more co-planar light reflective surfaces and the third direction are orthogonal to each other.
7 . The light emitting device according to claim 3 , wherein the first semiconductor laser element and the second semiconductor laser element are arranged in line symmetry with respect to the third direction as the mounting surface is viewed from above.
8 . The light emitting device according to claim 3 , wherein: where the one or more co-planar light reflective surfaces are bisected along a plane, as a boundary, that is perpendicular to the mounting surface and that passes through an optical axis of light emitted from the third semiconductor laser element and through a straight line extending in the third direction, a region on a side where the first semiconductor laser element is arranged is a first reflection region and a region on a side where the second semiconductor laser element is arranged is a second reflection region; light emitted from the first semiconductor laser element and passing through an optical axis is irradiated on the first reflection region; and light emitted from the second semiconductor laser element and passing through an optical axis is irradiated on the second reflection region.
9 . The light emitting device according to claim 3 , wherein as the mounting surface is viewed from above, an intersection between a straight line that extends in the first direction and passes through an optical axis of light emitted from the first semiconductor laser element and a straight line that extends in the second direction and passes through an optical axis of light emitted from the second semiconductor laser element is on a straight line that extends in the third direction and passes through an optical axis of light emitted from the third semiconductor laser element and is outside of the one or more reflective surfaces.
10 . The light emitting device according to claim 1 , wherein: the one or more light reflective members are formed by one light reflective member; and the one or more reflective surfaces are formed by one reflective surface provided on the one light reflective member.
11 . The light emitting device according to claim 4 , wherein: the wavelength conversion member has a light extraction region, in a top view, a distance between the first light-emitting element and the second light emitting element is greater than a length of the light extraction region in the same direction as this distance, and in a top view, the first light-emitting element and the second light emitting element are most distance from each other among the first light-emitting element, the second light-emitting element, and the third light-emitting element.
12 . The light emitting device according to claim 11 , wherein: the wavelength conversion member includes a wavelength conversion portion and a surrounding portion, the wavelength conversion portion having a light input surface and one or more lateral surfaces, the surrounding portion surrounding the one or more lateral surfaces of the wavelength conversion portion, and the light extraction region is included in the wavelength conversion portion and encircled by the surrounding portion.
13 . The light emitting device according to claim 12 , wherein: in a top view, a length of the light input surface of the wavelength conversion portion in the parallel direction of one or more co-planar light reflective surfaces is shorter than a length of the light input surface in the direction perpendicular to the parallel direction.
14 . The light emitting device according to claim 7 , wherein the first semiconductor laser element and the third semiconductor laser element are not arranged in line symmetry with respect to the second direction as the mounting surface is viewed from above.
15 . The light emitting device according to claim 14 , wherein the second semiconductor laser element and the third semiconductor laser element are not arranged in line symmetry with respect to the first direction as the mounting surface is viewed from above.
16 . The light emitting device according to claim 1 , wherein: the base having one or more inner lateral surfaces and uppermost upper surface by which the mounting surface is surrounded in a top view, a center point of the mounting surface in the direction perpendicular to the parallel direction of one or more co-planar light reflective surfaces is included in the one or more co-planar light reflective surfaces.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This is a national stage application of PCT Application No. PCT/JP2021/020974, filed on Jun. 2, 2021, which claims priority to Japanese Patent Application No. 2020-099015, filed on Jun. 8, 2020. BACKGROUND The present disclosure relates to a light emitting device. Japanese Patent Publication No. 2020-21761 discloses a light-source device, wherein light emitted from a plurality of light-emitting elements are reflected by the reflective surface of a stand-up mirror to be emitted to the outside. SUMMARY With the light-source device of Japanese Patent Publication No. 2020-21761, optical axes of light emitted from the light-emitting elements are parallel to each other. Therefore, it is believed that normally a light extraction region is ensured whose length is equal to or greater than the distance between the emission points of light-emitting elements that are arranged at opposite ends. On the other hand, not all light emitting devices are required to have a wide light extraction region as in Japanese Patent Publication No. 2020-21761. Depending on the size of the light extraction region and the characteristics of the light extracted therefrom, there is room for improvement in the arrangement of the components in a light emitting device. A light emitting device disclosed herein includes: a base having a mounting surface; one or more light reflective members arranged on the mounting surface and providing one or more light reflective surfaces on one virtual plane; a first light-emitting element having a first light-exiting surface facing toward the one or more light reflective surfaces, arranged on the mounting surface such that the first light-exiting surface is oblique relative to the one or more light reflective surfaces in a top view, and wherein light emitted from the first light-exiting surface is irradiated on the one or more light reflective surfaces; and a second light-emitting element having a second light-exiting surface facing toward the one or more light reflective surfaces, arranged on the mounting surface such that the second light-exiting surface is oblique relative to the first light-exiting surface in a top view, and wherein light emitted from the second light-exiting surface is irradiated on the one or more light reflective surfaces, wherein light from the first light-emitting element and light from the second light-emitting element reflected by the one or more light reflective surfaces are brought closer to each other before entering a light extraction region of the light emitting device. According to an embodiment of the present disclosure, a light emitting device is realized in which light from a plurality of light-emitting elements are condensed onto a light extraction region, and the light is extracted effectively. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a light emitting device according to an embodiment. FIG. 2 is a top view corresponding to FIG. 1. FIG. 3 is a cross-sectional view of the light emitting device taken along line III-III of FIG. 2. FIG. 4 is a perspective view for illustrating the internal structure of the light emitting device according to an embodiment. FIG. 5 is a perspective view for illustrating the internal structure of the light emitting device according to an embodiment. FIG. 6 is a top view corresponding to FIG. 5. FIG. 7 is a perspective view showing a wavelength conversion member and a light-transmissive member bonded together according to an embodiment. FIG. 8 is a top view corresponding to FIG. 7. FIG. 9 is a top view seen through the upper surface of the wavelength conversion member for illustrating the bonding surface between the light-transmissive member and the wavelength conversion member according to an embodiment. FIG. 10 is a bottom view of the wavelength conversion member according to an embodiment. FIG. 11 is a top view of the light-transmissive member according to an embodiment. FIG. 12 is an image representing the intensity distribution of light irradiated on the light reflective surface of the light emitting device according to an embodiment. FIG. 13 is an image representing the intensity distribution of light incident on the wavelength conversion portion of the light emitting device according to an embodiment. DETAILED DESCRIPTION For the scope of the present specification and the claims, the term “polygon” (e.g., a triangle or a rectangle) encompasses those with rounded corners, chamfered corners or beveled corners. The term “polygon” also encompasses those in which an intermediate portion of a side (as opposed to a corner, i.e., the end of the side), is deformed. That is, any shape that is obtained by partially deforming a polygon falls within the meaning of a “polygon” as defined in the present specification and the claims. This applies not only to “polygon” but also to any term representing a particular shape such as a trapezoid, a circle or a convex/concave shape. This also appli