Light emitting device

Abstract

To provide a light-emitting device capable of improving optical coupling efficiency from a light-emitting element to a light transmission member, and achieving high-luminance light emission with high light emission efficiency.SOLUTION: A light transmitting member having a light emitting surface and a light receiving surface of the light emitting device; a light emitting element having an exit surface facing the light receiving surface, the light emitting element being bonded to the light transmitting member; A light guide member that guides the light emitted from the light emitting element to the light transmissive member, wherein the light guide member includes a bonding region in which an emitting surface of the light emitting element and a light receiving surface of the light transmissive member are bonded to face each other, and a first covering region that extends from the bonding region and covers a surface of one of the light emitting element and the light transmissive member protruding outward from the bonding region, and a first reflecting surface that reflects the emitted light toward the light transmissive member is provided on an outer surface of the first covering region.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light emitting device, and more particularly to a light emitting device provided with a light guiding member that enhances light emitting efficiency. [Background technology]

[0002] In recent years, light-emitting devices incorporating semiconductor light-emitting elements such as light-emitting diodes (LEDs) and laser diodes (LDs) as light sources have been used in various lighting and display devices. These semiconductor light-emitting elements, in particular, have attracted attention as light sources for next-generation lighting that can replace fluorescent lamps due to their low power consumption and long life. Further improvements in light output and luminous efficiency are required. Furthermore, there is a demand for light sources with good light distribution characteristics and high brightness, such as for floodlights such as car headlights.

[0003] For example, Patent Document 1 proposes a light-emitting device in which an LED chip assembly, in which a phosphor chip is fixed to an LED chip with a light-transmitting adhesive, is mounted on the cup portion of a lead frame or on an insulating substrate, and the LED chip assembly is sealed with a protective layer or sealing resin mixed with a light-scattering agent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-141559 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-019096 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-305328 [Patent Document 4] Japanese Patent Application Publication No. 10-151794 [Patent Document 5] Japanese Patent Application Laid-Open No. 2009-043764 [Patent Document 6] Japanese Patent Application Laid-Open No. 2008-300621 [Patent Document 7] Japanese Patent Application Laid-Open No. 2008-277592 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the light-emitting device described in Cited Document 1, the optically transparent adhesive used to bond the phosphor chip to the LED chip may drip directly from the phosphor chip or along the side of the light-emitting element onto the cup portion of the lead frame or the insulating substrate. This causes the light emitted from the LED chip or phosphor chip to be guided by the adhesive and absorbed by the insulating substrate, the electrodes provided thereon, or the surface of the lead frame, resulting in a decrease in the light output of the light-emitting device. Similar problems also exist with the optically transparent resin that coats the light-emitting element or phosphor chip and the surfaces of the substrate, electrodes, etc. Furthermore, even if the optical path through such optically transparent materials is small and narrow, it can have a significant impact on the characteristics of the light-emitting device. Furthermore, the LED chip and phosphor chip in Cited Document 1 are merely fixed together at their opposing surfaces with an adhesive, resulting in low coupling efficiency of light emitted from the LED chip to the phosphor chip. Furthermore, poor matching of the external shapes of the two may result in uneven brightness, color, and poor directivity.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a light-emitting device that can reduce the loss of light emitted from a light-emitting element, increase the utilization efficiency of the light, increase the optical coupling efficiency from the light-emitting element to a light-transmitting member, and increase the light-emitting efficiency and brightness. [Means for solving the problem]

[0007] The light emitting device according to the present invention can achieve the above object by having the following configurations (1) to (15). (1) A light emitting device comprising: a light-transmitting member having a light-emitting surface and a light-receiving surface; a light-emitting element having an exit surface facing the light-receiving surface and joined to the light-transmitting member; and a light-guiding member extending from the surface of the light-emitting element to the surface of the light-transmitting member and guiding light emitted from the light-emitting element to the light-transmitting member, wherein the light-guiding member has a joining region that joins the exit surface of the light-emitting element and the light-receiving surface of the light-transmitting member so that they face each other, and a first covering region that extends from the joining region and covers one surface of the light-emitting element and the light-transmitting member that protrudes outward from the joining region, and a first reflecting surface that reflects the emitted light toward the light-transmitting member is provided on the outer surface of the first covering region. (2) The light emitting device according to (1) above, further comprising a covering member having a light-reflecting material, the covering member covering the surface of the light-guiding member, exposing the light-emitting surface and covering the surfaces of the light-emitting element and the light-transmitting member. (3) The light emitting device according to (1) or (2), wherein the light transmitting member is a wavelength converting member that is excited by the light emitted from the light emitting element. (4) A light-emitting device according to any one of (1) to (3) above, wherein the first covering region covers the protruding surface of one of the light-emitting element and the light-transmitting member and the other side surface, and the first reflecting surface is provided opposite the side surface. (5) The light-emitting device described in (4) above, wherein the covering member covers the surface of the other side surface via the light-guiding member of the first covering region, and covers the surface of the side surface of the light-emitting element or light-transmitting member exposed from the light-guiding member. (6) A light-emitting device according to any one of (1) to (5) above, wherein a portion of the light-receiving surface of the light-transmitting member protrudes outward from the light-emitting surface, and the first reflecting surface is an inclined surface inclined from the side surface of the light-emitting element toward the light-receiving surface. (7) The light-emitting device according to (6), wherein the light-receiving surface of the light-transmitting member is larger than the light-emitting surface of the light-emitting element and includes the light-emitting surface. (8) A light-emitting device according to any one of (1) to (5) above, wherein a portion of the light-emitting element's light-emitting surface protrudes outward from the light-receiving surface, and the first reflecting surface is an inclined surface inclined from the side surface of the light-transmitting member toward the light-emitting surface. (9) The light-emitting device according to (8), wherein the light-emitting surface of the light-emitting element is larger than the light-receiving surface of the light-transmitting member and includes the light-receiving surface. (10) A light-emitting device according to any one of (1) to (9), wherein the light-emitting elements are spaced apart from one another and bonded to the light-receiving surface side of the light-transmitting element, the light-guiding element has a second covering region extending from the bonding region to cover a portion of the light-receiving surface sandwiched between the spaced apart light-emitting elements, and a second reflecting surface is provided on the outer surface of the second covering region to reflect the light emitted from each of the adjacent light-emitting elements toward the light-receiving surface. (11) The light emitting device according to (10), wherein the second covering region covers opposing side surfaces of the spaced apart light emitting elements. (12) The light emitting device according to (10) or (11), wherein at least one set of the plurality of light emitting elements has a different distance from the light emitting surface to the light receiving surface of the light transmitting member. (13) A light-emitting device according to any one of (1) to (12) above, wherein the light-emitting element has a semiconductor layer and a substrate on the light-emitting surface side of the semiconductor layer, and the light-guiding member extends to cover the side surface of the substrate, exposing the side surface of the semiconductor. (14) The light emitting device according to any one of (1) to (13) above, further comprising a covering member that contains a light reflective material, exposes the light emitting surface, and covers the light emitting element and a part of the light transmitting member, and the first reflecting surface or the second reflecting surface is provided at the interface between the light guiding member and the covering member. (15) The light emitting device according to any one of (1) to (14) above, wherein the first reflecting surface or the second reflecting surface is a convex curved surface that is convex toward the side surface. [Effects of the Invention]

[0008] According to the present invention, by joining a light-transmitting member and a light-emitting element arranged opposite each other with a light-guiding member provided between them and in the area extending therefrom, light can be efficiently extracted from the light-emitting element, guided, and optically coupled to the light-transmitting member, thereby providing a light-emitting device capable of emitting light with high luminous efficiency and high brightness. Furthermore, by further covering the light-transmitting member and the light-emitting element joined by the light-guiding member with a light-reflective coating member to form a light-emitting device with a light-emitting surface on a portion of the light-transmitting member, light can be guided even more efficiently. Furthermore, when the light-transmitting member is a wavelength conversion member, a light-emitting device can be provided that has light distribution characteristics with little color unevenness, high luminous efficiency, and high-brightness emission. Furthermore, with this structure, the outer shapes, sizes, and positions of the light-emitting element and the light-transmitting member can be made different, thereby creating a light source with a desired shape and outer dimensions, thereby providing a light-emitting device that is easily miniaturized and can further adjust light-emitting characteristics such as luminous flux and brightness as appropriate. [Brief explanation of the drawings]

[0009] [Figure 1] 1A is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention taken along line AA of FIG. 1B; [Figure 2] 1 is a schematic cross-sectional view illustrating the periphery of a light source unit of a light emitting device according to an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic cross-sectional view illustrating the periphery of a light source unit of a light-emitting device according to a comparative example of the present invention. [Figure 4] 1 is a schematic cross-sectional view of a light-emitting element according to an embodiment of the present invention. [Figure 5] 1A is a schematic cross-sectional view of a light-emitting device according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view illustrating the periphery of a light source unit thereof. [Figure 6] 1 is a schematic cross-sectional view illustrating the periphery of a light source unit of a light emitting device according to an embodiment of the present invention. [Figure 7] 1 is a schematic cross-sectional view illustrating the periphery of a light source unit of a light emitting device according to an embodiment of the present invention. [Figure 8] 1 is a schematic cross-sectional view illustrating a light emitting device according to an embodiment of the present invention. [Figure 9] 1 is a schematic cross-sectional view illustrating a light emitting device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes embodiments of the invention with reference to the accompanying drawings. However, the light-emitting element and device described below are intended to embody the technical concept of the present invention and do not limit the present invention to the following. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention, and are merely illustrative examples, unless otherwise specified. Note that the size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, the elements constituting the present invention may be configured with the same material, so that one component serves multiple functions, or conversely, the function of one component may be shared by multiple components. Similarly, in each of the embodiments described below, various configurations may be combined as appropriate unless otherwise specified.

[0011] 1 and 2, the light-emitting device of the present invention is mainly composed of a light-emitting element 10, a light-transmitting member 20, and a light-guiding member 30. The light-emitting element 10 has an emission surface, and the light-transmitting member 20 has a surface 21 (light-emitting surface 90) exposed to the outside, a light-receiving surface 22 opposite the surface 21, and side surfaces. The light-emitting element 10 is disposed with its emission surface facing the light-receiving surface 22 of the light-transmitting member, and one of the light-emitting element 10 and the light-transmitting member 20 protrudes outward beyond the other. The light-guiding member 30 can be made of an adhesive that fastens the light-emitting element 10 and the light-transmitting member 20. The light-guiding member 30 is translucent and extends between the surface of the light-emitting element and the surface of the light-transmitting member, specifically from the surface of the light-emitting element to the surface of the light-transmitting member, and has the function of guiding light emitted from the light-emitting element 10 to the light-transmitting member 20. This light-guiding member 30 has a bonding region 31 that bonds the opposing light-emitting element's emission surface and the light-receiving surface 22 of the light-transmitting member, and a covering region (32, 37) that extends from this bonding region and covers the protruding surface (part of the light-emitting element's emission surface or the light-receiving surface 22 of the light-transmitting member). The light-guiding member is spaced from the mounting surface of the substrate and is positioned toward the light-transmitting member 20, recessed from the mounting surface of the light-emitting element 10. This prevents light emitted from the light-emitting element 10 from propagating through the light-guiding member 30 and being guided to the substrate 50 and being absorbed. A reflective surface that reflects the light emitted from the light-emitting element 10 toward the light-transmitting member 20 is provided on the outer surface of the covering region. In this way, the reflection on the outer surface of the light-guiding member 30 suppresses light diffusion and focuses the light within the light-guiding member 30, allowing the light to be guided to the light-transmitting member 20. This reduces light loss due to absorption and allows the light emitted from the light-emitting element 10 to be efficiently coupled to the light-transmitting member 20, improving the luminance distribution of the light-emitting surface. Furthermore, by joining the light-emitting element and the light conversion member, it is possible to achieve a good distribution of luminance and chromaticity within the light-emitting surface.

[0012] 1, 2, 5, and 6, the covering region is preferably formed so as to connect the surface of the protrusion with the other side surface, and the reflecting surface is provided on the outer surface of the light-guiding member facing the covered side surface. By forming the inclined surface connecting the surface of one protrusion with the other side surface as the outer surface, the outward bulging of the covering region is suppressed, shortening the optical path length of light reflected on the outer surface to the light-transmitting member 20. Furthermore, since the outer surface is a concave curved surface, it becomes a convex curved reflecting surface, thereby improving the light-guiding function of the light-guiding member 30.

[0013] Furthermore, as shown in FIGS. 1 and 2 , the light-emitting device of the present invention may further include a light-reflective covering member 40. By covering a portion of the light-emitting element 10 and the light-transmitting member 20 with this covering member 40, the exposed surface 21 of the light-transmitting member can serve as the light-emitting surface 90 of the device, thereby forming a surface-emitting light-emitting device. The covering member 40 also functions as a filler or sealant containing a light-reflective material 45, thereby enabling the miniaturization of the light-emitting device. Furthermore, by covering the surface of the light-guiding member 30 with its light-reflecting properties, the covering member can enhance its light-guiding function and further improve the optical coupling efficiency of light emitted from the light-emitting element 10 to the light-transmitting member. Furthermore, it is preferable to provide regions on the surfaces of the light-emitting element and the light-transmitting member that are covered by the light-guiding member and regions that are exposed from the covered region, and to cover these regions with the covering member. That is, the exposed region is covered directly by the covering member, and the covered region is covered via the light-guiding member. Specifically, the covering member covers one side surface of the covered region via the light-guiding member 30, and covers the other side surface exposed from the light-guiding member 30. As a result, the light-reflecting function of the covering member strengthens the light confinement effect in the light-guiding member 30 in the covered region, while the exposed region restricts the light propagation region from the light-emitting element 10 to the light-transmitting member 20, allowing the light-guiding member 30 to efficiently guide the light to the light-transmitting member 20. Furthermore, the reflective surface of the covered region is preferably provided at the interface between the light-guiding member and the covering member, further enhancing this function. This configuration improves the utilization efficiency of light emitted from the light-emitting element 10, achieving high-brightness light emission with little color unevenness and excellent light distribution characteristics.

[0014] (Embodiment 1) 1 and 2 show a light-emitting device 100 according to a first embodiment of the present invention. The cross section in FIG. 1(a) is a schematic top cross section taken along line AA in FIG. 1(b), and FIG. 2 is a schematic cross section of the light source and its surroundings. The light-emitting device 100 shown in FIG. 1 is a surface-emitting light-emitting device having a light-emitting surface 90. The light-emitting device 100 mainly comprises a light-emitting element 10 having a semiconductor element structure 11 on a growth substrate 1, a plate-shaped light-transmitting member 20 having an exposed surface 21 serving as the light-emitting surface 90 and a light-receiving surface 22 facing the surface 21, a light-guiding member 30 that guides light emitted from the light-emitting element 10 to the light-transmitting member 20, and a covering member 40 containing a light-reflective material 45. The light-emitting element 10 is flip-chip mounted on a wiring layer 51 of a substrate 50, with its light-emitting surface, which is the back surface of the growth substrate 1, facing the light-receiving surface 22 of the light-transmitting member. The light-emitting element 10 is optically coupled to the light-transmitting member 20 via the intervening light-guiding member 30. A frame 55 is provided on the substrate 50, surrounding the light-emitting element 10 and the light-transmitting member 20. The inside of the frame 55 is filled with a covering member 40, which partially covers the light-emitting element 10 and the light-transmitting member 20. The light-emitting region, i.e., the light-emitting window, of this light-emitting device 100 is substantially limited to the surface 21 of the light-transmitting member 20, resulting in a surface-emitting light-emitting device with this surface 21 as the light-emitting surface 90. Furthermore, the light-emitting device 100 can control the brightness and light distribution of the light emitted from the surface 21, i.e., the light-emitting surface 90, by adjusting the shape and size of the surface 21 of the light-transmitting member 20. Furthermore, the light-emitting device has relatively uniform brightness and chromaticity within the light-emitting surface. Here, the planar shapes of the light-transmitting member and the light-emitting element are rectangular, as shown in the figure, and the light-emitting element is enclosed within the light-transmitting member in plan view.

[0015] 2, the light source unit will be described in detail. The light guide member 30 has a bonding region 31 that bonds the light emitting element 10 and the light transmitting member 20 so that they face each other. More specifically, the bonding region is provided in a region of the light receiving surface 22 of the light transmitting member that faces the emission surface of the light emitting element 10. In specific examples, such as the examples described below, the thickness of the bonding region is approximately 0.01 μm to 100 μm. The presence of the light guide member 30 in the bonding region separates the light emitting element and the light transmitting member, which reduces the refractive index difference at the emission surface of the light emitting element 10 compared to when a gas such as air is present, allowing light to be extracted more efficiently from the light emitting element 10. Therefore, light from the emission surface of the light emitting element 10 is transmitted through the bonding region 31 and directly optically coupled to the light receiving surface 22 of the light transmitting member.

[0016] In this embodiment, the light-receiving surface 22 of the light-transmitting member is larger than the light-emitting surface of the light-emitting element 10 and encloses it, with a portion of the light-receiving surface 22 protruding outward from the light-emitting surface of the light-emitting element 10. In other words, the side surface of the light-transmitting member 20 is located outward from the side surface of the light-emitting element 10, with a protruding portion provided along the entire periphery. In this light-emitting device 100, the light-emitting surface 90 of the light-emitting device serves as a light-emitting window that is relatively larger than the light-emitting surface of the element, thereby increasing the luminous flux of the emitted light. The light-guiding member 30 has a first covering region 32 that extends from the above-mentioned bonding region 31 and covers the protruding surface of the light-transmitting member and the side surface of the light-emitting element 10 that hangs down from a portion of the side surface. Specifically, this region is provided in a region that protrudes outward from the bonding region. Here, light emitted from the light-emitting element 10 is typically emitted not only from the light-emitting surface but also from the side and bottom (mounting surface) sides. Therefore, a portion of the light is incident on the first covering region 32, mainly from the side surface of the light-emitting element, and is guided there. That is, as in the case of the bonding region described above, the first covering region 32 also reduces the refractive index difference of the emitting surface of the light-emitting element, thereby improving the light extraction efficiency. Here, the outer surface of the first covering region 32 facing the covering member 40, i.e., the outer surface of the first covering region 32 facing the side surface of the light-emitting element 10, has a first reflecting surface 33 that reflects the emitted light from the light-emitting element 10 toward the light-transmitting member 20. Therefore, the reflected light of the emitted light is reflected by the first reflecting surface 33 toward the light-receiving surface 22 of the light-transmitting member 20 and guided thereto, and is optically coupled to the light-transmitting member 20. In this way, by first extracting the light emitted laterally from the light-emitting element 10 into the light-guiding member 30 and then reflecting it by the first reflecting surface 33, light loss due to absorption within the light-emitting element 10 can be reduced compared to a configuration in which the light-emitting element 10 is exposed from the light-guiding member and directly covered with the light-reflective covering member 40. Furthermore, the light propagates and spreads within the light-guiding member, thereby improving the optical coupling efficiency and light-emitting characteristics.

[0017] As described above, in this embodiment, as shown in FIGS. 1 and 2 , providing the first reflective surface 33 of the light-guiding member 30 at the interface with the covering member 40 enhances the reflective function. Furthermore, since the interface is composed of the light-transmissive light-guiding member 30 and the covering member 40, which contains a light-reflective material in a translucent base material, it forms a gentle reflective interface that seeps into the covering member. This configuration can be easily formed by forming the first covering region 32 on the light-guiding member 30 and then filling it with the covering member 40, making it a structure that is highly suitable for mass production. Note that the first reflective surface 33 does not necessarily have to be provided at the interface with the covering member 40. For example, the outer surface of the first covering region 32 facing the covering member 40 may be separated from the covering member 40, leaving a gap therebetween, and the first reflective surface 33 may be provided at the interface between the light-guiding member 30 and air. According to this configuration, the light-guiding member 30 side at this interface has a high refractive index, allowing a large amount of light to be reflected within the first covering region 32. Furthermore, it is also possible to reflect again the light components transmitted into the gap from the first covered region 32 on the surface of the covering member 40. In addition to this configuration, for example, the first reflecting surface 33 may be formed by providing on the outer surface of the first covered region 32 a highly reflective metal film such as silver (Ag) or aluminum (Al), a dielectric multilayer film, or a layer made of translucent particles.

[0018] Furthermore, in the light-emitting device 100, the surface of the first covered region 32 facing the side surface of the light-emitting element 10 is preferably an inclined surface inclined from the side surface toward the light-receiving surface 22 of the light-transmitting member. This allows light emitted laterally from the light-emitting element 10 to be reflected favorably toward the light-receiving surface 22 of the light-transmitting member, and also allows for favorable optical coupling due to the cross-sectional width expanding toward the protruding surface. Furthermore, while this inclined surface may be flat, it is preferable that it be a convex curved surface that is convex toward the bonding region 31, since this increases the surface area of ​​the first reflecting surface 33 compared to a flat surface, thereby improving the light reflection efficiency.

[0019] The method for forming the first covered region 32 is not particularly limited, but it can be formed, for example, by applying an appropriate amount of the resin material that constitutes the light-guiding member 30 onto the emission surface of the light-emitting element 10, and then mounting the light-transmitting member 20. At this time, the light-transmitting member 20 may be pressed appropriately. The resin can be applied by a dispensing method, a stamping method, or the like, and the light-transmitting member 20 can be mounted in mass production using a die-bonding device equipped with a collet that can adsorb, transport, and press the light-transmitting member 20.

[0020] The resin material constituting the light-guiding member 30 may drip directly from the protruding portion of the light-emitting element 10 or the light-transmitting member 20 or down the side surface of the light-emitting element 10 and reach the mounting substrate 50. FIG. 3 is a schematic cross-sectional view illustrating an embodiment in which a hanging portion is provided in such a light-guiding member 36. In this embodiment, which is compared to the present invention, as shown in FIG. 3, when the adhesive resin of the light-guiding member 36 continuously drips down the side surface of the light-emitting element 10 onto the mounting substrate 50, an optical path is formed in the hanging portion. As a result, light emitted laterally or downward from the light-emitting element 10 is guided toward the mounting substrate 50 by the hanging portion and reaches the surface of the mounting substrate 50 or the wiring 51, resulting in optical loss due to absorption. Furthermore, the formation of the hanging portion may block the formation of an underfill 70 or the infiltration of the covering member 40 into the region between the light-emitting element 10 and the substrate 50, resulting in light leakage due to the resulting cavity, resulting in optical loss. In particular, if the amount of resin material applied is too large, the light-guiding member 36 may hang down directly from the protruding portion of the light-transmitting member 20 onto the substrate 50, or may separate from the bonding region and bridge the light-emitting element 10 and the substrate 50, forming an optical path similar to the above, which may result in light loss. Furthermore, in the third embodiment described below, a hanging portion may be provided that covers the side surface and reaches the mounting substrate in a similar manner, although this structure is more difficult to form than when the light-transmitting member protrudes as in this embodiment. Therefore, the amount of resin material applied is appropriately adjusted so as not to be excessive, and is also adjusted by adjusting the area of ​​the protruding surface and the position of the protruding portion, as described below.

[0021] Therefore, the outer surface of the first covered region 32 is preferably located closer to the light-transmitting member 20 than the bottom surface and mounting surface of the light-emitting element 10, and the area covered by the first covered region 32 preferably extends halfway along the side surface of the light-emitting element 10. That is, as shown in FIGS. 1 and 2 , it is desirable that the side surface of the light-emitting element 10 has a covered region (first covered region 32) on the emission surface (upper) side relative to the light-guiding member and an exposed region on the bottom surface and mounting surface (lower) side. Furthermore, it is preferable that this exposed region be covered with the covering member 40. More specifically, when the light-emitting element 10 has a semiconductor layer 11 as an element structure and a substrate 1 on the emission surface side of the semiconductor layer, it is preferable that the light-guiding member 30 extends to cover the side surface of the substrate, exposing the side surface of the semiconductor layer 11. This improves the light reflectivity of the semiconductor layer 11 side, including the light-emitting layer, while improving the light transmittance of the substrate side. In addition, the first covering region 32 may be formed extending uniformly from the junction region 31 to the side surface of the light-emitting element 10, or may be formed discretely and partially hanging down from the junction region 31 to the side surface of the light-emitting element 10.

[0022] This configuration can be easily achieved by surface-treating the region to be exposed from the light-guiding member 30, for example by applying a release agent to the region, thereby making the region less likely to be covered by the light-guiding member 30. A commonly available release agent can be used, such as a fluorine-based release agent, such as Daikin's spray-type Daifree or liquid-type Optool. It is particularly preferable that the surface facing the light-emitting surface of the light-emitting element 10 (the mounting surface) be surface-treated. Furthermore, it is also preferable that a portion of the side surface continuing from the light-emitting surface, particularly the side surface of the semiconductor layer 11, i.e., the exposed surface of the semiconductor layer 11, be surface-treated. Furthermore, this surface treatment does not have to coincide with the covering member 40; they may overlap or be separated from each other.

[0023] On the other hand, in the light emitting device 100 of the example shown in FIGS. 1 and 2, the side surface of the light transmitting member 20 is exposed from the light guiding member 30 and is preferably further covered with a light reflective covering member 40 . In this way, compared to when the light-guiding member 30 also covers the side surfaces of the light-transmitting member 20, the outward bulging of the outer surface of the light-guiding member 30 can be suppressed, thereby shortening the optical path length to the light-transmitting member 20 and improving the optical coupling efficiency. In addition, as described above, this is preferable because it makes it easier to form the first reflecting surface 33 having a shape and inclination angle suitable for reflecting light toward the light-receiving surface 22.

[0024] Next, each component and structure of the light emitting device of the present invention will be described in detail below.

[0025] (light-emitting element) The light-emitting element 10 can be a known element, specifically a semiconductor light-emitting element. GaN-based compound semiconductors are particularly preferred because they can emit short-wavelength visible light or ultraviolet light that can efficiently excite fluorescent materials. Specific emission peak wavelengths are 240 nm to 560 nm, preferably 380 nm to 470 nm. ZnSe-based, InGaAs-based, or AlInGaP-based semiconductor light-emitting elements are also acceptable.

[0026] (Light emitting element structure) 4, the light-emitting element structure 11 made of semiconductor layers is preferably configured with at least a first conductivity type (n-type) layer 2 and a second conductivity type (p-type) layer 3, with an active layer 3 further disposed therebetween. The electrode structure is preferably a same-side electrode structure in which both first conductivity type (negative) and second conductivity type (positive) electrodes 6, 7 are provided on one main surface, but an opposing electrode structure in which electrodes are provided facing each main surface of the semiconductor layer may also be used. Regarding the mounting form of the light-emitting element 10, for example, in the same-side electrode structure, flip-chip mounting is preferred in which the electrode-forming surface is used as the mounting surface and the opposing substrate 1 side is used as the main emission surface, in terms of optical connection between the emission surface and the light-transmitting member 20. Other possible implementations include mounting the electrode-formed surface as the main emission surface and bonding a light-transmitting member to it, face-up mounting, flip-chip mounting on a light-transmitting member with a wiring structure, or connecting the light-transmitting member to a mounting substrate using the above-mentioned opposing electrode structure. Preferred implementations include mounting in which the light-emitting element and the light-transmitting member do not have wiring or electrodes. The growth substrate 1 of the semiconductor layer 11 may be removed if it does not form a light-emitting element structure. Alternatively, a support substrate, such as a conductive substrate or another light-transmitting member or substrate, may be bonded to the semiconductor layer from which the growth substrate has been removed. This support substrate may also include a light-transmitting member 20. Alternatively, the semiconductor layer may be bonded or covered with a light-transmitting member such as glass or resin, and supported. The growth substrate can be removed by peeling, polishing, or laser lift-off (LLO), for example, while the element is mounted or held on a support, device, or submount. Furthermore, the light-emitting element 10 can have a light reflection structure, and specifically, of the two opposing main surfaces of the semiconductor layer 11, the other main surface opposing the light extraction side (emission surface side) is set as the light reflection side (the lower side in FIG. 1), and a light reflection structure can be provided in the semiconductor layer on this light reflection side, in an electrode, etc. Examples of light reflection structures include a structure in which a multilayer film reflection layer is provided in the semiconductor layer, or a structure in which an electrode and reflection layer having a metal film with high light reflectivity such as Ag or Al or a dielectric multilayer film are provided on the semiconductor layer.

[0027] (Nitride semiconductor light emitting device) As an example of a light-emitting device 10, the nitride semiconductor light-emitting device 10 shown in FIG. 4 has an n-type semiconductor layer serving as a first nitride semiconductor layer 2, a light-emitting layer serving as an active layer 3, and a p-type semiconductor layer serving as a second nitride semiconductor layer 4 epitaxially grown in this order on a C-plane sapphire substrate serving as a growth substrate 1. A portion of the n-type layer 2 is exposed to form an n-type pad electrode serving as a first electrode 7, and a light-transmitting conductive layer 5 such as ITO and a p-type pad electrode serving as a second electrode 6 are formed on substantially the entire surface of the p-type layer 4. Furthermore, a protective film 8 is provided to expose the surfaces of the n-type and p-type pad electrodes 6, 7 and to cover the semiconductor layers. Note that the n-type pad electrode 7 may be formed via a light-transmitting conductive layer, as with the p-type. The growth substrate 1 may be an insulating substrate such as C-plane sapphire, R-plane, A-plane, or spinel (MgAl2O4), or a conductive substrate made of a semiconductor such as silicon carbide (6H, 4H, 3C), Si, ZnS, ZnO, GaAs, GaN, or AlN. Examples of nitride semiconductors include those with the general formula In x Al y Ga 1-x-y In addition to N (0≦x, 0≦y, x+y≦1), B, P, and As may also be mixed crystals. The n-type and p-type semiconductor layers 2 and 4 are not particularly limited to single layers or multilayers, and the active layer 3 preferably has a single (SQW) or multiple quantum well (MQW) structure. An example of a blue-emitting device structure 11 is a structure in which, on a sapphire substrate, a nitride semiconductor underlayer such as a buffer layer, e.g., a low-temperature-grown thin-film GaN and GaN layer, are laminated as n-type semiconductor layers, e.g., an Si-doped GaN n-type contact layer and a GaN / InGaN n-type multilayer film layer, followed by an InGaN / GaN MQW active layer, and further, as p-type semiconductor layers, e.g., an Mg-doped InGaN / AlGaN p-type multilayer film layer and an Mg-doped GaN p-type contact layer, are laminated.

[0028] (light-transmitting material) 1 also includes a light-transmitting member 20 that transmits light from the light-emitting element 10. The light-transmitting member 20 is preferably a light converting member having a wavelength converting material that can convert the wavelength of at least a portion of the light passing through it. For example, as in the example, primary light from the light source excites a phosphor serving as a wavelength converting material in the light-transmitting member 20, thereby obtaining secondary light having a wavelength different from that of the primary light, and further mixing the secondary light with the primary light makes it possible to realize emitted light having a desired hue.

[0029] As described above, the light-transmitting member 20 of the first embodiment encapsulates the light-emitting element 10 in a planar view from the surface 21 (light-emitting surface 90). The side surfaces of the light-transmitting member 20 protrude outward from the side surfaces (end surfaces) of the light-emitting element 10. The light-receiving surface 22, which is wider than the light-emitting surface of the light-emitting element 10, is optically connected via a light-guiding member, resulting in low loss. The protrusion length of the side surfaces of the light-transmitting member relative to the side surfaces of the light-emitting element is, for example, 0.25 to 5 times, more specifically, 0.5 to 2 times, the thickness of the light-emitting element. For example, in the light-emitting device of Example 1, the end of the light-transmitting member 20 protrudes by a width of approximately 50 μm. Alternatively, as shown in the third embodiment described below, the side surfaces of the light-transmitting member may be positioned inward from the side surfaces of the light-emitting element, i.e., the light-emitting surface of the light-emitting element may protrude. Alternatively, the light-receiving surface 22 of the light-transmitting member may be smaller than the light-emitting surface of the light-emitting element 10, as in this example. In this configuration, the protruding length is, for example, 0.25 to 5 times, specifically 0.5 to 2 times, the thickness of the light-transmitting member. Narrowing the light-emitting area relative to the light-emitting element increases brightness, uniforms color mixing, and reduces color unevenness. Furthermore, if the side surfaces of the light-transmitting member 20 are positioned substantially flush with the side surfaces of the light-emitting element 10, color unevenness at the outer edge of the light-transmitting member due to insufficient light from the light-emitting element 10 can be suppressed.

[0030] Here, the light-transmitting material that is the base material of the light-transmitting member 20 can be the same material as the covering member 40 described below, and can be, for example, a resin or an inorganic material such as glass. Even when the light-transmitting member does not have a conversion function, it is preferable to use a material similar to that of the light-transmitting member for light conversion, excluding or replacing the phosphor. Furthermore, when the light-transmitting member is plate-shaped as in the embodiment, it is preferable that both surfaces of the surface 21 and the light-receiving surface 22 are substantially flat, and further, that the opposing surfaces are substantially parallel to each other, which increases the efficiency of optical coupling through the light-guiding member of the present invention and facilitates bonding. On the other hand, various shapes or forms, such as a shape having a curved surface entirely or partially, a planar shape such as an uneven surface, and an optical shape such as a lens shape for light collection or dispersion, can also be used. Furthermore, as a wavelength conversion function, in addition to emitting a mixed light of the primary light of the light-emitting element and its converted light (secondary light), the light-emitting device can also mainly emit secondary light converted from the primary light, such as light converted by ultraviolet light from the light-emitting element or a mixed light of multiple converted light.

[0031] The light-transmitting member 20 with wavelength conversion function may be specifically composed of a glass plate with a light-converting member attached thereto; a single crystal, polycrystalline, amorphous, or ceramic body containing phosphor crystals or their phases; a sintered body, aggregate, or porous material of phosphor crystal particles with an appropriate addition of a translucent material; or a material in which a translucent material, such as a translucent resin, is mixed or impregnated into any of these; or a translucent member containing phosphor particles, such as a translucent resin molded body. From the standpoint of heat resistance, the light-transmitting member 20 is preferably composed of an inorganic material rather than an organic material such as resin. Specifically, a translucent inorganic material containing a phosphor is preferred; and reliability is enhanced by using a sintered body of a phosphor and an inorganic substance (binding material, binder), or a sintered body or crystal of a phosphor. When using the YAG phosphor of the embodiment, in addition to YAG single crystals and high-purity sintered bodies, YAG / alumina sintered bodies using alumina (Al2O3) as a binder, and sintered bodies using glass as a binder are preferred from the viewpoint of reliability. Furthermore, by forming the light-transmitting member 20 in a plate shape, coupling efficiency with the emission surface of the planar light-emitting element 10 is improved and alignment to the main surface of the light-transmitting member 20 is easy so that it is approximately parallel. In addition, by making the thickness of the light-transmitting member 20 approximately constant, the amount of wavelength conversion of passing light is approximately uniform, stabilizing the color mixing ratio and suppressing color unevenness in parts of the light-emitting surface 90. Therefore, when multiple light-emitting elements 10 are mounted on a single light-transmitting member 20, there is little unevenness in the distribution of luminance and chromaticity within the light-emitting surface 90 due to the arrangement of the individual light-emitting elements 10, resulting in approximately uniform and high-brightness light emission. The thickness of the light transmitting member 20 having a wavelength conversion function is preferably 10 μm or more and 500 μm or less, and more preferably 50 μm or more and 300 μm or less, in terms of luminous efficiency and chromaticity adjustment.

[0032] The wavelength conversion material can be suitably combined with a blue light emitting element to produce white light. Typical phosphors used in wavelength conversion materials include YAG phosphors (yttrium aluminum garnet) and LAG phosphors (lutetium aluminum garnet) that are bound with cerium in a garnet structure. In particular, when used for a long period of time at high brightness, the (Re1-x Sm x )3(Al 1-y Ga y )5O 12 :Ce (0≦x<1, 0≦y≦1, where Re is at least one element selected from the group consisting of Y, Gd, La, and Lu), etc. are preferred. Phosphors containing at least one element selected from the group consisting of YAG, LAG, BAM, BAM:Mn, (Zn,Cd)Zn:Cu, CCA, SCA, SCESN, SESN, CESN, CASBN, and CaAlSiN3:Eu can also be used. In addition to the light-transmitting member, the wavelength conversion member can also be provided, for example, between the light-transmitting member and the light-emitting element, in the connecting member thereof, or between the light-emitting element and the covering member. Light-transmitting members, wavelength conversion members, and sintered bodies can also be disposed in the light-emitting device. Reddish components can be increased by using nitride-based phosphors that emit yellow to red light, thereby realizing lighting with a high general color rendering index Ra, warm white LEDs, etc. Specifically, by adjusting the amount of phosphors with different chromaticity points on the CIE chromaticity diagram to match the emission wavelength of the light-emitting element, it is possible to emit light at any point on the chromaticity diagram connected between the phosphors and the light-emitting element. In addition, nitride phosphors, oxynitride phosphors, and silicate phosphors that convert near-ultraviolet to visible light into the yellow to red region can be used. For example, L2SiO4:Eu (L is an alkaline earth metal), especially (Sr x Mae 1-x )2SiO4:Eu (Mae is an alkaline earth metal such as Ca or Ba). Nitride phosphors and oxynitride (oxynitride) phosphors include Sr-Ca-Si-N:Eu, Ca-Si-N:Eu, Sr-Si-N:Eu, Sr-Ca-Si-ON:Eu, Ca-Si-ON:Eu, Sr-Si-ON:Eu, etc. Alkaline earth silicon nitride phosphors include those with the general formula LSi2O2N2:Eu and those with the general formula L x Si y N (2 / 3x+4 / 3y) :Eu or L x Si y O z N (2 / 3x+4 / 3y-2 / 3z) :Eu (where L is Sr, Ca, or Sr and Ca).

[0033] (Covering material) As shown in FIG. 1 , the covering member 40 covers a portion of the light-transmitting member 20, specifically, at least a portion of the side surface of the light-transmitting member 20. In the present invention, the covering member hangs down from the element or the like, preventing the formation of a light leakage path. Therefore, it is preferable that the reflectivity of the covering member be higher than that of the substrate and the wiring provided thereon. Furthermore, the base material of the covering member 40 containing a light-reflecting material is preferably a light-transmitting resin material. Silicone resin compositions, modified silicone resin compositions, etc. are preferred. However, light-transmitting insulating resin compositions such as epoxy resin compositions, modified epoxy resin compositions, and acrylic resin compositions can also be used. Furthermore, covering members with excellent weather resistance, such as hybrid resins containing at least one of these resins, can also be used. Furthermore, inorganic materials with excellent light resistance, such as glass and silica gel, can also be used. Furthermore, resin materials can be molded into desired shapes and cover desired areas. In the present invention, the covering member can be formed to cover the surfaces, particularly the side surfaces, of the light-emitting element, light-guiding member, and light-transmitting member of the light source unit. The surface on the light-emitting side can also be formed into a desired shape, and can be a flat surface as shown in the figure, or a concave or convex curved surface. In the first embodiment, silicone resin is used as the covering material from the viewpoint of heat resistance and weather resistance.

[0034] The coating member 40 further comprises at least one light-reflecting material 45 contained in the substrate. The inclusion of the light-reflecting material 45 increases the reflectivity of the coating member 40. The use of low-absorption particles, more preferably, reduces light absorption and loss, resulting in a coating member with light-scattering properties. The light-reflecting material 45 contained in the coating member 40 is at least one oxide selected from the group consisting of Ti, Zr, Nb, Al, and Si, or AlN or MgF, specifically at least one selected from the group consisting of TiO2, ZrO2, Nb2O5, Al2O3, MgF, AlN, and SiO2. The light-reflecting material particles are preferably an oxide selected from the group consisting of Ti, Zr, Nb, and Al, which provides the material with high reflectivity and low absorption and increases the refractive index difference with the substrate, particularly the translucent resin. The covering member 40 can also be formed from a molded body of the above-mentioned light-reflecting material. Specifically, it can be a porous material such as an aggregate or sintered body of the above-mentioned particles. Alternatively, a molded body formed by the sol-gel method is also acceptable. This is preferable because it increases the difference in refractive index between the above-mentioned light-reflecting material and the air in the porous space, thereby enhancing light reflectivity, and because it can be formed from an inorganic material. On the other hand, compared to a covering member having a base material such as the above-mentioned resin, it can be molded into a desired shape, the covering area can be easily controlled, and sealing and airtight performance can be improved. Therefore, in the present invention, a covering member having the above-mentioned base material is preferred. Furthermore, taking into account the characteristics of both covering members, a composite molded body can be formed from both. For example, the outer surface of the porous molded body can be impregnated with resin, and the inner surface facing the light-emitting element can be porous. In this way, the covering member or the enclosure formed therefrom may be connected to the interior and exterior, or may be gas-permeable, as long as it at least prevents light from leaking out.

[0035] In the case of the covering member 40 containing the light-reflecting material 45 in the base material described above, the depth of light leakage varies depending on the content concentration and density of the material. Therefore, it is advisable to adjust the concentration and density appropriately depending on the shape and size of the light-emitting device. For example, when reducing the thickness of a relatively small light-emitting device, it is preferable to use a high concentration of the light-reflecting material 45. On the other hand, the concentration of the light-reflecting material 45 is adjusted appropriately during the manufacturing process, such as preparation of the raw material for the covering member 40, application of the raw material, and molding. The same applies to the porous body described above. For example, in the embodiment, the content concentration of the light-reflecting material 45 is preferably 20 weight percent (wt%) or more and the thickness is preferably 20 μm or more. This allows for high-intensity, highly directional light emission from the light-emitting surface 90, and the appropriate viscosity facilitates the formation of an underfill using the covering member. Furthermore, increasing the concentration of the light-reflecting material can improve the thermal diffusion of the covering member.

[0036] The covering member 40 is formed on at least the side surfaces of the light-transmitting member 20, preferably covering the side surfaces of the light-emitting element. More preferably, the covering member 40 exposes the light-emitting surface of the light source unit including the light-transmitting member and the light-emitting element and covers the rest of the light source unit. This also applies when the light-guiding member 30 is used. This prevents light from leaking from the side surfaces of the light-transmitting member, suppressing relatively high-intensity light from the side surfaces, and, if a light-converting member is included, light with color differences. This improves the directionality of the emitted light and reduces brightness and color unevenness. Furthermore, by covering the side surfaces of each component and element and restricting the light to the light extraction direction, directivity and brightness can be improved. Furthermore, if the light-transmitting member 20 contains a wavelength-converting material, heat generation from this wavelength-converting material is particularly significant, and this can be improved. As long as the side surfaces of the light-transmitting member 20 are covered with the covering member 40 and the surface 21 is exposed, the outer surface shape is not particularly limited. As shown in FIG. 1, the exposed surface may be recessed below the surface 21 of the light-transmitting member. The protruding light-emitting surface 90 prevents light from being blocked by the covering member 40. The covering member 40 may be substantially flush with the light-emitting element 10, providing a desired surface. In the first embodiment, the covering member 40 also covers a portion of the light-receiving surface 22. As shown in the figure, the covering member 40 covers the periphery of the light-emitting element 10, specifically, the area of ​​the light-receiving surface 22 of the light-transmitting member excluding the area facing the light-emitting element 10. With this configuration, as shown in FIG. 2, the light-receiving surface 22 is provided with an optical connection region (bonding region 31) and a covering region that is covered via the light-guiding member (covering regions 32 and 33). Furthermore, the covering region reflects light traveling toward the light-receiving surface 22 of the light-transmitting member toward the light-extraction side, thereby suppressing optical loss of primary light due to light absorption by the substrate 50, etc. As shown in FIGS. 5 and 8, when multiple light-emitting elements 10 are bonded to a single light-transmitting member 20, the covering member 40 is preferably filled in the spaces between the light-emitting elements (second covering regions 34) to cover the spaced regions of the light-receiving surface 22. This configuration can enhance the heat dissipation properties of the spaced apart area with respect to the heat of the light conversion member in the joint area, and is similarly preferable for the protrusion of the light transmitting member and the first covered area 32 as described above.

[0037] (additive material) In addition, the covering member 40 can be appropriately added with a light-reflecting material 45, a light-converting member, a viscosity enhancer, etc., to obtain a light-emitting device with the desired emission color, the color of the member or device surface, such as black for high contrast, and the desired directional characteristics. Similarly, various colorants can be added as filter materials to cut out unwanted wavelengths. The same applies to other members, as well as light-transmitting materials such as light-guiding members, sealing members, and light-transmitting members.

[0038] (light-guiding member) The light-guiding member 30 is used as an adhesive interposed between the light-emitting element 10 and the light-transmitting member 20 to bond the two members together. This light-guiding member is preferably made of a material that is translucent, can guide the light emitted from the light-emitting element 10 to the light-transmitting member, and can optically couple the two members. Examples of materials for this include the resin materials used for the above-mentioned members, such as translucent thermosetting resins such as silicone resins and epoxy resins. Silicone resins are preferred because of their excellent heat and light resistance. Silicone resins are also preferred because of the effectiveness of the fluorine-based mold release agent. Furthermore, dimethyl-based silicone resins offer excellent reliability, such as high-temperature resistance, while phenyl-based silicone resins have a high refractive index, thereby improving the light extraction efficiency from the light-emitting element 10.

[0039] (Mounting board 50) Meanwhile, in the light-emitting device 100 of FIG. 1, the substrate 50 on which the light-emitting element 10 is mounted can have wiring 51 formed on at least its surface for connection to the element's electrodes, and may also have wiring 52 for external connection. The substrate material can be, for example, aluminum nitride (AlN), and can be a single crystal, polycrystalline, sintered substrate, or other material such as ceramics (e.g., alumina), glass, semimetallic or metallic substrates (e.g., silicon), or a laminate or composite thereof. Metallic and ceramic substrates are preferred due to their high heat dissipation properties. The substrate 50 may not have wiring. For example, the element shown in FIG. 4 may be mounted on the growth substrate side and the element's electrodes may be wire-connected to the device's electrodes, or a light-transmitting member may be wired for connection. Furthermore, as in the light-emitting device shown in the figure, the covering member 40 may be provided on the mounting substrate 50, or it may also cover the outer side surface of the mounting substrate 50. Preferably, at least the surface of the mounting substrate 50 is made of a highly reflective material. 1 and 2, the light emitting element 10 is attached onto wiring 51 with a conductive adhesive 60, and is electrically connected to the outside. The conductive adhesive 60 may be solder, Ag paste, Au bumps, or the like.

[0040] (frame, laminated substrate, base material) The light-emitting device 100 shown in FIG. 1 has a frame 55, which serves as a holding member for the covering member 40. The frame 55 can be formed from ceramic, resin, or the like. Alumina, which has high light reflectivity, is preferred, but this is not limited to this as long as a reflective film is formed on the surface. Resin can be used by screen printing or by adhering a molded body to a mounting substrate. Similarly to the covering member 40, it is preferable to increase the reflectivity by using a light-reflective material. Similarly to the additive member, the frame can be colored depending on the purpose. The frame can also be removed after the covering member is filled or molded. The frame can also be formed integrally with the mounting substrate for the light-emitting element, such as a laminated substrate 56 or a device base having a cavity structure made of a substrate or the like.

[0041] (Method of manufacturing a light-emitting device) An example of a manufacturing method for the light-emitting device 100 shown in FIG. 1 is described below. First, bumps 60 are formed on the mounting substrate 50 or the light-emitting element 10, followed by flip-chip mounting. In this example, one LED chip is mounted in a row in an area corresponding to one light-emitting device on the substrate 50 before singulation. Next, a light-guiding member 30 is applied to the emission surface side of the light-emitting element 10 (the back surface of the sapphire substrate or the exposed nitride semiconductor surface if the substrate has been removed using LLO), and a light-transmitting member 20 is laminated on top of it. The resin 30 is then thermally cured and bonded. Next, a resin constituting a covering member 40 is potted into a frame 55 erected around the light-emitting element 10 using a dispenser (liquid constant-rate dispensing device) or the like so as to cover the side surfaces of the light-emitting element 10 and the light-transmitting member 20. The dripped resin 40 creeps up and covers the side surfaces of the light-emitting element 10 and the light-transmitting member 20 due to surface tension, forming an inclined surface that slopes downward from the surface 21 toward the frame 55. The exposed surface of resin 40 may be flattened to be approximately flush with surface 21. After resin 40 is cured, it is diced at predetermined positions and cut into pieces of a desired size to obtain light emitting device 100.

[0042] (Embodiment 2) Fig. 5(a) is a schematic cross-sectional view of a light-emitting device 200 according to embodiment 2 of the present invention, and Fig. 5(b) is a schematic cross-sectional view for explaining the periphery of the light source unit. In the light-emitting device 200, the configuration other than the number of light-emitting elements 10 and the structure of the light-guiding member 30 is substantially the same as in embodiment 1 described above, and therefore the same components are denoted by the same reference numerals and their description will be omitted as appropriate.

[0043] In the light-emitting device of the present invention, there is no particular limitation on the number of light-emitting elements 10 bonded to one light-transmitting member 20. By using a plurality of light-emitting elements 10, rather than a single element as in the first embodiment, the plurality of light-emitting elements 10 can be appropriately arranged according to the size and shape of the light-transmitting member and the light-emitting surface, and to achieve the desired light-emitting characteristics. These light-emitting elements can also be driven individually, which is preferable because it allows for a light-emitting surface with the desired shape and light-emitting characteristics to be obtained. When multiple light-emitting elements 10 are mounted, they are spaced apart at an appropriate distance from each other. This distance can be determined as appropriate taking into account the light distribution characteristics and heat dissipation of the light-emitting device, as well as the mounting accuracy of the light-emitting elements; for example, it is set to within 10% of the dimensions of the light-emitting elements. Alternatively, the plurality of light-emitting elements 10 may be coupled to one another. In this embodiment, two elements are arranged in a row, but this is not limiting and various arrangements are possible, such as a lattice arrangement, or regular or irregular arrangements. Preferably, the elements are arranged at approximately equal intervals to reduce the intensity distribution.

[0044] In the light emitting device 200, a plurality of (two in the figure) light emitting elements 10 are mounted on a mounting substrate 50 at a distance from each other, and a light transmitting member 20 having a light receiving surface 22 large enough to encompass the plurality of light emitting elements 10 is joined onto the light transmitting member 20 via a light guiding member 30. In this light emitting device 200, the frame is laminated on the substrate 50 to form a base 56 having a cavity structure, and a wiring layer 51 for the mounted elements on the upper surface side and a wiring layer 52 for external connection are also provided on the lower surface of the base 56, which is electrically connected thereto.

[0045] In this light-emitting device 200, the bonding region 31 is provided in the opposing region between the light-receiving surface 22 of the light-transmitting member and the emission surface of each light-emitting element 10. The first covering region 32 is provided on the outward-facing side of the light-emitting element 10, which is located on the outer side of the light-receiving surface among the multiple light-emitting elements. It covers the periphery of the light-receiving surface 22 as a protruding surface, and a first reflecting surface 33 is provided on its outer surface, allowing light emitted laterally from the light-emitting element 10 to be reflected and guided toward the light-receiving surface 22 of the light-transmitting member. In this example, although not shown, multiple light-emitting elements are arranged at one end of the light-receiving surface, and a first covering region and a first reflecting surface are each provided on the side surface of the end, but these may be separated for each element. Preferably, the elements are bonded together, sharing a single first covering region and a single first reflecting surface, and are preferably arranged close enough to form such a first covering region and first reflecting surface. In this case, a recess may be provided in the first covering region between the elements.

[0046] Furthermore, when multiple light-emitting elements 10 are bonded to the light-receiving surface 22 side of one light-transmitting member 20, the light-guiding member 30 also hangs down in the gap between adjacent light-emitting elements. That is, the light-guiding member 30 has a second covering region 34 that extends from the bonding region 31 to cover a portion of the opposing side surfaces of adjacent light-emitting elements 10 and a portion of the light-receiving surface 22 sandwiched between the elements. This second covering region 34 is typically provided to connect the opposing side surfaces of adjacent light-emitting elements 10. Furthermore, the outer surface of this second covering region 34 is located closer to the light-transmitting member 20 than the mounting surface of the light-emitting element 10, i.e., the light-guiding member is separated from the mounting substrate, thereby preventing light from being guided to the substrate 50 and leaking and being absorbed. A second reflecting surface 35 that reflects light emitted from the light-emitting elements 10 toward the light-receiving surface 22 is provided on the outer surface of this second covering region 34. Thus, in a light-emitting device in which a plurality of light-emitting elements 10 are mounted on the light-receiving surface 22 of one light-transmitting member 20, the second reflecting surface 35 of the light-guiding member 30 can effectively extract light emitted laterally from the plurality of light-emitting elements 10 and toward the spaced apart regions, and reflect the light toward the light-receiving surface 22 of the light-transmitting member for optical coupling to the light-transmitting member 20. It is also preferable that this second reflecting surface 35 also has an inclined surface similar to the first reflecting surface in the light-emitting device 100 of the first embodiment. In particular, as shown in the figure, a single convex curved surface between the elements is preferable, as this allows the light emitted from each element to be effectively reflected in the spaced apart regions and mixed with each other.

[0047] It is preferable that the second reflecting surface 35 be located farther from the light-receiving surface 22 of the light-transmitting member than the light-emitting surfaces of the light-emitting elements 10. Thus, when the reflecting surface 35 or the tip of the convex curved surface is located closer to the light-receiving surface than the light-emitting surface, as shown in FIG. 8 (Embodiment 5), the emitted light of each light-emitting element 10 can be diffused and guided more widely than when the reflecting surface 35 or the tip of the convex curved surface is located between the light-emitting surface and the light-receiving surface. This reduces the reduction in luminous flux in the spaced apart area, thereby reducing unevenness in brightness and chromaticity due to the arrangement and light distribution of each light-emitting element 10 and achieving uniform brightness within the light-emitting surface. On the other hand, in the former case shown in FIG. 8, although it is easy to separate each light-emitting element and brightness unevenness increases, it is preferable when utilizing the increased light extraction efficiency.

[0048] Furthermore, it is preferable that at least one set of the plurality of light-emitting elements 10 has a different height of the emission surface due to mounting misalignment or the like, and that a light-guiding member be interposed between the sets so that the distances from the emission surfaces of the light-emitting elements to the light-receiving surface 22 of the light-transmitting member are different from one another. This reduces the incidence of light from one light-emitting element 10 to its adjacent light-emitting element 10, and suppresses loss of luminous flux due to light absorption within the light-emitting element 10. This configuration can be adjusted by the thickness of the conductive adhesive 60 that adheres the light-emitting elements 10 to the mounting substrate 50, etc.

[0049] Like the first reflecting surface, the second reflecting surface 35 is preferably provided at the interface between the light-guiding member 30 and the covering member 40 sandwiched between adjacent light-emitting elements 10. In the gap region sandwiched between adjacent light-emitting elements, a metal film such as wiring is often not formed on the mounting substrate 50, leaving the substrate surface exposed, making it prone to light absorption. Therefore, it is preferable that at least the surface of this substrate is covered with a covering member, and it is more preferable that the covering member 40 is filled, and the second reflecting surface 35 is provided at the interface with the covering member 40. Furthermore, as described above, a gap may be provided between the covering member 40 filling the gap region and the second reflecting surface 35.

[0050] (Embodiment 3) FIG. 6 is a schematic cross-sectional view illustrating the periphery of a light source unit of a light-emitting device according to a third embodiment of the present invention. In this light-emitting device, the configuration is the same as that of the first embodiment, except for the size relationship between the light-emitting element 10 and the light-transmitting member 20 and the structure of the light-guiding member 30. Therefore, the same components are denoted by the same reference numerals and will not be described again. In the light-emitting device shown in FIG. 6, the light-receiving surface 22 of the light-transmitting member is smaller than the light-emitting surface of the light-emitting element 10, and a portion of the light-emitting surface protrudes outward from the light-receiving surface 22. In other words, the side surface of the light-transmitting member 20 is located inside the side surface of the light-emitting element 10. This light-emitting device can enhance the brightness of the emitted light by using the light-emitting surface 90 of the light-emitting device as a relatively small light-emitting window. That is, unlike the first and second embodiments, the light-guiding member extends to cover the protruding surface of the light-emitting element and the side surface of the light-transmitting member located inside the protruding end.

[0051] In the light-emitting device of this embodiment, the light-guiding member 30 has a bonding region 31 that bonds the region of the emission surface of the light-emitting element 10 facing the light-transmitting member to the light-receiving surface 22 of the light-transmitting member. The light-guiding member 30 also has a first covering region 32 that extends from the bonding region 31, creeps up onto the side surface of the light-transmitting member 20, and covers the side surface of the light-transmitting member 20. The first covering region 32 that covers the side surface of the light-transmitting member 20 reflects and concentrates the light emitted from the light-emitting element 10, and can particularly reflect light at its end portion and guide it toward the light-transmitting member 20. Furthermore, the outer surface of the first covering region 32 is located closer to the light-transmitting member 20 than the mounting surface of the light-emitting element 10, thereby preventing light from leaking to the mounting substrate 50. Here, the outer surface of the first covered region 32 facing the covering member 40, i.e., the outer surface of the first covered region 32 facing the side surface of the light-transmitting member, has a first reflecting surface 33 that reflects light emitted from the light-emitting element 10 toward the light-transmitting member 20. Therefore, the light transmitted through the first covered region 32 is reflected by the first reflecting surface 33 toward the light-transmitting member 20, and the reflected light is optically coupled to the light-transmitting member 20 and emitted from the light-emitting surface 90 to the outside of the device. In this way, by efficiently optically coupling the light emitted from the light-emitting element 10 toward the light-receiving surface 22 of the light-transmitting member to the light-transmitting member, the utilization efficiency of the light emitted from the light-emitting element 10 can be improved.

[0052] The first reflecting surface 33 in the light-emitting device of this embodiment can have the same interface configuration as the first reflecting surface 33 in the light-emitting device 100 of Embodiments 1 and 2, and similarly, it is preferably provided at the interface with the covering member 40. Furthermore, the outer surface of the first covering region 32 facing the side surface of the light-transmitting member 20 is an inclined surface inclined from the side surface toward the emission surface of the light-emitting element 10, so the first reflecting surface 33 is also an inclined surface that is similarly inclined, which is preferable because it can effectively reflect light toward the light-transmitting member 20. Furthermore, this inclined surface may be flat, but as described above, it is preferable that it be a convex curved surface that is convex toward the bonding region 31, because this increases the surface area of ​​the first reflecting surface 33 and improves the light reflection efficiency.

[0053] On the other hand, in the light-emitting device of the example shown in FIG. 6 , the side surface of the light-emitting element 10 is exposed from the light-guiding member 30 and is preferably covered with a light-reflective covering member 40. In this manner, by providing the outer surface of the light-guiding member 30 so as to connect the emission surface of the light-emitting element 10 to the side surface of the light-transmitting member 20, it is possible to suppress outward bulging of the outer surface of the light-guiding member 30 compared to when the light-guiding member 30 also covers the side surface of the light-emitting element 10. Therefore, the optical path length of light reflected by the outer surface of the light-guiding member 30 to the light-transmitting member 20 can be shortened, reducing light absorption within the light-guiding member 30 and improving the optical coupling efficiency to the light-transmitting member 20. Furthermore, it becomes easier to form the first reflecting surface 33 having a shape and inclination angle suitable for reflecting light toward the light-transmitting member 20, thereby improving the reflection efficiency of the first reflecting surface 33.

[0054] (Fourth embodiment) FIG. 7 is a schematic cross-sectional view illustrating the periphery of a light source unit of a light-emitting device according to a fourth embodiment of the present invention. In the example shown in FIG. 7 , the configuration, except for the shape of the light-guiding member 30 and the surface 21 of the light-transmitting member, is substantially the same as that of the first embodiment described above. Therefore, the same components are denoted by the same reference numerals and will not be described again. In the light-emitting device of the example shown in FIG. 7 , the light-receiving surface 22 of the light-transmitting member is larger than the light-emitting element 10's light-emitting element 10's light-receiving surface 22, and a portion of the light-receiving surface 22 protrudes outward from the light-emitting element 10's light-emitting element 10's light-emitting element 10's light-receiving surface. The light-guiding member 30 has a bonding region 31 that bonds the light-receiving surface 22 of the light-transmitting member 20 to the light-emitting element 10's light-emitting element-facing region. The third covering region 37 extends from the bonding region 31, covers the light-receiving surface 22 of the protruding portion of the light-transmitting member 20, and has an outer surface facing the light-transmitting member 20 relative to the mounting surface of the light-emitting element 10. The side surfaces of the light-emitting element 10 and the light-transmitting member 20 are exposed from the light-guiding member 30. The outer surface of this third covered region 37 has a third reflecting surface 38 that reflects the light emitted from the light-emitting element 10 toward the light-receiving surface 22 of the light-transmitting member 20. Here, the third covered region and the third reflecting surface are one form of the above-mentioned first covered region and first reflecting surface, respectively.

[0055] The outer surface of the third covering region 37 is preferably an inclined surface that slopes from the end of the light-emitting element 10's emission surface toward the light-receiving surface 22 of the protruding portion of the light-transmitting member 20. This allows the third reflecting surface 38 to be an inclined surface that slopes from the end of the light-emitting element 10's emission surface toward the light-receiving surface 22 of the protruding portion of the light-transmitting member 20, thereby effectively reflecting the emitted light from the light-emitting element 10, the reflected light from the light-transmitting member, and the emitted light toward the light-receiving surface 22 of the light-transmitting member. While this inclined surface may be flat, a convex curved surface that is convex toward the bonding region 31 is preferable because it increases the surface area of ​​the third reflecting surface 38 compared to a flat surface, thereby improving the light reflection efficiency. Similarly to the first reflecting surface 33 of the first embodiment, the third reflecting surface 38 is preferably provided at the interface with the covering member 40. However, the third reflecting surface 38 may be separated from the covering member 40 by a gap, or may be formed by providing a metal film or a dielectric multilayer film.

[0056] By bonding the light-emitting element 10 and the light-transmitting member 20 using such a light-guiding member 30, the light emitted from the light-emitting element 10 can be more effectively coupled than when the light-emitting element 10 and the light-transmitting member 20 are bonded only at the bonding region 31, thereby achieving uniform brightness and chromaticity distribution within the light-emitting surface. The light-guiding function of such a light-guiding member 30 depends on the protrusion length of the side surface of the light-emitting element 10 relative to the side surface of the light-transmitting member 20, and therefore, it is preferable to set this length within the above-mentioned range, for example. Such a covering form of the light-guiding member 30 can be achieved by appropriately adjusting the amount, protrusion width, and surface area of ​​the light-guiding member, or by applying a release agent to substantially the entire side surface of the light-emitting element 10 to prevent the light-guiding member 30 from sagging over the side surface of the light-emitting element 10. A release agent may also be applied to the side surface of the light-transmitting member 20, allowing for high-precision manufacturing. In this example, the side surfaces of the light-emitting element are exposed, and the lack of covering, as in the first and second embodiments, reduces the re-entry of returned light and converted light into the element through the light-guiding member. This minimizes the contact area between the light-guiding member and the light-emitting element, improving coupling efficiency. Furthermore, in the example shown in FIG. 7, the surface 23 of the light-transmitting element 20 is textured, which scatters the light passing through the light-transmitting element 20, improving the light extraction efficiency from the light-transmitting element 20, reducing brightness and color variations, and achieving uniform light distribution. This is particularly desirable when multiple light-emitting elements 10 are mounted, as this reduces brightness and color variations. Such texture can be formed on the surface of the light-transmitting element by processes such as polishing, dry etching, and wet etching, and can form irregular as well as regular patterned textures. Furthermore, such an uneven structure can be provided not only on the surface of the light-transmitting member, but also on the light-receiving surface and further on the surface of each member on the optical path to obtain the same effect, and in particular may be provided on the interface with the light-guiding member or the surface of a member in contact with it, for example, the surface of the substrate 1 on the semiconductor layer 11 side, and although not described in detail in the examples, such a structure is used.

[0057] (Variation) In the above-described first to fourth embodiments, the light-emitting element and the light-transmitting member are primarily contained within each other, i.e., are located inside each other. However, the relationship between the light-emitting element and the light-transmitting member in the light-emitting device of the present invention is not limited to this. It is sufficient for one of the light-emitting elements and the light-transmitting member to have at least a partial protrusion that protrudes outward from the other. For example, one of the side surfaces of the light-emitting element, or a portion of one of the side surfaces, may protrude outward from the side surface of the light-transmitting member, while the other side surfaces are substantially flush with each other, or the light-transmitting member may protrude, or vice versa. In such a configuration, a first covering region is provided on the protruding side surface or a portion of the protruding side surface. Furthermore, protrusions may be provided on both sides of either the light-emitting element or the light-transmitting member when viewed from above. In such a configuration, at least one of the first covering regions 32 described in the first and second embodiments is provided in the cross section of the region having the protrusion. Furthermore, when there are multiple light-emitting elements, the first covering region may be provided on the light-emitting element and the light-transmitting member for each element. Preferably, the first covering region is provided on either one of the light-transmitting members, i.e., either of the first and third embodiments, which is preferable from the viewpoint of the functionality of the light-guiding member. Alternatively, some of the side surfaces may be substantially the same. More preferably, the first covering region is uniformly formed between the light-emitting element and the light-transmitting member over the entire outer periphery of the light-transmitting member. This is because it is possible to reduce unevenness in brightness and chromaticity within the light-emitting surface. It is therefore most preferable that one of the side surfaces of the light-emitting element and the light-transmitting member is enclosed within the other.

[0058] As described above, the light-guiding member of the present invention is disposed between the surface of a light-emitting element and a light-transmitting member, optically coupling the two to form a composite light source. The light-guiding member includes a bonding region between the element and the member where they face each other, and a first covering region extending from the bonding region to cover one of the protruding surfaces or the other end face located inside the protruding surface and the other end face. Specifically, the light-guiding member uses a resin material and is also used as an adhesive. As described above, the provision of the protruding surface allows the resin to wet and spread from the bonding region to the surface, and may also wet and spread from the protruding surface to the side surface that forms the other end. Thus, the light-guiding member utilizes the wetting of the resin to each surface during its fabrication, specifically before the resin hardens. Therefore, the amount of the material, the application method, and the protruding width and area of ​​the protruding surface can be controlled first. Additionally, the spread to other regions can be controlled using a release agent. Therefore, as a specific embodiment of the light-guiding member, its thickness in the bonding region is preferably smaller than that of the light-transmitting member and even smaller than that of the growth substrate, thereby reducing the size of the composite light source and improving its coupling efficiency. Furthermore, the protrusion width is preferably approximately 0.25 to 5 times the thickness of the light-emitting element or the light-transmitting member, which facilitates control during manufacturing and allows for suitable diffusion and concentration of light from the element. As described above, when covering the end from one protrusion to the other, as shown in embodiments 1 and 3, it is preferable that the end on the protrusion side is exposed. This is preferable because it reduces the spread of the light source compared to when it is covered, thereby improving the various properties of the present invention. Furthermore, when covering the end, it is preferable for the end to be thinner than the other end to reduce the impact and to be expected to achieve the same effects as the covering member described below.

[0059] As mentioned above, it is preferable to make the covering area of ​​the protruding surface thinner than the bonding area, as shown in Figure 7. However, the effects of the present invention can be expected even if the covering area of ​​the side of the element is thicker by exposing the side of the element through a release treatment. As seen in the first and third embodiments, various characteristics are affected by the covering area of ​​the side of the element. However, when the light-transmitting substrate 1 is made of a different material from the semiconductor layer 11, covering the substrate is preferable because it can serve as a light propagation region between the light-transmitting member and the element, similar to the light-guiding member. In particular, in the case of a light-converting member, the converted light component is also contained in the covering area, which is effective in reducing chromaticity unevenness and light orientation. Furthermore, in an element from which the substrate 1 has been removed, the light component from the exit surface is significantly greater than from the side, so the side of the element may be exposed. As mentioned above, the covering member supports the light-guiding member's functions of light confinement in the composite light source, light emission from the light-emitting surface, and coupling, but a reflective film such as a metal film or a dielectric multilayer film can also be used as a substitute. As in the examples, when a light-reflecting material is included, light seeps into the substrate, causing the light from the light source to spread more widely than inside the coating, thereby improving the efficiency of light diffusion and collection, and further contributing synergistically to the light-emitting characteristics, brightness unevenness, and directivity, particularly to the function of the light-guiding member, which is preferable. Also, in the case of a light-converting member, it is preferable because it contributes favorably to color unevenness and orientation, and further, by coating the side surface, it is preferable because the color and wavelength component ratio differ from those of the surface 21, and the relatively high side light emission can be suppressed.

[0060] Furthermore, the surface of either the light-emitting element 10 or the light-transmitting members 20, 24, whichever has the protruding portion, may not have a clear boundary between the surface facing the other member and the side surface continuing from that surface. For example, in the light-emitting device 100 of the first embodiment, the light-receiving surface 22 and the side surface of the light-transmitting member 20 may be integrated to form a single curved surface, such as a spherical surface or a portion thereof. Furthermore, the light receiving surface 22 of the light transmitting member and the light emitting surface of the light emitting element 10 can be directly bonded by crystal bonding using thermocompression or the like to form a light guiding member 30 having a first covering region on the protruding portion and, if there are multiple light emitting elements, having a second covering region between the elements.

[0061] (Embodiment 5) FIG. 8 is a schematic cross-sectional view of a light-emitting device 300 according to a fifth embodiment of the present invention. In the light-emitting device 300, components substantially similar to those in the first to fourth embodiments are designated by the same reference numerals and will not be described again. In the example shown in FIG. 8, a light-emitting element 10 and a light-transmitting element 20 are covered with a covering element 40 containing a light-reflective material 45 to form a surface-emitting light source in which the surface 21 of the light-transmitting element 20 is the light-emitting surface. A sealing element 80, which serves as a hemispherical optical lens, covers the light source and also partially covers the covering element. In this light-emitting device 300, multiple light-emitting elements 10 (two in the figure) are flip-chip mounted on a wiring pattern 51 on the upper surface of a mounting substrate 50, and one light-transmitting element 20 is bonded thereon via a light-guiding element 30. In this example, the covering element 40 of the frame shown in the first embodiment is removed after molding, and the side surface of the covering element 40 is exposed to the outside, forming the outer surface of the light-emitting device. The cross-sectional width of light-receiving surface 22 of the light-transmitting member is smaller than the distance between the outer side surfaces of light-emitting elements 10 located at the outermost positions, in other words, smaller than the width of the region where multiple light-emitting elements are provided. Furthermore, the side surfaces of light-emitting elements 10 located at the outermost positions protrude outward beyond the side surfaces of light-transmitting member 20. Light-guiding member 30 has a second covering region and second reflecting surface 35 similar to those of embodiment 2 in a spaced region sandwiched between adjacent light-emitting elements, and a first covering region and first reflecting surface 33 similar to those of embodiment 3 in a region connecting the side surfaces of light-transmitting member 20 and the protruding portions of the emission surfaces of light-emitting elements 10 located at the outermost positions.

[0062] According to the configuration of the light-emitting device 300, the first and second covering regions and the first and second reflecting surfaces 33, 35 of the light-guiding member 30 allow the light emitted from the light-emitting element 10 to be efficiently coupled into the light-transmitting member 20, and the light can be efficiently extracted from the light-transmitting member 20 to the sealing member 80, resulting in a higher-output light-emitting device. Furthermore, while the optical lens 80 exaggerates or changes the emitted light depending on the light distribution characteristics at the surface 21 of the light-transmitting member, the light-guiding member 30 of the present invention can homogenize the unevenness in the brightness and chromaticity of the light, resulting in a light-emitting device with excellent light distribution characteristics. Furthermore, the sealing member 80 continuously covers the surface 21 of the light-transmitting member and a portion of the surface of the covering member 40, allowing the light from the sealing member 80 to be reflected by the surface of the covering member 40 and efficiently extracted to the outside. The concave surface of the light-emitting side of the covering member 40, which is inclined from the side of the light-transmitting member 20 toward the substrate 50, diffuses the light, enabling the emitted light of the light-emitting device to be widely distributed. In this way, the light emitting device of the present invention can have desired light emitting characteristics by bonding an optical member to the surface of the light transmitting member on the light emitting surface.

[0063] (Sealing member) Here, if the sealing member 80 has a lower refractive index than the light-transmitting member, bonding with the surface 21 of the light-transmitting member can improve the light extraction efficiency. The light-emitting surface of the sealing member 80 can be formed into various shapes depending on the purpose. For example, as shown in FIG. 8, by making the light-emitting surface a spherical (semispherical) lens shape or a convex curved surface, the light emitted from the light-transmitting member can be extracted to the outside efficiently. Furthermore, without being limited to these, various optical elements and optical members of desired shapes can be used, such as a concave lens shape, a parabolic surface, or a convex shape with a flat tip, and an uneven surface may be used to scatter light.

[0064] The sealing member 80 can be formed using a resin material such as epoxy resin, silicone resin, modified silicone resin, urea resin, urethane resin, acrylic resin, polycarbonate resin, or polyimide resin, similar to the base material of the covering member 30 and the light-guiding member described above. Furthermore, since the sealing member 80 also serves as a sealant to protect the light-emitting element 10 and the light-transmitting member 20, a material with excellent weather resistance, heat resistance, and hardness is preferred. Among the above, epoxy resin or hard silicone resin is preferred. Alternatively, glass may be used. Furthermore, the sealing member 80 can be appropriately added with the above-mentioned phosphor and / or light-scattering particles such as TiO2 and / or fillers such as quartz glass. The sealing member 80 is formed by compression molding, transfer molding, or the like.

[0065] (Embodiment 6) FIG. 9 is a schematic cross-sectional view of a light-emitting device 400 according to a sixth embodiment of the present invention. Components substantially similar to those in the first and second embodiments are designated by the same reference numerals, and their descriptions are omitted where appropriate. In the light-emitting device 400 of the example shown in FIG. 9, a light-emitting element 10 is flip-chip mounted at approximately the center of the bottom of a mounting base (package) 56 having a recess. The mounting portion is part of the mounting base 56, but may also be a submount. A light-transmitting member 24 is placed and bonded to the light-emitting element 10 via a light-guiding member 30. The recess is then filled with a sealing member 84, and the recess is covered with a light-converting member 81 having a surface that becomes a light-emitting surface 82 of the light-emitting device 400. The light-transmitting member 24 and the light-converting member 81 may have the same configuration as the light-transmitting member and the light-transmitting member 20 described above, respectively, when they contain a wavelength conversion material. The sealing member may also have the same configuration as in the fifth embodiment, for example, made of a translucent resin. In particular, in this example, the light-transmitting member 24 may not contain a wavelength converting material. It may be a plate-shaped member as shown, or may be an optical element capable of condensing and diffusing light, or may contain a light-scattering material. Furthermore, a reflective film having a concavely curved surface is provided so as to cover the inner surface of the recess and the side surface of the convex portion of the mounting portion, allowing light to be reflected and condensed toward each of the members 24 and 84. Here, this reflective film is formed by a covering member 41 containing the above-mentioned light-reflective material 46, and the above-mentioned resin creeping forms a concavely curved reflective surface. The covering member 41 may have a highly reflective metal film such as Ag or Al formed on its surface instead of the covering member 41, or may have a light converting member containing the above-mentioned phosphor. Alternatively, the covering member 41 may not have a covering member, and the inner surface of the mounting substrate may be used as a reflective surface as in the conventional case. The recess may contain a light converting member in a sealing member 84, or may be hermetically sealed or filled with the atmosphere. Similarly to member 24, member 81 may not contain a light converting member. That is, a light-emitting device can be made by providing a light-converting member in any of the members 24, 41, 81, and 84 to contain converted light, or a light-emitting device can be made that does not include any of the members and extracts light emitted from the light-emitting element.

[0066] In this light-emitting device 400, as in the second embodiment, the light-guiding member 30 has the bonding region 31, the first covered region, and the first reflecting surface 33. The recess is filled with the sealing member 84, so that the outer surface of the first covered region forms an interface with the translucent sealing member, and the first reflecting surface 33 is provided at that interface. That is, by providing a difference in refractive index between the light-guiding member and the sealing member, the interfacial reflection can be utilized. Making the first covered region have a higher refractive index is preferable because it increases the reflectivity. The same applies to hermetic sealing. Light is emitted from the light-emitting element 10 diffused in all directions, but some of the light components are reflected by the inner surface of the first reflecting surface 33 toward the light-receiving surface 26 of the light-transmitting member 24 and emitted from the light-emitting surface 25. A portion of the light is reflected by the recess and extracted from the light-transmitting member 81. Therefore, the light from the light-emitting element 10 is collected by the light-transmitting member 24 and emitted from the surface 25, increasing the brightness in the front direction, that is, the light-emitting surface 82, and suppressing the diffusion of light within the recess, thereby reducing light absorption. The same applies to the second reflecting surface 35 and its second covering region.

[0067] Furthermore, in the case of the fourth embodiment in which the light emitting element 10 is not covered with the light-reflective covering member 40, it is preferable that the coverage range of the first and second covering regions provided on the side surfaces of the light emitting element 10 be the same as or wider than that of the first embodiment. If the coverage range of the side surfaces of the light emitting element 10 by the light guiding member 30 is wider, the efficiency of extracting light from the light emitting element 10 into the light guiding member 30 can be improved, and the surface areas of the first and second reflecting surfaces 33, 35 can be increased, thereby improving the efficiency of coupling light into the light transmitting member 20. However, as described above, in order to avoid light loss due to light absorption in the mounting base 56, it is preferable that the light guiding member 30 has an outer surface located closer to the light transmitting member 20 than the mounting surface of the light emitting element 10 and is spaced apart from the surface of the mounting base 56.

[0068] Examples of the present invention will be described in detail below. It goes without saying that the present invention is not limited to the examples shown below.

[0069] Example 1 As shown in FIG. 5, the light source section of the light emitting device of Example 1 has two approximately square LED chips of approximately 1 mm × 1 mm (having a structure in which nitride semiconductors 11 are stacked on a sapphire substrate 10 and have an emission wavelength of 455 nm) flip-chip mounted as light emitting elements 10 on wiring 51 of an AlN ceramic substrate 50, and one sintered body of YAG and alumina (Al2O3) placed on top of that as light transmitting member 20, which is a plate-shaped light converting member, and whose surface 21 and light receiving surface 22 have an approximately rectangular shape of approximately 1.1 mm × 2.2 mm and a thickness of approximately 150 μm, and these are joined together by a light guiding member 30. At this time, an appropriate amount of silicone resin that will become light-guiding member 30 is applied with tweezers to the emission surface of each LED (the back surface of substrate 1), and light-transmitting member 20 is placed on top of it with tweezers, hanging down over part of the side surface of light-emitting element 10. The resin is thermally cured in an oven at 150°C for 60 minutes, and the two LEDs are bonded so that they are enclosed within the light-receiving surface of the light-transmitting member as shown. In this way, light-guiding member 30 is formed with bonding region 31 between the LED and light-transmitting member, first covering region 32 that covers the outer side surface of the LED light source, and second covering region 34 that covers the inner side surface between the LEDs. At this time, the light-guiding member is formed on the side surface of the LED, the substrate, and part or almost all of semiconductor layer 11. Then, as shown in FIG. 1, an LED is mounted on wiring 51 of substrate 50, and a cover member 40 is filled into the recess inside the frame surrounding light-emitting element 10 and light-transmitting member 20, so that surface 21 of light-transmitting member 20 is exposed as the light-emitting surface. The light-emitting element 10 and light-transmitting member 20 are encapsulated by cover member 40, and the frame is removed as shown in FIG. 8 to obtain a light-emitting device. Here, cover member 40 is a silicone resin containing a light-reflective material 45, which is TiO2 fine particles with a particle size of approximately 270 nm, at a concentration of approximately 23 weight percent. When driven with a current of 350 mA, the light-emitting device of Example 1 exhibits a luminous flux of approximately 167 [lm] (chromaticity y value of approximately 0.339) and a maximum brightness of 6086 [cd / cm2]. 2 ], average luminance 3524 [cd / cm 2 ], resulting in high luminous flux and brightness.

[0070] Example 2 As shown in Fig. 6, the light-emitting device of Example 2 has a configuration in which the light-receiving surface of one light-transmitting member is enclosed within the emission surface of one light-emitting element. The light-emitting element in Example 1 is a single LED chip 10 having a substantially rectangular shape of approximately 1 mm x 6.5 mm, with six element structures provided on a single sapphire substrate. The light-transmitting member 20 is also a substantially rectangular shape of approximately 0.8 mm x 6.3 mm, and the light-emitting device is fabricated in the same manner as in Example 1. Note that when the light-transmitting member 20 is placed, it is lightly pressed to cause the light-guiding member 30 to creep up onto a portion of the side surface of the light-transmitting member 20, forming a first covering region 32. When driven at a current of 700 mA, the light-emitting device of Example 2 has a luminous flux of approximately 740 [lm] (chromaticity y value of approximately 0.280) and a maximum luminance of 4629 [cd / cm]. 2 ], average luminance 4123 [cd / cm 2 ], resulting in high luminous flux and brightness. [Industrial Applicability]

[0071] The light emitting device of the present invention can be suitably used as a light source for illumination, a backlight source for LED displays, liquid crystal displays, traffic lights, illuminated switches, various sensors, various indicators, and the like. [Explanation of symbols]

[0072] 10...light-emitting element (1...growth substrate, 2...first conductivity type (n-type) semiconductor layer, 3...active layer, 4...second conductivity type (p-type) semiconductor layer, 5...transparent conductive layer, 6...second electrode (p-side pad electrode), 7...first electrode (n-side pad electrode), 8...protective film, 11...element structure) 20, 24... Light-transmitting member (21, 23, 25... surface, 22, 26... light-receiving surface) 30...light guide member (31...bonding region, 32...first covering region, 33...first reflecting surface, 34...second covering region, 35...second reflecting surface, 37...third covering region, 38...third reflecting surface), 40, 41...covering member, 45, 46...light reflecting material 50... Mounting substrate (51, 52... Wiring, 55... Frame, 56... Laminated substrate or base material), 60... Conductive adhesive material

Claims

1. a light emitting element having an emission surface; a light-transmitting member that includes the light-emitting surface and has a light-receiving surface that is disposed opposite the light-emitting surface; a light-guiding member that is disposed in a region where the light-emitting surface of the light-emitting element and the light-receiving surface of the light-transmitting member face each other so as to join the light-emitting surface of the light-emitting element and the light-receiving surface of the light-transmitting member; a substrate having wiring on which the light-emitting element is mounted; a covering member having a light-reflecting material; the light guide member covers a light receiving surface of the light transmitting member located outside the region and a side surface of the light emitting element, and is spaced apart from the surface of the substrate; The covering member covers a side surface of the light-emitting element via the light-guiding member.

2. 2. The light emitting device according to claim 1, wherein the thickness of the region is between 0.01 μm and 100 μm.

3. 3. The light emitting device according to claim 1, further comprising a wavelength converting member that is excited by light emitted from the light emitting element, the wavelength converting member being disposed between the light transmitting member and the light emitting element.

4. the light-transmitting member is a glass plate, The light emitting device according to claim 3 , wherein the wavelength converting member is a light converting member provided on the glass plate.

5. 3. The light emitting device according to claim 1, wherein the light transmitting member is a sintered body of a phosphor and an inorganic material.

6. The light emitting device according to claim 1 , wherein the substrate further comprises a frame surrounding the light emitting element.

7. The light emitting device according to claim 6 , wherein the frame is integrally formed with the substrate.

8. The light emitting device according to claim 1 , wherein the light guide member contains a silicone resin.

9. the covering member includes a resin material, The light emitting device according to claim 1 , wherein the surface of the covering member includes a curved surface that is concave toward the substrate side.

10. The light-emitting device according to claim 9 , wherein the resin material includes a silicone resin.

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