JP2019204812A - Light emitting device - Google Patents

Abstract

To provide a light-emitting device capable of providing a brightness difference for each area with a simple configuration.SOLUTION: A light-emitting device 10 includes: a substrate 11; a light-emitting element 12 disposed on the substrate; a wavelength conversion layer 13 formed on the light-emitting element; and a light reflector 14, disposed on the substrate so as to cover a side surface of the light-emitting element, having reflectivity with respect to light emitted from the light-emitting element. The light reflector has a plurality of light reflector units having mutually different thermal conductivity, each of which covers mutually different side surface regions of the light-emitting element.SELECTED DRAWING: Figure 1B

Description

  The present invention relates to a light emitting device including a light emitting element such as a light emitting diode.

  Conventionally, light-emitting elements such as light-emitting diodes and light-emitting devices including the light-emitting elements have been used as various light sources. For example, Patent Document 1 discloses a mounting structure of a light-emitting element having a configuration in which an electrode on a wiring board and an electrode on a light-emitting element are connected by a planar conductive member.

JP 2006-278766 A

  In general, a light emitting device is required to emit high output light, to have a stable output for a long time, and to have a simple configuration. On the other hand, for example, when used as a light source for illumination such as a headlight of a vehicle, it may be preferable that a specific region is irradiated with light having a higher intensity than other regions. In this case, for example, the light emitting device is preferably configured to emit light having different luminance between the specific region and another region.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a light emitting device capable of providing a luminance difference for each region with a simple configuration.

  A light-emitting device according to the present invention includes a substrate, a light-emitting element disposed on the substrate, and a light reflector that is disposed on the substrate so as to cover a side surface of the light-emitting element and has reflectivity with respect to light emitted from the light-emitting element. The light reflector is characterized by having a plurality of light reflector portions each covering different side regions of the light emitting element and having different thermal conductivities.

  In addition, a light emitting device according to the present invention is disposed on a substrate so as to cover each side surface of the substrate, the light emitting element group composed of a plurality of light emitting elements juxtaposed on the substrate, and the light emitting element. A light reflector having reflectivity with respect to light emitted from each of the plurality of light reflectors, each covering a different side region of each of the plurality of light emitting elements, and having a plurality of thermal conductivity It has a light reflector part.

1 is a cross-sectional view of a light emitting device according to Example 1. FIG. 1 is a top view of a light emitting device according to Example 1. FIG. 3 is a diagram illustrating a heat dissipation path in the light emitting device according to Example 1. FIG. FIG. 6 is a diagram showing a light output distribution of the light emitting device according to Example 1. 6 is a top view of a light emitting device according to a first modification of the first embodiment. FIG. 6 is a top view of a light emitting device according to a second modification of the first embodiment. FIG. 6 is a cross-sectional view of a light emitting device according to Modification 3 of Example 1. FIG. FIG. 10 is a top view of a light emitting device according to Modification 3 of Example 1. 6 is a top view of a light emitting device according to Example 2. FIG. 6 is a cross-sectional view of a light emitting device according to Example 2. FIG. 6 is a cross-sectional view of a light emitting device according to Example 2. FIG. 10 is a top view of a light emitting device according to a modification of Example 2. FIG.

  Examples of the present invention will be described in detail below.

  FIG. 1A is a cross-sectional view of the light emitting device 10 according to the first embodiment. FIG. 1B is a schematic top view of the light emitting device 10. 1A is a cross-sectional view taken along line VV in FIG. 1B. For clarity of illustration, a part of FIG. 1B is hatched. The configuration of the light emitting device 10 will be described with reference to FIGS. 1A and 1B.

  The light emitting device 10 includes a substrate 11, a light emitting element 12 formed on the substrate 11, and a wavelength conversion layer 13 formed on the light emitting element 12. In the present embodiment, the substrate 11 is a mounting substrate having a power supply wiring to the light emitting element 12. The light emitting element 12 is mounted on the substrate 11 and connected to the wiring on the substrate 11.

  The light emitting element 12 is, for example, a semiconductor light emitting element such as a light emitting diode. In this embodiment, the light emitting element 12 has a semiconductor layer (not shown) made of a nitride semiconductor. For example, the light emitting element 12 emits light of a light emission color in a blue region (hereinafter sometimes referred to as blue light).

  In the present embodiment, the light emitting element 12 is mounted on the substrate 11. In the light emitting element 12, for example, a semiconductor layer (not shown) including a light emitting layer is formed on the substrate 11 via an electrode (not shown), and a support substrate that supports the semiconductor layer is formed on the semiconductor layer. Has a structured.

  Note that the configuration of the light-emitting element 12 on the substrate 11 is not limited to this. For example, the light emitting element 12 may have a support substrate on the substrate 11 and may have a semiconductor layer on the support substrate. In addition, the light emitting element 12 may include a growth substrate on which a semiconductor layer is grown on the substrate 11 and may have a semiconductor layer on the growth substrate.

  In this embodiment, the light-emitting element 12 is a flat three-dimensional shape having a rectangular (rectangular in this embodiment) top surface when viewed from a direction perpendicular to the mounting surface of the light-emitting element 12 on the substrate 11. The case of having In this embodiment, the upper surface of the light emitting element 12 functions as a light extraction surface of the light emitting element 12.

  The wavelength conversion layer 13 is formed on the upper surface of the light emitting element 12. The wavelength conversion layer 13 is bonded to the upper surface of the light emitting element 12 through an adhesive layer (not shown) that is transparent to the light emitted from the light emitting element 12. The wavelength conversion layer 13 converts the wavelength of part of the light emitted from the light emitting element 12.

  The wavelength conversion layer 13 is made of, for example, a ceramic plate in which aluminum oxide and a phosphor are sintered. The wavelength conversion layer 13 includes, for example, a YAG phosphor, and converts blue light into yellow light (light having a luminescent color in a yellow region). The configuration of the wavelength conversion layer 13 is not limited to this. For example, the wavelength conversion layer 13 may be composed of a resin layer in which phosphor particles are dispersed.

  Further, the upper surface of the wavelength conversion layer 13 functions as a light extraction surface of the light emitting device 10. In the present embodiment, from the upper surface of the wavelength conversion layer 13, light emitted from the light emitting element 12 and converted in wavelength by the wavelength conversion layer 13, and light emitted from the light emitting element 12 and passed through the wavelength conversion layer 13. (Light whose wavelength has not been converted). For example, from the upper surface of the wavelength conversion layer 13, blue light and yellow light are mixed and light that is visually recognized as white light is emitted.

  In this embodiment, the wavelength conversion layer 13 has the same shape as the upper surface of the light emitting element 12, for example, a rectangular shape. The wavelength conversion layer 13 has a flat shape. However, the shape of the wavelength conversion layer 13 is not limited to this, and may have a top surface shape different from the top surface of the light emitting element 12, for example.

  The light emitting device 10 includes a light reflector 14 formed on the substrate 11 so as to cover the side surfaces of the light emitting element 12 and the wavelength conversion layer 13. The light reflector 14 is reflective to the emitted light from the light emitting element 12 and the emitted light from the wavelength conversion layer 13.

  In the present embodiment, the light emitting device 10 includes a frame 15 formed on the substrate 11 so as to surround the light emitting element 12 while being separated from the light emitting element 12. The light reflector 14 is formed in a region outside the light emitting element 12 and the wavelength conversion layer 13 on the substrate 11 and inside the frame 15 surrounded by the frame 15. Note that the upper surface of the wavelength conversion layer 13 is not covered with the light reflector 14 and is exposed to the external atmosphere.

  Further, in the present embodiment, each includes first and second light reflector portions 14H and 14L that respectively cover different side regions of the light emitting element 12 and the wavelength conversion layer 13 and have different thermal conductivities. In the present embodiment, the first light reflector portion 14H has a higher thermal conductivity than the second light reflector portion 14L. In FIG. 1B, the areas of the first and second light reflector portions 14H and 14L are hatched.

  In the present embodiment, the light emitting element 12 includes two long side surfaces (hereinafter, may be referred to as first and second side surfaces in the present embodiment) S11 and S12 and two short side surfaces. (Hereinafter, it may be referred to as the third and fourth sides in this embodiment) S21 and S22. The wavelength conversion layer 13 includes two long side surfaces (hereinafter, sometimes referred to as first and second side surfaces in the present embodiment) S31 and S32 and two short side surfaces (hereinafter referred to as “side surfaces”). S41 and S42, which may be referred to as third and fourth side surfaces in this embodiment).

  In the present embodiment, the first to fourth side surfaces S31, S32, S41, and S42 of the wavelength conversion layer 13 are respectively the first to fourth side surfaces S11, S12, S21, and S22 of the light emitting element 12. It is arranged above. The first to fourth side surfaces S31, S32, S41, and S42 of the wavelength conversion layer 13 extend in parallel with the first to fourth side surfaces S11, S12, S21, and S22 of the light emitting element 12, respectively.

  In the present embodiment, the first light reflector 14H includes the first, third, and fourth side surfaces S11, S21, and S22 of the light emitting element 12, and the first, third, and fourth of the wavelength conversion layer 13. Are formed on the substrate 11 so as to cover the side surfaces S31, S41 and S42. The second light reflector 14L is formed on the substrate 11 so as to cover the second side surface S12 of the light emitting element 12 and the second side surface S32 of the wavelength conversion layer 13.

  In the present embodiment, the light reflector 14 is made of a resin body in which light scatterer particles that scatter the emitted light from the light emitting element 12 and the emitted light from the wavelength conversion layer 13 are dispersed. In the present embodiment, the first and second light reflector portions 14H and 14L include light scatterer particles having different thermal conductivities.

  In the present embodiment, the first light reflector 14H includes titanium oxide particles (first light scatterer particles) P1 and aluminum oxide particles (second second) having higher thermal conductivity than the titanium oxide particles P1. Light scatterer particles) P2. On the other hand, in the present embodiment, the second light reflector portion 14L includes only the titanium oxide particles P1. In the present embodiment, the first and second light reflector portions 14H and 14L include the same resin material, for example, a silicone resin as a base material (dispersion medium).

  The light reflector 14 is, for example, applied and cured on the substrate 11 with a thermosetting resin including titanium oxide particles P1 and aluminum oxide particles P2 to be the first light reflector portion 14H, and then the second light reflection member 14H. It can form by apply | coating the thermosetting resin containing only the titanium oxide particle P1 used as the body part 14L on the board | substrate 11, and making it harden | cure.

  For example, the light emitting device 10 as shown in FIG. 1A can be manufactured as follows. First, a substrate 11 on which wiring (not shown) is formed is prepared. Next, the light emitting element 12 is mounted on the wiring. Subsequently, the wavelength conversion layer 13 is disposed on the light emitting element 12 via an adhesive (not shown), and the wavelength conversion layer 13 is fixed to the light emitting element 12. Then, the frame body 15 is disposed on the substrate 11. Next, a resin body serving as a light reflector 14 (first and second light reflector portions 14H and 14L) is injected so as to fill a region between the frame 15 and the light emitting element 12 and the wavelength conversion layer 13. To cure. In this way, the light emitting device 10 can be manufactured. In addition, it is preferable to adjust the viscosity of the injected resin body so that the shape does not collapse even after the injection.

  FIG. 2A is a diagram schematically illustrating a heat dissipation path in the light emitting device 10. FIG. 2A is a cross-sectional view similar to FIG. 1A, but omits some of the hatching. In the light emitting device 10, heat is generated from the light emitting element 12 and the wavelength conversion layer 13 when conducting to the light emitting element 12. The heat generated in the light emitting element 12 and the wavelength conversion layer 13 is released to the outside of the light emitting device 10 mainly through the substrate 11 and through the light reflector 14 and the substrate 11.

  Here, as described above, the side surfaces of the light emitting element 12 and the wavelength conversion layer 13 are covered with the first and second light reflector portions 14H and 14L having different thermal conductivities. Therefore, the heat dissipation performances near the side surfaces of the light emitting element 12 and the wavelength conversion layer 13 are different from each other.

  Specifically, in the present embodiment, the first side surface S11 of the light emitting element 12 and the first side surface S31 of the wavelength conversion layer 13 have a relatively high thermal conductivity in the light reflector 14. The light reflector 14H is covered. Therefore, the heat H1 generated in the vicinity of the first side surface S11 of the light emitting element 12 and the first side surface S31 of the wavelength conversion layer 13 is transmitted to the first light reflector portion 14H with relatively high efficiency. The

  On the other hand, in the present embodiment, the second side surface S12 of the light emitting element 12 and the second side surface S32 of the wavelength conversion device 13 are the second light having a lower thermal conductivity than the first light reflector 14H. It is covered with the reflector 14L. Accordingly, the heat H2 generated in the vicinity of the second side surface S12 of the light emitting element 12 and the second side surface S32 of the wavelength conversion device 13 is transmitted to the second light reflector portion 14L with relatively low efficiency. The

  Thus, in this example, a relatively large heat dissipation path is formed in the vicinity of the first side surface S11 of the light emitting element 12 and the first side surface S31 of the wavelength conversion layer 13, and the second side surface of the light emitting element 12 is obtained. In the vicinity of S12 and the second side surface S32 of the wavelength conversion layer 13, a relatively small heat dissipation path is formed.

  In general, semiconductor light emitting elements generally tend to exhibit higher light emission efficiency as the junction temperature is lower. In addition, since phosphors used for wavelength conversion and the like cause temperature quenching when the temperature is high, the temperature tends to show higher wavelength conversion efficiency as the temperature is lower.

  Therefore, the region in the vicinity of the first side surface S11 in the light emitting element 12 has higher light emission efficiency and stability by radiating heat more efficiently than the region in the vicinity of the second side surface S12. Moreover, the area | region of the wavelength conversion layer 13 near 1st side surface S31 will have high wavelength conversion efficiency and stability by radiating more efficiently than the area | region of 2nd side surface S32 vicinity.

  Therefore, when the light extraction surface of the light emitting device 10 (the upper surface of the wavelength conversion layer 13 in this embodiment) is viewed, the light emitted from the region near the first side surface S31 of the wavelength conversion layer 13 is wavelength converted. The layer 13 has a higher luminance than the light emitted from the region in the vicinity of the second side surface S32. Also in the region of the wavelength conversion layer 13, a luminance difference is formed so that the luminance gradually decreases from the first side surface S31 toward the second side surface S32.

  FIG. 2B is a diagram illustrating an output of light from the light emitting device 10. FIG. 2B is a diagram illustrating a measurement result of the light output from the wavelength conversion layer 13 between the first and second light reflector portions 14H and 14L. As shown in FIG. 2B, the light output is highest in the vicinity of the first light reflector 14H in the wavelength conversion layer 13, and the output gradually increases toward the vicinity of the second light reflector 14L on the opposite side. You can see that it is getting smaller.

  In order to obtain the result shown in FIG. 2B, the first light reflector portion 14H having a thermal conductivity of about 3.6 W / (m · k) is used, and about 0.2 W / (m · k). The light emitting device 10 was manufactured using the second light reflector 14L having thermal conductivity.

  Thus, in the present embodiment, the inside of the light reflector 14 covering the side surfaces of the light emitting element 12 and the wavelength conversion layer 13 has the first and second light reflector portions 14H and 14L having different thermal conductivities. . Thereby, the light emission efficiency of the light emitting element 12 and the wavelength conversion efficiency of the wavelength conversion layer 13 can be adjusted for each region. Therefore, for example, the light emitting device 10 can provide a luminance difference for each region with a simple configuration without complicating the driving configuration, the element shape, and the like.

  In addition, by providing the light reflector 14 on the side surfaces of the light emitting element 12 and the wavelength conversion layer 13, light traveling from the side surfaces of the light emitting element 12 and the wavelength conversion layer 13 toward the light reflector 14 is applied to the light emitting element 12 and the wavelength conversion layer 13. Can be returned. Therefore, when the light extraction surface is viewed, a clear contrast between the wavelength conversion layer 13 (or the light emitting element 12) and other regions can be provided. Further, light having a certain directivity can be emitted only from the upper surface of the wavelength conversion layer 13 while suppressing light loss.

  In the present embodiment, the light emitting element 12 and the wavelength conversion layer 13 have a rectangular top surface shape. In addition, the first light reflector 14H is provided on the first side surface S11 and S31 which is one of the long side surfaces of the light emitting element 12 and the wavelength conversion layer 13, and the second side surface S12 which is the other side surface. And S32, the second light reflector 14L is provided. Therefore, for example, in the case of forming an elongated light distribution shape, it is possible to provide a luminance difference boundary along the longitudinal direction. When the light-emitting device 10 is used for a vehicle headlamp, a low-luminance region can be associated with a region that illuminates the periphery of the vehicle, and a high-luminance region can be associated with a region that illuminates other distant regions. .

  In this embodiment, the light reflector 14 has first and second light reflector parts 14H and 14L, and the first and second light reflector parts 14H and 14L are different from each other. The case where it consists of a resin body containing was demonstrated. In the present embodiment, the case where the first light reflector portion 14H has the titanium oxide particles P1 and the aluminum oxide particles P2 and the second light reflector portion 14L has the titanium oxide particles P1 has been described. However, the configuration of the light reflector 14 is not limited to this.

  For example, the light reflector 14 may include three or more light reflectors having different thermal conductivities. Further, the first reflector portion 14H may include silicon carbide and aluminum nitride particles in addition to the titanium oxide particles P1 and the aluminum oxide particles P2. Further, the second light reflector portion 14L may include aluminum oxide particles P2. Further, the first and second light reflector portions 14H and 14L may have different resin materials as base materials. The light reflector 14 covers a plurality of light reflectors (for example, the first and second light reflectors 14H, for example) that respectively cover different side regions of the light emitting element 12 and the wavelength conversion layer 13 and have different thermal conductivities. And 14L).

  Moreover, the light emitting element 12 and the wavelength conversion layer 13 do not need to have a side shape having a clear boundary. In this case, for example, the first and second light reflector portions 14H and 14L may cover different side regions in the light emitting element 12 and the wavelength conversion layer 13, respectively.

  In this embodiment, the light reflector 14 is in contact with the substrate 11, and each of the first and second light reflector portions 14 </ b> H and 14 </ b> L is in contact with the substrate 11. Therefore, the overall heat dissipation of the light reflector 14 is ensured by the substrate 11 while providing a difference in heat dissipation performance between the first and second light reflector portions 14H and 14L. Therefore, the light emitting device 10 is a light emitting device that can provide a difference in luminance for each region while having high luminance as a whole.

  In consideration of improving and stabilizing the heat dissipation performance of the light emitting device 10, the substrate 11 and the frame body 15 preferably have a higher thermal conductivity than the light reflector 14. For example, the substrate 11 and the frame body 15 are preferably made of a ceramic material. Note that the light emitting device 10 may not have the frame body 15.

  As described above, in this embodiment, the light emitting device 10 includes the substrate 11, the light emitting element 12 formed on the substrate 11, the wavelength conversion layer 13 formed on the light emitting element 12, the light emitting element 12, and the wavelength. A light reflector 14 is formed on the substrate 11 so as to cover the side surface of the conversion layer 13 and has reflectivity with respect to the light emitted from the light emitting element 12 and the wavelength conversion layer 13. The light reflector 14 includes first and second light reflector portions 14H and 14L that respectively cover different side regions of the light emitting element 12 and the wavelength conversion layer 13 and have different thermal conductivities. Therefore, it is possible to provide the light emitting device 10 that can provide a difference in luminance for each region with a simple configuration.

  FIG. 3A is a schematic top view of the light emitting device 10A according to the first modification of the first embodiment. The light emitting device 10A has the same configuration as the light emitting device 10 except for the configuration of the light reflector 14A. The light reflector 14A includes first and second light reflector parts 14H1 and 14L1 made of the same material as the first and second light reflector parts 14H and 14L of the light reflector 14, respectively.

  In the light reflector 14A, the first reflector portion 14H1 is formed on the substrate 11 so as to cover the first side surface S11 of the light emitting element 12 and the first side surface S31 of the wavelength conversion layer 13. The second light reflector 14L1 covers the second to fourth side surfaces S12, S21, and S22 of the light emitting element 12 and the second to fourth side surfaces S32, S41, and S42 of the wavelength conversion layer 13. , Formed on the substrate 11.

  In the present modification, the region of the first reflector portion 14H1 corresponding to the high luminance portion covers only one side surface (first side surfaces S11 and S31) of the light emitting element 12 and the wavelength conversion layer 13. Thereby, a high-luminance irradiation area can be provided in a line shape.

  FIG. 3B is a schematic top view of the light emitting device 10B according to the second modification of the first embodiment. The light emitting device 10B has the same configuration as that of the light emitting device 10 except for the configuration of the light reflector 14B. The light reflector 14B includes first and second light reflector parts 14H2 and 14L2 made of the same material as the first and second light reflector parts 14H and 14L of the light reflector 14, respectively.

  In the light reflector 14B, the first reflector portion 14H2 is formed on the substrate 11 so as to cover only a part of the first side surface S11 of the light emitting element 12 and the first side surface S31 of the wavelength conversion layer 13. ing. Further, the second light reflector 14L2 is formed on the substrate 11 so as to cover the other side surface of the light emitting element 12.

  In this modification, a high luminance region and a low luminance region can be formed in the side surfaces S11 and S31 of the light emitting element 12 and the wavelength conversion layer 13. Therefore, for example, a high-luminance irradiation region can be provided in a dot shape.

  Like the light emitting devices 10 </ b> A and 10 </ b> B, the first and second light reflector portions 14 </ b> H and 14 </ b> L may cover arbitrary side surfaces of the light emitting element 12 and the wavelength conversion layer 13. This makes it possible to adjust the luminance difference and its area according to various applications.

  FIG. 4A is a cross-sectional view of the light emitting device 10C according to the third modification of the first embodiment. FIG. 4B is a schematic top view of the light emitting device 10C. 4A is a cross-sectional view taken along line WW in FIG. 4B. For clarity of illustration, FIG. 4B is partially hatched.

  The light emitting device 10 </ b> C has the same configuration as the light emitting device 10 except that it does not have the wavelength conversion layer 13 and has a light reflector 14 </ b> C that covers only the side surface of the light emitting element 12. In the light emitting device 10C, the upper surface of the light emitting element 12 is exposed from the light reflector 14C, and the upper surface of the light emitting element 12 functions as a light extraction surface of the light emitting device 10C.

  The light emitting device 10 </ b> C includes a light reflector 14 </ b> C formed on the substrate 11 so as to cover the side surface of the light emitting element 12. The light reflector 14C includes a first light reflector 14H3 formed on the substrate 11 so as to cover the first side surface S11, the third side surface S21, and the fourth side surface S22 of the light emitting element 12. The light reflector 14C includes a second light reflector 14L3 that covers the second side surface S12 of the light emitting element 12 and has a thermal conductivity lower than that of the first light reflector 14H3.

  As shown in the present modification, for example, when the light emitting device 10C does not have the wavelength conversion layer 13 and has a device configuration that emits the emitted light from the light emitting element 12 as it is, the light emitting device 10C includes the light emitting element 12 What is necessary is just to have the light reflector 14C which covers the side surface.

  In this modification, a part of the side surface of the light emitting element 12 is covered with the first light reflector 14H3 having high thermal conductivity, and the other side surface is covered with the second light reflector 14L3 having low thermal conductivity. Covered. Therefore, the luminous efficiency of the light emitting element 12 can be adjusted between the side surfaces by the light reflector 14C, and a luminance difference can be provided between the regions of the light emitting device 10C.

  Also in this modification, the wavelength conversion layer 13 may be provided on the light emitting element 12. Even in this case, by adjusting the luminance only within the light emitting element 12, a difference in luminance can be provided in the extracted light from the light emitting device 10C. In addition, it is possible to variously adjust which side surface region of the light emitting element 12 is covered with the first and second light reflector portions 14H3 and 14L3.

  As described above, in this modification, the light emitting device 10C is formed on the substrate 11 so as to cover the substrate 11, the light emitting element 12 formed on the substrate 11, and the side surface of the light emitting element 12. The light reflector 14 </ b> C has reflectivity with respect to the light emitted from 12. In addition, the light reflector 14C includes a plurality of light reflector portions (first and second light reflector portions 14H3 and 14L3) that each cover different side regions of the light emitting element 12 and have different thermal conductivities. . Therefore, it is possible to provide the light emitting device 10C that can provide a luminance difference for each region with a simple configuration.

  FIG. 5A is a schematic top view of the light emitting device 20 according to the second embodiment. 5B and 5C are cross-sectional views of the light emitting device 20. 5B is a cross-sectional view taken along line X1-X1 in FIG. 5A, and FIG. 5C is a cross-sectional view taken along line X2-X2 in FIG. 5A. For clarity of illustration, a part of FIG. 5A is hatched. The light emitting device 20 will be described with reference to FIGS. 5A to 5C.

  The light emitting device 20 includes a light emitting element group 21 composed of a plurality of light emitting elements 12 juxtaposed on the substrate 11, and a wavelength conversion layer group 22 composed of a plurality of wavelength conversion layers 13 disposed on the upper surface of the light emitting element 12, respectively. Have. The light emitting device 20 is formed on the substrate 11 so as to cover each side surface of the light emitting element 12 and each side surface of the wavelength conversion layer 13, and emits light from each of the light emitting element 12 and the wavelength conversion layer 13. And a light reflector 23 having reflectivity.

  In the present embodiment, similarly to the light reflector 14, the light reflector 23 covers the different side surface regions of the light emitting element 12 and the wavelength conversion layer 13, respectively, and has a first thermal conductivity different from each other. And second light reflectors 23H and 23L. The first and second light reflector parts 23H and 23L are made of the same material as the first and second light reflector parts 14H and 14L of the light reflector 14, respectively.

  In the present embodiment, the light emitting element group 21 includes a plurality of light emitting elements 12 arranged in a matrix. Further, in this embodiment, the light emitting element 12 includes five light emitting elements 12 arranged in one column (for example, corresponding to a matrix of one row and five columns). In the present embodiment, each of the light emitting elements 12 has a flat three-dimensional shape having a square upper surface shape.

  Further, in this embodiment, each of the light emitting elements 12 forms an outer edge on the longitudinal side of the light emitting element group 21 (in the present embodiment, the width direction of the light emitting element group 21), and extends in parallel with each other. (In this embodiment, there are two side surfaces (sometimes referred to as first and second side surfaces) S13 and S14.

  Of the five light-emitting elements 12, one light-emitting element 12 (one in the present example) forms the end of the light-emitting element group 21 on the short side (in the present example, the arrangement direction of the light-emitting element group 21). In addition, each of the two light emitting elements 12) in total is a side surface forming an outer edge on the short side of the light emitting element group 21 (hereinafter, may be referred to as a third side surface and a fourth side surface in this embodiment) S23 and S24. Have

  Each of the light emitting elements 12 has a side surface (hereinafter, may be referred to as a fifth side surface in this embodiment) S5 that faces another adjacent light emitting element 12. Each of the fifth side surfaces S5 in each of the light emitting elements 12 extends in parallel with each other.

  Similarly, in the present embodiment, the wavelength conversion layer group 22 includes a plurality of wavelength conversion layers 13 arranged on the light emitting element 12 and arranged in a matrix. Further, in this embodiment, it is composed of five wavelength conversion layers 13 arranged in one column (for example, corresponding to a matrix of one row and five columns). In the present embodiment, each of the wavelength conversion layers 13 has a flat three-dimensional shape having the same square top surface shape of the light emitting element 12.

  In this embodiment, each of the wavelength conversion layers 13 forms an outer edge on the longitudinal side of the wavelength conversion layer group 22 (in this embodiment, the width direction of the wavelength conversion layer group 22), and extends in parallel with each other. Aligned side surfaces (in this embodiment, two side surfaces (sometimes referred to as first and second side surfaces) S33 and S34 are provided.

  Further, among the five wavelength conversion layers 13, the wavelength conversion layer 13 (in this embodiment) that forms the end of the short side of the wavelength conversion layer group 22 (in the present embodiment, the arrangement direction of the wavelength conversion layer group 22). Each of the two wavelength conversion layers 13 in total is a side surface forming the outer edge on the short side of the wavelength conversion layer group 22 (hereinafter referred to as the third and fourth side surfaces in this embodiment). Have S43 and S44.

  Each of the wavelength conversion layers 13 has a side surface (hereinafter, may be referred to as a fifth side surface in this embodiment) S6 that faces another adjacent wavelength conversion layer 13. Each of the fifth side surfaces S6 in each of the wavelength conversion layers 13 extends in parallel with each other.

  Further, the first to fifth side surfaces S33, S34, S43, S44 and S6 in each of the wavelength conversion layers 13 are respectively the first to fifth side surfaces S13, S14, S23, S24 and It is arranged above S5. Further, the first to fifth side surfaces S33, S34, S43, S44 and S6 in each of the wavelength conversion layers 13 are respectively the first to fifth side surfaces S13, S14, S23, S24 and It extends parallel to S5.

  In the present embodiment, the first light reflector 23H includes the first, third, fourth, and fifth side surfaces S13, S23, S24, and S5 of the side surfaces of the five light emitting elements 12, respectively. Is formed on the substrate 11 so as to cover. The second light reflector 23L is formed on the substrate 11 so as to cover the second side S14 of the side surfaces of the five light emitting elements 12.

  The first light reflector 23H covers each of the first, third, fourth, and fifth side surfaces S33, S43, S44, and S6 among the side surfaces of the five wavelength conversion layers 13. Formed on the substrate 11. The second light reflector 23L is formed on the substrate 11 so as to cover the second side S34 of the side surfaces of the five wavelength conversion layers 13.

  When the plurality of light emitting elements 12 and the wavelength conversion layer 13 are provided as in the light emitting device 20, for example, the respective side surfaces of the light emitting element 12 and the wavelength conversion layer 13 are classified into five types as described above, and these side surfaces are classified into the first type. By selectively covering with the first and second light reflectors 23H and 23L, a difference in luminance can be provided between various regions.

  For example, when the first and second light reflector portions 23H and 23L are arranged as shown in FIG. 5A, only one of the side surfaces forming the outer edges on the long sides of the light emitting element group 21 and the wavelength conversion layer group 22 is supported. The region to be performed can be a low luminance region, and the other region can be a high luminance region.

  Further, for example, by arranging the first light reflector 23H in the region between the adjacent light emitting elements 12, it is possible to suppress the formation of a relatively dark part corresponding to the region between the adjacent light emitting elements 12. The Accordingly, a luminance difference is provided for each region at the outer edge of the light emitting element group 21, while an overall line arrangement is provided such that the luminance difference is small in the region between the adjacent light emitting elements 12 in the light emitting element group 21. A light shape can be obtained. For example, the light emitting device 20 is a light source suitable for a vehicle headlamp, like the light emitting device 10.

  As described above, even when the plurality of light emitting elements 12 and the wavelength conversion layer 13 are provided, the arrangement configuration of the first and second light reflector portions 23H and 23L can be changed. For example, the third and fourth side surfaces S23 and S24 of the light emitting element 12 and the third and fourth side surfaces S43 and S44 of the wavelength conversion layer 13 may be covered with the second light reflector 23L. The fifth side surface S5 of the light emitting element 12 and the fifth side surface S6 of the wavelength conversion layer 13 may be covered with the second light reflector 23L. Also in this embodiment, the wavelength conversion layer group 22 may not be provided. The light reflector 23 may not cover the side surface of the wavelength conversion layer 13 of the wavelength conversion layer group 22.

  In other words, the light emitting device 20 includes the light reflector 23 that is formed on the substrate 11 so as to cover the side surfaces of the plurality of light emitting elements 12 and has reflectivity with respect to the light emitted from the light emitting elements 12. It only has to be. In this case, the light reflector 23 only needs to have first and second light reflector portions 23H and 23L that each cover a different side region of the light emitting element 12 and have different thermal conductivities. .

  Further, for example, the light reflector 23 includes a first light reflector portion 23 </ b> H that covers a side surface region that forms a part of the outer edge region of the light emitting element group 21 among the side surfaces of the light emitting element 12, and the light emitting element group. It is only necessary to cover the side surface region forming the other outer edge region 21 and have the second light reflector 23L having a thermal conductivity smaller than that of the first light reflector 23H.

  Thus, the light emitting device 20 is formed on the substrate 11 so as to cover the substrate 11, the light emitting element group 21 including the plurality of light emitting elements 12 juxtaposed on the substrate 11, and the side surfaces of the plurality of light emitting elements 12. The light reflector 23 is formed and has reflectivity with respect to the light emitted from the light emitting element 12. The light reflector 23 includes first and second light reflector portions 23H and 23L that each cover a different side surface region of the light emitting element 12 and have different thermal conductivities. Therefore, it is possible to provide the light emitting device 20 that can provide a difference in luminance for each region with a simple configuration.

  FIG. 6 is a schematic top view of a light emitting device 20A according to a modification of the second embodiment. The light emitting device 20A has the same configuration as the light emitting device 20 except for the configuration of the light emitting element group 21A, the wavelength conversion layer group 22A, and the light reflector 23A.

  The light emitting device 20A includes a light emitting element group 21A having a plurality of light emitting elements 12 arranged in a matrix in a plurality of rows and a plurality of columns. In this embodiment, the light emitting element group 21A is composed of ten light emitting elements 12 arranged in a matrix of 2 rows and 5 columns.

  Further, the wavelength conversion layer group 22 </ b> A includes a plurality of wavelength conversion layers 13 provided on each of the light emitting elements 12. That is, the light emitting device 20A includes a wavelength conversion layer group 22A having a plurality of wavelength conversion layers 13 arranged in a matrix with a plurality of rows and a plurality of columns. In this embodiment, the wavelength conversion layer group 22A is composed of ten wavelength conversion layers 13 arranged in a matrix of 2 rows and 5 columns.

  In the present embodiment, the light reflector 23A includes the first and second light reflector portions 23H1 made of the same material as the first and second light reflector portions 23H and 23L of the light reflector 23, respectively. And 23L1.

  In the present embodiment, the first reflector portion 23H1 includes each of the side surface region (that is, the fifth side surface) S5 facing the other adjacent light emitting element 12 in each of the light emitting elements 12 and the wavelength conversion layer 13. The side surface region (that is, the fifth side surface) S6 facing the other adjacent wavelength conversion layer 13 is covered. The second reflector portion 23L1 covers the side surface forming the outer edge of the light emitting element group 21A in each of the light emitting elements 12 and the side surface forming the outer edge of the wavelength conversion layer group 22A in each of the wavelength conversion layers 13. .

  In this modification, the region between the adjacent light emitting elements 12 and the region between the adjacent wavelength conversion layers 13 are high luminance regions. In the present modification, the light emitting device 20A is configured to be able to independently switch between conduction and non-conduction of the light emitting elements 12. That is, in the light emitting device 20A, each of the light emitting elements 12 is turned on and off independently.

  The light emitting device 20A is a light source suitable for a headlamp that performs illumination according to the front of the vehicle by dividing the region in front of the vehicle into a plurality of segments and switching between irradiation and non-irradiation for each segment. Specifically, in the case of a light source used for such a vehicle headlamp, it is preferable that light leakage (crosstalk) be small between the light emitting element 12 in a conductive state and the light emitting element 12 in a nonconductive state. On the other hand, it is preferable that the difference in luminance between the two light emitting elements 12 in the conductive state is small. Further, the outer edge portion of the irradiation region may have lower brightness than the central portion, but it is preferable that the light / dark boundary (contrast) is clear.

  In the light emitting device 20A, the first light reflector portion 23H1 having high luminance is disposed in the region between the adjacent light emitting elements 12 (and the region between the adjacent wavelength conversion layers 13), and low in the other regions. A second light reflector portion 23L1 having luminance is disposed. As a result, the luminous efficiency of the light emitting element 12 is increased so as to suppress the formation of dark portions in the side region of the light emitting element 12 between the adjacent light emitting elements 12, and the luminous efficiency is reduced so that the luminance is lower than that in the other side region. Can be intentionally suppressed.

  Therefore, the light-emitting device 20A has a matrix-driven light-emitting element 12 and is a light-emitting device capable of providing a luminance difference for each region suitable for a vehicle headlamp with a simple configuration. In the present embodiment, the case where all the side surfaces of the light emitting element 12 forming the outer edge of the light emitting element group 21A are covered with the second light reflector 23L1 has been described. However, for example, some of the side surfaces of the light emitting element 12 that form the outer edge of the light emitting element 21A may be covered with the first light reflector 23H.

  Also in this modification, the light reflector 23 </ b> A may not cover the side surface of the wavelength conversion layer 13. The light emitting device 20A may not have the wavelength conversion layer group 22A. The light reflector 23A only needs to be formed on the substrate 11 so as to cover each side surface of the light emitting element 12 of the light emitting element group 21A.

  Thus, in the present embodiment, the light emitting element group 21A includes a plurality of light emitting elements 12 arranged in a matrix with a plurality of rows and a plurality of columns. Further, the first light reflector portion 23H1 of the light reflector 23A is formed on the substrate 11 so as to cover a side surface region (fifth side surface S5) facing the other light emitting element 12 adjacent to the light emitting element 12. ing. Accordingly, it is possible to provide the light emitting device 20A capable of providing a luminance difference for each region with a simple configuration.

10, 10A, 10B, 10C, 20, 20A Light emitting device 11 Substrate 12 Light emitting element 13 Wavelength conversion layer 14, 14A, 14B, 14C, 23, 23A Light reflector

Claims (8)

A substrate,
A light emitting device disposed on the substrate;
A light reflector disposed on the substrate so as to cover a side surface of the light emitting element and having reflectivity with respect to light emitted from the light emitting element;
The light reflector includes a plurality of light reflector portions each covering different side regions of the light emitting element and having different thermal conductivities. Each of the plurality of light reflectors is in contact with the substrate,
The light emitting device according to claim 1, wherein the substrate has a thermal conductivity larger than each of the plurality of light reflector portions. Including a wavelength conversion layer formed on the light emitting element,
The light reflector covers a side surface of the wavelength conversion layer,
3. The light emitting device according to claim 1, wherein each of the plurality of light reflectors of the light reflector covers different side regions of the wavelength conversion layer. The light emitting element has a flat three-dimensional shape having a rectangular top surface shape,
The light reflector covers a first light reflector that covers one of the side surfaces on the long side of the light emitting element, and the other of the side surface on the long side of the light emitting element, and the first light reflector The light-emitting device according to claim 1, further comprising: a second light reflector portion having a thermal conductivity smaller than the portion. A substrate,
A light emitting element group comprising a plurality of light emitting elements juxtaposed on the substrate;
A light reflector that is disposed on the substrate so as to cover each side surface of the plurality of light emitting elements and has reflectivity with respect to light emitted from each of the light emitting elements;
The light reflector includes a plurality of light reflector portions each covering a different side surface region of each of the plurality of light emitting elements and having different thermal conductivities.   The light reflector includes a first light reflector portion that covers a side surface region that forms a part of an outer edge region of the light emitting element group among the side surfaces of the plurality of light emitting elements, and the plurality of light emitting elements. A second light reflector having a thermal conductivity smaller than that of the first light reflector, covering a side region forming another outer edge region of the light emitting element group among the side surfaces; The light-emitting device according to claim 5. The light emitting elements of the light emitting element group are arranged in a matrix,
The light reflector includes a first light reflector that covers a side surface region facing the other adjacent light emitting element among the side surfaces of the plurality of light emitting elements, and another one of each of the plurality of light emitting elements. The light-emitting device according to claim 5, further comprising: a second light reflector portion that covers a side surface region and has a thermal conductivity smaller than that of the first light reflector portion. Each has a wavelength conversion layer group consisting of a plurality of wavelength conversion layers disposed on each of the plurality of light emitting elements,
The light reflector covers side surfaces of the plurality of wavelength conversion layers,
8. Each of the plurality of light reflector portions of the light reflector covers a different side surface region of each of the plurality of wavelength conversion layers. 9. Light emitting device.

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