LIGHT EMITTING DEVICE

• US 20160190418A1
• Filed: 08/08/2014
• Published: 06/30/2016
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: National Institute for Materials Science
• Original Assignee: National Institute for Materials Science, KOHA Company Limited (Tamura Corporation), Tamura Corporation
• Inventors: YOSHIDA, Seitaro, GARCIA VILLORA, Encarnacion Antonia, INOMATA, Daisuke, SANO, Hiroaki, AOKI, Kazuo, SHIMAMURA, Kiyoshi
• Granted Patent: US 9,634,216 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/16315 Shape
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H01L 33/644 : in intimate contact or integrated with parts of the device other than the semiconductor body
• CPC Class Codes: H01L 33/647 : the elements conducting electric current to or from the semiconductor body
• CPC Class Codes: H01S 5/02212 : Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
• CPC Class Codes: H01S 5/02251 : using optical fibres
• CPC Class Codes: H01S 5/32341 : blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/4025 : Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

According to one embodiment of the present invention, the light emitting device includes an LED element, a side wall which surrounds the LED element, a phosphor layer which is fixed to the side wall with an adhesive layer therebetween, and is positioned above the LED element, and a metal pad as a heat dissipating member. The side wall includes an insulating base which surrounds the LED element and a metal layer which is formed on a side surface at the LED element side of the base, and is in contact with the metal pad and the adhesive layer. The adhesive layer includes a resin layer that includes a resin containing particles which have higher thermal conductivity than the resin or a layer that includes solder.

Claims

1. A light-emitting device, comprising:

a light-emitting element that emits a light with a peak wavelength of not more than 480 nm;

a phosphor layer that is operable to convert a wavelength of the light emitted from the light-emitting element; and

a heat dissipating member that dissipates heat generated in the phosphor layer,

wherein the phosphor layer comprises a layer comprising a single crystal phosphor, a ceramic phosphor, a glass including a phosphor particle, a layer comprising a transparent substrate and a phosphor particle-including resin layer formed thereon,

wherein the phosphor layer comprises a layer covering upper and lateral sides of the light-emitting element and being directly connected to the heat dissipating member, or a layer covering the upper side of the light-emitting element and being connected via an adhesive layer to a sidewall surrounding the light-emitting element,

wherein the sidewall comprises a first sidewall or a second sidewall,

wherein the first sidewall comprises an insulating base surrounding the LED element and a metal layer that is formed on a side surface at the LED side of the base and is in contact with the heat dissipating member and the adhesive layer,

wherein the second sidewall comprises a ceramic or a metal in contact with the heat dissipating member and the adhesive layer, and

wherein the adhesive layer comprises a resin layer comprising a resin and a particle having a higher thermal conductivity than the resin, or a layer comprising a solder.

2. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer,

wherein the heat dissipating member comprises a metal pad to be electrically connected to the light-emitting element, and

wherein the sidewall comprises the first sidewall, or the second sidewall comprising the ceramic.

3. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer,

wherein the sidewall comprises the second sidewall comprising the metal, and

wherein the light-emitting element is insulated from the heat dissipating member.

4. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer, and

wherein the heat dissipating member comprises a member comprising a same material as the base of the first sidewall comprising a ceramic and formed integrally with the base of the first sidewall, or a member comprising a same material as the second sidewall and formed integrally with the second sidewall.

5. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer, and

the heat dissipating member comprises a reflector that is in contact with the base of the first sidewall comprising a ceramic or with the second sidewall and has an opening above the light-emitting element.

6. The light-emitting device according to claim 1, wherein the heat dissipating member comprises a heat sink located under the light-emitting element.

7. The light-emitting device according to claim 1, further comprising a light-emitting element-heat dissipating member to dissipate heat of the light-emitting element,

wherein the heat dissipating member is thermally separated from the light-emitting element-heat dissipating member.

8. The light-emitting device according to claim 1, wherein a base material of the transparent substrate comprises glass, gallium oxide, zinc oxide, sapphire, silicon carbide or diamond.

9. The light-emitting device according to claim 1, wherein the transparent substrate has a thermal conductivity of not less than 1 W/(m·

K) and a transmittance of not less than 80% with respect to an emission wavelength of the light-emitting element and a fluorescence wavelength.

10. The light-emitting device according to claim 1, wherein the phosphor particles comprise a particle of a single crystal phosphor.

11. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer, wherein the phosphor layer comprises a metal film on a surface at a portion in contact with the adhesive layer, and

wherein the adhesive layer comprises a solder.

12. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer, and

wherein the phosphor layer comprises a concavo-convex pattern that has a depth of not less than 10% of a thickness of the phosphor layer and is formed on a surface on the light-emitting element side at a portion in contact with the adhesive layer.

13. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer, and

wherein the sidewall is fixed to the heat dissipating member by a screw.

14. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer connected to the sidewall via the adhesive layer, and

wherein the adhesive layer has a thermal conductivity of not less than 3 W/(m·

K).

15. The light-emitting device according to claim 1, wherein the phosphor layer comprises a layer directly connected to the heat dissipating member, and

wherein the light-emitting device further comprises a structure that the lower portion of the phosphor layer is fitted to a groove formed on an upper surface of the heat dissipating member, a structure that a threaded groove formed on a side surface of the groove on the upper surface of the heat dissipating member is screw-fixed to a threaded groove formed on a side surface of the lower portion of the phosphor layer, or a structure that a threaded groove formed on the side surface of the upper portion of the heat dissipating member is screw-fixed to a threaded groove formed on an inner side surface of the lower portion of the phosphor layer.

16. The light-emitting device according to claim 1, wherein a radiation flux density of light emitted from the light-emitting element and incident on the phosphor layer is not less than 1.8 W/cm².

17. The light-emitting device according to claim 1, wherein a rate of an area of the lower surface of the phosphor layer at a portion in contact with the adhesive layer with respect to an area of a region contributing to wavelength conversion is not less than 35%.

18. The light-emitting device according to claim 17, wherein the rate is not less than 70%.

19. The light-emitting device according to claim 1, wherein the phosphor layer is a layer comprising a transparent substrate and a phosphor particle-including resin layer formed thereon, and

wherein a mass concentration of the phosphor particles in the resin layer is not less than 50 mass %.

20. The light-emitting device according to claim 19, wherein the mass concentration is not less than 57 mass %.