Light emitting device and method of making same

• US 8,309,969 B2
• Filed: 11/20/2009
• Issued: 11/13/2012
• Est. Priority Date: 11/20/2008
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Suehiro, Yoshinobu, Tasumi, Koji
• Primary Examiner(s): GREEN, TELLY D
• Application Number:
  US12/623,135
• Publication Number:
  US 20100123164A1
• Time in Patent Office: 1,089 Days
• Field of Search: 257/79, 257/91, 257/81, 257/99, 362/218, 362/219, 362/294, 362/373
• US Class Current: 257/79
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 29/505 of reflectors
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/763 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/767 the planes containing the fins or blades having directions perpendicular to the light emitting axis
• CPC Class Codes: F21V 5/043 the lens having cylindrical faces, e.g. rod lenses, toric lenses
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: F21V 7/005 with an elongated shape to cooperate with linear light sources
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H05K 1/021 : Components thermally connected to metal substrates or heat-sinks by insert mounting
• CPC Class Codes: H05K 2201/0347 : Overplating, e.g. for reinforcing conductors or bumps; Plating over filled vias
• CPC Class Codes: H05K 2201/0373 : Conductors having a fine structure, e.g. providing a plurality of contact points with a structured tool
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 2201/10969 : Metallic case or integral heatsink of component electrically connected to a pad on PCB
• CPC Class Codes: H05K 3/341 : Surface mounted components

Abstract

A light emitting device includes a light-emitting portion including a metal part including a metal able to be bonded to a solder material, and a heat dissipation member that includes aluminum, aluminum alloy, magnesium or magnesium alloy and a bonding portion processed to be bonded to the solder material. The metal part of the light-emitting portion is bonded via the solder material to the bonding portion of the heat dissipation member. The solder material includes a material unable to be directly bonded to the heat dissipation member, the metal part of the light-emitting portion is formed by metalizing an insulation of ceramic or semiconductor, and the bonding portion includes a thermal expansion coefficient between that of the heat dissipation member and that of the insulation.

Claims

1. A light emitting device, comprising:

a light-emitting portion including a metal part comprising a metal that bonds to a solder material; and

a heat dissipation member that comprises aluminum, an aluminum alloy, magnesium, or a magnesium alloy, and a bonding portion that bonds to the solder material,

wherein the metal part of the light-emitting portion is bonded via the solder material to the bonding portion of the heat dissipation member,

wherein the solder material comprises a material unable to be directly bonded to the heat dissipation member,

wherein the metal part of the light-emitting portion comprises a metalized insulation of a ceramic or a semiconductor, and

wherein the bonding portion has a thermal expansion coefficient between that of the heat dissipation member and that of the metalized insulation.

2. The light emitting device according to claim 1, wherein the heat dissipation member comprises a main body extending from the bonding portion in a predetermined direction, and a plurality of fins integrated with the main body.

3. The light emitting device according to claim 2, wherein the light-emitting portion comprises an LED (light-emitting diode) element, a mount portion of ceramics for mounting the LED element, a sealing portion of an inorganic material for sealing the LED element on the mount portion.

4. The light emitting device according to claim 3, wherein the main body of the heat dissipation member is formed into a plate, the light-emitting portion is mounted on an end face of the main body, and the fins extend from a main surface of the main body.

5. The light emitting device according to claim 3, wherein the heat dissipation member forms a housing comprising an opening for enclosing the light-emitting portion, and

wherein the light emitting device further comprises a phosphor layer at the opening for converting a wavelength of light emitted from the light-emitting portion.

6. The light emitting device according to claim 3, wherein the heat dissipation member further includes a reflecting mirror portion for reflecting light emitted from the light-emitting portion.

7. The light emitting device according to claim 6, wherein the light-emitting portion comprises a plurality of light-emitting portions that form a linear light source while being arranged in a row.

8. The light emitting device according to claim 7, wherein the bonding portion comprises aluminum, an aluminum alloy, magnesium, or a magnesium alloy, and a metal that bonds to the solder material and is dispersed into the aluminum, aluminum alloy, magnesium, or magnesium alloy.

9. A method of producing the light emitting device according to claim 1, said method comprising:

disposing a metal member that bonds to the solder material on a surface of the heat dissipation member that comprises aluminum, an aluminum alloy, magnesium, or magnesium alloy, and is formed by extrusion molding or die casting; and

forming the bonding portion by pressing the metal member while applying ultrasonic wave to an interface between the heat dissipation member and the metal member.

10. The method according to claim 9, wherein the metal member comprises a metal foil, and

wherein the pressing of the metal foil is conducted by using a tool with a concavo-convex surface formed on a contact surface with the metal foil.

11. The method according to claim 9, wherein the bonding portion is formed after the heat dissipation member is previously alumite treated.

12. The light emitting device according to claim 1, wherein the metal part is disposed on an upper surface of the solder material, and

wherein a bottom surface of the solder material, which opposes the upper surface of the solder material, is disposed on a surface of the bonding portion.

13. The light emitting device according to claim 1, wherein opposing surfaces of the solder material abut a bottom surface of the metal part and an upper surface of the bonding portion, respectively.

14. The light emitting device according to claim 1, wherein the bonding portion comprises a metal layer that bonds to the solder material.

15. The light emitting device according to claim 14, wherein a metal of the metal layer is dispersed into the heat dissipation member.

16. A light emitting device, comprising:

a light-emitting portion including a metal part comprising a metal that bonds to a solder material; and

a heat dissipation member that comprises one of aluminum, an aluminum alloy, magnesium, and a magnesium alloy, said heat dissipation member comprising a bonding portion that bonds to the solder material,

wherein the metal part of the light-emitting portion is bonded via the solder material to the bonding portion of the heat dissipation member,

wherein the solder material comprises a material unable to be directly bonded to the heat dissipation member, and

wherein the bonding portion has a thermal expansion coefficient between that of the heat dissipation member and that of the metal part.

17. The light emitting device according to claim 16, wherein the metal part of the light-emitting portion comprises a metalized insulation of a ceramic or a semiconductor.

18. The light emitting device according to claim 16, wherein opposing surfaces of the solder material abut a bottom surface of the metal part and an upper surface of the bonding portion, respectively.

19. The light emitting device according to claim 16, wherein the bonding portion comprises a metal layer that bonds to the solder material, a metal of the metal layer being dispersed into the heat dissipation member.