Light emitting device

• US 20070097692A1
• Filed: 10/30/2006
• Published: 05/03/2007
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Tasumi, Koji, Suehiro, Yoshinobu
• Granted Patent: US 7,878,686 B2
• Time in Patent Office: Days
• US Class Current: 362/294
• 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: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/76 with essentially identical parallel planar fins or blades, e.g. with comb-like cross-section
• 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 29/773 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/83 the elements having apertures, ducts or channels, e.g. heat radiation holes
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: F28F 3/02 Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations F28F3/08 takes precedence
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emitting device has a light source having a light emitting element; and a radiator having plural plate members formed of a thermally-conductive material. The plural plate members are stacked on each other while allowing formation of a space between each other at an end portion thereof. The light source is mounted on a side surface of the plural stacked plate members.

Claims

1. A light emitting device, comprising:

a light source comprising a light emitting diode (LED) element; and

a radiator comprising a plurality of plate members comprising a thermally-conductive material,

wherein the plurality of plate members are stacked on each other while allowing formation of a space between each other at an end portion thereof, and

the light source is mounted on a side surface of the plurality of stacked plate members.

2. The light emitting device according to claim 1, wherein:

the light source comprises the light emitting diode (LED) element mounted on a submount.

3. The light emitting device according to claim 1, wherein:

the light source comprises;

an inorganic substrate mounting the light emitting diode (LED) element thereon and comprising a same thermal expansion coefficient as the light emitting diode (LED) element; and

an inorganic sealing material sealing the light emitting diode (LED) element and comprising a same thermal expansion coefficient as the light emitting diode (LED) element.

4. The light emitting device according to claim 1, wherein:

the radiator comprises the stacked plate members integrated by caulking.

5. The light emitting device according to claim 1, wherein:

the radiator comprises the stacked plate members comprising an edge part formed into a corrugated shape.

6. The light emitting device according to claim 1, wherein:

the light source comprises a wavelength converter to convert a wavelength emitted from the light emitting diode (LED) element.

7. The light emitting device according to claim 1, further comprising:

a casing part surrounding the stacked plate members of the radiator.

9. The light emitting device according to claim 1, wherein:

the reflecting mirror part comprises a paraboloid of revolution with the light source located nearly at a focus thereof while covering the light source.

8. A light emitting device, comprising:

a light source comprising a light emitting diode (LED) element;

a radiator comprising a plurality of plate members comprising a thermally-conductive material, wherein the plurality of plate members are stacked to allow a space between each other at an end portion thereof, and the light source is mounted on a side surface of the radiator; and

a reflecting mirror part to reflect a light emitted from the light source in a direction along a surface of the plate members, and to lead the light to a back surface side of the light source.

10. A light emitting device, comprising:

a light source comprising a light emitting diode (LED) element; and

a radiator comprising a plurality of thermally conductive plates,

wherein the plurality of thermally conductive plates are bonded to each other while allowing at least a part thereof to be separated from each other.

11. The light emitting device according to claim 10, wherein:

the radiator comprises a thermal conductivity of 100 W/m·

K or more.

12. The light emitting device according to claim 10, wherein:

the plurality of thermally conductive plates are directly bonded to the light source.

13. The light emitting device according to claim 10, further comprising:

a thermally conductive member disposed between the light source and the plurality of thermally conductive plates to allow heat transmission from the light source to the plurality of thermally conductive plates.

14. The light emitting device according to claim 10, wherein:

the plurality of thermally conductive plates are folded at a part thereof.

15. The light emitting device according to claim 10, wherein:

the light source further comprises a substrate on which the LED element is mounted, an inorganic sealing material to seal the LED element, and

the LED element and the inorganic sealing material comprise a thermal expansion coefficient of 10×

10<sup>−

6</sup>/°

C. or less.

16. The light emitting device according to claim 10, wherein:

the light source further comprises;

a plurality of the LED elements;

a substrate on which the plurality of the LED elements are mounted; and

a radiation pattern that is formed on an opposite surface to a mounting surface of the substrate, the LED elements being mounted on the mounting surface, and is bonded to the radiator.

17. The light emitting device according to claim 16, wherein:

the radiation pattern is formed by metallizing.

18. The light emitting device according to claim 16, wherein;

the radiation pattern is mounted on the radiator through a material comprising Au and Sn.

19. The light emitting device according to claim 16, wherein:

the substrate comprises a thickness that is smaller than an interval at which the plurality of the LED elements are disposed on the substrate.

20. The light emitting device according to claim 10, wherein:

the light source comprises an area of not more than ten times a total area of the plurality of the LED elements when viewed from a main surface thereof.

21. The light emitting device according to claim 10, further comprising:

an optical system to which a light emitted from the light source is inputted.