LIGHT-EMITTING ELEMENT UNIT AND METHOD OF MANUFACTURING LIGHT-EMITTING ELEMENT UNIT, LIGHT-EMITTING ELEMENT PACKAGE, AND LIGHTING DEVICE

• US 20120162984A1
• Filed: 12/28/2011
• Published: 06/28/2012
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: FUJIMORI, Takao, Nakanishi, Yasuo, Matsui, Nobuaki, Obuchi, Hirotaka
• Granted Patent: US 9,082,945 B2
• Time in Patent Office: Days
• US Class Current: 362/235
• CPC Class Codes: F21V 7/00 Reflectors for light sources characterised by cooling arrangements F21V29/505
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• 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

Abstract

A light emitting element unit according to the present invention includes a semiconductor light emitting element that has a surface, a back surface, and a side surface, where the surface or the back surface is a light extracting surface from which light generated inside is emitted, a submount which has a bottom wall and a side wall, has a recess portion defined by the bottom wall and the side wall, and supports the semiconductor light emitting element by the bottom wall in a position in which the light extracting surface is directed upward at the recess portion, and has an inclined surface on the side wall, inclined at a predetermined angle with respect to the bottom wall so as to face the side surface of the semiconductor light emitting element, and a light reflecting film formed on the inclined surface of the submount.

Claims

1. A light emitting element unit comprising:

a semiconductor light emitting element that has a surface, a back surface, and a side surface, where the surface or the back surface is a light extracting surface from which light generated inside is emitted;

a submount which has a bottom wall and a side wall, has a recess portion defined by the bottom wall and the side wall, and supports the semiconductor light emitting element by the bottom wall in a position in which the light extracting surface is directed upward at the recess portion, and has an inclined surface on the side wall, inclined at a predetermined angle with respect to the bottom wall so as to face the side surface of the semiconductor light emitting element; and

a light reflecting film formed on the inclined surface of the submount.

2. The light emitting element unit according to claim 1, wherein

the submount is formed to have a vessel shape so that the side wall has an annular shape surrounding the bottom wall in a plan view,

the inclined surface is formed to surround the semiconductor light emitting element, and

the light reflecting film is formed along the circumferential direction of the inclined surface.

3. The light emitting element unit according to claim 1, further comprising:

an insulating film formed on the light reflecting film; and

an anode wiring and a cathode wiring which are made of a conductive material capable of reflecting light, and formed on the insulating film so as to lie across the bottom wall, the inclined surface, and a top portion of the side wall of the submount, and whose portions above the bottom wall are electrically connected to an anode and a cathode of the semiconductor light emitting element, respectively.

4. The light emitting element unit according to claim 1, wherein

the light reflecting film is exposed inside the recess portion, and

the light emitting element unit further comprising:

an anode pad and a cathode pad that are made of the same material as that of the light reflecting film, formed on the bottom wall of the submount so as to be separated from the exposed light reflecting film, and electrically connected to the anode and the cathode of the semiconductor light emitting element, respectively.

5. The light emitting element unit according to claim 1, wherein

the submount is formed to have a half-pipe shape concave in a side view, having a pair of the side walls opposed to each other across the bottom wall,

the inclined surface includes a pair of first inclined surface and second inclined surface opposed to each other across the semiconductor light emitting element, and

the light reflecting film includes

an anode side reflecting film that is formed to be exposed inside the recess portion across the bottom wall, the first inclined surface, and the top portion of the side wall of the submount, and includes integrally a first reflecting portion formed on the first inclined surface and an anode connecting portion formed on the bottom wall and electrically connected to the anode of the semiconductor light emitting element, and

a cathode side reflecting film that is formed to be exposed inside the recess portion across the bottom wall, the second inclined surface, and the top portion of the side wall of the submount, includes integrally a second reflecting portion formed on the second inclined surface and a cathode connecting portion formed on the bottom wall and electrically connected to the cathode of the semiconductor light emitting element, and is separated from the anode side reflecting film.

6. The light emitting element unit according to claim 5, wherein

the semiconductor light emitting element is formed to have a rectangular shape in a plan view,

the anode and the cathode are formed adjacent to each other along the longitudinal direction of the semiconductor light emitting element on the semiconductor light emitting element, and

the anode connecting portion and the cathode connecting portion are formed adjacent to each other at a distance from each other along the axial direction of the half-pipe-shaped submount.

7. The light emitting element unit according to claim 1, wherein

the inclined surface is inclined at an angle of 30 to 80 degrees with respect to the bottom wall.

8. The light emitting element unit according to claim 1, wherein

the inclined surface is inclined at an angle of 40 to 70 degrees with respect to the bottom wall.

9. The light emitting element unit according to claim 1, wherein

the inclined surface is inclined at an angle of 45 to 65 degrees with respect to the bottom wall.

10. The light emitting element unit according to claim 1, wherein

the inclined surface is inclined at an angle of 50 to 60 degrees with respect to the bottom wall.

11. The light emitting element unit according to claim 1, wherein the inclined surface is inclined at an angle of 53 to 57 degrees with respect to the bottom wall.

12. The light emitting element unit according to claim 1, further comprising:

a resin phosphor filled in the recess portion.

13. The light emitting element unit according to claim 1, wherein the light reflecting film is made of aluminum.

14. The light emitting element unit according to claim 1, wherein the light reflecting film is made of an alloy containing silver, a platinum group metal, and copper.

15. The light emitting element unit according to claim 14, wherein the platinum group metal is platinum.

16. The light emitting element unit according to claim 14, wherein the platinum group metal is palladium.

17. The light emitting element unit according to claim 1, wherein the back surface of the semiconductor light emitting element is a light extracting surface, and the semiconductor light emitting element is supported by the submount in a face-down position in which the surface is directed downward.

18. The light emitting element unit according to claim 1, wherein the surface of the semiconductor light emitting element is a light extracting surface, and the semiconductor light emitting element is supported by the submount in a face-up position in which the surface is directed upward.

19. A light emitting element package comprising:

a light emitting element unit which includes

a semiconductor light emitting element having a surface, a back surface, and a side surface, where the surface or the back surface is a light extracting surface from which light generated inside is emitted,

a submount which has a bottom wall and a side wall, has a recess portion defined by the bottom wall and the side wall, and supports the semiconductor light emitting element by the bottom wall in a position in which the light extracting surface is directed upward at the recess portion, and has an inclined surface on the side wall, inclined at a predetermined angle with respect to the bottom wall so as to face the side surface of the semiconductor light emitting element, and

a light reflecting film formed on the inclined surface of the submount;

a base substrate supporting the light emitting element unit; and

a resin case that is formed on the base substrate and surrounds the light emitting element unit.

20. An illuminating device comprising:

a long and thin support bar; and

light emitting element units

which are aligned along the longitudinal direction of the support bar, and

each of which includes

a semiconductor light emitting element that has a surface, a back surface, and a side surface, where the surface or the back surface is a light extracting surface from which light generated inside is emitted,

a submount which has a bottom wall and a side wall, has a recess portion defined by the bottom wall and the side wall, and supports the semiconductor light emitting element by the bottom wall in a position in which the light extracting surface is directed upward at the recess portion, and has an inclined surface on the side wall, inclined at a predetermined angle with respect to the bottom wall so as to face the side surface of the semiconductor light emitting element, and

a light reflecting film formed on the inclined surface of the submount.

21. A method for manufacturing a light emitting element unit, comprising the steps of;

forming a recess portion and, simultaneously, an inclined surface inclined at a predetermined angle with respect to a bottom wall that partitions the recess portion from the back surface side, on the recess portion side of a side wall that partitions the recess portion from the lateral side, by selectively wet-etching an Si substrate having a surface and a back surface from the surface side;

forming a light reflecting film on the inclined surface; and

mounting a semiconductor light emitting element which has a surface, a back surface, and a side surface, and whose surface or back surface is a light extracting surface from which light generated inside is emitted, on the bottom wall of the Si substrate so that the light extracting surface faces upward and the side surface faces the inclined surface.

22. The method for manufacturing a light emitting element unit according to claim 21, wherein

the step of forming the recess portion includes a step of forming a first mask annular in a plan view on the surface along the peripheral edge portion of the Si substrate, and

a step of processing the Si substrate into a vessel shape so that the side wall is formed to have an annular shape in a plan view surrounding the bottom wall by wet-etching from the surface of the Si substrate exposed from the first mask.

23. The method for manufacturing a light emitting element unit according to claim 21, wherein

the Si substrate has a tetragonal shape in a plan view, and

the step of forming the recess portion includes

a step of forming a second mask on the surface along peripheral edge portions opposed to each other of the Si substrate, and

a step of processing the Si substrate into a half-pipe shape concave in a side view so that a pair of the side walls are opposed to each other across the bottom wall by wet-etching from the surface of the Si substrate exposed from the second mask.

24. The method for manufacturing a light emitting element unit according to claim 21, wherein

the step of forming the light reflecting film includes

a step of forming a conductive material capable of reflecting light across the bottom wall, the inclined surface, and the top portion of the side wall of the Si substrate, and

a step of forming a first reflecting film across the bottom wall, the inclined surface, and the top portion of the side wall of the Si substrate, and, simultaneously, a second reflecting film separated from the first reflecting film and laid across the bottom wall, the inclined surface, and the top portion of the side wall of the Si substrate by patterning the conductive material on the Si substrate.

25. The method for manufacturing a light emitting element unit according to claim 21, further comprising:

a step of forming an insulating film on the light reflecting film; and

a step of forming simultaneously a first wiring and a second wiring separated from each other by forming a conductive material capable of reflecting light on the insulating film so as to lie across the bottom wall, the inclined surface, and the top portion of the side wall of the Si substrate.

26. The method for manufacturing a light emitting element unit according to claim 21, wherein

the step of forming the light reflecting film includes

a step of forming a conductive material capable of reflecting light across the bottom wall, the inclined surface, and the top portion of the side wall of the Si substrate, and

a step of forming the light reflecting film on the inclined surface, and, simultaneously, a first pad and a second pad separated from the light reflecting film and separated from each other on the bottom wall of the Si substrate by patterning the conductive material on the Si substrate.