Light emitting element

• US 8,294,173 B2
• Filed: 02/12/2008
• Issued: 10/23/2012
• Est. Priority Date: 01/04/2008
• Status: Active Grant

• Current Assignee: Lextar Electronics Corporation
• Original Assignee: Lextar Electronics Corporation
• Inventors: Chen, Wei-An, Fan, Chu-Ping
• Primary Examiner(s): GEBREMARIAM, SAMUEL A
• Application Number:
  US12/068,854
• Publication Number:
  US 20100301357A1
• Time in Patent Office: 1,715 Days
• Field of Search: 257 98-100
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83951 Forming additional members, e.g. for reinforcing, fillet sealant
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

The present invention discloses a light emitting element including a carrier, at least one light emitting chip, an adhesive and a first encapsulated layer. The light emitting chip is fixed onto the carrier by the adhesive, and most of the carrier and adhesive are made of a light absorbing material, so that the external luminescence quantum efficiency of the light emitting element is poor. The invention adopts a first encapsulated layer disposed on the carrier to cover the light absorbing material including the adhesive or carrier, so as to reduce the light absorption and improve the external luminescence quantum efficiency of the light emitting element.

Claims

1. A light emitting element, comprising:

a housing having upwardly extending containing portions;

a separate carrier disposed between the upwardly extending containing portions, wherein the carrier has a top surface defined between the upwardly extending containing portions, wherein the top surface of the carrier comprises a first region, a second region and a third region;

at least one light emitting chip having a light emitting surface, wherein the light emitting chip is installed on the first region of the top surface of the carrier;

an adhesive disposed between the first region of the top surface of the carrier and the light emitting chip; and

a first encapsulating layer disposed on the second region of the top surface of the carrier, without covering the light emitting surface, wherein the third region of the top surface of the carrier is neither covered by the light emitting chip, the adhesive nor the first encapsulating layer.

2. The light emitting element of claim 1, wherein the second encapsulating layer further covers the third region of the top surface of the carrier which is neither covered by the light emitting chip, the adhesive or the first encapsulating layer.

3. The light emitting element of claim 1, wherein the first encapsulating layer does not extend to contact any part of the upwardly extending containing portions.

4. The light emitting element of claim 1, wherein a portion of the adhesive extends beyond the first region into the second region, wherein said portion of the adhesive is not covered by the light emitting chip, and wherein the first encapsulating layer covers the portion of the adhesive not covered by the light emitting chip.

5. The light emitting element of claim 4, wherein the adhesive is a silver adhesive.

6. The light emitting element of claim 1, wherein the first encapsulating layer has a top surface lower than the light emitting surface.

7. The light emitting element of claim 6, further comprising a second encapsulating layer disposed over the first encapsulating layer and the light emitting chip.

8. The light emitting element of claim 1, wherein the first encapsulating layer includes a package material and a medium.

9. The light emitting element of claim 8, wherein the medium is composed of refractive particles, bubbles or reflective particle.

10. The light emitting element of claim 9, wherein the refractive particle has a refractive index of 1.5 to 5.0.

11. The light emitting element of claim 8, wherein the medium has a particle diameter of 20 nm to 5 μ

m.

12. The light emitting element of claim 8, wherein the medium is made of a material selected from the collection of titanium dioxide (TiO₂), zinc oxide (ZnO), aluminum nitride (AlN), aluminum oxide (Al₂O₃) and barium carbonate (BaCO₃).

13. A light emitting element, comprising:

a housing having upwardly extending containing portions;

a separate carrier disposed between the upwardly extending containing portions, wherein the carrier has a top surface defined between the upwardly extending containing portions, wherein the top surface of the carrier comprises a first region, a second region and a third region;

at least one light emitting chip, installed on the first region of the top surface of the carrier;

an adhesive disposed between the first region of the top surface of the carrier and the light emitting chip; and

a first encapsulating layer disposed on the second region of the top surface of the carrier adjacent to the light emitting chip, without covering above the light emitting chip, wherein the third region of the top surface of the carrier is neither covered by the light emitting chip, the adhesive nor the first encapsulating layer.

14. The light emitting element of claim 13, wherein the medium has a particle diameter of 20 nm to 5 μ

m.

15. The light emitting element of claim 13, wherein the medium is made of a material selected from the collection of titanium dioxide (TiO₂), zinc oxide (ZnO), aluminium nitride (AlN), aluminum oxide (Al₂O₃) and barium carbonate (BaCO₃).

16. The light emitting element of claim 13, wherein the first encapsulating layer does not extend to contact any part of the upwardly extending containing portions.

17. The light emitting element of claim 13, wherein a portion of the adhesive extends beyond the first region into the second region, and wherein said portion of the adhesive is not covered by the light emitting chip.

18. The light emitting element of claim 17, wherein the adhesive is made of a light absorbing material, and the first encapsulating layer covers the portion of the adhesive not covered by the light emitting chip.

19. The light emitting element of claim 13, wherein the first encapsulating layer has a top surface lower than the light emitting chip.

20. The light emitting element of claim 19, further comprising a second encapsulating layer disposed over the first encapsulating layer and the light emitting chip.

21. The light emitting element of claim 13, wherein the first encapsulating layer includes a package material and a medium.

22. The light emitting element of claim 21, wherein the medium is composed of refractive particles, bubbles or reflective particle.

23. The light emitting element of claim 22, wherein the refractive particle has a refractive index of 1.5 to 5.0.

24. A light emitting element, comprising:

a housing having upwardly extending containing portions;

a separate carrier disposed between the upwardly extending containing portions, wherein the carrier extends to contact the upwardly extending containing portions and wherein the carrier has a top surface comprising a first region, a second region and a third region;

a light emitting chip supported by the first region of the top surface of the carrier, wherein the light emitting chip has a light emitting surface; and

a first encapsulating layer disposed above the second region of the top surface of the carrier, extending to contact sides of the light emitting chip without covering the light emitting surface.

25. The light emitting element as in claim 24, further comprising an adhesive disposed between the first region of the top surface the carrier and the light emitting chip, wherein a portion of the adhesive extends beyond the first region to the second region, wherein said portion of the adhesive is not covered by the light emitting chip, and wherein the first encapsulating layer covers the portion of the adhesive not covered by the light emitting chip and the first encapsulating layer directs light emitted from the light emitting chip in a direction away from the adhesive.

26. The light emitting element of claim 24, further comprising:

a second encapsulating layer disposed above the first encapsulating layer and the light emitting surface.

27. The light emitting element as in claim 26, wherein the light emitting surface is exposed directly to the second encapsulating layer.

28. The light emitting element as in claim 27, wherein the light emitting surface faces away from the carrier, and the first encapsulating layer has a top surface facing away from the carrier and which is below the light emitting surface, such that the light emitting surface is exposed directly to the second encapsulating layer.

29. The light emitting element as in claim 28, wherein the first encapsulating layer comprises a material that directs light emitted from the light emitting chip in a direction away from the carrier.

30. The light emitting element as in claim 29, further comprising an adhesive disposed between the first region of the top surface the carrier and the light emitting chip, wherein a portion of the adhesive extends beyond the first region to the second region, wherein said portion of the adhesive is not covered by the light emitting chip, and wherein the first encapsulating layer covers the portion of the adhesive not covered by the light emitting chip and the first encapsulating layer directs light emitted from the light emitting chip in a direction away from the adhesive.

31. The light emitting element as in claim 29, wherein the first encapsulating layer directs light emitted from the light emitting chip towards the second encapsulating layer.

32. The light emitting element as in claim 29, wherein the material comprises a light reflecting material.