LIGHT EMITTING DEVICE

• US 20090242919A1
• Filed: 03/23/2009
• Published: 10/01/2009
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Lin, Ming-Yao, Lin, Ming-Te, Tai, Kuang-Yu
• Granted Patent: US 7,872,273 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 33/483 Containers
• 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 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting device includes a leadframe, a light emitting unit, a transparent encapsulant, and a fluorescent colloid layer. The light emitting unit is disposed on the leadframe. The transparent encapsulant covers the light emitting unit, wherein the transparent encapsulant has a concave on which at least one reflective surface is disposed. The fluorescent colloid layer is disposed outside the transparent encapsulant, wherein a chamber is formed between the fluorescent colloid layer and the transparent encapsulant. The light generated by the light emitting unit is reflected by the reflective surface and guided to a side wall of the fluorescent colloid layer.

Claims

1. A light emitting device, comprising:

a leadframe,

a light emitting unit disposed on the leadframe;

a transparent encapsulant covering the light emitting unit, wherein the transparent encapsulant has a concave on which at least one reflective surface is disposed; and

a fluorescent colloid layer disposed outside the transparent encapsulant, wherein a chamber is formed between the fluorescent colloid layer and the transparent encapsulant;

wherein the light generated by the light emitting unit is reflected by the reflective surface and guided to a side wall of the fluorescent colloid layer.

2. The light emitting device according to claim 1, wherein the fluorescent colloid layer surrounds the transparent encapsulant.

3. A light emitting device, comprising:

a leadframe;

a light emitting unit disposed on the leadframe;

a non-transparent side element surrounding the light emitting unit;

a transparent encapsulant covering the light emitting unit and located inside the non-transparent side element, wherein an upper surface of the transparent encapsulant has a concave on which a reflective surface is disposed; and

a fluorescent colloid layer disposed at the side wall of the transparent encapsulant and located between the non-transparent side element and the transparent encapsulant;

wherein the light generated by the light emitting unit is reflected by the reflective surface and guided to the side wall of the transparent encapsulant to excite the fluorescent colloid layer and generate a mixed light, the mixed light is then guided to the top of the transparent encapsulant by the non-transparent side element.

4. The light emitting device according to claim 3, wherein the leadframe has two conductive branches electrically connected with the light emitting unit.

5. The light emitting device according to claim 3, further comprising a front light-collecting lens disposed at the top of the transparent encapsulant for controlling light-emitting direction.

6. The light emitting device according to claim 5, wherein the front light-collecting lens is a convex lens.

7. The light emitting device according to claim 5, wherein the cross section of the front light-collecting lens has a plurality of interconnected quarter circles.

8. A light emitting device, comprising:

a leadframe;

a non-transparent carrier disposed under the leadframe;

a light emitting unit disposed on the leadframe;

a transparent encapsulant covering the light emitting unit and disposed on the non-transparent carrier, wherein an upper surface of the transparent encapsulant has a plurality of reflective surfaces; and

a plurality of fluorescent colloid layers disposed at a plurality of side walls of the transparent encapsulant and adjacent to the reflective surfaces;

wherein when the light of the light emitting unit is guided to the fluorescent colloid layers by the reflective surfaces of the transparent encapsulant, the light then excites the fluorescent colloid layers.

9. The light emitting device according to claim 8, wherein the fluorescent colloid layer are vertically disposed on the transparent encapsulant.

10. The light emitting device according to claim 8, further comprising a plurality of non-transparent reflective layers disposed on the reflective surfaces.

11. The light emitting device according to claim 8, wherein the fluorescent colloid layers are embedded into the transparent encapsulant.

12. The light emitting device according to claim 8, wherein the leadframe has a reflective cup in which the light emitting unit is disposed.

13. A light emitting device, comprising:

a leadframe;

a light emitting unit disposed on the leadframe;

a transparent encapsulant covering the light emitting unit and having a reflective surface;

a fluorescent colloid layer disposed on the reflective surface of the transparent encapsulant;

a non-transparent reflective layer covering the fluorescent colloid layer; and

a non-transparent carrier disposed at the bottom side of the leadframe;

wherein the light generated by the light emitting unit is guided to the fluorescent colloid layer by the non-transparent reflective layer for exciting the fluorescent colloid layer, and the light from the fluorescent colloid layer and the light emitting unit is controlled to be outputted from a region restricted by the non-transparent carrier and the non-transparent reflective layer.

14. The light emitting device according to claim 13, wherein the leadframe has a reflective cup in which the light emitting unit is disposed.

15. The light emitting device according to claim 13, wherein the reflective surface has a plurality of segments, the fluorescent colloid layer is disposed on parts of the segments.

16. The light emitting device according to claim 13, further comprising another fluorescent colloid layer disposed between the transparent encapsulant and the non-transparent reflective layer, and at least one transparent spacer layer disposed between the fluorescent colloid layers.

17. The light emitting device according to claim 13, wherein the reflective surface has a curvature.

18. The light emitting device according to claim 13, wherein the non-transparent reflective layer is extended outward from a top edge of the transparent encapsulant.

19. The light emitting device according to claim 13, further comprising a reflector disposed outside the light emitting unit.

20. The light emitting device according to claim 13, wherein the transparent encapsulant has a concave on which the reflective surface is located, the light emitting device further comprises another light emitting unit, the light emitting units are disposed on the leadframe and symmetrically disposed at two sides of a lowest point of the concave.