Light-emitting devices for liquid crystal displays

• US 8,162,526 B2
• Filed: 06/14/2011
• Issued: 04/24/2012
• Est. Priority Date: 08/23/2005
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Rambus International Ltd (Rambus Inc.)
• Inventors: Erchak, Alexei A., Lim, Michael, Karlicek, Robert F. Jr., Brown, Michael Gregory, Venezia, Jo A.
• Primary Examiner(s): HAN, JASON
• Application Number:
  US13/160,179
• Publication Number:
  US 20110240961A1
• Time in Patent Office: 315 Days
• Field of Search: 362/330, 362/612, 362/615, 362/621, 349/65, 349/69
• US Class Current: 362/612
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01L 2224/49111 the connectors connecting two common bonding areas, e.g. Litz or braid wires
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09

Abstract

Light emitting devices, and related components, processes, systems and methods are disclosed.

Claims

1. A system, comprising:

a panel having an edge, the edge having a thickness defined between a front surface of the panel and a back surface of the panel and having a length measured along the edge in a direction perpendicular to a direction of the thickness, wherein the panel is configured to propagate light therein; and

a light emitting diode (LED) light source comprising a light emitting device die, the light emitting device die having a rectangular upper surface through which light is emitted, the upper surface having a long edge, a short edge, and an aspect ratio of the long edge to the short edge of at least 1.5, the upper surface disposed relative to the edge of the panel such that light emitted through the upper surface impinges on the edge of the panel and enters the panel through the edge; and

wherein the light emitting device die comprises a pattern of openings in at least the upper surface, the pattern of openings creating a dielectric function that varies spatially according to the pattern, the pattern of openings being configured such that the light that is emitted through the upper surface is more collimated than a Lambertian distribution; and

wherein the long edge of the light emitting device die is parallel to the length direction of the edge of the panel, the short edge of the light emitted device die is parallel to a thickness direction of the edge of the panel, and a ratio of a length of the short edge of the LED light source to the thickness of the edge of the panel ranges from 0.5 to 1.1.

2. The system of claim 1, wherein the long edge is at least 1 mm.

3. The system of claim 2, wherein the long edge is at least 2 mm.

4. The system of claim 1, wherein the aspect ratio is at least 1.7.

5. The system of claim 4, wherein the aspect ratio is at least 2.0.

6. The system of claim 1, wherein the short edge to thickness ratio is from about 0.75 to about 1.05.

7. The system of claim 6, wherein the short edge to thickness ratio is about 0.9 to about 1.

8. The system of claim 1, further comprising at least one optical component disposed between the LED light source and the edge of the panel.

9. The system of claim 1, additionally comprising a light homogenizer, the light homogenizer being disposed such that the light emitted through the upper surface impinges thereon and guides the light to the panel.

10. The system of claim 1, wherein the light emitting device die comprises a multi-layer stack of materials including a light generating region and a first layer supported by the light generating region, the upper surface being located on the first layer.

11. The system of claim 10, wherein the light generating region comprises a quantum well.

12. The system of claim 10, wherein the light generating region comprises InGaN/GaN quantum wells.

13. The system of claim 10, wherein the first layer comprises an n-type doped GaN layer.

14. The system of claim 10, wherein the openings extend through the first layer.

15. The system of claim 14, wherein the openings additionally extend through the light generating region.

16. The system of claim 1, wherein the pattern is a periodic pattern with an ideal lattice constant and detuned by a detuning parameter ranging between zero percent and 15 percent.

17. The system of claim 16, wherein the pattern is a modified triangular pattern.

18. The system of claim 1, wherein the pattern is a nonperiodic pattern.

19. The system of claim 1, wherein the pattern is a complex periodic pattern.

20. The system of claim 1, wherein a plurality of light emitting device dies are disposed relative to the edge.

21. The system of claim 20, wherein the light emitting device dies are disposed in a plurality of columns.

22. The system of claim 21, wherein the plurality of columns comprises at least a first column and a second column.

23. The system of claim 22, wherein:

the first column comprises a plurality of light emitting device dies configured to emit a first color of light; and

the second column comprises a plurality of light emitting device dies configured to emit a second color of light, the first and second colors of light being different.

24. The system of claim 23, wherein a third column comprises a plurality of light emitting device dies configured to emit a third color of light, the first, second and third colors of light being different.

25. The system of claim 24, wherein the first, second, and third colors respectively are red, green, and blue.

26. The system of claim 1, further comprising a cooling system configured so that, during use, the cooling system regulates a temperature of the LED light source.

27. The system of claim 1, wherein the light emitting device dies is mounted on a heat sink.

28. The system of claim 1, wherein the light source additionally comprises an encapsulating layer disposed over the upper surface.