High power AllnGaN based multi-chip light emitting diode

• US 6,869,812 B1
• Filed: 05/13/2003
• Issued: 03/22/2005
• Est. Priority Date: 05/13/2003
• Status: Expired due to Term

• Current Assignee: BX LED LLC (Ni, Wang & Massand, PLLC)
• Original Assignee: Bridgelux Incorporated
• Inventors: Liu, Heng
• Primary Examiner(s): Lebentritt, Michael
• Application Number:
  US10/438,108
• Time in Patent Office: 679 Days
• Field of Search: 438/22, 438/46, 438/99, 438/127, 438/45, 438/15, 438/16, 438/946, 257 94- 98, 257101-103, 257/201, 257/613
• US Class Current: 438/22
• CPC Class Codes: F21L 4/027 the light sources being a LED
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• 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 2924/00014 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 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting diode chip having a substantially transparent substrate and having an aspect ratio which defines an elongated geometry provides enhanced efficiency and brightness. Method for forming and operating the same are also disclosed.

Claims

1. A light emitting diode chip comprising:

a substantially transparent substrate;

an active region formed upon the substrate; and

wherein an aspect ratio of the active area is greater than approximately 1.5 to 1.

2. The device as recited in claim 1, wherein the aspect ratio of the active area is greater than approximately 2 to 1.

3. The device as recited in claim 1, wherein the aspect ratio of the active area is between approximately 1.5 to 1 and approximately 10 to 1.

4. The device as recited in claim 1, wherein the aspect ratio of the active area is approximately 4 to 1.

5. The device as recited in claim 1, wherein the width thereof is approximately 250 microns and the length thereof is approximately 1000 microns.

6. The device as recited in claim 1, wherein the active region is configured to operate at between approximately 3.0 volts and approximately 3.5 volts and between approximately 60 milliamps and approximately 90 milliamps.

7. The device as recited in claim 1, wherein one light emitting diode device is formed upon the substrate.

8. The device as recited in claim 1, wherein the active area substantially covers a surface of the substrate.

9. The device as recited in claim 1, wherein the substrate comprises a material selected from the group comprising:

sapphire;

spinel;

ZnO;

SiC;

MgO;

GaN;

AlN; and

AlGaN.

10. The device as recited in claim 1, wherein the active region comprises AlInGaN.

11. The device as recited in claim 1, further comprising:

an upper LED layer and a lower LED layer cooperating to define the active region;

an upper contact finger formed upon the upper LED layer;

a lower contact finger formed upon the lower LED layer; and

a reflector disposed intermediate the active region and the lower contact finger, the reflector being configured to reflect light directed from the active region toward the lower contact finger away from the lower contact finger so as to enhance a brightness of the light emitting diode chip.

12. The device as recited in claim 1, further comprising:

an upper LED layer and a lower LED layer cooperating to define the active region;

an upper contact finger formed upon the upper LED layer;

a lower contact finger formed upon the lower LED layer; and

a reflector formed upon the active region intermediate the active region and the lower contact finger, the reflector being configured to reflect light directed from the active region toward the lower contact finger away from the lower contact finger so as to enhance a brightness of the light emitting diode chip.

13. The device as recited in claim 1, further comprising:

an upper LED layer and a lower LED layer cooperating to define the active region;

an upper contact finger formed upon the upper LED layer;

a lower contact finger formed upon the lower LED layer;

a transparent insulator formed upon the active region intermediate the active region and the lower contact finger; and

a reflector formed upon the transparent insulator, the reflector being configured to reflect light directed from the active region toward the lower contact finger away from the lower contact finger so as to enhance a brightness of the light emitting diode chip.

14. The device as recited in claim 1, further comprising:

an upper LED layer and a lower LED layer cooperating to define the active region;

an upper contact finger formed upon the upper LED layer;

a lower contact finger formed upon the lower LED layer; and

a reflector formed upon the active region intermediate the active region and the lower contact finger, the reflector being configured to reflect light directed from the active region toward the lower contact finger away from the lower contact finger so as to enhance a brightness of the light emitting diode chip and the reflector being formed of a dielectric.

15. The device as recited in claim 1, further comprising:

an upper LED layer and a lower LED layer cooperating to define the active region;

an upper contact finger formed upon the upper LED layer;

a lower contact finger formed upon the lower LED layer;

a transparent insulator formed upon the active region intermediate the active region and the lower contact finger; and

a reflector formed upon the transparent insulator, the reflector being configured to reflect light directed from the active region toward the lower contact finger away from the lower contact finger so as to enhance a brightness of the light emitting diode chip and the reflector being formed of a metal.

16. A light emitting diode chip comprising:

a substantially transparent substrate;

an active region formed upon the substrate;

an upper LED layer and a lower LED layer cooperating to define the active region;

an upper contact finger formed upon the upper LED layer;

a lower contact finger formed upon the lower LED layer; and

a reflector disposed intermediate the active region and the lower contact finger, the reflector being configured to reflect light directed from the active region toward the lower contact finger away from the lower contact finger so as to enhance a brightness of the light emitting diode chip.

17. A light emitting diode lamp comprising:

a package;

at least one light emitting diode chip disposed within the package, the light emitting diode(s) comprising;

a substantially transparent substrate;

an active region formed upon the substrate; and

wherein an aspect ratio of the active area is greater than approximately 1.5 to 1.

18. The light emitting diode lamp as recited in claim 17, wherein the package comprises four reflective sides and a reflective bottom.

19. The light emitting diode lamp as recited in claim 17, wherein the package defines a rectangle.

20. The light emitting diode lamp as recited in claim 17, wherein the package defines a square.

21. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise a plurality of light emitting diode chips.

22. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise a plurality of light emitting diode chips which are electrically in series with one another.

23. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise a plurality of light emitting diode chips which are electrically in parallel with one another.

24. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise a plurality of light emitting diode chips which are electrically in a combination of series and parallel with one another.

25. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise four light emitting diode chips.

26. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise four light emitting diode chips configured to generally define a square.

27. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise four light emitting diode chips configured to generally define a linear array thereof.

28. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise four light emitting diode chips which are electrically in series with one another.

29. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise four light emitting diode chips which are electrically in parallel with one another.

30. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprise four light emitting diode chips, which are electrically in a combination of series and parallel with one another.

31. The light emitting diode lamp as recited in claim 17, wherein the light emitting diode chip(s) comprises a plurality of light emitting diode chips which are in electrical communication with one another so as to define a network such that voltage within the network tends to be maximized without current through any light emitting diode chip being greater than a predetermined value.

32. The light emitting diode lamp as recited in claim 17, wherein the package comprises a recessed package having at least one recess with a reflective coating therein, the light emitting diode(s) being disposed within the recess.

33. The light emitting diode lamp as recited in claim 17, wherein the package comprises a recessed package having a plurality of recesses, each recess having a reflective coating therein, at least one light emitting diode being disposed within each recess.

34. The light emitting diode lamp as recited in claim 17, wherein the package comprises a recessed package having four recesses, each recess having a reflective coating therein, one light emitting diode being disposed within each recess.

35. The light emitting diode lamp as recited in claim 17, wherein the package comprises a recessed package having four elongated recesses, each elongated recess having a reflective coating therein, one light emitting diode being disposed within each elongated recess.

36. An illumination device comprising:

a power source;

a light emitting diode lamp in electrical communication with the power source, the light emitting diode lamp comprising;

a package;

at least one light emitting diode chip disposed within the package, the light emitting diode(s) comprising;

a substantially transparent substrate;

an active region formed upon the substrate; and

wherein an aspect ratio of the active area is greater than approximately 1.5 to 1.

37. The illumination device as recited in claim 36, wherein the power source comprises at least one battery.

38. The illumination device as recited in claim 36, wherein the power source comprises a plug configured to be connected to a wall socket.

39. The illumination device as recited in claim 36, wherein the power source comprises an AC power source and further comprising a DC power supply coupled to convert AC current from the power supply into DC power suitable for operating the light emitting diodes.