LED LAMPS

• US 20120161193A1
• Filed: 12/20/2011
• Published: 06/28/2012
• Est. Priority Date: 11/19/1997
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Hassan, Salam P. A.
• Granted Patent: US 8,587,020 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: H01L 2224/4824 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A high power LED lamp has a GaN chip placed over an AlGaInP chip. A reflector is placed between the two chips. Each of the chips has trenches diverting light for output. The chip pair can be arranged to produce white light having a spectral distribution in the red to blue region that is close to that of daylight. Also, the chip pair can be used to provide an RGB lamp or a red-amber-green traffic lamp. The active regions of both chips can be less than 50 microns away from a heat sink.

Claims

1. An LED lamp comprising:

a semiconductor structure comprising a lower semiconductor layer having a lower face, an active region, an upper semiconductor layer having an upper face, a left edge, and a right edge;

a first terminal between the left edge and the right edge;

a second terminal distant from the first terminal;

a left track formed on a lower bottom surface lower than the upper face; and

a right track beginning at a position near the right edge and extending toward the left edge.

2. The LED lamp of claim 1, further comprising a left trench, where the left track is formed, having an inclined side wall.

3. The LED lamp of claim 1, further comprising a middle track between the left track and the right track.

4. The LED lamp of claim 1, further comprising a middle track about which the left track and the right track are substantially symmetric.

5. The LED lamp of claim 1, further comprising a conductor formed on the upper semiconductor layer, and between the left track and the right track.

6. The LED lamp of claim 1, further comprising a conductor beginning at the second terminal and extending between the left track and the right track.

7. The LED lamp of claim 1, further comprising a plurality of conductors electrically connected to the second terminal, wherein at least one of the conductors is between the left track and the right track.

8. The LED lamp of claim 1, wherein the left track and the right track are substantially symmetric about the first terminal.

9. An LED lamp comprising:

a semiconductor structure comprising a lower semiconductor layer having a lower face, an active region, an upper semiconductor layer having an upper face through which at least some light from the active region can escape from the semiconductor structure, a first edge, and a second edge opposite to the first edge;

a first conductor and a second conductor, formed on the upper face;

a track formed on a lower bottom surface lower than the upper face, and between the first conductor and the second conductor;

a first terminal electrically connected to the track; and

a second terminal distant from the first terminal and having a width greater than the first conductor.

10. The LED lamp of claim 9, further comprising a trench, where the track is formed, having an inclined side wall.

11. The LED lamp of claim 9, wherein the first conductor and the second conductor are far from the first edge and the second edge respectively.

12. The LED lamp of claim 9, wherein the track is extended toward the second terminal.

13. The LED lamp of claim 9, wherein the first conductor has a segment not parallel to the first edge or the second edge.

14. The LED lamp of claim 9, wherein the first conductor and the second conductor are not symmetric about the second terminal.

15. The LED lamp of claim 9, wherein the first terminal is substantially between the first conductor and the second conductor.

16. An LED lamp comprising:

a semiconductor structure comprising a first semiconductor layer having a lower face, an active region, and a second semiconductor layer having an upper face;

a first terminal electrically connected to the first semiconductor layer and having a first width;

a second terminal electrically connected to the second semiconductor layer and having a second width;

at least two tracks associated with the first terminal, or at least two conductors associated with the second terminal, having at least one width smaller than one of the first width and the second width.

17. The LED lamp of claim 16, further comprising trenches, where the at least two tracks are formed, having at least one inclined side wall.

18. The LED lamp of claim 16, further comprising a cross track connecting the at least two tracks, or a cross conductor connecting the at least two conductors.

19. The LED lamp of claim 16, wherein the at least two tracks and the at least two conductors are interdigitated with each other.

20. The LED lamp of claim 16, wherein the at least two tracks or the at least two conductors have varied widths.