LED light engine for AC operation and methods of fabricating same

• US 20040075399A1
• Filed: 10/22/2002
• Published: 04/22/2004
• Est. Priority Date: 10/22/2002
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hall, David Charles
• Granted Patent: US 7,009,199 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate

Abstract

A light engine comprises a pair of LED active elements mounted on a common header having first and second terminals. The first terminal is connected to the cathode of the first LED active element and the anode of the second LED active element, while the second terminal is connected to the anode of the first LED active element and the cathode of the second LED active element, thereby connecting the LEDs in an anti-parallel arrangement. A light engine having a single insulating or semi-insulating substrate having formed thereon plural LED active elements with associated p- and n-type contacts forming cathode and anode contacts, respectively, for each LED active element is also provided. The LED active elements may be mounted in a flip-chip configuration on a header having a plurality of leads. The header may include a pair of leads adapted such that two LEDs may be flip-mounted thereon with the anode of the first LED and the cathode of the second LED contacting one lead, while the cathode of the first LED and the anode of the second LED contact the other lead. In addition, the header may be adapted to permit a substrate having multiple active elements to be mounted thereon.

Claims

1. An electronic device comprising:

a header;

first and second LEDs comprising a substrate, an epitaxial region, and anode and cathode electrical contacts, respectively, the first and second LEDs mounted on the header in a flip-chip configuration; and

wherein the header is configured to electrically connect the first and second LEDs in an anti-parallel arrangement.

2. An electronic device as recited in claim 1, further comprising:

first and second conductive leads formed on the header; and

wherein the anode of first LED and the cathode of the second LED are in electrical contact with the first conductive lead and the cathode of the first LED and the anode of the second LED are in electrical contact with the second conductive lead.

3. An electronic device as recited in claim 2, wherein the first and second LEDs are thermosonically bonded to the conductive leads.

4. An electronic device as recited in claim 2, wherein said the first and second LEDs are soldered to the conductive leads.

5. An electronic device as recited in claim 2, wherein the substrate of the first LED and the substrate of the second LED comprise 6H-SiC.

6. An electronic device as recited in claim 2, wherein the substrate of said first LED and the substrate of the second LED comprise one of insulating material or semi-insulating material.

7. An electronic device as recited in claim 2, further comprising at least one circuit element disposed on the header and electrically connected to at least one of the first conductive lead and/or the second conductive lead.

8. An electronic device as recited in claim 2, wherein the substrate of the first LED and/or the substrate of the second LED is shaped to enhance light extraction.

9. An electronic device as recited in claim 2, wherein the substrate of the first LED and/or the substrate of the second LED is coated with a wavelength conversion material.

10. An electronic device as recited in claim 9, wherein the wavelength conversion material comprises a phosphor.

11. An electronic device, comprising:

a header having first and second conductive leads formed thereon;

an LED comprising a substrate and first and second active elements on the substrate, wherein each of the first and second active elements comprises an epitaxial region, and anode and cathode electrical contacts, respectively, the LED being mounted on the header in a flip-chip configuration so as to contact the first and second conductive leads so as to electrically connect the first and second active elements in an anti-parallel arrangement.

12. An electronic device as recited in claim 11, wherein the LED is thermosonically bonded to the conductive leads.

13. An electronic device as recited in claim 11, wherein the LED is soldered to said conductive leads.

14. An electronic device as recited in claim 11, wherein the substrate comprises 6H—

SiC.

15. An electronic device as recited in claim 11, wherein the substrate comprises one of insulating or semi-insulating material.

16. An electronic device as recited in claim 11, further comprising at least one circuit element disposed on the header and electrically connected to at least one of the first conductive lead and/or the second conductive lead.

17. An electronic device as recited in claim 11, wherein the substrate is shaped to enhance light extraction.

18. An electronic device as recited in claim 11, wherein the substrate is coated with a wavelength conversion material.

19. An electronic device as recited in claim 18, wherein the wavelength conversion material comprises a phosphor.

20. A method of manufacturing a light emitting device, comprising:

providing a semiinsulating or insulating substrate;

forming an epitaxial region on the substrate, the epitaxial region comprising at least an n-type contact layer on the substrate, an active region on the n-type contact layer, and a p-type contact layer on the active region;

selectively etching the epitaxial region to reveal a plurality of contact areas of the n-type contact layer;

isolating a plurality of active elements within the epitaxial region, each of the active elements including at least one revealed contact area of the n-type contact layer; and

forming anode and cathode ohmic contacts on each of the active elements.

21. The method of claim 20, wherein isolating a plurality of active elements comprises etching a plurality of mesas in the epitaxial region to define isolated active elements.

22. The method of claim 20, further comprising:

mounting the device on a header in a flip-chip configuration, the header comprising a plurality of conductive leads, wherein each of the anode and cathode contacts of each of the active elements is in electrical contact with at least one of each of the plurality of conductive leads.

23. The method of claim 20, further comprising shaping the substrate to improve light extraction.

24. The method of claim 20, further comprising coating the substrate with a wavelength-converting material.

25. The method of claim 20, further comprising encapsulating the device with an encapsulant including a wavelength-converting material.

26. The method of claim 25, wherein the wavelength converting material comprises a phosphor.

27. The method of claim 24, wherein the wavelength converting material comprises a phosphor.

29. The electronic device of claim 27, wherein the plurality of LED active elements comprise an LED mounted on the header in a flip-chip configuration, the LED comprising a substrate and a plurality of active elements on the substrate, wherein each of the plurality of active elements comprises an epitaxial region, and anode and cathode electrical contacts, respectively.

30. The electronic device of claim 27, wherein the plurality of LED active elements comprise a plurality of discrete LEDs, each of the plurality of discrete LEDs being mounted in a flip-chip configuration on the header.

32. The electronic device of claim 30, wherein the header is further configured to parallel electrically connect the serially electrically connected pairs of the plurality of active elements that are connected in an anti-parallel manner.

28. An electronic device, comprising:

a header;

a plurality of LED active elements mounted on the header in a flip-chip configuration; and

wherein the header is configured to electrically connect respective pairs of the plurality of active elements in anti-parallel manner.

31. The electronic device of claim 28, wherein the header is further configured to serially electrically connect pairs of the plurality of active elements that are connected in an anti-parallel manner.

33. The electronic device of claim 28, wherein the header comprises conductive leads disposed to contact adjacent ones of the plurality of active elements such that at least two conductive leads are disposed between each of the plurality of active elements and a substrate of the header.