LIGHT EMITTING DEVICES AND METHODS

• US 20120126257A1
• Filed: 05/10/2011
• Published: 05/24/2012
• Est. Priority Date: 11/22/2010
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Reiherzer, Jesse Colin, Hussell, Christopher P., Andrews, Peter Scott, Emerson, David T.
• Granted Patent: US 8,624,271 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• 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 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/12032 Schottky diode
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Light emitting devices and methods are disclosed. In one embodiment a light emitting device can include a substrate and a plurality of light emitting diodes (LEDs) disposed over the substrate in patterned arrays. The arrays can include one or more patterns of LEDs. A light emitting device can further include a retention material disposed about the array of LEDs. In one aspect, the retention material can be dispensed.

Claims

1. A light emitting device, comprising:

a substrate;

a plurality of light emitting diodes (LEDs) disposed over the substrate in an array, the array comprising a plurality of different patterns of LEDs; and

a retention material dispensed about the array of LEDs.

2. The device of claim 1, wherein the plurality of LEDs are attached to the substrate using flux-assisted eutectic, metal-assisted non-eutectic, or thermal compression die attach.

3. The device of claim 1, wherein the plurality of LEDs is more than 64 LEDs.

4. The device of claim 1, wherein the array of LEDs comprises more than one string of LEDs, the more than one string of LEDs comprising a plurality of LEDs electrically connected in series.

5. The device of claim 1, wherein the LEDs each comprise a length of approximately 470 μ

m or less and a width of approximately 350 μ

m or less.

6. The device of claim 1, wherein the device is operable at approximately 16 volts (V) or less.

7. The device of claim 1, wherein the device is configured for operation at approximately 16 volts (V) or more.

8. The device of claim 1, wherein the device is configured for operation at approximately 42 volts (V) or more.

9. The device of claim 1, wherein the retention material is dispensed over one or more ESD protection devices.

10. The device of claim 4, wherein the substrate comprises first and second electrical traces and each string of LEDs is electrically connected to the first and second electrical traces via electrical connectors.

11. The device of claim 10, wherein the retention material is at least partially dispensed over a portion of the electrical connectors.

12. The device of claim 4, wherein the more than one string of LEDs comprises five or more LEDs electrically connected in series.

13. The device of claim 4, wherein the more than one string of LEDs comprises 14 LEDs electrically connected in series.

14. The device of claim 1, wherein the one or more different patterns comprises at least two of the following arrangements:

(i) a checkerboard arrangement;

(ii) a straight line arrangement; and

(iii) a grid arrangement wherein the LEDs are substantially aligned in at least two directions.

15. A light emitting device, comprising:

a substrate;

one or more strings of light emitting diodes (LEDs) electrically connected in series over the substrate, each string, comprising five or more LEDs; and

the LEDs being attached to the substrate using flux-assisted eutectic, metal-assisted non-eutectic, or thermal compression die attach.

16. The device of claim 15, wherein the one or more strings of LEDs comprise one or more patterns of LEDs.

17. The device of claim 16, wherein the one or more patterns comprises at least two of the following arrangements:

(i) a checkerboard arrangement;

(ii) a straight line arrangement; and

(iii) a grid arrangement wherein the LEDs are substantially aligned in at least two directions.

18. The device of claim 15 comprising more than five strings of LEDs.

19. The device of claim 15 comprising more than 10 strings of LEDs.

20. The device of claim 15 comprising 30 strings of LEDs.

21. The device of claim 16, wherein each string of LEDs comprises 14 LEDs.

22. The device of claim 18, wherein each string of LEDs comprises five LEDs.

23. The device of claim 15, wherein the device comprises more than 64 LEDs.

24. The device of claim 15, wherein the device is configured for operation at approximately 16 volts (V) or more.

25. The device of claim 15, wherein the device is configured for operation at approximately 16 V or less.

26. The device of claim 15, wherein the device is configured for operation at approximately 42 V or more.

27. A method of providing a light emitting device, the method comprising:

providing a substrate;

attaching a plurality of light emitting diodes (LEDs) to the substrate in an array, the array comprising one or more patterns of LEDs; and

dispensing a retention material about the array of LEDs.

28. The method of claim 27, wherein attaching the plurality of LEDs comprises using flux-assisted eutectic, metal-assisted non-eutectic, or thermal compression to die attach the LEDs to the substrate.

29. The method of claim 27, wherein attaching a plurality of LEDs comprises electrically connecting the LEDs in series to first and second conductive traces of the substrate.

30. The method of claim 27, wherein attaching the plurality of LEDs in an array comprises attaching one or more strings of LEDs to the substrate, each string comprising five or more LEDs electrically connected in series.

31. The method of claim 30, wherein attaching one or more strings of LEDs comprises attaching more than five strings of LEDs to the substrate.

32. The method of claim 30, wherein attaching one or more strings of LEDs comprises attaching more than 10 strings of LEDs to the substrate.

33. The method of claim 30, wherein attaching one or more strings of LEDs comprises attaching 30 strings of LEDs to the substrate.

34. The method of claim 27, wherein attaching the plurality of LEDs in an array comprises attaching more than 64 LEDs to the substrate.

35. The method of claim 27, wherein attaching a plurality of LEDs comprises attaching the LEDs in at least two of the following patterns:

(i) a checkerboard arrangement;

(ii) a straight line arrangement; and

(iii) a grid arrangement wherein the LEDs are substantially aligned in at least two directions.

36. A light emitting device, comprising:

a substrate;

a plurality of light emitting diodes (LEDs) disposed over the substrate in an array;

a retention material disposed at least partially around and proximate to the array of LEDs;

the array of LEDs comprising one or more patterns of LEDs, and at least some of the plurality of LEDs being electrically connected by wirebonds to form separate strings of LEDs, wherein each string of LEDs has at least one wirebond that is covered by the retention material.

37. The device of claim 36, wherein the device comprises more than 64 LEDs.

38. The device of claim 36, wherein the LEDs each comprise a length of approximately 470 μ

m or less and a width of approximately 350 μ

m or less.

39. The device of claim 36, the one or more patterns comprise at least two of:

(i) a checkerboard arrangement;

(ii) a straight line arrangement; and

(iii) a grid arrangement wherein the LEDs are substantially aligned in at least two directions.

40. The device of claim 36, wherein the retention material is dispensed over one or more ESD protection devices.

41. The device of claim 36, wherein the plurality of LEDs comprises using flux-assisted eutectic, metal-assisted non-eutectic, or thermal compression to die attach the LEDs to the substrate.