Light emitting devices for light emitting diodes (LEDs)

• US 9,209,354 B2
• Filed: 01/06/2014
• Issued: 12/08/2015
• Est. Priority Date: 11/22/2010
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hussell, Christopher P., Andrews, Peter Scott, Reiherzer, Jesse Colin, Emerson, David T.
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US14/148,102
• Publication Number:
  US 20140183577A1
• Time in Patent Office: 701 Days
• Field of Search: 257 12- 13, 257/81, 257/84, 257 87- 88, 257 98- 99, 438/22, 438 25- 28, 438 48- 52, 438/E31.117, 438/E21.592, 313501-506
• US Class Current: 1/1
• 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 for light emitting diodes (LEDs) 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 diode (LED) device, comprising:

a substrate;

a plurality of LED chips disposed in an array over the substrate for emitting light from a light emission area, wherein the LED chips are spaced apart to extend at least substantially a full length of the light emission area and at least substantially a full width of the light emission area to minimize light absorbed or blocked by neighboring LED chips, and wherein at least some of LED chips in the array are serially connected in a checkerboard pattern with LED chips alternating both above and below a horizontal line; and

a retention material at least partially disposed about the plurality of LED chips.

2. The device of claim 1, wherein each LED chip comprises a length of approximately 470 μ

m or less and a width of approximately 350 μ

m or less.

3. The device of claim 2, wherein the array of LED chips comprises:

at least a first string of LED chips; and

at least a second string of LED chips, wherein an intra-string spacing between one LED chip in the first string and a closest LED chip in the second string is more than twice the width of the LED chips.

4. The device of claim 3, wherein the intra-string spacing is approximately 750 μ

m or more.

5. The device of claim 1, wherein the array comprises multiple strings of serially connected LED chips, and wherein an intra-string spacing between one LED chip in the first string and a closest LED chip in the second string is approximately 750 μ

m or more.

6. The device of claim 1, wherein the array of LED chips comprises at least a first string of serially connected LED chips, and wherein an inter-string spacing between adjacent at least two LED chips in the first string is approximately 125 μ

m or more.

7. The device of claim 6, wherein the inter-string spacing is approximately 210 μ

m or more.

8. The device of claim 6, wherein the inter-string spacing is approximately 225 μ

m or more.

9. The device of claim 1, wherein the array of LED chips comprises at least four strings of serially connected LED chips.

10. The device of claim 1, wherein the array of LED chips comprises at least six strings of serially connected LED chips.

11. The device of claim 1, wherein the array of LED chips comprises at least eight strings of serially connected LED chips.

12. The device of claim 1, wherein the array comprises multiple strings of serially connected LED chips arranged in more than one pattern.

13. The device of claim 12, wherein at least one pattern is linear.

14. The device of claim 12, wherein at least one pattern is non-linear.

15. The device of claim 1, wherein the LED chips are directly attached to a mounting pad.

16. The device of claim 15, wherein the LED chips are directly attached to the mounting pad via flux-assisted eutectic, metal-assisted non-eutectic, or thermal compression die attach technique.

17. The device of claim 1, wherein each of the plurality of LED chips are adapted to emit a same color of light.

18. The device of claim 1, wherein the plurality of LED chips are adapted to emit at least two different colors of light.

19. A method of providing a light emitting diode (LED) device, the method comprising:

providing a substrate;

serially connecting a plurality of LED chips in an array over the substrate for emitting light from a light emission area, wherein the LED chips extend at least substantially a full length of the light emission area and at least substantially a full width of the light emission area whereby light absorbed or blocked by neighboring LED chips is minimized, and wherein at least some of serially connected LED chips in the array are disposed in a checkerboard pattern with LED chips alternating both above and below a horizontal line; and

dispensing a retention material at least partially about the light emission area.

20. The method of claim 19, wherein each LED chip comprises a length of approximately 470 μ

m or less and a width of approximately 350 μ

m or less.

21. The method of claim 20, wherein serially connecting a plurality of LED chips comprises:

serially connecting LED chips in a first string of LED chips;

serially connecting LED chips in a second string; and

wherein an intra-string spacing between one LED chip in the first string and a closest LED chip in the second string is more than twice the width of the LED chips.

22. The method of claim 21, wherein the intra-string spacing is approximately 750 μ

m or more.

23. The method of claim 19, wherein the array comprises multiple strings of serially connected LED chips, and wherein an intra-string spacing between the one LED chip in the first string and the closest LED chip in the second string is approximately 750 μ

m or more.

24. The method of claim 19, wherein serially connecting a plurality of LED chips in an array comprises serially connecting LED chips in a first string across the length of the mounting pad, and wherein an inter-string spacing between at least two adjacent LED chips within the first string is approximately 125 μ

m or more.

25. The method of claim 24, wherein the inter-string spacing is approximately 210 μ

m or more.

26. The method of claim 24, wherein the inter-string spacing is approximately 225 μ

m or more.

27. The method of claim 19, wherein serially connecting a plurality of LED chips comprises serially connecting at least four strings of LED chips.

28. The method of claim 19, wherein serially connecting a plurality of LED chips comprises serially connecting at least six strings of LED chips.

29. The method of claim 19, wherein serially connecting a plurality of LED chips comprises serially connecting at least eight strings of LED chips.

30. The method of claim 19, wherein serially connecting a plurality of LED chips comprises arranging the LED chips in more than one pattern.

31. The method of claim 30, wherein at least one pattern is linear.

32. The method of claim 30, wherein at least one pattern is non-linear.

33. The method of claim 19, further comprising directly attaching the LED chips to a mounting pad.

34. The method of claim 31, wherein directly attaching the LED chips comprises attaching the LED chips via a flux-assisted eutectic, a metal-assisted non-eutectic, or thermal compression die attach technique.