Solid state lighting component

• US 20090050907A1
• Filed: 05/23/2008
• Published: 02/26/2009
• Est. Priority Date: 01/10/2005
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald, Ibbetson, James, Keller, Bernd, Tarsa, Eric, Yuan, Thomas
• Granted Patent: US 7,821,023 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• 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
• CPC Class Codes: H01L 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body
• CPC Class Codes: H01L 33/647 the elements conducting electric current to or from the semiconductor body
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/40 Details of LED load circuits

Abstract

An LED component comprising an array of LED chips mounted on a planar surface of a submount with the LED chips capable of emitting light in response to an electrical signal. The LED chips comprise respective groups emitting at different colors of light, with each of the groups interconnected in a series circuit. A lens is included over the LED chips. Other embodiments can comprise thermal spreading structures included integral to the submount and arranged to dissipate heat from the LED chips.

Claims

1. A monolithic white light emitting diode (LED) package, comprising single or multiple color LED chip array generating greater than approximately 800 lumens at less than approximately 3000 K, said LED chip array arranged on a substantially planar substrate with a single overmolded lens.

2. The LED package of claim 1, emitting a white light from the combined emission of LED chips in said LED chip array.

3. The LED package of claim 1, wherein said lens is in direct contact with said LED chip array.

4. The LED package of claim 1, further comprising integrated thermal spreading structures.

5. The LED package of claim 4, wherein said thermal spreading structures comprise thermally conductive traces on said substrate.

6. The LED package of claim 4, wherein said thermal spreading structures comprise die attach pads on said substrate.

7. The LED package of claim 4, wherein said thermal spreading structures comprise an electrically neutral thermally conductive pad.

8. The LED package of claim 9, wherein said electrically neutral pad is on a surface of said substrate opposite said LED chip array.

9. The LED package of claim 4, wherein said thermal spreading structures comprise thermal spreading layers within said substrate.

10. The LED package of claim 9, wherein said thermal spreading structures further comprise partial thermal vias passing through said submount from a surface of said submount opposite said LED chip array.

11. The LED package of claim 1, wherein said LED chip array is arranged in two dimensional substantially symmetrical layout.

12. The LED package of claim 11, wherein said LED chips in said LED chip array have a size of greater than approximately 500 microns.

13. The LED package of claim 12, wherein said LED chips have a size of substantially 700 microns.

14. The LED package of claim 1, wherein said substrate comprises ceramic or metal core board.

15. The LED package of claim 14, wherein said ceramic board has high reflectivity.

16. The LED package of claim 1, wherein said submount comprises a polymetric material.

17. The LED package of claim 1, wherein said substrate has a size of substantially 13 mm by 12 mm.

18. The LED package of claim 1, wherein said substrate is substantially planar and further comprises electrical connections on its front or back surface.

19. The LED package of claim 1, wherein said LED chip array comprises LED chips emitting at two colors wherein the ratio between the number of chips emitting at the two colors is greater than or equal to 4 to 1.

20. The LED package of claim 1, wherein said LED chip array comprises LED chips emitting at two colors wherein the ratio between the number of chips emitting at the two colors is greater than or equal to 3 to 1.

21. The LED package of claim 1, wherein the total number of LED chips in said array is 26.

22. The LED package of claim 1, wherein at least some of said LED chips in said LED chip array are connected in series.

23. A white emitting light emitting diode (LED) package comprising a LED chip array and an overmolded lens over said array having a diameter greater than 5 millimeters.

24. The LED package of claim 23, wherein said lens has a diameter of approximately 11 millimeters.

25. The LED package of claim 23, wherein said LED chip array comprises 26 LED chips, each of which emits light at one of a plurality of colors.

26. The LED package of claim 23, wherein said lens comprises a hemispheric lens having a diameter of approximately 11 millimeters.

27. The LED package of claim 23, wherein said lens has a diameter being approximately the same as or larger than the width of said LED chip array.

28. The LED package of claim 23, wherein the focal point of said lens is located in or below the horizontal plane created by the emitting region of the LED chips.

29. The LED package of claim 23, wherein said lens comprises an aggregate of multiple optical elements.

30. The LED package of claim 23, wherein said lens comprises an essentially flat optically transparent element.

31. A monolithic white light emitting diode (LED) package, comprising single or multiple color LED chip array generating greater than approximately 800 lumens at less than approximately 3000 K, wherein said LED chip array comprises a white emitting LED array having a plurality of phosphor converted yellow-green emitting LED chips and red LED chips.

32. The LED package of claim 31, wherein said LED chips are substantially the same size.

33. The LED package of claim 31, wherein said phosphor converted yellow-green emitting LED chips emit light in a first u′

v′

1976 CIE color space defined by the pentagon of the coordinates A with u′

=0.13;

v′

=0.42, B with u′

=0.13;

v′

=0.57, C with u′

=0.26;

v′

=0.54, D with u′

=0.22;

v′

=0.51, and E with u′

=0.18;

v′

=0.42, and LEDs of said red LED chips emit light in a second color space defined by the quadrangle of the coordinates E with u′

=0.29;

v′

=0.54, F with u′

=0.31;

v′

=0.56, G with u′

=0.55;

v′

=0.55, and H with u′

=0.53;

v′

=0.47.

34. A monolithic light emitting diode (LED) package, comprising a plurality of LED chips, wherein each of said LED chips emits light at one of at least two color groups, wherein the LED chips emitting at each of said color groups are connected in series.

35. The LED package of claim 34, wherein said LED chips are mounted to a substrate and connected in series by circuit traces in a single layer of said substrate.

36. The LED package of claim 35, comprising less than two traces running between said LED chips.

37. The LED package of claim 34, wherein the LEDs of a first of said color groups emit light in a first u′

v′

1976 CIE color space defined by the pentagon of the coordinates A with u′

=0.13;

v′

=0.42, B with u′

=0.13;

v′

=0.57, C with u′

=0.26;

v′

=0.54, D with u′

=0.22;

v′

=0.51, and E with u′

=0.18;

v′

=0.42, and the LEDs of a second of said color groups emit in a second color space defined by the quadrangle of the coordinates E with u′

=0.29;

v′

=0.54, F with u′

=0.31;

v′

=0.56, G with u′

=0.55;

v′

=0.55, and H with u′

=0.53;

v′

=0.47.

38. The LED package of claim 34, wherein at least one of said color groups is divided into a plurality of color LED sub-groups wherein each of said sub-groups emits different colors of light and wherein the combined emission of said sub-groups is approximately equal to the desired emission of said at least one of said color groups.

39. The LED package of claim 34, wherein the LED chips of each of said color groups are arranged on a submount with respect to the LED chips of the other said color groups in a symmetrical geometrical order of substantially circular arrays of approximately the same inscribed area for each color group.

40. The LED package of claim 34, wherein said groups of LEDs are radially offset with respect to each other.

41. The LED package of claim 34, wherein the LED chips of each of said color groups are arranged on a submount further comprising a plurality of bond pads on said submount, wherein an electrical signal is applied to each of said serial connected color groups at a respective two of said bond pads.

42. The LED package of claim 41, wherein said LED chips are mounted on a planar surface of said submount.

43. The LED package of claim 34, further comprising bond pads for applying an electrical signal to said LED chips.

44. The LED package of claim 34, wherein at least some of said LED chips comprise a series/parallel interconnection circuit with interconnection nodes to a parallel circuit of series connected LEDs being placed after groups of one or more series connected LEDs.

45. The LED component of claim 34, wherein the space between adjacent LEDs is in the range of 5 to 500 microns.

46. The LED component of claim 34, wherein said LED chips are arranged on one or more multi-chip LED lamps.