MULTI-CHIP LIGHT EMITTING DEVICE LAMPS FOR PROVIDING HIGH-CRI WARM WHITE LIGHT AND LIGHT FIXTURES INCLUDING THE SAME

• US 20070223219A1
• Filed: 05/02/2007
• Published: 09/27/2007
• Est. Priority Date: 01/10/2005
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Keller, Bernd, McClear, Mark, Medendorp, Nicholas, LeToquin, Ronan, Brandes, Georges
• Granted Patent: US 8,125,137 B2
• Time in Patent Office: Days
• US Class Current: 362/231
• CPC Class Codes: C09K 11/586 with alkaline earth metals
• CPC Class Codes: C09K 11/623 with zinc or cadmium
• CPC Class Codes: C09K 11/7421 with alkaline earth metals
• CPC Class Codes: C09K 11/7702 with zinc or cadmium
• 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: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 23/005 the substrate is supporting also the light source
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• CPC Class Codes: F21Y 2113/17 forming a single encapsulated light source
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A multi-chip lighting emitting device (LED) lamp for providing white light includes a submount including first and second die mounting regions thereon. A first LED chip is mounted on the first die mounting region, and a second LED chip is mounted on the second die mounting region. The LED lamp is configured to emit light having a spectral distribution including at least four different color peaks to provide the white light. For example, a first conversion material may at least partially cover the first LED chip, and may be configured to absorb at least some of the light of the first color and re-emit light of a third color. In addition, a second conversion material may at least partially cover the first and/or second LED chips, and may be configured to absorb at least some of the light of the first and/or second colors and re-emit light of a fourth color. Related light fixtures and methods are also discussed.

Claims

1. A multi-chip light emitting device (LED) lamp for providing white light, comprising:

a submount including first and second die mounting regions thereon;

a first LED chip mounted on the first die mounting region; and

a second LED chip mounted on the second die mounting region,

wherein the LED lamp is configured to emit light having a spectral distribution including at least four different color peaks to provide the white light.

2. The lamp of claim 1, wherein the first LED chip is configured to emit light of a first color, wherein the second LED chip is configured to emit light of a second color, and further comprising:

a first conversion material at least partially covering the first LED chip and configured to absorb at least some of the light of the first color and re-emit light of a third color; and

a second conversion material at least partially covering the first and/or second LED chips and configured to absorb at least some of the light of the first and/or second colors and re-emit light of a fourth color.

3. The lamp of claim 2, wherein coverage of the first and second conversion materials does not overlap.

4. The lamp of claim 2, wherein the first and second conversion materials are configured to re-emit light having a greater wavelength than that of the light emitted by the first and/or second LED chips.

5. The lamp of claim 4, wherein the first LED chip is configured to emit light within a blue wavelength range, wherein the second LED chip is configured to emit light within a cyan wavelength range, wherein the first conversion material comprises a yellow-emitting phosphor, and wherein the second conversion material comprises a red-emitting phosphor.

6. The lamp of claim 2, wherein the first conversion material comprises a first semiconductor layer on the first LED chip, and wherein the second conversion material comprises a second semiconductor layer on the second LED chip.

7. The lamp of claim 6, wherein the first and second semiconductor layers comprise direct bandgap semiconductors having respective bandgaps that are narrower than those of quantum wells of the first and second LED chips.

8. The lamp of claim 7, wherein the first and/or second semiconductor layers comprise a quantum well structure.

9. The lamp of claim 1, wherein the submount further includes a third die mounting region thereon, wherein the first LED chip is configured to emit light of a first color, wherein the second LED chip is configured to emit light of a second color, and further comprising:

a third LED chip mounted on the third die mounting region and configured to emit light of a third color; and

a conversion material at least partially covering the first LED chip and configured to absorb at least some of the light of the first color and re-emit light of a fourth color.

10. The lamp of claim 9, wherein the third LED chip is configured to emit light having a wavelength greater than that of the second LED chip, wherein the second LED chip is configured to emit light having a wavelength greater than that of the first LED chip, and wherein the conversion material is configured to re-emit light having a wavelength between that of the second LED chip and that of the third LED chip.

11. The lamp of claim 10, wherein the first LED chip is configured to emit light within a blue wavelength range, wherein the second LED chip is configured to emit light within a cyan wavelength range, and wherein the third LED chip is configured to emit light within a red wavelength range.

12. The lamp of claim 11, wherein the conversion material comprises a yellow-emitting phosphor.

13. The lamp of claim 12, wherein a combination of the light emitted from the first, second, and third LED chips and the conversion material has a color temperature of about 2600 K to about 6000 K and/or a color-rendering index (CRI) of about 95 or more.

14. The lamp of claim 9, wherein the conversion material covers the first and second LED chips, and wherein the first and second LED chips are configured to emit light of a same color.

15. The lamp of claim 14, wherein the first and second LED chips are configured to emit light within a blue wavelength range, and wherein the third LED chip is configured to emit light within a red wavelength range.

16. The lamp of claim 9, wherein the conversion material covers the first, second, and third LED chips.

17. The lamp of claim 16, wherein the conversion material comprises a yellow-emitting phosphor and/or a red-emitting phosphor.

18. The lamp of claim 9, wherein the conversion material comprises a first phosphor coating, and further comprising:

a second phosphor coating covering the first, second, and third LED chips,

wherein the first and second phosphor coatings are configured to emit light of different colors.

19. The lamp of claim 18, wherein the first phosphor coating comprises a yellow-emitting phosphor, wherein the first LED chip is configured to emit light within a blue wavelength range, and wherein the second phosphor comprises a red-emitting phosphor.

20. The lamp of claim 1, wherein the submount further includes third and fourth die mounting regions thereon, and further comprising:

a third LED chip mounted on the third die mounting region and configured to emit light of a third color; and

a fourth LED chip mounted on the fourth die mounting region.

21. The lamp of claim 20, further comprising:

a conversion material at least partially covering the first LED chip and configured to absorb at least some of the light of the first color and re-emit light of a fourth color.

22. The lamp of claim 21, wherein the conversion material at least partially covers the fourth LED chip, and wherein the fourth LED chip is configured to emit light of the first color.

23. The lamp of claim 22, wherein the first and fourth die mounting regions are diametrically opposed on the submount.

24. The lamp of claim 20, wherein the first LED chip is configured to emit light within a blue wavelength range, wherein the second LED chip is configured to emit light within a cyan wavelength range, wherein the third LED chip is configured to emit light within a red wavelength range, and wherein the fourth LED chip is configured to emit light within a green and/or amber wavelength range.

25. The lamp of claim 21, wherein the conversion material comprises a first phosphor coating, and further comprising:

a second phosphor coating at least partially covering the second LED chip;

a third phosphor coating at least partially covering the third LED chip; and

a fourth phosphor coating at least partially covering the fourth LED chip.

26. The lamp of claim 25, further comprising:

a fifth phosphor coating at least partially covering the first, second, third, and fourth LED chips.

27. The lamp of claim 1, wherein the first and/or second LED chips are individually addressable.

28. The lamp of claim 1, wherein the first and/or second LED chips comprise a light-emitting diode (LED), an organic light-emitting diode (OLED), and/or a laser light source.

29. A light emitting device (LED) light fixture for providing white light, comprising:

a mounting plate; and

a plurality of multi-chip LED lamps attached to the mounting plate, wherein each of the plurality of multi-chip LED lamps comprises;

a submount including first and second die mounting regions thereon;

a first LED chip mounted on the first die mounting region; and

a second LED chip mounted on the second die mounting region,

wherein at least one of the plurality of multi-chip LED lamps is configured to emit light having a spectral distribution including at least four different color peaks to provide the white light.

30. The light fixture of claim 29, wherein the first LED chip is configured to emit light of a first color, wherein the second LED chip is configured to emit light of a second color, and wherein the at least one of the plurality of multi-chip LED lamps further comprises:

a first conversion material at least partially covering the first LED chip and configured to absorb at least some of the light of the first color and re-emit light of a third color; and

a second conversion material at least partially covering the first and/or second LED chips and configured to absorb at least some of the light of the first and/or second colors and re-emit light of a fourth color.

31. The light fixture of claim 30, wherein coverage of the first and second conversion materials does not overlap.

32. The light fixture of claim 30, wherein the first and second conversion materials are configured to re-emit light having a greater wavelength than that of the light emitted by the first and/or second LED chips.

33. The light fixture of claim 32, wherein the first LED chip is configured to emit light within a blue wavelength range, wherein the second LED chip is configured to emit light within a cyan wavelength range, wherein the first conversion material comprises a yellow-emitting phosphor, and wherein the second conversion material comprises a red-emitting phosphor.

34. The light fixture of claim 30, wherein the first conversion material comprises a first semiconductor layer on the first LED chip, and wherein the second conversion material comprises a second semiconductor layer on the second LED chip.

35. The light fixture of claim 34, wherein the first and second semiconductor layers comprise direct bandgap semiconductors having respective bandgaps that are narrower than those of quantum wells of the first and second LED chips.

36. The light fixture of claim 35, wherein the first and/or second semiconductor layers comprise a quantum well structure.

37. The light fixture of claim 29, wherein the first LED chip is configured to emit light of a first color, wherein the second LED chip is configured to emit light of a second color, and wherein the at least one of the plurality of multi-chip LED lamps further comprises:

a third LED chip configured to emit light of a third color mounted on a third die mounting region of the submount; and

a conversion material at least partially covering the first LED chip and configured to absorb at least some of the light of the first color and re-emit light of a fourth color.

38. The light fixture of claim 37, wherein the third LED chip is configured to emit light having a wavelength longer than that of the second LED chip, wherein the second LED chip is configured to emit light having a wavelength longer than that of the first LED chip, and wherein the conversion material is configured to emit light having a wavelength between that of the second LED chip and that of the third LED chip.

39. The light fixture of claim 38, wherein the first LED chip is configured to emit light within a blue wavelength range, wherein the second LED chip is configured to emit light within a cyan wavelength range, and wherein the third LED chip is configured to emit light within a red wavelength range.

40. The light fixture of claim 39, wherein the first LED chip is configured to emit light at a peak wavelength of about 440 nm to about 470 nm, wherein the second LED chip is configured to emit light at a peak wavelength of about 495 nm to about 515 nm, and wherein the third LED chip is configured to emit light at a peak wavelength of about 610 nm to about 630 nm.

41. The light fixture of claim 39, wherein the conversion material comprises a yellow-emitting phosphor.

42. The light fixture of claim 29, wherein the at least one of the plurality of multi-element LED lamps further comprises:

a third LED chip configured to emit light of a third color mounted on a third die mounting region of the submount; and

a fourth LED chip mounted on a fourth die mounting region of the submount.

43. The light fixture of claim 42, wherein the at least one of the plurality of multi-element LED lamps further comprises:

a conversion material at least partially covering the first LED chip and configured to absorb at least some of the light of the first color and re-emit light of a fourth color.

44. The light fixture of claim 43, wherein the conversion material at least partially covers the fourth LED chip, and wherein the fourth LED chip is configured to emit light of the first color.

45. The light fixture of claim 37, wherein the first, second, and third LED chips are individually addressable, and further comprising:

a control circuit electrically coupled to ones of the plurality of multi-chip LED lamps and configured to respectively apply first, second, and third drive currents to the first, second, and third LED chips in the at least one of the plurality of multi-chip LED lamps.

46. The light fixture of claim 45, wherein the control circuit is configured to independently apply the first, second, and third drive currents to the first, second, and third LED chips at a ratio such that a combination of the light emitted from the first, second, and third LED chips and the phosphor coating has a color temperature of about 2600 K to about 6000 K and/or a color-rendering index (CRI) of about 95 or more.

47. The light fixture of claim 29, further comprising:

at least one single-chip LED lamp attached to the mounting plate adjacent the plurality of multi-chip LED lamps.

48. The light fixture of claim 29, wherein the plurality of multi-chip LED lamps are configured to emit light such that a combination of the light has a brightness output and/or CRI that is greater than or equal to that of a similarly-sized incandescent and/or fluorescent light source.

49. The light fixture of claim 29, wherein the first and/or second LED chips comprise a light-emitting diode (LED), an organic light-emitting diode (OLED), and/or a laser light source.

50. A multi-chip light emitting device (LED) lamp for providing white light, comprising:

a submount including first, and second die mounting regions thereon;

a blue LED chip mounted on the first die mounting region and configured to emit light within a blue wavelength range responsive to a first bias current; and

a cyan LED chip mounted on the second die mounting region and configured to emit light within a cyan wavelength range responsive to a second bias current; and

a phosphor material at least partially covering the blue LED chip and configured to convert at least some of the light within the blue wavelength range to light within a yellow wavelength range.

51. The lamp of claim 50, further comprising:

a second phosphor material at least partially covering the cyan LED chip and configured to convert at least some of the light within the cyan wavelength range to light within a red wavelength range.

52. The lamp of claim 50, wherein the phosphor material comprises a semiconductor layer on the blue LED chip that has a bandgap narrower than that of quantum wells of the blue LED chip.

53. The lamp of claim 50, wherein the submount further comprises a third die mounting region, and further comprising:

a red LED chip mounted on the third die mounting region and configured to emit light within a red wavelength range responsive to a third bias current.

54. The lamp of claim 53, wherein the submount further comprises a fourth die mounting region, and further comprising:

a second blue LED chip mounted on the fourth die mounting region and configured to emit light within the blue wavelength range,

wherein the phosphor material at least partially covers the second blue LED chip.

55. The lamp of claim 54, wherein the first and fourth die mounting regions are diametrically opposed on the submount.

56. The lamp of claim 54, wherein the phosphor-containing region at least partially covers the red and cyan LED chips and is further configured to emit light within the red wavelength range.

57. The lamp of claim 54, further comprising:

a second phosphor material at least partially covering the first and second blue LED chips, the red LED chip, and the cyan LED chip,

wherein the second phosphor material is configured to emit light within a red wavelength range.

58. The lamp of claim 55, wherein the blue LED chip is configured to emit light at a peak wavelength of about 440 nm to about 470 nm, wherein the cyan LED chip is configured to emit light at a peak wavelength of about 495 nm to about 515 nm, and wherein the red LED chip is configured to emit light at a peak wavelength of about 610 nm to about 630 nm.

59. A solid state lighting fixture including a plurality of multi-chip LED lamps as recited in claim 50.

60. A method of operating a multi-element light emitting device (LED) lamp comprising blue, cyan, and red LED chips, the method comprising:

independently applying first, second, and third drive currents to the blue, cyan, and red LED chips at a ratio such that a combination of the light emitted from the blue, cyan, and red LED chips provides white light having a color temperature of about 2600 K to about 6000 K and/or a color-rendering index (CRI) of about 95.

61. A light emitting device (LED) lamp for providing white light, comprising:

a submount including a die mounting region thereon;

an LED chip mounted on the die mounting region and configured to emit light of a first color; and

a semiconductor layer on the LED chip and configured to absorb at least some of the light of the first color and re-emit light of another color.

62. The lamp of claim 61, wherein the semiconductor layer comprises a direct bandgap semiconductor material having a narrower bandgap than that of quantum wells of the LED chip.

63. The lamp of claim 61, wherein the semiconductor layer comprises a quantum well structure.

64. The lamp of claim 61, wherein the submount further includes a second die mounting region thereon, wherein the semiconductor layer is configured to re-emit light of a third color, and further comprising:

a second LED chip mounted on the second die mounting region and configured to emit light of a second color; and

a second semiconductor layer on the second LED chip and configured to absorb at least some of the light of the second color and re-emit light of a fourth color.

65. The lamp of claim 64, wherein at least one of the first and/or second semiconductor layer comprises a thin film layer extending on both the first and second LED chips.