LED LAMP WITH HIGH COLOR RENDERING INDEX

• US 20120161626A1
• Filed: 12/22/2010
• Published: 06/28/2012
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: van de Ven, Antony Paul, Negley, Gerry, Lu, Dong
• Granted Patent: US 9,052,067 B2
• Time in Patent Office: Days
• US Class Current: 315/35
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/235 Details of bases or caps, i.e. the parts that connect the light source to a fitting; Arrangement of components within bases or caps F21K9/238 takes precedence
• CPC Class Codes: F21K 9/237 Details of housings or cases, i.e. the parts between the light-generating element and the bases; Arrangement of components within housings or cases F21K9/238 takes precedence
• CPC Class Codes: F21K 9/238 Arrangement or mounting of circuit elements integrated in the light source
• CPC Class Codes: F21K 9/272 Details of end parts, i.e. the parts that connect the light source to a fitting; Arrangement of components within end parts F21K9/278 takes precedence
• CPC Class Codes: F21K 9/62 using mixing chambers, e.g. housings with reflective walls
• CPC Class Codes: F21K 9/66 Details of globes or covers forming part of the light source
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 23/02 the elements being transformers, impedances or power supply units, e.g. a transformer with a rectifier
• CPC Class Codes: F21V 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/773 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/83 the elements having apertures, ducts or channels, e.g. heat radiation holes
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 3/04 characterised by materials, surface treatments or coatings
• CPC Class Codes: F21V 7/0016 on lighting devices that also provide for direct lighting, e.g. by means of independent light sources, by splitting of the light beam, by switching between both lighting modes
• CPC Class Codes: F21V 7/041 with conical or pyramidal surface
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 : Light-emitting diodes [LED]
• CPC Class Codes: Y10T 29/49002 : Electrical device making
• CPC Class Codes: Y10T 29/49119 : Brush

Abstract

An LED lamp with a high color rendering index (CRI) is disclosed. Example embodiments of the invention provide an LED lamp with a relatively high color rendering index (CRI). In some embodiments, the lamp has other advantageous characteristics, such as good angular uniformity. In some embodiments, the LED lamp is sized and shaped as a replacement for a standard incandescent bulb, and includes an LED assembly with at least first and second LEDs operable to emit light of two different colors. In some embodiments, the lamp can emit light with a color rendering index (CRI) of at least 90 without remote wavelength conversion. In some embodiments, the LED lamp conforms some, most, or all of the product requirements for a 60-watt incandescent replacement for the L prize.

Claims

1. An LED lamp sized and shaped as a replacement for an omnidirectional standard incandescent bulb, the LED lamp comprising:

an LED assembly further comprising at least first and second LEDs operable to emit light of at least two different colors; and

an enclosure configured so that light from the LED assembly, when the LEDs are energized, passes through the enclosure without remote wavelength conversion and is emitted with a color rendering index (CRI) of at least 90.

2. The LED lamp of claim 1 wherein the enclosure comprises a color mixing treatment.

3. The LED lamp of claim 2 wherein the color mixing treatment comprises at least two sections with differing transmittance-to-reflectance ratios.

4. The LED lamp of claim 2 further comprising a conical reflective surface disposed between the LED assembly and a power supply.

5. The LED lamp of claim 2 further comprising a cone reflector disposed above the LED assembly within the enclosure.

6. The LED lamp of claim 4 wherein the enclosure comprises a transparent section opposite the conical reflective surface.

7. The LED lamp of claim 2 further comprising a thermal post disposed between the LED assembly and a power supply.

8. The LED lamp of claim 7 wherein the enclosure comprises a substantially transparent section opposite the thermal post.

9. The LED lamp of claim 8 further comprising an optically optimized surface disposed on the thermal post.

10. The LED lamp of claim 2 further comprising a heat pipe disposed between the LED assembly and a power supply.

11. The LED lamp of claim 10 wherein the enclosure comprises a substantially transparent section opposite the heat pipe.

12. The LED lamp of claim 1 wherein the lamp is operable to emit light with a correlated color temperature (CCT) from 1200K to 3500K.

13. The LED lamp of claim 12 having a luminous efficacy of at least 100 lumens per watt.

14. The LED lamp of claim 12 having a luminous efficacy of at least 90 lumens per watt.

15. The LED lamp of claim 12 having a luminous efficacy of at least 75 lumens per watt.

16. The LED lamp of claim 12 having a luminous efficacy of at least 50 lumens per watt.

17. The LED lamp of claim 14 having a luminous intensity distribution that varies by not more than 10% from 0 to 150 degrees.

18. The LED lamp of claim 14 having a luminous intensity distribution that varies by not more than 20% from 0 to 135 degrees.

19. The LED lamp of claim 18 wherein at least 5% of the total flux is in the 135 to 180 degree zone.

20. The LED lamp of claim 14 having a luminous intensity distribution that varies by not more than 30% from 0 to 120 degrees.

21. The LED lamp of claim 17 having a color spatial uniformity of such that chromaticity with change in viewing angle varies by no more than 0.004 from a weighted average point.

22. The LED lamp of claim 18 having a color spatial uniformity of such that chromaticity with change in viewing angle varies by no more than 0.004 from a weighted average point.

23. The LED lamp of claim 20 having a color spatial uniformity of such that chromaticity with change in viewing angle varies by no more than 0.004 from a weighted average point.

24. The LED lamp of claim 1 wherein the LED lamp conforms to the product requirements for luminous efficacy, color rendering index, color spatial uniformity, light distribution and dimensions and base type of a 60-watt incandescent replacement for the L prize.

25. The LED lamp of claim 24 further comprising a support disposed between the LED assembly and a power supply, wherein the support is selected from a group consisting of a conical reflective surface, a thermal post and a heat pipe.

26. The LED lamp of claim 25 wherein the enclosure comprises a substantially transparent section opposite the support.

27. An LED lamp sized and shaped as a replacement for an omnidirectional standard incandescent bulb, the LED lamp comprising an LED assembly including at least two groups of LEDs, wherein one group, if illuminated, would emit light having a dominant wavelength from 440 to 480 nm, and another group, if illuminated, would emit light having a dominant wavelength from 605 to 630 nm, one group being packaged with a lumiphor, which, when excited, emits light having a dominant wavelength from 560 to 580 nm, wherein the LED lamp is configured so that light from the LED assembly is emitted from the lamp without a remote wavelength conversion.

28. The LED lamp of claim 27 wherein one group of LEDs is arranged in two strings with the other group of LEDs arranged in a single string between the two strings.

29. The LED lamp of claim 28 further comprising a color mixing enclosure configured so that at least some light emitted by the LED assembly exits the LED lamp through the color mixing enclosure.

30. The LED lamp of claim 29 further comprising:

a power supply; and

a support between the LED assembly and the power supply.

31. The LED lamp of claim 30 wherein the support is selected from a group consisting of a conical reflective surface, a thermal post and a heat pipe.

32. The LED lamp of claim 31 wherein the color mixing enclosure includes a transparent section opposite the support.

33. The LED lamp of claim 31 wherein the LED lamp conforms to the product requirements for light distribution, luminous efficacy, color rendering index, color spatial uniformity, dimensions and base type of a 60-watt incandescent replacement for the L prize.

34. A method of making an omnidirectional LED lamp comprising:

providing at least first and second LEDs operable to emit light of two different colors;

packaging the first and second LEDs, including a lumiphor for at least some of the LEDs to produce an LED assembly that emits light that can be combined to provide light with a color rendering index (CRI) of at least 90;

connecting the LED assembly to a power supply; and

installing a color mixing enclosure configured so that at least some light emitted by the LED assembly when the LEDs are energized exits the LED lamp through the color mixing enclosure without remote wavelength conversion.

35. The method of claim 34 further comprising installing the power supply in an enclosure that enables the LED lamp to replace a standard incandescent bulb.

36. The method of claim 35 wherein the LED lamp conforms to the product requirements for light distribution, luminous efficacy, color rendering index, color spatial uniformity, dimensions and base type of a 60-watt incandescent replacement for the L prize.

37. The method of claim 35 wherein the connecting of the LED assembly to the power supply further comprises providing a support disposed between the LED assembly and the power supply, wherein the support is selected from a group consisting of a conical reflective surface, a thermal post and a heat pipe, and wherein the color mixing enclosure includes a transparent section opposite the support.

38. An omnidirectional LED lamp comprising:

an LED assembly with LEDs configured to emit blue-shifted yellow and red/orange light;

an enclosure configured so that light from the LED assembly, when the LEDs are illuminated, passes through the enclosure without remote wavelength conversion and is emitted with a color rendering index (CRI) of at least 90; and

an Edison base.

39. The LED lamp of claim 38 sized and shaped to act as a replacement for a standard A19 bulb.

40. The LED lamp of claim 39 further comprising a conical reflective surface disposed between the LED assembly and a power supply.

41. The LED lamp of claim 39 further comprising a cone reflector disposed above the LED assembly within the enclosure.

42. The LED lamp of claim 40 wherein the enclosure comprises a transparent section opposite the conical reflective surface.

43. The LED lamp of claim 39 further comprising a thermal post disposed between the LED assembly and a power supply.

44. The LED lamp of claim 43 wherein the enclosure comprises a substantially transparent section opposite the thermal post.

45. The LED lamp of claim 44 further comprising an optically optimized surface disposed on the thermal post.

46. The LED lamp of claim 39 further comprising a heat pipe disposed between the LED assembly and a power supply.

47. The LED lamp of claim 46 wherein the enclosure comprises a substantially transparent section opposite the heat pipe.

48. The LED lamp of claim 38 wherein the LED assembly further comprises at least two groups of LEDs, wherein one group, if illuminated, would emit light having a dominant wavelength from 435 to 490 nm, and another group, if illuminated, would emit light having a dominant wavelength from 600 to 640 nm, one group being packaged with a lumiphor, which, when excited, emits light having a dominant wavelength from 540 to 585 nm.

49. The LED lamp of claim 48 wherein the one group, if illuminated, would emit light having a dominant wavelength from 440 to 480 nm, and the other group, if illuminated, would emit light having a dominant wavelength from 605 to 630 nm, one group being packaged with a lumiphor, which, when excited, emits light having a dominant wavelength from 560 to 580 nm.

50. The LED lamp of claim 49 having a luminous intensity distribution that varies by not more than 10% from 0 to 150 degrees.

51. The LED lamp of claim 49 having a luminous intensity distribution that varies by not more than 20% from 0 to 135 degrees.

52. The LED lamp of claim 51 wherein at least 5% of the total flux is in the 135 to 180 degree zone.

53. The LED lamp of claim 49 having a luminous intensity distribution that varies by not more than 30% from 0 to 120 degrees.

54. The LED lamp of claim 52 having a luminous efficacy of at least 100 lumens per watt.

55. The LED lamp of claim 52 having a luminous efficacy of at least 90 lumens per watt.

56. The LED lamp of claim 52 having a luminous efficacy of at least 75 lumens per watt.