LED lamp with high color rendering index

• US 9,052,067 B2
• Filed: 12/22/2010
• Issued: 06/09/2015
• 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
• Primary Examiner(s): Guharay, Karabi
• Application Number:
  US12/975,820
• Publication Number:
  US 20120161626A1
• Time in Patent Office: 1,630 Days
• Field of Search: 362230-231, 362/84, 362/294, 313/46
• US Class Current: 1/1
• 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 in LED device packages operable to emit light of at least two different colors;

a support between the LED assembly and a power supply; and

a domed enclosure comprising a color mixing section and a substantially transparent section closer to the power supply, the substantially transparent section having a higher transmittance-to-reflectance ratio than most of the domed enclosure;

wherein the domed enclosure is also configured so that light from the LED assembly, when the LEDs are energized, passes through the domed enclosure without wavelength conversion outside of the LED device packages and is emitted in a substantially omnidirectional pattern with a color rendering index (CRI) of at least 90.

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

3. The LED lamp of claim 2 wherein the support further comprises a conical reflective surface.

4. The LED lamp of claim 2 further comprising a cone reflector disposed above the LED assembly within the domed enclosure positioned to direct light downward through the section of the domed enclosure having the higher transmittance-to-reflectance ratio.

5. The LED lamp of claim 2 wherein the support further comprises a thermal post.

6. The LED lamp of claim 5 further comprising an optically optimized surface disposed on the thermal post.

7. The LED lamp of claim 2 wherein the support further comprises a heat pipe.

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

9. The LED lamp of claim 8 having a luminous efficacy of at least 100 lumens per watt.

10. The LED lamp of claim 8 having a luminous efficacy of at least 90 lumens per watt.

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

12. The LED lamp of claim 11 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.

13. The LED lamp of claim 10 having a luminous intensity distribution that varies by not more than 20% from 0 to 135 degrees.

14. The LED lamp of claim 13 wherein at least 5% of the total flux is in the 135 to 180 degree zone.

15. The LED lamp of claim 13 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.

16. The LED lamp of claim 10 having a luminous intensity distribution that varies by not more than 30% from 0 to 120 degrees.

17. The LED lamp of claim 16 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.

18. The LED lamp of claim 8 having a luminous efficacy of at least 75 lumens per watt.

19. The LED lamp of claim 8 having a luminous efficacy of at least 50 lumens per watt.

20. 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.

21. 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 a second group, if illuminated, would emit light having a dominant wavelength from 605 to 630 nm, the 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 includes a support 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 so that light from the LED assembly is emitted in a substantially omnidirectional pattern without wavelength conversion and with a color rendering index (CRI) of at least 90 through a domed enclosure having a substantially transparent section close to the LED assembly.

22. The LED lamp of claim 21 wherein the one group of LEDs is arranged in two strings with the second group of LEDs arranged in a single string between the two strings.

23. The LED lamp of claim 21 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.

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

providing at least first and second LEDs in LED device packages 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;

providing a support between the LED assembly and a power supply;

connecting the LED assembly to the power supply; and

installing a domed enclosure further comprising a color mixing section, and a substantially transparent section closer to the power supply, the substantially transparent section having a higher transmittance-to-reflectance ratio than most of the domed enclosure so that at least some light emitted by the LED assembly when the LEDs are energized exits the LED lamp through the domed enclosure in a substantially omnidirectional pattern without wavelength conversion outside of the LED device packages.

25. The method of claim 24 further comprising installing the power supply to enable the LED lamp to replace a standard incandescent bulb.

26. The method of claim 25 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.

27. The method of claim 25 wherein the support is selected from a group consisting of a conical reflective surface, a thermal post and a heat pipe.

28. An omnidirectional LED lamp comprising:

an LED assembly with LEDs configured as two groups of LEDs, wherein one group, if illuminated, would emit light having a dominant wavelength from 435 to 490 nm and is packaged with a lumiphor, which, when excited, emits light having a dominant wavelength from 540 to 585 nm, and a second group, if illuminated, would emit light having a dominant wavelength from 600 to 640 nm;

a domed enclosure configured to include a section closer to the LED assembly having a higher transmittance-to-reflectance ratio than most of the domed enclosure so that light from the LED assembly, when the LEDs are illuminated, passes through the domed enclosure without remote wavelength conversion and is emitted in a substantially omnidirectional pattern with a color rendering index (CRI) of at least 90; and

an Edison base.

29. The LED lamp of claim 28 sized and shaped to act as a replacement for a standard A19 bulb.

30. The LED lamp of claim 29 further comprising a conical reflective surface disposed between the LED assembly and a power supply.

31. The LED lamp of claim 29 further comprising a cone reflector disposed above the LED assembly within the domed enclosure positioned to direct light downward through the section of the domed enclosure having the higher transmittance-to-reflectance ratio.

32. The LED lamp of claim 29 further comprising a thermal post disposed between the LED assembly and a power supply.

33. The LED lamp of claim 32 further comprising an optically optimized surface disposed on the thermal post.

34. The LED lamp of claim 29 further comprising a heat pipe disposed between the LED assembly and a power supply.

35. The LED lamp of claim 28 wherein the one group, if illuminated, would emit light having a dominant wavelength from 440 to 480 nm, and the second 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.

36. The LED lamp of claim 35 having a luminous intensity distribution that varies by not more than 10% from 0 to 150 degrees.

37. The LED lamp of claim 35 having a luminous intensity distribution that varies by not more than 20% from 0 to 135 degrees.

38. The LED lamp of claim 37 wherein at least 5% of the total flux is in the 135 to 180 degree zone.

39. The LED lamp of claim 38 having a luminous efficacy of at least 100 lumens per watt.

40. The LED lamp of claim 38 having a luminous efficacy of at least 90 lumens per watt.

41. The LED lamp of claim 38 having a luminous efficacy of at least 75 lumens per watt.

42. The LED lamp of claim 35 having a luminous intensity distribution that varies by not more than 30% from 0 to 120 degrees.