High efficacy semiconductor light emitting devices employing remote phosphor configurations

• US 8,853,712 B2
• Filed: 10/26/2012
• Issued: 10/07/2014
• Est. Priority Date: 11/18/2008
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hussell, Christopher P., Tudorica, Florin, Emerson, David Todd, Bergmann, Michael John, Pun, Arthur Fong-Yuen
• Primary Examiner(s): MENZ, DOUGLAS M
• Application Number:
  US13/661,909
• Publication Number:
  US 20130069089A1
• Time in Patent Office: 711 Days
• Field of Search: 257/80, 257/88
• US Class Current: 257/80
• 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 9/61 using light guides
• 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 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 3/049 Patterns or structured surfaces for diffusing light, e.g. frosted surfaces
• CPC Class Codes: F21V 3/061 the material being glass
• CPC Class Codes: F21V 3/062 the material being plastics
• CPC Class Codes: F21V 3/10 characterised by coatings
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 5/0236 the diffusion taking place within the volume of the element
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 6/0003 the light guides being doped with fluorescent agents
• CPC Class Codes: G02B 6/001 the light being emitted along at least a portion of the lateral surface of the fibre
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type

Abstract

A semiconductor light emitting apparatus a semiconductor light emitting device configured to emit light inside a hollow shell including wavelength conversion material dispersed therein or thereon. A semiconductor light emitting apparatus according to some embodiments is capable of generating in excess of 250 lumens per watt, and in some cases up to 270 lumens per watt.

Claims

1. A semiconductor light emitting apparatus comprising:

a wavelength conversion element comprising wavelength conversion material; and

a plurality of light emitting diodes that are oriented to emit light to impinge upon the wavelength conversion element;

wherein the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 2000 K and 8000 K.

2. An apparatus according to claim 1 wherein the light emitting diodes are connected in parallel.

3. An apparatus according to claim 1 wherein each of the light emitting diodes has an area greater than about 1 mm².

4. An apparatus according to claim 1 wherein at least one of the light emitting diodes has an area of about 4 mm².

5. An apparatus according to claim 1 wherein at least one of the light emitting diodes has an area greater than 7 mm².

6. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces between 250 lumens per watt and 270 lumens per watt.

7. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces up to 270 lumens per watt.

8. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 4000 K and 5000 K.

9. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of about 4400 K.

10. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a total drive current of 350 mA or less at room temperature.

11. An apparatus according to claim 1, wherein each of the light emitting diodes has a cross sectional area selected to provide a current density of less than 15 A/cm² at a drive current at which the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 2000 K and 8000 K.

12. An apparatus according to claim 1, wherein each of the light emitting diodes has a cross sectional area selected to provide a current density of less than 10 A/cm² at a drive current at which the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 2000 K and 8000 K.

13. An apparatus according to claim 1, wherein each of the light emitting diodes has a cross sectional area selected to provide a current density of less than 5 A/cm² at a drive current at which the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 2000 K and 8000 K.

14. An apparatus according to claim 1, wherein each of the light emitting diodes has a cross sectional area selected to provide a current density of less than 2.5 A/cm² at a drive current at which the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 2000 K and 8000 K.

15. An apparatus according to claim 1, wherein each of the light emitting diodes has a cross sectional area selected to provide a current density of less than 9 A/cm² at a drive current of about 85 mA at a color temperature of between 2000 K and 8000 K.

16. The apparatus of claim 1, further comprising:

a substrate, wherein the plurality of light emitting diodes are disposed on the substrate;

a transparent outer shell covering the substrate and the light emitting devices and defining a volume of space between the light emitting diodes and the shell; and

an optical material remotely located at least a first distance away from the one or more light emitting devices for affecting light emitted from the one or more light emitting devices.

17. The apparatus of claim 16, wherein the transparent outer shell comprises quartz.

18. The apparatus of claim 17, wherein the optical material is disposed on an inner surface of the transparent outer shell, wherein the optical material is between the plurality of light emitting diodes and the transparent outer shell.

19. The apparatus of claim 17, wherein the transparent outer shell has a diameter greater than or equal to 36 mm.

20. The apparatus of claim 17, wherein the transparent outer shell has a diameter of greater than or equal to 40 mm.

21. The light emitting apparatus of claim 1, wherein light emitted by the light emitting apparatus has a color rendering index of about 80 or more.

22. The light emitting apparatus of claim 1, wherein light emitted by the light emitting apparatus has a color rendering index of about 90 or more.

23. The light emitting apparatus of claim 1, wherein the wavelength conversion material is spaced apart from the plurality of light emitting diodes.

24. The light emitting apparatus of claim 23, wherein the wavelength conversion material is spaced apart from the plurality of light emitting diodes by at least a distance of 1 mm.

25. A light emitting apparatus, comprising:

a substrate;

a plurality of light emitting diodes disposed on the substrate and connected in parallel;

a transparent outer shell covering the substrate and the light emitting devices and defining a volume of space between the light emitting diodes and the shell; and

an optical material remotely located at least a first distance away from the one or more light emitting devices for affecting light emitted from the one or more light emitting devices;

wherein the semiconductor light emitting apparatus produces greater than 250 lumens per watt at a color temperature of between 2000 K and 8000 K.

26. The light emitting apparatus of claim 25, wherein the optical material comprises a phosphor material.

27. The light emitting apparatus of claim 26, wherein the phosphor material is disposed on the transparent outer shell.

28. The light emitting apparatus of claim 26, wherein the phosphor material is coated on an inner or outer surface of the transparent outer shell.

29. The light emitting apparatus of claim 25, wherein light emitted by the light emitting apparatus has a color rendering index of about 80 or more.

30. The light emitting apparatus of claim 25, wherein light emitted by the light emitting apparatus has a color rendering index of about 90 or more.

31. The light emitting apparatus of claim 25, wherein the transparent outer shell has a diameter greater than or equal to 36 mm.

32. The light emitting apparatus of claim 25, wherein the transparent outer shell has a diameter greater than or equal to 40 min.

33. The light emitting apparatus of claim 25, wherein the transparent outer shell comprises quartz.