Ultra-high efficacy semiconductor light emitting devices

• US 9,052,416 B2
• Filed: 04/15/2011
• Issued: 06/09/2015
• 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: Edmond, John Adam, Hussell, Christopher P.
• Primary Examiner(s): Ho, Anthony
• Application Number:
  US13/087,510
• Publication Number:
  US 20110310587A1
• Time in Patent Office: 1,516 Days
• Field of Search: 313/488, 257/79, 257/E33.001
• US Class Current: 1/1
• 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 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• 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 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• 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 includes an elongated hollow wavelength conversion tube that comprises an elongated wavelength conversion tube wall having wavelength conversion material such as phosphor dispersed therein uniformly or non-uniformly. The tube need not be cylindrical. A semiconductor light emitting device is oriented to emit light inside the elongated hollow wavelength conversion tube to impinge upon the elongated wavelength conversion tube wall and the wavelength conversion material dispersed therein.

Claims

1. A semiconductor light emitting apparatus comprising:

a wavelength conversion element comprising wavelength conversion material;

a light emitting diode that is oriented to emit light to impinge upon the wavelength conversion element, wherein the wavelength conversion element is remote from the light emitting diode; and

an optical surface between the light emitting diode and the wavelength conversion element that passes substantially all of the light emitted from the light emitting diode,

wherein the semiconductor light emitting apparatus produces light that has passed through the wavelength conversion element such that the apparatus is capable of producing light between 150 and 208 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 diode comprises a blue light emitting diode.

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

4. An apparatus according to claim 1 wherein the light emitting diode has an area of about 3 mm².

5. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a color temperature of between 4000 K and 5000 K.

6. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a color temperature of about 4600 K.

7. An apparatus according to claim 1 wherein the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a drive current of 350 mA at room temperature.

8. An apparatus according to claim 1, wherein the light emitting diode has a cross sectional area selected to provide a current density of less than 30 A/cm² at a drive current at which the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a color temperature of between 2000 K and 8000 K.

9. An apparatus according to claim 1, wherein the light emitting diode has a cross sectional area selected to provide a current density of less than 20 A/cm² at a drive current at which the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a color temperature of between 2000 K and 8000 K.

10. An apparatus according to claim 1, wherein the light emitting diode 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 between 200 and 208 lumens per watt at a color temperature of between 2000 K and 8000 K.

11. An apparatus according to claim 1 wherein the wavelength conversion element comprises an elongated hollow wavelength conversion tube that comprises an elongated wavelength conversion tube wall;

and

wherein the semiconductor light emitting device is oriented to emit light inside the elongated hollow wavelength conversion tube to impinge upon the elongated wavelength conversion tube wall.

12. An apparatus according to claim 11 wherein the semiconductor light emitting device is oriented such that at least about 20% of the emitted light strikes the elongated wavelength conversion tube wall at an oblique angle.

13. An apparatus according to claim 11 wherein the semiconductor light emitting device is oriented such that at least about 90% of the emitted light strikes the elongated wavelength conversion tube wall at an oblique angle.

14. An apparatus according to claim 11 wherein the semiconductor light emitting device is a blue light emitting diode having an area greater than 1 mm² and wherein the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a color temperature between 4000 K and 8000 K.

15. An apparatus according to claim 14 wherein the semiconductor light emitting apparatus produces between 200 and 208 lumens per watt at a color temperature of about 4600 K.

16. An apparatus according to claim 11 wherein the wavelength conversion material is dispersed in the elongated hollow wavelength conversion tube and wherein the elongated hollow wavelength conversion tube is oriented relative to the semiconductor light emitting device so as to provide a longer path length through the elongated wavelength conversion tube wall for light that is emitted by the semiconductor light emitting device that does not strike the wavelength conversion material embedded therein without increasing the path length of light that is converted by striking the wavelength conversion material embedded therein.

17. An apparatus according to claim 11 wherein the tube wall defines a tube axis, wherein the semiconductor light emitting device is configured to emit light symmetrically about an emission axis and wherein the semiconductor light emitting device is oriented such that the emission axis is coincident with the tube axis.

18. An apparatus according to claim 11 wherein the elongated hollow wavelength conversion tube includes first and second opposing ends, and the semiconductor light emitting device is adjacent the first end.

19. An apparatus according to claim 18 wherein the second end is a closed second end.

20. An apparatus according to claim 19 wherein the second end is a crimped second end.

21. An apparatus according to claim 19 further comprising a cap at the second end.

22. An apparatus according to claim 21 wherein the cap comprises wavelength conversion material.

23. An apparatus according to claim 21 wherein the cap comprises reflective material.

24. An apparatus according to claim 18 wherein the semiconductor light emitting device is a first semiconductor light emitting device, the apparatus further comprising a second semiconductor light emitting device adjacent the second end that is oriented to emit light inside the elongated hollow wavelength conversion tube to impinge upon the elongated wavelength conversion tube wall and the wavelength conversion material dispersed therein.

25. An apparatus according to claim 24 further comprising a double-sided reflector in the elongated hollow wavelength conversion tube between the first and second semiconductor light emitting devices.

26. An apparatus according to claim 24 wherein the elongated hollow wavelength conversion tube is crimped between the first and second semiconductor light emitting devices.

27. An apparatus according to claim 11 wherein the semiconductor light emitting device extends at least partially into the elongated hollow wavelength conversion tube.

28. An apparatus according to claim 27 wherein the elongated hollow wavelength conversion tube includes first and second opposing ends and wherein the semiconductor light emitting device extends at least partially into the wavelength conversion tube to emit light towards the first end.

29. An apparatus according to claim 28 wherein the semiconductor light emitting device is a first semiconductor light emitting device, the apparatus further comprising a second semiconductor light emitting device that extends at least partially into the elongated hollow wavelength conversion tube to emit light towards the second end.

30. An apparatus according to claim 29 wherein the first and second semiconductor light emitting devices are oriented in back-to-back relation within the elongated hollow wavelength conversion tube.

31. An apparatus according to claim 29 further comprising:

a screw-type base;

a pair of standoffs that maintain the elongated hollow wavelength conversion tube and the first and second semiconductor light emitting devices spaced apart from the base; and

a bulb that is connected to the screw-type base and surrounds the hollow wavelength conversion tube and the first and second semiconductor light emitting devices.

32. An apparatus according to claim 11 wherein the elongated hollow wavelength conversion tube is a first elongated hollow wavelength conversion tube, the apparatus further comprising a second elongated hollow wavelength conversion tube, wherein the first and second elongated hollow wavelength conversion tubes share a common end and wherein the semiconductor light emitting device is adjacent the common end and is oriented to emit light inside the first and second elongated hollow wavelength conversion tubes.

33. An apparatus according to claim 32 further comprising a plurality of elongated hollow wavelength conversion tubes that share the common end and extend around a central axis.

34. An apparatus according to claim 11 wherein the elongated hollow wavelength conversion tube wall includes inner and outer surfaces and wherein the elongated hollow wavelength conversion tube further comprises a supporting layer on the inner surface and/or on the outer surface.

35. An apparatus according to claim 11 wherein the elongated hollow wavelength conversion tube is a first elongated hollow wavelength conversion tube, the apparatus further comprising:

a second elongated hollow wavelength conversion tube that comprises a second elongated wavelength conversion tube wall having wavelength conversion material dispersed therein, the first and second elongated hollow wavelength conversion tubes being coaxial to one another.

36. An apparatus according to claim 11 wherein the elongated tube wall includes inner and outer surfaces and wherein the inner and/or outer surfaces are textured.

37. An apparatus according to claim 36 wherein the inner and/or outer surfaces are non-uniformly textured.

38. An apparatus according to claim 11 wherein the elongated tube wall has wavelength conversion material non-uniformly dispersed therein.

39. An apparatus according to claim 11 further comprising:

a mounting substrate; and

a dome on the mounting substrate;

wherein the semiconductor light emitting device is located between the mounting substrate and the dome; and

wherein the dome extends at least partially into an end of the elongated hollow wavelength conversion tube and the mounting substrate extends at least partially outside the elongated hollow wavelength conversion tube.

40. An apparatus according to claim 1, wherein the wavelength conversion element comprises a first wavelength conversion material and a second wavelength conversion material.

41. An apparatus according to claim 1, wherein the wavelength conversion element further comprises an inner surface including the first wavelength conversion material and an outer surface including the second wavelength conversion material.

42. An apparatus according to claim 1, wherein the wavelength conversion element further comprises an inner surface and/or an outer surface that are textured to enhance scattering of the light emitted from the light emitting diode.

43. An apparatus according to claim 42, where the inner surface and/or the outer surface are textured in a sawtooth pattern.

44. An apparatus according to claim 1, wherein the semiconductor light emitting apparatus produces light that is between 160 and 208 lumens per watt at a color temperature of between 2000 K and 8000 K.

45. An apparatus according to claim 1, wherein the semiconductor light emitting apparatus produces light that is between 170 and 208 lumens per watt at a color temperature of between 2000 K and 8000 K.