Lighting fixture using semiconductor coupled with a reflector having reflective surface with a phosphor material

• US 8,356,912 B2
• Filed: 06/16/2009
• Issued: 01/22/2013
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Inventors: Rains, Jack C.
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US12/485,320
• Publication Number:
  US 20090251884A1
• Time in Patent Office: 1,316 Days
• Field of Search: 362/84, 362/230, 362/231, 362/247, 362/260, 362/303, 362/800, 362/241, 362/245, 257/98, 257/100
• US Class Current: 362/231
• CPC Class Codes: F21K 9/62 using mixing chambers, e.g. housings with reflective walls
• 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: F21S 41/37 characterised by their material, surface treatment or coatings
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/0025 Combination of two or more reflectors for a single light source array of reflectors for a cluster of light sources F21V7/0083
• CPC Class Codes: F21V 7/26 the material comprising photoluminescent substances
• CPC Class Codes: F21V 7/30 the coatings comprising photoluminescent substances
• CPC Class Codes: F21V 9/08 for producing coloured light, e.g. monochromatic; for reducing intensity of light with provision for controlling the colour F21V9/40
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

To improve semiconductor-based systems for generating white light, a phosphor is integrated with an external structure, such as a reflector. A disclosed exemplary system, for illumination applications, utilizes one or more semiconductor devices for emitting radiant energy of a first wavelength. A reflector outside the package of the LED or other semiconductor device has a reflective surface arranged to receive radiant energy from the energy source. At least some of the received radiant energy of the first wavelength excites one or more phosphors associated with an external light processing element, for example, located along the surface of the reflector, to emit light, including visible light energy of at least one second wavelength different from the first wavelength. In the examples, at least some of visible light emitted by the phosphor is reflected by the reflective surface of the reflector and directed to facilitate the particular humanly perceptible luminance or illumination application.

Claims

1. A lighting fixture for emitting visible light and adapted to provide lighting in an area to be inhabited by a person, the lighting fixture comprising:

a structure forming an optical integrating cavity, the optical integrating cavity comprising;

a diffusely reflective inner surface of the cavity; and

at least one optical passage through a diffusely reflective wall of the cavity for emission of radiant energy integrated by diffuse reflection within the cavity;

a plurality of light emitting diodes (LED), each LED comprising an enclosure and a semiconductor chip contained within the enclosure, each LED coupled for emission of radiant energy into the cavity, at least one of the LEDs emitting radiant energy of a first wavelength; and

a coating layer containing at least one phosphor, extending across a substantial portion of the diffusely reflective inner surface of the cavity, the at least one phosphor being of a type excited by radiant energy of the first wavelength for emission of visible light of at least one second wavelength different from the first wavelength for reflection,

wherein the diffusely reflective inner surface of the cavity is outside the enclosures of the LEDs.

2. The lighting fixture of claim 1, wherein the at least one LED comprises a white, blue, ultraviolet (UV) or near UV LED.

3. The lighting fixture of claim 2, wherein the at least one LED comprises a blue LED.

4. The lighting fixture of claim 1, wherein the fixture is adapted to provide luminance to be observed by a person.

5. The lighting fixture of claim 1, wherein the coating layer comprises a paint.

6. The lighting fixture of claim 5, wherein the diffusely reflective inner surface of the cavity is comprised of a plastic material.

7. The lighting fixture of claim 1, further comprising a deflector having an inner reflective surface coupled to the optical passage of the optical integrating cavity.

8. The lighting fixture of claim 1, wherein the at least one phosphor being of the type excited by radiant energy of the first wavelength for emission of visible light of the at least one second wavelength different from the first wavelength for integration within the cavity so as to be included in light emitted through the at least one optical passage.

9. The lighting fixture of claim 1, wherein the optical passage comprises a diffuser.

10. A lighting fixture for emitting visible light and adapted to provide lighting in an area to be inhabited by a person, the lighting fixture comprising:

a structure forming an optical integrating cavity, the optical integrating cavity comprising;

a plurality of diffusely reflective walls forming inner surfaces of the cavity; and

at least one optical passage for emission of radiant energy integrated by diffuse reflection within the cavity;

a plurality of white light emitting diodes (LED), at least one UV or near UV LED, each LED comprising an enclosure and a semiconductor chip contained within the enclosure, each LED coupled for emission of radiant energy into the cavity, the at least one UV or near UV LED emitting radiant energy of a first wavelength; and

at least one phosphor doped within a substantial portion of an inner surface of at least one of the diffusely reflective walls of the cavity, the at least one phosphor being of a type excited by radiant energy of the first wavelength for emission of visible light of at least one second wavelength different from the first wavelength for reflection,

wherein the diffusely reflective walls of the cavity are outside the enclosures of the LEDs.

11. The lighting fixture of claim 10, wherein the fixture is adapted to provide luminance to be observed by a person.

12. The lighting fixture of claim 10, wherein the plurality of diffusely reflective walls comprise a plastic material.

13. The lighting fixture of claim 10, further comprising a deflector having an inner reflective surface coupled to the optical passage of the optical integrating cavity.

14. The lighting fixture of claim 10, wherein the at least one phosphor being of the type excited by radiant energy of the first wavelength for emission of visible light of the at least one second wavelength different from the first wavelength for integration within the cavity so as to be included in light emitted through the at least one optical passage.

15. The lighting fixture of claim 10, wherein the optical passage comprises a diffuser.

16. A lighting fixture for emitting visible light and adapted to provide lighting in an area to be inhabited by a person, the lighting fixture comprising:

a structure forming an optical integrating cavity, the optical integrating cavity comprising;

a diffusely reflective inner surface of the optical integrating cavity; and

at least one optical passage through a diffusely reflective wall of the optical integrating cavity for emission of radiant energy integrated by diffuse reflection within the optical integrating cavity;

a plurality of light emitting diodes (LED), each LED comprising an enclosure and a semiconductor chip contained within the enclosure, each LED coupled for emission of radiant energy into the optical integrating cavity, and all of the LEDs are of a single type selected from the group consisting of;

white, blue, ultraviolet (UV) and near UV LED; and

a coating layer containing at least one phosphor, extending across a substantial portion of the diffusely reflective inner surface of the cavity,

wherein at least some of the radiant energy passes through the coating layer and excites the at least one phosphor to emit visible light for emission from the at least one optical passage,

wherein the diffusely reflective inner surface of the cavity is outside the enclosures of the LEDs.

17. The lighting fixture of claim 16, wherein each of the plurality of LEDs comprises a blue LED.

18. The lighting fixture of claim 16, wherein the fixture is adapted to provide luminance to be observed by a person.

19. The lighting fixture of claim 16, wherein the coating layer comprises a paint.

20. The lighting fixture of claim 19, wherein the diffusely reflective inner surface of the cavity is comprised of a plastic material.

21. The lighting fixture of claim 16, further comprising a deflector having an inner reflective surface coupled to the optical passage of the optical integrating cavity.

22. The lighting fixture of claim 16, wherein the optical passage comprises a diffuser.

23. The lighting fixture of claim 16, wherein the radiant energy passes through the coating layer to the diffusely reflective inner surface and excites the at least one phosphor to emit visible light, the visible light passing back through the coating layer before emission through the at least one optical passage.

24. A lighting fixture for emitting visible light and adapted to provide lighting in an area to be inhabited by a person, the lighting fixture comprising:

a structure forming an optical integrating cavity, the optical integrating cavity comprising;

a plurality of walls forming inner surfaces of the cavity; and

at least one optical passage for emission of radiant energy integrated by diffuse reflection within the cavity;

a plurality of white light emitting diodes (LED), at least one UV or near UV LED, each LED comprising an enclosure and a semiconductor chip contained within the enclosure, each LED coupled for emission of radiant energy into the cavity, the at least one UV or near UV LED emitting radiant energy of a first wavelength; and

at least one phosphor doped within a substantial portion of an inner surface of at least one of the walls of the cavity, the at least one phosphor being of a type excited by radiant energy of the first wavelength for emission of visible light of at least one second wavelength different from the first wavelength for reflection,

wherein the walls of the cavity are outside the enclosures of the LEDs.

25. A lighting fixture for emitting visible light and adapted to provide lighting in an area to be inhabited by a person, the lighting fixture comprising:

a plurality of sources for supplying radiant energy, each energy source comprising a package and a light emitting diode (LED) semiconductor chip enclosed within the package,

wherein at least one of the sources supplies radiant energy of a first wavelength;

a macro reflector outside of and external to the packages of said energy sources, the macro reflector having a diffusely reflective inner surface forming an optical integrating cavity,

wherein the energy sources are coupled to supply radiant energy emitted by the LED semiconductor chips into said optical integrating cavity formed by the diffusely reflective inner surface of the macro reflector; and

at least one phosphor associated with a portion of a wall of said optical integrating cavity formed by the macro reflector at a location to receive at least some of the radiant energy of the first wavelength, wherein;

the at least one phosphor is of a type for excitation by radiant energy of the first wavelength to emit visible light, comprising visible light of at least one second wavelength different from the first wavelength, and

the macro reflector and at least one phosphor are configured for inclusion of at least some of the visible light emitted by the at least one phosphor in an optically integrated visible light emission of the fixture from the macro reflector.

26. The lighting fixture of claim 25, wherein the fixture is adapted to provide luminance to be observed by a person.

27. The lighting fixture of claim 25, wherein the at least one phosphor is included as a coating layer in the form of a paint.

28. The lighting fixture of claim 25, wherein the diffusely reflective inner surface of the cavity is comprised of a plastic material.