Optical system using LED coupled with phosphor-doped reflective materials

• US 7,144,131 B2
• Filed: 09/29/2004
• Issued: 12/05/2006
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: Advanced Optical Technologies, LLC
• Inventors: Rains, Jack C.
• Primary Examiner(s): Cariaso, Alan
• Application Number:
  US10/951,630
• Publication Number:
  US 20060072314A1
• Time in Patent Office: 797 Days
• Field of Search: 362/84, 362/230, 362/231, 362/260
• 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 into a reflective material of an external structure. A disclosed exemplary system, for luminance or illumination applications, utilizes an energy source package, for emitting radiant energy of a first wavelength. The package typically contains an LED or other semiconductor device. A reflector outside the package 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 doped within the reflector to emit visible light, including visible light energy of at least one second wavelength different from the first wavelength. 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 system, for emitting visible light so as to be humanly perceptible, the lighting system comprising:

an energy source package, for emitting radiant energy of a first wavelength;

a reflector outside the energy source package, having a reflective surface arranged to receive radiant energy from the energy source package, wherein the reflective surface exhibits a diffuse reflectivity and forms an optical integrating cavity with an aperture for emission of combined radiant energy;

at least one phosphor doped within the reflector, such that radiant energy of the first wavelength from the energy source package excites the at least one phosphor to emit visible light, comprising visible light energy of at least one second wavelength different from the first wavelength, wherein at least some of visible light emitted by the at least one phosphor is reflected by the reflective surface of the reflector; and

a deflector having an inner reflective surface coupled to the aperture of the optical integrating cavity,

wherein the lighting system directs at least the visible light emitted by the at least one phosphor so that it can be perceived by a person.

2. The lighting system of claim 1, wherein the energy source package comprises a semiconductor device for emitting the radiant energy of the first wavelength and an enclosure for the semiconductor device.

3. The lighting system of claim 2, wherein the semiconductor device comprises a light emitting diode for emitting at least some ultraviolet (UV) radiation.

4. The lighting system of claim 2, wherein the semiconductor device comprises at least one light emitting diode for emitting at least some blue light.

5. The lighting system of claim 1, wherein:

the energy source package includes a source of blue light; and

the system further comprises a source of visible red light and a source of green light arranged to emit at least some visible red light and green light for reflection from the reflective surface of the reflector.

6. The lighting system of claim 1, wherein:

the energy source package includes a source of ultraviolet (UV) radiant energy; and

the system further comprises a source of visible red light, a source of green light and a source of blue light arranged to emit at least some visible red, green and blue light for reflection from the reflective surface of the reflector.

7. A lighting system, for emitting visible light so as to be humanly perceptible, the lighting system comprising:

an energy source package, for emitting radiant energy of a first wavelength;

a reflector outside the energy source package, having a reflective surface arranged to receive radiant energy from the energy source package; and

at least one phosphor doped within the reflector, such that radiant energy of the first wavelength from the energy source package excites the at least one phosphor to emit visible light, comprising visible light energy of at least one second wavelength different from the first wavelength, wherein;

at least some of visible light emitted by the at least one phosphor is reflected by the reflective surface of the reflector, and the lighting system directs at least the visible light emitted by the at least one phosphor so that it can be perceived by a person;

the reflective surface exhibits a diffuse reflectivity;

the reflective surface forms a diffusely reflective cavity having an aperture; and

the lighting system further comprises a mask outside the cavity, having a reflective surface facing toward the aperture of the cavity and arranged to occlude a substantial portion of the aperture.

8. A lighting system for emitting visible light so as to be humanly perceptible, the lighting system comprising:

an energy source package, for emitting radiant energy of a first wavelength;

a reflector outside the energy source package, having a reflective surface arranged to receive radiant energy from the energy source package;

at least one phosphor doped within the reflector, such that radiant energy of the first wavelength from the energy source package excites the at least one phosphor to emit visible light, comprising visible light energy of at least one second wavelength different from the first wavelength,

wherein at least some of visible light emitted by the at least one phosphor is reflected by the reflective surface of the reflector, and the lighting system directs at least the visible light emitted by the at least one phosphor so that it can be perceived by a person; and

a second reflector positioned between the energy source package and a region to be illuminated by the visible light from the system so as to mask view of the energy source package by the person.

9. The lighting system of claim 8, further comprising at least one phosphor doped within the second reflector, such that radiant energy excites the phosphor in the second reflector to emit visible light, comprising visible light energy of a wavelength different from the first wavelength.

10. A lighting system, for emitting visible light so as to be humanly perceptible, the lighting system comprising:

an energy source package, for emitting radiant energy of a first wavelength;

a reflector outside the energy source package, having a reflective surface arranged to receive radiant energy from the energy source package; and

at least one phosphor doped within the reflector, such that radiant energy of the first wavelength from the energy source package excites the at least one phosphor to emit visible light, comprising visible light energy of at least one second wavelength different from the first wavelength,

wherein at least some of visible light emitted by the at least one phosphor is reflected by the reflective surface of the reflector, and the lighting system directs at least the visible light emitted by the at least one phosphor so that it can be perceived by a person, and

wherein the at least one phosphor doped within the reflector comprises;

a first phosphor of a type which is excited by radiant energy of the first wavelength to emit visible light comprising light energy of the second wavelength; and

a second phosphor of a type different from the first type, which is excited to emit visible light comprising light energy of a third wavelength different from the first and second wavelengths.

11. The lighting system of claim 10, wherein the at least one phosphor doped within the reflector further comprises a third phosphor of a type which is excited to emit visible light comprising light energy of a fourth wavelength different from the first, second and third wavelengths.

12. The lighting system of claim 10, wherein the energy source package comprises a semiconductor device for emitting at least some ultraviolet (UV) radiation.

13. The lighting system of claim 10, wherein the energy source package comprises a semiconductor device for emitting at least some blue light.

14. A lighting system, for emitting visible light, the lighting system comprising:

a structure forming an optical integrating cavity comprising a material forming a diffusely reflective inner surface of the cavity and at least one passage for emission of radiant energy integrated by diffuse reflection within the cavity;

a light emitting semiconductor device, coupled for emission of radiant energy comprising a first wavelength into the cavity; and

at least one phosphor doped into the material forming 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 and integration within the cavity so as to be included in light emitted through the at least one passage, wherein;

the light emitting semiconductor device comprises a plurality of light emitting diodes (LEDs);

a first one of the LEDs emits radiant energy of a first character; and

a second one of the LEDs emits radiant energy of a second character, different from the first character.

15. The lighting system of claim 14, wherein:

the a first light emitting diode (LED) is within an enclosure; and

the reflective inner surface of the cavity is outside the enclosure of the first LED.

16. The lighting system of claim 15, wherein the first LED comprises a white, blue or ultraviolet (UV) LED.

17. The lighting system of claim 14 wherein:

the radiant energy from the first LED comprises light of a first color; and

the radiant energy from the second LED comprises light of a second color different from the first color.

18. The lighting system of claim 17, wherein a third one of the LEDs emits radiant energy comprising light of a third color different from the first and second colors.

19. The lighting system of claim 18, wherein at least two of the colors of light are visible colors.

20. The lighting system of claim 18, wherein the system forms a fixture for illuminating an area to be inhabited by a person.

21. The lighting system of claim 18, wherein the system forms a fixture for providing luminance to be observed by a person.

22. The lighting system of claim 14, further comprising a substrate for the cavity, wherein the material forming the diffusely reflective inner surface of the cavity comprises a coating formed on the substrate.

23. The lighting system of claim 14, wherein the material forming the diffusely reflective inner surface of the cavity comprises a substantially white plastic.

24. A lighting system, for emitting visible light, the lighting system comprising:

a structure forming an optical integrating cavity comprising a material forming a diffusely reflective inner surface of the cavity and at least one passage for emission of radiant energy integrated by diffuse reflection within the cavity;

a light emitting semiconductor device, coupled for emission of radiant energy of a first wavelength into the cavity; and

at least one phosphor doped into the material forming 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 and integration within the cavity so as to be included in light emitted through the at least one passage,

wherein the structure forming the optical integrating cavity comprises a base with a diffusely reflective surface and a mask with a reflective surface facing toward the diffusely reflective surface of the base, wherein at least portions of the reflective surfaces of the base and the mask form the reflective inner surface of the optical integrating cavity.

25. The lighting system of claim 24, wherein the reflective surface of the mask is diffusely reflective.

26. A lighting system, for emitting visible light, the lighting system comprising:

a structure forming an optical integrating cavity comprising a material forming a diffusely reflective inner surface of the cavity and at least one passage for emission of radiant energy integrated by diffuse reflection within the cavity;

a light emitting semiconductor device, coupled for emission of radiant energy of a first wavelength into the cavity; and

at least one phosphor doped into the material forming 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 and integration within the cavity so as to be included in light emitted through the at least one passage,

wherein the at least one phosphor doped into the material forming the diffusely reflective inner surface of the cavity comprises;

a first phosphor of a type which is excited by radiant energy of the first wavelength to emit visible light comprising the second wavelength; and

a second phosphor of a type different from the first type, which is excited to emit visible light of a third wavelength different from the first and second wavelengths.

27. The lighting system of claim 26, wherein the at least one phosphor doped into the material forming the diffusely reflective inner surface of the cavity further comprises a third phosphor of a type which is excited to emit visible light of a fourth wavelength different from the first, second and third wavelengths.

28. The lighting system of claim 26, wherein the light emitting semiconductor device comprises a light emitting diode for emitting at least some ultraviolet (UV) radiation.

29. The lighting system of claim 28, wherein the light emitting semiconductor device comprises a light emitting diode for emitting at least some blue light.

30. A method of producing substantially white light for an application visible by a person, the method comprising:

generating light of a first wavelength;

impinging at least a portion of the light of the first wavelength on a diffusely reflective surface of a doped material;

exciting a first phosphor within the doped material with a first portion of the light of the first wavelength impinging on the diffusely reflective surface, so that the first phosphor emits visible light of a second wavelength different from the first wavelength;

exciting a second phosphor within the doped material with radiant energy, so that the second phosphor emits visible light of a third wavelength different from the first and second wavelengths;

diffusely reflecting at least some of the light of the first wavelength from the diffusely reflective surface, so as to combine light of the first wavelength with the light of the and second and third wavelengths to form the substantially white light; and

emitting the substantially white light toward a region intended to be illuminated for the application visible by the person.

31. The method of claims 30, wherein the radiant energy exciting the second phosphor comprises a second portion of the light of the first wavelength impinging on the diffusely reflective surface.

32. The method of claims 30, wherein the radiant energy exciting the second phosphor comprises radiant energy of a wavelength different from the first wavelength.

33. The method of claim 30, wherein the diffusely reflective surface is a surface of an optical integrating cavity.