Solid state lighting using nanophosphor bearing material that is color-neutral when not excited by a solid state source

• US 8,162,498 B2
• Filed: 03/23/2010
• Issued: 04/24/2012
• Est. Priority Date: 05/27/2008
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Inventors: Ramer, David P., Rains, Jack C. Jr.
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US12/729,887
• Publication Number:
  US 20100172122A1
• Time in Patent Office: 763 Days
• Field of Search: 362/84, 362/85, 362/98, 362501-512, 362/293, 362/311.02, 362/318, 362/231, 362/240, 362/241, 362/249.02
• US Class Current: 362/84
• 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: F21V 14/003 by interposition of elements with electrically controlled variable light transmissivity, e.g. liquid crystal elements or electrochromic devices
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/06 with parabolic curvature
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A solid state lighting device, such as a lamp or light fixture, includes a solid state source and one or more semiconductor nanophosphors dispersed in a light transmissive material in the element. The material is of a type and the nanophosphor(s) are dispersed therein in such a manner that the material bearing the semiconductor nanophosphor(s) is at least substantially color-neutral to the human observer, when the solid state lighting device is off. In some examples, the material appears relatively clear or transparent when the device is off. In other examples, the material appears translucent, e.g. white, when the device is off.

Claims

1. A lighting device, comprising:

a solid state source, containing at least one semiconductor chip within at least one package, for producing electromagnetic energy of a first emission spectrum;

an optical element outside the at least one package of the solid state source and separate from the at least semiconductor chip, arranged to receive electromagnetic energy of the first emission spectrum from the solid state source,

the optical element including;

a semiconductor nanophosphor, wherein;

(a) the semiconductor nanophosphor has an absorption spectrum encompassing at least a substantial portion of the first emission spectrum, and

(b) when excited by electromagnetic energy in the absorption spectrum from the solid state source, the semiconductor nanophosphor emits visible light in a second emission spectrum, for inclusion in a visible light output for the device;

(c) a light transmissive container; and

a material bearing the semiconductor nanophosphor within the container, wherein;

(i) the material is transmissive, at least with respect to energy of the first and second emission spectra,

(ii) the material with the semiconductor nanophosphor dispersed therein appears at least substantially color-neutral when the solid state source is off, and

(iii) the material is a gas or liquid filling an interior volume of a container.

2. The lighting device of claim 1, further comprising a different semiconductor nanophosphor dispersed in the material, wherein:

the different semiconductor nanophosphor has an absorption spectrum encompassing at least a substantial portion of the first emission spectrum,

when excited by electromagnetic energy in the absorption spectrum of the different semiconductor nanophosphor, from the solid state source, the different semiconductor nanophosphor emits visible light in a third emission spectrum that is different from the second emission spectrum, for inclusion in the visible light output from the device,

the second and third emission spectra are separated from the absorption spectra of the nanophosphors,

the material with the semiconductor nanophosphors dispersed therein appears at least substantially color-neutral when the solid state source is off,

the visible light output from the device produced by excitation of the semiconductor nanophosphors is at least substantially white,

the visible light output from the device produced by the excitation of the semiconductor nanophosphors has a color rendering index (CRI) of 75 or higher, and

the visible light output from the device produced by the excitation of the semiconductor nanophosphors has a color temperature in one of the following ranges;

2,725±

145°

Kelvin;

3,045±

175°

Kelvin;

3,465±

245°

Kelvin; and

3,985±

275°

Kelvin.

3. The lighting device of claim 1, wherein:

the solid state source comprises one or more light emitting diodes,

each light emitting diode is rated for producing electromagnetic energy of a wavelength in the range of 460 nm and below, and

the absorption spectrum of the semiconductor nanophosphor has an upper limit at approximately 460 nm or below.

4. The light emitting device of claim 1, wherein the device is configured as a light fixture for a general lighting application to supply illumination in an area intended to be inhabited by a person, the light fixture further comprising a power source.

5. The light emitting device of claim 1, wherein the device is configured as a lamp, the lamp further comprising a bulb.

6. The light emitting device of claim 1, wherein the material bearing the semiconductor nanophosphor appears at least substantially clear when the when the solid state source is off.

7. The light emitting device of claim 1, wherein the material bearing the semiconductor nanophosphor appears at least substantially translucent when the solid state source is off.

8. The lighting device of claim 1, wherein the semiconductor nanophosphor comprises a doped semiconductor nanophosphor.

9. The lighting device of claim 8, wherein:

the material bearing the doped semiconductor nanophosphor is a liquid at least substantially filling the interior volume of the container, and

the lighting device further comprises a bubble in the interior volume of the container with the liquid, the bubble being configured to essentially disappear when the liquid material bearing the semiconductor nanophosphor reaches a nominal operating temperature.

10. The lighting device of claim 8, wherein:

the material bearing the doped semiconductor nanophosphor is a liquid at least substantially filling the interior volume of the container, and

at least a portion of the light transmissive container through which excitation light from the doped semiconductor nanophosphor emerges for an output from the lighting device is at least substantially transparent with respect to visible light.

11. The lighting device of claim 8, wherein:

the material bearing the doped semiconductor nanophosphor is a liquid at least substantially filling the interior volume of the container, and

at least a portion of the light transmissive container through which excitation light from the doped semiconductor nanophosphor emerges for an output from the lighting device is translucent.

12. The lighting device of claim 8, wherein:

the material bearing the doped semiconductor nanophosphor is a gas contained in the interior volume of the container, and

the gas comprises one gas or a combination of gases each selected from the group consisting of;

hydrogen gas, inert gases and hydrocarbon based gases.

13. The lighting device of claim 12, wherein at least a portion of the light transmissive container through which excitation light from the doped semiconductor nanophosphor emerges for an output from the lighting device is at least substantially transparent with respect to energy of the first emission spectrum.

14. The lighting device of claim 12, wherein at least a portion of the light transmissive container through which excitation light from the doped semiconductor nanophosphor emerges for an output from the lighting device is translucent.

15. A lighting device, comprising:

a solid state source, containing at least one semiconductor chip within at least one package, for producing electromagnetic energy of a first emission spectrum;

an optical element outside the at least one package of the solid state source and separate from the at least semiconductor chip, arranged to receive electromagnetic energy of the first emission spectrum from the solid state source,

the optical element including;

a semiconductor nanophosphor, wherein;

(a) the semiconductor nanophosphor has an absorption spectrum encompassing at least a substantial portion of the first emission spectrum, and

(b) when excited by electromagnetic energy in the absorption spectrum from the solid state source, the semiconductor nanophosphor emits visible light in a second emission spectrum, for inclusion in a visible light output for the device;

(c) a light transmissive container; and

a material bearing the semiconductor nanophosphor within the container, wherein;

(i) the material is transmissive, at least with respect to energy of the first and second emission spectra, and

(ii) the material with the semiconductor nanophosphor dispersed therein appears at least substantially color-neutral when the solid state source is off, wherein the material bearing the semiconductor nanophosphor is a solid, wherein;

the solid completely fills an interior volume of a container, or

the solid comprises a silicon included throughout an interior volume of the container.

16. The lighting device of claim 15, further comprising a different semiconductor nanophosphor dispersed in the material, wherein:

the different semiconductor nanophosphor has an absorption spectrum encompassing at least a substantial portion of the first emission spectrum,

when excited by electromagnetic energy in the absorption spectrum of the different semiconductor nanophosphor, from the solid state source, the different semiconductor nanophosphor emits visible light in a third emission spectrum that is different from the second emission spectrum, for inclusion in the visible light output from the device,

the second and third emission spectra are separated from the absorption spectra of the nanophosphors,

the material with the semiconductor nanophosphors dispersed therein appears at least substantially color-neutral when the solid state source is off,

the visible light output from the device produced by excitation of the semiconductor nanophosphors is at least substantially white,

the visible light output from the device produced by the excitation of the semiconductor nanophosphors has a color rendering index (CRI) of 75 or higher, and

the visible light output from the device produced by the excitation of the semiconductor nanophosphors has a color temperature in one of the following ranges;

2,725±

145°

Kelvin;

3,045±

175°

Kelvin;

3,465±

245°

Kelvin; and

3,985±

275°

Kelvin.

17. The lighting device of claim 15, wherein:

the solid state source comprises one or more light emitting diodes,

each light emitting diode is rated for producing electromagnetic energy of a wavelength in the range of 460 nm and below, and

the absorption spectrum of the semiconductor nanophosphor has an upper limit at approximately 460 nm or below.

18. A lighting device, comprising:

a solid state source, containing at least one semiconductor chip within at least one package, for producing electromagnetic energy of a first emission spectrum;

an optical element outside the at least one package of the solid state source and separate from the at least semiconductor chip, arranged to receive electromagnetic energy of the first emission spectrum from the solid state source,

the optical element including;

a semiconductor nanophosphor, wherein;

(a) the semiconductor nanophosphor has an absorption spectrum encompassing at least a substantial portion of the first emission spectrum, and

(b) when excited by electromagnetic energy in the absorption spectrum from the solid state source, the semiconductor nanophosphor emits visible light in a second emission spectrum, for inclusion in a visible light output for the device; and

a material bearing the semiconductor nanophosphor, wherein;

(i) the material is transmissive, at least with respect to energy of the first and second emission spectra, and

(ii) the material with the semiconductor nanophosphor dispersed therein appears at least substantially color-neutral when the solid state source is off, wherein

the semiconductor nanophosphor comprises a quantum dot phosphor,

the optical element further includes a light transmissive container, and

the material bearing the quantum dot phosphor is a liquid at least substantially filling an interior volume of the container.

19. The lighting device of claim 18, further comprising a different semiconductor nanophosphor dispersed in the material, wherein:

the different semiconductor nanophosphor has an absorption spectrum encompassing at least a substantial portion of the first emission spectrum,

when excited by electromagnetic energy in the absorption spectrum of the different semiconductor nanophosphor, from the solid state source, the different semiconductor nanophosphor emits visible light in a third emission spectrum that is different from the second emission spectrum, for inclusion in the visible light output from the device,

the second and third emission spectra are separated from the absorption spectra of the nanophosphors,

the material with the semiconductor nanophosphors dispersed therein appears at least substantially color-neutral when the solid state source is off,

the visible light output from the device produced by excitation of the semiconductor nanophosphors is at least substantially white,

the visible light output from the device produced by the excitation of the semiconductor nanophosphors has a color rendering index (CRI) of 75 or higher, and

the visible light output from the device produced by the excitation of the semiconductor nanophosphors has a color temperature in one of the following ranges;

2,725±

145°

Kelvin;

3,045±

175°

Kelvin;

3,465±

245°

Kelvin; and

3,985±

275°

Kelvin.

20. The lighting device of claim 18, wherein:

the solid state source comprises one or more light emitting diodes,

each light emitting diode is rated for producing electromagnetic energy of a wavelength in the range of 460 nm and below, and

the absorption spectrum of the semiconductor nanophosphor has an upper limit at approximately 460 nm or below.