Lighting device

Patent metadata

Field	Value
Publication number	US-11767470-B2
Application number	US-202017433535-A
Country	US
Kind code	B2
Filing date	Feb 17, 2020
Priority date	Feb 26, 2019
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A lighting device for adjusting the color temperature of white light emitted by a luminescent material is disclosed. The lighting device comprises: a luminescent material configured to emit white light when being exposed to electromagnetic radiation of a preselected wavelength range; at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a first wavelength range selected from the range of 230-330 nm; at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a second wavelength range, different from the first wavelength range, selected from the range of 300-600 nm; a metering unit configured to adjust the ratio of the irradiances of electromagnetic radiation of first wavelength range and of electromagnetic radiation of second wavelength range that is exposed on the luminescent material.

First claim

The invention claimed is:

1. A lighting device for adjusting the color temperature of white light emitted by a luminescent material, wherein the lighting device comprises:
a luminescent material configured to emit white light when being exposed to electromagnetic radiation of a preselected wavelength range;
at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a first wavelength range selected from the range of 230-330 nm;
at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a second wavelength range, different from the first wavelength range, selected from the range of 300-600 nm;
a metering unit configured to adjust the ratio of the irradiances of electromagnetic radiation of first wavelength range and of electromagnetic radiation of second wavelength range that is exposed on the luminescent material for adjusting the color temperature of white light emitted by the luminescent material as a result of being subjected to the electromagnetic radiation of the preselected wavelength range;
wherein the luminescent material is represented by the following formula (I)
(M′) 8 (M″M″′) 6 O 24 (X,X′) 2 :M″″  formula (I)

wherein
M′ represents a monoatomic cation of an alkali metal selected from Group 1 of the IUPAC periodic table of the elements, or any combination of such cations;
M″ represents a trivalent monoatomic cation of an element selected from Group 13 of the IUPAC periodic table of the elements, or of a transition element selected from any of Groups 3-12 of the IUPAC periodic table of the elements, or any combination of such cations;
M′″ represents a monoatomic cation of an element selected from Group 14 of the IUPAC periodic table of the elements, or of an element selected from any of Groups 13 and 15 of the IUPAC periodic table of the elements, or of Zn, or any combination of such cations;
X represents an anion of an element selected from Group 17 of the IUPAC periodic table of the elements, or any combination of such anions, or wherein X is absent;
X′ represents an anion of an element selected from Group 16 of the IUPAC periodic table of the elements, or any combination of such anions, or wherein X′ is absent; and
M″″ represents a dopant cation of an element selected from transition metals of the IUPAC periodic table of the elements, or of TI, Pb, or Bi, or any combination of such cations, or wherein M″″ is absent;
with the proviso that at least one of X and X′ is present.

2. The lighting device of claim 1 , wherein the difference between the first wavelength range and the second wavelength range is at least 20 nm.

3. The lighting device of claim 1 , wherein the electromagnetic radiation of the first wavelength range is selected from the range of 260-320 nm.

4. The lighting device of claim 1 , wherein the electromagnetic radiation of the second wavelength range is selected from the range of 330-400 nm.

5. The lighting device of claim 1 , wherein the metering unit is configured to adjust the ratio of the irradiances of electromagnetic radiation of first wavelength range and of electromagnetic radiation of second wavelength range that is exposed on the luminescent material by adjusting the amount of electric current fed to the at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a first wavelength range and to the at least one second excitation unit configured to expose the luminescent material to electromagnetic radiation of a second wavelength range.

6. The lighting device of claim 1 , wherein the color temperature of white light emitted by the luminescent material is adjusted within the range of 2000-13000 K.

7. A method for adjusting the color temperature of white light emitted by a luminescent material, wherein the method comprises:
providing a luminescent material represented by the formula (I) as defined in claim 1 ;
subjecting the luminescent material to electromagnetic radiation with at least one excitation unit exposing the luminescent material to electromagnetic radiation of a first wavelength range selected from the range of 230-330 nm, and with at least one excitation unit exposing the luminescent material to electromagnetic radiation of a second wavelength range, different from the first wavelength range, selected from the range of 300-600 nm,
wherein the ratio of the irradiances of electromagnetic radiation of first wavelength range and of electromagnetic radiation of second wavelength range that is exposed on the luminescent material is adjusted for adjusting the color temperature of white light emitted by the luminescent material as a result of being subjected to the electromagnetic radiation.

8. The method of claim 7 , wherein the difference between the first wavelength range and the second wavelength range is at least 20 nm.

9. The method of claim 7 , wherein the electromagnetic radiation of the first wavelength range is selected from the range of 260-320 nm.

10. The method of claim 7 , wherein the electromagnetic radiation of the second wavelength range is selected from the range of 330-400 nm.

11. The method of claim 7 , wherein the method comprises adjusting the ratio of the irradiances of electromagnetic radiation of first wavelength range and of electromagnetic radiation of second wavelength range that is exposed on the luminescent material by adjusting the amount of electric current fed to the at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a first wavelength range and to the at least one excitation unit configured to expose the luminescent material to electromagnetic radiation of a second wavelength range.

12. The method of claim 7 , wherein the color temperature of white light emitted by the luminescent material is adjusted within the range of 2000-13000 K.

Assignees

• Turun Yliopisto

Inventors

• Lastusaari Mika
• Norrbo Isabella

Classifications

• C09K11/7734

  Aluminates · CPC title

• C09K11/676 Primary

  Aluminates; Silicates · CPC title

• C09K11/77344

  Aluminosilicates · CPC title

• C09K11/77744

  Aluminosilicates · CPC title

• F21V9/30

  Elements containing photoluminescent material distinct from or spaced from the light source (shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40) · CPC title