Illumination system comprising a radiation source and fluorescent material
View Patent ↗The invention concerns an illumination system comprising a radiation source and a fluorescent material comprising at least one phosphor capable of absorbing part of the light emitted by the radiation source and emitting light of a wavelength different from that of the absorbed light; wherein said at least one phosphor is a yellow to red-emitting europium(II) activated halogeno-oxonitridosilicate of the general formula Ea x Si y N 2/3X+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001≦z≦0.09, 0.005<a≦5 0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine. The invention is also concerned with a red to yellow-emitting europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea x Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine, and a method of manufacturing same.
1. Illumination system comprising a radiation source and a fluorescent material comprising at least one phosphor capable of absorbing part of the light emitted by the radiation source and emitting light of a wavelength different from that of the absorbed light, wherein said at least one phosphor is a europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine.
2. Illumination system according to claim 1 , wherein the radiation source is a light emitting diode.
3. Illumination system according to claim 1 , wherein the radiation source is selected from the light emitting diodes having an emission with a peak wavelength in the range of 400 to 480 nm and wherein the fluorescent material comprises a europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine.
4. Illumination system according to claim 1 , wherein the radiation source is selected from the light emitting diodes having an emission with a peak wavelength in the range of 400 to 480 nm and the fluorescent material comprises a europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine and a second phosphor.
5. Illumination system according to claim 4 , wherein the second phosphor is a red phosphor selected from the group comprising (Ca 1−x Sr x )S:Eu, wherein 0≦x≦1 and (Sr 1−x−y Ba x Ca y ) 2−z Si 5−a Al a N 8−a O a :Eu z , wherein 0≦a<5, 0<x≦1, 0≦y≦1 and 0<z≦0.09.
6. Illumination system according to claim 4 , wherein the second phosphor is a green phosphor selected from the group comprising (Ba 1 — x Sr x ) 2 SiO 4 :Eu, wherein 0≦x≦1, SrGa 2 S 4 :Eu, SrSi 2 N 2 O 2 :Eu, Ln 3 Al 5 O 12 :Ce and YAG-Ce.
7. Illumination system according to claim 1 , wherein the radiation source is selected from the light emitting diodes having an emission with a peak wavelength in the UV range of 200 to 420 nm and wherein the fluorescent material comprises a europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine.
8. Illumination system according to claim 1 , wherein the radiation source is selected from the light emitting diodes having an emission with a peak wavelength in the UV-range of 200 to 420 nm and wherein the fluorescent material comprises europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine and a second phosphor.
9. Illumination system according to claim 8 , wherein the second phosphor is a blue phosphor selected from the group comprising BaMgAl 10 O 7 :Eu, Ba 5 SiO 4 (Cl,Br) 6 :Eu, CaLn 2 S 4 :Ce, (Sr,Ba,Ca) 5 (PO 4 ) 3 Cl:Eu and LaSi 3 N 5 :Ce.
10. Illumination system according to claim 8 , wherein the second phosphor is a red phosphor selected from the group comprising Ca 1−x Sr x )S:Eu, wherein 0≦x≦1 and (Sr 1−x−y Ba x Ca y ) 2−z Si 5−a Al a N 8−a O a :Eu z , wherein 0≦a<5, 0≦x≦1, 0≦y≦1 and 0<z≦0.09.
11. Illumination system according to claim 8 , wherein the second phosphor is a yellow to green phosphor selected from the group comprising (Ba 1 — x Sr x ) 2 SiO 4 :Eu, wherein 0≦x≦1, SrGa 2 S 4 Eu, SrSi 2 N 2 O 2 :Eu, Ln 3 Al 5 O 12 :Ce and YAG-Ce.
12. Phosphor capable of absorbing part of the light emitted by the radiation source and emitting light of a wavelength different from that of the absorbed light, wherein said phosphor is a europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine.
13. Phosphor according to claim 12 , wherein said phosphor additionally comprises a co-activator selected from the group comprising ytterbium and samarium.
14. Phosphor according to claim 12 , wherein said phosphor is a europium-activated halogeno-oxonitridosilicate of the general formula Ea 2 Si 5 N 8 :Eu z O a F b , wherein 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group comprising calcium and strontium.
15. Phosphor according to claim 12 , wherein the phosphor has a coating selected from the group comprising fluorides and orthophosphates of the elements aluminum, scandium, yttrium, lanthanum gadolinium and lutetium, the oxides of aluminum, yttrium and lanthanum and the nitride of aluminum.
16. A method for preparing europium(II)-activated halogeno-oxonitridosilicate of the general formula Ea X Si y N 2/3x+4/3y :Eu z O a X b , wherein 1≦x≦2; 3≦y≦7; 0.001<z≦0.09, 0.005<a≦0.05, 0.01<b≦0.3, EA is at least one earth alkaline metal chosen from the group comprising calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine, said method comprising: a) mixing starting materials from at least one oxygen-containing alkaline earth precursor compound, at least one silicon nitrogen compound selected from the group comprising silicon nitride and silicon diimide, at least one europium precursor compound and a reducing compound selected from the group comprising carbon and silicon, to prepare a mixture, and b) transferring the resulting mixture into a closed reactor and heat-treating the mixture under a reduced atmosphere of a mixed gas, composed of nitrogen and hydrogen.
17. The method of claim 16 , wherein the oxygen-containing alkaline earth precursor compound is a carbonate.
18. The method of claim 16 , wherein the starting material comprises also a flux, selected from the halide of the earth alkaline metals.
19. The method of claim 16 , wherein the europium precursor compound is a halide, selected from the group comprising europium fluoride, europium chloride, europium bromide and europium iodide.
20. The method of claim 16 , wherein the europium precursor compound is a europium(II)-doped earth alkaline metal oxide.
21. The method of claim 1 , wherein the heat-treating temperature ranges from 1,300 to 1,700° C.