Highly efficient stable oxynitride phosphor
View Patent ↗Phosphor from the class of the oxynitridosilicates, having a cation M which is doped with divalent europium, and having the empirical formula MSi 2 O 2 N 2 , where M=Sr 1-x-y Ca y Eu x where 0.3≦x+y≦0.725, with a Ca/Eu ratio of >1, the oxynitridosilicate having an emission with a dominant wavelength in the range from 555 to 568 nm.
1. A light source having a primary radiation source, which emits radiation in the short-wave region of the optical spectral region in the wavelength range from 140 to 480 nm, this radiation being partly or completely converted into secondary radiation with a longer wavelength in the visible spectral region by means of at least one first phosphor; wherein the first phosphor is a highly efficient, stable oxynitride phosphor from the class of the oxynitridosilicates with a cation M and the empirical formula Msi 2 O 2 N 2 ; M simultaneously comprises as constituent Sr and Ca and also an activator D; D includes at least divalent europium; M=Sr 1-x-y Ca y Eu x where 0.3≦x+y≦0.725, with a Ca/Eu ratio of >1; and the first phosphor has an emission with a dominant wavelength in the range from 555 to 568 nm.
2. The light source as claimed in claim 1 , wherein the primary radiation source used is a light-emitting diode based on InGaN or InGaAlP or a discharge lamp working on a low pressure or high pressure basis or an electroluminescent lamp.
3. The light source as claimed in claim 1 , wherein some of the primary radiation is also converted into radiation with a longer wavelength by means of a second phosphor.
4. The light source as claimed in claim 3 , wherein some of the primary radiation is also converted into radiation with a longer wavelength by means of a third phosphor, this third phosphor emitting in the red spectral region.
5. The light source as claimed in claim 2 , wherein the discharge lamp has an indium-containing fill.
6. The light source as claimed in claim 3 , wherein the first and second phosphors are selected and mixed in a suitable way to generate white light.
7. The light source of claim 1 , wherein M comprises between 1 and 20 mol % Eu.
8. The light source of claim 1 , wherein M comprises between 2 and 12 mol % Eu.
9. The light source of claim 1 , wherein y is ≧0.475.
10. The light source of claim 1 , wherein the Ca/Sr ratio is in the range 0.90<Ca/Sr<2.30.
11. The light source of claim 1 , wherein the Ca/Sr ratio is in the range 0.95<Ca/Sr<1.20.
12. The light source of claim 1 , wherein a part of Eu is replaced by Mn.
13. The light source of claim 1 , wherein up to 30 mol % is replaced by Mn.