Green-emitting LED
View Patent ↗Phosphor from the class of the oxynitridosilicates, having a cation M which is doped with divalent europium and having the empirical formula M (1-c) Si 2 O 2 N 2 :D c , where M=Sr or M=Sr (1-x-y) Ba Y Ca x with x+y< 0.5 is used, the oxynitridosilicate completely or predominantly comprising the high-temperature-stable modification HT.
1. A green-emitting LED which is designed as a luminescence conversion LED, comprising:
a primary radiation source, which is a chip emitting a primary radiation in the UV or blue radiation region; and
a layer of a phosphor which is arranged in front of the primary radiation source and completely or partially converts the primary radiation of the chip into a green emission of dominant wavelength λ dom =550 to 570 nm;
wherein the phosphor belongs to a class of oxynitridosilicates, having a cation M and an empirical formula M (1-c) Si 2 O 2 N 2 :D c , where D denotes a doping with divalent europium and where M comprises Sr as a constituent and M=Sr alone or M=Sr (1-x-y) Ba y Ca x with 0≦x+y<0.5 is used, the oxynitridosilicates completely or predominantly comprising a high-temperature-stable modification HT, and the phosphor comprises less than 100 ppm tungsten impurity and less than 100 ppm cobalt impurity.
2. The LED as claimed in claim 1 , wherein the Eu fraction makes up between 0.1 and 20 mol % of M.
3. The LED as claimed in claim 1 , wherein Sr represents a majority of M and a proportion of M is replaced by Ba and/or Ca.
4. The LED as claimed in claim 3 , wherein 30 mol % of M is replaced by Ba and/or Ca.
5. The LED as claimed in claim 1 , wherein a proportion of M is replaced by Li and/or La and/or Zn.
6. The LED as claimed in claim 5 , wherein up to 30 mol % of M is replaced by Li and/or La and/or Zn.
7. The LED as claimed in claim 1 , wherein part of an SiN group in the oxynitridosilicates of formula MSi 2 O 2 N 2 is replaced by an AlO group.
8. The LED as claimed in claim 7 , wherein up to 30 mol % of the SiN group is replaced by the AlO group.
9. The LED as claimed in claim 1 , wherein a proportion of Eu is replaced by Mn.
10. The LED as claimed in claim 9 , wherein up to 30 mol % of Eu is replaced by Mn.
11. The LED as claimed in claim 1 , wherein the primary radiation has a peak wavelength in the range from 380 to 430 nm.
12. The LED as claimed in claim 1 , wherein the green emission has a dominant wavelength in the range from 556 to 564 nm.
13. The LED as claimed in claim 1 , wherein the primary radiation is completely converted.
14. The LED as claimed in claim 1 , wherein the chip is an InGaN chip with a peak emission wavelength in the range from 430 to 465 nm.
15. The LED as claimed in claim 1 , wherein the LED is dimmable.
16. The LED as claimed in claim 1 , wherein a primary radiation has a peak wavelength of at least 380 nm.