Patent ID: 8680547

Claim:
Light emitting device comprising a light source, especially a LED, and a luminescent material which is a ceramic multiphase material essentially of the composition M 2−z Ce z Si 5−x−y−(z−z1) A y+(z−z1) N 8−4x−y+z1 O 4x+y−z1 wherein: M is selected out of the group comprising Sr, Ca, Ba, Mg, Eu or mixtures thereof, A is selected out of the group comprising Al, B, Ga or mixtures thereof, x is ≧0 to ≦0.5, y is ≧0 to ≦4, z is ≧0 to ≦1 and z 1 is ≧0 to ≦z, the ceramic multiphase material comprises a main phase and an additional phase, wherein the main phase is crystallographically distinguishable from the additional phase and the main phase and the additional phase are present in the multiphase material as grains, the main phase comprises one of M 2−z Ce z Si 5−a−(z−z1) A a+(z−z1) N 8−a+z1 O a−z1 and Ba b M I 2−b−z Ce z Si 5−a−(z−z1) A a+(z−z1) N 8−a+z1 O a−z1 ; a is from ≧0 to ≦4, b is from ≧0 to ≦1, and M I is one of Sr, Ca, Mg, Eu, or mixtures thereof; a volume content of the main phase in the material is ≦70%; the additional phase comprises one of M 2 Si 7 N 10 and M 2 SiO 4 ; and a volume content of the additional phase is ≦15%.