| 主权项 |
1. A process of making a high-efficiency phosphor from the class of oxynitridosilicates with a cation M2+ and an empirical formula M(1-c)SiO2N2:Dc, where M2+ simultaneously contains as constituents Sr2+ and Ba2+, and where D is a divalent dopant with at least europium, wherein Sr(1-x)Bax, where 0.45≦x≦0.55, is used for M, the oxynitridosilicate completely or predominantly comprising a mixed sion phase which corresponds neither to that of pure Sr sion phase nor that of pure Ba sion phase, the dominant wavelength of the mixed sion phase with the given doping content being shifted by at least 6 nm, with respect to the dominant wavelength of the pure Sr sion phase with the same doping content towards longer wavelengths, wherein the europium makes up from 5 to 12 mol % of M, wherein the process comprises:
1) mixing carbonates of Sr and of Ba intensively together with SiO2 and a flux as well as with an Eu precursor, 2) annealing the mixture obtained in step 1) to synthesize an orthosilicate, 3) mixing the orthosilicate with a substantially stoichiometric batch of Si3N4, and 4) annealing the mixture obtained in step 3) in a slightly reducing atmosphere. |
