Patent ID: 7258818

Claim:
A method for producing a sialon-based phosphor, comprising mixing a silicon nitride raw material powder with an AlN-containing substance acting as an aluminum source, an oxide of metal M (wherein M is at least one metal selected from Ca, Mg, Y and Li) or a precursor substance to an oxide of metal M upon thermal decomposition, and an oxide of lanthanide metal Ln or a precursor substance to an oxide of lanthanide metal Ln upon thermal decomposition, and firing the mixture at 1,400 to 2,000° C. in an inert gas atmosphere containing nitrogen to produce an α-sialon based phosphor represented by the formula: M x Ln y Si 12−(m+n) Al (m+n) O n N 16−n wherein M is at least one metal selected from Ca, Mg, Y and Li, Ln is at least one lanthanide metal selected from Eu, Dy, Er, Tb, Yb and Ce, ax+by=m (assuming that the valence of metal M is a and the valence of lanthanide metal Ln is b), O<x≦1.5, 0.3≦m<4.5, and 0<n<2.25, wherein said silicon nitride raw material powder comprises amorphous silicon nitride and crystalline silicon nitride.