Patent ID: 8501039

Claim:
A process for production of an oxynitride fluorescent material represented by the following formula (1): (M 1−x R x ) 3−y Si 13−z Al 3+z Al 3+z O 2+u N 21−w (1) in which M is an element selected from the IA group elements, the IIA group elements, the IIIA group elements other than Al, the IIIB group elements, the rare earth elements, and the IVA group elements other than Si; R is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; and x, y, z, u and w are numbers satisfying the conditions of 0<x≦1, −0.1≦y≦0.15, −1≦z≦1, and −1≦u−w≦1.5, respectively; comprising the steps of mixing a nitride or carbide of said element M; a halide of said element M; an oxide, nitride or carbonate of said element R; a nitride, oxide or carbide of Si; and a nitride, oxide or carbide of Al, to prepare a material mixture; firing the material mixture; and then acid-washing the fired product.