Patent ID: 8277686

Claim:
Sialon phosphor particles 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 the group consisting of Li, Ca, Mg and Y, Ln is a lanthanide metal containing at least Eu, and assuming that the valence of the metal M is a and the valence of the lanthanide metal Ln is b, m=ax+by, x is 0<x, y≦2.0, 0.3≦m<4.5, 1.0≦n<2.5 and 1.0≦m/n≦2.0), wherein, in a surface analysis by X-ray photoelectron spectroscopy, a ratio between a peak area of 3d 5/2 spectrum of Eu and a peak area of 2p spectrum of Si, obtained by acid-treating said sialon phosphor particles in which said ratio exceeds 0.5, is 0.5 or less.