FLUORESCENT MATERIAL, PROCESS FOR PRODUCING THE SAME, AND ILLUMINATOR EMPLOYING THE SAME

摘要

A fluorescent material which comprises a ß-Sialon represented by the general formula Si_6-ZAl_ZO_ZN_8-Z as a base material and europium in solution as a luminescent center, and is a powder which, when examined by the laser diffraction/scattering method, gives a particle diameter distribution in which the cumulative 10% diameter (D₁₀) is 7-20 µm and the cumulative 90% diameter (D₉₀) is 50-90 µm. It is less apt to decrease in luminescent intensity. Also provided is an illuminator employing this fluorescent material. This fluorescent material can be produced by mixing a silicon nitride powder, an aluminum nitride powder, an aluminum compound as an optional ingredient, and an europium compound and keeping the resultant raw-material powder in a nitrogen atmosphere or non-oxidizing atmosphere at 1,850-2,050°C for 9 hours or longer.