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

摘要

A fluorescent material comprising: a ²-Sialon expressed by the general formula Si 6-z Al z O z N 8-z as a host material; and Eu dissolved in solid solution as a luminescence center, is a powder which, when measured by the laser diffraction scattering method, gives particle diameter distribution in which cumulative 10% diameter (D 10 ) falls within the 7 µm to 20 µm range and 90% diameter (D 90 ) within the 50 µm to 90 µm range, and can be used as a fluorescent material low in luminescence intensity degradation ideal for illuminators. This fluorescent material can be produced by subjecting a raw powder, which is obtained by mixing a silicon nitride powder, aluminum nitride powder, and aluminum-containing or Eu-containing compound as required, to heating at 1850°C to 2050°C for 9 hours or longer in a nitrogen or nonoxidizing atmosphere.