PRODUCTION OF RARE EARTH OXIDE FLUORESCENT MATERIAL AND RARE EARTH OXYSULFIDE FLUORESCENT MATERIAL

摘要

PROBLEM TO BE SOLVED: To obtain a rare earth oxide fluorescent material having a sharp particle size distribution and high luminance and useful for fluorescent lamp, etc., by thermally decomposing a specific rare earth element compound to obtain an intermediate composed of a mixed crystal of rare earth oxides having a specific crystal size, adding a flux to the intermediate and baking the mixture. ;SOLUTION: The objective compound of formula (Ln_1-xLn'_x)₂O₃ ((x) is 0.001-0.2) is produced by thermally decomposing compounds consisting of a compound of a rare earth element (Ln) selected from Y, Gd, Sc and Lu and a compound of a rare earth element (Ln') selected from Eu, Tb, Sm, Er, Tm, Dy, Ho, Nd and Pr and easily convertible to oxide by heating (e.g. carbonate or nitrate of a rare earth element) to obtain an intermediate raw material for fluorescent material consisting of a mixed crystal of rare earth oxides (Ln₂O₃.Ln'₂O₃) having a crystallite diameter of 80-200Å determined by powder X-ray diffraction analysis, adding 0.0001-0.1mol of a flux such as barium chloride, strontium chloride or calcium chloride to the intermediate raw material and baking the mixture e.g. at 1250-1500°C.;COPYRIGHT: (C)1997,JPO