The Ln ion (Ln +3 ) of the tonnage which satisfies the above-mentioned composition formula stoichiometrically production manner of the rare earth

摘要

PROBLEM TO BE SOLVED: To obtain a rear earth phosphate and a rare earth phosphate fluorescent substance scarcely causing the deterioration of the initial luminance, deterioration of luminance maintenance factor when continuously lit and temperature quenching and readily controlling the particle diameter and to provide a method for producing the same.;SOLUTION: This rare earth phosphate is characterized in that the rare earth phosphate is represented by the compositional formula LnxCeyTbzPO4 [wherein Ln denotes one or more kinds of elements selected from the group of La, Gd and Y; x, y and z denote each a number satisfying 0≤x1; 0≤y≤1; 0≤z≤0.4 and (x+y+z)=1] and the powder reflectance at 490 nm wavelength after calcining at 120-900°C temperature in air is ≥99% based on the reflectance of MgO powder. The method for producing the same is obtained. The fluorescent substance uses the rear earth phosphate and the method for producing the same is obtained.;COPYRIGHT: (C)2001,JPO