Method of making small-sized lanthanum

摘要

A phosphor is of formula (LaxCeyTbz)PO4 (x = 0.73-0.37; y = 0.17-0.45; and z = 0.10-0.18) and has an average particle size of below 4 mu m and a brightness at least as great as that of a second phosphor having the same composition and an average particle size of above 4.5 mu m. Also claimed is the method of making the phosphor by combining (LaxCeyTbz)PO4 boric acid and lithium carbonate and firing at 1200[deg]C for 4 hr. in a reducing atmosphere.