Abstract: A phosphor containing O, Al, In, at least one element M selected from a group consisting of Sr, Ca and Ba, and Eu, as an activator, where the M, the Al, the In and the Eu are present in an atomic ratio M:Al:In:Eu of m:2n(1−y):2n(y):a, 0.3<m/n≦2, 0≦y≦0.2, and 1×10−5≦a≦1×10−1, exhibits excellent luminance, afterglow and durability. Also a phosphor containing O, Al, In, B, at least one element M selected from a group consisting of Sr, Ca and Ba, and Eu2+ as an activator, where the M, the Al, the In, the B and the Eu are present in an atomic ratio M:Al:In:B:Eu of m:2n(1−y−z):2n(y−z):2n(z):a, 0.3≦m/n≦2, 0<y≦0.2, 0<z≦0.05, and 1×10−5≦a≦1×10−1 exhibits excellent luminance, afterglow and durability.

Abstract: A long persistent phosphorescence phosphor contains a europium-activated long persistent phosphorescence silicate phosphor of the formula (I),m(Sr.sub.1-a M.sup.1.sub.a)O.multidot.n(Mg.sub.1-b M.sup.2.sub.b)O.multidot.2(Si.sub.1-c Ge.sub.c)O.sub.2 :Eu.sub.x Ln.sub.y (I)containing at least one halogen atom in a specific amount, and an organic fluorescent pigment which is deposited on the surface of the europium-activated long persistent silicate phosphor.

Abstract: A method for preparing a sulfide phosphor where a raw material mixture for a sulfide phosphor is placed in an almost closed first heat-resistant container and fired therein, the method being characterized in that an auxiliary material composed of carbon and/or a carbon-forming compound capable of being pyrolyzed at a temperature not higher than the firing temperature to form carbon, and a metal sulfide capable of recting with the carbon and/or said carbon-forming compound at a temperature not lower than 600.degree. C. but not higher than the firing temperature to form a carbon sulfide is placed in the portion as physically separated from the raw material mixture for the sulfide phosphor in the said first heat-resistant container and the firing is conducted under such condition so that said first heat-resistant container may have a carbon sulfide atmosphere by the thermal reaction of the thus fired auxiliary materials.