ULTRAVIOLET-LUMINESCENT MATERIAL, AND ULTRAVIOLET- LUMINESCENT FLUORESCENT-LAMP AND ULTRAVIOLET- LUMINESCENT ELEMENT USING SAME

摘要

PROBLEM TO BE SOLVED: To provide a novel ultraviolet-luminescent material, and an ultraviolet- luminescent fluorescent-lamp and an ultraviolet-luminescent element which show improved near ultraviolet light strengths by incoporating therein the material and are suitable as photocatalysts. SOLUTION: The novel ultraviolet-luminescent material contains luminescence-related rare earth element(s) comprising at least gadolinium or gadolinium and praseodymium in the mother crystals. A phosphor layer 2 comprising a rare-earth-activated yttrium fluoride (YF3: Gd, Pr) phosphor that emits light by vaccuum ultraviolet radiation excitation is formed on the inner wall of a light-transmittant hermetic vessel composed of a soda glass tube 1, and electrodes 5 and 6 and gaseous xenon are encapsulated in the glass tube 1. A photocatalyst layer 7 comprising anatase-type TiO2 is formed on the outer surface of the glass tube 1. When electrical discharge is caused by applying a high-frequency voltage to the cold anodes 5 and 6 to irradiate vacuum ultraviolet rays of 172 nm from the xenon, the phosphor layer 2 irradiates near ultraviolet rays efficiently. The photocatalyst layer 7 shows a photocatalytic action by the near ultraviolet rays.