Tokyo Shibaura Denki Kabushiki Kaisha

Tokyo Shibaura Electric Co., Ltd.

Mitsuhiro Oikawa

Minoru Watanabe

Masao Asada

Toshio Nishimura

Masao Tezuka

Susumu Matsuura

Tsurahide Cho

Disclosed is a method for surface treatment of phosphor particles which comprises forming a continuous film of silicon dioxide on the surface of each phosphor particle by treating the phosphor particle with a solution containing an aqueous solution of organic alkali and silicon dioxide dissolved therein.

Method for surface treatment of phosphor particles

A zinc sulfide phosphor having no segregated free sulfides of copper and gold on the surface layer thereof, which contains 0.003 to 0.03% by weight of copper and 0.01 to 0.2% by weight of gold as co-activators and further 0.0025 to 0.04% by weight of aluminum each on the basis of the zinc sulfide. The chromaticity of the emission from the phosphor is in the range of x=0.310 to 0.350 and y=0.560 to 0.600 on CIE chromaticity coordinates. A method for the preparation of this zinc sulfide phosphor which comprises adding aluminum fluoride as the aluminum ion source and ammonium iodide as the flux compound to powdery raw material for phosphor composed of zinc sulfide and the activator compounds, and firing the formed mixture in a reducing sulfurous atmosphere, thereby removing any segregated free sulfides of copper and gold.

Method of preparing zinc sulfide phosphor coactivated with copper and

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Kawasaki, Japan

Mitsuhiro Oikawa