Dai Nippon Toryo Co., Ltd.

Kasei Optonix, Ltd.

Isao Iwamoto

Noboru Kotera

Shusaku Eguchi

Kazuhito Iwasaki

Katuzo Kanda

Thihiro Yoshida

Seiji Murakami

Toshiaki Hatsumi

Pigment coated phosphors comprising a europium activated yttrium oxysulfide phosphor having a europium activator value within a range of 0.04 gram atom to 0.066 gram atom per 1 mol of yttrium oxysulfide having adhered thereto red colored pigment particles such as cadmium sulfoselenide pigment particles, rouge pigment particles or red lead pigment particles, in respective amounts of 0.1 to 2.0 wt %, 0.05 to 2.0 wt % or 0.1 to 12 wt %, based upon the europium activated yttrium oxysulfide phosphor; and a cathode ray tube for high contrast color television using as a red emitting phosphor at least one of the three pigment coated phosphors.

Pigment coated phosphor and high contrast color television cathode ray

On the surface of a phosphor, pigment particles are uniformly adhered by a layer of a gelatin-gum arabic mixture. A process for manufacturing such a pigment coated phosphor includes the steps of preparing an aqueous solution of gelatin and an aqueous solution of gum arabic, allowing the phosphor to disperse homogeneously into one of these aqueous solutions, allowing the pigment particles to disperse homogeneously into the other aqueous solution, and mixing the so obtained phosphor and pigment dispersions.

Pigment coated phosphor and process for manufacturing the same

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Hiratsuka, Japan

Isao Iwamoto