Patents Assigned to Hokuto Electronics Co., Ltd.
  • Patent number: 4804882
    Abstract: A cathode-ray tube according to the present invention is provided with a phosphor screen comprising phosphors A, B, and C, wherein each of the phosphors A and B constitute 5 to 15% by weight and, the phosphor C constitutes 70 to 90% by weight. The phosphor A is a bluish white-emitting phosphor (Y.sub.1-x-y Gd.sub.x Tb.sub.y).sub.2 O.sub.2 S (0.ltoreq.X.ltoreq.0.999999 and 0.000001.ltoreq.Y.ltoreq.0.001), the phosphor B is at least one of a blue-emitting silver-activated hexagonal zinc sulfate (ZnS:Ag) phosphor, etc., and the phosphors C is a yellow-emitting phosphor (In.sub.1-p-r M.sub.p TB.sub.q Eu.sub.r BO.sub.3) (wherein M is at least one element selected from the group consisting of Sc, Lu, Y, Gd, and Ga, and p, q, and r satisfy 0.ltoreq.p.ltoreq.0.2, 0.0005.ltoreq.q.ltoreq.0.05, and 0.001.ltoreq.r.ltoreq.0.1). The cathode-ray tube of the present invention is a phosphor screen which is free from toxicity and has good flickering and brightness characteristics and high current dependence of brightness.
    Type: Grant
    Filed: July 2, 1987
    Date of Patent: February 14, 1989
    Assignees: Kabushiki Kaisha Toshiba, Hokuto Electronics Co., Ltd.
    Inventors: Takeshi Takahara, Mitsuhiro Oikawa, Yoshinori Tetsuishi, Kazuaki Higuchi, Masaaki Tamatani