Patents Assigned to Kasei Optonix Limited
  • Patent number: 4874985
    Abstract: A sulfide phosphor emitting green to orange light with long after-glow is represented by the formula of (ZN.sub.1-x,Cd.sub.x)S:eM.sup.I',fM.sup.III', gX' wherein M.sup.I' is at least one of copper and gold, M.sup.III' is at least one of gallium and indium, X' is at least one of chlorine, bromine, iodine, fluorine and aluminum, and x, e, f and g satisfy the conditions of 0.ltoreq.x.ltoreq.0.4, 10.sup.-8 .ltoreq.e.ltoreq.10.sup.-2, 5.times.10 .sup.-8 .ltoreq.f.ltoreq.5.times.10.sup.-3, and 5.times.10.sup.-8 .ltoreq.g.ltoreq.5.times.10.sup.-3. A white emitting phosphor is obtained by mixing the long after-glow yellow emitting phosphor represented by the above formula wherein 0.ltoreq.x.ltoreq.0.3 and 10.sup.-6 .ltoreq.e.ltoreq.10.sup.-2, with a long after-glow blue emitting phosphor. These sulfide phosphors are used to form fluorescent screens of electron excited fluorescent display devices.
    Type: Grant
    Filed: July 25, 1988
    Date of Patent: October 17, 1989
    Assignee: Kasei Optonix Limited
    Inventors: Takashi Hase, Hidemi Yoshida