Patents by Inventor Yasuhiro Shirakawa

Yasuhiro Shirakawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Charging circuit capable of supplying DC voltage directly to power supply circuit when battery is removed
    Patent number: 5523669
    Abstract: A parallel circuit of a charging resistor and a discharging diode D2 is connected in series only to a battery. An external DC power supply voltage can be supplied from external DC power supply terminals directly to a power supply circuit without going through a charging resistor for the battery.
    Type: Grant
    Filed: July 26, 1993
    Date of Patent: June 4, 1996
    Assignee: NEC Corporation
    Inventors: Setsuya Oku, Yasuhiro Shirakawa
  • Rare earth oxyfluoride barium fluoride halide phosphor
    Patent number: 4515706
    Abstract: A compound having the general formulaaReOF.(1-a)Ba.sub.(1-X) M.sub.x FX:Eu.sub.y,where Re is one element selected from the group consisting of Lu and Y, M is at least one element selected from the group consisting of Be, Mg, Ca, Sr, Zn, and Cd, X is at least one element selected from the group consisting of Cl, Br, and I, a is a positive number less than or equal to 0.6, x is in the range from 0 to 0.5, inclusive, and y is in the range from 10.sup.-6 to 2.times.10.sup.-1, inclusive, is useful as a phosphor, especially in X-ray imaging.
    Type: Grant
    Filed: May 30, 1984
    Date of Patent: May 7, 1985
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Takahara, Tsutomu Ishii, Yasuhiro Shirakawa
  • Method of making picture tube fluorescent screen
    Patent number: 4423128
    Abstract: There are disclosed a composition for making a picture tube fluorescent screen characterized by essentially consisting of a light-sensitive resin at least having recurring units (1) and (2) represented by the formulas: ##STR1## wherein R and X.sup.- have the same meanings as defined in the specification, and CaS-based phosphor particles surface-coated with SiO.sub.2 which are dispersed in an aqueous medium, and a method of making a picture tube fluorescent screen using the same.According to this invention, it is possible to make a picture tube exhibiting an excellent light emitting efficiency and a contrast by a simple process.
    Type: Grant
    Filed: September 20, 1982
    Date of Patent: December 27, 1983
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Norio Koike, Takeshi Takahara, Yasuhiro Shirakawa, Kunihiro Ikari