Patents by Inventor Shinji Tokuhara

Shinji Tokuhara 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).

  • Large-capacity-memory disk
    Patent number: 5080945
    Abstract: In a large capacity memory disk of the type in which data are read out by an optical system, the invention provides a large capacity memory disk characterized in that a methyl methacrylate copolymer consisting of 99 to 20 percent by weight methyl methacrylate and 1 to 80 percent by weight of a monomer copolymerizable with methyl methacrylate is used as the disk substrate.
    Type: Grant
    Filed: February 19, 1991
    Date of Patent: January 14, 1992
    Assignee: Daicel Chemical Industries, Ltd.
    Inventors: Takeshi Moriwaki, Shinji Tokuhara
  • Large diameter optical disk substrate made of polycarbonate
    Patent number: 4764331
    Abstract: A disk substrate for a high-density information recording medium made by injection molding from polycarbonate is disclosed having an average molecular weight from 14,000 to 22,000 and having a thickness from 1.0 to 2.0 mm and a circular recording area of between two concentric circles having a radii of 40 to 170 mm, respectively. The birefringence of the substrate within the recording area is less than 25 mm and is uniformly distributed.
    Type: Grant
    Filed: April 27, 1987
    Date of Patent: August 16, 1988
    Assignee: Daicel Chemical Industries, Ltd.
    Inventors: Shinji Tokuhara, Yoshio Onizawa, Shuzo Iyoshi
  • Moldable resin compositions containing polycarbonate styrene polymer and three phase graft polymer
    Patent number: 4393169
    Abstract: A moldable resin composition comprising:(A) an aromatic vinyl-type polymer;(B) a polycarbonate; and(C) a three-stage polymerization product produced by three-stage emulsion polymerizations of an aromatic vinyl-type monomer, butadiene, alkyl methacrylate, etc.
    Type: Grant
    Filed: November 12, 1981
    Date of Patent: July 12, 1983
    Assignee: Daicel Chemical Industries, Ltd.
    Inventors: Takeshi Moriwaki, Shinji Tokuhara