Patents by Inventor Masataka Yokoyama

Masataka Yokoyama 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).

  • Patent number: 5899794
    Abstract: A method for polishing or texturing a magnetic disc, comprises bringing a tape traveled in a predetermined direction and made of fibers having a fineness of not more than 0.1 denier, and a slurry containing polishing grains dispersed therein, into contact with a substrate of the magnetic disc. Such method has an extremely low surface roughness (Ra) and an extremely low maximum projection height (Rp) with an excellent high accuracy, thereby efficiently producing a magnetic recording medium which is free from head crash and errors upon reading and writing of information.
    Type: Grant
    Filed: December 23, 1997
    Date of Patent: May 4, 1999
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Tomoo Shige, Masataka Yokoyama, Makabe Yasushi
  • Patent number: 5437779
    Abstract: A method of making a-magnetic record medium comprising the steps of: texturing a surface of a substrate by a first surface treatment; electrolyzing the surface of the textured substrate in an electrolyte of an acidic solution by applying an electric potential on the nonmagnetic substrate by a second surface treatment; and forming an undercoating layer and a magnetic layer on the surface of the electrolyzed substrate.
    Type: Grant
    Filed: December 9, 1993
    Date of Patent: August 1, 1995
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Tomoo Shige, Yasushi Makabe, Masataka Yokoyama