Patents by Inventor Syoji Matsuda

Syoji Matsuda 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).

  • Glass substrate for magnetic recording medium, magnetic recording medium, and method of manufacturing the same
    Patent number: 6548139
    Abstract: In a glass substrate for use in a magnetic recording medium, a surface roughness of at least a principal surface of the glass substrate is measured by the use of the interatomic force microscope (AFM), Ra falls within the range between 0.2 and 2.5 nm, Rmax falls within the range between 3 and 25 nm, and Rmax/Ra falls within the range between 3 and 35.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: April 15, 2003
    Assignee: Hoya Corporation
    Inventors: Hiroyuki Sakai, Katsutoshi Ono, Syoji Matsuda
  • Glass substrate for magnetic recording medium, magnetic recording medium, and method of manufacturing the same
    Publication number: 20020142191
    Abstract: In a glass substrate for use in a magnetic recording medium, a surface roughness of at least a principal surface of the glass substrate is measured by the use of the interatomic force microscope (AFM), Ra falls within the range between 0.2 and 2.5 nm, Rmax falls within the range between 3 and 25 nm, and Rmax/Ra falls within the range between 3 and 35.
    Type: Application
    Filed: February 14, 2002
    Publication date: October 3, 2002
    Applicant: HOYA CORPORATION
    Inventors: Hiroyuki Sakai, Katsutoshi Ono, Syoji Matsuda
  • Glass substrate for magnetic recording medium, magnetic recording medium, and method of manufacturing the same
    Patent number: 6383404
    Abstract: In a glass substrate for use in a magnetic recording medium, a surface roughness of at least a principal surface of the glass substrate is measured by the use of the interatomic force microscope (AFM), Ra falls within the range between 0.2 and 2.5 nm, Rmax falls within the range between 3 and 25 nm, and Rmax/Ra falls within the range between 3 and 35.
    Type: Grant
    Filed: August 19, 1999
    Date of Patent: May 7, 2002
    Assignee: Hoya Corporation
    Inventors: Hiroyuki Sakai, Katsutoshi Ono, Syoji Matsuda