Patents by Inventor Zenichi Nagashima

Zenichi Nagashima 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).

  • Information recording medium and method for recording and reproducing information to a medium to prevent unauthorized copying
    Patent number: 5886979
    Abstract: An information recording medium wherein the key information is recorded by arrangement of a unit area recorded irreversibly and a unit area not recorded irreversibly to effect the truth judgment of the medium in accordance with the result of whether or not the reproduction of the key information can be effected, the information recording medium where the illegal usage of the medium is adapted to be prevented without inputting the information on to the medium truth judgment into the processing apparatus by provision of the medium firm information, a reproducing method for the same, a truth judging method for the same, and a recording/reproducing apparatus for the same.
    Type: Grant
    Filed: March 14, 1997
    Date of Patent: March 23, 1999
    Assignee: Fujitsu Limitd
    Inventors: Mineo Moribe, Kenichi Utsumi, Zenichi Nagashima, Hiroyuki Kobayashi, Keiichi Murakami