Patents by Inventor Tetsuji Iwashita

Tetsuji Iwashita 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).

  • Apparatus and method for detecting a defect on a magneto-optical disk
    Patent number: 5568454
    Abstract: A magneto-optical disk inspecting apparatus in which n pairs of a write head and a read head, and an area of the magneto-optical disk to be inspected are divided into n zones, the respective n pairs being assigned to the respective n zones so that the respective read heads read the data written in the magneto-optical disk by the respective write heads, such that characteristics of the magneto-optical disk can be inspected. An inspection is conducted by n pairs of a write head and a read head assigned to n zones of the area of a magneto-optical disk to be inspected, such that the inspection time can be shortened.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: October 22, 1996
    Assignee: Tosoh Corporation
    Inventors: Yasuji Shima, Tetsuji Iwashita
  • Magneto-optical disk inspecting method and apparatus
    Patent number: 5270879
    Abstract: This invention relates to a magneto-optical disk inspecting apparatus in which n pairs of a write head and a read head, and the area of the magneto-optical disk to be inspected is divided in n zones, the respective n pairs being assigned to the respective n zones so that the respective read heads read the data written in the magneto-optical disk by the respective write heads, whereby characteristics of the magneto-optical disk can be inspected. An inspection is conducted by n pairs of a write head and a read head assigned to n zones of the area of the magneto-optical disk to be inspected, whereby the inspection time can be shortened.
    Type: Grant
    Filed: April 16, 1992
    Date of Patent: December 14, 1993
    Assignee: Tosoh Corporation
    Inventors: Yasuji Shima, Tetsuji Iwashita