Patents by Inventor Kiyotsune Yoshimatsu

Kiyotsune Yoshimatsu 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).

  • Method of quality-testing a shield film of a magnetoresistive effect head
    Patent number: 7414394
    Abstract: When testing the quality of shield films of magnetoresistive effect heads, a method of testing and a testing apparatus can detect heads where the shield magnetic domain is susceptible to changing that could not be completely detected by conventional methods of testing that use normal magnetization. The method of testing applies an external magnetic field to a magnetoresistive effect head as external stress, measures the output voltage of the head, and repeats the applying of the external magnetic field and the measuring a plurality of times to test the quality of the shield film. The magnetic field is applied in a direction parallel to the shield film and at an angle to a floating surface of the magnetoresistive effect head. The intensity of the applied magnetic field is smaller than the coercive force of a hard bias film and larger than the coercive force of the shield film.
    Type: Grant
    Filed: September 6, 2006
    Date of Patent: August 19, 2008
    Assignee: Fujitsu Limited
    Inventors: Masahiro Yasunaga, Takuji Furutani, Hiroshi Maeda, Minoru Sawada, Kiyotsune Yoshimatsu
  • Method of testing and testing apparatus for a magnetoresistive effect head
    Publication number: 20070273370
    Abstract: When testing the quality of shield films of magnetoresistive effect heads, a method of testing and a testing apparatus can detect heads where the shield magnetic domain is susceptible to changing that could not be completely detected by conventional methods of testing that use normal magnetization. The method of testing applies an external magnetic field to a magnetoresistive effect head as external stress, measures the output voltage of the head, and repeats the applying of the external magnetic field and the measuring a plurality of times to test the quality of the shield film. The magnetic field is applied in a direction parallel to the shield film and at an angle to a floating surface of the magnetoresistive effect head. The intensity of the applied magnetic field is smaller than the coercive force of a hard bias film and larger than the coercive force of the shield film.
    Type: Application
    Filed: September 6, 2006
    Publication date: November 29, 2007
    Applicant: FUJITSU LIMITED
    Inventors: Masahiro Yasunaga, Takuji Furutani, Hiroshi Maeda, Minoru Sawada, Kiyotsune Yoshimatsu