Patents by Inventor Hiroki Matsukuma

Hiroki Matsukuma 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).

  • Publication number: 20050270694
    Abstract: A thin-film magnetic head according to the present invention comprises: a substrate; at least one magnetic head element formed on the substrate; an overcoat multilayer composed of a plurality of overcoat layers, formed on the substrate so as to cover the at least one magnetic head element; and at least one heating element to be heated at least during operation of the at least one magnetic head element, the at least one heating element provided in the overcoat multilayer, and a coefficient of thermal expansion of an overcoat layer located farthest from the substrate in the overcoat multilayer being smaller than a coefficient of thermal expansion of an overcoat layer located closest to the substrate in the overcoat multilayer.
    Type: Application
    Filed: May 13, 2005
    Publication date: December 8, 2005
    Applicant: TDK Corporation
    Inventors: Tsuyoshi Umehara, Norikazu Ota, Katsumichi Tagami, Hiroki Matsukuma, Nobuya Oyama, Soji Koide, Yoshiyuki Mizoguchi, Kazuhide Yamada
  • Publication number: 20050195513
    Abstract: The invention is directed to a magnetic head driving circuit and a magnetic disk device which achieve a low flying-height with thermal protrusion and thus a reliable write operation on the magnetic disk. The write circuit 3 receives the write data signal Sw inputted therein, and generates and outputs the write voltages Wx, Wy based upon the inputted signal. The write voltages Wx, Wy are composed of a preamble portion T1, a sink mark T2 and a user data portion T3 in each sector for magnetic recording. In the write voltage, the frequency f2 of the signal in the preamble portion T1 is higher than half the frequency f1 of the signal in the user data portion T3.
    Type: Application
    Filed: March 2, 2005
    Publication date: September 8, 2005
    Inventors: Mitsuo Otsuki, Hiroshi Kiyono, Nobutaka Nishio, Hiroki Matsukuma
  • Publication number: 20050095956
    Abstract: The present invention relate to provide a lapping method and apparatus that increases the yield rate in the magnetic head slider manufacturing process, but does not make output and asymmetry characteristics worse. According to the invention, an apparatus for lapping thin film magnetic heads includes a jig block and a lapping plate. The jig block includes a first jig that holds a bar to be lapped, and second jig that holds a member for load sharing. The lapping plate is movable relative to the first jig and the second jig, and is contactable with the surface to be lapped of the bar held by the first jig and the member for load sharing held by the second jig for lapping.
    Type: Application
    Filed: September 13, 2004
    Publication date: May 5, 2005
    Applicants: SAE Magnetics (H.K.) Ltd., TDK CORPORATION
    Inventors: Ryuji Fujii, Hiroki Matsukuma
  • Publication number: 20050078413
    Abstract: An HGA includes a magnetic head slider provided with at least one thin-film magnetic head element, and a conductive suspension to which the magnetic head slider is fixed. A conductive resistance between the magnetic head slider and the suspension is equal to or higher than 1 M?.
    Type: Application
    Filed: September 2, 2004
    Publication date: April 14, 2005
    Applicants: SAE Magnetics (H.K) Ltd., TDK CORPORATION
    Inventors: Tatsushi Shimizu, Pak Wong, Hiroki Matsukuma, Masaru Hirose
  • Publication number: 20050073300
    Abstract: In the method of inspecting a thin-film magnetic head, a thin-film magnetic head provided with a magnetoresistive film having a free layer whose magnetization direction changes depending on an external magnetic field and ferromagnetic layers for applying a bias magnetic field to the free layer is prepared. Then, a DC magnetic field is applied to the ferromagnetic layers in the bias magnetic field applying direction. Subsequently, an AC magnetic field is applied to the ferromagnetic layers in the bias magnetic field applying direction. Thereafter, an external magnetic field is applied to the magnetoresistive film while supplying a current thereto, and a property of the thin-film magnetic head such as asymmetry and reproducing output is inspected.
    Type: Application
    Filed: August 17, 2004
    Publication date: April 7, 2005
    Applicants: TDK CORPORATION, SAE MAGNETICS (H.K.) LTD.
    Inventors: Hiroki Matsukuma, Muneyoshi Kobashi