Patents by Inventor Hiroto Takeshita

Hiroto Takeshita 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: 20040131891
    Abstract: A method of fabricating a magnetic recording medium is disclosed, including a monomolecular film formation step of forming a monomolecular film on a substrate and a magnetic film formation step of forming on the monomolecular film a magnetic film for recording magnetic information. In the monomolecular film formation step, it is preferable to form a perylene-based organic monomolecular film.
    Type: Application
    Filed: November 7, 2003
    Publication date: July 8, 2004
    Applicant: FUJITSU LIMITED
    Inventors: Hiroto Takeshita, Takuya Uzumaki
  • Patent number: 6677023
    Abstract: A non-magnetic substrate for a magnetic recording medium is formed or molded within a die. The die is designed to define embedment depressions on the surface of the resulting non-magnetic substrate. Any bumps or lugs formed on the inner surface of the die can be employed to form the embedment depressions on the non-magnetic substrate. A magnetic material fills the individual embedment depression so as to establish a magnetic block embedded into the surface of the non-magnetic substrate. The magnetic block can be utilized as a positional mark in a tracking servo control for a corresponding read/write head in a magnetic storage system.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: January 13, 2004
    Assignee: Fujitsu Limited
    Inventors: Hiroto Takeshita, Hitoshi Komoriya
  • Publication number: 20030228499
    Abstract: The present invention provides a perpendicular magnetic recording medium that reduces medium noise and achieves thermal stability of recording magnetization. This perpendicular magnetic recording medium has a substrate and a recording layer formed by single-layered magnetic nanoparticles that are aligned at uniform intervals. An auxiliary magnetic film that is thinner than the recording layer is interposed between the substrate and the recording layer. The magnetization of the magnetic nanoparticles is secured by the exchange interaction effect of the auxiliary magnetic film.
    Type: Application
    Filed: January 17, 2003
    Publication date: December 11, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Maki Maeda, Hiroto Takeshita, Takuya Uzumaki
  • Patent number: 6586044
    Abstract: A magnetic hard disk having magnetic tracks for storing data which is read or written by a magnetic head floating immediately above the magnetic track while the magnetic hard disk is rotating, and the magnetic head rests on the magnetic hard disk while the magnetic hard disk is not rotating. One aspect of the present invention is that the magnetic hard disk comprises a non-magnetic substrate having a plurality of banks and grooves alternately and concentrically arranged thereon, a magnetic film formed on each of the banks, and non-magnetic material formed on an entire surface of the substrate all over the banks and grooves such that roughness of the upper surface of the non-magnetic material is in a range between 0.5 nm and 3 nm.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: July 1, 2003
    Assignee: Fujitsu Limited
    Inventors: Hiroto Takeshita, Ryoichi Mukai, Wataru Yamagishi
  • Patent number: 6583957
    Abstract: A magnetic hard disk has magnetic tracks for storing data, which is read or written by a magnetic head floating immediately above the magnetic track while the magnetic hard disk is rotating. The magnetic head rests on the magnetic hard disk while the magnetic hard disk is not rotating. The magnetic hard disk comprises a non-magnetic substrate having a plurality of banks and grooves alternately and concentrically arranged thereon, a magnetic film formed on each of the banks, and a non-magnetic material formed on an entire surface of the substrate all over the banks and grooves such that roughness of the upper surface of the non-magnetic material is in a range between 0.5 nm and 3 nm.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: June 24, 2003
    Assignee: Fujitsu Limited
    Inventors: Hiroto Takeshita, Ryoichi Mukai, Wataru Yamagishi
  • Publication number: 20030112560
    Abstract: A magnetic hard disk having magnetic tracks for storing data which is read or written by a magnetic head floating immediately above the magnetic track while the magnetic hard disk is rotating, and the magnetic head rests on the magnetic hard disk while the magnetic hard disk is not rotating. One aspect of the present invention is that the magnetic hard disk comprises a non-magnetic substrate having a plurality of banks and grooves alternately and concentrically arranged thereon, a magnetic film formed on each of the banks, and non-magnetic material formed on an entire surface of the substrate all over the banks and grooves such that roughness of the upper surface of the non-magnetic material is in a range between 0.5 nm and 3 nm.
    Type: Application
    Filed: September 27, 2002
    Publication date: June 19, 2003
    Applicant: Fujitsu Limited
    Inventors: Hiroto Takeshita, Ryoichi Mukai, Wataru Yamagishi
  • Publication number: 20020150793
    Abstract: A magnetic recording medium is provided. The magnetic recording medium comprises an in-plane magnetic film used for recording, and a perpendicular magnetic film formed on the in-plane magnetic film. The in-plane magnetic film has a magnetization easy axis in an in-plane direction. The perpendicular magnetic film has a magnetization easy axis oriented in a direction perpendicular to the magnetization easy axis of the in-plane magnetic film. A tBr (a product of a thickness and a residual magnetization) of the perpendicular magnetic film is set so as not to exceed one-fifth of a tBr of the in-plane magnetic film at the maximum.
    Type: Application
    Filed: October 12, 2001
    Publication date: October 17, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Maki Maeda, Hiroto Takeshita, Takuya Uzumaki, Atsushi Tanaka
  • Publication number: 20020055018
    Abstract: The surface of a disk medium includes a substrate whose surface includes grooves and lands. A non-magnetic underlayer and a magnetic recording layer are formed on the substrate. Smoothing non-magnetic film fills the grooves, which are covered with the non-magnetic underlayer and the magnetic recording layer, so that the height of the magnetic recording layer above the grooves may reach the same level as the height of the magnetic recording layer above the lands.
    Type: Application
    Filed: November 21, 2001
    Publication date: May 9, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Hiroto Takeshita, Wataru Yamagishi
  • Publication number: 20020022147
    Abstract: A non-magnetic substrate for a magnetic recording medium is formed or molded within a die. The die is designed to define embedment depressions on the surface of the resulting non-magnetic substrate. Any bumps or lugs formed on the inner surface of the die can be employed to form the embedment depressions on the non-magnetic substrate. A magnetic material fills the individual embedment depression so as to establish a magnetic block embedded into the surface of the non-magnetic substrate. The magnetic block can be utilized as a positional mark in a tracking servo control for a corresponding read/write head in a magnetic storage system.
    Type: Application
    Filed: March 20, 2001
    Publication date: February 21, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Hiroto Takeshita, Hitoshi Komoriya
  • Patent number: 6277484
    Abstract: A magnetic recording medium using a substrate, such as a glass substrate, and having, in combination, superior magnetic and magnetic recording properties and good adhesion of a magnetic layer to the substrate. The magnetic recording medium has an intermediate layer of chromium between the substrate and an underlayer of Ni-based non-magnetic material on which a magnetic layer of Co-based magnetic alloy is superimposed. A method of producing the magnetic recording medium is also disclosed, wherein each of the layers is formed by a sputtering process at a sufficient pressure to promote granular growth of crystals of the layer.
    Type: Grant
    Filed: October 7, 1998
    Date of Patent: August 21, 2001
    Assignee: Fujitsu Limited
    Inventors: Kazumasa Shimoda, Ryoichi Mukai, Hiroto Takeshita
  • Publication number: 20010010603
    Abstract: Disclosed is a data refresh method for preventing the disappearance of data on a storage medium, and for detecting refresh target data accurately and in a short time. A storage system has a storage medium 6, a head 4, and a control unit 30 for carrying out refresh processing. A refresh operation extracts data that needs to be refreshed by measuring the read-out output level of target data. Then, data requiring the refresh is re-recorded to the storage medium 6 by the head 4. Because an actual data level is observed, it is possible to accurately detect refresh target data, and because there is no need for a reference area, it is possible to prevent a reduction in storage capacity.
    Type: Application
    Filed: January 26, 2001
    Publication date: August 2, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Takuya Uzumaki, Kazumasa Shimoda, Hiroto Takeshita, Atsushi Tanaka