Patents by Inventor Isatake Kaitsu

Isatake Kaitsu 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).

  • Patent number: 6713196
    Abstract: The present invention provides a high-density, low-noise magnetic recording medium. This magnetic recording medium includes a substrate, a non-magnetic underlayer formed on the substrate, and a magnetic recording layer formed on the underlayer. The magnetic recording layer contains cobalt as the main component, 10 atm % to 18 atm % of chromium, 5 atm % to 20 atm % of platinum, and 10 atm % to 20 atm % of boron.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: March 30, 2004
    Assignee: Fujitsu Limited
    Inventor: Isatake Kaitsu
  • Patent number: 6689495
    Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer. At least one of the ferromagnetic layer and the magnetic layer has a granular layer structure in which ferromagnetic crystal grains are uniformly distributed within a non-magnetic base material.
    Type: Grant
    Filed: June 6, 2000
    Date of Patent: February 10, 2004
    Assignee: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita
  • Patent number: 6562481
    Abstract: A magnetic storage medium has a non-magnetic substrate and a recording layer. The recording layer comprises a non-magnetic matrix and crystal grains consisting of a ferromagnetic material. Each of the crystal grains dispersed in the recording layer is a columnar shaped grain which penetrates a suface of the recording layer and has height of 30 nm or less, and a mean value of grain sizes of the crystal grains in an internal direction of the recording layer is 15 nm or less. (Ku·V)/(kB·T) is not less than 60. A mean value Hk of anisotropic magnetic fields of the plurality of crystal grains is 20 kOe or less.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: May 13, 2003
    Assignee: Fujitsu Limited
    Inventors: Isatake Kaitsu, Hisateru Sato, Iwao Okamoto
  • Publication number: 20030082410
    Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer. At least one of the ferromagnetic layer and the magnetic layer has a granular layer structure in which ferromagnetic crystal grains are uniformly distributed within a non-magnetic base material.
    Type: Application
    Filed: December 2, 2002
    Publication date: May 1, 2003
    Applicant: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita
  • Patent number: 6534205
    Abstract: There is provided a magnetic storage medium capable of recording information at high recording density and also to regenerating the information with a high quality of signal (high S/Nm), and in addition contributing to the elongation of a life span of the recorded information. The magnetic storage medium comprises a non-magnetic substrate and a magnetic recording layer provided on the substrate. The magnetic recording layer has a ferromagnetic grain consisting of a ferromagnetic material and an antiferromagnetic matrix consisting of an antiferromagnetic material.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: March 18, 2003
    Assignee: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, Iwao Okamoto
  • Publication number: 20020064685
    Abstract: There is provided a magnetic storage medium capable of recording information at high recording density and also to regenerating the information with a high quality of signal (high S/Nm), and in addition contributing to the elongation of a life span of the recorded information. The magnetic storage medium comprises a non-magnetic substrate and a magnetic recording layer provided on the substrate. The magnetic recording layer has a ferromagnetic grain consisting of a ferromagnetic material and an antiferromagnetic matrix consisting of an antiferromagnetic material.
    Type: Application
    Filed: September 30, 1999
    Publication date: May 30, 2002
    Inventors: HISATERU SATO, ISATAKE KAITSU, IWAO OKAMOTO
  • Publication number: 20010012573
    Abstract: A magnetic recording medium is provided which has ferromagnetic crystal grains having a uniform grain size which are successfully separated from each other. The magnetic recording medium comprises a non-magnetic substrate 1 and a recording layer 2 formed thereon, wherein the recording layer consists of at least one non-ferromagnetic material selected from the group consisting of non-magnetic materials and antiferromagnetic materials and a plurality of crystal grains 2—1 made of ferromagnetic material solid-insoluble with the non-ferromagnetic material which are dispersed in the non-ferromagnetic material. The recording layer has at least two phases, along the depth direction, with each phase having a different mean composition ratio of the ferromagnetic material to the non-ferromagnetic material from that or those of the adjacent phase or phases.
    Type: Application
    Filed: December 8, 2000
    Publication date: August 9, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Isatake Kaitsu, Hisateru Sato, Iwao Okamoto
  • Patent number: 5843569
    Abstract: A magnetic recording medium comprising: a substrate; and a magnetic recording layer provided on the substrate, the magnetic recording layer being comprised of a thin film of a nonmagnetic material with crystal grains of Co.sub.100-x Pt.sub.x, wherein 10.ltoreq..times.<20, having an f.c.c. structure and an average grain diameter of not more than 50 nm being substantially uniformly dispersed therein, the product of the residual magnetization and the thickness of the magnetic recording layer being not more than 150 Gauss..mu.m.
    Type: Grant
    Filed: February 24, 1997
    Date of Patent: December 1, 1998
    Assignee: Fujitsu Limited
    Inventors: Isatake Kaitsu, Iwao Okamoto
  • Patent number: 5774783
    Abstract: The present invention relates to a magnetic recording medium for use in an external memory device of an information processing apparatus etc., and an object thereof is to reduce noise, achieve high coercive force, and use the substance as a magnetic recording medium for detecting signals in a magnetoresistance head. In the magnetic recording medium comprising the magnetic recording layer 25 including ferromagnetic grains 22 and a nonmagnetic substance 23, the improvement in structure comprises that the ferromagnetic grains 22 are formed to have respectively an average grain diameter of 50 nm or less and not to be overlapped in the film thickness direction and to be isolated in the direction along a layer surface, and that a product of residual magnetization and a film thickness of the magnetic recording layer 25 is less than or equal to 150 Gauss.cndot..mu.m.
    Type: Grant
    Filed: January 31, 1996
    Date of Patent: June 30, 1998
    Assignee: Fujitsu Limited
    Inventors: Isatake Kaitsu, Iwao Okamoto, Masayoshi Shinohara
  • Patent number: 5523639
    Abstract: An electrostatic actuator includes a supporting body having a plurality of electrodes are formed at predetermined intervals, and a movable body having a ferroelectrics layer having an area on which polarization charges based on residual dielectric polarization are distributed in a predetermined polarity pattern so as to correspond to the plurality of electrodes of the supporting body. Due to changing, based on switching a pattern of polarities of voltages supplied to the plurality of electrodes, electrostatic attraction and repulsion between the plurality of electrodes of the supporting body and the area of the ferroelectrics layer on which the polarization charges are distributed, the movable body are moved on the supporting body.
    Type: Grant
    Filed: August 2, 1994
    Date of Patent: June 4, 1996
    Assignee: Fujitsu Limited
    Inventors: Iwao Okamoto, Isatake Kaitsu, Minoru Takahashi
  • Patent number: RE38587
    Abstract: The present invention relates to a magnetic recording medium for use in an external memory device of an information processing apparatus etc., and an object thereof is to reduce noise, achieve high coercive force, and use the substance as a magnetic recording medium for detecting signals in a magnetoresistance head. In the magnetic recording medium comprising the magnetic recording layer 25 including ferromagnetic grains 22 and a nonmagnetic substance 23, the improvement in structure comprises that the ferromagnetic grains 22 are formed to have respectively an average grain diameter of 50 nm or less and not to be overlapped in the film thickness direction and to be isolated in the direction along a layer surface, and that a product of residual magnetization and a film thickness of the magnetic recording layer 25 is less than or equal to 150 Gauss•&mgr;m.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: September 14, 2004
    Assignee: Fujitsu Limited
    Inventors: Isatake Kaitsu, Iwao Okamoto, Masayoshi Shinohara