Patents by Inventor Shigekazu Ohtomo

Shigekazu Ohtomo 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: 7821737
    Abstract: Embodiments of the invention provide a thin film magnetic head suitable for high density recording having a small erase band ?E and a small fringe magnetic field, and a large recording magnetic field. In one embodiment, a width LW of a lower magnetic pole piece protuberance of a leading side magnetic pole piece, at a face in contact with a write gap layer, is made smaller than a width TW of an upper magnetic pole piece front layer of a trailing side magnetic pole piece, at a face in contact with the write gap layer, and the width of the lower magnetic pole piece protuberance adjacent to the write gap layer is made larger, in a direction from the write gap layer.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: October 26, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Shigekazu Ohtomo, Hiroshi Fukui, Toshimi Yokoyama
  • Patent number: 7576952
    Abstract: In one embodiment, a thin-film magnetic head with a write head has a lower core member made of a soft magnetic film, a planar upper core member made of a soft magnetic film, and a coil conductor positioned between the lower and upper core members. The rear end is equipped with a magnetic body, which at least magnetically joins the lower and upper core members. A magnetic pole piece is in contact with the lower core member and positioned toward an air bearing surface, which faces a recording medium. A first nonmagnetic film is provided between a pedestal magnetic pole piece and upper core member. The write head is structured so that the first nonmagnetic film constitutes a write gap. A second nonmagnetic film is provided above or below the first nonmagnetic film. The edge of the second nonmagnetic film is retracted from the air bearing surface. The upper core member's flare point is positioned toward the air bearing surface rather than the edge of the second nonmagnetic film.
    Type: Grant
    Filed: September 30, 2004
    Date of Patent: August 18, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Yoji Maruyama, Tadayuki Iwakura, Makoto Morijiri, Shigekazu Ohtomo, Ichiro Ohdake
  • Patent number: 7310203
    Abstract: There is provided a thin film magnetic head, with letting a distance of a portion, where a width of a track portion in an upper magnetic pole changes, from a flying plane from a medium be Ly, and letting a distance of a portion, where a distance between right and left of a surface portion in a lower magnetic pole in a track width direction is wider than the width of the upper magnetic pole in the track width direction, from the flying plane from a medium be Tp, by creating a thin film magnetic head that is equipped with a recording head that has a relation of Tp?Ly, it becomes possible to reduce a needless leakage magnetic field in the track width direction with securing magnetic field strength.
    Type: Grant
    Filed: September 10, 2002
    Date of Patent: December 18, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Nobuo Yoshida, Ichiro Oodake, Moriaki Fuyama, Kazue Kudo, Kimitoshi Etoh, Shigekazu Ohtomo, Hiroshi Fukui
  • Publication number: 20070019326
    Abstract: Embodiments of the invention provide a thin film magnetic head suitable for high density recording having a small erase band ?E and a small fringe magnetic field, and a large recording magnetic field. In one embodiment,a width LW of a lower magnetic pole piece protuberance of a leading side magnetic pole piece, at a face in contact with a write gap layer, is made smaller than a width TW of an upper magnetic pole piece front layer of a trailing side magnetic pole piece, at a face in contact with the write gap layer, and the width of the lower magnetic pole piece protuberance adjacent to the write gap layer is made larger, in a direction from the write gap layer.
    Type: Application
    Filed: July 14, 2006
    Publication date: January 25, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Shigekazu Ohtomo, Hiroshi Fukui, Toshimi Yokoyama
  • Patent number: 7142392
    Abstract: A thin film head having reading part and recording part having an upper magnetic pole front end layer and a lower magnetic pole having a lower magnetic main layer, a lower magnetic pole front end portion on the lower magnetic main layer, and a projection step portion on the lower magnetic pole front end portion. The upper magnetic pole front end layer has a magnetic pole expansion position and a length from an air bearing surface to the magnetic pole expansion position is less than a length from the air bearing surface to gap depth position of the lower magnetic pole front end portion.
    Type: Grant
    Filed: December 3, 2004
    Date of Patent: November 28, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Patent number: 7142391
    Abstract: A lower magnetic pole front end portion is provided on a lower magnetic pole main layer, and then, an upper magnetic pole front end portion or an upper magnetic pole front end layer is formed on the flat surface so as to enhance the track width accuracy of thin film head. The height of the lower magnetic pole front end portion is increased so as to enhance the magnetic field intensity. A projection step portion having a width larger than that of the upper magnetic pole front end layer is provided on the lower magnetic pole front end portion. The unnecessary medium in-plane magnetic field can be thus reduced in the off-track position. The respective parts of the head are corrected, thereby realizing a high recording magnetic field intensity exceeding 716 kA/m (9000Oe).
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: November 28, 2006
    Assignee: Hitachi Global Storage Tehcnologies Japan, Ltd.
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Patent number: 7061726
    Abstract: A magnetic material having a low coefficient of thermal expansion of 11.5×10?6/K or less is used for forming at least one of a lower shield or an upper shield. A laminated film comprising a layer of the magnetic material having a low coefficient of thermal expansion of 11.5×10?6/K or less, and an 80 wt % NiFe alloy layer, is used for forming at least one of the lower shield and the upper shield. Thus, the thin film magnetic head having reduced after-record noise and reduced thermal protrusion can be obtained.
    Type: Grant
    Filed: September 18, 2003
    Date of Patent: June 13, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Shigekazu Ohtomo, Hiroshi Fukui, Sunao Yonekawa, Yoji Maruyama, Tadayuki Iwakura
  • Patent number: 7042677
    Abstract: A protrusion 24 having a width Lpfw equal to or somewhat larger than a track width Tw and protruding to the air bearing surface is provided on a lower magnetic pole 5 or lower magnetic pole front end layer 19. The lower magnetic pole 5 or the lower magnetic pole front end layer 19 other than the protrusion is retracted by Lpfd from the air bearing surface 15. With the constitution, since the upper end surface 23 of the lower magnetic pole 5 or the lower magnetic pole to end layer 19 that generates the leakage magnetic fields in the off-track portions is not exposed to the air bearing surface 15, the leakage magnetic fields Hxz in the off-track portions can be decreased greatly.
    Type: Grant
    Filed: September 18, 2003
    Date of Patent: May 9, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Shigekazu Ohtomo, Hiroshi Fukui, Nobuo Yoshida
  • Publication number: 20050122622
    Abstract: In one embodiment, a thin-film magnetic head with a write head has a lower core member made of a soft magnetic film, a planar upper core member made of a soft magnetic film, and a coil conductor positioned between the lower and upper core members. The rear end is equipped with a magnetic body, which at least magnetically joins the lower and upper core members. A magnetic pole piece is in contact with the lower core member and positioned toward an air bearing surface, which faces a recording medium. A first nonmagnetic film is provided between a pedestal magnetic pole piece and upper core member. The write head is structured so that the first nonmagnetic film constitutes a write gap. A second nonmagnetic film is provided above or below the first nonmagnetic film. The edge of the second nonmagnetic film is retracted from the air bearing surface. The upper core member's flare point is positioned toward the air bearing surface rather than the edge of the second nonmagnetic film.
    Type: Application
    Filed: September 30, 2004
    Publication date: June 9, 2005
    Applicant: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Yoji Maruyama, Tadayuki Iwakura, Makoto Morijiri, Shigekazu Ohtomo, Ichiro Ohdake
  • Publication number: 20050078412
    Abstract: A thin film head having reading part and recording part having an upper magnetic pole front end layer and a lower magnetic pole having a lower magnetic main layer, a lower magnetic pole front end portion on the lower magnetic main layer, and a projection step portion on the lower magnetic pole front end portion. The upper magnetic pole front end layer has a magnetic pole expansion position and a length from an air bearing surface to the magnetic pole expansion position is less than a length from the air bearing surface to gap depth position of the lower magnetic pole front end portion.
    Type: Application
    Filed: December 3, 2004
    Publication date: April 14, 2005
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Publication number: 20040223265
    Abstract: A magnetic material having a low coefficient of thermal expansion of 11.5×10−6/K or less is used for forming at least one of a lower shield or an upper shield. A laminated film comprising a layer of the magnetic material having a low coefficient of thermal expansion of 11.5×10−6/K or less, and an 80 wt % NiFe alloy layer, is used for forming at least one of the lower shield and the upper shield. Thus, the thin film magnetic head having reduced after-record noise and reduced thermal protrusion can be obtained.
    Type: Application
    Filed: September 18, 2003
    Publication date: November 11, 2004
    Applicant: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Shigekazu Ohtomo, Hiroshi Fukui, Sunao Yonekawa, Yoji Maruyama, Tadayuki Iwakura
  • Patent number: 6791795
    Abstract: A lower magnetic pole front end layer is formed on a lower magnetic pole main layer, and a lower magnetic pole projection layer, a recording gap layer and an upper magnetic pole front end layer each having substantially the same planar shape are formed on a planar surface of the lower magnetic pole front end layer. Trimming of a lower electrode is not necessary, and track width accuracy can be drastically improved because a resist frame is formed on the planar surface. A length of the upper magnetic pole front end layer from an air bearing surface to a head rear direction is greater than a length of the lower magnetic pole front end layer, and the rear end portion of the lower magnetic pole front end layer substantially defines a gap depth.
    Type: Grant
    Filed: August 16, 2002
    Date of Patent: September 14, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Publication number: 20040105189
    Abstract: A protrusion 24 having a width Lpfw equal to or somewhat larger than a track width Tw and protruding to the air bearing surface is provided on a lower magnetic pole 5 or lower magnetic pole front end layer 19. The lower magnetic pole 5 or the lower magnetic pole front end layer 19 other than the protrusion is retracted by Lpfd from the air bearing surface 15. With the constitution, since the upper end surface 23 of the lower magnetic pole 5 or the lower magnetic pole to end layer 19 that generates the leakage magnetic fields in the off-track portions is not exposed to the air bearing surface 15, the leakage magnetic fields Hxz in the off-track portions can be decreased greatly.
    Type: Application
    Filed: September 18, 2003
    Publication date: June 3, 2004
    Applicant: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Shigekazu Ohtomo, Hiroshi Fukui, Nobuo Yoshida
  • Publication number: 20030053251
    Abstract: There is provided a thin film magnetic head, with letting a distance of a portion, where a width of a track portion in an upper magnetic pole changes, from a flying plane from a medium be Ly, and letting a distance of a portion, where a distance between right and left of a surface portion in a lower magnetic pole in a track width direction is wider than the width of the upper magnetic pole in the track width direction, from the flying plane from a medium be Tp, by creating a thin film magnetic head that is equipped with a recording head that has a relation of Tp≦Ly, it becomes possible to reduce a needless leakage magnetic field in the track width direction with securing magnetic field strength.
    Type: Application
    Filed: September 10, 2002
    Publication date: March 20, 2003
    Inventors: Nobuo Yoshida, Ichiro Oodake, Moriaki Fuyama, Kazue Kudo, Kimitoshi Etoh, Shigekazu Ohtomo, Hiroshi Fukui
  • Publication number: 20030048581
    Abstract: A lower magnetic pole front end layer is formed on a lower magnetic pole main layer, and a lower magnetic pole projection layer, a recording gap layer and an upper magnetic pole front end layer each having substantially the same planar shape are formed on a planar surface of the lower magnetic pole front end layer. Trimming of a lower electrode is not necessary, and track width accuracy can be drastically improved because a resist frame is formed on the planar surface. A length of the upper magnetic pole front end layer from an air bearing surface to a head rear direction is greater than a length of the lower magnetic pole front end layer, and the rear end portion of the lower magnetic pole front end layer substantially defines a gap depth.
    Type: Application
    Filed: August 16, 2002
    Publication date: March 13, 2003
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Publication number: 20030021064
    Abstract: A lower magnetic pole front end portion is provided on a lower magnetic pole main layer, and then, an upper magnetic pole front end portion or an upper magnetic pole front end layer is formed on the flat surface so as to enhance the track width accuracy of thin film head. The height of the lower magnetic pole front end portion is increased so as to enhance the magnetic field intensity. A projection step portion having a width larger than that of the upper magnetic pole front end layer is provided on the lower magnetic pole front end portion. The unnecessary medium in-plane magnetic field can be thus reduced in the off-track position. The respective parts of the head are corrected, thereby realizing a high recording magnetic field intensity exceeding 716 kA/m (9000 Oe).
    Type: Application
    Filed: August 31, 2001
    Publication date: January 30, 2003
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Patent number: 6101068
    Abstract: A thin-film magnetic head includes an MR element serving as a reproducing element and a recording induction coil. The MR element is disposed between a lower magnetic pole and an intermediate magnetic pole. The recording induction coil is disposed between the intermediate magnetic pole and an upper magnetic pole. At least a portion of the upper magnetic pole in the vicinity of a recording gap is formed of a material having a high saturation magnetic flux density of 1.4 T or higher. The intermediate magnetic pole is formed of a material having a high resistivity of 80 .mu..OMEGA..multidot.cm or higher.
    Type: Grant
    Filed: September 22, 1998
    Date of Patent: August 8, 2000
    Assignee: Hitachi Metals, Ltd.
    Inventors: Shigekazu Ohtomo, Shuji Sudo, Yuji Ueda, Kuniaki Yoshimura, Hideji Takahashi