Patents by Inventor Ken-ichi Takano

Ken-ichi Takano 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: 8619510
    Abstract: A measurement method of a magnetic field gradient of a recording magnetic field generated by a magnetic head in a recording medium includes a step of locally heating the recording medium in a nonmagnetic field state where a magnetic field is not applied to the recording medium at all and measuring a temperature gradient of the recording medium in the nonmagnetic field state, a step of locally heating the recording medium in a recording magnetic field application state where the recording magnetic field is applied to the recording medium and measuring a temperature gradient of the recording medium in the recording magnetic field application state, and a step of calculating a magnetic field gradient of the recording magnetic field based on the temperature gradient of the recording medium in the nonmagnetic field state and the temperature gradient of the recording medium in the recording magnetic field application state.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: December 31, 2013
    Assignee: TDK Corporation
    Inventors: Ken-ichi Takano, Satoshi Tomikawa, Tomohito Mizuno, Hiroshi Kiyono
  • Patent number: 7180705
    Abstract: Provided is a thin film magnetic head capable of reducing expansion and bending of a recording pattern resulting from a skew so as to improve recording performance. A main pole layer comprises a laminate including a bottom main pole layer being disposed on a medium-incoming side and having a first saturated magnetic flux density and a top main pole layer being disposed on a medium-outgoing side and having a second saturated magnetic flux density larger than the first saturated magnetic flux density. When magnetic flux flows in the main pole layer, magnetic flux saturation occurs in the bottom main pole layer with a smaller saturated magnetic flux density, however, no magnetic flux saturation occurs in the top main pole layer with a larger saturated magnetic flux density, so the magnetic flux flows mainly in the top main pole layer on a priority basis.
    Type: Grant
    Filed: April 3, 2003
    Date of Patent: February 20, 2007
    Assignees: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Naoto Matono, Shigeru Shoji, Ken-ichi Takano
  • Patent number: 7027271
    Abstract: A magnetoresisive device comprises an MR element, bias field applying layers located adjacent to the side portions of the MR element, and two electrode layers that feed a sense current to the MR element. The electrode layers overlap one of the surfaces of the MR element. The total overlap amount of the two electrode layers is smaller than 0.3 ?m. The MR element is a spin-valve GMR element. The MR element incorporates a base layer, a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a cap layer that are stacked in this order. The pinned layer includes a nonmagnetic spacer layer, and two ferromagnetic layers that sandwich this spacer layer.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: April 11, 2006
    Assignee: TDK Corporation
    Inventors: Kenji Inage, Yoshihiro Kudo, Ken-ichi Takano, Koichi Terunuma, Yuzuru Iwai
  • Patent number: 6731474
    Abstract: Provided are a thin film magnetic head and a method of manufacturing the same, which is capable of high density recording and obtaining stable output. The thin film magnetic head includes an MR film sandwiched in between first and second shield layers. The first shield layer includes an inner layer, a magnetization stabilizing layer, an underlayer, and an outer layer laminated in order from the MR film. The second shield layer includes an inner layer, a magnetization stabilizing layer, an isolating layer, and an outer layer laminated in order from the MR film. The magnetization stabilizing layers are formed of antiferromagnetic material, so as to control the direction of magnetization of the inner layers.
    Type: Grant
    Filed: November 26, 2001
    Date of Patent: May 4, 2004
    Assignee: TDK Corporation
    Inventors: Koichi Terunuma, Ken-ichi Takano, Noriyuki Ito
  • Patent number: 6707294
    Abstract: A method and computer program to calculate a reproduction track width of a MR head. This method begins by subdividing the magnetic domain control layer of a MR element and lead conductors into several polyhedral elements. Thereafter, electric potentials are calculated for each of the polyhedral elements based on the resistance at each layer. A current density is determined for each of the polyhedral elements based on the calculated electric potentials. The current densities are integrated to calculate an initial resistance value. Further, the resistance of a local block is changed by a predetermined amount. The electric potential is calculated for each of the polyhedral elements, current density is acquired, and the acquired current densities is calculated to determine a resistance value. Finally, the reproduction track width is obtained based on the initial acquired resistance value and the acquired resistance value.
    Type: Grant
    Filed: June 19, 2002
    Date of Patent: March 16, 2004
    Assignee: TDK Corporation
    Inventor: Ken-ichi Takano
  • Patent number: 6700368
    Abstract: A method of analyzing characteristics of a magnetic transducer includes sub-dividing a region to be analyzed in a magnetic transducer into a plurality of polyhedral elements, and performing a transient calculation. The transient calculation includes calculating a transient electric field of each polyhedral element, calculating a transient magnetic field of each polyhedral element, and updating the magnetic permeability in accordance with a magnetic flux density determined from the calculated transient magnetic field. The steps of performing transient calculation are repeated until a predetermined number of time steps have been completed, in order to determine electric fields and magnetic fields of all of the plurality of polyhedral elements in the region to be analyzed.
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: March 2, 2004
    Assignee: TDK Corporation
    Inventor: Ken-ichi Takano
  • Publication number: 20030193742
    Abstract: Provided is a thin film magnetic head capable of reducing expansion and bending of a recording pattern resulting from a skew so as to improve recording performance. A main pole layer comprises a laminate including a bottom main pole layer being disposed on a medium-incoming side and having a first saturated magnetic flux density and a top main pole layer being disposed on a medium-outgoing side and having a second saturated magnetic flux density larger than the first saturated magnetic flux density. When magnetic flux flows in the main pole layer, magnetic flux saturation occurs in the bottom main pole layer with a smaller saturated magnetic flux density, however, no magnetic flux saturation occurs in the top main pole layer with a larger saturated magnetic flux density, so the magnetic flux flows mainly in the top main pole layer on a priority basis.
    Type: Application
    Filed: April 3, 2003
    Publication date: October 16, 2003
    Applicants: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Naoto Matono, Shigeru Shoji, Ken-Ichi Takano
  • Publication number: 20030083832
    Abstract: A method of analyzing characteristics of a magnetic transducer includes sub-dividing a region to be analyzed in a magnetic transducer into a plurality of polyhedral elements, and performing a transient calculation. The transient calculation includes calculating a transient electric field of each polyhedral element, calculating a transient magnetic field of each polyhedral element, and updating the magnetic permeability in accordance with a magnetic flux density determined from the calculated transient magnetic field. The steps of performing transient calculation are repeated until a predetermined number of time steps have been completed, in order to determine electric fields and magnetic fields of all of the plurality of polyhedral elements in the region to be analyzed.
    Type: Application
    Filed: July 11, 2002
    Publication date: May 1, 2003
    Applicant: TDK Corporation
    Inventor: Ken-ichi Takano
  • Publication number: 20030011361
    Abstract: A method and computer program to calculate a reproduction track width of an MR head. This method begins by subdividing the magnetic domain control layer of an MR element and lead conductors into several polyhedral elements. Thereafter, electric potentials are calculated for each of the polyhedral elements based on the resistance at each layer. A current density is determined for each of the polyhedral elements based on the calculated electric potentials. The current densities are integrated to calculate an initial resistance value. Further, the resistance of a local block is changed by a predetermined amount. The electric potential is calculated for each of the polyhedral elements, current density is acquired, and the acquired current densities is calculated to determine a resistance value. Finally, the reproduction track width is obtained based on the initial acquired resistance value and the acquired resistance value.
    Type: Application
    Filed: June 19, 2002
    Publication date: January 16, 2003
    Applicant: TDK Corporation
    Inventor: Ken-ichi Takano
  • Patent number: 6469868
    Abstract: It is an object of the invention to improve characteristics of a thin-film magnetic head in the case where the frequency of data to write is high, in particular. In a thin-film magnetic head of the invention a nonmagnetic conductive member is provided to face at least part of a top pole layer of an induction-type magnetic transducer. Consequently, eddy currents are induced inside the nonmagnetic conductive member by a write current. The eddy currents suppress a magnetic field leaking from magnetic layers. In addition, the nonmagnetic conductive member is in contact with the top pole layer. Therefore, eddy currents generated inside the top pole layer are fed to the nonmagnetic conductive member, too.
    Type: Grant
    Filed: September 2, 1999
    Date of Patent: October 22, 2002
    Assignee: TDK Corporation
    Inventors: Takahiro Yamamoto, Noboru Yamanaka, Ken-ichi Takano
  • Publication number: 20020126423
    Abstract: Provided are a thin film magnetic head and a method of manufacturing the same, which is capable of high density recording and obtaining stable output. The thin film magnetic head comprises an MR film sandwiched in between first and second shield layers. The first shield layer includes an inner layer, a magnetization stabilizing layer, an underlayer, and an outer layer laminated in order from the MR film. The second shield layer includes an inner layer, a magnetization stabilizing layer, an isolating layer, and an outer layer laminated in order from the MR film. The magnetization stabilizing layers are formed of antiferromagnetic material, so as to control the direction of magnetization of the inner layers.
    Type: Application
    Filed: November 26, 2001
    Publication date: September 12, 2002
    Applicant: TDK CORPORATION
    Inventors: Koichi Terunuma, Ken-ichi Takano, Noriyuki Ito
  • Patent number: 6426853
    Abstract: An MR sensor, a thin-film magnetic head and a thin-film wafer with a plurality of the thin-film magnetic heads having a MR multi-layered structure including a non-magnetic material layer, first and second ferromagnetic material layers (free and pinned layers) separated by the non-magnetic material layer, and an anti-ferromagnetic material layer formed adjacent to and in physical contact with one surface of the pinned layer, the one surface being on an opposite side of the pinned layer from the non-magnetic material layer, the multi-layered structure having ends in a direction parallel to a magnetically sensitive surface or an ABS, and longitudinal bias layers formed at both the ends of the MR multi-layered structure, for providing a longitudinal magnetic bias to the MR multi-layered structure. The MR multi-layered structure is shaped such that a magnetization direction of the pinned layer is inclined at an angle from an axis of easy magnetization of the pinned layer.
    Type: Grant
    Filed: November 15, 1999
    Date of Patent: July 30, 2002
    Assignee: TDK Corporation
    Inventors: Masanori Sakai, Ken-ichi Takano, Yuzuru Iwai
  • Publication number: 20020041464
    Abstract: It is an object of the invention to improve characteristics of a thin-film magnetic head in the case where the frequency of data to write is high, in particular. In a thin-film magnetic head of the invention a nonmagnetic conductive member is provided to face at least part of a top pole layer of an induction-type magnetic transducer. Consequently, eddy currents are induced inside the nonmagnetic conductive member by a write current. The eddy currents suppress a magnetic field leaking from magnetic layers. In addition, the nonmagnetic conductive member is in contact with the top pole layer. Therefore, eddy currents generated inside the top pole layer are fed to the nonmagnetic conductive member, too.
    Type: Application
    Filed: September 2, 1999
    Publication date: April 11, 2002
    Inventors: TAKAHIRO YAMAMOTO, NOBORU YAMANAKA, KEN-ICHI TAKANO
  • Publication number: 20020036497
    Abstract: A magnetoresisive device comprises an MR element, bias field applying layers located adjacent to the side portions of the MR element, and two electrode layers that feed a sense current to the MR element. The electrode layers overlap one of the surfaces of the MR element. The total overlap amount of the two electrode layers is smaller than 0.3 &mgr;m. The MR element is a spin-valve GMR element. The MR element incorporates a base layer, a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a cap layer that are stacked in this order. The pinned layer includes a nonmagnetic spacer layer, and two ferromagnetic layers that sandwich this spacer layer.
    Type: Application
    Filed: July 25, 2001
    Publication date: March 28, 2002
    Applicant: TDK CORPORATION
    Inventors: Kenji Inage, Yoshihiro Kudo, Ken-ichi Takano, Koichi Terunuma, Yuzuru Iwai
  • Publication number: 20020036874
    Abstract: A magnetoresisive device comprises an MR element, bias field applying layers located adjacent to the side portions of the MR element, and two electrode layers that feed a sense current to the MR element. The electrode layers overlap one of the surfaces of the MR element. The total overlap amount of the two electrode layers is smaller than 0.3 &mgr;m. The MR element is a spin-valve GMR element. The MR element incorporates a base layer, a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a cap layer that are stacked in this order. The pinned layer includes a nonmagnetic spacer layer, and two ferromagnetic layers that sandwich this spacer layer.
    Type: Application
    Filed: July 25, 2001
    Publication date: March 28, 2002
    Applicant: TDK CORPORATION
    Inventors: Kenji Inage, Yoshihiro Kudo, Ken-ichi Takano, Koichi Terunuma, Yuzuru Iwai
  • Patent number: 6333828
    Abstract: A magnetic disk unit includes slider suspension assemblies, each of the assemblies having a slider with at least one magnetic head element and a suspension with one end portion and one surface, the slider being mounted on the one surface of the suspension at the one end portion, magnetic disks, each of the disks having at least one surface which opposes to the slider of the assembly, head IC chips electrically connected to the magnetic head elements, and a control circuit electrically connected with the head IC chips. The control circuit controls operations of each of the magnetic head elements so that the write current is applied to the magnetic head element for a first predetermined period of time and then the application of the write current to the magnetic head element is stopped for a second predetermined period of time which is equal to or longer than the first predetermined period.
    Type: Grant
    Filed: April 5, 1999
    Date of Patent: December 25, 2001
    Assignee: TDK Corporation
    Inventors: Haruyuki Morita, Masanori Sakai, Ken-ichi Takano
  • Patent number: 6270588
    Abstract: A thin-film magnetic head having a spin valve effect multi-layered structure including a non-magnetic electrically conductive material layer, first and second ferromagnetic material layers separated by the non-magnetic electrically conductive material layer, and an anti-ferromagnetic material layer formed adjacent to and in physical contact with one surface of the second ferromagnetic material layer. This one surface is an opposite side from the non-magnetic electrically conductive material layer and the multi-layered structure has ends at its track-width direction. The head also has longitudinal bias means formed at both the track-width ends of the multi-layered structure, for providing a longitudinal magnetic bias to the multi-layered structure.
    Type: Grant
    Filed: March 19, 1999
    Date of Patent: August 7, 2001
    Assignee: TDK Corporation
    Inventors: Ken-ichi Takano, Masato Takahashi, Nobuya Oyama
  • Patent number: 6268980
    Abstract: A magnetic head apparatus includes a slider with at least one magnetic head element, a suspension having one end portion, one surface and connection pads formed on the one surface, for supporting the slider at the one end portion, a head IC chip flip chip bonded on the connection pads, and an overcoat layer formed on the one surface of the suspension to cover at least a part of each of the connection pads, the overcoat layer with anti-running structures for controlling flow of solder while the IC chip is flip chip bonded.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: July 31, 2001
    Assignee: TDK Corporation
    Inventors: Masashi Shiraishi, Masanori Sakai, Tsuyoshi Umehara, Haruyuki Morita, Ken-ichi Takano
  • Patent number: 6202288
    Abstract: A method for manufacturing a magnetic head suspension assembly includes a step of forming a plurality of flexure pieces coupled with each other and kept substantially flat, each of the flexure pieces being provided with conductive connection pattern, a step of mounting head IC chips on the respective substantially flat flexure pieces, the mounting being executed before fixing of said flexure pieces to load beams, and a step of separating said flexure pieces with the head IC chips into individual pieces.
    Type: Grant
    Filed: August 30, 1999
    Date of Patent: March 20, 2001
    Assignee: TDK Corporation
    Inventors: Masashi Shiraishi, Masanori Sakai, Tsuyoshi Umehara, Haruyuki Morita, Ken-ichi Takano
  • Patent number: 6173485
    Abstract: A method for manufacturing a magnetic head apparatus includes a step of forming a plurality of flexure pieces coupled with each other and kept in substantially flat, each of the flexure pieces being provided with conductive connection pattern, a step of mounting sliders with magnetic head elements on the respective flexure pieces, or mounting head IC chips on the respective flexure pieces and after that mounting sliders with magnetic head elements on the respective flexure pieces, and a step of separating the flexure pieces with the sliders into individual pieces.
    Type: Grant
    Filed: December 21, 1998
    Date of Patent: January 16, 2001
    Assignee: TDK Corporation
    Inventors: Masashi Shiraishi, Masanori Sakai, Tsuyoshi Umehara, Haruyuki Morita, Ken-ichi Takano