Patents by Inventor Tetsuya Kuwashima

Tetsuya Kuwashima 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: 8240026
    Abstract: A method for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.
    Type: Grant
    Filed: September 24, 2008
    Date of Patent: August 14, 2012
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
  • Patent number: 8125743
    Abstract: A thin-film magnetic head has a magnetoresistive effect read head element. The magnetoresistive effect read head element includes a lower shield layer, an upper shield layer, and a magnetoresistive effect layer formed between the lower shield layer and the upper shield layer. The magnetoresistive effect read head element also includes a lower antiferromagnetic layer. The lower antiferromagnetic layer is contacted with the lower shield layer only at an edge area of the lower shield layer.
    Type: Grant
    Filed: June 8, 2007
    Date of Patent: February 28, 2012
    Assignee: TDK Corporation
    Inventors: Naoki Ohta, Kosuke Tanaka, Takayasu Kanaya, Kazuki Sato, Yasufumi Uno, Tetsuya Kuwashima
  • Patent number: 7978438
    Abstract: A thin-film magnetic head provided with at least one MR read head element includes a lower shield layer, an upper shield layer, and an MR layer formed between the lower shield layer and the upper shield layer. A profile of the upper shield layer, appeared at an ABS, has obtuse or rounded upper corners at end edges of the upper shield layer along a track-width direction.
    Type: Grant
    Filed: July 9, 2007
    Date of Patent: July 12, 2011
    Assignee: TDK Corporation
    Inventors: Naoki Ohta, Kosuke Tanaka, Takayasu Kanaya, Kazuki Sato, Yasufumi Uno, Tetsuya Kuwashima
  • Patent number: 7933099
    Abstract: A magnetic head having precisely controlled MR height has a slider substrate and a magnetic head part provided on the slider substrate. The magnetic head part includes, seeing from a medium-opposing surface side, a magnetism detecting element; an upper magnetic shield layer arranged on the magnetism detecting element; an electrode layer separated in a track width direction from the upper magnetic shield layer; and a conductor layer, arranged closer to the slider substrate than are the upper magnetic shield layer and electrode layer, extending in the track width direction so as to be in contact with the upper magnetic shield layer and electrode layer and forming a part of the medium-opposing surface.
    Type: Grant
    Filed: April 11, 2007
    Date of Patent: April 26, 2011
    Assignee: TDK Corporation
    Inventors: Naoki Ohta, Tetsuya Kuwashima, Kazuki Sato, Kosuke Tanaka
  • Patent number: 7916434
    Abstract: A TMR effect element with sufficiently reduced element resistance and restricted popping noise is provided, which comprises a tunnel barrier layer formed primarily of a metal oxide including many electric charge sites. The electric charge sites density n and the mobility ? of electrons trapped due to the electric charge sites satisfy a relationship expressed by: 0<(ns1?1?ns2?1)?1·(?0??)·(n?)?1<0.2, where ns1 and ns2 are densities of tunnel electrons when an element resistance is a minimum and maximum respectively during reading signals and ?0 is the mobility of electrons when not trapped.
    Type: Grant
    Filed: March 24, 2006
    Date of Patent: March 29, 2011
    Assignee: TDK Corporation
    Inventors: Shunji Saruki, Kenji Inage, Tetsuya Kuwashima, Hiroshi Kiyono, Katsumichi Tagami, Kazumasa Fukuda, Masahide Kohno
  • Patent number: 7911745
    Abstract: A thin-film magnetic head includes a magneto-resistive effect device of the CPP structure including a multilayer film comprising a stack of a fixed magnetization layer, a nonmagnetic layer and a free layer stacked one upon another in order, with a sense current applied in the stacking direction of the multilayer film, and an upper shield layer and a lower shield layer with the magneto-resistive effect device held between them in the thickness direction, and further comprises a bias magnetic field-applying layer located at each end of the multilayer film in the widthwise direction and a re-magnetizer unit designed such that when the bias magnetic field-applying layers malfunction, they are re-magnetized to go back to normal.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: March 22, 2011
    Assignee: TDK Corporation
    Inventors: Yosuke Antoku, Tsuyoshi Umehara, Tetsuya Kuwashima
  • Patent number: 7894168
    Abstract: The invention provides a thin-film magnetic head having a magneto-resistive effect device of the CPP (current perpendicular to plane) structure comprising a multilayer film in which a fixed magnetization layer, a nonmagnetic layer and a free layer are stacked together in order. The fixed magnetization layer, nonmagnetic layer and free layer extend away from an air bearing surface that is a plane in opposition to a medium, the length of the fixed magnetization layer in a depth direction normal to said air bearing surface is greater than the length of the free layer in the depth direction. A shunt layer for shunting the sense current is located at a farther distance in the depth direction than the free layer, and the shunt layer is separated from the free layer by a constant gap in the depth direction.
    Type: Grant
    Filed: August 28, 2007
    Date of Patent: February 22, 2011
    Assignee: TDK Corporation
    Inventors: Hiroshi Kiyono, Tetsuya Kuwashima
  • Patent number: 7784171
    Abstract: A method is provided for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: August 31, 2010
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
  • Patent number: 7743666
    Abstract: A tunneling effect element, including an insulating layer that forms a tunneling barrier, a lower electrode that is conductive and non-magnetic, and is formed on a bottom surface of said insulating layer, an upper electrode that is conductive and non-magnetic, and is formed on a top surface of said insulating layer, and a transmission member. The transmission member is made of insulating material that is formed surrounding the insulating layer and the lower and upper electrodes. The transmission member is also formed on a surface of an object to be detected, and transmits deformation of the object to be detected to the insulating layer. The tunneling effect element detects a change in stress of the object to be detected as a change in electric resistance.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: June 29, 2010
    Assignee: TDK Corporation
    Inventors: Tetsuya Kuwashima, Naoki Ohta
  • Patent number: 7672084
    Abstract: Composite thin-film magnetic head includes a substrate; a first insulation layer on the substrate; an MR read head element on the first insulation layer and provided with a lower shield layer, an upper shield layer and an MR layer with a sense current flowing perpendicular to a surface of the MR layer though the upper and lower shield layers; a second insulation layer on the MR read head element; an inductive write head element on the second insulation layer and provided with a lower magnetic pole layer, a recording gap layer, an upper magnetic pole layer with end portion opposed to an end portion of the lower magnetic pole layer through the recording gap layer and a write coil; and a nonmagnetic conductive layer electrically conducted with the lower shield layer and opposed to the substrate to increase the electrode area between the lower shield layer and the substrate.
    Type: Grant
    Filed: April 21, 2009
    Date of Patent: March 2, 2010
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Noriaki Kasahara, Tetsuya Kuwashima
  • Patent number: 7672087
    Abstract: Provided is an MR effect element in which the magnetization of the pinned layer is stably fixed even after going through high temperature process. The MR effect element comprises: a non-magnetic intermediate layer; a pinned layer and a free layer stacked so as to sandwich the non-magnetic intermediate layer; an antiferromagnetic layer stacked to have a surface contact with the pinned layer, for fixing a magnetization of the pinned layer to a direction in-plane of the pinned layer and perpendicular to a track width direction; and hard bias layers provided on both sides in the track width direction of the free layer, for applying a bias field to the free layer, a product ?S×? of a saturation magnetostriction constant ?S of the pinned layer and an internal stress ? on a cross-section perpendicular to a layer surface of the hard bias layer being negative.
    Type: Grant
    Filed: March 27, 2007
    Date of Patent: March 2, 2010
    Assignee: TDK Corporation
    Inventors: Takayasu Kanaya, Katsuki Kurihara, Tetsuya Kuwashima
  • Patent number: 7583462
    Abstract: Timely and proper flying height adjustment is achieved using a controller, which is designed for a magnetic recording and reproducing apparatus that does not use a magnetic head having a heating element for flying height adjustment without any modification. A head amplifier includes a write amplifier for applying a write current to a write head element, a read amplifier for amplifying a read voltage output from a read head element and outputting a read signal, a heating element driver for applying a heat generating current to at least one heating element for adjusting a flying height, and a heat controller for controlling the heating element driver.
    Type: Grant
    Filed: September 6, 2007
    Date of Patent: September 1, 2009
    Assignee: TDK Corporation
    Inventors: Naoki Ohta, Tetsuya Kuwashima
  • Patent number: 7542245
    Abstract: Composite thin-film magnetic head includes a substrate; a first insulation layer on the substrate; an MR read head element on the first insulation layer and provided with a lower shield layer, an upper shield layer and an MR layer with a sense current flowing perpendicular to a surface of the MR layer though the upper and lower shield layers; a second insulation layer on the MR read head element; an inductive write head element on the second insulation layer and provided with a lower magnetic pole layer, a recording gap layer, an upper magnetic pole layer with end portion opposed to an end portion of the lower magnetic pole layer through the recording gap layer and a write coil; and a nonmagnetic conductive layer electrically conducted with the lower shield layer and opposed to the substrate to increase the electrode area between the lower shield layer and the substrate.
    Type: Grant
    Filed: February 7, 2006
    Date of Patent: June 2, 2009
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Noriaki Kasahara, Tetsuya Kuwashima
  • Patent number: 7520165
    Abstract: Highly efficient and highly sensitive sensors of small size are provided in desired position, desired shape and size for a micro structure that causes elastic deformation at least a part thereof. Moreover, utilizing the sensors allows facilitating to assemble and adjust the components, miniaturizing and simplifying the detection circuit, and measuring a local displacement of a fine part of the micro structure. A micro structure is a cantilever in which a beam part causes elastic deformation. This cantilever includes a sensor detecting elastic deformation of a beam part by tunneling effect.
    Type: Grant
    Filed: June 7, 2006
    Date of Patent: April 21, 2009
    Assignee: TDK Corporation
    Inventors: Naoki Ohta, Tetsuya Kuwashima
  • Publication number: 20090059436
    Abstract: The invention provides a thin-film magnetic head having a magneto-resistive effect device of the CPP (current perpendicular to plane) structure comprising a multilayer film in which a fixed magnetization layer, a nonmagnetic layer and a free layer are stacked together in order. The fixed magnetization layer, nonmagnetic layer and free layer extend rearward from an air bearing surface that is a plane in opposition to a medium, the length of the depth-wise side of the fixed magnetization layer is longer than that of the free layer, and a shunt layer for shunting a sense current is formed more on the depth-wise side of, and kept constantly away from, the free layer. There are thus much more favorable advantages obtained: even when device size is further reduced and narrowed, degradation of frequency characteristics is hold back, any increase in the thermal magnetic noise is stayed off, and performance fluctuations are minimized.
    Type: Application
    Filed: August 28, 2007
    Publication date: March 5, 2009
    Applicant: TDK CORPORATION
    Inventors: Hiroshi Kiyono, Tetsuya Kuwashima
  • Publication number: 20090052089
    Abstract: The thin-film magnetic head of the invention comprises a magneto-resistive effect device of the CPP (current perpendicular to plane) structure including a multilayer film comprising a stack of a fixed magnetization layer, a nonmagnetic layer and a free layer stacked one upon another in order, with a sense current applied in the stacking direction of the multilayer film, and an upper shield layer and a lower shield layer with the magneto-resistive effect device held between them in the thickness direction, and further comprises a bias magnetic field-applying layer located at each end of the multilayer film in the widthwise direction and a re-magnetizer unit designed such that when the bias magnetic field-applying layers malfunction, they are re-magnetized to go back to normal.
    Type: Application
    Filed: August 24, 2007
    Publication date: February 26, 2009
    Applicant: TDK CORPORATION
    Inventors: Yosuke Antoku, Tsuyoshi Umehara, Tetsuya Kuwashima
  • Publication number: 20090038143
    Abstract: A method is provided for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.
    Type: Application
    Filed: September 24, 2008
    Publication date: February 12, 2009
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
  • Publication number: 20080253033
    Abstract: A magnetic head in which the size of MR height is controlled precisely, a head gimbal assembly and a hard disk drive which are mounted with such a magnetic head, and a method of making a magnetic head in which the size of MR height is controlled precisely. The magnetic head in accordance with the present invention is a magnetic head comprising a slider substrate and a magnetic head part provided on the slider substrate; wherein the magnetic head part comprises, seeing from a medium-opposing surface side, a magnetism detecting element; an upper magnetic shield layer arranged on the magnetism detecting element; an electrode layer separated in a track width direction from the upper magnetic shield layer; and a conductor layer, arranged closer to the slider substrate than are the upper magnetic shield layer and electrode layer, extending in the track width direction so as to be in contact with the upper magnetic shield layer and electrode layer and forming a part of the medium-opposing surface.
    Type: Application
    Filed: April 11, 2007
    Publication date: October 16, 2008
    Applicant: TDK CORPORATION
    Inventors: Naoki Ohta, Tetsuya Kuwashima, Kazuki Sato, Kosuke Tanaka
  • Patent number: 7436633
    Abstract: A parasitic capacity C4 generated between a slider substrate and the first shield layer with the first insulating layer as a capacity layer is made substantially equal to a parasitic capacity C2 occurring between a lower magnetic layer and the second shield layer with the third insulating layer as a capacity layer. Preferably, a connection is made between the lower magnetic layer and the slider substrate by a resistance of preferably 100 (?) or lower. Thus, it is possible to provide a thin-film magnetic head that can hold back deterioration in a reproducing device and the occurrence of errors due to crosstalk between a recording device and the reproducing device and extraneous noises.
    Type: Grant
    Filed: August 17, 2005
    Date of Patent: October 14, 2008
    Assignee: TDK Corporation
    Inventors: Hiroshi Kiyono, Tetsuya Kuwashima, Takeo Kagami, Noriaki Kasahara, Naoki Ohta, Nozomu Hachisuka
  • Publication number: 20080239582
    Abstract: Provided is an MR effect element in which the magnetization of the pinned layer is stably fixed even after going through high temperature process. The MR effect element comprises: a non-magnetic intermediate layer; a pinned layer and a free layer stacked so as to sandwich the non-magnetic intermediate layer; an antiferromagnetic layer stacked to have a surface contact with the pinned layer, for fixing a magnetization of the pinned layer to a direction in-plane of the pinned layer and perpendicular to a track width direction; and hard bias layers provided on both sides in the track width direction of the free layer, for applying a bias field to the free layer, a product ?S×? of a saturation magnetostriction constant ?S of the pinned layer and an internal stress ? on a cross-section perpendicular to a layer surface of the hard bias layer being negative.
    Type: Application
    Filed: March 27, 2007
    Publication date: October 2, 2008
    Applicant: TDK CORPORATION
    Inventors: Takayasu Kanaya, Katsuki Kurihara, Tetsuya Kuwashima