Patents by Inventor Koji Shimazawa

Koji Shimazawa 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: 20110216634
    Abstract: A plasmon generator has a near-field light generating part located in a medium facing surface. The plasmon generator has an outer surface including a plasmon exciting surface and a plasmon propagating surface that face toward opposite directions. The plasmon exciting surface is substantially in contact with an evanescent light generating surface of a waveguide's core. The plasmon propagating surface is in contact with a dielectric layer that has a refractive index lower than that of the core. The plasmon exciting surface includes a first width changing portion. The plasmon propagating surface includes a second width changing portion. Each of the first and second width changing portions has a width that decreases with decreasing distance to the medium facing surface, the width being in a direction parallel to the medium facing surface and the evanescent light generating surface.
    Type: Application
    Filed: March 8, 2010
    Publication date: September 8, 2011
    Applicant: TDK CORPORATION
    Inventors: Tsutomu Chou, Eiji Komura, Koji Shimazawa, Shinji Hara
  • Patent number: 8014101
    Abstract: A near-field light generator plate 36 of the present invention is arranged to face a medium 10, and one portion 36b and other portion 36a in a medium-facing surface S thereof are made of their respective electroconductive materials different from each other. Since the one portion and the other portion in the medium-facing surface are made of the electroconductive materials different from each other, this medium-facing surface is formed by a surface removing step such as polishing or etching from the medium-facing surface side so that a difference between heights of the one portion and the other portion is readily made based on the difference of the materials.
    Type: Grant
    Filed: December 19, 2007
    Date of Patent: September 6, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Kosuke Tanaka
  • Patent number: 8014108
    Abstract: The invention provides a magnetoresistive device of the CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first shield layer and a second shield layer which are located and formed such that the magnetoresistive unit is sandwiched between them from above and below, with a sense current applied in the stacking direction, wherein said magnetoresistive unit comprises a non-magnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that said nonmagnetic intermediate layer is sandwiched between them.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: September 6, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Tsutomu Chou, Daisuke Miyauchi
  • Publication number: 20110205661
    Abstract: An optical waveguide of the present invention is an optical waveguide in order to directly introduce light beams emitted from a light emitting element. In a core that is a waveguide through which light propagates, a concave part is formed that is a depression in a light incident end surface that is one side where light enters. Therefore, an optical waveguide is realized that can obtain a large optical coupling efficiency is possible by the operation of phase alignment in the concave part.
    Type: Application
    Filed: February 25, 2010
    Publication date: August 25, 2011
    Applicant: TDK CORPORATION
    Inventors: Eiji Komura, Koji Shimazawa, Kosuke Tanaka
  • Publication number: 20110205860
    Abstract: A plasmon generator has an outer surface including a surface plasmon exciting surface, and has a near-field light generating part located in a medium facing surface. The surface plasmon exciting surface is a flat surface that faces an evanescent light generating surface of a waveguide with a predetermined distance therebetween. The surface plasmon exciting surface includes a width changing portion. The width of the width changing portion in a direction parallel to the medium facing surface and the evanescent light generating surface decreases with decreasing distance to the medium facing surface. A magnetic pole is located at such a position that the plasmon generator is interposed between the magnetic pole and the waveguide. The outer surface of the plasmon generator includes a pole contact surface that is in contact with the magnetic pole.
    Type: Application
    Filed: February 22, 2010
    Publication date: August 25, 2011
    Applicant: TDK CORPORATION
    Inventors: Tsutomu CHOU, Eiji KOMURA, Koji SHIMAZAWA, Kosuke TANAKA, Daisuke MIYAUCHI
  • Publication number: 20110205660
    Abstract: A spot size converter according to the present invention is capable of shortening the waveguide length in the spot size converter and of promoting a size reduction of the optical waveguide itself because two cores having a taper portion are combined and those tapering angles are mutually aligned. Furthermore, spot size conversion efficiency is favorable even in a small size.
    Type: Application
    Filed: February 25, 2010
    Publication date: August 25, 2011
    Applicant: TDK CORPORATION
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa, Seiichi Takayama
  • Patent number: 8000175
    Abstract: A thermally assisted magnetic head includes: a slider having a medium-facing surface; and a surface-emitting semiconductor laser. The slider has: a slider substrate, on which part of the medium-facing surface is formed; and a magnetic head portion, on which another part of the medium-facing surface is formed, and which has a first surface in contact with a head stacking surface of the slider substrate and a second surface opposite the first surface. The magnetic head portion has: a main magnetic pole that generates a write magnetic field from an end face on the side of the medium-facing surface; an optical waveguide core extending along the first surface and having a light exit surface at the medium-facing surface; and a diffraction grating, which is provided in the optical waveguide core or further towards the second surface than the optical waveguide core, and the refractive index of which varies periodically along the direction in which the optical waveguide core extends.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: August 16, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Eiji Komura, Seiichi Takayama
  • Patent number: 8000178
    Abstract: Provided is a surface plasmon antenna that can be set so that the emitting position on the end surface of the plasmon antenna where near-field light is emitted is located sufficiently close to the end of a magnetic pole. The surface plasmon antenna comprises an edge having a portion for coupling with a light in a surface plasmon mode. The edge is provided for propagating surface plasmon excited by the light and extends from the portion to a near-field light generating end surface that emits near-field light. The edge for propagating surface plasmon is a very narrow propagation region. Therefore, the near-field light generating end surface, which appears as a polished surface processed through polishing in the manufacturing of the plasmon antenna, can be made a shape with a very small size, and further can be set so that surface plasmon propagates to reach the end surface reliably.
    Type: Grant
    Filed: October 29, 2008
    Date of Patent: August 16, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Eiji Komura, Yasuhiro Ito, Seiichi Takayama, Satoshi Tomikawa, Daisuke Miyauchi, Kosuke Tanaka
  • Publication number: 20110167616
    Abstract: Provided is a material for tactile sensor, which is easy to be formed, and in which the shape, size and orientation of coils dispersed in the medium are sufficiently controlled. The tactile-sensitive material comprises a medium and a plurality of micro coils dispersed in the medium and constituting a LCR resonance circuit, and wherein each of the plurality of micro coils comprises at least one spiral coil portion, and coil axes of the plurality of micro coils are aligned along at least one direction and/or directed in at least one plane. When a tactile stress is applied to the tactile-sensitive material, the C component is varied significantly, which contributes to the improvement in sensitivity of the tactile sensor. Further, by providing a core at the coil center, the sensitivity is more improved.
    Type: Application
    Filed: November 17, 2010
    Publication date: July 14, 2011
    Applicant: TDK CORPORATION
    Inventor: Koji SHIMAZAWA
  • Publication number: 20110164479
    Abstract: Provided is a thermally-assisted magnetic recording head comprising a near-field-light-generating (NFL-generating) optical system with an improved light use efficiency. The head comprises a magnetic pole, a waveguide propagating a light for exciting surface plasmon, and a NF-optical device configured to emit NF-light from its end surface located adjacent to the magnetic pole end surface. The waveguide cross-section, taken by a plane perpendicular to a waveguide edge along elongated direction, has substantially a trapezoidal shape in which a longer side of opposed parallel sides is an edge of the cross-section on the NF-optical device side. This configuration enables a coupled portion of the NF-optical device which is coupled with the light to be placed in the effective distribution range of the light seeping from the waveguide. Consequently, there can be realized a sufficiently strong coupling between the light seeping from the waveguide and the NF-optical device.
    Type: Application
    Filed: January 6, 2010
    Publication date: July 7, 2011
    Applicant: TDK CORPORATION
    Inventors: Eiji KOMURA, Tsutomu CHOU, Koji SHIMAZAWA, Kosuke TANAKA
  • Patent number: 7974043
    Abstract: A thermally assisted magnetic head has a slider having a medium-facing surface, and a light source unit having a light source support substrate, and a light source disposed on the light source support substrate; the slider has a slider substrate and a magnetic head portion disposed on a side surface of the slider substrate; the magnetic head portion has a magnetic recording element for generating a magnetic field, first and second waveguides, for receiving light through an end face and guiding the light to the medium-facing surface, and a near-field light generator disposed on an end face; the light source support substrate is fixed to a surface of the slider substrate so that light emitted from the light source can enter the end face of the first waveguide.
    Type: Grant
    Filed: August 29, 2007
    Date of Patent: July 5, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Kosuke Tanaka, Takaaki Domon
  • Patent number: 7974048
    Abstract: The invention provides a magneto-resistive effect device of the CPP (current perpendicular to plane) structure, having a magneto-resistive effect unit, and a first shield layer and a second shield layer located and formed such that the magneto-resistive effect unit is sandwiched between them, with a sense current applied in a stacking direction.
    Type: Grant
    Filed: November 28, 2007
    Date of Patent: July 5, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Daisuke Miyauchi, Yoshihiro Tsuchiya, Takahiko Machita, Shinji Hara
  • Publication number: 20110157738
    Abstract: A method for manufacturing a thermally-assisted magnetic recording head is provided, in which joined are: a light source unit that includes a light source having a surface including a light-emission center on the joining surface side of a unit substrate; and a slider that includes an optical system having a light-receiving end surface reaching a back surface opposite to the opposed-to-medium surface. This method utilizes “semi-active alignment” that uses an alignment light, and comprises steps of: causing a light to enter the light source from a surface opposite to the light-emission center; detecting the light that has passed through the light source and is emitted from the light-emission center to align the light-emission center with the light-receiving end surface of the slider; and bonding the light source unit to the slider. This manufacturing method can achieve the alignment with a sufficiently high alignment accuracy in a short processing time.
    Type: Application
    Filed: December 28, 2009
    Publication date: June 30, 2011
    Applicant: TDK CORPORATION
    Inventors: Koji SHIMAZAWA, Seiichi TAKAYAMA, Eiji KOMURA, Osamu SHINDO, Takashi HONDA
  • Patent number: 7961438
    Abstract: The invention provides a magnetoresistive device of the CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first shield layer and a second shield layer which are located and formed such that the magnetoresistive unit is sandwiched between them with a sense current applied in a stacking direction. The magnetoresistive unit comprises a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that the nonmagnetic intermediate layer is sandwiched between them. The first shield layer and the second shield layer are each controlled by magnetization direction control means in terms of magnetization direction to create an antiparallel magnetization state where their magnetizations are in opposite directions.
    Type: Grant
    Filed: May 28, 2008
    Date of Patent: June 14, 2011
    Assignee: TDK Corporation
    Inventors: Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya
  • Patent number: 7957085
    Abstract: A thermally assisted magnetic head has a slider substrate having a first surface located on the opposite side to a medium-facing surface, and side surfaces located between the medium-facing surface and the first surface; a magnetic head portion having a waveguide having a light exit face on the medium-facing surface side, and a magnetic recording element disposed in proximity to the light exit face, the magnetic head portion being fixed to one of the side surfaces of the slider substrate; a light source support substrate having a second surface facing the first surface; a light emitting element facing a light entrance face of the waveguide and fixed to the light source support substrate; and an adhesive interposed between the first surface and the second surface; at least one of the first surface and the second surface has a recess and the adhesive is disposed in the recess.
    Type: Grant
    Filed: August 29, 2007
    Date of Patent: June 7, 2011
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Koji Shimazawa, Takaaki Domon
  • Patent number: 7957099
    Abstract: A thermally assisted magnetic head which can realize high-density writing onto magnetic recording media is provided. The thermally assisted magnetic head includes a magnetic head part having a medium-opposing surface and a back face opposing the medium-opposing surface. The magnetic head part has a recording head part, an optical waveguide, and light shields. The optical waveguide extends along the opposing direction of the medium-opposing surface and back face. Each of the light shields extends along the opposing direction of the medium-opposing surface and back face and inhibits laser light from passing between the medium-opposing surface and back face. The optical waveguide and light shields are arranged on a first line when seen from the back face. When seen from the back face, the light shields oppose each other while interposing the first line therebetween and are arranged on a second line substantially orthogonal to the first line.
    Type: Grant
    Filed: July 30, 2008
    Date of Patent: June 7, 2011
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Yasuhiro Ito, Koji Shimazawa
  • Publication number: 20110128827
    Abstract: Provided is a light source unit the weight of which can be reduced while ensuring power supply to the light source. The light source is configured to form a thermally-assisted magnetic recording head by being joined with a slider including an optical system that propagates light for thermal assist. The light source unit comprises: a unit substrate including a joining surface that faces an power-supply electrode of the slider; a first electrode provided on the joining surface; a second electrode provided on a source-installation surface and electrically connected to the first electrode; and a light source that includes two electrode layers and a light-emission center located in a light-emitting surface. The first and second electrodes eliminate the provision of a terminal electrode for light source on the source-integration surface. As a result, the weight of the light source unit can be reduced.
    Type: Application
    Filed: December 1, 2009
    Publication date: June 2, 2011
    Applicant: TDK CORPORATION
    Inventors: Koji SHIMAZAWA, Yasuhiro ITO, Osamu SHINDO, Ryuji FUJII
  • Publication number: 20110122737
    Abstract: A thermally-assisted magnetic recording head is provided, in which the light-source output can be adjusted according to its variation by environmental influences and over time. The head comprises: a light source; a write head element provided in a element-integration surface; an optical system provided in the element-integration surface and configured to guide a light emitted from the light source to the vicinity of one end of the write head element; and a light detector for monitoring the light-source output, provided in the element-integration surface and comprising a light-receiving surface covering an area directly above at least a portion of the optical system. This light detector with such a light-receiving surface can detect a leakage light emitted from the optical system as a monitoring light. Therefore, feedback adjustment of the light-source output can be realized to stabilize the intensity of light for thermal-assist applied to a magnetic recording medium.
    Type: Application
    Filed: November 20, 2009
    Publication date: May 26, 2011
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Seiichi Takayama, Eiji Komura, Osamu Shindo, Takashi Honda
  • Patent number: 7948718
    Abstract: An MR element incorporates: a nonmagnetic conductive layer having two surfaces facing toward opposite directions; a free layer disposed adjacent to one of the surfaces of the nonmagnetic conductive layer, wherein the direction of magnetization in the free layer changes in response to an external magnetic field; and a pinned layer disposed adjacent to the other of the surfaces of the nonmagnetic conductive layer, wherein the direction of magnetization in the pinned layer is fixed to the direction orthogonal to the air bearing surface. The MR element does not include any layer provided for fixing the direction of magnetization in the pinned layer. The pinned layer incorporates a ferromagnetic layer made of a ferromagnetic material having a positive magnetostriction constant. A bottom shield gap film and a top shield gap film disposed adjacent to the MR element each have a compressive stress of 600 MPa or greater.
    Type: Grant
    Filed: March 14, 2005
    Date of Patent: May 24, 2011
    Assignee: TDK Corporation
    Inventors: Takahiko Machita, Koji Shimazawa
  • Patent number: 7948710
    Abstract: In a heat-assisted magnetic recording, a thin-film magnetic head, which can form stable recording bits pattern having steep magnetization transition regions without using a near-field light generating element, is provided. The head is formed on an element forming surface of a substrate, and has a waveguide for leading a light for heat-assist to a magnetic medium and a write element formed on a trailing side of the waveguide and having a magnetic pole for applying a write field to the medium. Here, a write field profile, which is an intensity distribution of the write field from the pole along a track in a recoding layer of the medium, has a projecting region on a leading side. Further, an anisotropy field profile, which is a distribution of an anisotropy field when the anisotropy field is reduced by irradiating the light on a part of the recoding layer, traverses the projecting region.
    Type: Grant
    Filed: July 22, 2008
    Date of Patent: May 24, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Daisuke Miyauchi, Katsuki Kurihara