Patents by Inventor Tsutomu Chou

Tsutomu Chou 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: 8189303
    Abstract: A thin film magnetic head includes a magneto-resistance (MR) laminated body, a lower shield layer and an upper shield layer that face the first MR magnetic layer. The lower and upper shield layers respectively have first and second anti-parallel layers and first and second antiferromagnetic layers. An exchange coupling intensity relating to an antiferromagnetic coupling between the second anti-parallel layer and the second antiferromagnetic layer is greater in the peripheral area of a projection area than that of the projection area of the upper shield layer side end surface of the MR laminated body to the film surface's orthogonal direction.
    Type: Grant
    Filed: August 12, 2008
    Date of Patent: May 29, 2012
    Assignee: TDK Corporation
    Inventors: Shinji Hara, Yoshihiro Tsuchiya, Tsutomu Chou, Daisuke Miyauchi, Takahiko Machita
  • Publication number: 20120127838
    Abstract: A thermally assisted magnetic recording head includes a magnetic recording element part for writing, a main waveguide for assistance for receiving light, and a dummy waveguide component part provided in parallel to the main waveguide. The dummy waveguide component part includes a pair of waveguides having the same shape and dimensions including a first waveguide and a second waveguide that receive light from a back end surface opposite to an air bearing surface and guides the light toward the air bearing surface, and light emitting ends of the first waveguide and the second waveguide facing towards the air bearing surface have no shielding material, and are in a free condition so that the light intensity from the light emitting ends can be measured.
    Type: Application
    Filed: November 22, 2010
    Publication date: May 24, 2012
    Applicant: TDK CORPORATION
    Inventors: Eiji Komura, Tsutomu Chou
  • Publication number: 20120120781
    Abstract: Provided is a surface plasmon resonating optical system emitting near-field light (NF-light) with a higher light density. The system comprises: a waveguide through which a light for exciting surface plasmon propagates; a plasmon generator that couples with the light in a surface plasmon mode and emits NF-light from its NF-light generating end surface; and a resonator mirror that reflects the excited surface plasmon, provided on the side of the plasmon generator opposite to the NF-light generating end surface. In the system, the excited surface plasmon can be amplified by using a resonator structure while reducing the length of the plasmon generator to reduce absorption of surface plasmon and prevent overheating of the plasmon generator.
    Type: Application
    Filed: November 15, 2010
    Publication date: May 17, 2012
    Applicant: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa
  • Publication number: 20120117791
    Abstract: In a method for manufacturing a thermally-assisted magnetic head that includes a slider and an LD unit, the slider including an air bearing surface (ABS) that faces a recording medium and including a waveguide with a core for light propagation that extends from a light entering surface, which is different from the ABS, to the ABS, the LD unit being attached to the light entering surface of the slider, and the thermally-assisted magnetic head performing magnetic recording while heating the recording medium with near-field light that is excited from linearly polarized laser light, the LD unit is disposed in a position facing the light entering surface of the slider, a photo detector is disposed in a position facing the ABS of the slider, and a polarizer transmitting only light having a polarization component that is orthogonal to a polarization direction of the linearly polarized laser light is disposed between the ABS and the photo detector.
    Type: Application
    Filed: November 16, 2010
    Publication date: May 17, 2012
    Applicant: TDK Corporation
    Inventors: Shinji HARA, Koji Shimazawa, Eiji Komura, Tsutomu Chou, Seiichi Takayama
  • Publication number: 20120120780
    Abstract: Provided is a thermally-assisted magnetic recording head in which NF-light with sufficiently high light density can be applied to a medium while a write-field generating point and a near-field light (NF-light) generating point are close to each other. The head comprises a plasmon generator provided between a magnetic pole and a waveguide and configured to be coupled with light propagating through the waveguide in a surface plasmon mode to emit NF-light. The plasmon generator comprises: a plasmon propagating part comprising a propagation edge for propagating surface plasmon excited by the light; and a light penetration suppressing part with an extinction coefficient greater than the plasmon propagating part. The light penetration suppressing part is in surface-contact with a surface portion of the plasmon propagating part excluding the propagation edge, and the magnetic pole is in surface-contact with the light penetration suppressing part.
    Type: Application
    Filed: November 15, 2010
    Publication date: May 17, 2012
    Applicant: TDK CORPORATION
    Inventors: EIJI KOMURA, TSUTOMU CHOU, KOJI SHIMAZAWA
  • Patent number: 8169861
    Abstract: Provided is a thermally-assisted magnetic recording head in which NF-light with sufficiently high light density can be applied to a medium while a write-field generating point and a near-field light (NF-light) generating point are close to each other. The head comprises a plasmon generator provided between a magnetic pole and a waveguide and configured to be coupled with light propagating through the waveguide in a surface plasmon mode to emit NF-light. The plasmon generator comprises: a plasmon propagating part comprising a propagation edge for propagating surface plasmon excited by the light; and a light penetration suppressing part with an extinction coefficient greater than the plasmon propagating part. The light penetration suppressing part is in surface-contact with a surface portion of the plasmon propagating part excluding the propagation edge, and the magnetic pole is in surface-contact with the light penetration suppressing part.
    Type: Grant
    Filed: November 15, 2010
    Date of Patent: May 1, 2012
    Assignee: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa
  • Patent number: 8169731
    Abstract: Provided is a near-field light transducer with a propagation edge in which the generation of defects is suppressed. The transducer is formed of a Ag alloy and comprises an edge, the edge comprising a portion to be coupled with a light in a surface plasmon mode, the edge extending from the portion to a near-field light generating end surface, and the edge being configured to propagate surface plasmon excited by the light. Further, a curvature radius of the rounded edge is set in the range from 6.25 nm to 20 nm. In the edge and its vicinity, the generation of defects such as cracking and chipping is suppressed. Thereby improved are a propagation efficiency of surface plasmon and a light use efficiency of the transducer. The Ag alloy preferably contains at least one element selected from a group of Pd, Au, Cu, Ru, Rh and Ir.
    Type: Grant
    Filed: August 13, 2009
    Date of Patent: May 1, 2012
    Assignee: TDK Corporation
    Inventors: Tomohito Mizuno, Yoshihiro Tsuchiya, Koji Shimazawa, Tsutomu Chou
  • Patent number: 8170389
    Abstract: An optical waveguide includes a core and a clad. The core includes first to third propagation parts, and a coupling part that couples the first to third propagation parts together. The first propagation part has a first incidence end face on which part of incident light is incident, and a first emission part that emits first propagation light. The second propagation part has a second incidence end face on which another part of the incident light is incident, and a second emission part that emits second propagation light. In the coupling part, a first light wave resulting from the first propagation light and a second light wave resulting from the second propagation light occur, and the first and second light waves interfere with each other to generate third propagation light to be emitted from a third emission part. The third propagation part propagates the third propagation light.
    Type: Grant
    Filed: January 28, 2011
    Date of Patent: May 1, 2012
    Assignee: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou
  • Publication number: 20120084969
    Abstract: A method of manufacturing a thermally-assisted magnetic write head is provided. The method includes steps of: forming a laminate structure including the waveguide; the plasmon generator, and the magnetic pole in order; performing a first polishing process to planarize an end surface of the laminate structure; performing a first etching process to remove impurity attached on the end surface of the laminate structure, and to allow the plasmon generator to be recessed from the waveguide and the magnetic pole, thereby forming a recessed region on the end surface of the laminate structure; forming a protection layer on the end surface of the laminate structure such that at least the recessed region is filled; and performing a second polishing process on the end surface of the laminate structure formed with the protection layer until the plasmon generator is exposed, thereby completing the air bearing surface.
    Type: Application
    Filed: October 12, 2010
    Publication date: April 12, 2012
    Applicants: SAE MAGNETICS (H.K.) LTD., TDK CORPORATION
    Inventors: Kosuke TANAKA, Shinji HARA, Tsutomu CHOU, Yasutoshi FUJITA
  • Publication number: 20120082016
    Abstract: An optical waveguide of the invention includes a core that is a waveguide through which light propagates; and a cladding that surrounds the core. The core has a plate shape and includes a wide core base part onto which the light is incident, a taper part that is connected to the core base part and of which a width is gradually tapered along a propagation direction, and a narrow front end core part that is connected to the taper part and that extends along the propagation direction.
    Type: Application
    Filed: October 5, 2010
    Publication date: April 5, 2012
    Applicant: TDK CORPORATION
    Inventors: Eiji Komura, Tsutomu Chou
  • Patent number: 8147994
    Abstract: A layered structure includes an amorphous Ta layer, a metallic oxide layer formed from zinc oxide (ZnO) or magnesium oxide (MgO) on the Ta layer, and a FePt magnetic layer formed on the metallic oxide layer. Therefore, an L10 structural FePt ordered alloy is obtained at a temperature of 300° C. or lower.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: April 3, 2012
    Assignee: TDK Corporation
    Inventors: Hironobu Matsuzawa, Tsutomu Chou
  • Publication number: 20120075967
    Abstract: A thermally assisted magnetic head includes a magnetic pole that generates a writing magnetic field from an air bearing surface (ABS); a waveguide through which light propagates; and a plasmon generator generating near-field light from a near-field light generating end surface by coupling the light thereto in a surface plasmon mode. The magnetic pole includes a convex part protruding in a substantially V-shape along a light propagation direction of the waveguide. The plasmon generator includes a substantially V-shaped part contacting the convex part, and as seen from a side of the ABS, a thickness of the plasmon generator in a direction perpendicular to convex part contacting sides gradually increases from an end in a direction away from the waveguide, the convex part contacting sides being linear sides that form the substantially V-shaped part of the plasmon generator and contacting the convex part.
    Type: Application
    Filed: September 28, 2010
    Publication date: March 29, 2012
    Applicant: TDK CORPORATION
    Inventors: Tsutomu Chou, Eiji Komura, Shinji Hara, Kosuke Tanaka, Daisuke Miyauchi
  • Patent number: 8130599
    Abstract: There is provided a near-field-light (NFL) generating optical system in which the point where near-field (NF) light is generated can be provided sufficiently close to the end surface of a magnetic pole that generates write field. The optical system comprises: a waveguide through which a light for exciting surface plasmon propagates; and a NF-optical device configured to be coupled with the light in a surface plasmon mode. The NF-optical device comprises: an opposed-to-waveguide surface opposed to the waveguide with a predetermined distance; and a propagation edge provided on the side opposite to the opposed-to-waveguide surface, extending to the NFL-generating end surface of the device, and configured to propagate thereon the surface plasmon excited by the light. In this optical system, the point, where NF-light is generated, of the NFL-generating end surface can be located on the side opposite to the waveguide.
    Type: Grant
    Filed: November 12, 2009
    Date of Patent: March 6, 2012
    Assignee: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa
  • Patent number: 8125858
    Abstract: A plasmon generator has an outer surface including a plasmon exciting part, and has a near-field light generating part located in a medium facing surface. The plasmon exciting part faces an evanescent light generating surface of a waveguide's core with a predetermined distance therebetween. The outer surface of the plasmon generator further includes first and second inclined surfaces that are each connected to the plasmon exciting part. The first and second inclined surfaces increase in distance from each other with increasing distance from the plasmon exciting part. The plasmon generator includes a shape changing portion where the angle of inclination of each of the first and second inclined surfaces with respect to the evanescent light generating surface increases continuously with decreasing distance to the medium facing surface.
    Type: Grant
    Filed: March 22, 2010
    Date of Patent: February 28, 2012
    Assignee: TDK Corporation
    Inventors: Shinji Hara, Tsutomu Chou, Kosuke Tanaka, Eiji Komura, Koji Shimazawa, Daisuke Miyauchi, Susumu Aoki, Takeshi Tsutsumi
  • Patent number: 8125857
    Abstract: A plasmon generator has an outer surface including a propagation edge, and has a near-field light generating part lying at an end of the propagation edge and located in a medium facing surface. The propagation edge faces an evanescent light generating surface of a waveguide's core with a predetermined distance therebetween and extends in a direction perpendicular to the medium facing surface. The propagation edge is arc-shaped in a cross section parallel to the medium facing surface. The plasmon generator includes a shape changing portion in which a radius of curvature of the propagation edge in the cross section parallel to the medium facing surface continuously decreases with decreasing distance to the medium facing surface.
    Type: Grant
    Filed: March 22, 2010
    Date of Patent: February 28, 2012
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Daisuke Miyauchi, Susumu Aoki, Tetsuya Roppongi, Tsutomu Chou, Shinji Hara, Eiji Komura
  • Patent number: 8116175
    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: Grant
    Filed: March 8, 2010
    Date of Patent: February 14, 2012
    Assignee: TDK Corporation
    Inventors: Tsutomu Chou, Eiji Komura, Koji Shimazawa, Shinji Hara
  • Publication number: 20120026846
    Abstract: Provided is a thermally-assisted magnetic recording head with improved light density of near-field light (NF-light) with which a medium is irradiated. The head comprises: a magnetic pole; a waveguide for propagating light for exciting surface plasmon; a surface plasmon generator provided between the magnetic pole and the waveguide, coupled with the light in a surface plasmon mode, and emitting NF-light; and a clad portion provided at least between the waveguide and the surface plasmon generator and comprising a transition region in which a refractive index decreases along a direction from the waveguide toward the magnetic pole. The provision of the clad portion including the transition region enables improvement of the light density of NF-light due to the convergence of surface plasmon excited in the surface plasmon generator to predetermined locations, while avoiding the problem of temperature rise due to reduction of the volume of surface plasmon generator.
    Type: Application
    Filed: August 2, 2010
    Publication date: February 2, 2012
    Applicant: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa
  • Publication number: 20120014230
    Abstract: A magnetic recording element that faces a recording medium and that executes a magnetic recording while the recording medium is heated, the element including a waveguide that is configured with a core and a cladding, the core, through which laser light propagates, including an enlarged part, which is enlarged at an air bearing surface facing the recording medium; and the cladding surrounding a periphery of the core.
    Type: Application
    Filed: July 16, 2010
    Publication date: January 19, 2012
    Applicant: TDK Corporation
    Inventors: Shinji HARA, Tsutomu Chou, Tetsuya Roppongi, Daisuke Miyauchi, Kosuke Tanaka
  • Patent number: 8098547
    Abstract: An optical waveguide, on account of its ability to apply phase resonance of a wavelength and of a first and second triangular plate-like spot size converter members formed of the same material as a core material and being arranged and formed in a substantially symmetrical structure, can promote shortening of the waveguide length and contrive to reduce the size of the optical waveguide itself. Further, an optical waveguide having excellent spot size conversion efficiency can be obtained even in a reduced size.
    Type: Grant
    Filed: March 9, 2010
    Date of Patent: January 17, 2012
    Assignee: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa, Seiichi Takayama
  • Patent number: 8094420
    Abstract: The invention provides a magnetoresistive device of the CCP (current perpendicular to plane) structure comprising a magnetoresistive unit sandwiched between soft magnetic shield layers with a current applied in the stacking direction. The magnetoresistive unit comprises a nonmagnetic intermediate layer sandwiched between ferromagnetic layers. A planar framework positions the soft magnetic shield layers and comprises a combination of a nonmagnetic gap layer with a bias magnetic field-applying layer constructed by repeating the stacking of a multilayer unit comprising a nonmagnetic underlay layer and a high coercive material layer. The nonmagnetic gap layer is designed and located such that a magnetic flux given out of the bias magnetic field-applying layer is efficiently directed along a closed magnetic path around the framework to form a single domain of magnetization.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: January 10, 2012
    Assignee: TDK Corporation
    Inventors: Toshiyuki Ayukawa, Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Koji Shimazawa, Shinji Hara, Tomohito Mizuno, Yoshihiro Tsuchiya