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).

  • 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
  • Publication number: 20110116349
    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: a contact-to-waveguide surface having a contact to the waveguide; and a propagation edge provided on the side opposite to the contact-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 is reliably located on the side opposite to the waveguide.
    Type: Application
    Filed: November 13, 2009
    Publication date: May 19, 2011
    Applicant: TDK CORPORATION
    Inventors: Eiji KOMURA, Tsutomu CHOU, Koji SHIMAZAWA
  • Patent number: 7944650
    Abstract: An MR element includes an MR stack including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer disposed between the first and the second ferromagnetic layer. The MR stack has an outer surface, and the spacer layer has a periphery located in the outer surface of the MR stack. The magnetoresistive element further includes a layered film that touches the periphery of the spacer layer. The spacer layer includes a semiconductor layer formed using an oxide semiconductor as a material. The layered film includes a first layer, a second layer, and a third layer stacked in this order. The first layer is formed of the same material as the semiconductor layer, and touches the periphery of the spacer layer. The second layer is a metal layer that forms a Schottky barrier at the interface between the first layer and the second layer. The third layer is an insulating layer.
    Type: Grant
    Filed: September 11, 2007
    Date of Patent: May 17, 2011
    Assignee: TDK Corporation
    Inventors: Yoshihiro Tsuchiya, Koji Shimazawa, Tomohito Mizuno, Shinji Hara, Daisuke Miyauchi, Takahiko Machita
  • Publication number: 20110110202
    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: Application
    Filed: November 12, 2009
    Publication date: May 12, 2011
    Applicant: TDK Corporation
    Inventors: Eiji Komura, Tsutomu Chou, Koji Shimazawa
  • Patent number: 7940486
    Abstract: A laser diode is fixed to a light source support substrate and a first surface of a slider substrate is fixed to a second surface of the light source support substrate; therefore, the slider substrate and the laser diode are kept in a fixed positional relation. Since the laser diode faces a light entrance face of a core, long-distance propagation of light as in the conventional technology does not occur, and light emitted from a light emitting element is guided well to a medium-facing surface while permitting some mounting error and coupling loss of light. A spot size w of a light intensity distribution along the X-axis in the XY plane including an incident-light centroid position on the light entrance face is set larger than a thickness of the core, whereby variation in incidence efficiency is well suppressed against positional deviation.
    Type: Grant
    Filed: August 28, 2007
    Date of Patent: May 10, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Kosuke Tanaka, Takaaki Domon
  • Patent number: 7936531
    Abstract: The thermally assisted magnetic head according to the present invention comprises a medium-facing surface, a main magnetic pole provided on the medium-facing surface, and a plasmon antenna provided on the medium-facing surface, in the vicinity of the main magnetic pole. The shape of the plasmon antenna, as viewed from a direction perpendicular to the medium-facing surface, is a triangle having first, second and third corners, the plasmon antenna being shaped as a flat plate the thickness direction of which is perpendicular to the medium-facing surface. The distance from the first corner to the main magnetic pole is shorter than the distance from the second corner to the main magnetic pole and the distance from the third corner to the main magnetic pole. The second corner and the third corner are rounded.
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: May 3, 2011
    Assignee: TDK Corporation
    Inventors: Satoshi Tomikawa, Seiichi Takayama, Koji Shimazawa
  • Patent number: 7936643
    Abstract: The present thermally assisted magnetic head has: a plasmon antenna; an optical wave guide having the plasmon antenna installed at the tip thereof; a diffraction grating which is disposed in or on the optical wave guide; and a laser element which is disposed at a position to irradiate laser beams onto the diffraction grating, and is composed of a photonic crystal surface emitting semiconductor layer. A laser light intensity distribution on the diffraction grating has at least two intensity peaks in the width direction of the optical wave guide. The two-dimensional form of the laser light intensity distribution on the diffraction grating is a ring or two ellipses.
    Type: Grant
    Filed: February 3, 2009
    Date of Patent: May 3, 2011
    Assignee: TDK Corporation
    Inventors: Seiichi Takayama, Koji Shimazawa
  • Patent number: 7930817
    Abstract: A method comprises an opposing step of arranging a light-shielding film 50 having a recessed surface 52 and a pinhole 54 formed within the recessed surface 52 such that an end face 54X of the pinhole 54 of the light-shielding film 50 on the recessed surface 52 side and a light exit surface 4B oppose each other, while the shortest distance A52 between the light-shielding film 50 and a medium-opposing surface S in a thickness direction of the light-shielding film 50 is shorter than the shortest distance A54 between the end face 54X of the pinhole 54 on the side opposite from a transparent substrate 58 and the light exit surface 4B; a light-emitting step of causing a light-emitting device 3 to emit emission light 3A; and a detecting step of detecting the light transmitted through the pinhole 54 after being emitted from the light exit surface 4B.
    Type: Grant
    Filed: August 27, 2008
    Date of Patent: April 26, 2011
    Assignee: TDK Corporation
    Inventors: Seiichi Takayama, Koji Shimazawa, Yasuhiro Ito
  • Publication number: 20110090587
    Abstract: A thermally-assisted magnetic recording head includes a surface-emitting type light source for emitting substantially collimated beam, a first diffraction optical element for focusing the substantially collimated beam emitted from the surface-emitting type light source, a second diffraction optical element for collimating the light beam focused by the first diffraction optical element, a waveguide integrally formed with the second diffraction optical element and made of the material as that of second diffraction optical element, the light beam collimated by the second diffraction optical element being incident to the waveguide, an optical-path direction conversion element for converting a direction of an optical path of the incident light beam to a propagation direction of the waveguide, the propagation direction being toward an opposed-to-medium surface, and a magnetic pole for generating write field from its end face on the opposed-to-medium surface side.
    Type: Application
    Filed: October 19, 2009
    Publication date: April 21, 2011
    Applicant: TDK Corporation
    Inventors: Tsutomu Chou, Eiji Komura, Koji Shimazawa, Seiichi Takayama
  • Patent number: 7924658
    Abstract: Provided is a method for manufacturing a heat-assisted magnetic recording head, capable of joining a light source unit and a slider with a sufficiently high alignment accuracy. In the method, the unit including a light source is joined to the slider including a head part. First, at least one marker provided on the head-part end surface is set so that the distance from the waveguide incident center to the marker end is substantially equal to the distance from the light-emission center of the light source to the end surface of the light source. After that, the unit and slider are relatively moved while keeping the unit in surface contact with the slider, and the relative positions are set so that the end of the marker coincides with, or is at a distance within an acceptable range from, the edge of the surface of the light source.
    Type: Grant
    Filed: October 6, 2008
    Date of Patent: April 12, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Yasuhiro Ito
  • Patent number: 7920362
    Abstract: A giant magneto-resistive effect device having a CPP structure including a spacer layer, and a fixed magnetization layer and a free layer stacked one upon another with said spacer layer interposed between them. The free layer functions such that its magnetization direction changes depending on an external magnetic field. The spacer layer comprises a first nonmagnetic metal layer and a second nonmagnetic metal layer, each formed of a nonmagnetic metal material. A semiconductor oxide layer is interposed between them. The semiconductor oxide layer forming a part of the spacer layer comprises zinc oxide as a main ingredient.
    Type: Grant
    Filed: November 20, 2007
    Date of Patent: April 5, 2011
    Assignee: TDK Corporation
    Inventors: Shinji Hara, Kei Hirata, Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno
  • Patent number: 7911882
    Abstract: A thin-film magnetic head that has a configuration in which the element-formed surface and the opposed-to-medium surface are perpendicular to each other, and a light source is sufficiently distanced from the medium surface is provided. The head comprises at least one near-field-light-generating layer for heating a part of a magnetic medium during write operation by generating a near-field light, having a shape tapered toward a head end surface on the opposed-to-medium surface side, and comprising a near-field-light-generating portion having a light-received surface and a tip reaching the head end surface on the opposed-to-medium surface side, and the light-received surface being sloped in respect to the element-formed surface and being provided in a position where an incident light propagating from a head end surface opposite to the opposed-to-medium surface can reach at least a part of the light-received surface.
    Type: Grant
    Filed: November 27, 2006
    Date of Patent: March 22, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Katsumichi Tagami
  • Patent number: 7895731
    Abstract: A method for manufacturing a magnetic field detecting element having a free layer whose magnetization direction is variable depending on an external magnetic field and a pinned layer whose magnetization direction is fixed and these are stacked with an electrically conductive, nonmagnetic spacer layer sandwiched therebetween, wherein sense current flows in a direction perpendicular to film planes of the magnetic field detecting element. The method comprises: forming a spacer adjoining layer adjacent to the spacer layer, Heusler alloy layer, and a metal layer successively in this order; and forming either at least a part of the pinned layer or the free layer by heating the spacer adjoining layer, the Heusler alloy layer, and the metal layer. The spacer adjoining layer has a layer chiefly made of cobalt and iron. The Heusler alloy layer includes metal which is silver, gold, copper, palladium, or platinum, or an alloy thereof. The metal layer is made of the same.
    Type: Grant
    Filed: June 22, 2007
    Date of Patent: March 1, 2011
    Assignee: TDK Corporation
    Inventors: Tomohito Mizuno, Yoshihiro Tsuchiya, Koji Shimazawa, Kei Hirata, Keita Kawamori
  • Patent number: 7898909
    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, a second surface opposite the first surface, and a third surface opposite the medium-facing surface. The magnetic head portion comprises a main magnetic pole, an optical waveguide core having a first light exit surface at the medium-facing surface and a second light exit surface at the third surface, a first diffraction grating, provided in the optical waveguide core or further towards the second surface than the optical waveguide core, and a light reflective section provided further toward the first surface than the optical waveguide core.
    Type: Grant
    Filed: February 12, 2009
    Date of Patent: March 1, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Yasuhiro Ito, Seiichi Takayama
  • Patent number: 7894165
    Abstract: The invention provides a magneto-resistive effect device having a CPP (current perpendicular to plane) structure comprising a nonmagnetic spacer layer, and a fixed magnetized layer and a free layer stacked one upon another with said nonmagnetic spacer layer sandwiched between them, with a sense current applied in a stacking direction, wherein said free layer functions such that its magnetization direction changes depending on an external magnetic field, and is made up of a multilayer structure including a Heusler alloy layer, wherein an Fe layer is formed on one of both planes of said Heusler alloy layer in the stacking direction, wherein said one plane is near to at least a nonmagnetic spacer layer side, and said fixed magnetization layer is made up of a multilayer structure including a Heusler alloy layer, wherein Fe layers are formed on both plane sides of said Heusler alloy layer in the stacking direction with said Heusler alloy layer sandwiched between them.
    Type: Grant
    Filed: June 13, 2007
    Date of Patent: February 22, 2011
    Assignee: TDK Corporation
    Inventors: Tomohito Mizuno, Yoshihiro Tsuchiya, Koji Shimazawa
  • Publication number: 20110038236
    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: Application
    Filed: August 13, 2009
    Publication date: February 17, 2011
    Applicant: TDK Corporation
    Inventors: Tomohito Mizuno, Yoshihiro Tsuchiya, Koji Shimazawa, Tsutomu Chou
  • Patent number: 7885042
    Abstract: A giant magneto-resistive effect device having a CPP structure comprising a spacer layer, and a fixed magnetization layer and a free layer stacked one upon another with the spacer layer interposed between them, with a sense current applied in a stacking direction. The spacer layer comprises a first nonmagnetic metal layer and a second nonmagnetic metal layer, each made of a nonmagnetic metal material, and a semiconductor layer formed between the first and the second nonmagnetic metal layer. The semiconductor layer is an n-type oxide semiconductor. When the first and second nonmagnetic metal layers are formed in order, the first nonmagnetic metal layer is formed prior to the second nonmagnetic metal layer, and an anti-oxidizing layer is formed between the first nonmagnetic metal layer and the semiconductor layer. The anti-oxidizing layer is formed of a material incapable of producing a Schottky barrier upon joining to the semiconductor layer.
    Type: Grant
    Filed: October 10, 2007
    Date of Patent: February 8, 2011
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Kei Hirata
  • Patent number: 7885029
    Abstract: A head capable of favorite thermally-assisted magnetic recording without depending on the use of a near-field light generator is provided. The head comprises a write head element formed on the trailing side from a waveguide and comprising a first main pole. The first main pole and the waveguide are opposed to each other through a first clad layer, and a second clad layer is provided on a rear side from the first main pole. This gives that the end surface of the waveguide can be placed much close to the end surface of the first main pole apart by only a thickness of the first clad layer. As a result, the end surface of the first main pole can apply a sufficient intensity of write field to the intensity center and its vicinity of the light spot formed on the magnetic recording layer.
    Type: Grant
    Filed: April 14, 2009
    Date of Patent: February 8, 2011
    Assignee: TDK Corporation
    Inventors: Daisuke Miyauchi, Susumu Aoki, Seiichi Takayama, Koji Shimazawa, Tetsuya Roppongi
  • Publication number: 20110026377
    Abstract: A thermally-assisted magnetic recording head is provided, in which a light source having sufficiently high output power for performing thermal-assist is disposed in the element-integration surface of the substrate to achieve improved mass-productivity. The head includes: a light source having a multilayered structure including a photonic-band layer and having a light-emitting surface opposed to the element-integration surface; a diffraction optical element that converges the emitted light; a light-path changer that changes the direction of the converged light; a waveguide that propagates the direction-changed light toward the opposed-to-medium surface; and a magnetic pole that generates write field. The surface-emitting type light source includes a photonic-band layer having a periodic structure in which a light from an active region resonates, and thus emits laser light on a quite different principle from a VCSEL.
    Type: Application
    Filed: July 30, 2009
    Publication date: February 3, 2011
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Seiichi Takayama, Tsutomu Chou, Eiji Komura
  • Publication number: 20110026379
    Abstract: A heat-assisted magnetic recording head includes a slider, and an edge-emitting laser diode fixed to the slider. The slider has a waveguide and an overcoat layer that covers the waveguide. The laser diode has an emitting end face including an emission part for emitting laser light, and a bottom surface. The laser diode is arranged so that the bottom surface faces the top surface of the slider. The waveguide has an incident end face opposed to the emission part of the laser diode. The overcoat layer has an end face that faces the emitting end face of the laser diode. As viewed from above, the end face of the overcoat layer has a convex shape protruding toward the emitting end face of the laser diode so that a part of the end face of the overcoat layer lying over the incident end face of the waveguide comes closest to the emitting end face of the laser diode.
    Type: Application
    Filed: July 28, 2009
    Publication date: February 3, 2011
    Applicant: TDK CORPORATION
    Inventors: Koji Shimazawa, Seiichi Takayama, Yasuhiro Ito, Daisuke Miyauchi, Kosuke Tanaka