Patents by Inventor Seiichi Takayama

Seiichi Takayama 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: 20110228653
    Abstract: Provided is a light source unit that is to be joined to a slider to form a thermally-assisted magnetic recording head. The light source unit comprises: a unit substrate having a source-installation surface; a light source provided in the source-installation surface and emitting thermal-assist light; and a photodetector bonded to a rear joining surface of the unit substrate in such a manner that a rear light-emission center of the light source is covered with a light-receiving surface of the photodetector. The photodetector can be sufficiently close to the light source; thus, constant feedback adjustment with high efficiency for the light output of the light source can be performed. This adjustment enables light output from the light source to be controlled in response to changes in light output due to surroundings and to changes with time to stabilize the intensity of light with which a magnetic recording medium is irradiated.
    Type: Application
    Filed: March 22, 2010
    Publication date: September 22, 2011
    Applicants: TDK CORPORATION, HEADWAY TECHNOLOGIES, INC.
    Inventors: Koji SHIMAZAWA, Yoshihiro TSUCHIYA, Seiichi TAKAYAMA, Nobuyuki MORI, Yasuhiro ITO, Kosuke TANAKA, Osamu SHINDO, Ryuji FUJII, Takashi HONDA, Yoshitaka SASAKI
  • Publication number: 20110222184
    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: Application
    Filed: March 9, 2010
    Publication date: September 15, 2011
    Applicant: TDK CORPORATION
    Inventors: Eiji KOMURA, Tsutomu CHOU, Koji SHIMAZAWA, Seiichi TAKAYAMA
  • Patent number: 8009392
    Abstract: Foundation layers of a thin film magnetic head are disposed between insulating layers and bias magnetic field application layers, and are configured of Cr or Cr alloy. The insulating layers are configured of a Si oxide such that the Si content of the Si oxide is in the range of 30˜56 at % (atom %) and that the atom ratio of oxygen to Si (O/Si) is in the range of 0.8˜1.3. With the configuration, the occurrence rate of noise is reduced.
    Type: Grant
    Filed: January 13, 2009
    Date of Patent: August 30, 2011
    Assignee: TDK Corporation
    Inventors: Takayasu Kanaya, Kei Hirata, Yohei Koyanagi, Seiichi Takayama, Shinji Hara, Toshiyuki Ayukawa
  • 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: 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
  • 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
  • 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
  • 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: 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: 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: 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: 7912335
    Abstract: An object of the present invention is to provide a two-dimensional photonic crystal in which conditions for both the TE-polarized light and the TM-polarized light can be easily satisfied. A body includes a first area having a triangular lattice pattern arrangement of a circular hole and a second area having a triangular lattice pattern arrangement of an equilateral triangular holes. Therefore, the TE-PBG which is a photonic band gap (PBG) for the TE-polarized light is created in the first area, and the TM-PBG which is a PBG for the TM-polarized light is created in the second area. Parameters such as the period and size of the holes can be independently set for the first area and the second area, so that an energy region common to the TE-PBG and the TM-PBG (i.e. absolute PBG) can be made larger and easily created.
    Type: Grant
    Filed: December 28, 2005
    Date of Patent: March 22, 2011
    Assignees: Kyoto University, TDK Corporation
    Inventors: Susumu Noda, Takashi Asano, Seiichi Takayama
  • Publication number: 20110058848
    Abstract: An image-forming apparatus includes an image-forming member assembly including a photosensitive member, a developing unit, and a rotating unit; a driving unit; a positioning member having a positioning hole in which a shaft of the photosensitive member is rotatably supported and positioned; and a support member having a support hole that has a guide side to guide a rotating shaft of the rotating unit and supports the rotating shaft in a direction toward and away from the positioning hole. When a force received by the rotating shaft while the driving unit drives the rotating unit is divided into a first component force along the guide side and a second component force orthogonal to the guide side, the first component force has a direction in which a contact force of the shaft of the photosensitive member against an edge of the positioning hole is increased.
    Type: Application
    Filed: May 21, 2010
    Publication date: March 10, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventor: Seiichi TAKAYAMA
  • 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: 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
  • Publication number: 20110002199
    Abstract: Provided is a near-field light generator capable of avoiding a noise to the generated near-field light. The generator comprises a waveguide and a plasmon antenna comprising a propagation surface or edge, for propagating surface plasmon, extending to a near-field light generating end. A portion of one side surface of the waveguide is opposed to a portion of the propagation surface or edge, so as for the waveguide light to be coupled with the plasmon antenna. And an end surface of the waveguide is inclined in such a way as to become away from the plasmon antenna toward the near-field light generating end side. The light that propagates through the waveguide and is not transformed into surface plasmon is refracted or totally reflected in the inclined end surface, does not come close to the generated near-field light, thus does not become a noise for the generated near-field light.
    Type: Application
    Filed: July 1, 2009
    Publication date: January 6, 2011
    Applicant: TDK Corporation
    Inventors: Seiichi Takayama, Daisuke Miyauchi, Susumu Aoki, Koji Shimazawa
  • Patent number: 7855937
    Abstract: Provided is a near-field light generating element capable of avoiding excessive temperature rise, which comprises a waveguide and a near-field light generating layer. The layer comprises: a propagation surface on which surface plasmon excited by the light propagates; and a near-field light generating end at which near-field light is generated. The end is one end of the propagation surface. And a portion of the side surface of the waveguide is opposed to a portion of the propagation surface of the near-field light generating layer with a predetermined spacing so that the light propagating through the waveguide is coupled with the near-field light generating layer in a surface plasmon mode. The near-field light generating layer is preferably tapered toward the near-field light generating end.
    Type: Grant
    Filed: September 5, 2008
    Date of Patent: December 21, 2010
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Eiji Komura, Yasuhiro Ito, Seiichi Takayama, Satoshi Tomikawa, Daisuke Miyauchi, Kosuke Tanaka