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).
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Publication number: 20110026379Abstract: 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: ApplicationFiled: July 28, 2009Publication date: February 3, 2011Applicant: TDK CORPORATIONInventors: Koji Shimazawa, Seiichi Takayama, Yasuhiro Ito, Daisuke Miyauchi, Kosuke Tanaka
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Publication number: 20110026156Abstract: A heat-assisted magnetic recording head includes a slider, and an edge-emitting laser diode that emits polarized light of TM mode. The laser diode is arranged so that its bottom surface faces the top surface of the slider. An electrode of the laser diode closer to the active layer is bonded to a conductive layer of the slider, whereby the laser diode is fixed to the slider. As viewed from above the laser diode, the bottom surface of the electrode of the laser diode includes a first area that a light propagation path of the laser diode overlies, and a second area other than the first area. The top surface of the conductive layer is in contact not with the first area but with the second area of the bottom surface of the electrode.Type: ApplicationFiled: August 3, 2009Publication date: February 3, 2011Applicant: TDK CORPORATIONInventors: Koji Shimazawa, Yasuhiro Ito, Yuji Kakinuma, Daisuke Miyauchi, Kosuke Tanaka
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Publication number: 20110026378Abstract: A heat-assisted magnetic recording head includes a slider, and an edge-emitting laser diode fixed to the slider. The slider includes: a substrate; and an MR element, two reproduction wiring layers, a coil, two recording wiring layers, a magnetic pole, a near-field light generating element, and a waveguide that are stacked above the top surface of the substrate. The two reproduction wiring layers supply a sense current to the MR element. The two recording wiring layers supply a coil current to the coil. 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. As viewed from above, the laser diode does not overlap the two reproduction wiring layers but overlaps at least one of the two recording wiring layers.Type: ApplicationFiled: July 28, 2009Publication date: February 3, 2011Applicant: TDK CORPORATIONInventors: Koji Shimazawa, Tomohito Mizuno, Eiji Komura
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Patent number: 7881023Abstract: The invention provides a magnetoresistive device with the CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first shield layer and a second shield layer located and formed such that the magnetoresistive unit is sandwiched between them, with a sense current applied in a stacking direction, wherein 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 interposed between them, wherein the first shield layer, and the second shield layer is controlled by magnetization direction control means in terms of magnetization direction, and the first ferromagnetic layer, and the second ferromagnetic layer receives action such that there is an antiparallel magnetization state created, in which mutual magnetizations are in opposite directions, under the influences of magnetic actions of the first shield layer and the second shield layer.Type: GrantFiled: January 24, 2008Date of Patent: February 1, 2011Assignee: TDK CorporationInventors: Takahiko Machita, Koji Shimazawa, Daisuke Miyauchi, Tsutomu Chou
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Patent number: 7881025Abstract: The invention provides a CPP-GMR device comprising a spacer layer. The spacer layer comprises a first nonmagnetic metal layer and a second nonmagnetic metal layer, each formed of a nonmagnetic metal material, and a semiconductor layer interposed between the first nonmagnetic metal layer and the second nonmagnetic metal layer, and further comprises a work function control layer formed between the first nonmagnetic metal layer and the semiconductor layer and/or between the second nonmagnetic metal layer and the semiconductor layer. The semiconductor layer is an n-type semiconductor, and the work function control layer is made of a material having a work function smaller than that of said first nonmagnetic metal layer, and said second nonmagnetic metal layer. It is thus possible to obtain by far more improved advantages.Type: GrantFiled: October 31, 2007Date of Patent: February 1, 2011Assignee: TDK CorporationInventors: Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Kei Hirata
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Patent number: 7881021Abstract: A magnetoresistive device with CPP structure, comprising a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed with said nonmagnetic intermediate layer interposed between them, wherein each of said first and second ferromagnetic layers comprises a sensor area joining to the nonmagnetic intermediate layer and a magnetization direction control area that extends further rearward from the position of the rear end of said nonmagnetic intermediate layer; a magnetization direction control multilayer arrangement is interposed at an area where the magnetization direction control area for said first ferromagnetic layer is opposite to the magnetization direction control area for said second ferromagnetic layer to produce magnetizations of the said first and second ferromagnetic layers which are antiparallel with each other; and said sensor area is provided at both width direction ends with biasing layers working such that the mutually antiparallel magnetizaType: GrantFiled: January 30, 2008Date of Patent: February 1, 2011Assignee: TDK CorporationInventors: Tsutomu Chou, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tomohito Mizuno, Hironobu Matsuzawa, Toshiyuki Ayukawa, Koji Shimazawa, Kiyoshi Noguchi
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Patent number: 7876535Abstract: A magnetoresistive device of a CPP (current perpendicular to plane) structure includes a magnetoresistive unit sandwiched between a first substantially soft magnetic shield layer from below, and a second substantially soft magnetic shield layer from above, with a sense current applied in a stacking direction. The magnetoresistive unit includes a non-magnetic intermediate layer sandwiched between a first ferromagnetic layer, and a second ferromagnetic layer. At least one of the first and second shield layers is configured in a window frame of a planar shape, including a front frame-constituting portion and a back frame-constituting portion partially comprising a combination of a nonmagnetic gap layer with a bias magnetic field-applying layer. The combination of the nonmagnetic gap layer with the bias magnetic field-applying layer forms a closed magnetic path with magnetic flux going all the way around the window framework, turning the magnetization of the front frame-constituting portion into a single domain.Type: GrantFiled: January 24, 2008Date of Patent: January 25, 2011Assignee: TDK CorporationInventors: Takahiko Machita, Koji Shimazawa, Daisuke Miyauchi, Tsutomu Chou
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Patent number: 7876646Abstract: A thermally assisted magnetic head comprises: a slider substrate, a first surface located opposite to a medium-facing surface, and side surfaces located between the medium-facing surface and the first surface; a magnetic head portion having a near-field light generator on the medium-facing surface side, and a magnetic recording element, the magnetic head portion being fixed to one of the side surfaces; and a laser diode element a relative position of which to the slider substrate is fixed so that emitted light thereof can reach the near-field light generator; a relation of ?in<?max is satisfied, where ?in is a wavelength of the emitted light from the laser diode element immediately before the emitted light reaches the near-field light generator, and ?max is a wavelength of irradiating light at which an efficiency of generation of near-field light generated from the near-field light generator is maximum.Type: GrantFiled: December 26, 2007Date of Patent: January 25, 2011Assignee: TDK CorporationInventors: Kosuke Tanaka, Koji Shimazawa, Eiji Komura
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Patent number: 7868628Abstract: 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: GrantFiled: August 16, 2007Date of Patent: January 11, 2011Assignee: TDK CorporationInventor: Koji Shimazawa
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Publication number: 20110002199Abstract: 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: ApplicationFiled: July 1, 2009Publication date: January 6, 2011Applicant: TDK CorporationInventors: Seiichi Takayama, Daisuke Miyauchi, Susumu Aoki, Koji Shimazawa
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Patent number: 7855859Abstract: In an MR element, first and second ferromagnetic layers are antiferromagnetically coupled to each other through a spacer layer, and have magnetizations that are in opposite directions when no external magnetic field is applied thereto and that change directions in response to an external magnetic field. The spacer layer and the second ferromagnetic layer are stacked in this order on the first ferromagnetic layer. The first ferromagnetic layer includes a plurality of ferromagnetic material layers stacked, and an insertion layer made of a nonmagnetic material and inserted between respective two of the ferromagnetic material layers that are adjacent to each other along the direction in which the layers are stacked. The ferromagnetic material layers and the spacer layer each include a component whose crystal structure is a face-centered cubic structure.Type: GrantFiled: December 27, 2007Date of Patent: December 21, 2010Assignee: TDK CorporationInventors: Shinji Hara, Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Tsuyoshi Ichiki, Toshiyuki Ayukawa
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Patent number: 7855937Abstract: 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: GrantFiled: September 5, 2008Date of Patent: December 21, 2010Assignee: TDK CorporationInventors: Koji Shimazawa, Eiji Komura, Yasuhiro Ito, Seiichi Takayama, Satoshi Tomikawa, Daisuke Miyauchi, Kosuke Tanaka
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Publication number: 20100315736Abstract: A waveguide is provided, in which the optical coupling efficiency to a light source is sufficiently high, and the light-emitting spot center is stably provided at the intended position. The waveguide comprises a multilayered structure in which refractive indexes of layers having a surface contact with each other are different from each other. The multilayered structure is divided into a plurality of groups, and the length from the light-receiving end surface to the light-emitting end surface of one group is different from that of the neighboring group, and the protruded light-emitting end surface of the first group defined as a group that has the largest length includes a center of the light-emitting spot. In this waveguide, the state in which the light-emitting spot center is positioned within the light-emitting end surface does not easily be changed, even when the light-receiving spot center within the light-receiving end surface is rather displaced.Type: ApplicationFiled: June 11, 2009Publication date: December 16, 2010Applicant: TDK CorporationInventors: Seiichi Takayama, Satoshi Tomikawa, Toshiyuki Ayukawa, Daisuke Miyauchi, Koji Shimazawa
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Publication number: 20100302672Abstract: A magnetic recording head capable of a satisfying thermally-assisted magnetic recording without depending on the use of a near-field light generator is provided. The head comprises a waveguide and a main magnetic pole having a main pole tip. Further, at least a portion of the main pole tip is embedded in a groove provided in the upper surface of the waveguide. Further, a second clad layer is provided on the first clad layer and on a rear side from the main pole tip. This configuration of the first and second clad layers suppresses the absorption of the light propagating through the waveguide by the main magnetic pole. Further, the configuration in which at least a portion of the main pole tip is embedded in the groove can cause the distance between the light spot center of the waveguide and the main magnetic pole to be sufficiently small.Type: ApplicationFiled: May 26, 2009Publication date: December 2, 2010Applicant: TDK CORPORATIONInventors: Susumu AOKI, Daisuke MIYAUCHI, Seiichi TAKAYAMA, Koji SHIMAZAWA, Tetsuya ROPPONGI
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Patent number: 7843668Abstract: A magnetoresistive element includes a first and a second shield, and an MR stack disposed between the shields. The MR stack includes a first and a second ferromagnetic layer, and a nonmagnetic spacer layer disposed between the ferromagnetic layers. The first and second ferromagnetic layers have magnetizations that are in directions antiparallel to each other when no external magnetic field is applied to the layers, and that change directions in response to an external magnetic field. An insulating layer is formed to touch a rear end face of the MR stack and the first shield, and a bias magnetic field applying layer is formed above the insulating layer with a buffer layer disposed in between. The bias magnetic field applying layer includes a hard magnetic layer and a high saturation magnetization layer. The high saturation magnetization layer is located between the rear end face and the hard magnetic layer, but not located between the first shield and the hard magnetic layer.Type: GrantFiled: December 27, 2007Date of Patent: November 30, 2010Assignee: TDK CorporationInventors: Takahiko Machita, Kei Hirata, Koji Shimazawa, Daisuke Miyauchi
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Patent number: 7835102Abstract: Provided is a plasmon antenna in which a near-field light having a sufficient intensity is generated only in a desired location. The plasmon antenna comprises an end surface on a side where a near-field light is generated; the end surface is flat and has a shape with at least three vertexes or rounded corners; and an end surface of the plasmon antenna which is opposite to the flat end surface and receives light, is inclined with respect to the flat end surface so as to become closer to the flat end surface toward one of the at least three vertexes or rounded corners. When the light-receiving end surface of the plasmon antenna is irradiated with the light, a near-field light having a sufficient intensity can be generated at only the vertex or rounded corner toward which the entire plasmon antenna becomes thinner.Type: GrantFiled: September 26, 2008Date of Patent: November 16, 2010Assignee: TDK CorporationInventors: Seiichi Takayama, Eiji Komura, Kosuke Tanaka, Daisuke Miyauchi, Koji Shimazawa
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Patent number: 7835101Abstract: A planar plasmon antenna is formed on a YZ plane including a Z-axis, the Z-axis being a propagation direction of excitation light for near-field light generation. The longitudinal direction of the planar plasmon antenna is oblique relative to the Y-axis, and the angle of a corner of the planar plasmon antenna in the YZ plane is an acute angle. The corner, which forms an acute angle, generates intense near-field light in response to excitation light irradiation.Type: GrantFiled: August 20, 2008Date of Patent: November 16, 2010Assignee: TDK CorporationInventors: Seiichi Takayama, Koji Shimazawa
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Patent number: 7826179Abstract: The invention provides a magneto-resistive effect device of the CPP (current perpendicular to plane) structure, comprising a magneto-resistive effect unit, and an upper shield layer and a lower shield layer located with that magneto-resistive effect unit sandwiched between them, with a sense current applied in a stacking direction, wherein the magneto-resistive effect unit comprises a nonmagnetic metal intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed with that nonmagnetic metal intermediate layer sandwiched between them, wherein the first ferromagnetic layer and said second ferromagnetic layer are exchange coupled via the nonmagnetic metal intermediate layer such that where there is no bias magnetic field applied as yet, their magnetizations are anti-parallel with each other, and at least one of the upper shield layer and the lower shield layer has an inclined magnetization structure with its magnetization inclining with respect to a track width directionType: GrantFiled: September 17, 2007Date of Patent: November 2, 2010Assignee: TDK CorporationInventors: Koji Shimazawa, Tsutomu Chou, Yoshihiro Tsuchiya
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Patent number: 7821732Abstract: A thermally assisted magnetic head according to the present invention includes: 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, wherein the plasmon antenna is shaped as a triangular flat plate having first, second and third corners, such that 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, and the interior angle ? of the first corner, the interior angle ? of the second corner and the interior angle ? of the third corner satisfy relationships ?<?, ?<? and ???.Type: GrantFiled: September 25, 2008Date of Patent: October 26, 2010Assignee: TDK CorporationInventors: Eiji Komura, Seiichi Takayama, Satoshi Tomikawa, Kosuke Tanaka, Koji Shimazawa
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Publication number: 20100259845Abstract: 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: ApplicationFiled: April 14, 2009Publication date: October 14, 2010Applicant: TDK CORPORATIONInventors: Daisuke MIYAUCHI, Susumu AOKI, Seiichi TAKAYAMA, Koji SHIMAZAWA, Tetsuya ROPPONGI