Patents by Inventor Chiharu Mitsumata

Chiharu Mitsumata 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: 8093886
    Abstract: A rotation-angle-detecting apparatus comprising a magnet rotor, a magnetic sensor detecting the direction of magnetic flux from the magnet rotor, a correction circuit, and an angle-calculating circuit, the magnetic sensor having bridge circuits X and Y each comprising four connected magnetoresistive devices, each magnetoresistive device comprising a spin-valve, giant-magnetoresistive film, the correction circuit calculating difference (Vx?Vy) and sum (Vx+Vy) from the output voltage Vx of the bridge circuit X and the output voltage Vy of the bridge circuit Y, and making their amplitudes equal to each other, and the angle-calculating circuit determining the rotation angle of the rotor by arctangent calculation from a signal (Vx?Vy)? and a signal (Vx+Vy)? supplied with the same amplitude from the correction circuit.
    Type: Grant
    Filed: March 26, 2010
    Date of Patent: January 10, 2012
    Assignee: Hitachi Metals, Ltd.
    Inventors: Yasuyuki Okada, Kyohei Aimuta, Chiharu Mitsumata
  • Patent number: 8054067
    Abstract: A magnetic sensor comprising a bridge circuit in which four magnetoresistive devices are connected, the magnetoresistive device comprising a spin-valve, giant-magnetoresistive film comprising a pinned layer having unidirectional magnetic anisotropy, a free layer whose magnetization direction is rotated in alignment with an external magnetic field direction, and an intermediate layer sandwiched by the pinned layer and the free layer, and at least one of the magnetoresistive devices meeting the condition of 36°??<45°, wherein ? is an acute angle between its longitudinal direction and the magnetization direction of the pinned layer.
    Type: Grant
    Filed: January 26, 2009
    Date of Patent: November 8, 2011
    Assignee: Hitachi Metals Ltd.
    Inventors: Yasuyuki Okada, Chiharu Mitsumata
  • Publication number: 20110037459
    Abstract: A rotation-angle-detecting apparatus comprising a magnet rotor, a magnetic sensor detecting the direction of magnetic flux from the magnet rotor, a correction circuit, and an angle-calculating circuit, the magnetic sensor having bridge circuits X and Y each comprising four connected magnetoresistive devices, each magnetoresistive device comprising a spin-valve, giant-magnetoresistive film, the correction circuit calculating difference (Vx?Vy) and sum (Vx+Vy) from the output voltage Vx of the bridge circuit X and the output voltage Vy of the bridge circuit Y, and making their amplitudes equal to each other, and the angle-calculating circuit determining the rotation angle of the rotor by arctangent calculation from a signal (Vx?Vy)? and a signal (Vx+Vy)? supplied with the same amplitude from the correction circuit.
    Type: Application
    Filed: March 26, 2010
    Publication date: February 17, 2011
    Applicant: Hitachi Metals, Ltd.
    Inventors: Yasuyuki Okada, Kyohei Aimuta, Chiharu Mitsumata
  • Publication number: 20090189601
    Abstract: A magnetic sensor comprising a bridge circuit in which four magnetoresistive devices are connected, the magnetoresistive device comprising a spin-valve, giant-magnetoresistive film comprising a pinned layer having unidirectional magnetic anisotropy, a free layer whose magnetization direction is rotated in alignment with an external magnetic field direction, and an intermediate layer sandwiched by the pinned layer and the free layer, and at least one of the magnetoresistive devices meeting the condition of 36°??<45°, wherein ? is an acute angle between its longitudinal direction and the magnetization direction of the pinned layer.
    Type: Application
    Filed: January 26, 2009
    Publication date: July 30, 2009
    Applicant: HITACHI METALS, LTD.
    Inventors: Yasuyuki OKADA, Chiharu MITSUMATA
  • Patent number: 7511679
    Abstract: A magnetic sensor-type antenna comprising a magnetic core and a coil wound around the magnetic core for receiving electromagnetic waves, which is disposed in a housing such that the end portion of the magnetic core is bent away from the housing or a metal portion of the housing, and a timepiece, a keyless entry system and an RFID system each comprising such an antenna.
    Type: Grant
    Filed: November 29, 2004
    Date of Patent: March 31, 2009
    Assignee: Hitachi Metals Ltd.
    Inventors: Hirokazu Araki, Masahiro Mita, Chiharu Mitsumata
  • Publication number: 20090054722
    Abstract: The present invention provides drug carriers having high heating efficiency by high-frequency dielectric heating in a state of being selectively accumulated in a target site. The drug carriers each consist of a drug, magnetic fine particles, and a shell containing the drug and the magnetic fine particles. The shell has an outer diameter in a range from 10 nm to 200 nm. The magnetic fine particles having an average particle diameter of d has a standard deviation ? of particle diameter distribution satisfying 0.8d>?>0.4d. The magnetic fine particles contained in the individual drug carriers generate hysteresis heat due to high-frequency dielectric heating by irradiation of a high-frequency magnetic field.
    Type: Application
    Filed: August 6, 2008
    Publication date: February 26, 2009
    Inventors: Ryoko Sugano, Nami Sugita, Teruo Kohashi, Keiji Takata, Chiharu Mitsumata, Shigeo Fujii
  • Patent number: 7463208
    Abstract: An antenna comprising a magnetic main-path member comprising a coil wound around a magnetic core, and a magnetic sub-path member magnetically connected to the magnetic core for constituting a substantially closed magnetic path with the magnetic main-path member, the antenna meeting the relation of (S/N)1>(S/N)0, wherein (S/N)1 is a ratio of a signal voltage S obtained from the coil to a noise voltage N in this antenna, and (S/N)0 is a ratio of a signal voltage S to a noise voltage N in an antenna having the same structure except for having no magnetic sub-path member.
    Type: Grant
    Filed: July 3, 2006
    Date of Patent: December 9, 2008
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hirokazu Araki, Chiharu Mitsumata, Masahiro Mita
  • Publication number: 20070024516
    Abstract: An antenna comprising a magnetic main-path member comprising a coil wound around a magnetic core, and a magnetic sub-path member magnetically connected to the magnetic core for constituting a substantially closed magnetic path with the magnetic main-path member, the antenna meeting the relation of (S/N)1>(S/N)0, wherein (S/N)1 is a ratio of a signal voltage S obtained from the coil to a noise voltage N in this antenna, and (S/N)0 is a ratio of a signal voltage S to a noise voltage N in an antenna having the same structure except for having no magnetic sub-path member.
    Type: Application
    Filed: July 3, 2006
    Publication date: February 1, 2007
    Inventors: Hirokazu ARAKI, Chiharu Mitsumata, Masahiro Mita
  • Publication number: 20060214866
    Abstract: A magnetic sensor-type antenna comprising a magnetic core and a coil wound around the magnetic core for receiving electromagnetic waves, which is disposed in a housing such that the end portion of the magnetic core is bent away from the housing or a metal portion of the housing, and a timepiece, a keyless entry system and an RFID system each comprising such an antenna.
    Type: Application
    Filed: November 29, 2004
    Publication date: September 28, 2006
    Inventors: Hirokazu Araki, Masahiro Mita, Chiharu Mitsumata
  • Patent number: 5910868
    Abstract: A magnetoresistive (MR) sensor for MR heads comprising a magnetoresistive ferromagnetic layer (MR layer) and an antiferromagnetic layer in direct contact with the surface of the MR layer. The MR layer has a face-centered-cubic (fcc) structure. The crystalline structure of the antiferromagnetic layer is the fcc structure in the vicinity of the interface of the MR layer and the antiferromagnetic layer, and continuously changes to a face-centered-tetragonal (fct) structure toward the surface opposite to the interface. The interface of the MR layer and the antiferromagnetic layer is continuous with respect to the crystalline structure due to the epitaxial growth of the antiferromagnetic layer on the surface of the MR layer.
    Type: Grant
    Filed: November 6, 1996
    Date of Patent: June 8, 1999
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hisao Kurosawa, Chiharu Mitsumata, Toshio Kobayashi, Shin Noguchi
  • Patent number: 5866212
    Abstract: A magnetoresistive (MR) sensor for MR heads comprising a magnetoresistive ferromagnetic layer (MR layer) and an antiferromagnetic layer in direct contact with the surface of the MR layer. The MR layer has a face-centered-cubic (fcc) structure. The crystalline structure of the antiferromagnetic layer is the fcc structure in the vicinity of the interface of the MR layer and the antiferromagnetic layer, and continuously changes to a face-centered-tetragonal (fct) structure toward the surface opposite to the interface. The interface of the MR layer and the antiferromagnetic layer is continuous with respect to the crystalline structure due to the epitaxial growth of the antiferromagnetic layer on the surface of the MR layer.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: February 2, 1999
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hisao Kurosawa, Chiharu Mitsumata, Toshio Kobayashi, Shin Noguchi
  • Patent number: 5764445
    Abstract: A magnetoresistive (MR) transducer is disclosed in which an exchange coupled anisotropy field is provided by an antiferromagnetic NiMn alloy in contact with the MR alloy. Improved exchange coupling is achieved using an MR layer and adjacent NiMn exchange coupling layer which have substantially fcc structure and a preferred {111} crystalline orientation. The exchange bias field is observed to correlate strongly with the structural order of the films. A preferred method of fabricating the MR transducer enhances the structural order of the layers during growth, thereby reducing a post-deposition anneal typically required in such processes. The preferred fabrication process further provides greater predictability and control over the resulting exchange coupling.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: June 9, 1998
    Assignee: Applied Magnetics Corporation
    Inventors: Chyu Jiuh Torng, Chiharu Mitsumata
  • Patent number: 5754376
    Abstract: A magnetoresistive (MR) head for sensing magnetic data recorded on a magnetic recording medium with high track density and high linear density includes a magnetoresistive conductive layer (MR layer), a soft magnetic layer (SAL) for transversely biasing the MR layer and hard magnet layers for longitudinally biasing and controlling magnetization in the central sensing regions of the MR layer and the SAL. The longitudinal bias applied to the SAL is less than that to the MR layer so that a sensing current produces an effective magnetic field to saturate the SAL transversely. So, magnetization in the MR layer is kept at an angle of 40 to 45 degrees to easy magnetization direction of the MR layer and the improved reproducing output is obtained.
    Type: Grant
    Filed: September 12, 1996
    Date of Patent: May 19, 1998
    Assignee: Hitachi Metals, Ltd.
    Inventors: Toshio Kobayashi, Chiharu Mitsumata
  • Patent number: 5748416
    Abstract: An SAL-type magnetoresistive playback head that is highly sensitive and that limits Barkhausen noise is provided by optimizing the magnetic properties of the permanent magnet film. On top of a lower insulating layer are stacked a soft magnetic bias film (SAL film), a magnetic separating film (shunt film), a magnetoresistive film (MR film), and an upper insulating layer, in that order. The outer sides of the track of the MR film are in direct contact with the permanent magnet film or in indirect contact via a base film. Alternatively, the present invention relates to a spin-valve magnetoresistive playback head. On top of a lower insulating layer are stacked an anti-ferromagnetic film, a fixed magnetizing film, a magnetic separating film, a movable magnetizing film (MR film), and an upper insulating layer, in that order. The outer sides of the track of the movable magnetizing film are in direct contact with the permanent magnet film or in indirect contact via a base film.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: May 5, 1998
    Assignees: Hitachi Metals Ltd., Applied Magnetics Corporation
    Inventors: Masahiro Tobise, Chiharu Mitsumata, Hisayuki Miura, Tetsurou Kawai, Simon Liao
  • Patent number: 5576912
    Abstract: In a floating magnetic head, noises produced at the time of reproduction are reduced, thereby enhancing the precision of detection of a track position. The floating magnetic head uses a monocrystal magnetic material constituting an electromagnetic transducer element, and a crystal orientation of the monocrystal magnetic material in the electromagnetic transducer element is parallel to a direction of travel of a medium. In the case of .vertline..lambda..sub.111 .vertline.+2.times.10.sup.-6 .ltoreq..vertline..lambda..sub.100 .vertline., the crystal orientation is in the range of a solid angle of 3.multidot.sin.theta..multidot.cos.phi. which satisfies 0.ltoreq..theta.<10 degrees and 0.ltoreq..phi..ltoreq.360 degrees around [111], and in the case of .vertline..lambda..sub.111 .vertline..gtoreq..vertline..lambda..sub.100 .vertline.+2.times.10.sup.-6, the crystal orientation is in the range of a solid angle of sin .theta..multidot.cos.phi. which satisfies 0.ltoreq..theta.<10 degrees and 0.ltoreq..phi..ltoreq.
    Type: Grant
    Filed: May 11, 1994
    Date of Patent: November 19, 1996
    Assignee: Hitachi Metals Limited
    Inventors: Chiharu Mitsumata, Masanobu Yamazaki, Ryo Goto
  • Patent number: 5508863
    Abstract: A flying-type magnetic head includes a magnetic head chip composed of a pair of cores, each having a metallic magnetic thin film thereon which faces a magnetic gap. The magnetic chip is inserted and fixed in a slit provided in a non-magnetic slider at the outlet side of a magnetic recording medium generating airflow across an air bearing. The back of the slider is fixed to a gimbal in such a manner that a flying plane portion of the magnetic head faces the magnetic recording medium. The height at the flying plane portion of the slider is structurally controlled such that the height where the back of the slider is fixed to the gimbal differs by 20 nm or less with respect to the height thereof when the back of the slider is not fixed to the gimbal. The magnetic head chip may be composed of a pair of non-magnetic cores, each of which has a metallic magnetic thin film deposited thereon.
    Type: Grant
    Filed: July 29, 1994
    Date of Patent: April 16, 1996
    Assignee: Hitachi Metals, Ltd.
    Inventors: Ryo Goto, Chiharu Mitsumata