Patents by Inventor Shigekazu Otomo

Shigekazu Otomo 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: 7154714
    Abstract: A recording/reproducing separated type magnetic head comprising a first magnetic domain control layer for arranging the magnetizing direction of a free layer included in a magneto-resistive element to a predetermined direction, and a second magnetic domain control layer for generating a magnetic field in the direction opposite thereto to constitute a differential type bias structure. The recording/reproducing separated type magnetic head decreases an excessively strengthened longitudinal bias magnetic field in a central portion at a narrow track width while avoiding decrease of the fixed magnetic field at the end of the magneto-resistive element in the direction of the track width.
    Type: Grant
    Filed: June 19, 2003
    Date of Patent: December 26, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hiroshi Fukui, Shigekazu Otomo, Shuichi Kojima, Kouji Kataoka
  • Publication number: 20040047087
    Abstract: A recording/reproducing separated type magnetic head comprising a first magnetic domain control layer for arranging the magnetizing direction of a free layer included in a magneto-resistive element to a predetermined direction, and a second magnetic domain control layer for generating a magnetic field in the direction opposite thereto to constitute a differential type bias structure. The recording/reproducing separated type magnetic head decreases an excessively strengthened longitudinal bias magnetic field in a central portion at a narrow track width while avoiding decrease of the fixed magnetic field at the end of the magneto-resistive element in the direction of the track width.
    Type: Application
    Filed: June 19, 2003
    Publication date: March 11, 2004
    Inventors: Hiroshi Fukui, Shigekazu Otomo, Shuichi Kojima, Kouji Kataoka
  • Patent number: 6033792
    Abstract: A recording head for recording data onto a recording medium is provided with a thin film formed of the following compound Fe.sub.100-a-b-c X.sub.a Y.sub.b Z.sub.c, wherein X is at least one element selected from the group consisting of Nb, Ta, Hf and Zr, Y is one or two elements selected from the group consisting of Cr, Ru, Al, Si, Ti and Rh, and Z is at least one element selected from the group consisting of C and N, and wherein 5.ltoreq.a.ltoreq.20, 0.5.ltoreq.b.ltoreq.15, 1.ltoreq.c.ltoreq.20, and 0.5.ltoreq.a/c.ltoreq.0.7, the carbide or the nitride of the element X having an average grain size of not larger than 3 nm. This way, increased corrosion resistance is provided without substantially reducing magnetic characteristics such as saturation and coercive force. A recording apparatus, such as a VTR, including such a recording head is disclosed as well as a recording medium formed using this thin film.
    Type: Grant
    Filed: October 19, 1998
    Date of Patent: March 7, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Fumiyoshi Kirino, Shigekazu Otomo, Nagatugu Koiso, Noriyuki Kumasaka, Takeshi Miura
  • Patent number: 5873955
    Abstract: A recording head for recording data onto a recording medium is provided with a thin film formed of the following compound Fe.sub.100-a-b-c X.sub.a Y.sub.b Z.sub.c, wherein X is at least one element selected from the group consisting of Nb, Ta, Hf and Zr, Y is one or two elements selected from the group consisting of Cr, Ru, Al, Si, Ti and Rh, and Z is at least one element selected from the group consisting of C and N, and wherein 5.ltoreq.a.ltoreq.20, 0.5.ltoreq.b.ltoreq.15, 1.ltoreq.c.ltoreq.20, and 0.5.ltoreq.a/c.ltoreq.0.7, the carbide or the nitride of the element X having an average grain size of not larger than 3 nm. This way, increased corrosion resistance is provided without substantially reducing magnetic characteristics such as saturation and coercive force. A recording apparatus, such as a VTR, including such a recording head is disclosed as well as a recording medium formed using this thin film.
    Type: Grant
    Filed: February 1, 1996
    Date of Patent: February 23, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Fumiyoshi Kirino, Shigekazu Otomo, Nagatugu Koiso, Noriyuki Kumasaka, Takeshi Miura
  • Patent number: 5663006
    Abstract: A ferromagnetic film made of an alloy of FeMQC-R, wherein M is at least one element selected from Hf, Zr, Ta, Nb, W, Ti, Mo and V; Q is at least one element selected from Cr, Rh and Ru; and R is at least one rare earth element such as Sm, Nd, etc., is low in magneto-striction, high in saturation magnetic flux density, good in soft magnetic properties and excellent in corrosion resistance, and suitable for producing a magnetic head having a high and stable reproducing output for a long period of time.
    Type: Grant
    Filed: July 29, 1993
    Date of Patent: September 2, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Hitoshi Nakamura, Shigekazu Otomo
  • Patent number: 5463518
    Abstract: A magnetic head has a superconducting quantum interference device having a ring made of a superconductive material including a Josephson junction which links to a magnetic flux generated by a magnetic recording medium, and a magnetic pole for guiding the magnetic flux generated by the magnetic recording medium or the ring made of a superconductive material arranged in parallel to a plane of the magnetic recording medium so that the magnetic flux generated by the magnetic recording medium flows into a through-hole of the ring. A magnetic recording and reproducing apparatus includes such a magnetic head, a winding to which a reproduced signal from the magnetic head is applied and the superconductive ring including the Josephson junction arranged such that the magnetic flux generated by the winding flows thereto.
    Type: Grant
    Filed: March 22, 1991
    Date of Patent: October 31, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Kazuo Shiiki, Takeo Yamashita, Noritoshi Saito, Yoshinobu Tarutani
  • Patent number: 5247415
    Abstract: A magnetic head has a main magnetic path forming film forming an operation gap, and an auxiliary magnetic path forming film for complementing said main magnetic path forming film. The auxiliary magnetic path forming film is disposed behind the gap depth of said magnetic core and magnetically coupled to the main magnetic path forming film. The main magnetic path forming film has a direction of easy magnetization perpendicular to the direction of depth of the operation gap, while the auxiliary magnetic path forming film has a direction of easy magnetization which coincides with the direction in which said magnetic head opposes the recording medium.
    Type: Grant
    Filed: November 24, 1992
    Date of Patent: September 21, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Takeo Yamashita, Toshio Kobayashi, Ryoichi Nakatani, Shigekazu Otomo
  • Patent number: 5159505
    Abstract: A rotating drum for use in a magnetic recording system. A magnetic head is mounted on the rotating drum, and a magnetic recording medium is wound on the rotating drum, and the rotating drum is rotated so as to read and write signals. Alternatively, the magnetic recording medium is mounted on the rotating drum, and signals are read and written by a magnetic head fixed exteriorly of the rotating drum. The rotating drum has at least one opening or notch in a magnetic recording medium-winding surface thereof. In order to restrain the deformation of the rotating drum during the rotation thereof, the center of gravity of the drum is disposed substantially in registry with the axis of rotation of the drum.
    Type: Grant
    Filed: May 31, 1990
    Date of Patent: October 27, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Yasuaki Horiuchi, Kuninori Imai, Takeshi Tajima, Takeo Yamashita, Shigekazu Otomo, Noriyuki Kumasaka
  • Patent number: 4972285
    Abstract: An amorphous magnetic alloy of Co-Nb-Zr system contains Co, Nb and Zr and has a composition which falls, in terms of atomic percent, within the region defined by straight lines connecting, in a ternary composition diagram assuming the total of contents of these three elements to be 100, a point (81% Co, 14% Nb, 5 Zr), a point (88% Co, 9% Nb, 3% Zr), a point (86.5% Co, 12.5% Nb, 1% Zr) and a point (81% Co, 18% Nb, 1% Zr). Disclosed also is a magnetic head having a core at least a part of which is constituted by this amorphous magnetic alloy. This magnetic head, when used in combination with a metal powder tape having a high coercive force, provides a remarkably increased recording-reproducing output.
    Type: Grant
    Filed: July 12, 1988
    Date of Patent: November 20, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Hideo Fujiwara, Shinji Takayama, Takeo Yamashita, Noritoshi Saito, Mitsuhiro Kudo
  • Patent number: 4943879
    Abstract: A thin film magnetic head having a first magnetic layer of a saturation magnetic flux density greater than that of a Ni-Fe alloy and a second magnetic layer of a saturation magnetic flux density grater than that of a Ni-Fe alloy supported by a base layer, the magnetic layers for forming a magnetic core of the head with a non-magnetic material gap layer interposed therebetween, and an electrically insulating layer provided between the magnetic layers so that turns of coil wound about the magnetic core are partly formed in electrically insulated relation within the insulating layer, in which a metal film is provided between the first magnetic layer and the electrically insulating layer so that the electrically insulating layer does not contact with the first magnetic layer and/or another metal film is formed on the second magnetic layer so that the other metal layer is sandwiched between the non-magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: August 17, 1987
    Date of Patent: July 24, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Hisashi Takano, Yoshihiro Hamakawa, Kazuo Shiiki, Shigekazu Otomo, Noriyuki Kumasaka
  • Patent number: 4935311
    Abstract: Disclosed is a magnetic multilayered film in which layers of Fe or of an alloy containing Fe as an essential constituent are laminated together with intermediate layers of a nonmagnetic metal. In an embodiment of the magnetic multilayered film, each of the Fe layers or each of the Fe alloy layers is epitaxially grown on at least part of each of the intermediate layers of the nonmagnetic metal. A magnetic head having the magnetic multilayered film is also disclosed. The nonmagnetic metal is at least one of those selected from the group consisting of V, Cr, Cu, Nb, W, Al and Pt.
    Type: Grant
    Filed: April 13, 1988
    Date of Patent: June 19, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Toshio Kobayashi, Shigekazu Otomo, Noriyuki Kumasaka, Noritoshi Saito
  • Patent number: 4935314
    Abstract: An anti-corrosion ferromagnetic film and a magnetic head using the crystalline ferromagnetic film are disclosed. The anti-corrosion film contains an element interstitially soluble to iron, in addition to iron used as the main component, and further contains at least one element selected from the group consisting of Ni, Rh, Ru, Pd, Zr, Nb, Ta, Ag, Os, Ir, Pt, Au, Cr, Mo, W, Ti, Bi, V, Co and Cu, at a concentration value of 0.5 to 5 atomic percent.
    Type: Grant
    Filed: March 24, 1988
    Date of Patent: June 19, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Ryoichi Nakatani, Shigekazu Otomo, Noriyuki Kumasaka
  • Patent number: 4920013
    Abstract: A magnetic multilayer structure having an increased permeability and an increased saturation magnetic flux density comprises a plurality of magnetic layers and a plurality of intermediate layers alternately laminated one upon another. Each of the magnetic layers is made of Fe, Co, Ni or an alloy containing one of Fe, Co and Ni, while each of the intermediate layers is made of a material capable of interstitially forming a solid solution with the material of the magnetic layers.
    Type: Grant
    Filed: September 23, 1987
    Date of Patent: April 24, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Shigekazu Otomo, Ryoichi Nakatani, Noriyuki Kumasaka
  • Patent number: 4894098
    Abstract: Ion implantation is conducted in a desired area(s) of the surface of a magnetic layer, and annealing of the layer is carried out to control the composition in that desired area(s). The control of the composition may be facilitated by applying a one-directional or rotating magnetic field during ion implantation. In preparing a magnetic head, a portion of a magnetic pole at least on one side thereof in close proximity to a magnetic recording medium is formed into an iron or iron-based magnetic alloy film, at least part of which is subjected to ion implantation and annealing.
    Type: Grant
    Filed: July 28, 1988
    Date of Patent: January 16, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Ryo Imura, Ryo Suzuki, Yutaka Sugita
  • Patent number: 4891278
    Abstract: A ferromagnetic thin film containing Fe as a main component and at least one additive element selected from the group consisting of Co, Ni, Ru, Rh, Pd, Os, Ir and Pt, in which the total content of the at least one additive element is not less than 0.1 at % and additive contents, a, b, c, d, e, f, g and h (at %) respectively of said Co, Ni, Ru, Rh, Pd, Os, Ir and Pt satisfy ##EQU1## The ferromagnetic thin film thus disclosed has a high saturation flux density of 18 KG or more, a magnetostriction constant close to zero, and excellent corrosion resistance. There is also disclosed a magnetic head using the above described ferromagnetic thin film in at least a part of a magnetic circuit thereof.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: January 2, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Ryoichi Nakatani, Noriyuki Kumasaka, Noritoshi Saito, Toshio Kobayashi, Masahiko Fujishiro
  • Patent number: 4858049
    Abstract: A magnetic film and a magnetic head using the magnetic film are disclosed. The magnetic film is formed by adding one or more elements by 5 to 20 at. %, the elements being selected from B, N, C and P interstitially soluble to Fe to a magnetic film made of Fe or having Fe as its main component.
    Type: Grant
    Filed: June 1, 1987
    Date of Patent: August 15, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Shigekazu Otomo, Ryoichi Nakatani, Noriyuki Kumasaka
  • Patent number: 4851942
    Abstract: A core burying channel is formed on the outer side surface of an air bearing rail of a floating magnetic head floating on a magnetic disk by an air-flow in a direction perpendicular to a magnetic recording medium travelling direction, and a magnetic core is buried in this core burying channel. This magnetic head can be produced easily by a production method which forms a core burying channel in a non-magnetic block, then deposits a magnetic material to the core burying channel and removes unnecessary portions of the magnetic material.
    Type: Grant
    Filed: September 14, 1987
    Date of Patent: July 25, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Niroyuki Kumasaka, Shigekazu Otomo, Takeo Yamashita, Noritoshi Saito, Yokuo Saitoh, Hiroshi Sakurai
  • Patent number: 4847715
    Abstract: A tunnel erasing-type magnetic head having a short distance between the gaps, wherein a second core half is sandwiched between the first core half and the third core half, a magnetic gap for recording and reproducing the signals is formed between the first core half and the second core half, and a magnetic gap for erasing is formed between the second core half and the third core half, so that the second core half can be utilized for both recording and reproducing the signals and erasing the signals. The second core half is obtained by forming a thin magnetic film of a high saturation flux density on the base portion composed of a nonmagnetic material that forms the magnetic gap. The first and third core halves are also obtained by forming a thin magnetic film of a high saturation flux density on the magnetic gap surfaces of the base portions to produce performance that can be used for the magnetic recording media having high coercive force. The magnetic head has a short distance between the gaps.
    Type: Grant
    Filed: December 15, 1986
    Date of Patent: July 11, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Shigekazu Otomo, Takeo Yamashita, Noritoshi Saito
  • Patent number: 4814921
    Abstract: Multilayered magnetic films of the invention comprising at least two unit magnetic films each of which has a thickness of from 0.05 to 0.9 .mu.m and includes a plurality of ferromagnetic layers each having a thickness of from 0.01 to 0.2 .mu.m and a 1 nm to 10 nm thick first intermediate layer consisting of a ferromagnetic, nonmagnetic or antiferromagnetic material and provided between adjacent ferromagnetic layers, and a second intermediate layer having a thickness of from 10 to 40 nm, consisting of a nonmagnetic or antiferromagnetic material and provided between the at least two unit magnetic films. The multilayered magnetic film is suitable as a pole of a thin-film magnetic head. An underlayer may be further provided between the magnetic film and a substrate whereby a multilayered magnetic film having good characteristics can be obtained.
    Type: Grant
    Filed: February 1, 1988
    Date of Patent: March 21, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihiro Hamakawa, Kazuo Shiiki, Yoshihiro Shiroishi, Isamu Yuitoo, Hitoshi Numasaka, Noriyuki Kumasaka, Shigekazu Otomo, Eijin Moriwaki
  • Patent number: RE33022
    Abstract: A ferromagnetic amorphous alloy having a composition represented by (Co.sub.x Ni.sub.y Fe.sub.z).sub.a M.sub.b G.sub.c, wherein M is Cr, Mo and/or W, G is Zr, Hf and/or Ti and x,y,z and a, b, c are selected to meet the conditions of x=1-y-z, 0.ltoreq.y.ltoreq.0.2, 0.ltoreq.z.ltoreq.0.7, a=1-b-c, 0.ltoreq.b.ltoreq.0.05 and 0.05.ltoreq.c.ltoreq.0.2 This amorphous alloy has a superior magnetic characteristic and a high thermal stability.
    Type: Grant
    Filed: November 5, 1987
    Date of Patent: August 15, 1989
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd., Research Development Corp. of Japan
    Inventors: Shinji Takayama, Yasuo Tsukuda, Kazuo Shiiki, Shigekazu Otomo, Mitsuhiro Kudo, Yasunobu Ogata, Yoshizo Sawada