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: 4803338
    Abstract: In a magnetic head employing a metallic ferromagnetic material for portions defining a transducing gap, an oxide film or carbide film and a nonmagnetic metal film are provided in this order on each of track width narrowing grooves, and glass is packed on the nonmagnetic metal film, thereby preventing the deteriorations of magnetic characteristics ascribable to the reaction between the metallic ferromagnetic material and the glass and the production of bubbles ascribable to the reaction between the protective films and the glass, and to achieve the enhancements of recording and reproducing characteristics, the prevention of damages to a recording medium surface, the increase of a head lifetime and the rise of the available percentage of manufacture of the heads. When a glass film is further provided on the nonmagnetic metal film and the glass is packed thereon, more excellent effects are achieved.
    Type: Grant
    Filed: January 6, 1987
    Date of Patent: February 7, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Shigekazu Otomo, Takeo Yamashita, Hideo Zama, Juichi Morikawa
  • Patent number: 4774616
    Abstract: The present invention relates to a magnetic head, which can form guard bands on a magnetic recording medium and which is especially suitable for magnetic discs, and a fabrication process thereof. The magnetic core of the present invention includes a recording and reproduction head core (31) and an erasure head core (32) which is integrally joined in series to the head core (31) for forming guard bands. Magnetic circuits are constructed of metallic magnetic materials (34), (34'), (35) and (35') formed on non-magnetic members (33) and (33'). As a result, a recording medium having high coercive forces can be recorded while the track width is reduced and the fabrication is facilitated with a high accuracy.
    Type: Grant
    Filed: December 4, 1984
    Date of Patent: September 27, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Hideo Fujiwara, Shigekazu Otomo, Takeo Yamashita, Noritoshi Saito, Mitsuhiro Kudo
  • Patent number: 4772976
    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: August 23, 1985
    Date of Patent: September 20, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Ryo Imura, Ryo Suzuki, Yutaka Sugita
  • Patent number: 4769729
    Abstract: A magnetic head includes ferromagnetic amorphous alloy multi-layer films each composed of an alternate lamination of ferromagnetic amorphous alloy layers and magnetic spacer layers. The thickness of each ferromagnetic amorphous alloy layer is of 1 .mu.m to 10 .mu.m. The thickness of each magnetic spacer layer is of 0.01 .mu.m to 0.2 .mu.m. The ferromagnetic amorphous alloy multi-layer films constitute at least parts of the head core.
    Type: Grant
    Filed: June 10, 1986
    Date of Patent: September 6, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Shigekazu Otomo, Takeo Yamashita, Noritoshi Saito
  • Patent number: 4766039
    Abstract: A magnetic head comprising a magnetic film in at least a part of a magnetic circuit, at least a part of the magnetic film being formed in contact with, or being exposed to, an oxide or oxygen at least in a heating step at 150.degree. C. or higher in a process for preparing the magnetic head is disclosed. An amorphous alloy film for the magnetic film has the following composition formula to give distinguished head characteristics without any oxidation:Co.sub.a T.sub.b Zr.sub.c N.sub.dwhere T is at last one of Nb, Ta, W, Mo, V and Cr; N is at least one of Au, Pt and Ag; d.gtoreq.1, b>0, b.sub.1 +b.sub.2 +2c.gtoreq.10, a+d.gtoreq.80, -1.ltoreq.(3c-b.sub.1 -3b.sub.2 -5b.sub.3 -3b.sub.4 -4d)/(c+b.sub.1 +b.sub.2 +b.sub.3 +b.sub.4 +d).ltoreq.1, and a+b+c+d=100, where b.sub.1 is a Nb concentration, b.sub.2 is a Ta concentration, b.sub.3 is a W concentration, b.sub.4 is sum total of Mo, Cr and V concentrations and b=b.sub.1 +b.sub.2 +b.sub.3 +b.sub.4.
    Type: Grant
    Filed: June 17, 1986
    Date of Patent: August 23, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Noritoshi Saito, Takeo Yamashita, Kazuo Shiiki, Yoshihiro Hamakawa
  • Patent number: 4748089
    Abstract: A multilayered ferromagnetic amorphous alloy film is constituted by a plurality of main ferromagnetic material alloy films of a ferromagnetic amorphous alloy laminated one upon another with a spacer ferromagnetic material layer interposed therebetween, the spacer ferromagnetic material layer being of a ferromagnetic material different from the ferromagnetic alloy. Also disclosed is a magnetic head employing the above-described multilayered film for, at least, a portion of a core thereof. The multilayered film has excellent magnetic characteristics and is easily patterned.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: May 31, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Kazuo Shiiki, Shigekazu Otomo, Yoshihiro Shiroishi, Takeo Yamashita, Noritoshi Saito, Kiminari Shinagawa, Mitsuhiro Kudo
  • Patent number: 4745507
    Abstract: A composite type magnetic head wherein a functional gap is formed by a pair of opposing magnetic metal substance members coupled to a substrate of a nonmagnetic substance and include a head front surface facing a magnetic recording medium. A coil portion is provided rearwardly of the head front surface and includes a coil window provided between the pair of magnetic metal substance members and a coil for encircling both the nonmagnetic substance substrate and at least one of the magnetic metal substance members coupled to the substrate. A rear core portion is provided rearwardly of the coil portion and is magnetically coupled with the magnetic metal substance members, the rear core portion including at least a part made of a high permeability ferrite.
    Type: Grant
    Filed: February 5, 1986
    Date of Patent: May 17, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Takeo Yamashita, Juichi Morikawa, Hideo Fujiwara, Osamu Inagoya, Takeshi Tottori, Masashi Hayashi
  • Patent number: 4731683
    Abstract: The invention discloses a magnetic recording and reproducing system using a composite magnetic head whose surface facing a magnetic recording medium is composed primarily of a ferromagnetic metal and a high permeability ferrite single crystal, and which has a region close to a gap and composed of the ferromagnetic metal, wherein the composite magnetic head is arranged in such a fashion that the {110} plane of the high permeability ferrite single crystal is made to substantially coincide with a plane forming a principal magnetic circuit of the composite magnetic head, that the <100> direction lying inside the {110} plane is inclined at an angle of from 15.degree. to 75.degree.
    Type: Grant
    Filed: April 19, 1985
    Date of Patent: March 15, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Noriyuki Kumasaka, Takeo Yamashita, Juichi Morikawa, Takayuki Kobayashi, Mitsuhiro Kudo
  • Patent number: 4701819
    Abstract: A magnetic head having a pair of core halves each combined through a magnetic gap, each of the core halves comprising a core base having slanted side surfaces on the side opposing to the magnetic gap and a magnetic thin layer formed on the surfaces of the core base on the side opposing the magnetic gap with magnetic material of high saturation magnetic flux density, the minimum value of the sum of products of vertical cross sectional areas of the respective magnetic paths of each of the core halves except for the path of the magnetic gap and the respective saturation magnetic flux densities of the respective parts is greater than the product of the area of the magnetic gap and the saturation magnetic flux density of the magnetic thin layer.
    Type: Grant
    Filed: September 19, 1985
    Date of Patent: October 20, 1987
    Assignees: Hitachi Maxell, Ltd., Hitachi, Ltd.
    Inventors: Osamu Inagoya, Hideo Fujiwara, Takeshi Tottori, Minoru Yamano, Noriyuki Kumasaka, Shigekazu Otomo, Mitsuhiro Kudo, Juiti Morikawa, Kiyoshi Ishihara, Akira Usui, Masashi Hayashi
  • Patent number: 4656547
    Abstract: There is provided a structure of a composite type magnetic head and its manufacturing method. The composite type magnetic head comprises: two high permeability ferrite blocks with projections having nearly edged sections formed thereon; magnetic films having a high saturation flux density deposited on the side faces of the projections, the magnetic films confronting each other via a functional gap near front ends of said projections; guard films deposited over the magnetic films comprising a non-magnetic material; and non-magnetic materials filled on the guard films up to side face of the coil. This magnetic head exhibits excellent recording and reproducing characteristics. The contour effect is negligibly small. The reaction between the magnetic film and the non-magnetic material is prevented by the guard film.
    Type: Grant
    Filed: May 9, 1984
    Date of Patent: April 7, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Hideo Fujiwara, Shigekazu Otomo, Takeo Yamashita, Shinji Takayama, Noritoshi Saito, Mitsuhiro Kudo
  • Patent number: 4610935
    Abstract: A magnetic film structure comprises at least one magnetic film unit wherein a plurality of main magnetic films of 0.05 to 0.5 .mu.m thickness made of a magnetic alloy containing iron or cobalt as principal constituent and having a high saturation magnetic induction of 10,000 gauss or more and a magnetostriction of 10.sup.-6 or less are laminated through intermediate magnetic films made of a magnetic material such as a nickel and iron alloy or amorphous magnetic alloy different from that of the main magnetic film and being so thin that the influence of coercive force of the intermediate magnetic film does not come out. A plurality of the magnetic film units are also laminated through non-magnetic insulating films. The magnetic film structure has high saturation magnetic induction and low coercive force.
    Type: Grant
    Filed: January 16, 1984
    Date of Patent: September 9, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Hideo Fujiwara, Noritoshi Saito, Shigekazu Otomo, Takeo Yamashita, Mitsuhiro Kudo
  • Patent number: 4571652
    Abstract: A magnetic recording and reproducing apparatus comprises a magnetic head having magnetic cores in which at least portions thereof in the vicinity of a gap are made of M.sub.n -Z.sub.n ferrite single crystal and planes of the magnetic cores forming a principal magnetic circuit are formed by {110} planes of the ferrite and <100> directions contained in the {110} planes are inclined to a surface facing a magnetic recording medium, and means for relatively moving the magnetic recording medium in an opposite and parallel direction to a projection vector on said surface facing said recording medium, of a vector directed from a site far from the surface facing the magnetic recording medium to a site near said surface in the <100> direction projected on the surface facing the magnetic recording medium. The present magnetic recording and reproducing apparatus exhibits both high wear resistance and excellent read/write characteristic.
    Type: Grant
    Filed: November 24, 1982
    Date of Patent: February 18, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Hideo Fujiwara, Shigekazu Otomo, Kiminari Shinagawa, Noriyuki Kumasaka, Takeo Yamashita, Mitsuhiro Kudo, Teizo Tamura
  • Patent number: 4559572
    Abstract: A magnetic head core and a method of fabricating same, wherein a magnetic circuit is constituted by a pair of magnetic films having a V-shaped cross section which face each other at each protrudent section through the gap material. The cross-sectional portion of the V-shaped film is exposed to the surface facing the magnetic recording medium. The protrusions of the magnetic film pair have tip planes parallel to each other and substantially perpendicular to the moving direction of the magnetic recording medium. The tip plane has a width defined by the line of intersection between the plane and the surface facing the magnetic recording medium in correspondence to the recording track width. At least one of the magnetic films has a window for winding an excitation coil. The magnetic film is formed on the non-magnetic protection member having a V-shaped protrusion.
    Type: Grant
    Filed: January 31, 1984
    Date of Patent: December 17, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Hideo Fujiwara, Shigekazu Otomo, Takeo Yamashita, Shinji Takayama, Noritoshi Saito, Nobuo Kobayashi, Mitsuhiro Kudo
  • Patent number: 4420348
    Abstract: Amorphous alloy for magnetic head core represented by the general formula, (Fe.sub.x Co.sub.1-x).sub.a Cr.sub.b Si.sub.c -B.sub.1-a-b-c, where the value of x is 0.04-0.07, the value of a is 0.73-0.75, the value of b is 0.005-0.03, and the value of c is 0.02-0.06. The present amorphous alloy has high permeability, high saturation flux density, low magnetostriction, and low magnetic after-effect at the same time, and has distinguished characteristics for magnetic head core.
    Type: Grant
    Filed: March 27, 1981
    Date of Patent: December 13, 1983
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd., Research Development Corporation of Japan
    Inventors: Kazuo Shiiki, Shigekazu Otomo, Mitsuhiro Kudo, Mitsuo Abe
  • Patent number: 4411716
    Abstract: Amorphous alloys for magnetic head cores of a composition which is expressed by a general formula (Co.sub.x Fe.sub.1-x).sub.a Cr.sub.b Si.sub.c B.sub.1-a-b-c wherein the value of x is in the range between 0.925 and 0.97, the value of a is in the range between 0.74 and 0.76, the value of b is in the range between 0.005 and 0.03 and the value of c is in the range between 0.06 and 0.18, and wherein a+b+c.ltoreq.0.94, and a magnetic head for video equipment wherein at least one foil of one of the aforesaid alloys having a width of below 30 .mu.m is used. The amorphous alloys of the aforesaid composition are high in permeability, high in saturation magnetic flux density and low in magnetostriction. A magnetic head for video equipment using such alloys has excellent characteristics in that it has high recording and reproducing characteristics and a high output/noise ratio and shows little magnetic after effect.
    Type: Grant
    Filed: July 13, 1981
    Date of Patent: October 25, 1983
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd., Research Development Corporation of Japan
    Inventors: Kazuo Shiiki, Shigekazu Otomo, Mitsuhiro Kudo, Takeshi Kimura, Noriyuki Kumasaka, Hideo Fujiwara
  • Patent number: 4306908
    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: September 19, 1980
    Date of Patent: December 22, 1981
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd., Hitachi Research Dev. Corp.
    Inventors: Shinji Takayama, Yasuo Tsukuda, Kazuo Shiiki, Shigekazu Otomo, Mitsuhiro Kudo, Yasunobu Ogata, Yoshizo Sawada
  • Patent number: 4298381
    Abstract: Abrasion-resistive, high permeability magnetic alloy consisting essentially of 6-9 wt. % of Si, 7-11 wt. % of Al, 2-5 wt. % of Cr, 0.05-2 wt. % of Ti, 0.02-0.3 wt. % of at least one member selected from P and C, and the balance of Fe. The alloy is suitable as a core material for a magnetic head.
    Type: Grant
    Filed: December 18, 1979
    Date of Patent: November 3, 1981
    Assignee: Hitachi Denshi Kabushiki Kaisha
    Inventors: Mitsuhiro Kudo, Shigekazu Otomo, Hirotomo Ogihara, Yoshio Aoki