Patents by Inventor Mitsuhiro Kudo

Mitsuhiro Kudo 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: 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: 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: 4762755
    Abstract: A ferromagnetic material is composed of an iron alloy which contains 2 to 12% by weight of silicon and 5 to 25% by weight of at least one element selected from the group consisting of ruthenium, rhodium, palladium, iridium, platinum, gold and silver. This ferromagnetic material exhibits a high saturation flux density and good corrosion resistance. Excellent magnetic characteristics are obtained by a multilayered film which is obtained by alternatingly laminating the above ferromagnetic material and a spacer layer composed of other material. Further, a markedly increased recording density is exhibited by a magnetic head for perpendicular magnetic recording, when the end of the main pole is composed of the ferromagnetic material.
    Type: Grant
    Filed: October 29, 1984
    Date of Patent: August 9, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Kazuo Shiiki, Noriyuki Kumasaka, Yoshihiro Shiroishi, Hitoshi Nakamura, Yoshihiro Hamakawa, Noritoshi Saito, Shigeo Aoki, Kiminari Shinagawa, Mitsuhiro Kudo
  • 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: 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: 4668310
    Abstract: Amorphous alloys having high strength, high hardness, high crystallization temperature, high saturation magnetic induction, low coercive force, high magnetic permeability and particularly low deterioration of magnetic properties with lapse of time, have a composition formula ofT.sub.a X.sub.b Z.sub.c or T.sub.a' X.sub.b' Z.sub.c' M.sub.d,whereinT is at least one of Fe, Co and Ni,X is at least one of Zr, Ti, Hf and Y,Z is at least one of B, C, Si, Al, Ge, Bi, S and P,a is 70-98 atomic %,b is not more than 30 atomic %,c is not more than 15 atomic %,sum of a, b and c is 100 atomic %,M is at least one Mo, Cr, W, V, Nb, Ta, Cu, Mn, Zn, Sb, Sn, Be, Mg, Pd, Pt, Ru, Os, Rh, Ir, Ce, La, Pr, Nd, Sm, Eu, Gd, Tb and Dy,a' is 70-98 atomic %,b' is not more than 30 atomic %,c' is not more than 15 atomic %,d is not more than 20 atomic %, andsum of a', b', c' and d is 100 atomic %.
    Type: Grant
    Filed: March 14, 1983
    Date of Patent: May 26, 1987
    Assignees: Hitachi Metals, Ltd., Hitachi, Ltd.
    Inventors: Mitsuhiro Kudo, Shinji Takayama, Yoshizo Sawada, Yasunobu Ogata
  • 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: 4539616
    Abstract: Herein disclosed is a thin film magnetic head which is so constructed that a conductor layer arranged in a non-magnetic insulating layer isolating two magnetic poles and adapted to form a coil of plural turns has a height made larger than the width and gap thereof. A method of fabricating that head includes the step of forming a non-magnetic insulating layer, the step of etching the insulating layer by using a mask layer formed thereover as a mask, the step of depositing a metal for providing a conductor layer, the step of removing the mask layer together with the metal thereover, and the step forming a coating of a non-magnetic insulating layer thereover, thereby to form the conductor layer. The head thus fabricated has its magnetic recording and reproducing characteristics improved.
    Type: Grant
    Filed: July 20, 1982
    Date of Patent: September 3, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Isamu Yuito, Kazuo Shiiki, Atsushi Saiki, Yoshio Homma, Noriyuki Kumasaka, Yoshihiro Shiroishi, Mitsuhiro Kudo
  • Patent number: 4450494
    Abstract: A magnetic head having a magnetic core formed by facing a pair of magnetic substances through a working gap at a head section confronting a magnetic recording medium is disclosed in which at least one of the magnetic substances has magnetic anisotropy, and an angle .alpha. (in a C-shaped core half) and/or an angle .alpha.' (in an I-shaped core half) between a core surface confronting the magnetic recording medium and a direction having a maximum magnetic permeability in a main magnetic circuit plane of the magnetic substance having magnetic anisotropy is made larger than an orientation angle of the above direction for making minimum the magnetic reluctance of the main magnetic circuit of the magnetic core by .beta. (for .alpha.) and/or .beta.' (for .alpha.') to improve the recording/reproducing characteristic of the magnetic head, where .beta. is given by a formula ##EQU1## is equal to or less than 25.degree.
    Type: Grant
    Filed: September 22, 1981
    Date of Patent: May 22, 1984
    Assignee: Hitachi Ltd.
    Inventors: Hideo Fujiwara, Mitsuhiro Kudo, Teizo Tamura, Nobuyuki Sugishita, Yoshihiro Shiroishi, Takeshi Kimura, Kiminari Shinagawa, Noriyuki Kumasaka
  • Patent number: 4439794
    Abstract: A magnetic head which uses single crystal Mn-Zn ferrite containing up to 7% by weight of SnO.sub.2 occluded therein without being allowed to separate and which has such a construction that glass having a contraction rate lower than that of ferrite is filled in the narrowed portion near the gap, the plane forming the principal magnetic circuit of the core is allowed to coincide with the {110} plane of the ferrite and an angle .theta. between the <100> direction inside the {110} plane of the ferrite and the gap-forming plane is from 5.degree. to 40.degree. or 85.degree. to 120.degree.. The magnetic head having such a construction has a reduced modulation noise and extremely excellent write-and-read characteristics.
    Type: Grant
    Filed: May 18, 1981
    Date of Patent: March 27, 1984
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd.
    Inventors: Yoshihiro Shiroishi, Hideo Fujiwara, Takeshi Kimura, Noriyuki Kumasaka, Nobuo Kobayashi, Takeo Yamashita, Teizo Tamura, Hideo Zama, Mitsuhiro Kudo, Tsutomu Iimura
  • 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: 4316228
    Abstract: In a magnetic head a single-crystal Mn--Zn ferrite is employed as a core material, and cut-away parts in the vicinities of a gap are filled with a glass the contraction rate of which is lower than that of the ferrite. A principal magnetic circuit-forming plane of the core is brought into agreement with the {1 1 0} plane of the ferrite, while an angle .theta. defined between the <1 0 0> direction within the {1 1 0} plane of the ferrite and a gap forming plane is made 5.degree.-40.degree. or 80.degree.-120.degree.. The magnetic head thus constructed exhibits very favorable write and read characteristics.
    Type: Grant
    Filed: December 3, 1979
    Date of Patent: February 16, 1982
    Assignee: Hitachi, Ltd.
    Inventors: Hideo Fujiwara, Mitsuhiro Kudo, Teizou Tamura, Nobuyuki Sugishita, Yoshihiro Shiroishi, Takeshi Kimura, Kiminari Shinagawa, Noriyuki Kumasaka
  • 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: 4301353
    Abstract: A method for producing a magnetic head, comprising the step of irradiating peripheral parts other than a track portion and/or a slider portion with a laser beam so as to selectively remove surface parts of the irradiated parts, thereby to form the track portion and/or the slider portion. According to this method, the track portion and/or the slider portion of the magnetic head can be worked at high working rate, at high precision and with low working deformation, with the result that the magnetic head of excellent reproduced output and crosstalk characteristics can be readily manufactured.
    Type: Grant
    Filed: February 28, 1980
    Date of Patent: November 17, 1981
    Assignee: Hitachi, Ltd.
    Inventors: Masahide Suenaga, Noboru Shimizu, Mitsuhiro Kudo, Hiroshi Yamaguchi, Masao Mitani
  • 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