Patents by Inventor Tadahiko Kobayashi

Tadahiko Kobayashi 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: 6369992
    Abstract: A magneto-resistance effect head records and reproduces recorded magnetic material. The magneto-resistance effect head has a magneto-resistance effect film connected to a pair of leads. Additionally, a magnetic yoke, with a first and second magnetic yoke member, directs a signal magnetic field from a recording medium to the magneto-resistance effect film. The magneto-resistance effect head is constructed such that the first and second magnetic yoke members have surfaces that face the recording medium. The surfaces of the first and second magnetic yoke members have a magnetic gap between them. Additionally, the magneto-resistance effect film is recessed from the medium facing surfaces by a predetermined distance. Moreover, the first and second magnetic yoke members are aligned almost in parallel with the magnetic flux flow from the recording medium to the first magnetic yoke member, the magneto-resistance effect film, and the second magnetic yoke member.
    Type: Grant
    Filed: August 12, 1997
    Date of Patent: April 9, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Yoda, Atsuhito Sawabe, Hitoshi Iwasaki, Yuichi Ohsawa, Masashi Sahashi, Tadahiko Kobayashi
  • Patent number: 6333840
    Abstract: There is provided a magnetic recording apparatus capable of carrying out signal reproduction with high accuracy by using a narrow gap head structure corresponding to high recording density. An asymmetric gap structure MR head includes a magnetoresistance element 26 having a magnetoresistance film 24 and a pair of electrodes 25 disposed at the upper side; a reproducing magnetic gap film 23 disposed only at the lower side of the magnetoresistance element 26; a magnetic shielding film 22 disposed so as to make a laminate with the magnetoresistance element 26 through the reproducing magnetic gap film 23; and an insulating film 27 disposed at the upper side of the magnetoresistance element 26. When a signal is read by use of such a reproducing head, the signal of the present bit is read by subtracting a value obtained by multiplying signals of a plurality of previous bits by predetermined coefficients from the present reproduction signal.
    Type: Grant
    Filed: March 16, 1999
    Date of Patent: December 25, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Yoda, Tadahiko Kobayashi, Kohichi Tateyama, Hiromi Sakata
  • Patent number: 6304415
    Abstract: At least one magnetic pole out of a pair of magnetic poles is provided with a T-shaped magnetic pole having a magnetic pole chip at the position contacting with a magnetic gap and an auxiliary magnetic pole which is wider than thereof. The proximity of an air bearing surface of the T-shaped magnetic pole is composed of a laminated film containing a magnetic material layer with a high saturated magnetic flux density which composes the magnetic pole chip and a portion of the auxiliary magnetic pole and a magnetic material layer with a low saturated magnetic flux density which composes the remaining portion of the auxiliary magnetic pole. When the front portion of the magnetic pole with the track width of 1.8 &mgr;m or less is composed of a laminated film containing a magnetic material layer having a high saturated magnetic flux density and a magnetic material layer having a low saturated magnetic flux density, the thickness of the magnetic material layer having the high saturated magnetic flux density is 0.
    Type: Grant
    Filed: July 13, 2000
    Date of Patent: October 16, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohichi Tateyama, Hiroaki Yoda, Tadahiko Kobayashi, Hiromi Sakata, Michiko Hara, Akio Hori, Takashi Koizumi, Tomohiko Nagata
  • Publication number: 20010022259
    Abstract: The magnetic powder for validity determining ink is composed of magnetic oxide powder having a Curie temperature between −50° C. and 150° C. and a mean powder particle diameter of 10 &mgr;m or less.
    Type: Application
    Filed: March 9, 2001
    Publication date: September 20, 2001
    Inventors: Takao Sawa, Katsutoshi Nakagawa, Teruo Murakami, Tadahiko Kobayashi, Hisashi Takahashi, Masao Obama
  • Publication number: 20010018938
    Abstract: Giant magnetostrictive material, with an alloy including a rare earth element and a transition metal element, is obtained by dissolving nitrogen interstitially in the alloy. Nitrogen is introduced in the alloy in the range from 0.01 to 2.5% by mass. Nitrogen introducing treatment is carried out at a temperature of 600° C. or less. A content of nitrogen compound present in magnetostrictive alloy, by a ratio of a content of nitrogen in the nitrogen compound to a total nitrogen content in the alloy, is reduced to be 0.05 or less by mass ratio. Almost all of the added nitrogen is interstitially dissolved between crystal lattice. In giant magnetostrictive material using melt quench flakes, the flakes are stacked in a thickness direction that is a direction of growth of columnar grain essentially constituting the flake material to integrate in this state.
    Type: Application
    Filed: February 9, 2001
    Publication date: September 6, 2001
    Inventors: Tomohisa Arai, Hideki Yamamiya, Masami Okamura, Tadahiko Kobayashi
  • Patent number: 6256863
    Abstract: A magnetic yoke having a magnetic gap provided in the side of the surface facing the medium is disposed on the surface of a substrate. An MR film is disposed on the surface of the magnetic yoke substantially parallel to the substrate with a predetermined separation from the surface S facing the medium. At least both end portions of the MR film are magnetically coupled to the magnetic yoke. A pair of leads for supplying sensing current to the MR film have magnetic lead portions formed from the same magnetic layers as the magnetic yoke. The magnetic lead portions curb deterioration of MR head properties and yield reduction during formation of the leads. Furthermore, a bias magnetic field is applied to the magnetic yoke and the MR film at least during operation of the head. This bias magnetic field is for instance provided by a magnetic field induced by the electric current. Alternatively, a magnetic field induced by the electric current is applied while heat-processing the magnetic yoke.
    Type: Grant
    Filed: March 11, 1997
    Date of Patent: July 10, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuhiro Saito, Akiko Saito, Hitoshi Iwasaki, Akihiko Tsutai, Hiroaki Yoda, Tadahiko Kobayashi, Yuichi Ohsawa, Masahi Sahashi, Yuzo Kamiguchi
  • Patent number: 6198597
    Abstract: A thin-film magnetic head comprises a magnetic gap disposed to be positioned on an air bearing surface of the magnetic head, a pair of magnetic poles disposed to hold the magnetic gap therebetween, and a coil positioned between the pair of the magnetic poles to intersect the magnetic poles, wherein at least one of the magnetic poles being composed of a T-shaped magnetic pole, the T-shaped magnetic pole comprising a front part of a magnetic pole contacting with the magnetic gap, an intermediate part of a magnetic pole lying on the front part, and a rear part of a magnetic pole lying on the intermediate part, wherein a width of the front part roughly defines a track width, the rear part has a wider width in a direction of track width than a width of the front part, and the intermediate part contacts with the rear part at an entire width of the rear part at the air bearing surface and has a narrower width at a contacting face with the front part than the width of the rear part.
    Type: Grant
    Filed: September 16, 1998
    Date of Patent: March 6, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohichi Tateyama, Hiroaki Yoda, Atsuhito Sawabe, Naoyuki Inoue, Akio Hori, Tadahiko Kobayashi, Hiromi Sakata, Michiko Hara, Takasi Koizumi, Tomohiko Nagata, Takeo Sakakubo, Kei Sakoda
  • Patent number: 6108167
    Abstract: At least one magnetic pole out of a pair of magnetic poles is provided with a T-shaped magnetic pole having a magnetic pole chip at the position contacting with a magnetic gap and an auxiliary magnetic pole which is wider than thereof. The proximity of an air bearing surface of the T-shaped magnetic pole is composed of a laminated film containing a magnetic material layer with a high saturated magnetic flux density which composes the magnetic pole chip and a portion of the auxiliary magnetic pole and a magnetic material layer with a low saturated magnetic flux density which composes the remaining portion of the auxiliary magnetic pole. When the front portion of the magnetic pole with the track width of 1.8 .mu.m or less is composed of a laminated film containing a magnetic material layer having a high saturated magnetic flux density and a magnetic material layer having a low saturated magnetic flux density, the thickness of the magnetic material layer having the high saturated magnetic flux density is 0.5 .
    Type: Grant
    Filed: September 10, 1998
    Date of Patent: August 22, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohichi Tateyama, Hiroaki Yoda, Tadahiko Kobayashi, Hiromi Sakata, Michiko Hara, Akio Hori, Takashi Koizumi, Tomohiko Nagata
  • Patent number: 5920447
    Abstract: A magnetic multi-head unit includes: a specific magnetic head formed so that a pair of magnetic yokes face each other on the same plane via a magnetic gap inclined by a predetermined azimuth angle; and a magnetic head which is adjacent to the specific magnetic head and which is formed so that a pair of magnetic yokes face each other on a plane different from the plane of the specific magnetic head via a magnetic gap inclined by the azimuth angle. The specific magnetic head and the adjacent magnetic head are laminated so as to form a plurality of layers while being shifted from each other in directions in which tracks on a magnetic disk extend.
    Type: Grant
    Filed: March 14, 1997
    Date of Patent: July 6, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Sakata, Hiroaki Yoda, Tomomi Funayama, Kohichi Tateyama, Tadahiko Kobayashi, Shigeru Takekado, Yoichiro Tanaka
  • Patent number: 5894384
    Abstract: The magnetic head comprises two magnetoresistance effect elements and a soft magnetic film connecting end portions of the magnetoresistance effect elements with each other. The two magnetoresistance effect elements and the soft magnetic film are arranged in series so as to form a single magnetic circuit, and a magnetic gap is provided in the side of a surface facing a magnetic medium. Magnetic flux from the magnetic medium is introduced into the magnetoresistance effect elements through the magnetic gap. An insulating material may be used to fill the magnetic gap.
    Type: Grant
    Filed: March 13, 1997
    Date of Patent: April 13, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Tadahiko Kobayashi, Hiromi Sakata, Kohichi Tateyama
  • Patent number: 5739600
    Abstract: Provided is an underwater magnetrostrictive vibration device with reduced signal attenuation and improved in efficiency and sound quality, which has been low due to external noise disturbance.
    Type: Grant
    Filed: March 19, 1996
    Date of Patent: April 14, 1998
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Kobayashi, Isao Sakai, Kiyohisa Hinohara
  • Patent number: 5601662
    Abstract: There is disclosed a method of introducing magnetic anisotropy into a magnetic material, in which a laser beam is selectively radiated on the surface of a magnetic material to locally heat it, thereby forming a pattern of boundary phases for magnetically dividing a main phase of the magnetic material into a plurality of regions, and magnetic domains of the divided main phase regions are controlled to induce magnetic anisotropy in the main phase regions.
    Type: Grant
    Filed: June 29, 1990
    Date of Patent: February 11, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takahiro Hirai, Tadahiko Kobayashi, Masashi Sahashi
  • Patent number: 5565830
    Abstract: A rare earth-cobalt supermagnetostrictive alloy having a composition represented by the general formula, in atomic fraction: R (Co.sub.1-x Fe.sub.x).sub.x, wherein 0.001.ltoreq.x.ltoreq.0.8, 0.2.ltoreq.z.ltoreq.15, and R is at least one element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu and is consisting essentially of a cubic system whose easy axis of magnetization is generally <100> or <110> oriented; or R (Co.sub.1-x Fe.sub.x).sub.x, wherein 0.001.ltoreq.x.ltoreq.0.8, 0.2.ltoreq.z.ltoreq.15, and R is at least one element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, and Lu. Such an alloy exhibits satisfactory magnetostriction in a wide range of temperatures from room temperature to liquid nitrogen temperature.
    Type: Grant
    Filed: November 29, 1993
    Date of Patent: October 15, 1996
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masashi Sahashi, Tadahiko Kobayashi
  • Patent number: 5527398
    Abstract: The magnetostriction alloys of the present invention are composed basically of Tb--Dy-iron which is partially substituted by at least one element selected from the group consisting of Y, La, Ce, Pr, Nd and Sm, and have been grown in the direction of face index <110> or contain Mn and M element (at least one metallic element selected from the group consisting of C, Mg, Al, Si, Ca, Zr, Y, Ga and B. The magnetostrictive alloy may be formed by melting the constituent materials by high frequency induction dissolution. The molten materials are cast in a heated mold having a temperature gradient. The solidified material may be further treated by hot working.
    Type: Grant
    Filed: October 22, 1993
    Date of Patent: June 18, 1996
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Tadahiko Kobayashi, Isao Sakai, Masashi Sahashi
  • Patent number: 5336337
    Abstract: The magnetostriction alloys of the present invention are composed basically of Tb-Dy-iron which is partially substituted by at least one element selected from the group consisting of Y, La, Cs, Pr, Nd and Sm, and have been grown in the direction of face index <110> or contain Mn and M element (at least one metallic element selected from the group consisting of C, Mg, Al, Si, Ca, Zr, Y, Ga and B. The magnetostrictive alloy may be formed by melting the constituent materials by high frequency induction dissolution. The molten materials are cast in a heated mold having a temperature gradient. The solidified material may be further treated by hot working.
    Type: Grant
    Filed: February 4, 1992
    Date of Patent: August 9, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Tadahiko Kobayashi, Isao Sakai, Masashi Sahashi
  • Patent number: 5260615
    Abstract: A magnetoelastic wave device comprising a substrate, a magnetostrictive film formed over the substrate, a wave generating section, a wave receiving section, and a modulation magnetic field generating section. The magnetostrictive film has an axis of easy magnetization which is substantially <uv0> axis and extends parallel to the major surfaces of the magnetostrictive film.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: November 9, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masashi Sahashi, Tadahiko Kobayashi, Tetsuhiko Mizoguchi
  • Patent number: 5223046
    Abstract: A super-magnetostrictive alloy has a high coefficient of magnetostriction and satisfactory toughness. The first type of the super-magnetostrictive alloy has a composition whose atomic ratio is expressed by (Tb.sub.x Dy.sub.1-x (Fe.sub.1-y Mn.sub.y).sub.z, where 0.35.ltoreq.x.ltoreq.0.9, 0.001.ltoreq.y.ltoreq.0.6, and 1.4.ltoreq.z.ltoreq.2.1. The second type of the super-magnetostrictive alloy has a composition whose atomic ratio is expressed by (Tb.sub.x Dy.sub.1-x (Fe.sub.1-y-w Mn.sub.y T.sub.w).sub.z, where 0.2.ltoreq.x.ltoreq.0.9, 0.05.ltoreq.y.ltoreq.0.4, 0.05.ltoreq.w.ltoreq.0.1, and 1.4.ltoreq.z.ltoreq.2.1, and where T is at least one of Co and Ni. The super-magnetostrictive alloys of both types have a Laves-type intermetallic compound phase as a main phase, and a rare earth metal phase is located between the portions having the main phase.
    Type: Grant
    Filed: March 6, 1992
    Date of Patent: June 29, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Kobayashi, Yoichi Tokai, Masashi Sahashi
  • Patent number: 5184037
    Abstract: A magnetstriction type actuator is capable of reducing an input power loss and increasing an output, which actuator is reduced in size and is applicable to a vibrator.
    Type: Grant
    Filed: February 22, 1991
    Date of Patent: February 2, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Kobayashi, Masashi Sahashi
  • Patent number: 5110376
    Abstract: A super-magnetostrictive alloy has a high coefficient of magnetostriction and satisfactory toughness. The first type of the super-magnetostrictive alloy has a composition whose atomic ratio is expressed by (Tb.sub.x Dy.sub.1-x (Fe.sub.1-y Mn.sub.y).sub.z, where 0.35.ltoreq.x.ltoreq.0.9, 0.001.ltoreq.y.ltoreq.0.6, and 1.4.ltoreq.z.ltoreq.2.1. The second type of the supermagnetostrictive alloy has a composition whose atomic ratio is expressed by (Tb.sub.x Dy.sub.1-x (Fe.sub.1-y-w Mn.sub.y T.sub.w).sub.z, where 0.2.ltoreq.x.ltoreq.0.9, 0.05.ltoreq.y.ltoreq.0.4, 0.05.ltoreq.w.ltoreq.0.1, and 1.4.ltoreq.z.ltoreq.2.1, and where T is at least one of Co and Ni. The super-magnetostrictive alloys of both types have a Laves-type intermetallic compound phase as a main phase, and a rare earth metal phase is located between the portions having the main phase.
    Type: Grant
    Filed: March 18, 1991
    Date of Patent: May 5, 1992
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Kobayashi, Yoichi Tokai, Masashi Sahashi
  • Patent number: RE34039
    Abstract: A torque sensor of noncontact type, by which can be stably measured the torque of a shaft with a sufficient S/N ratio under the influence of external magnetic noise, such as an induction magnetic flux which is produced in an induction motor, and which can be readily disposed in a comparatively small space. When provided on an induction motor, the torque sensor is mounted on the induction motor in noncontacting relationship. The torque sensor detects the torque of the shaft and includes a pair of magnetic material members provided on respective circumferential portions of the peripheral surface of a shaft. A pair of magnetic detectors are disposed at opposite locations at which external magnetic fields having opposite phase exist. The detectors detect the variation of the magnetic characteristics of the magnetic materials, and a signal processing circuit produces a mean value of output signals obtained from the magnetic detectors.
    Type: Grant
    Filed: January 27, 1989
    Date of Patent: August 25, 1992
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadahiko Kobayashi, Masashi Sahashi, Koichiro Inomata, Tomokazu Domon