Patents by Inventor Hiroshi Youda

Hiroshi Youda 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: 4700252
    Abstract: A magnetic thin film head used for perpendicular magnetic recording and reproduction. The head includes a magneto-resistive element and a flux guide made of high permeability thin film whose one end portion faces a perpendicular magnetic recording medium. The magnetic flux produced by the magnetization signal on the perpendicular magnetic recording medium is led to the magneto-resistive element through the flux guide. The head also includes electrodes for supplying an electric current londitudinally to the magneto-resistive element, and high permeability members for introducing the magnetic flux through the magneto-resistive element back to the perpendicular magnetic recording medium. The head further includes a exciting means for the flux guide.
    Type: Grant
    Filed: October 15, 1984
    Date of Patent: October 13, 1987
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroaki Muraoka, Seishi Sasaki, Ken Takahashi, Hiroshi Youda
  • Patent number: 4663683
    Abstract: In a magnetic head which utilizes the magnetoresistive effect of a ferromagnetic thin film, it is possible to realize a magnetoresistive effect type thin film magnetic head with favorable secondary distortion characteristics by forming on at least one surface of the ferromagnetic thin film, a grating forming an angle larger than 60.degree. and smaller than 80.degree. with respect to the direction of the electric current flowing through the thin film. By setting the grating into more than two different directions, a magnetic head capable of functioning at a still smaller distortion is presented.
    Type: Grant
    Filed: July 3, 1984
    Date of Patent: May 5, 1987
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Youda, Nobuyuki Kaminaka, Satoru Mitani
  • Patent number: 4654739
    Abstract: A thin film magnetic head for reproducing perpendicular magnetization comprising an operative surface disposed to face a recording medium, a thin film magnetization detection portion including a magneto-resistive element perpendicular to the operative surface of the head with one side edge of the magnetization detection portion being exposed to the operative surface, ferromagnetic material with one end thereof being magnetically coupled to the side edge portion of the thin film magnetization detection portion most distant from said operative surface and with the other end thereof being exposed to the operative surface, and a non-magnetic material disposed in an area defined by the thin film magnetization detection portion, the ferromagnetic material and the operative surface, wherein the distance between the thin film magnetization detection portion and the ferromagnetic material at said operative surface is at least five times the distance between the end of the ferromagnetic material magnetically coupled to
    Type: Grant
    Filed: December 31, 1984
    Date of Patent: March 31, 1987
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Ken Takahashi, Hiroshi Youda, Seishi Sasaki, Kenji Kanai
  • Patent number: 4425701
    Abstract: A method for making magnetic recording heads suitable for mass production with high accuracy.The track width tw or w of the head core is defined by a photolithographic etching method.First, larger grooves are formed by mechanical machining or electrolytic etching to form an outline of the pole piece parts, and then further smaller and shallower grooves are formed with very high accuracy by an etching process, such as electrolytic etching, sputter etching or ion etching at the edges of the first grooves. Thus, the track width of the head core is accurately determined by means of a photolithographic process.
    Type: Grant
    Filed: October 9, 1981
    Date of Patent: January 17, 1984
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Ken Takahashi, Hiroshi Youda