Patents by Inventor Shunichiro Kuwatsuka

Shunichiro Kuwatsuka 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: 5349745
    Abstract: A method of fabricating a thin-film magnetic in which a mask pattern in etching a bottom pole is formed of first and second mask films in this order when viewed from the bottom pole, the first mask film is used for defining, by self-alignment, the length of that portion of the side edge of a top pole which is nearly perpendicular to a magnetic gap, the second mask film makes it possible to etch the bottom pole with high dimensional accuracy, a non-magnetic film is formed on the mask pattern having the bottom pole thereunder and the exposed region of a substrate, and the top pole is formed after the mask pattern has been exposed and removed.
    Type: Grant
    Filed: June 1, 1993
    Date of Patent: September 27, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Kawabe, Eiji Ashida, Moriaki Fuyama, Tadayuki Iwakura, Hiroshi Fukui, Yoshikazu Tsuji, Shunichiro Kuwatsuka, Harunobu Saito, Yoshiki Hagiwara, Issei Takemoto, Masayasu Fujisawa
  • Patent number: 5296979
    Abstract: A magnetic disc apparatus includes a magnetic disc for recording information; a thin film magnetic head including a magnetic pole structure having an upper magnetic pole tip and a lower magnetic pole tip arranged to provide a magnetic gap at respective end portions thereof for writing and reading information in and from the magnetic disc; a device for rotating the magnetic disc; and a device for positioning the thin film magnetic head; the upper and lower magnetic pole tips having different contours at the respective end portions as viewed from a side confronting the magnetic disc wherein the difference (.DELTA.CW in .mu.m) in the width, along the magnetic gap, of the upper magnetic pole tip and the width, along the magnetic gap, of the lower magnetic pole tip satisfies the relation0<.DELTA.CW.ltoreq.5000/Trfor the magnetic disc having a track density Tr of 1800 or more tracks per inch.
    Type: Grant
    Filed: October 19, 1992
    Date of Patent: March 22, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Kawabe, Moriaki Fuyama, Shinji Narishige, Masatoshi Tsuchiya, Eiji Ashida, Makoto Morijiri, Hideki Yamazaki, Yutaka Sugita, Hiroshi Fukui, Tadayuki Iwakura, Makoto Aihara, Makoto Saito, Shunichiro Kuwatsuka, Hiroshi Ikeda, Yokuo Saitoh
  • Patent number: 5245493
    Abstract: A magnetic head for reading from and/or writing to a magnetic information storage medium has a substrate on which a plurality of thin films are formed in sequence. The films provide a magnetic circuit having a magnetic gap, a bottom pole piece and a top pole piece overlying said bottom pole piece. The top pole piece is formed as a tip portion adjoining the magnetic gap and a rear portion which makes magnetic contact with the tip portion. The rear portion is formed in the sequence after the tip portion. To ensure accurate thickness and width of the tip portion, a non-magnetic protective film is formed on the tip portion after the tip portion is formed and before the rear portion is formed.
    Type: Grant
    Filed: March 20, 1990
    Date of Patent: September 14, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Kawabe, Moriaki Fuyama, Shinji Narishige, Eizi Ashida, Makoto Morijiri, Masanori Tanabe, Hiroshi Fukui, Yutaka Sugita, Hiroshi Ikeda, Masaaki Hayashi, Kazuo Nakagoshi, Kanji Kawakami, Yokuo Saitoh, Shunichiro Kuwatsuka
  • Patent number: 5241440
    Abstract: A thin film magnetic head including conductor coils, a plurality of insulating layers to interpose and insulate the conductor coils and a magnetic gap layer between upper and lower magnetic cores, in which another insulating layer is provided on a stepped region formed by end faces of the plurality of insulating layers.
    Type: Grant
    Filed: June 29, 1992
    Date of Patent: August 31, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Eizi Ashida, Moriaki Fuyama, Hideki Yamazaki, Shinji Narishige, Makoto Morijiri, Takashi Kawabe, Shunichiro Kuwatsuka, Saburo Suzuki, Eisei Togawa
  • Patent number: 4841624
    Abstract: A method of producing a thin film magnetic head by successively depositing on a substrate a first magnetic material, a gap material, an electrically conductive material consisting of a coil, an insulating film, a second magnetic material and a protecting film, wherein the improvement comprises a step for forming a recessed portion in the insulating film at a portion corresponding to a gap portion on the air bearing surface side, the bottom surface of said recessed portion serving as an exposed portion on the upper surface of the gap material and the side surfaces of said recessed portion being tapered, a step for forming a recessed portion in the gap material by etching using the insulating film with the recessed portion as a mask and making the thickness thereof equal to the gap length, and a step for depositing a second magnetic material on the whole surface, so that the recessed portion formed in the gap material will have a rectangular shape with its one side being equal to a gap depth and its another sid
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: June 27, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Eisei Togawa, Saburo Suzuki, Kenji Sugimoto, Shunichiro Kuwatsuka
  • Patent number: 4841402
    Abstract: A thin film magnetic head having two conductor layers provided within a magnetic circuit constituted by a first and a second magnetic member. The magnetic circuit has, at the side to which a recording medium is opposed, a portion where the first and second magnetic members are opposed to each other over a length substantially equal to a gap depth, intervening a non-magnetic gap member therebetween, and a portion ahead thereof where they are connected with each other. The edge of the gap member constitutes an aperture of the magnetic circuit. The thin film magnetic head arranged as above permits a high density recording without reducing its production yield.
    Type: Grant
    Filed: January 20, 1987
    Date of Patent: June 20, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Tadashi Imanaka, Masayuki Takagi, Eisei Togawa, Harunobu Saito, Sadanori Nagaike, Masaki Ohura, Saburo Suzuki, Tetsuo Kobayashi, Shunichiro Kuwatsuka
  • Patent number: 4824731
    Abstract: A thin film magnetic head of which the insulation layer is made of a polyimide resin obtained by heat-curing a polyimide precursor represented by the following general formula (I) or (II) or a mixture thereof not only has excellent characteristics with respect to the insulation layer, i.e. satisfactory flatness, high glass transition temperature and excellent adhesiveness but also is free from film defects, i.e., exhibits high reliability: ##STR1## wherein R is, e.g., ##STR2## Ar.sup.1 is, e.g., ##STR3## Ar.sup.2 is, e.g. ##STR4## n is an integer of 1 to 100, and m is an integer of 10 to 500.
    Type: Grant
    Filed: January 28, 1988
    Date of Patent: April 25, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Haruhiko Matsuyama, Fusaji Shoji, Shunichiro Kuwatsuka, Kenji Sugimoto
  • Patent number: 4550353
    Abstract: A thin-film magnetic head having a magnetic core of double step structure and a method of fabricating it. A first magnetic core is formed on a substrate, which has a predetermined thickness at a pole chip region thereof and a thickness larger than the predetermined thickness at a back region thereof; a magnetic gap is formed thereon, a conductor coil is formed on the magnetic gap, which is encircled by an inter-layer, insulating film; a first magnetic film is formed thereon, which constitutes one layer of a second magnetic core and is connected with the first magnetic core at the back region; and a second magnetic film is formed thereon through an inorganic insulating film, which constitutes another layer of the second magnetic core and is removed at the pole chip region. When the second magnetic film is removed, the inorganic insulating film serves to protect the first magnetic film, and hence the thickness of the first magnetic film is maintained unvaried.
    Type: Grant
    Filed: December 7, 1983
    Date of Patent: October 29, 1985
    Assignee: Computer Basic Technology Research
    Inventors: Osamu Hirai, Tetsuo Kobayashi, Shunichiro Kuwatsuka, Saburo Suzuki