Patents by Inventor Kyo Akagi

Kyo Akagi 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).

  • Publication number: 20020018325
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer comprised of an insulating material, a semicondcutor or an antiferromagnetic material against said magnetic layers, and the magnetoresistance effect element has terminals formed with at least on the opposite magnetic layers, respectively, so that a current is sure to be flowed in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Application
    Filed: August 20, 2001
    Publication date: February 14, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 6278593
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semicondutor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: December 21, 1999
    Date of Patent: August 21, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 6130797
    Abstract: Virtual tracks are set so that the rotation center of a magnetic recording medium or the vicinity of the rotation center coincides with the track center of the data information, and positioning servo control is performed. Thus, since it is not necessary to faithfully follow the track center line specified by the servo information that is previously recorded on the magnetic recording medium or magnetooptical recording medium, a vibration is not easily caused in synchronism with the rotation. Therefore, when the rotation center and the pattern center are deviated from each other, since a vibration is not caused in synchronism with the rotation, the magnetic head of the magnetic recorder or the magnetooptical head of the magnetooptical recorder is able to follow tracks with higher precision. Accordingly, the recording density can be increased.
    Type: Grant
    Filed: September 16, 1997
    Date of Patent: October 10, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Kyo Akagi, Yoshihiro Shiroishi, Reijiro Tsuchiya, Takehiko Hamaguchi, Masuo Umemoto, Mikio Suzuki, Takashi Kawabe, Katsuro Watanabe, Kiyoshi Matsumoto, Atsushi Saito, Kouichirou Wakabayashi, Yosuke Hamada
  • Patent number: 6011674
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-denisity recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: April 2, 1996
    Date of Patent: January 4, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 5786952
    Abstract: A magnetic digital storage method and system which can improve a recording density and can reduce a cross-talk upon reproducing. An inputted high-speed digital signal is converted to a plurality of low-speed digital signal sequences by a recording circuit and each of the low-speed signal sequence is recorded onto a plurality of adjacent recorded tracks of a recording medium by integrated parallel recording heads. One servo signal is commonly recorded to the plurality of recorded tracks. Further, when recording the digital signal to the adjacent recorded tracks of the recording medium, a delay of a signal that is applied to each recording head is adjusted such that the phases of magnetic transition points given by the recording signal in the adjacent recorded tracks are not identical in the circumferential direction.
    Type: Grant
    Filed: November 22, 1995
    Date of Patent: July 28, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Masuo Umemoto, Yoshihiro Shiroishi, Reijiro Tsuchiya, Kyo Akagi, Takehiko Hamaguchi, Takashi Kawabe, Atsushi Saito, Kouichirou Wakabayashi
  • Patent number: 5766718
    Abstract: It is disclosed that a longitudinal magnetic recording medium and apparatus has recording sections having longitudinal magnetic films magnetically isolated in a recording direction. The magnetically isolated recording sections can record a single bit each so that the longitudinal magnetic recording medium can remove the irregular domain boundary of its own caused on boundaries of magnetization reversals in the recording direction. This can improve the signal-to-media noise ratio to a great extent in writing and reading.
    Type: Grant
    Filed: January 31, 1994
    Date of Patent: June 16, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Yoshibumi Matsuda, Masaaki Futamoto, Fumio Kugiya, Yoshinori Miyamura, Takeshi Nakano, Hisashi Takano, Kyo Akagi, Mikio Suzuki, Yasuhide Ouchi
  • Patent number: 5736235
    Abstract: A magnetic recording medium, its fabrication method, and a magnetic recording apparatus in which both saturation induction and coercive force of a magnetic film is made high as they are near a surface of the recording medium. A high density information recording can be made higher than 50 kFCI in linear recording density even for spacing around 0.2 .mu.m.
    Type: Grant
    Filed: August 6, 1991
    Date of Patent: April 7, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Yoshibumi Matsuda, Masaaki Futamoto, Yoshinori Miyamura, Tokuho Takagaki, Hisashi Takano, Fumio Kugiya, Takeshi Nakao, Kyo Akagi, Mikio Suzuki, Hirotsugu Fukuoka, Takayuki Munemoto
  • Patent number: 5726837
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: October 24, 1994
    Date of Patent: March 10, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 5606472
    Abstract: A disk unit has a recording medium disk; a head for reading and writing information on said disk; a first actuator for moving said head relative to said disk, said first actuator having no bearing structure; a second actuator for rotating said disk, said second actuator having no bearing structure; and a housing for housing said disk, said head, said first actuator and said second actuator.
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: February 25, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Kyo Akagi, Yasuhiro Kato, Masaaki Matsumoto, Akira Iida, Yong-kweon Kim
  • Patent number: 5568331
    Abstract: A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein a data signal is recorded in the data recording layer of said recording medium, a servo signal is recorded in the servo signal recording layer located below said data signal recording layer, said data signal is read out using a data magnetic head whereas said servo signal is read out using a servo magnetic head, and the frequency of said servo signal is within the range of the gap-null frequency of said data magnetic head whereas the frequency of said data signal is within the range of the gap-null frequency of said servo magnetic head, and said magnetic head is positioned on the data track on the basis of said servo signal.
    Type: Grant
    Filed: October 25, 1990
    Date of Patent: October 22, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Kyo Akagi, Masaaki Futamoto, Fumio Kugiya, Yoshinori Miyamura, Hisashi Takano, Yoshibumi Matsuda, Mikio Suzuki, Takeshi Nakao, Takayuki Munemoto, Hirotsugu Fukuoka, Makoto Aihara, Tokuho Takagaki, Hajime Aoi, Yosuke Seo
  • Patent number: 5557486
    Abstract: A disk unit has a recording medium disk; a head for reading and writing information on said disk; a first actuator for moving said head relative to said disk, said first actuator having no bearing structure; a second actuator for rotating said disk, said second actuator having no bearing structure; and a housing for housing said disk, said head, said first actuator and said second actuator.
    Type: Grant
    Filed: December 2, 1993
    Date of Patent: September 17, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Kyo Akagi, Yasuhiro Kato, Masaaki Matsumoto, Akira Iida, Yong-kweon Kim
  • Patent number: 5390061
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: June 5, 1991
    Date of Patent: February 14, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 5325244
    Abstract: A magnetic recording data storage system includes a magnetic recording medium having pits formed therein, the pits defining recording tracks on the magnetic recording medium and being arranged in a staggered manner relative to respective center lines of the recording tracks, a magnetic head including an inductive element for recording data on the recording tracks and a magnetoresistive element for reproducing data from the recording tracks, one of (1) a unit for magnetically producing a signal from the pits, and (2) an optical unit for optically producing a signal from the pits, the optical unit including a laser for illuminating the pits, servo means for positioning the head on the recording tracks based on the signal produced from the pits, the servo means including a dual-stage actuator including a rough movement portion and a fine movement portion.
    Type: Grant
    Filed: February 28, 1992
    Date of Patent: June 28, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Hisashi Takano, Kyo Akagi, Mikio Suzuki, Yoshibumi Matsuda, Takeshi Nakao, Yoshinori Miyamura, Fumio Kugiya, Masaaki Futamoto, Hideki Sawaguchi, Nobuyuki Inaba, Takayuki Munemoto, Kenji Mori, Hirotsugu Fukuoka, Tokuho Takagaki
  • Patent number: 5253232
    Abstract: A magneto-optical recording apparatus including a magnetic head applying a magnetic field to a magneto-optical recording medium in a region wider than a minimum bit record area thereby forming a magnetic field region, a beam source and an optical system forming on the magneto-optical recording medium a laser beam spot defining the minimum bit record area, a modulation unit for modulating at least one of the magnetic field and the laser beam thereby forming the laser beam spot within the range of the magnetic field region, and a mechanical unit for moving the magnetic field region and the laser beam spot relative to each other on the magneto-optical recording medium while the modulation unit is under operation, the magnetic head being floated to be spaced apart from the surface of the magneto-optical recording medium by a distance not smaller than 10 .mu.m while the mechanical unit is under operation.
    Type: Grant
    Filed: March 30, 1990
    Date of Patent: October 12, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Kyo Akagi, Takeshi Nakao, Masahiro Ojima
  • Patent number: 5093822
    Abstract: A high-density magnetic recording and optical reproducing apparatus for magneto-optically reproducing information magnetically recorded on information tracks on a recording medium, the apparatus comprising two laser beam sources emitting laser beams having different wavelengths respectively, an optical system for directing the laser beams from the two laser beam sources toward and onto the recording medium so as to irradiate the recording medium with laser beam spots partly overlapping each other, two photo detectors detecting the laser beams reflected from the surface of the recording medium, and a differential amplifier detecting the difference between the output signals of the two photo detectors thereby generating the differential signal as a reproduced output.
    Type: Grant
    Filed: June 4, 1990
    Date of Patent: March 3, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Fumio Kugiya, Mikio Suzuki, Kyo Akagi, Takeshi Nakao, Masaaki Futamoto, Yoshinori Miyamura, Hisashi Takano, Yoshibumi Matsuda