Patents by Inventor Yohji Maruyama

Yohji Maruyama 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: 20030103294
    Abstract: Magnetic disk apparatus includes an electric wiring capable of satisfying an electric condition under which high frequency recording higher than or equal to 200 MHz, a magnetic head having at least a recording device to a magnetic recording medium, and also the electric wiring corresponding to a recording current supplying device to this magnetic head are formed on a suspension member for mechanically suspending the magnetic head, the recording current being supplied to a magnetic head recording device by employing such electric wiring, the characteristic impedance of which is higher than a maximum impedance of the magnetic head recording device.
    Type: Application
    Filed: December 13, 2002
    Publication date: June 5, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Publication number: 20030095357
    Abstract: A thin film magnetic head includes a lower magnetic pole, an upper magnetic pole provided so as to face the lower magnetic pole, and a magnetic gap layer provided between the lower magnetic pole and the upper magnetic pole. The upper magnetic pole constitutes a first magnetic layer formed on a side facing the magnetic gap layer by means of sputtering and a second magnetic layer formed on the first magnetic layer by means of plating, in which the saturation magnetic flux density of the first magnetic layer is set higher than that of the second magnetic layer. The thin film magnetic head composed as above is capable of generating a stronger magnetic field owing to its stably-formed magnetic core, thereby recording on a high-coercivity medium and high-density recording are made possible.
    Type: Application
    Filed: August 14, 2002
    Publication date: May 22, 2003
    Inventors: Kazue Kudo, Yasuyuki Okada, Moriaki Fuyama, Yohji Maruyama, Gen Oikawa
  • Patent number: 6560168
    Abstract: An information recording apparatus using a recording medium which holds information by reversed magnetic domains on a perpendicular magnetic recording film includes an irradiation unit for applying electromagnetic energy or light onto the recording medium, and a magnetic flux detection unit for detecting magnetic leakage flux emerging from the recording medium, the magnetic flux detection unit being disposed on the same side as the irradiation unit with respect to the recording medium. As a result, both side recording of the recording medium can be conducted.
    Type: Grant
    Filed: December 12, 2000
    Date of Patent: May 6, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Hideki Saga, Hiroaki Nemoto, Hirofumi Sukeda, Masahiko Takahashi, Kimio Nakamura, Yohji Maruyama, Hiroshi Ide, Takehiko Hamaguchi
  • Patent number: 6549355
    Abstract: A recording equalizer for correcting a write timing of magnetic information when the magnetic information is recorded with a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after the recording object bit and a calculator for calculating a precompensation parameter using the bits stored in the buffer. The calculator calculates the precompensation parameter of the recording object bit by linearly adding influence of a transition existing at a two-previous bit of the recording object bit, influences of a transition at a one-previous bit of the recording object bit and influences of a transition existing at one-following bit of the recording object bit and further adding an offset. The offset is determined to a value such that a write timing of the magnetic information is corrected always in a delaying direction.
    Type: Grant
    Filed: August 30, 2002
    Date of Patent: April 15, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Patent number: 6530141
    Abstract: A method of forming a thin film magnetic head, including forming a first magnetic layer, forming a second magnetic layer as a magnetic flux passage in combination with the first magnetic layer, and forming a laminate structure body between the first magnetic layer and the second magnetic layer. The forming of the laminate structure body includes forming a third magnetic layer, a fourth magnetic layer and a non-magnetic conductive layer between the third magnetic layer and the fourth magnetic layer, projecting the laminate structure body more toward an air bearing surface than a projection of the first magnetic layer and the second magnetic layer toward the air bearing surface, and providing the laminate structure body with a width which is smaller than a width of the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: June 14, 2001
    Date of Patent: March 11, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Matahiro Komuro, Tomohiro Okada, Moriaki Fuyama, Tetsuo Ito, Hiroshi Fukui, Yohji Maruyama, Miki Hara, Hisashi Takano
  • Patent number: 6529348
    Abstract: The magnetic disk apparatus includes an electric wiring capable of satisfying an electric condition under which high frequency recording higher than or equal to 200 MHz can be accomplished. A magnetic head having at least a recording device for recording to a magnetic recording medium is provided as well as an electric wiring corresponding to a recording current supplying device for this magnetic head are formed on a suspension member for mechanically suspending the magnetic head. The recording current is supplied to a magnetic head recording device by employing such electric wiring, the characteristic impedance of which is higher than a maximum impedance of the magnetic head recording device.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: March 4, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Publication number: 20030026024
    Abstract: A recording equalizer for correcting a write timing of magnetic information when the magnetic information is recorded with a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after the recording object bit and a calculator for calculating a precompensation parameter using the bits stored in the buffer. The calculator calculates the preconpensation parameter of the recording object bit by linearly adding influence of a transition existing at a two-previous bit of the recording object bit, influences of a transition at a one-previous bit of the recording object bit and influences of a transition existing at one-following bit of the recording object bit and further adding an offset. The offset is determined to a value such that a write timing of the magnetic information is corrected always in a delaying direction.
    Type: Application
    Filed: August 30, 2002
    Publication date: February 6, 2003
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Patent number: 6487031
    Abstract: A recording equalizer for correcting a write timing of magnetic information when the magnetic information is recorded with a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after the recording object bit and a calculator for calculating a precompensation parameter using the bits stored in the buffer. The calculator calculates the preconpensation parameter of the recording object bit by linearly adding influence of a transition existing at a two-previous bit of the recording object bit, influences of a transition at a one-previous bit of the recording object bit and influences of a transition existing at one-following bit of the recording object bit and further adding an offset. The offset is determined to a value such that a write timing of the magnetic information is corrected always in a delaying direction.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: November 26, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Publication number: 20020114093
    Abstract: A recording equalizer for correcting a write timing of magnetic information when the magnetic information is recorded with a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after the recording object bit and a calculator for calculating a precompensation parameter using the bits stored in the buffer. The calculator calculates the preconpensation parameter of the recording object bit by linearly adding influence of a transition existing at a two-previous bit of the recording object bit, influences of a transition at a one-previous bit of the recording object bit and influences of a transition existing at one-following bit of the recording object bit and further adding an offset. The offset is determined to a value such that a write timing of the magnetic information is corrected always in a delaying direction.
    Type: Application
    Filed: February 22, 2002
    Publication date: August 22, 2002
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Publication number: 20020109944
    Abstract: Magnetic disk apparatus includes an electric wiring capable of satisfying an electric condition under which high frequency recording higher than or equal to 200 MHz, a magnetic head having at least a recording device to a magnetic recording medium, and also the electric wiring corresponding to a recording current supplying device to this magnetic head are formed on a suspension member for mechanically suspending the magnetic head, the recording current being supplied to a magnetic head recording device by employing such electric wiring, the characteristic impedance of which is higher than a maximum impedance of the magnetic head recording device.
    Type: Application
    Filed: April 22, 2002
    Publication date: August 15, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Patent number: 6404594
    Abstract: The magnetic disk apparatus includes an electric wiring capable of satisfying an electric condition under which high frequency recording higher than or equal to 200 MHz can be accomplished. A magnetic head having at least a recording device for recording to a magnetic recording medium is provided as well as an electric wiring corresponding to a recording current supplying device for this magnetic head are formed on a suspension member for mechanically suspending the magnetic head. The recording current is supplied to a magnetic head recording device by employing such electric wiring, the characteristic impedance of which is higher than a maximum impedance of the magnetic head recording device.
    Type: Grant
    Filed: March 10, 2000
    Date of Patent: June 11, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Patent number: 6356402
    Abstract: A recording equalizer for correcting a write timing of magnetic information when the magnetic information is recorded with a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after the recording object bit and a calculator for calculating a precompensation parameter using the bits stored in the buffer. The calculator calculates the preconpensation parameter of the recording object bit by linearly adding influence of a transition existing at a two-previous bit of the recording object bit, influences of a transition at a one-previous bit of the recording object bit and influences of a transition existing at one-following bit of the recording object bit and further adding an offset. The offset is determined to a value such that a write timing of the magnetic information is corrected always in a delaying direction.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: March 12, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Patent number: 6349008
    Abstract: A magnetic recording medium wherein, when the axis of easy magnetization of the magnetic recording medium for magnetically recording information by means of a magnetic head is projected onto a surface of the magnetic recording medium, the axis projected onto the surface of the magnetic recording medium exists so as to be unidirectionally inclined with respect to the direction of a track on which information is to be recorded, whereby, by using the magnetic recording medium, there can be provided a magnetic head and a magnetic read-write apparatus greatly improved in longitudinal recording density.
    Type: Grant
    Filed: October 21, 1998
    Date of Patent: February 19, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Takanobu Takayama, Kiwamu Tanahashi, Kazuetsu Yoshida, Mikio Suzuki, Yoshiyuki Hirayama, Masaaki Futamoto, Yohji Maruyama
  • Publication number: 20020018318
    Abstract: In a convention inductive head, since a large magnetic field is leaked from the end of the magnetic pole end of an upper magnetic core, at recording the recording magnetic field is applied to a recording media in a region larger than a desired track width, thereby damaging the adjacent information.
    Type: Application
    Filed: March 20, 2001
    Publication date: February 14, 2002
    Inventors: Shunichi Narumi, Hiroyuki Hoshiya, Yohji Maruyama
  • Patent number: 6327112
    Abstract: An information storage apparatus has a disk medium setting data recording areas along a plurality of tracks concentrically arranged, a head for recording and reproducing data on tracks of the disk medium, an actuator for moving the head to a desired track among the plurality of tracks. Also included is an electric circuit for controlling recording and reproducing in response to detecting the distance from a recorded magnetization pattern on an adjacent track in the radial direction by detecting previously recorded signals on adjacent tracks while data recording. Even if the track density is increased, the upper limit of a threshold value of a function for preventing off-track recording of the information storage apparatus can be increased and a high track density of the information storage apparatus can be easily realized.
    Type: Grant
    Filed: January 5, 1999
    Date of Patent: December 4, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Ide, Futoshi Tomiyama, Yasutaka Nishida, Takehiko Hamaguchi, Hisashi Takano, Yohji Maruyama, Atsushi Nakamura, Hideki Sawaguchi
  • Publication number: 20010027603
    Abstract: A method of forming a thin film magnetic head, including forming a first magnetic layer, forming a second magnetic layer as a magnetic flux passage in combination with the first magnetic layer, and forming a laminate structure body between the first magnetic layer and the second magnetic layer. The forming of the laminate structure body includes forming a third magnetic layer, a fourth magnetic layer and a non-magnetic conductive layer between the third magnetic layer and the fourth magnetic layer, projecting the laminate structure body more toward an air bearing surface than a projection of the first magnetic layer and the second magnetic layer toward the air bearing surface, and providing the laminate structure body with a width which is smaller than a width of the first magnetic layer and the second magnetic layer.
    Type: Application
    Filed: June 14, 2001
    Publication date: October 11, 2001
    Inventors: Matahiro Komuro, Tomohiro Okada, Moriaki Fuyama, Tetsuo Ito, Hiroshi Fukui, Yohji Maruyama, Miki Hara, Hisashi Takano
  • Publication number: 20010007516
    Abstract: A recording equalizer for correcting a write timing of magnetic information when the magnetic information is recorded with a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after the recording object bit and a calculator for calculating a precompensation parameter using the bits stored in the buffer. The calculator calculates the preconpensation parameter of the recording object bit by linearly adding influence of a transition existing at a two-previous bit of the recording object bit, influences of a transition at a one-previous bit of the recording object bit and influences of a transition existing at one-following bit of the recording object bit and further adding an offset. The offset is determined to a value such that a write timing of the magnetic information is corrected always in a delaying direction.
    Type: Application
    Filed: February 23, 2001
    Publication date: July 12, 2001
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Patent number: 6212024
    Abstract: A recording equalizer for precompensating of a write timing of magnetic information when the magnetic information is recorded by a magnetic recording head on a magnetic recording medium, includes a buffer for storing a recording object bit and bits before and after said recording object bit, and a calculator for calculating and outputting a precompensation parameter using the bits stored in the buffer by adding an offset C, having a value such as to always delay the write timing of the magnetic information, to an amount of shift determined using the bits stored in the buffer and the head velocity relative to the medium.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: April 3, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Masukazu Igarashi, Yohji Maruyama, Kazuetsu Yoshida, Ikuo Saitoh
  • Patent number: 6104574
    Abstract: A leaking magnetic flux from a taper portion is canceled by utilizing an eddy current loss by using a magnetic head having a structure wherein at least a part of a magnetic pole constituting a magnetic path through a recording gap is sandwiched by conductive materials with respect to a track width direction, and a write blur quantity can be thus reduced. Further, magnetic saturation can be prevented by limiting a volume decrease at the distal end portion of the magnetic pole when the track width is reduced. Accordingly, the present invention can prevent magnetic saturation of the distal end portion of the magnetic pole resulting from the reduction of the width of the track of the recording head, can accomplish narrow-track recording by the recording head to a recording medium having high-coercive force and can reduce write blur.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: August 15, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hisashi Takano, Yohji Maruyama, Makoto Aihara, Takashi Kawabe, Moriaki Fuyama
  • Patent number: 6091582
    Abstract: A thin film magnetic head is providing for recording with less blur having a high recording magnetic field, for use in a recording/reproduction separation type magnetic head and a magnetic recording/reproducing apparatus. The thin film magnetic head, in which a gap film of a recording head and a magnetic film in contact with the gap film have the same track width, includes an upper magnetic film of the recording head and an upper shield film of a magnetic resistive film, each having a width wider than the track width, and a cross section parallel to the air bearing surface of the upper magnetic film is reduced at a position less than a gap depth from the air bearing surface.
    Type: Grant
    Filed: March 27, 1998
    Date of Patent: July 18, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Matahiro Komuro, Tomohiro Okada, Moriaki Fuyama, Tetsuo Ito, Hiroshi Fukui, Yohji Maruyama, Miki Hara, Hisashi Takano