Patents by Inventor Hisashi Takano

Hisashi Takano 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: 7016156
    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: Grant
    Filed: October 12, 2004
    Date of Patent: March 21, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Patent number: 7006326
    Abstract: A magnetic head for perpendicular recording without writing from the lateral sides of a mains pole and without erasing data on adjacent tracks. A magnetic disk storage apparatus using the magnetic head. The lateral side of the main pole of a magnetic head for perpendicular recording may have an inverted tapered shape obtained by forming a groove as a track portion to an inorganic insulating layer and then forming a magnetic layer and then flattening the upper surface. A leading edge, a trailing edge, or both lateral edges of the magnetic head may be tapered. The taper may be either smooth and linear or curved in profile.
    Type: Grant
    Filed: February 2, 2004
    Date of Patent: February 28, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Tomohiro Okada, Yasutaka Nishida, Masafumi Michizuki, Hisashi Takano
  • Publication number: 20050237651
    Abstract: A magnetic recording/reproducing apparatus includes a partial-response equalization circuit having frequency characteristic of cutting off low-frequency signal components inclusive of DC components; and a maximum-likelihood decoder, in which a reproduced signal outputted from the reproducing head is processed by the partial-response equalization circuit and then inputted into the maximum-likelihood decoder to be data-reproduced, thereby reducing a noise and distortion on the reproduced signal and reducing a data detection error rate.
    Type: Application
    Filed: June 24, 2005
    Publication date: October 27, 2005
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Toru Matsushita
  • Patent number: 6912100
    Abstract: A magnetic recording/reproducing apparatus includes a partial-response equalization circuit having frequency characteristic of cutting off low-frequency signal components inclusive of DC components; and a maximum-likelihood decoder, in which a reproduced signal outputted from the reproducing head is processed by the partial-response equalization circuit and then inputted into the maximum-likelihood decoder to be data-reproduced, thereby reducing a noise and distortion on the reproduced signal and reducing a data detection error rate.
    Type: Grant
    Filed: April 14, 2004
    Date of Patent: June 28, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Toru Matsushita
  • Patent number: 6906889
    Abstract: A magnetic disk drive has a low power consumption state in which the spindle motor is stopped for reducing the average power consumption when no read or write commands have been received. When a read or write command is received, the spindle motor is started. The time it takes to complete a read command is shorter than that for a write command as measured from the receipt of the read command or write command with the spindle motor stopped in the low power consumption state.
    Type: Grant
    Filed: August 14, 2002
    Date of Patent: June 14, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Takehiko Hamaguchi, Hisashi Takano, Futoshi Tomiyama, Toru Matsushita
  • Patent number: 6894874
    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: Grant
    Filed: July 23, 2003
    Date of Patent: May 17, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Patent number: 6879460
    Abstract: A magnetic recording disk drive can prevent the deterioration of the head off-track characteristics and the reduction of the drive performance even when an erase band asymmetry resulting from a skew angle exists. A write inhibit slice value for an inner peripheral side offset is made smaller than a write inhibit slice value for an outer peripheral side offset at a position where an erase band on the inner peripheral side is greater than an erase band on the outer peripheral side, so that the adjacent track on the outer peripheral side cannot easily erase a data track. On the contrary, the inner periphery and the outer periphery are paraphrased at a position where the erase band on the outer peripheral side is greater than the erase band on the inner peripheral side.
    Type: Grant
    Filed: October 9, 2003
    Date of Patent: April 12, 2005
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Futoshi Tomiyama, Takehiko Hamaguchi, Toru Matsushita, Hideki Zaitsu, Reijiro Tsuchiya, Hisashi Takano
  • Publication number: 20050063097
    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: October 12, 2004
    Publication date: March 24, 2005
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Publication number: 20050036226
    Abstract: A hard disk drive and magnetic medium including a servo area, a data area divided into a plurality of sector blocks and at least one micro-servo area disposed between two sector blocks. There may be a micro-servo area immediately preceding each of the plurality of sector blocks. The micro-servo areas include an address mark and a track parity check code that allow the detection of an external shock that causes the recording (write) head to skip to an adjacent track in the hard disk medium. The micro-servo area is smaller than the servo areas, and various numbers of different track parity check codes can be used for different resolution of shock detection. An acceleration sensor may also be provided to detect larger external shocks. By detecting various external shocks with improved accuracy, and aborting the recording operation of data if an external shock is detected, the corruption of data in adjacent tracks is substantially reduced to improve disk drive performance.
    Type: Application
    Filed: September 21, 2004
    Publication date: February 17, 2005
    Inventors: Takehiko Hamaguchi, Kyo Akagi, Hisashi Takano, Takayuki Ichihara
  • Patent number: 6839200
    Abstract: In a composite magnetic head comprising a magnetoresistive read head including a magnetic thin film having a magnetoresistive effect and soft magnetic members interposing the soft magnetic film between them through a non-magnetic insulation layer, an induction type write head including poles formed in a moving direction of a medium and a conductor crossing the poles, and disposed in the proximity of the magnetoresistive head, and a substrate supporting these heads, the present invention discloses a composite magnetic head characterized in that part of a floating surface inclusive of the magnetic head constituent members has recesses and the read/write operations to and from the medium are effected by the portion interposed by these recesses.
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: January 4, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Hisashi Takano, Naoki Koyama, Hideo Tanabe, Eijin Moriwaki, Isamu Yuito, Kazuo Shiiki, Tsuyoshi Ohnishi, Tohru Ishitani, Toshio Kobayashi, Hideo Todokoro, Chiaki Ishikawa
  • Patent number: 6822818
    Abstract: A hard disk drive and magnetic medium including a servo area, a data area divided into a plurality of sector blocks and at least one micro-servo area disposed between two sector blocks. There may be a micro-servo area immediately preceding each of the plurality of sector blocks. The micro-servo areas include an address mark and a track parity check code that allow the detection of an external shock that causes the recording (write) head to skip to an adjacent track in the hard disk medium. The micro-servo area is smaller than the servo areas, and various numbers of different track parity check codes can be used for different resolution of shock detection. An acceleration sensor may also be provided to detect larger external shocks. By detecting various external shocks with improved accuracy, and aborting the recording operation of data if an external shock is detected, the corruption of data in adjacent tracks is substantially reduced to improve disk drive performance.
    Type: Grant
    Filed: August 2, 2001
    Date of Patent: November 23, 2004
    Assignee: Hitachi, LTD
    Inventors: Takehiko Hamaguchi, Kyo Akagi, Hisashi Takano, Takayuki Ichihara
  • Publication number: 20040190172
    Abstract: A magnetic recording/reproducing apparatus includes a partial-response equalization circuit having frequency characteristic of cutting off low-frequency signal components inclusive of DC components; and a maximum-likelihood decoder, in which a reproduced signal outputted from the reproducing head is processed by the partial-response equalization circuit and then inputted into the maximum-likelihood decoder to be data-reproduced, thereby reducing a noise and distortion on the reproduced signal and reducing a data detection error rate.
    Type: Application
    Filed: April 14, 2004
    Publication date: September 30, 2004
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Toru Matsushita
  • Publication number: 20040150910
    Abstract: A magnetic head for perpendicular recording without writing from the lateral sides of a mains pole and without erasing data on adjacent tracks. A magnetic disk storage apparatus using the magnetic head. The lateral side of the main pole of a magnetic head for perpendicular recording may have an inverted tapered shape obtained by forming a groove as a track portion to an inorganic insulating layer and then forming a magnetic layer and then flattening the upper surface. A leading edge, a trailing edge, or both lateral edges of the magnetic head may be tapered. The taper may be either smooth and linear or curved in profile.
    Type: Application
    Filed: February 2, 2004
    Publication date: August 5, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Tomohiro Okada, Yoshiaki Kawato, Yasutaka Nishida, Yasuo Wakaki, Masafumi Mochizuki, Hisashi Takano
  • Publication number: 20040125489
    Abstract: Magnetic disk apparatus includes an electric wiringg 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: July 23, 2003
    Publication date: July 1, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Yohji Maruyama, Hiroshi Ikekame, Hisashi Takano
  • Patent number: 6741412
    Abstract: A magnetic recording/reproducing apparatus includes a partial-response equalization circuit having frequency characteristic of cutting off low-frequency signal components inclusive of DC components; and a maximum-likelihood decoder, in which a reproduced signal outputted from the reproducing head is processed by the partial-response equalization circuit and then inputted into the maximum-likelihood decoder to be data-reproduced, thereby reducing a noise and distortion on the reproduced signal and reducing a data detection error rate.
    Type: Grant
    Filed: June 8, 2001
    Date of Patent: May 25, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Toru Matsushita
  • Publication number: 20040090850
    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: Application
    Filed: November 5, 2003
    Publication date: May 13, 2004
    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
  • Publication number: 20040080865
    Abstract: In a composite magnetic head comprising a magnetoresistive read head including a magnetic thin film having a magnetoresistive effect and soft magnetic members interposing the soft magnetic film between them through a non-magnetic insulation layer, an induction type write head including poles formed in a moving direction of a medium and a conductor crossing the poles, and disposed in the proximity of the magnetoresistive head, and a substrate supporting these heads, the present invention discloses a composite magnetic head characterized in that part of a floating surface inclusive of the magnetic head constituent members has recesses and the read/write operations to and from the medium are effected by the portion interposed by these recesses.
    Type: Application
    Filed: October 20, 2003
    Publication date: April 29, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Hisashi Takano, Naoki Koyama, Hideo Tanabe, Eijin Moriwaki, Isamu Yuito, Kazuo Shiiki, Tsuyoshi Ohnishi, Tohru Ishitani, Toshio Kobayashi, Hideo Todokoro, Chiaki Ishikawa
  • Publication number: 20040075937
    Abstract: A magnetic recording disk drive can prevent the deterioration of the head off-track characteristics and the reduction of the drive performance even when an erase band asymmetry resulting from a skew angle exists. A write inhibit slice value for an inner peripheral side offset is made smaller than a write inhibit slice value for an outer peripheral side offset at a position where an erase band on the inner peripheral side is greater than an erase band on the outer peripheral side, so that the adjacent track on the outer peripheral side cannot easily erase a data track. On the contrary, the inner periphery and the outer periphery are paraphrased at a position where the erase band on the outer peripheral side is greater than the erase band on the inner peripheral side.
    Type: Application
    Filed: October 9, 2003
    Publication date: April 22, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Futoshi Tomiyama, Takehiko Hamaguchi, Toru Matsushita, Hideki Zaitsu, Reijiro Tsuchiya, Hisashi Takano
  • Publication number: 20040070869
    Abstract: To make a soft magnetic underlayer of a double layered perpendicular magnetic recording medium thinner than heretofore while avoiding saturation. Assuming that Tb1 is the thickness of the soft magnetic underlayer of the double layered perpendicular magnetic recording medium, BS2 the saturation flux density of the same, Tm the thickness of a magnetic recording head's main pole 1 along a track direction in the vicinity of its floating surface, TWW the track width of the same, and BS1 the saturation flux density of the same, then Tb1<(BS1×Tm×TWW)/2(BS2×(Tm+TWW)) is satisfied.
    Type: Application
    Filed: October 3, 2003
    Publication date: April 15, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Yasutaka Nishida, Hisashi Takano, Masafumi Mochizuki
  • Patent number: 6717760
    Abstract: A plurality of patterns are formed beforehand so that each of those patterns is deviated slightly from another in each sector in the track width direction, then the pattern is followed up, thereby obtaining both full-track profile and micro-track profile. A variation of a position signal is detected from this profile, thereby creating a table for correcting the non-linearity error of the position signal. Consequently, the distribution of the write/read-back property is measured, thereby enabling the track density to be improved. Furthermore, a variation of the position signal caused by a property variation of the head read-back element is detected and corrected, thereby enabling a high reliability and a high track density to be realized for the object magnetic recording disk apparatus.
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: April 6, 2004
    Assignee: Hitachi Global Storage Technologies, Japan, Ltd.
    Inventors: Takehiko Hamaguchi, Futoshi Tomiyama, Hideki Zaitsu, Hisashi Takano