Patents by Inventor Yoshiaki Kawato

Yoshiaki Kawato 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: 8462468
    Abstract: In a magnetic head to be used for a shingled recording method, degradation of a signal resolution and a decrease in a signal-to-noise ratio which are caused by an asymmetrical inter-bit transition curvature are prevented, and a low bit error rate is realized. A magnetic head includes a recording head and a reproducing head. The reproducing head includes a pair of magnetic shields and a sensor sandwiched between the pair of magnetic shields. The gap between the magnetic shields is formed so that the longitudinal direction thereof gets inclined by a certain angle with respect to a cross-track direction in line with the shape of a curvature of an inter-bit transition on an effective record track in a record pattern recorded on a recording medium.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: June 11, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Katada, Takayuki Ichihara, Yoshiaki Kawato
  • Patent number: 8085499
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: September 23, 2010
    Date of Patent: December 27, 2011
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20110292545
    Abstract: In a magnetic head to be used for a shingled recording method, degradation of a signal resolution and a decrease in a signal-to-noise ratio which are caused by an asymmetrical inter-bit transition curvature are prevented, and a low bit error rate is realized. A magnetic head includes a recording head and a reproducing head. The reproducing head includes a pair of magnetic shields and a sensor sandwiched between the pair of magnetic shields. The gap between the magnetic shields is formed so that the longitudinal direction thereof gets inclined by a certain angle with respect to a cross-track direction in line with the shape of a curvature of an inter-bit transition on an effective record track in a record pattern recorded on a recording medium.
    Type: Application
    Filed: April 27, 2011
    Publication date: December 1, 2011
    Inventors: Hiroyuki Katada, Takayuki Ichihara, Yoshiaki Kawato
  • Patent number: 7969691
    Abstract: A read sensor is disposed near a main pole, thereby reducing the distance between the read sensor and a write sensor. In this case, however, a magnetic field generated from the main pole affects magnetization of a free layer and a pinned layer of a magnetoresistive film, thereby causing the magnetizing directions to rotate, a magnetic barrier to be generated, and the read property to be degraded. According to the present invention, a main pole and a yoke configure a magnetic circuit together with a sub-pole and a soft magnetic under layer of the magnetic disk and an exciting coil magnetizes the magnetic circuit, thereby a recording magnetic field is applied to a recording layer to record information bits on the layer. And in order to sharpen the magnetic field distribution generated by the main pole, a trailing shield made of a ferromagnetic material is disposed at the trailing side of the main pole adjacently.
    Type: Grant
    Filed: January 15, 2008
    Date of Patent: June 28, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Yoshiaki Kawato, Chiseki Haginoya, Kaori Suzuki
  • Publication number: 20110007417
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: September 23, 2010
    Publication date: January 13, 2011
    Inventors: Yoshiaki KAWATO, Kazuhiro NAKAMOTO, Hiroyuki HOSHIYA, Yasuyuki OKADA, Masafumi MOCHIZUKI
  • Patent number: 7813079
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: October 12, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20100009620
    Abstract: An inside air/outside air switching device that includes: an inside air/outside air switching case that has an outside air inlet which opens into an engine room, a first inside air inlet and a second inside air inlet which open into a vehicle compartment; an inside air/outside air switching door that is provided in the inside air/outside air switching case, and that switches an open inlet between the first inside air inlet and the outside air inlet; an inside air introduction support door that opens and closes the second inside air inlet; and a noise insulation member that is provided in such a manner that an operation of the inside air introduction support door is not interfered with, and that blocks out noise which is generated in the engine room and which proceeds from the outside air inlet toward the second inside air inlet when the outside air inlet is open.
    Type: Application
    Filed: July 10, 2009
    Publication date: January 14, 2010
    Applicant: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yoshiaki Kawato, Donald Federico
  • Patent number: 7532433
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: May 22, 2007
    Date of Patent: May 12, 2009
    Assignee: Hitachi Global Storage Technologies Japa
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20090059425
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: October 21, 2008
    Publication date: March 5, 2009
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Patent number: 7426091
    Abstract: The disclosed invention provides a magnetic head of high stability in which “erase after write” is prevented. Here is provided a magnetic head comprising a thin-film magnetic head for perpendicular magnetic recording, the thin-film magnetic head including a main pole with its tip facing a magnetic recording medium and coils for exciting the main pole, wherein the tip of or at least a part of the main pole consists of a soft magnetic multilayer containing laminations, each of which comprises a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film, wherein the antiparallel coupling layer causes antiferromagnetic interlayer coupling of the first ferromagnetic film and the second ferromagnetic film.
    Type: Grant
    Filed: March 31, 2006
    Date of Patent: September 16, 2008
    Assignee: Hitachi Global Storage Technologies Japan, Ltd
    Inventors: Yasuyuki Okada, Hiroyuki Hoshiya, Yoshiaki Kawato
  • Publication number: 20080212239
    Abstract: A read sensor is disposed near a main pole, thereby reducing the distance between the read sensor and a write sensor. In this case, however, a magnetic field generated from the main pole affects magnetization of a free layer and a pinned layer of a magnetoresistive film, thereby causing the magnetizing directions to rotate, a magnetic barrier to be generated, and the read property to be degraded. According to the present invention, a main pole and a yoke configure a magnetic circuit together with a sub-pole and a soft magnetic under layer of the magnetic disk and an exciting coil magnetizes the magnetic circuit, thereby a recording magnetic field is applied to a recording layer to record information bits on the layer. And in order to sharpen the magnetic field distribution generated by the main pole, a trailing shield made of a ferromagnetic material is disposed at the trailing side of the main pole adjacently.
    Type: Application
    Filed: January 15, 2008
    Publication date: September 4, 2008
    Inventors: Yoshiaki Kawato, Chiseki Haginoya, Kaori Suzuki
  • Patent number: 7405905
    Abstract: There is provided a perpendicular magnetic recording and reproducing system in which the overwrite erase ratio of a perpendicular magnetic head has been improved to prevent the deterioration of an overwrite property. In the perpendicular magnetic head, a third magnetic pole composed of a soft magnetic layer is formed on the leading side of a recording magnetic pole via a non-magnetic layer, thereby reducing magnetic interference from magnetization on a medium with the recording magnetic pole and preventing the deterioration of the overwrite property.
    Type: Grant
    Filed: September 8, 2006
    Date of Patent: July 29, 2008
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
  • Patent number: 7348078
    Abstract: An improved perpendicular magnetic recording medium and an improved magnetic storage apparatus are provided, which are suitable for high speed and high density magnetic recording. A magnetic under layer of a two-layered perpendicular magnetic recording medium includes three layers: a ferromagnetic layer; a non-magnetic layer; and a ferromagnetic layer, wherein the ferromagnetic layers are antiferromagnetically coupled with each other, thereby preventing a magnetic flux from a magnetic wall in a magnetic under layer from entering a read back head.
    Type: Grant
    Filed: April 12, 2005
    Date of Patent: March 25, 2008
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Patent number: 7274626
    Abstract: A perpendicular magnetic recording medium for thermo-magnetic printing has an ultra-high recording density and is resistant to thermal decay of magnetization. An intermediate layer of the medium is provided between a first recording layer using a low-noise Co alloy ferromagnetic substance and a second recording layer using a ferrimagnetic substance (e.g., a rare-earth element-transition metal compound) having a compensation temperature below an operation ambient temperature. A magnetic field is applied thereto to form a magnetization pattern on the first recording layer. It is then heated-up to be printed onto the second recording layer, which has a higher coercivity at the ambient temperature, and a recording field is suitably set to form a magnetization pattern only on the first recording layer. The magnetization pattern is printed from the first recording layer to the second recording layer.
    Type: Grant
    Filed: July 20, 2004
    Date of Patent: September 25, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Yoshiaki Kawato, Kenchi Ito
  • Publication number: 20070217066
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field exceeding 10 kOe (oersted), while also modified to suppress remanent magnetic fields occurring immediately after writing operation. In a perpendicular magnetic head comprising a main pole, a return path for supplying a magnetic flux to that main pole, and an conductive coil for excitation of the main pole and return path, the main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer, the low saturation flux density layer has a thickness within 0.5 to 5 nanometers, the high saturation flux density layer has a thickness from 10 to 50 nanometers for suppressing remanent magnetization and preventing erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: May 22, 2007
    Publication date: September 20, 2007
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Patent number: 7221538
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field exceeding 10 kOe while suppressing remanent magnetic fields occurring immediately after write operations. The perpendicular magnetic head comprises a main pole, a return path for supplying a magnetic flux to that main pole, and a conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer has a thickness within 0.5 to 5 nanometers, and The high saturation flux density layer has a thickness from 10 to 50.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: May 22, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20070002492
    Abstract: There is provided a perpendicular magnetic recording and reproducing system in which the overwrite erase ratio of a perpendicular magnetic head has been improved to prevent the deterioration of an overwrite property. In the perpendicular magnetic head, a third magnetic pole composed of a soft magnetic layer is formed on the leading side of a recording magnetic pole via a non-magnetic layer, thereby reducing magnetic interference from magnetization on a medium with the recording magnetic pole and preventing the deterioration of the overwrite property.
    Type: Application
    Filed: September 8, 2006
    Publication date: January 4, 2007
    Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
  • Patent number: 7145750
    Abstract: There is provided a perpendicular magnetic recording and reproducing system in which the overwrite erase ratio of a perpendicular magnetic head has been improved to prevent the deterioration of an overwrite property. In the perpendicular magnetic head, a third magnetic pole composed of a soft magnetic layer is formed on the leading side of a recording magnetic pole via a non-magnetic layer, thereby reducing magnetic interference from magnetization on a medium with the recording magnetic pole and preventing the deterioration of the overwrite property.
    Type: Grant
    Filed: January 3, 2003
    Date of Patent: December 5, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
  • Patent number: 7086140
    Abstract: A method of fabricating a thin film magnetic recording head including a perpendicular recording head having an auxiliary pole, a main pole and a shield against an external magnetic field. The shield against the external magnetic field is formed so that an edge of the shield against the external magnetic field is disposed at a position recessed at least from an edge of the main pole relative to a surface against a medium.
    Type: Grant
    Filed: August 25, 2004
    Date of Patent: August 8, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Tomohiro Okada, Yoshiaki Kawato, Kaori Suzuki, Hiroshi Fukui, Isao Nunokawa
  • Publication number: 20060164759
    Abstract: The disclosed invention provides a magnetic head of high stability in which “erase after write” is prevented. Here is provided a magnetic head comprising a thin-film magnetic head for perpendicular magnetic recording, the thin-film magnetic head including a main pole with its tip facing a magnetic recording medium and coils for exciting the main pole, wherein the tip of or at least a part of the main pole consists of a soft magnetic multilayer containing laminations, each of which comprises a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film, wherein the antiparallel coupling layer causes antiferromagnetic interlayer coupling of the first ferromagnetic film and the second ferromagnetic film.
    Type: Application
    Filed: March 31, 2006
    Publication date: July 27, 2006
    Inventors: Yasuyuki Okada, Hiroyuki Hoshiya, Yoshiaki Kawato