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).
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Patent number: 8462468Abstract: 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: GrantFiled: April 27, 2011Date of Patent: June 11, 2013Assignee: Hitachi, Ltd.Inventors: Hiroyuki Katada, Takayuki Ichihara, Yoshiaki Kawato
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Patent number: 8085499Abstract: 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: GrantFiled: September 23, 2010Date of Patent: December 27, 2011Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Publication number: 20110292545Abstract: 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: ApplicationFiled: April 27, 2011Publication date: December 1, 2011Inventors: Hiroyuki Katada, Takayuki Ichihara, Yoshiaki Kawato
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Patent number: 7969691Abstract: 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: GrantFiled: January 15, 2008Date of Patent: June 28, 2011Assignee: Hitachi, Ltd.Inventors: Yoshiaki Kawato, Chiseki Haginoya, Kaori Suzuki
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Publication number: 20110007417Abstract: 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: ApplicationFiled: September 23, 2010Publication date: January 13, 2011Inventors: Yoshiaki KAWATO, Kazuhiro NAKAMOTO, Hiroyuki HOSHIYA, Yasuyuki OKADA, Masafumi MOCHIZUKI
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Patent number: 7813079Abstract: 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: GrantFiled: October 21, 2008Date of Patent: October 12, 2010Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Publication number: 20100009620Abstract: 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: ApplicationFiled: July 10, 2009Publication date: January 14, 2010Applicant: Toyota Jidosha Kabushiki KaishaInventors: Yoshiaki Kawato, Donald Federico
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Patent number: 7532433Abstract: 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: GrantFiled: May 22, 2007Date of Patent: May 12, 2009Assignee: Hitachi Global Storage Technologies JapaInventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Publication number: 20090059425Abstract: 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: ApplicationFiled: October 21, 2008Publication date: March 5, 2009Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Patent number: 7426091Abstract: 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: GrantFiled: March 31, 2006Date of Patent: September 16, 2008Assignee: Hitachi Global Storage Technologies Japan, LtdInventors: Yasuyuki Okada, Hiroyuki Hoshiya, Yoshiaki Kawato
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Publication number: 20080212239Abstract: 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: ApplicationFiled: January 15, 2008Publication date: September 4, 2008Inventors: Yoshiaki Kawato, Chiseki Haginoya, Kaori Suzuki
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Patent number: 7405905Abstract: 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: GrantFiled: September 8, 2006Date of Patent: July 29, 2008Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
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Patent number: 7348078Abstract: 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: GrantFiled: April 12, 2005Date of Patent: March 25, 2008Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
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Patent number: 7274626Abstract: 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: GrantFiled: July 20, 2004Date of Patent: September 25, 2007Assignee: Hitachi, Ltd.Inventors: Yoshiaki Kawato, Kenchi Ito
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Publication number: 20070217066Abstract: 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: ApplicationFiled: May 22, 2007Publication date: September 20, 2007Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Patent number: 7221538Abstract: 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: GrantFiled: August 20, 2003Date of Patent: May 22, 2007Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Publication number: 20070002492Abstract: 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: ApplicationFiled: September 8, 2006Publication date: January 4, 2007Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
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Patent number: 7145750Abstract: 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: GrantFiled: January 3, 2003Date of Patent: December 5, 2006Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
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Patent number: 7086140Abstract: 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: GrantFiled: August 25, 2004Date of Patent: August 8, 2006Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Tomohiro Okada, Yoshiaki Kawato, Kaori Suzuki, Hiroshi Fukui, Isao Nunokawa
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Publication number: 20060164759Abstract: 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: ApplicationFiled: March 31, 2006Publication date: July 27, 2006Inventors: Yasuyuki Okada, Hiroyuki Hoshiya, Yoshiaki Kawato