Patents by Inventor Gen Oikawa

Gen Oikawa 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: 8842388
    Abstract: Embodiments of the present invention provide a perpendicular magnetic recording head including a coil having small resistance. According to one embodiment, a nonmagnetic insulating layer formed on a main magnetic pole and a magnetic yoke are etched to form a recessed portion. The thickness of a conductive layer is increased by the depth of the recessed portion in a process for forming the conductive layer of the upper coil on the recessed portion to reduce resistance of the coil. Simultaneously with the formation of the recessed portion, a part of a second layer of a connection tab is removed. Simultaneously with the formation of the conductive layer of the upper coil, a space in which the part of the second layer of the connection tab is removed is filled with the same material as that of the conductive layer to further reduce the resistance of the entire coil.
    Type: Grant
    Filed: February 25, 2009
    Date of Patent: September 23, 2014
    Assignee: HGST Netherlands BV
    Inventors: Atsushi Kato, Ichiro Oodake, Gen Oikawa, Masahiko Soga
  • Patent number: 8351156
    Abstract: A perpendicular magnetic recording head according to one embodiment includes a main pole; first magnetic films arranged on both sides of the main pole in a track width direction via nonmagnetic films; and a second magnetic film arranged on a trailing side of the main pole via a nonmagnetic film; wherein the depths of the first magnetic films from an air bearing surface are smaller than the depth of the second magnetic film from the air bearing surface at least at a periphery of the main pole.
    Type: Grant
    Filed: December 15, 2009
    Date of Patent: January 8, 2013
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazue Kudo, Hiromi Shiina, Yohji Maruyama, Tetsuya Okai, Gen Oikawa, Shouji Tokutake
  • Patent number: 8125734
    Abstract: Embodiments of the present invention provide a magnetic slider of which terminals have a sufficiently large process margin for the laser condition in the SBB process. According to one embodiment, a magnetic slider comprises: a read element and a write element; plural wiring lines which are connected to the read element and the write element; a protective film which covers the read element, the write element and the plural-wiring lines; plural slider pads formed on the protective film; and plural studs which respectively connect the slider pads and the wiring lines and are covered by the protective film, wherein each of the slider pads comprises a chromium film, a nickel iron film and a gold film, the nickel iron film is formed between the chromium film and the gold film, and the chromium film is formed between the nickel iron film and one of the studs and is in contact with the protective film.
    Type: Grant
    Filed: September 5, 2007
    Date of Patent: February 28, 2012
    Assignee: Hitachi Global Storage Technologies, Netherlands B.V.
    Inventors: Hiroshi Umezaki, Seiji Nakagawa, Yuhsuke Matsumoto, Yoshihisa Takeo, Gen Oikawa, Hiroshi Kamio
  • Patent number: 8064161
    Abstract: Embodiments of the present invention help to provide a perpendicular magnetic recording head capable of writing a signal in a track having a small width. According to one embodiment, a perpendicular magnetic recording head includes an auxiliary pole, a main pole, a yoke, a coil, a first soft magnetic film and a second soft magnetic film. The yoke is in contact with the main pole. The coil is wound around a magnetic circuit composed of the auxiliary and main poles and the yoke. The first soft magnetic film is provided on both sides of the main pole with a non-magnetic film provided between the first soft magnetic film and the main pole. The second soft magnetic film is provided on the trailing side of the main pole with the non-magnetic film provided between the second soft magnetic film and the main pole. The first and second soft magnetic films are two types of plated magnetic films. One type of the plated magnetic films have respective thicknesses of 0.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: November 22, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazue Kudo, Hiromi Shiina, Gen Oikawa, Yohji Maruyama, Noriyuki Saiki
  • Patent number: 7995311
    Abstract: Embodiments of the present invention provide a magnetic shield composed of size-controlled small crystal grains and provide a more after-write read noise free thin film magnetic head. According to one embodiment of the present invention, an upper magnetic shield uses a multi-layered magnetic film formed by alternately stacking a face-centered cubic (fcc) crystalline magnetic thin layer and a body-centered cubic (bcc) crystalline magnetic thin layer by plating. The plating bath is such that the temperature is 30±1° C., pH is about 2.0?1.0 to 2.0+0.5, metal ion concentrations are about 5 to 25 (g/l) for Ni2+ and 5 to 15 (g/l) for Fe2+, saccharin sodium concentration is about 1.5±1.0 (g/l), sodium chloride concentration is about 25±5 (g/l), and boric acid concentration is about 25±5 (g/l). Each layer's crystal structure is different from that of its upper and lower layers, which results in size-controlled small crystal grains since the epitaxial growth is broken.
    Type: Grant
    Filed: June 19, 2007
    Date of Patent: August 9, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands BV
    Inventors: Kazue Kudo, Gen Oikawa, Yohji Maruyama, Noriyuki Saiki, Hiromi Shiina
  • Patent number: 7842408
    Abstract: Embodiments of the present invention provide a magnetic disk drive capable of allowing higher data transfer rates and higher recording densities. According to one embodiment, an upper magnetic core and lower magnetic core comprise a multi-layered magnetic film formed by alternately stacking a face-centered cubic (fcc) crystalline magnetic thin layer and a body-centered cubic (bcc) crystalline magnetic thin layer by plating. The plating bath is such that the temperature is about 30±1° C., pH is about 2.0?1.0 to 2.0+0.5, metal ion concentrations are about 5 to 25 (g/l) for Ni2+ and 5 to 15 (g/l) for Fe2+, saccharin sodium concentration is about 1.5±1.0 (g/l), sodium chloride concentration is about 25±5 (g/l), and boric acid concentration is about 25±5 (g/l). Since each layer's crystal structure is different from that of its adjacent lower layer, epitaxial growth is broken within each layer.
    Type: Grant
    Filed: June 19, 2007
    Date of Patent: November 30, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazue Kudo, Gen Oikawa, Yohji Maruyama, Noriyuki Saiki, Hiromi Shiina
  • Publication number: 20100157476
    Abstract: A perpendicular magnetic recording head according to one embodiment includes a main pole; first magnetic films arranged on both sides of the main pole in a track width direction via nonmagnetic films; and a second magnetic film arranged on a trailing side of the main pole via a nonmagnetic film; wherein the depths of the first magnetic films from an air bearing surface are smaller than the depth of the second magnetic film from the air bearing surface at least at a periphery of the main pole.
    Type: Application
    Filed: December 15, 2009
    Publication date: June 24, 2010
    Inventors: Kazue Kudo, Hiromi Shiina, Yohji Maruyama, Tetsuya Okai, Gen Oikawa, Shouji Tokutake
  • Patent number: 7679860
    Abstract: Embodiments of the invention provide a magnetic film capable of providing a higher saturation magnetic flux density as compared with the conventional one, a process of forming the magnetic film, a thin film magnetic head that makes use of the magnetic film, and a magnetic disk drive having this thin film magnetic head. In one embodiment, a magnetic film contains Co, Ni, and Fe, and its composition is such that 10?Co<20 wt %, 0?Ni?2 wt %, and 80<Fe?90 wt %. This magnetic film is a plating layer formed by electroplating. The face interval variation of crystal surface perpendicular to the layer surface relative to a crystal surface parallel to the layer surface is about 0.4% or more, whereby the saturation magnetic flux density (Bs) is greater than about 2.4 T.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: March 16, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazue Kudo, Gen Oikawa, Youji Maruyama, Hiromi Shiina
  • Patent number: 7589937
    Abstract: Embodiments of the invention provide a lustrous and uniform plating film having high-performance magnetic characteristics and a thin film magnetic head usable in a high frequency recording band by using the plating film of the invention at a magnetic pole portion. Plating is performed in a plating bath at a low pH of about 1.5 to 2.3. The accuracy of pH control is improved. A magnetic film with the addition of a high resistive metal such as Cr or Mo is formed under the plating condition. Further, the magnetic characteristic is improved by applying a heat treatment to the plating film in a magnetic field, according to specific embodiments of the present invention. A plating film with brightness and uniformity having high saturation magnetic flux density can be formed by reducing the hysteresis loss and the eddy current loss as the magnetic characteristics by the above techniques.
    Type: Grant
    Filed: July 19, 2004
    Date of Patent: September 15, 2009
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Gen Oikawa, Kazue Kudo, Youji Maruyama, Noriyuki Saiki, Hiromi Shiina
  • Publication number: 20090213496
    Abstract: Embodiments of the present invention provide a perpendicular magnetic recording head including a coil having small resistance. According to one embodiment, a nonmagnetic insulating layer formed on a main magnetic pole and a magnetic yoke are etched to form a recessed portion. The thickness of a conductive layer is increased by the depth of the recessed portion in a process for forming the conductive layer of the upper coil on the recessed portion to reduce resistance of the coil. Simultaneously with the formation of the recessed portion, a part of a second layer of a connection tab is removed. Simultaneously with the formation of the conductive layer of the upper coil, a space in which the part of the second layer of the connection tab is removed is filled with the same material as that of the conductive layer to further reduce the resistance of the entire coil.
    Type: Application
    Filed: February 25, 2009
    Publication date: August 27, 2009
    Inventors: Atsushi Kato, Ichiro Oodake, Gen Oikawa, Masahiko Soga
  • Publication number: 20090154014
    Abstract: Embodiments of the present invention improve the recording density of a magnetic disk drives by providing a write head capable of writing adequately on a narrow trackwidth and high coercivity recording media. According to one embodiment, a thin film magnetic head has a write head which comprises at least a main magnetic pole, a yoke and a return pole, wherein a magnetic film which constitutes at least a part of the main magnetic pole, the yoke or the return pole is formed by alternately plating first magnetic layers and second magnetic layers, each of the first magnetic layer being of the body-centered cubic phase and containing at least two of elements Co, Ni and Fe, and each of the second magnetic layer being of the face-centered cubic phase and containing at least two of elements Co, Ni and Fe. The thin-film magnetic head can attain high Bs even if the magnetic film is thinned. In addition, high ? can be attained even when the recording frequency is high.
    Type: Application
    Filed: November 25, 2008
    Publication date: June 18, 2009
    Inventors: Kazue Kudo, Hiromi Shiina, Yoji Maruyama, Gen Oikawa
  • Patent number: 7515380
    Abstract: At least one of lower and upper magnetic cores is composed of magnetic films each of which contains two or more elements of Co, Ni, and Fe, which are formed by electroplating in a plating bath with pH 2 or less, and which have a saturation magnetic flux density of 23,000 gauss or more.
    Type: Grant
    Filed: March 13, 2007
    Date of Patent: April 7, 2009
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Kazue Kudo, Gen Oikawa, Tetsuya Okai, Ichiro Oodake, Hiromi Shiina
  • Publication number: 20090059427
    Abstract: Embodiments of the present invention help to provide a perpendicular magnetic recording head capable of writing a signal in a track having a small width. According to one embodiment, a perpendicular magnetic recording head includes an auxiliary pole, a main pole, a yoke, a coil, a first soft magnetic film and a second soft magnetic film. The yoke is in contact with the main pole. The coil is wound around a magnetic circuit composed of the auxiliary and main poles and the yoke. The first soft magnetic film is provided on both sides of the main pole with a non-magnetic film provided between the first soft magnetic film and the main pole. The second soft magnetic film is provided on the trailing side of the main pole with the non-magnetic film provided between the second soft magnetic film and the main pole. The first and second soft magnetic films are two types of plated magnetic films. One type of the plated magnetic films have respective thicknesses of 0.
    Type: Application
    Filed: August 28, 2008
    Publication date: March 5, 2009
    Inventors: Kazue Kudo, Hiromi Shiina, Gen Oikawa, Yoji Maruyama, Noriyuki Saiki
  • Patent number: 7485378
    Abstract: A magnetic film capable of generating strong magnetic fields even in a high frequency region, a manufacturing method therefore and a thin film magnetic head capable of recording even in a high frequency region are provided. In one embodiment, the magnetic film is manufactured by using a 88FeNi film of 200 nm thick having minimum Hk of 0.32 Oe (25.6 A/m) as a main magnetic film and selecting a 20 wt % FeNi film of a similar FeNi alloy plating film having low Hk and low Hc as an interlayer material. A stacked film comprising (88FeNi/20FeNi)×10 layers is prepared so that the total thickness of the main magnetic film is 2 ?m. The 88FeNi film is prepared by application of a DC current in a 88FeNi plating bath, and the 20FeNi film is prepared by pulse plating successively in the same bath.
    Type: Grant
    Filed: March 18, 2005
    Date of Patent: February 3, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Gen Oikawa, Kazue Kudo, Youji Maruyama, Hiromi Shiina
  • Publication number: 20080075977
    Abstract: Embodiments of the present invention provide a magnetic disk drive capable of allowing higher data transfer rates and higher recording densities. According to one embodiment, an upper magnetic core and lower magnetic core comprise a multi-layered magnetic film formed by alternately stacking a face-centered cubic (fcc) crystalline magnetic thin layer and a body-centered cubic (bcc) crystalline magnetic thin layer by plating. The plating bath is such that the temperature is about 30±1° C., pH is about 2.0?1.0 to 2.0+0.5, metal ion concentrations are about 5 to 25 (g/l) for Ni2+ and 5 to 15 (g/l) for Fe2+, saccharin sodium concentration is about 1.5±1.0 (g/l), sodium chloride concentration is about 25±5 (g/l), and boric acid concentration is about 25±5 (g/l). Since each layer's crystal structure is different from that of its adjacent lower layer, epitaxial growth is broken within each layer.
    Type: Application
    Filed: June 19, 2007
    Publication date: March 27, 2008
    Applicant: Hitachi Global Storage Netherlands B.V.
    Inventors: Kazue Kudo, Gen Oikawa, Yohji Maruyama, Noriyuki Saiki, Hiromi Shiina
  • Publication number: 20080062565
    Abstract: Embodiments of the present invention provide a magnetic slider of which terminals have a sufficiently large process margin for the laser condition in the SBB process. According to one embodiment, a magnetic slider comprises: a read element and a write element; plural wiring lines which are connected to the read element and the write element; a protective film which covers the read element, the write element and the plural-wiring lines; plural slider pads formed on the protective film; and plural studs which respectively connect the slider pads and the wiring lines and are covered by the protective film, wherein each of the slider pads comprises a chromium film, a nickel iron film and a gold film, the nickel iron film is formed between the chromium film and the gold film, and the chromium film is formed between the nickel iron film and one of the studs and is in contact with the protective film.
    Type: Application
    Filed: September 5, 2007
    Publication date: March 13, 2008
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hiroshi Umezaki, Seiji Nakagawa, Yuhsuke Matsumoto, Yoshihisa Takeo, Gen Oikawa, Hiroshi Kamio
  • Publication number: 20080002308
    Abstract: Embodiments of the present invention provide a magnetic shield composed of size-controlled small crystal grains and provide a more after-write read noise free thin film magnetic head. According to one embodiment of the present invention, an upper magnetic shield uses a multi-layered magnetic film formed by alternately stacking a face-centered cubic (fcc) crystalline magnetic thin layer and a body-centered cubic (bcc) crystalline magnetic thin layer by plating. The plating bath is such that the temperature is 30±1° C., pH is about 2.0-1.0 to 2.0+0.5, metal ion concentrations are about 5 to 25 (g/l) for Ni2+ and 5 to 15 (g/l) for Fe2+, saccharin sodium concentration is about 1.5±1.0 (g/l), sodium chloride concentration is about 25±5 (g/l), and boric acid concentration is about 25±5 (g/l). Each layer's crystal structure is different from that of its upper and lower layers, which results in size-controlled small crystal grains since the epitaxial growth is broken.
    Type: Application
    Filed: June 19, 2007
    Publication date: January 3, 2008
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazue Kudo, Gen Oikawa, Yohji Maruyama, Noriyuki Saiki, Hiromi Shiina
  • Patent number: 7274541
    Abstract: In formation of an upper shield of a magnetic thin film head by electroplating, a current density of electroplating is regulated stepwise with time. Thus, in the upper shield formation, a film composition and magnetic characteristic with respect to the direction of film thickness can be controlled precisely, making it possible to provide a magnetic thin film head featuring significantly reduced noise-after-write and output fluctuation.
    Type: Grant
    Filed: April 1, 2005
    Date of Patent: September 25, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Gen Oikawa, Shuichi Kojima, Harunobu Saito, Noriyuki Saiki, Masayasu Kagawa, Akira Kondo, Kenji Ishikake, Hiromi Shiina
  • Patent number: 7267757
    Abstract: At least one of lower and upper magnetic cores is composed of magnetic films each of which contains two or more elements of Co, Ni, and Fe, which are formed by electroplating in a plating bath with pH 2 or less, and which have a saturation magnetic flux density of 23,000 gauss or more.
    Type: Grant
    Filed: September 18, 2003
    Date of Patent: September 11, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Kazue Kudo, Gen Oikawa, Tetsuya Okai, Ichiro Oodake, Hiromi Shiina
  • Publication number: 20070177299
    Abstract: At least one of lower and upper magnetic cores is composed of magnetic films each of which contains two or more elements of Co, Ni, and Fe, which are formed by electroplating in a plating bath with pH 2 or less, and which have a saturation magnetic flux density of 23,000 gauss or more.
    Type: Application
    Filed: March 13, 2007
    Publication date: August 2, 2007
    Applicant: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Kazue Kudo, Gen Oikawa, Tetsuya Okai, Ichiro Oodake, Hiromi Shiina