Patents by Inventor Takashi Namekawa

Takashi Namekawa 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: 20030025196
    Abstract: The present invention is a semiconductor apparatus having at least a part of a semiconductor device conjugated to a metal material for heat sink via an electric insulating material, wherein said electric insulating material is a bismuth glass layer.
    Type: Application
    Filed: July 30, 2002
    Publication date: February 6, 2003
    Applicant: HITACHI, LTD.
    Inventors: Takayoshi Nakamura, Ryuichi Saito, Akihiro Tamba, Takashi Naitou, Hiroki Yamamoto, Takashi Namekawa
  • Publication number: 20030025195
    Abstract: The present invention is a semiconductor apparatus having at least a part of a semiconductor device conjugated to a metal material for heat sink via an electric insulating material, wherein said electric insulating material is a bismuth glass layer.
    Type: Application
    Filed: March 18, 2002
    Publication date: February 6, 2003
    Applicant: HITACHI, LTD.
    Inventors: Takayoshi Nakamura, Ryuichi Saito, Akihiro Tamba, Takashi Naitou, Hiroki Yamamoto, Takashi Namekawa
  • Patent number: 6512655
    Abstract: Provided are a glass such as a sealing glass which contains a rare earth element and crystalline particles, a structure made by sealing with said sealing glass, a magnetic head made by bonding using said sealing glass, and a magnetic recording and reproducing apparatus on which said magnetic heads are mounted. According to the glass of the present invention, magnetic heads, and other structures can be bonded at low temperatures and a high bond strength can be attained, and thus, magnetic heads having high-speed sliding properties and magnetic recording and reproducing apparatuses of high reliability can be obtained. The glass can be also used for heat resistant parts such as a pannel glass for a cathode-ray tube and the like.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: January 28, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Ken Takahashi, Noriyuki Kumasaka, Kenkichi Inada
  • Publication number: 20030008760
    Abstract: A glass including SiO2, Na2O, MgO, Al2O3, and cobalt oxide, wherein the cobalt oxide is 4.5-85 wt % as an oxide of CoO or 4.9-91 wt % as an oxide of Co3O4.
    Type: Application
    Filed: July 30, 2002
    Publication date: January 9, 2003
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Yasutaka Suzuki, Ken Takahashi, Motoyasu Terao, Toshimichi Shintani
  • Patent number: 6503858
    Abstract: Provided are a glass such as a sealing glass which contains a rare earth element and crystalline particles, a structure made by sealing with said sealing glass, a magnetic head made by bonding using said sealing glass, and a magnetic recording and reproducing apparatus on which said magnetic heads are mounted. According to the glass of the present invention, magnetic heads, and other structures can be bonded at low temperatures and a high bond strength can be attained, and thus, magnetic heads having high-speed sliding properties and magnetic recording and reproducing apparatuses of high reliability can be obtained. The glass can be also used for heat resistant parts such as a pannel glass for a cathode-ray tube and the like.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: January 7, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Ken Takahashi, Noriyuki Kumasaka, Kenkichi Inada
  • Patent number: 6440517
    Abstract: A glass including SiO2, Na2O, MgO, Al2O3 and cobalt oxide, wherein the cobalt oxide is 4.5-85 wt % as an oxide of CoO or 4.9-91 wt % as an oxide of Co3O4.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: August 27, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Yasutaka Suzuki, Ken Takahashi, Motoyasu Terao, Toshimichi Shintani
  • Patent number: 6411591
    Abstract: The optical recording medium has sandwiched between protective layers a mask layer whose refractive index is changed in one part within a light spot when irradiated with a laser beam of 2 to 4 mW. In a region where the refractive index is changed or in other remaining regions, the difference in the amount of reflected light between the crystalline state and the amorphous state is so small that a reproduced signal is difficult to identify. By reducing the size of a portion where the reproduced signal can be seen, it is possible to read high-density recorded information.
    Type: Grant
    Filed: February 17, 2000
    Date of Patent: June 25, 2002
    Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.
    Inventors: Koichi Moritani, Akemi Hirotsune, Motoyasu Terao, Yasushi Miyauchi, Toshimichi Shintani, Takashi Naito, Takashi Namekawa, Hiroki Yamamoto
  • Publication number: 20020034665
    Abstract: A magnetic recording medium comprising a substrate 1, an inorganic compound layer 2 which works as a shielding layer, a magnetic layer 3 and a protective layer 4 which are laminated on said substrate; wherein said inorganic compound layer 2 comprises column-like crystal particles 6 and amorphous grain boundary phases isolating said particles 6, wherein said magnetic layer 3 has magnetic particles 14 arranged regularly and epitaxially grows on said inorganic compound layer 2, and wherein the grain sizes and the standard grain size deviation of magnetic particles 14 of said magnetic layer 3 reflect those of said inorganic compound layer 2.
    Type: Application
    Filed: February 28, 2001
    Publication date: March 21, 2002
    Inventors: Tetsuo Nakazawa, Yuzo Kozono, Takashi Naito, Tatsumi Hirano, Hiroki Yamamoto, Takashi Namekawa, Yasutaka Suzuki
  • Publication number: 20010038930
    Abstract: A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% or less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.
    Type: Application
    Filed: March 1, 2001
    Publication date: November 8, 2001
    Inventors: Hiroki Yamamoto, Takashi Namekawa, Takashi Naito, Yasutaka Suzuki, Akira Kato, Noriyuki Takeo, Kiyoshi Akamatsu, Youichi Inomata, Masatomo Terakado, Ken Takahashi
  • Patent number: 6177169
    Abstract: A glass including SiO2, Na2O, MgO, Al2O3 and cobalt oxide, wherein the cobalt oxide is 4.5-85 wt % as an oxide of CoO or 4.9-91 wt % as an oxide of Co3O4.
    Type: Grant
    Filed: November 3, 1999
    Date of Patent: January 23, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Yasutaka Suzuki, Ken Takahashi, Motoyasu Terao, Toshimichi Shintani
  • Patent number: 6150027
    Abstract: Provided are a glass such as a sealing glass which contains a rare earth element and crystalline particles, a structure made by sealing with said sealing glass, a magnetic head made by bonding using said sealing glass, and a magnetic recording and reproducing apparatus on which said magnetic heads are mounted. According to the glass of the present invention, magnetic heads, and other structures can be bonded at low temperatures and a high bond strength can be attained, and thus, magnetic heads having high-speed sliding properties and magnetic recording and reproducing apparatuses of high reliability can be obtained. The glass can be also used for heat resistant parts such as a pannel glass for a cathode-ray tube and the like.
    Type: Grant
    Filed: June 12, 1996
    Date of Patent: November 21, 2000
    Assignee: Hitachi, LTD
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Ken Takahashi, Noriyuki Kumasaka, Kenkichi Inada
  • Patent number: 6136401
    Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.
    Type: Grant
    Filed: January 20, 2000
    Date of Patent: October 24, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Ken Takahashi, Masahiro Watanabe, Noriyuki Takeo
  • Patent number: 6040029
    Abstract: In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.
    Type: Grant
    Filed: July 3, 1997
    Date of Patent: March 21, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Ken Takahashi, Masahiro Watanabe, Noriyuki Takeo
  • Patent number: 5985401
    Abstract: An optical information recording medium, which is not deteriorated after repeated reading out and writing in operations, is provided by forming a glass thin film, which varies the intensity or the intensity distribution of light, on a substrate, and providing a recording film, a protective film, and a reflecting film thereon.
    Type: Grant
    Filed: June 4, 1998
    Date of Patent: November 16, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yamamoto, Takashi Naito, Takashi Namekawa, Yasutaka Suzuki, Ken Takahashi, Motoyasu Terao, Toshimichi Shintani
  • Patent number: 5519555
    Abstract: A magnetic head for use in a magnetic recording and reproducing system, which head is excellent in magnetic properties, resistance to abrasion, durability and mass-producibility, comprises a pair of magnetic cores each having a substrate and a magnetic alloy film formed on the substrate, the cores being disposed in a manner such that the magnetic alloy films are opposed to and slightly spaced apart from each other, and glass bondings disposed between the magnetic alloy films to integrate the pair of magnetic cores, and a process for producing the same, and a magnetic recording and reproducing system using the magnetic head.
    Type: Grant
    Filed: August 3, 1994
    Date of Patent: May 21, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Naitoh, Takashi Namekawa, Seiichi Yamada, Kunihiro Maeda, Kenkichi Inada
  • Patent number: 5239434
    Abstract: A magnetic head of a structure in which a pair of magnetic cores, each comprising a magnetic film formed on a support, are butted and bonded to each other with glass and with the interposition of a non-magnetic gap material. The bonding glass is an oxide type glass containing vanadium as main constituent, and 55% or more of vanadium contained in the glass is tetravalent vanadium. This magnetic head is excellent in mass productivity, wear resistance, scratch resistance, weather resistance and magnetic properties.
    Type: Grant
    Filed: September 26, 1991
    Date of Patent: August 24, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Naito, Takashi Namekawa, Kunihiro Maeda, Yasutaka Suzuki, Kouji Arikawa, Tsukasa Ohata
  • Patent number: 4816949
    Abstract: The present invention relates to a magnetic head in which a magnetic metal film comprising a Co-containing amorphous alloy and a crystallizable glass of the PbO-B.sub.2 O.sub.3 -ZnO system as a solder glass are used. The magnetic head of the present invention has about 2 times higher recording density than the conventional one as a magnetic head for floppy disks and hard disks because an amorphous alloy is used. Since a crystallizable glass is used as the glass, there can be obtained a magnetic head having a high strength and superior humidity resistance and reliability.
    Type: Grant
    Filed: September 9, 1987
    Date of Patent: March 28, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Seiichi Yamada, Takashi Naitoh, Takashi Namekawa, Akira Ikegami, Ryoo Gotoo, Toshikazu Nishiyama
  • Patent number: 4794483
    Abstract: A magnetic head has a layer of amorphous magnetic alloy arranged to define a magnetic gap therebetween, the layer being bonded with a bonding glass having a viscosity of 10.sup.5 poises or less at a temperature by at least 50.degree. C. lower than the crystallization temperature of the amorphous magnetic alloy, a good water resistance after sintering and a low coefficient of thermal expansion such as 100.times.10.sup.-7 /.degree.C. or less. The bonding glass contains 55 to 70% by weight of V.sub.2 O.sub.5, 17 to 25% by weight of P.sub.2 O.sub.5, 3 to 20% by weight of Sb.sub.2 O.sub.3, 0 to 20% by weight of PbO, 0 to 15% by weight of Tl.sub.2 O, and 0 to 5% by weight of Nb.sub.2 O.sub.5.
    Type: Grant
    Filed: October 14, 1986
    Date of Patent: December 27, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Naitoh, Takashi Namekawa, Seiichi Yamada, Satoru Ogihara, Juichi Morikawa
  • Patent number: 4780695
    Abstract: A fire resistant refractory leakage coaxial cable assembly formed by placing a sheet of heat resistant organic film between the internal conductor and the external conductor of a leakage coaxial cable. The seam formed by the two edges of the film is positioned upwardly, so that molten insulated material will be contained by the film without flowing through the seam.
    Type: Grant
    Filed: February 11, 1987
    Date of Patent: October 25, 1988
    Assignee: Hitachi Cable Ltd.
    Inventors: Toru Watari, Hideaki Saito, Hideki Yagyu, Takashi Namekawa
  • Patent number: 4741849
    Abstract: The glass composition is particularly applicable for ferrite constituents used for a highly efficient magnetic head. The composition essentially consists of (a) 55-70 wt % of V.sub.2 O.sub.5, (b) 18-wt % of P.sub.2 O.sub.5, (c1) up to 10 wt % of at least one alkaline metal oxide selected from Na.sub.2 O, K.sub.2 O, Rb.sub.2 O, and Cs.sub.2 O and (c3) up to 10 wt % of Tl.sub.2 O. The composition is in a non-crystalline state during reheating and has a softening temperature of 310.degree. C.-400.degree. C. and a thermal expansion coefficient of 70-130.times.10.sup.-7 /.degree.C.
    Type: Grant
    Filed: January 12, 1987
    Date of Patent: May 3, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Naito, Takashi Namekawa, Satoru Ogihara