Patents by Inventor Hirosi Akiyama

Hirosi Akiyama 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).

  • Semiconductor device having thermal stress resistance structure
    Patent number: 5621243
    Abstract: A high reliability electric power control semiconductor device with a prolonged product lifetime has been provided by successfully suppressing the metal support plate or the metal heat dissipation plate from warping due to the thermal stress during bonding so as to prevent the occurrences of cracks and gaps in the brazing fillers in the bonded layers between the metal heat dissipation plate or the metal support plate and the insulation plate in the semiconductor device comprising the semiconductor elements, metal heat dissipation plate, thermal stress buffer, insulation plate, and the metal support plate, wherein at least one of the metal heat dissipation plate and the metal support plate comprises a copper alloy of which a softening temperature at which a hot hardness of which becomes 1/2 of the hardness at the room temperature is 350.degree. C. or more.
    Type: Grant
    Filed: December 23, 1994
    Date of Patent: April 15, 1997
    Assignees: Hitachi, Ltd., Hitachi Haramachi Electronics Co., Ltd.
    Inventors: Noboru Baba, Hisanori Okamura, Masahiko Sakamoto, Hirosi Akiyama, Ryuichi Saito, Yoshihiko Koike, Makoto Kitano, Sigeki Sekine, Hideya Kokubun, Nobuya Koike
  • Nuclear fusion reactor
    Patent number: 4690793
    Abstract: The nuclear fusion reactor of the present invention presents a new vacuum vessel for enclosing plasma particles where a reactor wall exposed to the above plasma particles has a piled structure. A plurality of heat-resisting ceramic tiles are metallurgically bonded to a metal-base body having a cooling means through a brazing material. The ceramic tiles are preferably composed of sintered silicon carbide of high density and containing a little beryllium oxide between the boundaries of crystal grains.
    Type: Grant
    Filed: February 17, 1984
    Date of Patent: September 1, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Hisanori Okamura, Kunio Miyazaki, Hirosi Akiyama, Shinichi Itoh, Tomio Yasuda, Kousuke Nakamura, Yukio Okoshi, Mutuo Kamoshita, Akio Chiba
  • Production method of thin film magnetic head
    Patent number: 4685014
    Abstract: In producing a magnetic head by thin film technique, a magnetic film is formed on an insulating member covering coil conductor films after the surface of the insulating member is flattened. After a flattening coating is formed on the insulating member, the flattening coating as well as the insulating member are etched by plasma-assisted etching technique in order to flatten the surface.
    Type: Grant
    Filed: July 29, 1982
    Date of Patent: August 4, 1987
    Assignee: Computer Basic Technology Association
    Inventors: Masanobu Hanazono, Shinichi Hara, Hirosi Akiyama, Masaaki Hayashi, Harunobu Saitoo, Takumi Kurisu
  • Ceramic composite article
    Patent number: 4636434
    Abstract: A carbon film is formed on a ceramic element, or a metal film is formed on the carbon film, and subsequently the ceramic element is bonded to another ceramic or metal element, thereby forming a composite article. The composite article has a high bonding strength and is hardly fractured at joint. Ceramic articles having a surface coating of a hard carbon film or a hard carbon film containing metal grains can also be formed by this process.
    Type: Grant
    Filed: December 7, 1984
    Date of Patent: January 13, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Hisanori Okamura, Hirosi Akiyama, Mutuo Kamoshita, Kunio Miyazaki