Patents by Inventor Kohei Hirukawa

Kohei Hirukawa 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).

  • Piezoelectric audible sound generator
    Patent number: 4393373
    Abstract: A piezoelectric audible sound generator having a feedback type piezoelectric transducer, an amplifier, and a phase compensator for adjusting the phase shift due to the combination of a bias resistance of the amplifier and equivalent capacitance of the piezoelectric transducer.
    Type: Grant
    Filed: March 16, 1981
    Date of Patent: July 12, 1983
    Assignee: Fuji Electrochemical Co., Ltd.
    Inventors: Michihiro Torii, Kohei Hirukawa, Hiroshi Urata, Shinichi Suzuki
  • H-Type ceramic resonator
    Patent number: 4368402
    Abstract: An H-type ceramic resonator having two resonating leaves, a connecting leaf for bridging the two resonating leaves to form an H-shape, and electrodes disposed on at least both surfaces of the resonating leaves. The resonator has a dimensional relationship which falls within the following equities:B.sub.2 /B.sub.3 =4 to 6,B.sub.1 /B.sub.3 =2 to 4, andL/B.sub.1 =5 to 6wherein L is a length of each of the resonating leaves, B.sub.1 is a width of each of the resonating leaves, B.sub.2 is a distance between the two resonating leaves, and B.sub.3 is a width of the connecting leaf.
    Type: Grant
    Filed: July 1, 1981
    Date of Patent: January 11, 1983
    Assignee: Fuji Electrochemical Co., Ltd.
    Inventors: Michihiro Torii, Kohei Hirukawa, Ryoji Tsuchiya, Hiroshi Urata, Isamu Sasaki, Kunio Esaki