Patents Examined by Donna V Lu
  • Patent number: 10817114
    Abstract: A capacitance detection device includes a first voltage output circuit configured to output a first alternating current voltage supplied to a shield electrode provided proximate to a detection electrode, a second voltage output circuit configured to output a second alternating current voltage whose frequency and phase are the same as that of the first alternating current voltage and whose amplitude is less than that of the first alternating current voltage, and a current output circuit configured to output a driving current Is to the detection electrode so that the difference between the voltage of the detection electrode and the second alternating current voltage becomes smaller, and output a detection signal corresponding to the driving current. The second voltage output circuit outputs a second alternating current voltage whose amplitude is adjusted so that the driving current in the absence of the object proximate to the detection electrode.
    Type: Grant
    Filed: June 14, 2019
    Date of Patent: October 27, 2020
    Assignee: ALPS ALPINE CO., LTD.
    Inventors: Kiyoshi Sasai, Tatsumi Fujiyoshi, Shinichi Sagawai