Patents by Inventor Masaoki Ishikawa

Masaoki Ishikawa 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: 4195283
    Abstract: An integrating type analog-to-digital converter is provided which finds in the first conversion cycle an analog-to-digital conversion value including a possible conversion error resulting from offset voltage applies an unknown voltage to an inverting amplifier in a second conversion cycle to find an analog-to-digital conversion value including a possible conversion error like the unknown voltage so polarity-inverted, and finds a sum of both the conversion values to thereby obtain a correct digital-to-analog conversion value free from conversion errors resulting from offset voltage etc. of an integrator. N reference voltage is overlapped with respect to the unknown voltage and conversion around zero is continuous. The converter permits a bipolar operation using a signal-polarity reference voltage.
    Type: Grant
    Filed: August 1, 1978
    Date of Patent: March 25, 1980
    Inventor: Masaoki Ishikawa
  • Patent number: 4048646
    Abstract: A dual-gate Schottky barrier gate field effect transistor is provided with an intermediate electrode between a first and a second gate electrode. This intermediate electrode forms an ohmic contact with a semiconductor substrate of the transistor. The transistor is produced by etching a first film formed on a planar surface of the substrate by the use of a pair of mask pieces to leave a pair of gate electrodes narrower than the mask pieces and projecting a metal capable of forming an ohmic contact with the semiconductor towards the planar surface perpendicularly thereof. The projected metal provides source and drain electrode on both sides of the gate electrode pair and an intermediate electrode between the gate electrodes. The intermediate electrode may be left floating during operation.
    Type: Grant
    Filed: February 25, 1976
    Date of Patent: September 13, 1977
    Assignee: Nippon Electric Company, Limited
    Inventors: Masaki Ogawa, Takashi Furutsuka, Masaoki Ishikawa
  • Patent number: 3994758
    Abstract: A Shottky barrier gate field effect transistor is produced by etching a first conductive film formed on a semiconductor crystal surface using a mask to leave a first conductive film area smaller than the area of the mask and projecting a second conductive material on to the surface perpendicularly thereof. The second conductive film areas thus formed and the first conductive film area serve as the source and drain electrodes and the gate electrodes, respectively.
    Type: Grant
    Filed: March 13, 1974
    Date of Patent: November 30, 1976
    Assignee: Nippon Electric Company, Ltd.
    Inventors: Masaki Ogawa, Masaoki Ishikawa