Patents by Inventor Shinichi Shirasu

Shinichi Shirasu 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: 4397562
    Abstract: A novel type of digital-to-analog converter circuit is disclosed for an electronic timepiece having a speech synthesizing capability. The converter circuit utilizes pulse width modulation to form a train of pulses in response to successive digital signals which specify amplitude and polarity values for synthesizing speech, with the pulse widths being determined in accordance with the digital signal values. By filtering out the unwanted high frequency components of this pulse train, speech signals can be synthesized through an audio transducer. Such a digital-to-analog converter is capable of operating in a satisfactory manner at low levels of supply voltage, and has a very low power consumption.
    Type: Grant
    Filed: February 24, 1981
    Date of Patent: August 9, 1983
    Assignee: Citizen Watch Company Limited
    Inventor: Shinichi Shirasu
  • Patent number: 4023890
    Abstract: A digital display device for forming one or more electro-transmissive display patterns, which comprises a pair of oppositely disposed electrodes to which a signal is supplied for energization. Each of the electrodes includes a number of electro-conductive sections which are disposed with a lower distribution density at the central portion and with a higher distribution density at the contour portion. This mode of distribution of the sections gives an equivalent visual contrast to the situations in which all the sections are disposed with a uniform distribution while at the same time reducing the power consumption rate.
    Type: Grant
    Filed: July 31, 1975
    Date of Patent: May 17, 1977
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Shinichi Shirasu, Yasushi Nomura