Patents by Inventor Katsuichi Ohsawa

Katsuichi Ohsawa 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).

  • Optical transmitter
    Patent number: 7298977
    Abstract: The present invention is intended to prevent a light-emitting diode from emitting light continuously in the case when the level at an input terminal is fixed high because of software or the like and to avoid various problems, such as battery exhaustion and breakdown of the light-emitting diode, in PDAs, cellular phones, etc. For these purposes, a high-pass filter 21 for passing the high-frequency components of an optical transmission input signal having a pulse waveform and a binary circuit 22 for binarizing the output signal of the high-pass filter 21 so as to be returned to a pulse waveform are provided in the preceding stage of a light-emitting device driving circuit 23 for driving a light-emitting diode 8 for optical transmission.
    Type: Grant
    Filed: November 28, 2002
    Date of Patent: November 20, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuichi Ohsawa, Toyoyuki Shimazaki, Tetsuo Chato, Yuzo Shimizu, Kenji Imaizumi
  • Optical transmitter
    Publication number: 20050063710
    Abstract: The present invention is intended to prevent a light-emitting diode from emitting light continuously in the case when the level at an input terminal is fixed high because of software or the like and to avoid various problems, such as battery exhaustion and breakdown of the light-emitting diode, in PDAs, cellular phones, etc. For these purposes, a high-pass filter 21 for passing the high-frequency components of an optical transmission input signal having a pulse waveform and a binary circuit 22 for binarizing the output signal of the high-pass filter 21 so as to be returned to a pulse waveform are provided in the preceding stage of a light-emitting device driving circuit 23 for driving a light-emitting diode 8 for optical transmission.
    Type: Application
    Filed: November 28, 2002
    Publication date: March 24, 2005
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuichi Ohsawa, Toyoyuki Shimazaki, Tetsuo Chato, Yuzo Shimizu, Kenji Imaizumi