Patents by Inventor Kouji Hirayanagi

Kouji Hirayanagi 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).

  • Ultra-directional speaker system and speaker system drive method
    Patent number: 6445804
    Abstract: An ultra-directional speaker system has a speech generation means, an ultrasonic generation means, an amplitude modulation means to which the speech generation means and ultrasonic generation means are connected, an electro-acoustic transducer means which converts an ultrasonic modulated signal that is output from the amplitude modulation means to an acoustic signal, and a virtual sound source positioning means that establishes the position of a virtual sound source by detecting the position of a listener by detecting the ultrasonic waves that are output from the electro-acoustic transducer means and reflected from the listener.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: September 3, 2002
    Assignee: NEC Corporation
    Inventor: Kouji Hirayanagi