ACOUSTIC GENERATION METHOD AND APPARATUS USING MULTIPLE ULTRASONIC RADIATION AUTOMATICALLY SET OF RADIATION DIRECTION

摘要

PROBLEM TO BE SOLVED: To solve the problem that an acoustic signal can not be generated only in an arbitrary spatial spot since the acoustic signal is radiated as an ultrasonic wave in an ultrasonic band with amplitude modulation to generate the acoustic signal on radiation and that the direction of the radiation for reproducing the acoustic signal by using the ultrasonic wave can not be designated and set in real time based upon an external signal.;SOLUTION: The acoustic generation apparatus is provided with a means for radiating and making cross an ultrasonic wave discharging, as the ultrasonic wave, an ultrasonic radiation signal which is a single-sideband signal or a double-sideband signal modulating an amplitude of an acoustic signal and suppressing a carrier, and an ultrasonic wave of a single frequency while using the fact that the acoustic signal is generated based upon non-linearity when propagating an ultrasonic signal in the air, to generate acoustics as component signals of a frequency difference between both the ultrasonic waves, and a means for changing, in real time, a crossing point of the ultrasonic waves to an arbitrary position based upon an acoustic generation position signal inputted from the outside.;COPYRIGHT: (C)2004,JPO