Patent ID: 8666094

Claim:
An ultrasonic speaker, comprising: an electrostatic-type ultrasonic transducer which includes a first electrode having through holes, a second electrode having through holes, and an oscillation film which is disposed such that each of the through holes of the first electrode is paired with the corresponding through hole of the second electrode, is sandwiched between a pair of the first and second electrodes, and has a conductive layer to which direct current bias voltage is applied, wherein modulation waves produced by modulating carrier waves in an ultrasonic frequency band by signal waves in an audio frequency band are applied between a pair of the electrodes, and the through holes are resonance pipes that increase sound pressure; a signal source for that produces signal waves in an audio frequency band; a carrier wave generating source that produces and outputs carrier waves in an ultrasonic frequency band; and a modulator that modulates the carrier waves by the signal waves in the audio frequency band outputted from the signal source, wherein the electrostatic-type ultrasonic transducer is actuated by modulation signals outputted from the modulator and applied between the electrode layer of the oscillation film and a pair of the electrodes, and wherein an acoustic reflection plate that reflects ultrasonic waves released from respective openings of a back face of the electrostatic-type ultrasonic transducer to a front face of the electrostatic-type ultrasonic transducer by routes all having the same length is provided on the back face of the electrostatic-type ultrasonic transducer.