Patent ID: 8126171

Claim:
An ultrasonic speaker comprising: an electrostatic ultrasonic transducer that includes a first electrode that has through-holes, a second electrode that has through-holes, and a vibrating membrane that is disposed such that the through-holes of the first electrode and the through-holes of the second electrode form a pair, interposed between the first electrode and the second electrode, and having a conductive layer applied with a direct current bias voltage, the first electrode and the second electrode each having counter electrode portions that are formed in the through-holes to face the vibrating membrane, a modulated wave obtained by modulating a carrier wave in an ultrasonic frequency band with a signal wave in an audible frequency band being applied between the pair of electrodes; a signal source that generates the signal wave in the audible frequency band; a carrier wave supply unit that generates the carrier wave in the ultrasonic frequency band and outputs the carrier wave; and a modulating unit that modulates the carrier wave with the signal wave in the audible frequency band output by the signal source, wherein the electrostatic ultrasonic transducer is driven by a modulated signal that is applied between the first electrode and the second electrode and an electrode layer of the vibrating membrane and is output from the modulating unit.