ELECTROSTATIC ULTRASONIC TRANSDUCER, ULTRASONIC SPEAKER, AUDIO SIGNAL REPRODUCTION METHOD, ELECTRODE MANUFACTURING METHOD FOR USE IN ULTRASONIC TRANSDUCER, ULTRASONIC TRANSDUCER MANUFACTURING METHOD, SUPERDIRECTIVE ACOUSTIC SYSTEM, AND DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an electrostatic ultrasonic transducer of a Push-Pull type which can generate a stronger ultrasonic wave under the same drive conditions as with others and which increases the efficiency of conversion from electrical energy to acoustic energy.

SOLUTION: An electrostatic ultrasonic transducer includes a first electrode 10A in which a plurality of holes are formed; a second electrode 10B in which a plurality of holes are formed and which is used in pair with the first electrode; a vibration film 12 sandwiched between the pair of electrodes, having an electrode layer 121, and applied with a DC bias voltage; and a retention member that holds the pair of electrodes and the vibration film. In the transducer, an AC signal is applied between the pair of electrodes. The pair of electrodes each have a thickness t of about (λ/4)n, whereλdenotes the wavelength of the ultrasonic wave, and n denotes a positive odd number.

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