Electric directivity scanning using arrayed ultrasonic transmitter/receiver with parylene diaphragm

This paper reports the development of an arrayed device, which can act as both transmitter and receiver for ultrasonic pulses in the air. The device is composed of micromachined capacitive structures with parylene diaphragms, each of which can generate large sound pressure and realize high sensitivity based on the non-brittle and flexible characteristics of polymer parylene. By setting a delay time for each adjacent diaphragm, the control of transmitting and receiving directivity is successfully achieved.