Reducing ring-down time of pMUTs with phase shift of driving waveform

This paper proposes a method to reduce ring-down time for piezoelectric micromachined ultrasonic transducers (pMUTs) through phase shift. The proposed driving form can effectively improve the effective emission time to transmitting time (Tx time) ratio and decrease the ring-down time, which contributes to shorten the blind area in pulse-echo ultrasonic distance measurement. The phase shift method effectively restrains the pMUT's ring-down vibration within 20 nm in air and 15 nm in water swiftly. Consequently, the ring-down time can be saved from 45.9∼206 μs in air and 78.9∼130.1 μs in water respectively. The suppressed ring-down can sharpen the echo envelop for better location applications. Detection of the precise vibration stop time based on time constant of pMUTs is useful for measurement with high accuracy.