Ultrasonic Phased-Array Sensor Using PZT Thin Film and Three-Dimensional Object Detection Using BBD Combined with BBD Delay Circuit

다국어 초록 (Multilingual Abstract)

Arrayed ultrasonic microsensors using piezoelectric PZT (Pb(Zr,Ti)O3) thin lms on micromachined
silicon diaphragms have been fabricated and combined with BBD (Backet Brigade Device)
for signal processing. The ultrasonic sensors are designed to compose an electrical phased array for
three-dimensional object detection in air. The resonant frequencies of the elements were scattered
in the error range of 12 % and the objects could not be detected due to the beat in the sum of
delayed element waveforms. Each element has been tuned by adequate poling less than 10 V to
make its resonant frequency equal to a center value. The frequency scattering was reduced within
the range of 2 % and the tuned array could give the objects by summing up of the delayed signals.
Three-dimensional object detection has been demonstrated using the tuned sensor combined with
the BBD delay circuit.4