Abstract
Arrayed ultrasonic transducers using the piezoelectric thin film (lead-zirconate-titanate film: Pb(Zr0.52Ti0.48)O3 : PZT) having multilayer diaphragm structures are fabricated. The variation in resonant frequencies of conventional ultrasonic sensors is 7.3% in standard deviation, although those have the same structure. In order to reduce the variation of resonant frequency, membrane is coated by amorphous fluorocarbon polymer (FC) film (CYTOP, AGC). The variation in resonant frequencies of new ultrasonic sensors is 2.3% in standard deviation. The resonant frequency and Q-value and sensitivity of new ultrasonic sensors are estimated to be on the order of 56.9kHz and 28.3 and 114 μV/Pa, respectively. This amorphous fluorocarbon polymer film is effective for improvement of reception characteristic of ultrasonic sensor. This ultrasonic micro array sensor using the amorphous fluorocarbon polymer film is shown to be useful for three-dimensional object detection system.
