Dynamic Behavior Investigation of the Piezoelectric PVDF for Flexible Fingerprint

Abstract

ABSTRACTThe paper reported a novel flexible concept for acquiring the fingerprint that based on the piezoelectric PVDF (polyvinylidene fluoride) was integrated into the flexible polyimide substrate to form the fingerprint. In this study, it focused on the array PVDF fabrication and dynamic control circuit to read pressure signal for fingerprint identification. The fabrication of PVDF powder was melt at 180°C, pressed under 2 tons and subsequently quenched at 10°C/min to form the PVDF films. Next the PVDF films were put into the oven at different temperatures for 40 minutes to stretch 4 times from its original length. As for the dynamic control, the sensing circuit was presented two parts, one is charge amplifier and the other is capacitance detect by using frequency oscillator. We demonstrated that the dynamic pressure measurement of PVDF could achieve fingerprint acquisition. Experimental results showed the response speed of sensing is as fast as 5 ms. Therefore, the aim of this study is to speed up the technology for promoting the flexible fingerprint.