Low-Cost, Flexible Annular Interdigital Capacitive Sensor (Faics) with Carbon Black-Pdms Sensitive Layer For Proximity and Pressure Sensing

Abstract

In this paper, we proposed a flexible and wearable sensor integrating an annular interdigital electrode and a carbon black-PDMS sensitive film with micro-pyramid array. The device has two shielding layers and a sensing layer, which are fabricated by the flexible PCB process to realize low-cost and rapid manufacturing. The proposed annular interdigital structure and the shielding layer significantly improves the capacitance value and sensing sensitivity compared with the conventional rectangular interdigital structure. The sensitive film using carbon black (CB)-PDMS hybrid material greatly increases the sensitivity of the sensor as well, resulting from higher conductivity of the CB. Furthermore, we have developed a multi-channel acquisition system for capacitive sensors array, which realizes multi-channel simultaneous sampling. The FAICS demonstrates a piecewise linear pressure sensing characteristics, and can realize stable proximity and pressure sensing, as well as the functions of effective touch sensing, sliding gesture recognition, and pressure distribution test.