Flexible Membrane Impact Sensor via Thick Film Method

Abstract

A piezoresistive based impact or contact sensor on flexible polyimide substrate is constructed with pressure sensitive electrically conductive polymer composites with a Shore “A” hardness of 78 and nano silver inks using thick film method. Optimum design layouts of the sensor’s electrode pair spacing of the polymer based impact sensor are modeled. The transducer resistance change has an exponential decay relationship upon external impulse activation. A shock and vibration test bench is build to test the fabricated impact sensors. The loading time dependence of the conductive polymer transducer electrical resistance at constant pressure is investigated. The conductive polymer transducer electrical resistance response is found to be stabilized after about 6 sec. A theory is also formulated to explain the observed negative exponential response. An environmental chamber is used to test the conductive polymer transducer’s thermal response in the cycling range of 25oC to 80oC.

Keywords

• Flexible substrate
• Impact sensor
• Membrane