Flexible Capacitive Proximity Sensor Based On Patterned Electrodes

Proximity sensing has great potentials in intellisense applications.For example,when an intelligent robot grabs objects or avoids obstacles,proximity sensors will provide information about the external environment.At present,there are many mature proximity sensors,which are widely used in intelligent home,industrial production,anti-theft system,measurement technology and other fields.However,traditional proximity sensors are usually based on metal materials,which are too hard to be applied to curved surfaces or environments requiring high flexibility.To address this issue,intensive efforts have been devoted to develop flexible proximity sensors based on the recent progress in flexible electronics,materials engineering and fabrication technology,which provides a solid technical foundation for the research.This work focuses on the flexible capacitive proximity sensor suitable for close sensing.Recent researches usually characterize the capacitance of the device or relative capacitance change rate?C/₀ with the change of distance simply.And other common sensor performance parameters such as sensitivity and hysteresis are not sufficiently discussed.Based on the principle of capacitive proximity sensors,namely the fringing field effect of the capacitor,we designed a flexible patterend electrodes-based proximity sensor and analyzed the enhancement effect of the graphic electrodes on the fringing field based on COMSOL Multiphysics.Moreover,the working model of the capacitive flexible proximity sensor was established to predict the performance of devices,and study whether the graphic electrodes can improve the sensitivity.In addition,a proximity sensor with spiral wire electrodes was prepared with the relative change rate of capacitance?C/₀ of 15.3%and the sensitivity as high as 0.187 p F/mm.We also characterized device performance in terms of detection range,hysteresis,and response time.In the first chapter,we will analyze the applicability of various types of proximity sensors in close sensing and introduce the development history and current status of flexible capacitive proximity sensor.The second chapter introduces the simulation experiment of patterned electrodes using COMSOL software.And the spiral electrodes-based proximity sensor with in-depth research in performances is presented the third chapter.Finally,we will draw a summary and propose some development prospects about flexible capacitive proximity sensors.