Printed Flexible Pressure Sensor Based On The Microstructure

Recently, the novel flexible pressure sensor has attracted tremendous attentions because its high sensitive, flexible, and wearable. It is greatly expand the application fields of traditional sensors and open up a new market. For the novel sensor, How to achieve high flexibility sensing devices by structure design has attracted significant attentions. One hand, this paper aims to comprehensive and systematic study the relationship between the micro-structured of flexible sensor and its performance, and then set up the theoretical model. On the other hand, study the process of printing flexible sensor array and realize the preliminary testing of the pressure distribution. Finally, the test from "dot" to "face", "local" to the "whole" was achieved.Here, we present a flexible capacitive pressure sensor with the micro-structured electrodes and elastomeric dielectric layer by lithography wafer template. The sensor is based on the principle of the parallel plate capacitor. The micro-structured layer was prepared with different shape, length, center distance and the elastic modulus. And the effects of the different micro-structured layer on the properties of the flexible pressure sensor were investigated by combining theoretical analysis and experimental analysis. The sensing film was prepared by screen printing and its performance was studied. We developed the test software and designed the platform for testing the sensing film. Lastly the application field of the sensor was expanded.The result of paper shows that:(1) Under the condition of constant pressure, the sensitivity of sensor will be increased with the center distance increase and thickness decreases of the micro-structured layer.(2) When the elastic modulus of microstructure PDMS is 2.03 MPa, the sensitivity of sensor was 1.944 kPa-1, the response time less than 150 ms and the lag capacitance is about 0.138 pF, accounting for 6.9% of the total capacitance change.(3) We present a sensitive sensor array film by screen printing which is more simple and low-cost than traditional preparation methods. The sensing film test platform and testing system is designed so that the stress distribution can be easily tested.Finally, the applied testing shows that the prepared flexible pressure sensor could detect tiny pressure signals, such as air flow, the human body joint bending-stretching, and the distribution of the two-dimensional force. We select ITO as the transparent electrode and keep the device sensing properties to discuss the transparency of the sensor. The light transmittance of the flexible sensor with ITO electrode is about 70% and the transparent sensor has the potential to be used in the flexible capacitive touch screen and photosensitivity electronic skins filed.