Resistive-Capacitive Dual-Modal Synergistic Flexible Pressure Sensor With Triangular Prism Microstructures

Existing flexible pressure sensors are often limited in applications due to inheriting the disadvantages of the adopted transduction mechanism, multimode sensing solutions are expected to overcome this limitation. Here, we report a novel design approach for integrating resistor and capacitor into flexible pressure sensor rather than simply stacking them, which will enable the proposed device to feature the low detection limit of capacitive sensor and the wide response range of resistive sensor. The electrodes of a capacitor are designed with copper foil and conductive graphite paint film, and the dielectric layer is composed of an elastic body with a prismatic structure. Furthermore, the conductive silver paint film is attached to the surface of the prismatic structure for forming a low-resistance conductor, which can trigger electrical shorting effect in conjunction with the conductive graphite paint film. It is regarded as the transducing mechanism of the designed resistive sensor. Experimental results indicate that the developed device has a low response limit of 0.006 N and a working range that extends to 20 N. The response times for the capacitive and resistive modes are 37 and 38 ms, respectively, showcasing excellent repeatability in response. Therefore, the developed device can respond to high-frequency impacts, such as the rebound phenomenon of a glass ball in free fall. The proposed dual-mode sensing design approach not only facilitates integration but also broadens the application scenarios for the developed devices.