Multilayer Step-like Microstructured Flexible Pressure Sensing System Integrated with Patterned Electrochromic Display for Visual Detection

Flexible pressure sensors have garnered significant attention for their potential in flexible electronics and interactive devices. However, such sensing devices typically rely on external bulky equipment for data visualization, which prevents flexible electronics from becoming smaller and more portable. Herein, we report a flexible pressure sensing system that combines a pressure sensor with a patterned electrochromic display. The pressure sensing layer has convex parallel line microarray structures, which are constructed by direct ink writing (DIW) printing technology. The multilayer microstructure in every microarray unit endows our sensors with a high sensitivity of 20.25 kPa^-1, a wide linear response range up to 35 kPa, as well as excellent durability (∼5000 cycles). The electrochromic display is designed as a common cathode structure patterned via DIW printing, which exhibits fast coloring time (<0.4 s) and long-term durability (>6000 s). This work successfully demonstrates pressure visualization in human finger bending recognition and weight measurement. Moreover, this system will enhance the visualizable pressure identification capabilities of robotic hands and prosthetics, thereby offering users a more intuitive and real-time interactive experience.