Ultra‐thin smart electronic skin based on hybrid system‐in‐foil concept combining three flexible electronics technologies

Abstract

Flexible electronics combined with new materials and fabrication processes offer unique characteristics such as mechanical flexibility, thin‐form factor, large area scaling feasibility, and adaptability to irregular surfaces. In this work, a smart electronic skin adopting the hybrid system‐in‐foil concept is designed to monitor the uniaxial bending of a robotic gripper. The newly designed smart skin contains an array of printed strain gauges, organic thin‐film transistor (TFT) addressing circuits and a 20 μm ultra‐thin silicon readout chip, all integrated on the same polymeric foil. The silver‐ink printed strain gauges achieve a relative resistance sensitivity Δ R / R of 2% and a gauge factor of 2. In addition, the organic TFT multiplexer containing a three‐stage shift register and analogue switches operate at a frequency of 100 Hz and a supply voltage of 3 V. The ultra‐thin silicon chip provides the functions of system control, strain gauge readout, analogue‐to‐digital conversion and serial communication.