Effect of a Microstructured Dielectric Layer on a Bending-Insensitive Capacitive-Type Touch Sensor with Shielding

In this paper, a design method to develop a bending-insensitive capacitive-type touch sensor is reported. To achieve bending-insensitive properties and a shielding effect to block the parasitic capacitance, the sensor is composed of a silver nanowire-based stretchable top electrode layer, a microstructured dielectric layer, and a film-type bottom electrode layer. The stretchability of the top electrode (i.e., tension or compression according to bending) and the pitch of microstructures, which affect the performance (i.e., initial value and sensitivity) of the sensor in bending situations, are analyzed using mathematical modeling and bending tests based on two perspectives. The analysis is conducted in both bending directions, that is, inward and outward, and the differences in the performance in both directions are analyzed. The fabricated sensor is capable of measuring a wide range of pressures (up to 700 kPa) with a sensitivity of ∼0.14 MPa–1. The sensor can be successfully applied to soft robotics applications.