Fully flexible large-area MEMS-based triaxial force sensor compatible with flat panel display manufacturing - Microsystems & Nanoengineering

The research describes a fully flexible, large-area MEMS-based triaxial force sensor designed to be compatible with flat panel display manufacturing. It explains how shear forces create opposing changes in capacitance—one decreases while the other increases—enabling a differential readout. The paper reports that a 3D FEM model captures initial deflection caused by fabrication-induced residual stresses, illustrated with an embedded “butterfly” MEMS structure where wings bend upward and a central portion deflects downward. Optical microscopy using interference fringes and profilometry measurements using an optical profilometer (including a Lyncée Tec Digital Holographic Microscope) are used to characterize the deformed configuration. Experiments include pointwise mechanical load testing with a vertical force on a wing corner tip in the 10–90 μN range, with displacement detected via a DektakXT stylus profilometer, and the measured force–displacement curve is reported to match the FEM results. Electrostatic response measurements are carried out with a Keysight E4980A Precision LCR Meter by quantifying capacitance dependence on voltage.