Threshold Voltage Model of Fast-Moving Ball Actuator

Abstract

We clarified underlying physics and thereby developed threshold voltage model of a fast-moving ball actuator (FMBA) for reflective electronic paper display. The proposed threshold voltage model starts from considering all the related forces of Coulomb force, dielectrophoretic (DEP) force, frictional force, and adhesion caused by van der Waals force, where frictional force consists of vertical Coulomb and DEP forces, buoyance, and gravity. Considering 3-dimensional geometric effect, Coulomb and DEP forces were analyzed through numerical simulations while all the remaining forces were analytically modeled. As a result, DEP force, buoyance, and gravity were concluded negligible compared to Coulomb force and van der Waals force. With the simplified threshold voltage model, the required driving voltage of 39.54 V was obtained, which matched well to the measured voltage of 40 V