Authors: X.T. Wu, Z.X. Xiao, J. Zhe and K.R. Farmer
Affilation: New Jersey Institute of Technology, United States
Pages: 382 - 385
Keywords: electrostatic micro mirror, electrostatic micro actuator, travel range, series capacitor loop, pull-in
This paper demonstrates two passive feedback methods to obtain increased travel range in electrostatic micro actuators directly in the electrostatic domain. The first method is modeled as a series capacitor loop in which an integrated fixed capacitor is utilized as a voltage divider to control the effective actuation voltage across the variable capacitor/actuator, and the resulting increased travel ranges are obtained up to 100% and ~70% full scale for vertical Z micro actuators and torsion full-plate micro actuators, respectively. The second method utilizes negative feedback due to coulombic repulsion force between the net oxide charges that exist in two oxide layers placed between the actuator electrodes, and the resulting travel range is found to be 62% for a fabricated three-spring device.