Electrostatically actuated microelectromechanical deformable mirrors

The mechanics of the mirror was analyzed using the finite element package ANSYS to show the effect of the structural parameters and actuated voltages on the deflection of the actuator. A lumped parameter model was developed for predicting the transient motion of mirrors, taking into account electrostatic and tensile forces and viscous air damping via squeeze film theory. The results show that the elastic membrane thickness, actuator span and gap spacing have a strong effect on the deflection, the actuator undergoes the deflection increasing nonlinearly at voltages below pull-in voltage and snap through instability at voltages above pull-in voltage when subjected to a voltage ramp, the re-set time and repeatability are attractive when the actuated voltage is set to zero.