Electrostatic Comb Drive Levitation And Control Method

This paper presents the theory, simulation results, and experimental study of the levitating force (normal to the substrate) associated with Interdigitated capacitor (electro static comb) lateral actuators. For compliant suspensions, normal displacements of over 2 /spl mu/m for a comb bias of 30 V are observed. This phenomenon is due to electrostatic attraction induced on top of the suspended structure. By electrically lsolating alternating drive-comb fingers and applying voltages of equal magnitude and opposite sign, levitation force can be reduced by an order of magnitude, while reducing the lateral drive force by less than a factor of 2. The levitation theory incorporates electrostatic simulation results, and agrees well with experimental data.