Out-of-plane electrostatic microactuators with tunable stiffness

This paper reports on the development of out-of-plane electrostatic microactuators whose stiffness can be actively tuned through an integrated mechanism based on in-plane forces acting on bending flexures. The devices combine out-of-plane flexures and drives with in-plane flexures and electrodes. The out-of-plane electrodes are asymmetric interdigitated fingers obtained from a simple, stepped deep reactive ion etching process contrasting with other more complex gap-refilling approaches. The in-plane drives consist of conventional interdigitated combs.