A pulse width modulation controlled bistable MicroElectroMechanical system

This paper describes a pulse width modulation controlled bistable microelectromechanical system (MEMS). A bistable mechanism offers two distinct equilibrium states without requiring input power to stay in either of the stable states. The state of the single digital input bistable MEMS device described in this paper is determined by the duration of the input pulse to the actuators. Applications of bistable mechanisms include MEMS relays and optical switches. By using a single digital input and pulse width modulation control, this design allows for easier integration with digital drive circuitry. This mechanism is able to use a single digital input because it utilizes the difference in time constants between two perpendicular actuators. The design consists of two actuators situated perpendicularly to each other, which are both connected to a hook shape. This hook latches with an opposing hook, which anchored to the substrate, when an input pulse of sufficient duration is applied to the actuators. The hooks will disengage when an input pulse of appropriate duration is applied to the actuators. Operating principles and physical theory behind the actuation technique will be discussed in detail. As well, the current state of this research and an analysis of a prototype device fabricated using MUMPs® will be discussed.