Thermal actuated passive bistable MEMS switch

Abstract

A completely passively operating micro-mechanical switch is presented. The switch composes of a thermal actuator and a curved bistable beam. The actuator comprises V-shaped beams and a lever transmission. It is designed to operate passive only relying on the thermal expansion of the active material (electroplated Ni) and the temperature changes of the surrounding environment, where the temperature ranges from 40°C up to +50°C. The actuator exhibits a temperature dependent deflection sensitivity of 0.9 μm/K and sufficient force to push the bistable beam into is secondary position. Both subsystems are connected via a latching mechanism. A temperature difference of at least 35 K is required for activation of the switch. A self tailored measurement setup is used to quantify the temperature dependent deflections by means of an optical principle. The measured results are in good agreement with results of numerical simulations and analytical models.