Novel electrothermal bimorph actuator for large out-of-plane displacement and force

This paper presents a novel concept and experimental validation of an electrothermal bimorph structure for out-of-plane actuation that exploits the polymer constraint effect. The proposed concept is capable of generating large out-of-plane displacements and forces at a low driving voltage and a low actuation temperature. A downward displacement up to 31 μm is measured at only 5 V driving voltage and 46 mW power consumption. The actuator stiffness is measured to be 75 N/m, thus the corresponding calculated out-of-plane force is 2.3 mN. The maximum actuation temperature during the measurement is 100 °C (80 °C change). A 25 Hz response frequency is measured by monitoring the resistance change due to the temperature variation.