Long stroke out-of-plane actuator using combination of electrostatic and pneumatic forces

We propose an out-of-plane MEMS actuator with a large stroke length comparable to the size of the actuator itself. The proposed device is actuated by the combined forces of the electrostatic and the pneumatic forces. This combination of two independent forces enlarges a stable area during the actuation, resulting in a large stroke which is difficult to be achieved with only either force. The 3D profiling by the laser scanning microscopy confirmed the largest stroke of 103 μm was obtained with the 150-μm-diameter actuator area with the electric field of 5.8 × 10⁵ V/m (330V between the electrodes) and the air pressure of 2.0 kPa.