MEMS dual-mode electrostatically actuated micromirror

Micromirrors based on MEMS (Micro-electromechanical Systems) technology have been widely used in light display, optical communication and other applications. In this paper, an electrostatically actuated dual-mode micromirror device is proposed. Folded beam structure is used for piston movement and straight beams are used for torsional movement. Two switches connected to bottom aluminum driving electrodes are used to control the working mode of the micromirror. Depending on the need, it can be activated to work in either piston or torsional mode. The working principle of the micromirror is analyzed. Equations are derived to predict the performance of the micromirror in both piston and torsional modes. ANSYS simulation is used to verify the vibrational modes of the dual-mode micromirror. The proposed micromirror integrates both piston and torsional functions in a single device, leading to more flexibility and better efficiency.