MEMS Scanning Mirror with High Resonant Frequency Comb Axisymmetric Structure

Aiming to address the drawbacks of electrostatic-driven MEMS scanning mirrors, such as low resonant frequency and high driving voltage, a novel two-dimensional MEMS scanning mirror with improved resonant frequency and reduced driving voltage is proposed. The scanning mirror adopts an interleaved vertical comb structure with axisymmetric distribution. Through the theoretical analysis of the device, the theoretical model is established. COMSOL simulation software is employed for static and dynamic analysis to verify the performance of the scanning mirror. The results demonstrate that the comb axisymmetric structure can provide greater driving torque during deflection, while avoiding the interference caused by the unbalanced motion of the traditional comb. Under the sine wave voltage of 12 V and 16 V, the resonant frequencies of the fast axis and the slow axis are 11657 Hz and 6122.4 Hz, respectively, and the corresponding mechanical deflection angles are 5.9° and 6.6°. Furthermore, a significant disparity between the resonant frequencies of both axes effectively suppresses mutual interference between their respective motion states. Finally, a set of fabrication processes suitable for this device has been designed.