Hidden Dual Layer Comb Drive MEMS Scanning Mirror Array

To address the common shortcomings of conventional electrostatic-driven MEMS scanning mirror arrays, including low fill factor and low resonant frequency, a two-dimensional MEMS scanning mirror array featuring a high fill factor and high resonant frequency is developed. This scanning mirror employs a concealed comb-drive technique, featuring a nested double-layer comb structure for its outer drive unit. Through theoretical analysis, a drive model for the scanning mirror was constructed, and its static and dynamic characteristics were simulated using COMSOL software. Theoretical results indicate that while achieving a high fill factor of 91%, under a 30 V sinusoidal voltage drive, the inner and outer axes of this scanning mirror exhibit resonant frequencies of 9364.9 Hz and 13262 Hz respectively, corresponding to deflection angles of 4.1° and 6.3°. Analysis of the array’s characteristic frequencies and static response verifies that the array exhibits good consistency. Furthermore, a fabrication process was designed for this device, and its sensitivity to process errors was analyzed, providing a theoretical reference for the application of electrostatic MEMS micromirror arrays in scanning imaging.