Highly reliable electromagnetic MOEMS scanning grating mirror based on folded torsion beam with fillet corners

Abstract

To overcome the problems of poor structural reliability, high driving voltage and small scanning angle, a novel electromagnetic MOEMS scanning grating mirror (SGM) with folded torsion beam is reported in this work. Compared with the conventional straight torsion beam, the folded torsion beam has better elastic torsion property and can effectively improve the structural reliability of the MOEMS SGM. Furthermore, the fillet structure is added to the folded torsion beam to prevent stress concentration. The stress analysis and impact resistance of the proposed MOEMS SGM are simulated by FEM (ANSYS 18.2), and the simulation results are compared with that of the MOEMS SGM without fillet structure. The stress simulation is carried out under different fillet radius of 40–70 [Formula: see text]m, the maximum stress can be reduced to 85[Formula: see text] and the stress is redistributed uniformly. Meanwhile, in the impact resistance simulation, the impact displacement can be reduced by 10.1[Formula: see text]. A prototype is fabricated and tested, it has a large mirror area of 6 mm ×7 mm. The MOEMS SGM can reach the maximum scanning half angle of [Formula: see text] at 7.63 V under resonance (@602.1 Hz), which means that the full mechanical scanning angle of the MOEMS SGM can reach [Formula: see text].