Design and simulation of MEMS-actuated adjustable optical wedge for laser beam scanners

摘要

This paper introduces both optical and mechanical design and simulation of large static deflection MOEMS actuator. The designed device is in the form of an adjustable optical wedge (AOW) laser scanner. The AOW is formed of 1.5-mm-diameter plano-convex lens separated by air gap from plano-concave fixed lens. The convex lens is actuated by staggered vertical comb drive and suspended by rectangular cross-section torsion beam. An optical analysis and simulation of air separated AOW as well as detailed design, analysis, and static simulation of comb -drive are introduced. The dynamic step response of the full system is also introduced. The analytical solution showed a good agreement with the simulation results. A general global minimum optimization algorithm is applied to the comb-drive design to minimize driving voltage. A maximum comb-drive mechanical deflection angle of 12 deg in each direction was obtained under DC actuation voltage of 32 V with a settling time of 90 ms, leading to 1-mm one-dimensional (1-D) steering of laser beam with continuous optical scan angle of 5 deg in each direction. This optimization process provided a design of larger deflection actuator with smaller driving voltage compared with other conventional devices. This enhancement could lead to better performance of MOEMS-based laser beam scanners for imaging and low-speed applications.