基于径向磁场分布的MEMS双轴电磁驱动微镜研究

Research on MEMS biaxial electromagnetic micromirror based on radial magnetic field distribution

介绍了一种适用于激光雷达应用场景的电磁驱动式双轴MEMS微镜,并设计一种新颖的径向磁场致动系统.利用图案化单匝电镀铜线圈和同心永磁体组件形成的径向磁场作用,驱动直径2.6 mm的大孔径双轴微镜偏转.在此工作原理基础上,理论分析和有限元仿真了不同弹性扭转梁结构的驱动位移响应输出等力学特性,提出选用大位移响应量的蛇形折叠梁作为微镜器件的外扭转轴的结构模型,并对永磁体组件耦合的磁场进行研究分析、仿真,实现驱动线圈处获得最大磁场强度.所设计的微镜水平谐振频率和竖直谐振频率可达3376.2 Hz和419.46 Hz,共振态下的水平光学偏转角度和竖直偏转角度分别约为±25.2°和±17.4°,满足MEMS激光雷达对光束扫描器件的大尺寸镜面和广扫描视场范围的需求.

An electromagnetically actuated dual-axis MEMS scanning micromirror for lidar applications is introduced,besides a novel radial magnetic field actuation system is designed.The dual-axis scanning micromirror with large aperture which the plate size of 2.6 mm in diameter was realized utilizing patterned single-turn electroplated copper coils,which combined with a concentric permanent magnet assembly forming radial magnetic field.Based on the basic of this working principle,the displacement response outputs of different torsion beam structures were compared by theoretical analysis and finite element simulation.The serpentine elastic beam was chosen as the external torsion axis of the micromirror device because of its large displacement output.The coupling magnetic field of the permanent magnet assembly was analyzed and simulated to achieve the maximum magnetic field intensity at the coils.Horizontal resonance frequency of the presented micromirror was 3376.2 Hz and vertical resonance frequency was 419.46 Hz,in addition,maximum deflection angle of approximately±25.2°in horizontal direction and about±17.4°in vertical direction were achieved at resonance.The design of the micromirror meets the requirements of MEMS lidar for large mirror size and wide scanning field of view.