非正交二维MEMS倾斜镜的研制

Development of non-perpendicular 2D MEMS tilt mirrors

为提高传统二维倾斜镜在非正交方向上的光转换效率,设计并加工了一种转轴非正交二维MEMS倾斜镜。倾斜镜上电极非对称地固定在基底上,通过控制上、下电极的加电方式实现倾斜镜在两个非正交轴上的偏转变形。采用三层膜的结构设计,消除了上电极应力变形对镜面平整度的影响。通过在上电极加工微小突起,减小上下电极的重叠面积,避免了倾斜镜的吸合失效;另外,上、下电极仅在其边缘处重叠,确保了静电力的有效利用。研制的倾斜镜驱动电压低,在3.5 V的电压下可实现绕水平X轴0.16°、绕倾斜Y轴0.03°的偏转,Y轴与X轴成145.37°夹角。倾斜镜结构简单,可实现绕两个非正交转轴的偏转,空间适应性好,且有效避免了静电吸合对镜子的损坏。

To improve the efficiency of optical conversion and spatial adaptability of conventional 2D tilt mirrors,non-perpendicular 2D MEMS tilt mirrors were presented in this paper.The designed mirrors were fabricated by PolyMUMPS process and their upper electrodes were asymmetrically fixed on a substrate.The deformation of mirrors tilted around two non-perpendicular axes were controlled by applying voltages.By constructing mirrors with three-layer membranes,effects of the upper electrode＇s deformation on the flatness of the mirror surfaces were eliminated.By fabricating dimples on the upper electrode and reducing the overlapped area of mirrors＇ electrodes on the edges of the upper electrode,the damage caused by the pull-in effect was eliminated.Furthermore,the designed electrodes made sure that forces produced by the applied voltages would produce large moments.The developed mirrors lower the working voltages,their tilting angles around X-and Y-axes are 0.16° and 0.03° at 3.5 V,respectively,and the angle between X axis and Y axis is 145.37°.It concludes that the mirrors can rotate around two non-perpendicular axes independently,and its advantages are simple structures and good spatial adaptability.