基于微机电系统(MEMS)技术微加工工艺,提出了一种新型分立倾斜式变形镜(DM)设计,并加工制作了3×4变形镜阵列。该结构每个镜面单元对应一个驱动器,实现了连续面形的分立驱动,并且可有效释放工艺过程中产生的残余应力,从而降低镜面的翘曲。基于弹性理论对该变形镜的电压位移关系以及谐振频率进行了数值计算,并利用有限元软件对其进行了仿真,同时采用光学轮廓仪对样品进行了测试。实验结果表明,所制作的变形镜阵列可实现平移和倾斜运动,在3.75 V电压下可达到0.76μm的行程,与理论分析和模拟仿真结果一致。与传统分立倾斜式变形镜相比,该新型分立倾斜式变形镜具有较低的驱动电压、较少的驱动器数量,适用于集成度高且与集成电路(IC)单片集成的变形镜设计。
A new segmented tip-tilt deformable mirror(DM) based on surface micromachining process is proposed,a mirror array with 3×4 elements is fabricated.In this new structure every mirror suface has one only actuator so that the mirror array has a continuous surface topography,and the residual stress in the fabrication process can be effectively released with a result that the curl of the surface is reduced.The resonance frequency and the relationship between displacement and voltage are calculated based on the theory of elasticity and simulated based on a finite elements analysis(FEA) software.Then the fabricated device is tested by an optical profiler.Experimental results indicate that the actuated array has a piston-tip-tilt(PTT) motion,and the mirror has a stroke of approximately 0.76 μm under 3.75 V driving voltage,which is coincident with the theoretical analysis.Compared with previous reported segmented tip-tilt DM,this new structure has a lower working voltage and a fewer amount of actuators,and provides a possibility of integrating a large-actuator-count DM with integrated circuit(IC) on one chip.