提出了一种利用热应力改变镜面曲率的可调焦微光学自适应微镜。与传统自适应微镜相比,采用该原理制作的微镜具有驱动电压低和驱动力较大的优点,而且制作简单。以硅为基底进行了表面热氧化、光刻显影、HF酸刻蚀、KOH湿法刻蚀,溅射铝膜等微加工工艺的研究,获得硅铝双金属可调焦微反射镜4×4阵列,单元尺寸3 mm×3 mm,单晶硅基底厚60 μm,硅表面溅射的铝膜厚150 nm。该微镜的镜面填充率为100％,可变形镜面占总镜面面积的79％。利用激光波面干涉仪对可调焦微反射镜的动态性能进行了测试。实验表明,该微镜可产生单向连续变形,最大变形量15.8 μm, 非线性滞后27％,工作电压0～2.5V,可调焦范围∞～0.036 m。

A novel adjustable focal-length optical adaptive micro-mirror based on bi-mental effect is presented. Compared with traditional deformable micro-mirror, micro-mirror fabricated by this method has the advantage of low driving voltage and large driving force. Besides,it is easy to be fabricated. Micro-machining processes such as oxygenation,photolithography, chemical etching and sputtering are experimented. A 4×4 bi-metal adjustable focal-length micro-mirror arrays have been completed. Each unit has an area of 3 mm×3 mm with the thickness of silicon 60 μm and aluminum film 150 nm. Deformable mirror area covers 79% of the total mirror area which is 100%. Dynamic performance of adjustable focal-length micro-mirror is tested using laser wave-front interferometer. Experiment results demonstrate that the micro-mirror can produce uni-directional continuous deformation with the maximum deformation of 15.8 and nonlinearity lag of 27%。It can work at 0～2.5 V with an adjustable focal length ranging from ∞ to 0.036 m.