变形镜支撑结构自身性能的优劣将直接影响变形镜的像差校正能力。给出一种空间相机用变形镜的结构, 结合材料属性与加工工艺, 分析了不同结构形式支撑底座的特点, 发现采用碳纤维增强复合材料(CFRP)制作的实体式结构明显优于选用钛合金制作的筋板式结构, 指出支撑底座材料的比刚度以及支撑底座与反射镜材料之间的线胀系数差别分别是影响变形镜自重变形和热变形的主要因素。比较了不同的支撑方案, 发现采用背部三点支撑可以改善周边三点支撑时由重力因素导致的反射面边缘塌陷现象, 在z向重力下面形RMS值由15.38 nm降至4.17 nm, 降低了73%, 且热变形更加均匀, 4 ℃温升时的RMS值由3.68 nm降至3.22 nm, 降低了12.5%, 一阶频率也由1 513 Hz提高至1 982 Hz。这说明该变形镜结构的动、静态刚度及热稳定性均满足空间相机的应用要求。

The aberration correcting ability of deformable mirror is directly affected by the performance of its supporting structure. A structure form of deformable mirror for space camera was described, and different structures of support base were analyzed from the aspect of material properties and manufacturing process, it proves that solid structure made of CFRP is superior to rib-board structure made of TC4, and stiffness ratio of support base material is the main factor of deformation caused by gravity, while the difference of CTE between the materials of support base and reflector affects thermal deformation mostly. Comparing with three-point edge support, the scheme of three-point back support was used to improve the collapse phenomenon caused by gravity, with the RMS value of gravity in z direction decreased by 73%, from 15.38 nm to 4.17 nm, and homogenize the thermal deformation, with the RMS value of 4 ℃ rise decreased by 12.5%, from 3.68 nm to 3.22 nm, and its first order frequency is also improved from 1 513 Hz to 1 982 Hz. This indicates that the dynamic and static stiffness and thermal stability of this deformable mirror satisfies the application requirement for space camera.