特大非球面度离轴非球面补偿器结构设计与装调

Structure design and assembling of compensator for off-axis aspheric surface with large asphericity

针对快焦比特大非球面度离轴非球面反射镜,设计了3片式Offner补偿器。为应对3片式补偿器对中心偏差及镜间隔严格的公差要求,设计了相应的补偿器镜筒结构。该结构使透镜中心倾斜及平移调整相分离,实现补偿器的高精度装调。根据中心偏差测量仪的测量结果,2片补偿镜之间倾斜误差4.4″,平移误差3.5μm,镜间隔误差3.8μm;补偿镜组与场镜之间倾斜误差5.3″,平移误差4.2μm,镜间隔误差7.2μm,满足检测使用要求。利用该补偿器及4D动态干涉仪对精抛光阶段的离轴非球面进行检测,面形结果PVq值达到0.135λ,RMS值达到0.019 5λ,优于设计要求。

Three-lens Offner compensator was designed for off-axis aspheric surface with fast rati- o and large asphericity. Because tolerance requirement of centering errors and air gap distances is very severe, corresponding barrel structure of compensator is designed. The structure sepa- rates line-centering error adjustment and angle-centering error adjustment, which can achieve high accuracy adjustment of the compensator. According to measuring results of center deviation measuring apparatus, finally angle-centering error between compensating lenses is 4.4＂, line- centering error is 3.5 μm, and air gap distance error is 3.8 μm. Angle-centering error between compensating lenses series and field lens is 5.3＂,line-centering error is 4.2 μm, and air gap dis- tance error is 7.2μm, which meet the demand of testing. Off-axis aspherical surface is tested by 4D interferometer and the compensator,PVq value is 0. 135X and RMS value is 0. 019 5X, better than designing requirements.