高精度离轴非球面镜可控柔体制造关键技术研究

The off-axis aspheric optics is widely used in Earth Observation, Space Observation, and Extreme-Ultraviolet Lithography system, and the figuring accuracy of off-axis aspheric optics is the key factor limiting the system's performance. The off-axis aspheric optics owns complex manufacturing prosperities including off-axis, curvature-variant, high gradient, large sag, and coupling constraints of geometric parameters and so on. The bottle-neck of manufacturing high-precision off-axis aspheric optics is a lack of deterministic figuring method accommodating the curvature of aspheric and high-precision creditable evaluating metrology. The traditional Computer Controlled Optical Surfacing (mechanical CCOS) processes' accuracy reachability is limited due to the misfit of tool and part. The multi-lens fabrication and assemble error in null test makes that the creditable measuring accuracy is almost only 10nm. Therefore, the controllable compliant manufacture method and computer generated holograms (CGH) are regarded as the efficiency ways to fabricate the high-precision off-axis aspheric optics. This proposal mainly focuses on these important science problem including the controllable compliant high-precision figuring theory and optimization process which satisfies the prosperity of off-axis aspheric optics fabrication, the coupling solution can control of geometric parameters, the nonlinear error reconstruction, and creditable evaluation of surface form in CGH measurement, as well as the multi-spatial frequency high-efficiency controllable convergence combined processes and so on. The proposal aims at high-precision and high-efficiency manufacture of the off-axis aspheric optics, and provides technical support for the development of the related area.

离轴非球面在对地观测、对天观测及光刻系统等领域具有广泛应用，其加工精度是制约系统整体性能的关键因素。离轴非球面具有离轴、变曲率、高陡度、大矢高以及多几何量参数耦合约束等复杂制造特征，高精度离轴非球面的制造瓶颈在于缺乏可有效适应非球面曲率变化的确定性加工方法和高精度可信评价的测量手段。传统计算机控制光学表面成形技术（机械式CCOS）中工具同工件的不匹配性导致加工精度可达性有限，补偿器零位测量的多镜头制造组装误差使得面形可信测量精度只能达到10nm左右。因此，实现离轴非球面高精度制造的有效手段是采用可控柔体制造方法和计算机全息图（CGH）测量手段。项目主要研究适应离轴非球面制造特点的可控柔体高精度修形理论和优化工艺，CGH高精度测量中的几何量参数解耦控制、非线性误差重构及可信评价，以及跨频段高效可控收敛的联合工艺路线等关键科学问题，形成离轴非球面的高精度制造能力，并为相关领域发展提供技术支撑。

离轴非球面具有回转对称光学零件无法比拟的优秀性能，是构建现代光学系统的关键零件。高精度离轴非球面的制造及检测是限制其应用的瓶颈难题，本项目结合磁流变可控柔体制造技术和计算机全息图测量方法，深入研究离轴非球面制造及检测中的关键难题。通过突破可控柔体变曲率去除函数建模技术，非线性主动控制面形误差收敛理论，高精度高确定性修形工艺，多参数约束条件下的高精度测量及评价方法，跨频段高效可控收敛的联合工艺匹配及优化，形成离轴非球面的高精度制造能力，实现离轴非球面的高效加工，并在典型工件上得到RMS λ/90的加工结果，为离轴光学系统的发展提供了有效技术支撑。