基于SiC材料的空间相机非球面反射镜结构设计

针对空间相机中优质轻型光学反射镜对材料提出的要求,详细讨论了设计基于SiC材料空间反射镜的一系列问题,包括径厚比的选择、支撑点数量、轻量化结构形式、材料特性匹配等,提出了一种背部半封闭、三角形孔的轻量化形式,并设计制造了 Φ600 mm轻量化SiC反射镜实验件。抛光后反射镜面形精度优于λ/20 rms。为验证重力变形的影响,将反射镜分别旋转了90°和180°,用Zygo干涉仪检验,3个方向检测结果误差均小于λ/100 rms。在此基础上设计完成了某空间相机中的SiC非球面主镜、次镜、第三镜,结果表明基于SiC材料的反射镜在重力变形、谐振频率、热变形等方面均能满足使用要求,而且与玻璃材料相比,在很大程度上降低了重量。     

Scanning measurement of aspheres

The measurement of aspheres today is often done using computer generated holograms with interferometry. We show that this method holds some significant systematic errors caused by imperfect adjustment of the optical components. This gives rise to the question if a measurement is possible without utilization of computer generated holograms. Therefore we propose a new elliptical setup using a laser interferometer and a set of scanning mirrors. Our work shows that this setup is capable of form measurement for individual aspheres but still poses some adjustment challenges.     

The NANOMEFOS non-contact measurement machine for freeform optics

Aspherical and freeform optics are applied to reduce geometrical aberrations as well as to reduce the required number of components, the size and the weight of the system. To measure these optical components with nanometre level uncertainty is a challenge. The NANOMEFOS machine was developed to provide suitable metrology (high accuracy, universal, non-contact, large measurement volume and short measurement time) for use during manufacturing of these surfaces. This paper describes the design, realization and testing of this machine. In particular it describes the design and testing of the air-bearing motion system with parallel stage configuration, and the separate metrology system with Silicon Carbide metrology frame and an interferometry system for direct displacement measurement of the optical probe. Preliminary validation measurements demonstrate the nanometer level repeatability for freeform surface measurement.     

轴对称非球面平行磨削Y轴向对刀误差补偿

在光学系统中应用非球面光学元件能够提高光学系统设计灵活性,改善光学系统成像质量,缩小光学系统尺寸,在整体上减轻系统质量。本文通过系统分析轴对称非球面元件精密磨削工艺过程中的轴向对刀误差等加工误差因素,建立轴向对刀误差校正方法,并将其运用到轴对称非球面精密磨削与抛光加工过程中。由实验可知：通过误差补偿,加工时间节省60%以上,Φ80mm口径非球面抛光后的面形精度PV值为0.62μm（0.982λ）,RMS值达到0.093μm（0.147λ）,满足非球面面形精度要求。实验结果验证了理论分析与误差补偿方法的正确性,实现了轴对称非球面光学元件的快速精密加工。     

精研磨阶段非球面面形接触式测量误差补偿技术

在对高精度非球面光学元件进行磁流变抛光制造过程中,为了提高达到最终要求的15～30 nm(方均根值)光学级面形精度的加工效率,必须经过非球面面形快速修正的精研磨过程。针对精研磨阶段的面形误差数字化技术进行了深入分析,建立了分离影响误差收敛精度的线性误差矩阵,并借助于一块具有中心遮拦孔的同轴抛物面反射镜进行验证,结果表明所建立的倾斜误差分离矩阵对于指导非球面研磨阶段的面形检测具有明确的效果,能够提供该阶段待检测工件面形的准确信息,保证了研磨阶段检测与加工的密切衔接,缩短了进入光学抛光阶段的周期。     

磁流变抛光技术的研究现状及其发展

磁流变液是近年来得到广泛重视的一种新型的智能材料,应用磁流变抛光技术对光学材料进行确定性加工得到了越来越多的重视.本文对国内外磁流变抛光技术的研究概况进行了综述.介绍了磁流变抛光技术在光学加工中的应用,分析了其中应重点解决的问题,并对磁流变抛光技术的发展前景进行了展望.