应力抛光技术实验装置的研究

基于弹性力学理论的应力抛光技术(SMP)是将非球面加工转化为球面加工的新技术,能够有效地提高非球面加工效率.由应力抛光技术的算法及有限元分析、模拟,针对玻璃材料自身的性质以及在球面镜周边施力或力矩来实现球面到非球面之间变形量的要求,设计、加工和装调一套专门用于应力抛光技术的实验装置,为了实现应力抛光技术中玻璃薄板的球面到抛物面之间的变形,以该装置加工了一块口径为Φ314 mm,F/7的抛物面镜为例,抛光结束的抛物面其峰值(PV)为3.317λ,均方根(rms)为0.489λ,验证了应力抛光技术实验装置的合理性和有效性.     

光学元件检测技术的研究

介绍了光学非球面加工精磨阶段和抛光阶段的检测技术、柱面镜面形的测量方法、超高精度球面面形的测量方法和光学元件参数的高精度测量技术。     

光学加工技术的新发展

对于光学系统要求更好的性能,所以,不断努力寻求更有效的光学加工途径。派肯—爱尔姆在发展非球面和平面加工新技术方面已经得到三种新办法:(1)计算机控制非球面抛光,(2)平面的连续抛光,(3)借助精密表面铣磨机用单颗金刚石工具加工球面及平面。已经加工了口径大于20叶、不平度优于λ/8的光学平板。精密面形铣磨机已成功地用于铝、铜(或铜合金)金属反射镜的加工。     

刀具对中误差对离轴抛物面镜慢刀伺服车削加工的影响

离轴抛物面镜单件高效加工是离轴三反消像散(TMA)结构光学系统的技术难点之一.单点金刚石慢刀伺服车削加工技术可用于离轴非球面加工,加工尺寸范围较大,加工精度较高.此工艺制造的离轴抛物面面型精度可达到亚微米级,粗糙度达到纳米级.因此,可直接用于红外光学应用,若经后续抛光则可用于空间望远镜等更高精度需求的场合.介绍了慢刀伺服车削加工离轴抛物面镜的在轴加工方法,理论推导了刀具对中误差所带来的面形误差的极值分布规律.仿真研究进一步揭示了工件中心区域面形误差的详细分布.实验数据与理论结果和仿真计算结果均吻合.     

计算机数控应力盘面形研究

简要讨论了计算机控制应力盘抛光大口径高陡度非球面的基本原理,用Zernike多项式拟合的数学方法研究应力盘工作过程中的面形动态变化,对这一方法所能达到的精度进行了分析,给出了计算结果.     

超轻超薄反射镜制造过程中的变形控制研究

针对超轻超薄反射镜(超薄镜)径厚比大,自身刚度小、单独加工难度大的问题,采用基底支撑方式对超薄镜进行加工.我们研究了在加工过程中粘接,温度、应力等因素所导致的超薄镜变形的控制手段并对变形控制效果提出了评判方法.通过195 mm口径超薄铣工艺实验对控制变形的工艺进行改进,用改进后的加工工艺进行了340 mm口径的超薄镜制造,得到了比较理想的面形,下盘后PV值5.74λ,RMS值1.02λ(λ=632.8 nm).这表明在超薄镜制造过程中变形控制的技术方案可行,工艺改进方向正确.同时,实验结果表明,超薄镜制造过程中的变形最终表现为镜面出现非重力因素引起的像散.     

光学元件聚氨酯抛光特性研究

本文研究了应用于平面光学元件的快速抛光技术,从材料去除率、元件面形和表面粗糙度出发,对快速抛光技术应用于平面大口径元件的加工效果进行了探讨。研究了在快速抛光技术中压力和主轴转速对材料去除率的影响,验证了Preston公式在快速抛光中的适用性,快速抛光技术的去除效率可达10μm/h;其次,研究了聚氨酯抛光元件面形的精度,对于330mm×330mm元件可达～1.0λ（λ=632.8nm）;最后,对快速抛光系统中抛光粉颗粒大小及形态随使用时间的变化进行了观测,并测量了使用300目和500目抛光粉时快速抛光元件表面粗糙度以及其随抛光粉使用时间的变化。     

我国600m直径碳化硅主镜光学加工获突破

上海技物所公共技术研究室经过一年艰苦攻关,在型号任务600mm直径碳化硅主镜光学加工取得突破,根据光学精度特性分析和检测,其面形精度、表面粗糙度、焦距等关键参数均达到或优于设计要求,特别是面形精度实测为1／8λ（pv）、0．014λ（rms）,已达到国内先进水平。     

计算机数控应用盘面形研究

简要讨论了计算机控制应力盘抛光大口径高陡度非球面的基本原理,用Ｚｅｒｎｉｋｅ多项式拟合的数学方法研究应力盘工作过程中的面形动态变化,对这一方法所能达到的精度进行了分析,给出了计算结果。     

磁流变抛光光学曲面的两级插补算法

根据磁流变抛光的加工特点,本文提出一种加工光学曲面的粗、精两级插补算法。粗插补算法控制工件的面形,精插补算法采用PVT模式,可实现对磁流变抛光光学曲面复杂过程的控制。仿真结果表明,采用该插补算法加工R41.3mm、口径20mm的球面工件,插补误差小于0.45nm,磁流变抛光该尺寸的K9光学玻璃,获得PV57.911nm的面形精度。     

成像光学工程面临的光学问题

文章简单论述了现代成像光学主要领域的情况,指出非球面反射系统是发展的必然趋势。讨论了加工与检验方面的基本情况及应着重深入研究的问题。对镜坯材料也提了一点看法。     

Fabrication and alignment issues for segmented mirror telescopes

There is a great demand for new telescopes that use larger primary mirrors to collect more light. Because of the difficulty in the fabrication of mirrors larger than 8 m as a single piece, they must be made with numerous smaller segments. The segments must fit together to create the effect of a single mirror, which presents unique challenges for fabrication and testing that are absent for monolithic optics. This is especially true for the case of a highly aspheric mirror required to make a short two-mirror telescope. We develop the relationship between optical performance of the telescope and errors in the manufacture and operation of the individual segments.     

环形子孔径检测技术中测量数据的准确提取方法

环形子孔径拼接测试技术是一种无需辅助元件就能检测旋转对称大口径非球面镜的有效手段。根据该技术的检测原理及基于Zemike多项式的“拼接”算法，提出了一种相应的环形子孔径数据提取方法。该方法基于商用相移干涉仪的CCD成像系统和其数据处理软件提供的Mask编辑功能，利用被测镜面上方的三个可移动的基准标记进行绝对定位，给出了具体的实施方案。对一口径700mm、F2的抛物面主镜进行实验，研究结果表明，该数据提取方法操作简单可行，适合于加工车间的实施，取得了符合“拼接”算法需求的子孔径测试数据和对应环带的内外半径值。     

Development of bridge tooling for fabricating mold inserts of aspheric optical lens

A bridge tooling is developed for fabricating the temporary mold inserts of aspheric lens using silicone rubber materials. Prototype material of the aspheric lens is not recommended as quartz due to low successful rate in the fabrication process. This technology provides a fast, low cost, and high successful rate for fabricating the epoxy‐based composites mold inserts of plastic aspheric optical lens.     

Measurement based on fringe reflection for testing aspheric optical axis precisely and flexibly

A method based on fringe reflection is proposed to measure the optical axis of an aspheric mirror precisely and flexibly. In the measurement, a screen displaying a fringe pattern is moved along its normal direction, and a camera is located beside and observes the fringe pattern reflected via a tested surface. This method can test the optical axis of an aspheric mirror quantitatively before measuring the absolute height of the tested surface. And it can be combined with some presented methods that need to fit the aspheric mirror according to the optical axis to measure the surface. To validate the ability of this method, it is combined with one of the presented methods to measure absolute height of an aspheric mirror precisely and flexibly. Computer simulations and preliminary experiment validate the feasibility of this method.     

高效非成像聚光光学系统设计与性能分析

针对菲涅尔透镜存在实际光学效率偏低的问题,本文设计了一种由非球面透镜和棒锥镜组成的高效非成像聚光光学系统。在光学设计软件Zemax的序列模式下对非球面透镜进行了优化设计,通过最大程度地减小球差,像面光斑的几何半径从42 mm降到了1.7 mm。基于此,在Zemax的非序列模式下,完成了非球面透镜和棒锥镜的建模和优化,通过蒙特卡罗光线追迹分析实现了光学效率为87%、接收角为0.9°的非成像聚光光学系统。最后,基于非球面透镜阵列和棒锥镜样品,实现了高倍聚光型光伏模组的封装与测试。测试结果表明,该模组的光电转换效率达30.03%,与菲涅尔透镜构成的高倍聚光型光伏模组相比有显著提升。     

二元光学元件横向加工误差对衍射效率的影响

横向加工误差包括对准误差和线宽误差,加工误差对衍射效率的影响是二元光学元件研究的重要问题.本文基于标量衍射理论,提出了一种与MATLAB相结合的分层计算方法,重点分析了4阶和8阶二元光学元件横向加工误差和衍射效率的关系.结果表明,控制8阶二元光学元件对准误差,可抑制衍射效率的迅速下降,适当调整线宽能够减小对准误差造成的...     

Efficient testing of segmented aspherical mirrors by use of reference plate and computer-generated holograms. I. Theory and system optimization

Telescopes with large aspherical primary mirrors collect more light and are therefore sought after by astronomers. Instead of large mirrors as a single piece, they can be made by use of numerous smaller segments. Because the segments must fit together to create the effect of a single mirror, segmented optics present unique challenges to fabrication and testing that are absent for monolithic optics. We have developed a new method for measuring large quantities of segments accurately, quickly, and economically using an interferometric test plate and computer-generated hologram (CGH). In this test, the aspheric mirror segments are interferometrically measured by use of a test plate with a best-fit spherical surface. The aspherical departure is accommodated with a small CGH that is imaged onto the test plates. The radius of curvature is tightly controlled by maintaining the gap between the test plate and the segment. We present a summary of the test and give the basic design tradeoffs for using a single system to measure all of the segments of a large aspheric mirror.     

Self-pumped phase conjugation in microspheres

When a microscopic sphere is illuminated by a laser beam, interference fringes inside the sphere lead through the Kerr effect to a holographic grating. This grating is capable of phase conjugation, which is particularly strong when optical resonance takes place. According to numerical simulation, based on the Green function method, phase-conjugation reflectivity R = 0.5 can be achieved in a single silica sphere of approximately 9-microm diameter with realistic laser power. Such spheres can be aligned together to become a phase-conjugation mirror of large area and high reflectivity.