30m望远镜三镜镜面面形误差的斜率均方根评价

发布时间：2018-11-14 08:57

【摘要】：由于传统的均方根方法在评价大口径反射镜时难以精确表达光学表面的中空间频率误差,本文提出了基于斜率均方根(SlopeRms)的误差评价方法来评价光学表面面形。该方法先以Zernike多项式拟合光学表面面形,在此基础上求解不同空间间隔上的斜率均方根。这种评价方法可以很好地区分小尺寸磨削工具造成的误差和大口径反射镜在多点支撑下造成的面形误差。文中建立了SlopeRms的数学模型,推导了SlopeRms的计算方法,并以此方法为基础对30m望远镜(TMT)三镜面形进行了评价。结果显示,采用斜率均方根的评价方法得到的光学表面面形值达到0.9μrad,优于传统的RMS评价方法(RMS=115nm),满足设计要求。结果显示,基于斜率均方根的误差评价方法能更加全面和客观地评价大口径反射镜面形,具有实际意义。
[Abstract]:Because the traditional RMS method is difficult to accurately express the middle spatial frequency error of optical surface in the evaluation of large aperture reflector, this paper presents an error evaluation method based on slope root mean square (SlopeRms) to evaluate the surface shape of optical surface. Firstly, the Zernike polynomial is used to fit the surface shape of the optical surface, and on this basis, the root mean square (RMS) of slope at different spatial intervals is solved. This method can well distinguish the errors caused by small grinding tools from those caused by large aperture mirrors under multi-point support. In this paper, the mathematical model of SlopeRms is established, the calculation method of SlopeRms is deduced, and the (TMT) three-mirror shape of 30m telescope is evaluated on the basis of this method. The results show that the optical surface shape obtained by the slope RMS method is better than the traditional RMS evaluation method (RMS=115nm), which meets the design requirements. The results show that the error evaluation method based on the slope root mean square can evaluate the large aperture reflection mirror more comprehensively and objectively, which is of practical significance.
【作者单位】：中国科学院
【基金】：中科院三期创新工程资助项目
【分类号】：TH743

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