近柱面中频面形检测中曲面拟合法精度问题研究

Investigation of the precision of curved surface fitting in the measurement of near-cylindrical surfaces′ mid-wavelength deformations

研究了曲面拟合法对特定抛物和双曲近柱面检测中波前像差的处理过程,结果表明,对振幅为0.1λ的中频正弦型面形,由曲面拟合法得到的结果与该正弦型面形之差的RMS值分别可以达到0.015λ(8.25nm)和0.013λ(7.15nm).通过分析拟合阶数对精度的影响,确认存在一个特殊的阶数no、它使曲面拟合法的精度达到最高;讨论了估计no值的方法,得到了和no真实值完全符合的估计值,表明这些方法是行之有效的.

The application of curved surface fitting for the disposal of the wavefront aberrations got in the measurement of certain paraboloid and hyperboloid is studied. It is found that, for mid-wavelength deformations with an amplitude of 0.1 lambda, results can be obtained with RMS error smaller than 0.015 lambda and 0.013 lambda separately. The existence of a special fitting order which leads to the smallest RMS error is affirmed. To find out the special fitting order, we work out two methods which help us get the order's value successfully.