非球面非零位检测中的回程误差分析与校正

Analysis and Correction of Retrace Error for Nonnull Aspheric Testing

光学测试中常用非零位法来对非球面进行初步检测。由于非零位法偏离了零位条件,导致检测得到的被测非球面而形与其真实面形存在一定程度的偏差(称之为回程误差)。分析了非球面非零位检测系统中的回程误差问题,得出了回程误差与被测非球面口径、相对口径以及非球面本身面形误差均紧密相关的结论。针对回程误差的表现形式,提出了有效校正回程误差的方法。计算机仿真及检测实验结果均表明,该方法可以较好地解决非球面非零位榆测中的回程误差问题。针对非球面非零位检测中回程误差问题所做的分析以及提出的相应校正方法,有利于非球面非零位法检测精度的提高和系统的广泛应用。

Nonnull test is often adopted in optical metrology for aspheric testing. But due to its violation of null condition, the obtained surface figure would be different from that of the real, which is called retrace error accordingly. Retrace error of nonnull aspheric testing is analyzed in detail with conclusions that retrace error has much to do with the aperture, relative aperture and surface shape error of the apsheric under test, Correcting methods are proposed according to the manner of the retrace errors. Both of computer simulation and experimental results show that the proposed methods can correct the retrace error effectively. The analysis and proposed correction methods bring much to the application of nonnull aspheric testing.