子孔径拼接中系统误差的修正方法

System error correcting method in sub-aperture stitching

为了提高大口径光学元件子孔径拼接测量的检测精度,提出一种平面绝对测量技术,修正子孔径拼接过程中产生的系统误差。利用改进的三面互检法获得参考平面的面形数据,采用这些测量数据构建基于Zernike多项式的参考面面形误差修正波面,在拼接过程中运用误差修正波面对获得的子孔径测量数据进行实时修正,并与全口径直接测量结果进行对比,结果 PV(peak value,PV,峰谷值)误差从0.072 1λ减少到0.028 6λ。结果表明该方法有效减少了参考平面系统误差对拼接测量精度的影响,提高了大口径光学元件的检测精度。

In order to improve the detection accuracy of the measurement of large aperture optics stitching,a simple and effective absolute measurement was proposed to amend the system error of the sub-aperture stitching measurements.Firstly,an improved three-flat test was used to obtain the surface shape data of the reference plane and the surface error wave-front based on the Zernike polynomial was established which was used to correct the error of the sub-aperture measurement data.Then the directly measured values were compared with the full aperture surface stitching results,and the surface error peak value（DV） was reduced from 0.072 1 λ to 0.028 6 λ.The results show that the method is effective in reducing the system error that caused by the reference plane and can effectively improve the detection accuracy of the large aperture optics stitching.