球面干涉检测中改进的调整误差校正方法

根据球面干涉检测中待测球面调整误差的高阶近似模型,提出新的基于泽尼克多项式拟合的球面调整误差校正方法.该方法根据测得原始面形数据的泽尼克多项式系数以及待测面数值孔径,得到调整误差所引入的低阶和高阶像差量,实现高精度球面调整误差校正.通过Zygo干涉仪及大数值孔径待测球面对提出的校正方法进行实验验证,校正精度达到了均方根值近0.001λ、峰谷值0.011λ.实验结果表明,该方法可以实现很高的球面调整误差校正,无需了解实际调整误差量,便于自动化处理,可以降低检测装置中对待测面调节机构精度的要求.

Improved method for misalignment calibration in interferometric testing of spherical surface

According to the high-order approximation model of misalignment in interferometric testing of spherical surfaces, an improved method based on Zernike polynomials fitting was proposed to calibrate the misalignment aberrations of test spherical surface. With the numerical aperture of test surface and Zernike polynomial coefficients of measured raw surface data, both the low-order and high-order aberrations introduced by misalignment can be acquired and removed from the measured raw surface data. Then high precision calibration of spherical surface misalignment can be realized. Experimental validation was conducted with Zygo interferometer, and a high-numerical-aperture test spherical surface was tested to demonstrate the feasibility of the method. The high calibration precision with root-mean-square and peak-valley values 0.001λ and 0.011λ, respectively, was gained. Ultra-high misalignment calibration precision can be realized according to experimental results. The method requires no foreknowledge about the specific adjusting error and is convenient for automatic processing, and lowers the accuracy requirement on the adjusting mechanism for the spherical surface under test in testing system.