子孔径拼接技术在大口径高陡度非球面检测中的应用

Application of subaperture stitching technology to test of large and steep aspherical surface

为了能够精确地完成对大口径高陡度非球面在细磨和抛光过程中的测量,提出了一种将子孔径拼接技术和补偿技术相结合的检测方法。介绍了该方法的基本原理,建立了合理的数学模型,编制了拼接计算软件。利用该方法对一外形尺寸为400 mm×300 mm的高次离轴非球面进行了测试,通过最小二乘法拟合消去各子孔径相对基准子孔径的调整误差以及整个系统的装调定位误差,得到了准确的全孔径面形分布。对实验精度和误差来源进行了分析,并将拼接面形与全孔径测量面形相对比,二者是一致的。

In order to test large aperture and high steep aspheric surfaces accurately during the grinding and polishing process, a new method combining the subaperture stitching and null compensation was proposed. The principle of the technique was introduced, and a reasonable splicing mathematical model was established. A steep, high order and off-axis aspheric mirror with a aperture of 400 mm×300 mm was tested with the method. The translation and misalignment errors were eliminated by the least-squares fitting and the phase data of the full aperture were obtained, and the surface map after stitching was consistent to the integrated surface map derived by null corrector. Moreover, the errors and accuracy of the experiment were analyzed.