针对非球面反射镜在抛光初期干涉仪不能全口径检测面形误差的问题,提出一种三坐标测 量机(CMM)和数字干涉仪组合测量以实现全口径波前复原的方法。将CMM与干涉仪测量数据组合, 即面形误差以干涉测量为主,干涉检测不能复原的局部波前采用CMM测量数据进行精细重构,从 而获得可用于数字化加工的全口径面形误差,并最终达到非球面镜全口径干涉检测。采用该方 法对Φ为540 mm的离轴非球面反射镜在精磨后期进行数据组合补偿,成功实现了反射镜从精磨阶段 到抛光阶段的全口径波前检测,从而证明了该方法对实现非球面镜全口径检测有效可行。

In order to realize wavefront reconstruction over full aperture of aspheric surface at the beginning of polishing, a novel method combing coordinate measuring machine (CMM) and digital interferometer was proposed. The main part of surface is able to be measured by interferometer. The rest part, wavefront of which cannot be recovered by interferometer, can be measured by CMM. By combing the data from CMM and interferometer, the error of surface can be reconstructed and the wavefront over full aperture can be obtained ultimately. In the testing, wavefront of an off-axis aspheric surface with 540 mm diameter was successfully reconstructed over full aperture during the process from grinding to polishing. The availability of the method for wavefront reconstruction of aspheric surface was proved by the results.