离轴非球面零位补偿检验的三坐标装调技术

Alignment of off-axis aspheric mirror using three-coordinate measuring in null testing

在离轴非球面的零位补偿检验中,为了高精度地检测非球面参数,提出了应用三坐标测量的方法定位零位补偿检验检测光路。建立了应用三坐标测量装调零位补偿检验检测光路的物理模型,计算机求解被检镜的空间方位失调量,实现检测系统的辅助装调。以1个200 mm×100 mm矩形离轴非球面反射镜为例,进行了方法介绍和精度分析。该种方法采用统一坐标系下的绝对测量,唯一定位被检非球面的空间位置,避免位置耦合现象;应用三坐标测量被检非球面的离轴量、补偿器与被检镜之间的光学间隔的精度分别为0.036 mm和0.025 mm,其公差要求分别为±0.25 mm和±0.3 mm。因此,在1 m左右腔长的检测中,可以实现高于被检参数误差1个数量级的高精度检测,为获得正确的离轴非球面加工与检验提供了可靠的技术保障。

In the null testing of off-axis aspheric, in order to test the aspheric parameters with high-accuracy, the alignment method of off-axis aspheric mirror using three-coordinate measuring is proposed. Based on the three-coor- dinate measuring, the optical alignment model is established, and the coordinates of the actual points on the off-axis mirror, which are compared with the data by the theoretical mode to calibrate the misalignment by computer, is obtained by the computer-aided alignment. For a 200 mm × 100 mm rectangle off-axis aspheric mirror, the alignment method is introduced and the precision is analyzed. The merit of using the absolute coordinate measurement is that the place of the tested mirror can be locked uniquely to avoid the coupling phenomena. The tolerance of the lateral displacement and the optical distance between compensator and the tested mirror is ±0.25 mm and ± 0.3 mm, then the measuring precision is 0. 036 mm and 0.025 mm, respectively. Therefore,in the null testing that the optical cavity is less than one meter,the measuring precision is more higher than the tolerance of the measured parameter one order, and the high precision testing, which provides the reliable technique guarantee for the test and manufacture of off-axis aspheric, is realized.