基于Ronchi光栅检测非球面镜系统中的杂光现象分析

Analysis of Stray Light in Aspheric Mirror System Detection Based on Ronchi Grating

为指导某600 mm口径的双曲面反射镜的加工,设计了Ronchi光栅检测系统。针对系统检测过程中存在的杂光现象,分析产生该现象的原因,并提出相应的解决方案。结果表明,在光线两次经过光栅的光路结构中,分光棱镜的剩余反射率大于5%时,像面处暗条纹的照度增大27倍,条纹明暗对比度下降,难以分辨;随着光栅剩余反射增加,条纹中心产生亮斑现象,条纹无法分辨。条纹面正对分光镜的亮斑区域的背景照度增加40多倍,玻璃面正对分光镜的亮斑区域的背景照度增加80多倍。通过优化系统结构,对分光镜与光栅进行替换与表面处理,有效解决了杂光问题,提高了像面条纹对比度。

In order to guide the machining of a 600 mm hyperboloid mirror,the detection system of Ronchi grating is designed.In view of the stray light phenomenon in the process of system detection,the causes of the phenomenon are analyzed,and the corresponding solutions are put forward.The analysis results show that when the residual reflection of the splitting prism is greater than 5%,the illumination of the dark fringe on the image plane increases by 27 times,and the contrast of the fringe decreases,making it difficult to distinguish.With the increase of the residual reflection of the grating,bright spots appear in the center of the fringe,and the fringe cannot be distinguished.The background illumination of the bright spot area of the spectroscope is increased by more than 40 times by the striped surface,and the background illumination of the bright spot area of the glass surface is increased by more than 80 times.By optimizing the system structure,the spectroscope and grating are replaced and treated.The stray light phenomenon is effectively solved and the contrast of the image plane fringe is improved.