应用细小离子束加工小型精密光学零件

Study on Machining Small Precision Optical Component Using Thin Ion Beam

随着现代光学技术的发展,全频段误差控制已成为高精度光学零件制造的一个基本要求。基于小磨头抛光原理的先进修形技术虽然能有效修正低频面形误差,但对于中高频段的面形误差难以修正。中高频误差成为了现代光学加工普遍关注的难点。理论研究表明,减小小磨头尺寸可以提高工艺对中高频误差的修正能力,进一步提高光学加工精度。本文针对中高频面形误差的控制问题,开展细小离子束修形工艺研究,研究了获取小束径离子束的引束机理和引束结构,初步实现了稳定的细小离子束,针对某小型精密光学元件的具体加工问题,仿真研究了不同束径的加工效率和加工残差,并选择最优束径对元件进行了加工试验,使元件的精度从初始的0.111λrms减小到了0.015λrms(λ=632.8nm)。

With the development of modem optical technology, there has been a basic requirernent to control the surface error in all spatial frequency ranges for precision optics. The low spatial frequency range error of the surface can be easily and effectively eliminated by CCOS methods, but for the surface error in the middle and high spatial frequency ranges, there are few effective methods to correct them. Hence it has becomes a tmiversal concern in modem optical manufacturing because of its serious influence on some modem precision optical systems. As is proved previously, the correcting ability of middle and high frequency error can be improved by reducing the size of the polishing lap. Based on this theroy, the small ion beam figuring methede has been intruduced to solve the problem of mid and high frequency error correcting. Firstly, we studied how to gain small and steady ion beams by two methods. Then we designed a series of actual figuring experiment and computer simulation to test the effecfivness of those mothods on small scale optic surfaces. The desired results have been gained to reduce the surface error from 0.111λnms to 0.015λ nms （2 = 632.8nm）.