超薄光学元件精密加工关键技术

Key technology of ultra-thin optical element precision manufacture

针对超薄光学元件在加工过程中因重力和磨头产生应力形变的特点,提出了一种高效、先进的超薄光学元件综合加工方法。该方法综合运用了精密铣磨、精密抛光、离子束修形等先进技术进行面形控制。在铣磨阶段采用受力分析和误差补偿的方法降低了元件变形引入的面形误差;在抛光阶段通过气囊抛光和沥青抛光的迭代实现了面形快速收敛;在离子束加工阶段充分利用其非接触、无应力的加工特点实现了高精度面形修正。实验选择径厚比为34(边长152 mm,厚度6.35 mm)的方形融石英材料进行加工实验。结果表明:在铣磨、抛光、修形阶段的各项指标都达到了精密光学元件的加工水平,最终的面形精度为PV=25 nm,RMS=1.5 nm。该加工方法可以广泛应用于超薄光学元件的高精度加工。

Because of the difficulty to fabricate the ultra-thin optical element,this paper presents an efficient, advanced ultra-thin optical components integrated processing method to resolve the deformation problem.This method integrates precision grinding,precision polishing,ion beam figuring and other advanced technologies to acquire high-precision surface accuracy.In the grinding stage,the experiment uses force analysis and error compensate to reduce surface error caused by deformation.In the polishing stage,the experiment utilizes mul-tiple iterative process to achieve surface error fast weaken .In the ion beam figuring stage,the experiment takes advantage of unstressed and non-contact of this processing method to achieve high-precision surface ma-chining.Coring square material is chosen for the processing experiments.The result shows that the surface er-ror has reached the level of ultra-precision optical components,and the final surface accuracy is PV =25 nm, RMS =1 .5 nm.This method can be widely used for high-precision machining of ultra-thin optical compo-nents.