应用离子束进行光学镜面确定性修形的实现

为了克服传统光学镜面抛光方法的缺点,提出了应用离子束进行光学镜面修形的方法.介绍了离子束修形技术的原理和方法,并对离子束修形中涉及的关键技术进行了讨论.在自研的离子束修形设备上对一块直径φ98 mm的微晶玻璃平面样件进行了离子束修形试验,经过两次的迭代修形使其面形精度均方根误差由初始的0.136λ提高到0.010λ(λ=632.8nm),平均每次迭代的面形收敛率达到3.7.实验结果表明,应用离子束进行光学镜面修形无边缘效应、面形收敛快、加工精度高;由于离子束修形技术去除材料过程自身的特点,使数控离子束修形技术对非球面的加工和对平面的加工难度相当.

Deterministic Figuring in Optical Machining by Ion Beam

Ion beam figuring (IBF) is introduced to overcome the disadvantages of conventional polishing processes in optical machining. The principle and method of IBF are introduced, and the key techniques required to implement an IBF process are also discussed. To demonstrate an IBF process, a 98 mm planar ceramic glass was processed on an IBF system. Its surface figure accuracy root-mean-square (RMS) is improved from initial 0.136λ to final 0.010λ(λ=632.8 nm) through two IBF processes, and the mean iterative convergence ratio is 3.7. The result shows that the IBF is a deterministic process, which results in a high surface figure accuracy without edge effect and a corresponding high convergence ratio of surface figure. Due to the unique characteristic of the sputtering process in IBF, machining an aspheric surface is no more difficult than machining a planar surface.