In-situ shape measurement technology during large aperture optical planar continuous polishing process

Continuous polishing technology is an important means to realize batch processing of large aperture and high precision planar optical components. However, traditional continuous polishing process largely depends on the operator's experience, with poor controllability of component surface figure and unstable processing efficiency. In order to solve this problem, the in-situ shape measurement technologies including measurement of pitch lap surface figure and workpiece surface figure have been proposed in this paper. The real-time states of the pitch lap flatness and the workpiece surface figure in polishing process are obtained by in-situ measurement technologies, which provide the quantitative informations for adjusting process parameters. In the experiment, a large aperture mirror (material as K9; size as 800mmx400mmx100mm) was polished. The results show that the surface figure of the component was improved from lambda/2 (1 lambda= 632.8nm) to lambda/6 by using the in-situ measurement technologies during the continous polishing process.