Precision Grinding and Polishing of Optical Micro-structured Surface

In fields like imaging and illumination, different types of optical struc-tured surface have been used in a wide variety of applications. However, defects such as tool marks, burs and debris are normally left on the structured surface during the machining process. How to remove aforesaid defects, and furtherly improve the surface quality with a higher efficient, so as to reach better functional performance is still a challenging problem. This chapter presents an advanced method, maskless fluid jet polishing (MFJP), to solve this problem. In MFJP, without using a mask, material can be removed in a tiny scale by low pressure micro abrasive water jet slurry impinged on the structured surface. On the basis of the analysis of surface rough-ness, form maintainability, and surface smoothness, experimental investigations on the polishing of sinusoidal structured surface and V-groove structured surface were performed to achieve the technical feasibility of MFJP on structured surface. In order to prove the fluid flow movement and material removal characteristics and to achieve a simulation of the MFJP process on V-groove surface, a computational fluid dynamics (CFD) model was also developed. Additionally, the influence of the key polishing parameters was also researched and discussed. The results indicate that MFJP can observably improve the surface quality of optical structured surface, while achieving high form maintainability under defined conditions. As a potentially competitive method for the precision polishing on optical structured surfaces, MFJP can also hold promise for polishing other surfaces with small or micro-meter sized cavities or channels, such as microfluidic chips, etc.