A study on the optomechanical tolerance model for lens assembly

Abstract

Optomechanics is defined as the science or engineering of maintaining the proper shapes and positions of the functional elements in an optical system. At the optomechanical interface, manufacturing tolerances affect the shape and position of the surface in a lens system. Even very small variations will cause extra aberrations which degrade the optical performance of a lens system. The traditional approach to the optomechanical tolerance design is a top-down process. The optical designers typically designate the critical to quality parameters, such as tolerances of tilts, decenters, and locations of optical elements. A significant drawback of this top-down process is that the tolerances determined by optical designers do not take the real manufacturing and assembly process into consideration. As a result, some tolerances are too tight for the manufacturing, and the yield rate of the production is difficult to improve. The objective of this study is to develop a surface based optomechanical tolerance model that calculates the variation of the critical to quality parameters for a lens system. The distribution of these parameters can be treated as inputs to the optical design. Therefore, the optical performance will be predictable than the top-down approach, and the manufacturability of the optical system can be improved.