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.

A case study for cost-effective lens barrel design

“…The difficulty with this is that these tolerances cannot be used as primary parameters 6,7,8,9 . In other words, dimensions that can be independently measured and verified.…”

A Monte Carlo analysis of uncertainty in supporting assembly of large-aperture optical lenses

“…[7][8][9][10] Optical designers are usually concerned about the surface distortion of the lens with deterministic mechanical loads to decide the related dimensional variations but do not pay much attention to its uncertainty distortion caused by assembly variations, for example, the uncertainty supporting loads produced during assembly. 11,12 Cheng et al 13 and Lin and Cheng 14 stated that the traditional optomechanical tolerances scarcely considered the real manufacturing and assembly processes and proposed a novel model of a lens system that integrated the relevant variations determined by manufacturing. Traditional tolerance analyses usually rely upon rigid body assumption for all components.…”

Monte Carlo Model of Optomechanical Tolerance for Lens Assembly

“…Thus, dimensional and geometric tolerances should transfer to the tolerance of tilt ,decenter of the elements and the air space thickness between the optical elements. Studies have been done on this problem [2,3].…”