Rigid body movements of optical elements due to opto-mechanical factors

Abstract

Techniques and formulas will be presented that demonstrate an effective means of characterizing the rigid body motions of optical elements from their nominal positions as caused by manufacturing tolerances and thermal effects. These techniques allow accurate prediction of the final position of a mechanically held lens element to be determined relative to mechanical datums. Even a single lens element with entirely nominal dimensions often needs to be positioned relative to a mechanical reference; the effects of any inherent inaccuracy of the mounting process can be over-looked and/or oversimplified. Tolerances on lens seats, element radii, bore diameters as well as thermal effects need to be accounted for in a design in order to accurately predict the final optical performance of a system in an "as built" condition. The differences in accounting for the mounting tolerances of edge mounted, cell mounted, and surface-centered elements are discussed. The work presented will aid in linking the tools available to the optical engineer in the form of optical design software, with the data available to the mechanical engineer in the form of manufacturing and fabrication tolerances.

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.…”

Opto-thermo-mechanical phenomena in satellite free-space optical communications: survey and challenges

“…The satellite microvibrations and the thermal loads can also induce rigid body motions of the optical components inside the satellite. 74 These rigid body motions will, in turn, induce pointing jitter, defocus, and other high-order optical aberrations [see Fig. 7(a)].…”

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.…”