A case study for cost-effective lens barrel design

Abstract

A case study is presented to illustrate some of the performance and cost driving tradeoffs involved in the design and tolerancing of optics and optomechanics, where simple lens barrels are concerned. A double Gauss lens was designed, along with two variations of lens barrel designs for mounting the lenses. The two lens barrel designs are compared, and one is selected for further analysis. Tolerance selection guidelines are given and discussed for the optics, as well as the optomechanics. It is shown how the optomechanical tolerances (axial spacing, element decenter, and element tilt) are derived from their primary parameters for the selected lens barrel design. Finally, Monte Carlo analysis is used, along with the provided tolerancing guidelines, to determine reasonable tolerances in order to satisfy the optical performance and yield requirements.

Monte Carlo Model of Optomechanical Tolerance for Lens Assembly

“…Moreover, the Monte Carlo tolerance analysis function of the optical design software need the input of the distribution type of the optical tolerances, which may be hardly decided before the mechanical structure is determined, so that it is hard for optical designers to design the tolerances. The tolerance model may be different between different structures [5]. In order to improve the tolerance analysis function of the software, technology of the communication between the analysis model and optical design software need further research.…”

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.…”