Finite element analysis on mounting configurations for large-aperture optical element

Abstract

Large-aperture optical element is widely used in optical engineering and reasonable mounting results in higher performance. In order to reduce the gravitational sag induced by its own weight, three types of mounting configurations were proposed and simulated by finite element method, and the effects of axial loads and non-uniformity and asymmetry were analyzed in the same time. The results showed that full periphery mounting configuration was the optimal mounting configuration and the optimal axial load was 0.085MPa with the corresponding maximum distortion was 2.32µm, and the effects of non-uniformity and asymmetry on distortion were small.

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

“…With the increasing demand of finer optical resolution, higher imaging quality, and larger field of view, largeaperture lenses are widely used in many applications, such as semiconductor lithography apparatus, solidstate laser facilities, and space telescopes. [1][2][3] These lens systems must be very accurate and must minimize distortion of each lens after assembly. However, large aperture usually results in large gravitational sag of a lens under its own weight, which induces wave front errors into the lens system and further deteriorates its optical performance.…”

“…The optical performance responses, such as surface PV, RMS, and Zernike coefficients, are discussed to explore the influence of the uncertainty supporting loads on optical performance through finite element analysis (FEA). Su et al 2 investigated the distortion of a square optical element with the nonuniformity and asymmetry axis loads in each edge contacted with steel frame, and the resultant surface deformation is varied in the submicron region. In practice, the uncertainty supporting loads, caused by flexure mounts during assembly process, are worse than the above axial loads.…”