Support Structures for High‐Resolution Optical Systems

Abstract

High‐resolution optical systems require support structures that isolate the optical elements from mechanical and thermal loadings. Because the requirements for precise fabrication of the support structure are generally much less rigorous than they are for the optical element surface, the optical quality of the system can be degraded if the optical element is rigidly attached to the support structure. For small optics that can be treated as rigid elements, kinematic (statically determinate, point support) mountings may be used. For larger optics, however, finite contact surfaces (pads) are required to reduce contact stresses so that a semikinematic support results. If the contact surfaces are not coplanar, the optical element can be distorted. To circumvent this latter problem, support pads with self‐aligning designs may be used. These designs may either be mechanisms or flexures. Flexures are used more generally because they are free of both friction and hysteresis. For large optics, the optical elements require numerous supports so that the support system is highly statically indeterminant. These systems require analysis using the finite element method to meet optical deflection design criteria.