Optical wavelength selective devices having rigid support structure

摘要

Rigid supporting structures for the components of high precision optical instruments, such as interferometers or monochromators, have hitherto been based on massive castings. Such castings suffer from residual non-recoverable changes of shape during temperature cycling, due to the differential temperatures set up in the castings. The invention provides a rigid structure assembled from a number of flat sheet structural elements. Each sheet element is substantially rigid in its own plane and is attached to one or more other sheets at points of contact which are such that the edge of one sheet bears against the surface of another sheet with the planes of the two sheets being perpendicular in the region of the points of contact. An open ended rectangular box structure may be assembled from two sheets, each with a single right angled fold. Each point of contact and attachment may be formed as a foot standing proud from the remainder of the sheet edge.