Extension of an optical coordinate measurement machine with a tactile probe, for combined measurement of optical surfaces and mechanical reference features

Abstract

For aspherical and freeform surfaces not only the surface form error but also the position of the surface relative to external references is important (e.g. fiducials like markers, the outside edge, plane orthogonal surfaces, dowel pin holes). The NMF non-contact measurement machine range for freeform optics by Dutch United Instruments (DUI) can be employed for measurements during the entire production process, measuring ground, polished and coated optical surfaces. This machine has now been extended with a second sensor, either a marker camera or a tactile probe, to measure the position of the optical surface relative to the references features. Tactile probe results are discussed in this paper.