Free-form surface profilometry based on subtracting CMM date from enveloping surface

Abstract

Freeform optical components (FOCs) can effectively simplify optical system configuration and improve optical preforms, they can be applied on imaging system, illumination system and phase compensation system. Scattered sagittal points reported by coordinate measuring machine (CMM) often exist uncertainty and makes contour error inaccurate. A new model which subtracts CMM date from enveloping surface calculated by theoretical equation includes tilt, rotation and shift. Experiments result shows this method introduced by this article could efficiently analysis scattered CMM data and PV (Peak-to-valley) less than 2 μm which matched accuracy of CMM (1.8+ L/300 μm) and accuracy of fabrication error of SPDT.