Integrated wavefront sensor and profilometer

Abstract

An instrument for measuring aspheric optical surfaces includes both an optical wavefront sensor and a single-point optical profilometer. The optical wavefront sensor measures surface height variations throughout one or more areas of an aspheric test surface. The single-point profilometer measures surface height variations along one or more traces on the aspheric test surface. At least one of the traces intersects at least one of the areas, and respective spatial frames of reference for the traces and areas are relatively adapted to each other by minimizing differences between points of nominal coincidence between the areas and traces.

Description

technical field [0001] The present invention relates to the measurement of aspheric surfaces using a combination of optical measurement techniques in the field of optical metrology, and thus, in particular to both optical wavefront sensing and single-point profilometry, and the integration of measurements by such techniques . Background technique [0002] Measuring aspheric surfaces, which can generally be defined as surfaces distinct from planar, cylindrical, and spherical surfaces, presents many challenges compared to surfaces of simpler form. Despite the added difficulty of measuring them, aspheric surfaces must often be measured with a precision similar to that of simpler forms of surfaces. A particular problem with measuring aspheric surfaces is the large variation in local curvature and slope of the aspheric surface, which can be difficult to capture and compare to a datum. [0003] In conventional surface measurement techniques, optical wavefront sensing typically p...

AI Technical Summary

Problems solved by technology

Measurement of multiple axes is difficult to achieve the required accuracy and measurement of a large number of individual points covering the test surface with sufficient resolution is time consuming

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