METHODS OF TOLERANCING AN OPTICAL SURFACE USING A LOCAL PUPIL REGION

摘要

A method of tolerancing an optical surface of a lens element of an optical system based on an interferogram of the optical surface is disclosed. The method includes defining for the optical surface a local pupil region having a corresponding field point in the image plane; defining a tolerance T on a feature of the optical surface within the local pupil region based on a performance metric of the optical system for the field point; fitting a polynomial to surface topography of the interferogram over the local pupil region to obtain a coefficient C that relates the optical surface feature to the performance metric; and comparing the tolerance T to the coefficient C to establish whether C < T for the field point. The process can be repeated for different local pupil region locations relative to the interferogram to tolerance the entire optical surface.