Non-planar illumination sources for deflectometry

Abstract

We introduce the design of a highly compact, non-planar illumination source for deflectometry. The source emits uniform and Lambertian light from a curved area resembling the inner bore of a cylinder. When equipped with motion hardware, the ring source behaves like a spatially modulated screen with a pixel pitch comparable to that of a typical LCD monitor. If this source, a detector, and test optic are coaxially aligned, then on-axis deflectometry measurements are possible for axicons and centrally obscured, convex optics. This paper highlights the illumination design behind a cylindrical ring source and its implementation as a prototype in the visible spectrum.