14 Nov 2013 - 14 Nov 2013
This webinar will describe the effects of surface slope errors – concentrating on the “mid spatial frequency” region – on image quality, and will describe methods for determining tolerances for surface slope. Optical surfaces are increasingly fabricated using modern machining techniques (diamond turning, magnetorheological finishing, and other forms of computer-controlled polishing), and these processes have different “error signatures” than traditional pitch polishing of spherical surfaces. Therefore, when specifying surfaces that will be fabricated by a machining technique, it is important to understand how these error types affect the image quality and to place some form of tolerance to ensure adequate performance from the system. Equally important, the tolerance should not be unnecessarily tight, as this will increase the fabrication cost without improving the performance in a meaningful way.