What's it about?
This paper will present designers with topics to consider during aspheric lens design. There are geometrical restrictions that hinder producing particular aspheric shapes. Understanding these restrictions will help drive cost out of the design.
1. Specifying a Clear Aperture
Independent of the aspheric surface shape (convex and or concave) the clear aperture diameter is smaller than the full diameter of the part. The behavior of the aspheric profile within both of these diameters and the associated actual edge thickness influences the manufacturing options as well as the price of the optic. The need to produce an over sized in-process mechanical diameter is, in most all cases, critical to successfully yielding the final product. It is common to process parts oversized by 4mm or more beyond the final clear aperture. Once polished the lens is then edged to the final diameter...