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Figure 8


Fig. 8. Diagram of a facet lens with obliquely incident light. A light ray parallel to the ray through the lens vertex, arriving at the facet lens margin has an angle of incidence {theta}m= {alpha}+{theta}l, where {theta}l=arctan(Dl/2Rl), with Dl the facet lens diameter and Rl the radius of the facet lens front surface.