Fresnel Collimator?

thingiverse

Attempt at a lens based on a squashed sphere, then manually sliced as a rudimentary Fresnel lens arrangement. To get this close to optically clear, the 3D print would be used as the basis for making a silicon release mold, and the actual lens cast in resin. Well, now that the suggestion is there, I suppose figuring out the rest is up to you.