Patent attributes
A curved Fresnel lens is provided. The Fresnel lens includes a grooved surface and a smooth surface. The grooved surface includes a plurality of concentric sloped facets and a plurality of concentric draft facets. Pairs of concentric draft facets and concentric sloped facets form a plurality of concentric grooves in the grooved surface. The concentric sloped facets are configured to focus light toward an eye of a nominal user. At least some of the concentric draft facets are congruent with conical surfaces of respective imaginary light cones that have corresponding vertices that originate from respective focal points, wherein each imaginary light cone extends through the Fresnel lens at an angle based in part on an index of refraction of the Fresnel lens and extends beyond the grooved surface into free space.
