Method and apparatus providing singlet wafer lens system with field flattener
View Patent ↗Methods and apparatus to correct a curved Petzval focusing surface to a plane using a convex lens, a concave lens, and a space arranged between the curved side of the convex lens and the curved side of the concave lens. The method and apparatus may also include a Fresnel lens arranged between the concave lens and a pixel array.
1. A lens structure, comprising:
a first convex lens comprising a first curved side and a first flat side;
a concave lens comprising a second curved side and a second flat side, the second curved side of the concave lens being arranged to face the first curved side of the first convex lens;
a first space arranged between the first curved side of the first convex lens and the second curved side of the concave lens; and
a Fresnel lens comprising a third flat side and a side comprising a faceted structure, the third flat side of the Fresnel lens being arranged to face the second flat side of the concave lens.
2. The lens structure of claim 1 , further comprising a third substrate arranged between the concave lens and the Fresnel lens.
3. The lens structure of claim 1 , wherein the first convex lens, concave lens, and Fresnel lens have substantially the same index of refraction.
4. The lens structure of claim 1 , wherein the first convex lens, concave lens, and Fresnel lens comprise a polymer material.
5. The lens structure of claim 1 , wherein the faceted structure of the Fresnel lens comprises a plurality of concentric facets, each of the facets having a first side and a second side.
6. The lens structure of claim 5 , wherein facets located closer to a center of the faceted structure are wider than facets located farther from the center of the faceted structure.
7. The lens structure of claim 6 , wherein all of the facets have the same depth.
8. The lens structure of claim 5 , wherein facets located farther from a center of the faceted structure are deeper than facets located closer to the center of the faceted structure.
9. The lens structure of claim 8 , wherein all of the facets have the same period.
10. The lens structure of claim 5 , wherein the first side of the facets is arranged to be perpendicular to a light ray having a chief ray angle able to reach a particular facet.
11. The lens structure of claim 5 , wherein the second side of the facets is arranged to be parallel to a light ray having a chief ray angle still able to reach a particular facet.
12. The lens structure of claim 5 , wherein the first side of the facets comprise a convex curve.