Patent ID: 9146384
Filing Date: 2015-09-29
Classification: G02B

Abstract:
1. An optical system for forming an image on a concave spherical surface comprising, perpendicularly to the optical axis of the spherical surface, starting from the object side: a first elliptical plano-convex lens, having a convexity turned towards the object side; a second aspherical plano concave lens having a radius of curvature decreasing with the distance to the axis, with the concavity of the second lens turned towards the image side, made of a material having an Abbe number smaller than that of the first lens; a parallel plate supporting the planar surfaces of the first and second lenses; and a third aspherical plano-convex/concave lens having a central portion with a convex shape, defining a convex portion, and a periphery with a concave shape, defining a concave portion; wherein the optical system captures the image and forms the image on the concave spherical surface.