Patent ID: 9158109
Filing Date: 2015-10-13
Classification: G02B

Abstract:
1. An optical system comprising: an optical reflecting element having a surface with an aspherical shape, the optical reflecting element having a principal axis perpendicular to the surface and intersecting the surface at a vertex thereof, the surface further being rotationally asymmetric around the principal axis; wherein the optical reflecting element is optically coupled to receive an incident beam, the incident beam having an incidence angle with respect to the surface; wherein the surface has an in-plane radius of curvature that spatially varies in an in-plane direction, the in-plane direction corresponding to a plane including the incident beam and the perpendicular to the surface at an incidence point; wherein the optical reflecting element has an in-plane cross section surface profile in the in-plane direction that is characterized in that the multiplication of the cosine of the incidence angle raised to a non-zero exponent by the in-plane radius of curvature varies less than twenty percent between any two points on the in-plane cross section surface profile; and wherein the in-plane radius of curvature is defined by ([1+y′