Patent ID: 7450308
Filing Date: 2008-11-11
Classification: G11B

Abstract:
1. A beam shaping lens for shaping an incident beam having an elliptic cross section into an outgoing beam having a substantially circular cross section, comprising: a plane of incidence which is a cylindrical surface having a generating line curving to form a non-circular cylindrical surface as an incidence side of the incident beam; and an outgoing plane which is a circular cylindrical surface as an outgoing side of the outgoing beam, wherein: a distance between both ends of the generating line of the circular cylindrical surface is larger than a distance between both ends of the generating line of the non-circular cylindrical surface, (A) the plane of incidence is curving convexly against an incidence direction of the incident beam, and the outgoing plane is curving concavely against the outgoing direction of the incident beam, (B) the circular cylindrical surface of the outgoing plane is provided so as to have its generating line intersect with all optical paths of a ray of light made by the incident beam refracted on the plane of incidence.