Optical sheet for use in manufacturing a cylindrically shaped optically correct visor and method of manufacturing said visor

摘要

A plano-convex optical sheet having a positive power including: a substantially planar inner surface; opposed lateral edges, and a thickness s that is decreasing proceeding from a transversal central line passing through the geometric center of the optical sheet towards said opposed lateral edges along a portion of predetermined width w of the optical sheet, so as to define a convex outer surface having a curvature such that the optical sheet is capable of providing once bent a cylindrically shaped optically correct visor.