Lens blanks with aligned polarizer

摘要

A thermoformed plastic laminar light-polarizing composite lens blank is produced from a laminate comprising a light-polarizing layer between polymeric layers. The absorption axis of the light-polarizing layer of the laminate is aligned to substantial parallelism with a principal index of refraction of the polymeric layer which forms the convex surface of the lens blank and which is birefringent, thereby to minimize retardation effects of the birefringent material on plane polarized light. The polymeric layer which forms the concave surface of the lens blank is substantially thicker than the opposed polymeric layer in order to accommodate grinding of the surface thereof to an ophthalmic prescription. Thermoforming of unitary portions cut from a supply of the laminate is performed under heat and pressure.