COATING MATERIAL FOR LENSES

摘要

A material particularly used for protecting a lens surface against scratching comprises a solution containing nitrocellulose in solvent the nitrocellulose being present in the solvent in the range 2.5% to 3.8% by weight. When the material is applied to a lens a coating adheres to the lens in which nitrocellulose is the principal constituent. This coating protects the lens against scratching during manufacture and enables traditional manufacturing processes to be applied for identifying and marking the focal centre of the lens blank prior to shaping the periphery of the blank because the coating does not disguise the optical properties of the lens.