Verfahren zur Herstellung eines aspherischen, bifokalen Formteils, für die Herstellung von Kunststofflinsen

摘要

A method of making a concave aspheric mold insert by electroplating nickel over a silver release agent coating on an aspheric surface formed in a copper substrate to form a master having a convex surface which is a negative image of the aspheric surface. After the master has been separated from the substrate its convex surface is coated with a silver release agent and electroplated with nickel to form an element having a concave surface which is a replication of the aspheric surface and the opposite surface of which is convex. After the convex surface of the element has been trued to spherical shape, a slightly oversize spherical D-seg is formed in the aspheric surface. The aspheric surface is then trued to reduce the D-seg to final size to produce the insert. A number of elements are formed from the master and are provided with D-segs of different radii. In an alternative method the D-seg is formed in the spherical concave surface of a glass substrate, the spherical concave surface of which has the best fit to the desired aspheric surface.