Scanning laser demolding of ophthalmic lenses

摘要

An apparatus and method for removing a molded ophthalmic lens from between the mold portions in which it is produced. A source of intense electromagnetic radiation is applied to at least one of the mold portions in a predetermined scanning pattern through the intermediary of galvanometer-driven mirrors. Differential expansion of the heated mold polymer relative to the cooler polymer shifts one surface with respect to the other, and the shear force breaks the polymerized lens/polymer mold adhesion and assists in the separation of mold portions. The greater the temperature gradient between the surfaces of the mold portions, the greater the shearing force and the easier the mold portions separate. The heated back mold portion is promptly removed so that very little energy is transferred to the polymer lens, avoiding the possibility of thermal decomposition of the lens.