Patent ID: 6579476
Filing Date: 2003-06-17
Classification: B29C,B29D,B29L,Y10S

Abstract:
A method for molding a plastic ophthalmic lens using a two-piece mold, said two-piece mold defining a molding cavity having a vertical central axis which is part of a fixed reference system comprising said vertical axis and a horizontal central axis which intersects at the center of the mold, said horizontal central axis dividing the molding cavity into a lower half and an upper half, and comprising a filling nozzle for introduction of a liquid polymerizable monomer composition into the molding cavity and situated at the periphery of the upper half of the mold cavity, said method comprising:(a) starting introduction of the liquid polymerizable monomer composition into the molding cavity with the filling nozzle spaced apart from the vertical central axis of the mold cavity by a distance sufficient so that the liquid polymerizable monomer composition flows in a region of the molding cavity adjacent to the periphery thereof; (b) continuing introduction of the liquid polymerizable monomer while the filling nozzle is spaced from the vertical central axis until at least the lower half of the molding cavity is filled up; (c) moving relatively from each other the filling nozzle and the two-piece mold to bring the filling nozzle in register with the vertical central axis of the molding cavity; (d) continuing introduction of the liquid polymerizable monomer composition while the filling nozzle is as in step (c) until the molding cavity is fully filled; (e) stopping introduction of the liquid polymerizable monomer composition and polymerizing the composition; and (f) recovering the polymerized ophthalmic lens.