Method of separating excess lens forming material from a molded ophthalmic lens, in particular a contact lens
There is described a method of separating excess lens forming material from a molded ophthalmic lens, in particular a contact lens. After polymerization and/or cross-linking of a lens forming material (P) within a mold cavity ( 4 ) of a mold ( 1 ) comprising female and male mold halves ( 2, 3 ) to form an ophthalmic lens non-polymerized and/or non-cross-linked lens forming material is flushed away from the mold halves ( 2, 3 ) with a jet of a fluid flushing medium, such as, e.g., water or a solvent or an inert gas. Subsequently the molded lens is dried. In accordance with the invention the flushing is accomplished with the mold halves ( 2, 3 ) still in the closed position. There is also described an apparatus for carrying out the method.
1. An apparatus for forming an ophthalmic lens, and separating excess lens forming material from the ophthalmic lens comprising a female and a male mold half which in a closed position define a mold cavity, and which are guided axially in a guide sleeve, the apparatus further comprising a feed channel and a discharge channel which open towards a feed port and a discharge port, respectively, at a circumference of the guide sleeve and are in connection with a peripheral zone of the mold cavity; and wherein the feed channel and the discharge channel extend tangentially to the peripheral zone of the mold cavity; and
wherein the feed channel and the discharge channels open to the peripheral zone of the mold cavity at opposite sides of a circumference of the mold cavity and wherein for flushing of the mold halves, a flushing medium is injected into the feed channel and wherein the flushing medium together with the excess lens forming material is discharged through the discharge channel while the mold halves are arranged in a closed position to separate excess lens forming material from the ophthalmic lens.
2. The apparatus according to claim 1 , wherein the feed channel and the discharge channel, respectively, are arranged in vicinity of separation planes of the female and male mold halves.
3. The apparatus according to claim 1 , wherein the feed channel and the discharge channel extend in a generally parallel direction.
4. The apparatus according to claim 1 , wherein at least the feed port has a cylindrical shape and is adapted such, that upon insertion of a conical tip of a feed line a sealing is achieved.
5. The apparatus according to claim 2 , wherein at least the feed port has a cylindrical shape and is adapted such, that upon insertion of a conical tip of a feed line a sealing is achieved.