| 摘要 |
An apparatus for molding polystyrene mold halves which are used, with a complementary mold halves, for subsequent molding of a soft contact lens such as a hydrogen soft contact lens. The apparatus is designed with superior heat conduction capacity so as to minimize the molding cycle time, while simultaneously producing uniformly precise and accurate optical quality surfaces. Molten polystyrene is provided via a hot runner system to a plurality of mold cavities, each of which is defined by first and second structural elements, the first having a convex surface and the other having a concave surface. In a specific variation, the convex surface provides the optical quality surface to the concave surface of the mold half produced thereby. The structural element which defines the convex surface includes a hollow cylindrical bushing and a removable power insert mounted therein, which may be changed so that the prescription strength of the contact lens to be formed by the mold may be varied. In a first embodiment, the power insert includes only a convex surface at its operational end. |
