Method and apparatus for the dry release of a compliant ophthalmic article from mold surface
An apparatus for releasing a molded lens from a deformable mold includes a shear ring for temporarily retaining an annular portion of the deformable mold outside a periphery of the lens and a plunger for deforming an annular section of the deformable mold within the periphery of the lens. The apparatus can be employed to release a non-hydrated hydrogel lens from a deformable mold section.
1. A method for releasing a compliant hydrogel molded lens from a concave mold surface of a deformable mold comprising locating a circular shear ring against an anterior surface of the concave mold at a location radially spaced from and surrounding the optical surface portion of the mold, contacting a posterior surface of the concave mold with a plunger having a raised annular lip on an end surface of the plunger, moving the shear ring and the plunger one towards the other and each pressing against the mold thereby deforming the mold in a manner that creates a shear force between the concave surface and the molded lens sufficient to effect the peeling of the molded lens from the concave mold surface wherein the peeling starts at an outer periphery of the molded lens and propagates to a center of the molded lens.
2. The method of claim 1 , further comprising hydrating the molded lens after peeling.
3. The method of claim 1 , further comprising releasing the molded lens from the concave mold surface prior to initially hydrating the lens.
4. The method of claim 1 , further comprising deforming the mold by fixing a portion of the deformable mold spaced radially beyond a periphery of the molded lens and deforming the concave mold surface to peel a portion of the molded lens from the deformable mold.
5. The method of claim 1 , further comprising continuously propagating the peeling from the outer periphery of the molded lens to the center of the molded lens.