초록 ▼

The present invention encompasses, in part, a method and apparatus for lens casting in which two molds, preferably formed of plastic, are interconnected or joined together via a ring to form a mold cavity having substantially the same dimensions of the lens to be formed therein. In one implementatio

The present invention encompasses, in part, a method and apparatus for lens casting in which two molds, preferably formed of plastic, are interconnected or joined together via a ring to form a mold cavity having substantially the same dimensions of the lens to be formed therein. In one implementation the invention includes a the casting device comprising a plurality of front molds, each front mold formed of a plastic and having a lens-forming surface. The front molds are configured to form a plurality of lenses of different effective diameters. The casting device further includes a rear mold formed of a plastic and having a lens-forming surface; wherein the rear mold is configured to be paired with each of the plurality of front molds to form a plurality of lenses of different effective diameters.

대표청구항 ▼

What is claimed is: 1. A casting device, comprising: a. a ring having an interior periphery; b. a plurality of front molds, each front mold formed of a plastic and having a lens-forming surface, and the front molds providing an edge circumscribing the lens-forming surface that is sized to be comple

What is claimed is: 1. A casting device, comprising: a. a ring having an interior periphery; b. a plurality of front molds, each front mold formed of a plastic and having a lens-forming surface, and the front molds providing an edge circumscribing the lens-forming surface that is sized to be complementarily received within a portion of the interior periphery of the ring, and a base having dimensions greater than the interior periphery; and c. a rear mold formed of a plastic and having a lens-forming surface, the rear mold configured to be paired with each of the plurality of front molds, a rim circumscribing the lens-forming surface that is sized to be complementarily received within a portion of the interior periphery of the ling, and a flange having dimensions greater than the interior periphery; wherein when the edge of each of the front molds and the rim of the rear mold are configured to be received by the ring, the lens-forming surfaces of the front and rear molds and the ring form a mold cavity which has dimensions of a desired lens formable therein; and wherein the plurality of front molds are configured to form lenses of different effective diameters. 2. The casting device of claim 1, wherein the ring comprises plastic. 3. The casting device of claim 1, wherein the ring further defines a feed opening and a vent opening therethrough in fluid communication with the mold cavity. 4. The casting device of claim 3, wherein, when the front and rear molds are disposed upright, the vent opening is positioned at substantially the top center. 5. The casting device of claim 3, wherein the mold cavity is substantially is substantially circular in plan view and the feed opening is offset from the vent opening between approximately fifteen to ninety degrees. 6. The casting device of claim 2, wherein the ring has opposed ends, wherein the base of the front mold has a contacting surface that is substantially planar, and wherein the contacting surface and one end of the ring abut when the mold cavity is formed. 7. The casting device of claim 6, wherein the lens-forming surface of the front mold is concave and defines a nadir, wherein the nadir tangentially intersects a plane defined by the contacting surface of the base. 8. The casting device of claim 7, wherein the flange of the rear mold has an engaging surface that is substantially planar and wherein the engaging surface and one end of the ring abut when the mold cavity is formed. 9. The casting device of claim 8, wherein the lens-forming surface of the rear mold has an apex so that a plane tangential to the apex is substantially parallel to and spaced apart from a plane defined by the engaging surface, the separation between the plane tangential to the apex and the plane defined by the engaging surface is the back mold apex height. 10. The casting device of claim 9, wherein the ends of the ring are spaced apart by a ring height, the ring height being the sum of the back mold apex height and a desired center thickness for the mold cavity. 11. The casting device of claim 8, wherein the lens-forming surface of the front mold further comprises a plurality of protrusions each located adjacent the edge, the protrusions having a height corresponding to a desired edge thickness for the mold cavity. 12. The casting device of claim 1, wherein the front mold is rotatable relative to the rear mold so that the two molds are at one of a plurality of selected rotational orientations relative to each other so as to alter characteristics of the mold cavity when the lens-forming surfaces of the respective front and rear molds have asymmetric curvature.