Coopervision, Inc.

Timothy J Warren

Albert H Morland

Disclosed is a process for casting lenses using male and female mould halves, which comprises placing a polymerizable liquid composition into the female mould half, introducing a male mould into the female mould along a substantially vertical axis until the male mould touches the surface of the liquid composition and then allowing the male mould to fall under its own weight into the female mould half and curing or allowing the polymerizable composition to cure. Also included is apparatus suitable for carrying out the casting process which comprises a substantially horizontal support for the female mould, a holder for releasably holding the male mould, means for moving the holder towards and into the female mould along a substantially vertical path passing through the axes of the moulds and means for detecting contact between the male mould and the surface of the liquid composition and causing said holder to release the male mould. Preferably, the moulds are formed from a thermoplastic material and are maintained under a predetermined closing pressure by spot welding the flanges.

Process for casting lenses

A process for casting lenses using male and female mold halves, which includes placing a polymerizable liquid into the female mold, introducing the male mold down into the female mold until the male mold touches the surface of the liquid and then allowing the male mold to fall into the female mold. Also, an apparatus suitable for carrying out the casting process is provided which includes a horizontal support for the female mold, a holder for releasably holding the male mold, a mechanism for moving the holder down towards and into the female mold and a mechanism for detecting contact between the male mold and the surface of the liquid and causing the holder to then release the male mold. The molds are maintained under a predetermined closing pressure during curing by spot welding their flanges together while under that pressure.

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Bursledon, United Kingdom

Timothy J Warren