Patent ID: 8088313

Claim:
A process for producing contact lenses, comprising the steps of: (a) introducing a liquid starting crosslinkable material into a mold, wherein the starting crosslinkable material comprises at least one member selected from the group consisting of a polymerizable monomer, a polymerizable oligomer, a polymerizable prepolymer, a crosslinkable polymer and mixtures thereof and dissolved in a suitable solvent, wherein said mold comprises a first mold half having a first molding surface, a second mold half having a second molding surface, and at least one mask, wherein when the mold is closed the first and second molding surfaces together define a mold cavity, wherein the first and second mold halves do not touch within the mold cavity, wherein at least one of the first and second mold surfaces is permeable to a crosslinking energy suitable to cause the crosslinking of the starting crosslinkable material, wherein the mask is located on the mold half having an energy-permeable mold surface and is impermeable or at least of poor permeability compared with the permeability of the energy-permeable mold surface, wherein the mask extends inwardly right up to the mold cavity to form a boundary contour with the mold cavity so as to screen all areas behind the mask with the exception of the mold cavity; (b) providing the crosslinking energy in a form of a substantially parallel beam; (c) irradiating with the crosslinking energy the mold containing the starting material from the mold half having the mask located thereon so as to spatially restrict the crosslinking energy to be impinged to the mold cavity in an energy-impinging region, wherein the energy-impinging region is defined by combination of the first and second molding surfaces and an imaginary wall extending between the first and second molding surfaces and surrounding the mold cavity, wherein the imaginary wall is formed by transferring the boundary contour with the mold cavity of the mask in a two-dimensionally parallel and downwards manner from one mold surface to the other mold surface, thereby causing essentially only the starting crosslinkable material located inside the energy-impinging region to be crosslinked to a degree sufficient to form a contact lens capable of being released from said mold, wherein the produced contact lens comprises a first surface defined by the first molding surface, an opposite second surface defined by the second molding surface, and a clean and burr-free rim which does not require any subsequent mechanical processing and at least partial areas of which are defined by the imaginary wall which is defined by the boundary contour of the mask with the mold cavity; and wherein the mask is located in the region of separating planes or separating faces of the mold halves.