Contact lens casting
AssigneePilkington Visioncare, Inc.
InventorsAshok Thakrar, Norman M. Van Houten, John M. Evans, Richard S. Skipper, Peter H. Stafford, John T. Phoenix
Life of this patent
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Abstract
Hydrophobic casting moulds are treated with electrical discharge, such as corona discharge, to provide enhanced compatibility with hydrophilic objects introduced into the mould, without interfering with the release properties of the mould. A preferred embodiment involves treatment of contact lens casting moulds with corona discharge to provide improvements in the lens manufacturing procedure, as well as enhancement in the quality of the contact lenses themselves. The invention is particularly applicable to the production of contact lenses having a colored iris pattern imprinted thereon.
Claims27
The method of producing a contact lens comprising the steps of treating a surface of a hydrophobic lens casting mould with electrical corona discharge, selecting an active material which is insoluble in the monomer material to be used in the lens, dispersing said active material in a hydrophilic carrier system which is compatible with said monomer material, using the resulting dispersion to coat the electrical corona discharge treated surface of said casting mould, introducing a hydrophilic monomeric lens forming liquid in said mould in contact with said coated surface, polymerizing said liquid to produce a lens blank having an active material impregnated in said blank, adjacent an optical surface thereof, and subsequently removing said lens from said mould.
The method of producing a coloured contact lens comprising the steps of treating the surface of a lens casting mould with electrical corona discharge, selecting a colouring material which is insoluble in the monomer material to be used in the lens, dispersing said colouring material in a carrier system which is compatible with said monomer material, using the resulting dispersion to imprint a pattern on a surface of a casting mould, introducing a monomeric lens forming liquid in said mould in contact with said imprinted surface, polymerizing said liquid to produce a lens blank having a coloured pattern impregnated in said blank, adjacent an optical surface thereof, and subsequently removing said lens from said mould.
The method of producing a coloured contact lens comprising the steps of treating the surface of a hydrophobic casting mould with electrical corona discharge, preparing a colouring dispersion comprising from 10 to 90% by weight of monomeric hydroxyethyl methacrylate and from 10 to 90% by weight of a colouring material which is insoluble in hydroxyethyl methacrylate, using the said dispersion to imprint a pattern on a surface of said treated casting mould, introducing additional hydroxyethyl methacrylate monomer in said mould in contact with said imprinted surface, polymerizing said monomer to produce a lens blank having a coloured pattern impregnated in said blank, adjacent an optical surface thereof, and subsequently removing said lens from said mould.
The method of producing a contact lens comprising the steps of treating a surface of a lens casting mould with electrical corona discharge, selecting an active material which is insoluble in the monomer material to be used in the lens, dispersing said active material in a carrier system which is compatible with said monomer material, using the resulting dispersion to coat the corona discharge treated surface of said casting mould, treating the coated surface of said lens casting mould with further electrical corona discharge, introducing a monomeric lens forming liquid in said mould in contact with said coated surface, polymerizing said liquid to produce a lens blank having an active material impregnated in said blank, adjacent an optical surface thereof, and subsequently removing said lens from said mould.
The method of producing a contact lens comprising the steps of treating a surface of a lens casting mould with electrical corona discharge, selecting a colouring material which is insoluble in the monomer material to be used in the lens, dispersing said colouring material in a carrier system which is compatible with said monomer material, using the resulting dispersion to imprint a pattern on a surface of said casting mould, introducing a monomeric lens forming liquid in said treated mould, polymerizing said liquid to produce a lens blank having a first optical surface thereon and a colour pattern impregnated therein, generating a second optical surface on said blank while said casting mould containing said blank is mounted on a precision mandrel, and subsequently removing said lens from said mould.
Dependencies are inferred from the claim text.