Patent ID: 6638451
Filing Date: 2003-10-28
Classification: B29C,B29D,B29K,B29L,Y10S

Abstract:
A process for the production of an ophthalmic moulding, comprising:(1) introducing a lens material into a cavity formed by a mould, wherein the material is polymerisable and/or crosslinkable upon irradiation with UV light having a wavelength of greater than 280 nm and is in at least partly uncrosslinked condition, wherein the mould has a first mold half defining a first optical surface and an UV-absorbable second mold half defining a second optical surface, wherein said first mold half and said UV-absorbable second mold half are configured to receive each other such that the cavity is formed between said first optical surface and said second optical surface, wherein the first mold half is transparent to the UV light, wherein the UV-absorbable second mold half comprises a polymer whose oxygen permeability is less than 5Ã—10-11&it;(ml&it;â€ƒ&it;O2&it;â€ƒ&it;at&it;â€ƒ&it;STP)&it;â€ƒ&it;(mm)(cm2)&it;â€ƒ&it;(s)&it;â€ƒ&it;(torr),and wherein the UV-absorbable second mold half can substantially reduce the reflection of the UV light by the UV-absorbable second mold half; and(2) Crosslinking the lens material under a spatial limitation of UV irradiation to form the ophthalmic moulding having a first surface, an opposite second surface, and an edge, wherein the spatial limitation of UV irradiation is provided by a mask, wherein the first surface is defined by the first optical surface, the second surface is defined by the second optical surface, and the geometry of the edge is defined by the spatial limitation of UV irradiation, and wherein the use of the UV-absorbable second mold half reduces substantially the crosslinking, induced by reflected UV light, of lens material around the actual edge so that the quality of the edge is improved.