Lens molds with coating
View Patent ↗The present invention generally relates to a contact lens forming mold and to a method of producing contact lenses with higher production yield and improved quality. By coating a contact lens forming mold with a nano-structured fluorine-containing inorganic polycondensate coating solution the number of lens holes, such as voids or areas of non uniform thickness of a contact lens therein produced is substantially decreased.
1. A contact lens forming mold, the mold having a center, and the mold comprising two mold halves, female and male mold halves, wherein at least one mold halt comprises a nano-structured fluorine-containing inorganic polycondensate coating which decreases wettability by a polyvinyl alcohol prepolymer lens forming material dosed into the mold thereby retarding spreading of the lens forming material towards the center of the mold.
2. A contact lens forming mold of claim 1 wherein the first and second mold halves, independently of each other, is made of glass or quartz.
3. A coating of claim 1 wherein the coating is on the female mold half.
4. A contact lens forming mold of claim 1 wherein the coating comprises polycondensates of one or more compounds of elements M of the main groups III to V and the subgroups II to IV of the periodic system of elements, said compounds being capable of hydrolytic polycondensation, whereby in these polycondensates, at least one organic group G having at least 2 aliphatic carbon atoms to which at least one fluorine atom is bonded to at least part of at least one central atom of element M either via one of the carbon atoms or via a linking group A.
5. A contact lens forming mold of claim 4 wherein the element M is selected from the group consisting of silicon, aluminium, boron, tin, zirconium, titanium, vanadium and zinc.
6. A contact lens forming mold of claim 4 wherein the element M is selected from the group consisting of silicon, aluminium, boron, zirconium, and titanium.
7. A contact lens forming mold of claim 4 wherein the element M is silicon.