Reusable lens molds and methods of use thereof
View Patent ↗The present invention general related to a method and a reusable mold for making a contact lens, comprising a first mold half having a first mold surface in contact with a silicone containing lens forming composition and a second mold half having a second mold surface in contact with the lens forming composition. The first mold half and the second mold half are configured to receive each other such that a cavity is formed between the first mold surface and the second mold surface, wherein the cavity defines the shape of a contact lens to be molded. The lens forming composition is polymerizable and/or crosslinkable by a UV radiation, wherein at least one of the mold halves is made from an oxide glass material having a UV transmission cut-off wavelength no less than 390 nm and a specific gravity higher than 3.5.
1. A method for producing a contact lens, comprising: the steps of:
(1) providing a contact lens reusable mold, wherein the mold comprising a first mold half having a first mold and a second mold half having a second mold surface, wherein the first mold half and the second mold half are configured to receive each other such that a cavity is formed between the first mold surface and the second mold surface, wherein the cavity defines the shape of a contact lens to be molded, wherein at least one of the mold halves is made from a UV absorbing glass material having a UV transmission cut-off wavelength no less than 390 nm and a specific gravity higher than 3.5,
(2) introducing a silicone containing lens-forming composition into the cavity formed by the first and second molding surfaces, material, wherein the lens-forming material is crosslinkable and/or polymerizable by actinic radiation;
(3) crosslinking/polymerizing the lens-forming material in the mold to form a lens having a polymer matrix;
(4) opening the mold and removing the formed contact lens from the mold, wherein the formed contact lens has a clean lens edge without flash.
2. The method for producing a contact lens according to claim 1 , wherein the UV absorbing glass material comprising of a heavy metal oxide formed from Tellurium (Te), Lead (Pb), Tantalum (Ta), Bismuth (Bi), Antimony (Sb), and combinations thereof.
3. The method for producing a contact lens according to claim 1 , wherein the UV absorbing glass material has a refraction index higher than 1.9.
4. The method for producing a contact lens according to claim 1 , wherein the UV absorbing glass material having a UV transmission cut-off wavelength no less than 410 nm.
5. The method for producing a contact lens according to claim 1 , wherein the reusable mold is made by precision press molding.
6. The method for producing a contact lens according to claim 1 , wherein the reusable mold is made by single point diamond turning.