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. The cavity defines the shape of a contact lens to be molded. The lens forming composition is polymerizable and/or crosslinkable by actinic radiation. The reusable mold has at least one of the mold halves is made from chalcogenide glasses, Zinc Selenide or Zinc Sulfide.
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 chalcogenide glasses or Zinc Sulfide,
(2) introducing a silicone-containing lens-forming composition into the cavity formed by the first and second molding surfaces, 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 is characterized by having a clean lens edge without flash.
2. The method for producing a contact lens according to claim 1 , wherein the mold half is made from Zinc Sulfide.
3. The method for producing a contact lens according to claim 1 , wherein the mold half has a UV transmission cut-off wavelength no less than 350 nm.
4. The method for producing a contact lens according to claim 1 , wherein the mold half single point diamond turned to produce optical quality surfaces.
5. The method for producing a contact lens according to claim 1 , wherein the lens-forming composition comprises at least one components selected from the group consisting of a silicone-containing vinylic monomer, a silicone-containing vinylic macromer, a silicone-containing prepolymer, a hydrophilic vinylic monomer, a hydrophobic vinylic monomer, a crosslinking agent, a free-radical initiator (photoinitiator or thermal initiator), a hydrophilic vinylic macromer/prepolymer, and combinations thereof.
6. The method for producing a contact lens according to claim 5 , wherein the lens-forming composition further comprises at least one UV-absorbing vinylic monomer that absorbs ultraviolet light.
7. The method for producing a contact lens according to claim 6 , wherein the lens-forming composition further comprises at least one germanium-based Norrish Type I photoinitiator.
8. The method for producing a contact lens according to claim 1 , wherein the lens-forming composition is crosslinked and/or polymerized by UV LED in a region from 380 nm to 550 nm.
9. The method for producing a contact lens according to claim 7 , wherein the lens-forming composition is crosslinked and/or polymerized by UV LED with a total intensity from about 10 to about 100 mW/cm 2 in the region from 380 nm to 550 nm.
10. The method for producing a contact lens according to claim 7 , wherein the lens-forming composition is crosslinked and/or polymerized by UV LED with a total intensity from about 20 to about 60 mW/cm 2 in the region from 380 nm to 550 nm.
11. The method for producing a contact lens according to claim 7 , wherein the lens-forming composition is crosslinked and/or polymerized by UV LED in less than 120 seconds.