Three-dimensional printing of optical devices
The present application discloses a method for three-dimensional deposition printing to manufacture optical elements including ophthalmic devices by controlling the level of oxygen in the polymerization mixture and the printing environment to achieve precision in form and smoothness of surface for image quality optical performance.
1. A method for three-dimensional deposition printing of an optical element, in which method a plurality of droplets of a polymerizable mixture are deposited onto a surface of a substrate under a controlled atmosphere thereby forming successive layers of droplets of the polymerizable mixture, wherein the controlled atmosphere has an oxygen concentration of up to 5.0 volume-%, and wherein the polymerizable mixture has an oxygen equilibrium concentration that is up to 8.0 volume-%.
2. The method according to claim 1 , wherein the oxygen concentration in the controlled atmosphere is at up to 2.0 volume-% and/or lower than the oxygen equilibrium concentration in the polymerizable mixture.
3. The method according to claim 1 , further comprising exposing said successive layers of droplets to actinic radiation after deposition of each layer and after the deposition of a final of the successive layers of droplets for forming the optical element; optionally wherein the successive layers of droplets achieve partial polymerization or gelation to allow subsequent droplets and layers to meld and form distortion free structures.
4. The method according to claim 1 , wherein the polymerizable mixture contains one or more polymerization initiators.
5. The method according to claim 4 , further comprising a curing process wherein a first polymerization initiator is used in partially curing the successive layers, and a second polymerization initiator is used to complete the curing process.
6. The method according to claim 1 , wherein said surface of said substrate is pre-treated with a surface active agent or by plasma treatment prior to deposition of the first of the successive layers.
7. The method according to claim 1 , wherein the optical element is subsequently released from the substrate.
8. The method according to claim 1 , wherein the polymerizable mixture comprises methacrylate or acrylate monomers, optionally wherein the monomers are selected from hydroxyethyl methacrylate (HEMA) and hydroxyethyl acrylate (HEA), and optionally wherein the method comprises the subsequent step of swelling the optical element in water, whereby the optical element obtains a water content from 10 to 80 weight-%.
9. The method according to claim 1 , wherein the polymerizable mixture comprises reactive silicone monomers or oligomers, optionally wherein the method comprises the subsequent step of swelling the optical element in water, whereby the optical element obtains a water content from 5 to 70 weight-%.
10. The method according to claim 1 , wherein the polymerizable mixture after polymerization provides a polymer which is non-swellable in water.
11. The method according to claim 1 , wherein the polymerizable mixture of one or more of the layers of droplets comprises a pigment.
12. The method according to claim 1 , wherein the polymerizable mixture includes one or more cross-linkers in an amount of 0.5 to 5.0 weight-%, one or more non-reactive diluents in an amount of 0 to 60.0 weight-%, and one or more polymerization inhibitors in an amount of less than 100.0 ppm, based on the weight of the polymerizable mixture.
13. The method according to claim 1 , wherein the optical element is an ophthalmic device selected from a spectacle lens, a contact lens, an overlay lens, an intraocular lens, a corneal implant, and an ophthalmic/ocular insert; optionally wherein the ophthalmic device is a contact lens to correct refractive errors in keratoconus and astigmatic corneas.
14. The method according to claim 13 , wherein the ophthalmic device has an asymmetrical design.
15. The method according to claim 1 , wherein the optical element comprises one or more objects embedded therein; optionally wherein the one or more objects includes a solid object selected from inserts, electronics, and functional additive releasing reservoirs or depots.
16. The method according to claim 15 , wherein the optical element is a soft contact lens which has a rigid embedded insert to mask astigmatism.
17. The method according to claim 1 , wherein the optical element comprises one or more functionally active substances including biologically active substances.
18. The method according to claim 1 , wherein the optical element is formed through a plurality of print heads with the first print head dispensing droplets of a first polymerizable mixture and one or more additional print head(s) each dispensing droplets of compositions selected from the first polymerizable mixture, a second polymerizable mixture which is compositionally different from said first polymerizable mixture, and a non-polymerizable mixture.
19. The method according to claim 18 , wherein said first and/or second polymerizable mixture comprise functionally active substances, and/or wherein said non-polymerizable mixture comprises functionally active substances.
20. The method according to claim 1 , wherein the substrate is an ophthalmic device of which one or more surfaces functions as the substrate.
21. The method according to claim 4 , wherein the one or more polymerization initiators are selected from thermal initiators and photo-initiators.
22. The method of claim 4 , wherein the photo-initiators have responsiveness to different wavelengths of actinic radiation.