Photochromic lens
View Patent ↗A cast photochromic lens including a photochromic film and a cast resin, curable by heat or radiation.
1. A cast photochromic lens comprising:
a photochromic film interposed between two portions of a single cast resin substrate;
wherein said photochromic film comprises at least one protective layer distinct from said cast resin substrate and a photochromic polyurethane layer, said photochromic polyurethane layer prepared from a composition comprising:
a solid thermoplastic polyurethane prepared from a composition comprising at least one diisocyanate;
an isocyanate-terminated polyurethane prepolymer; and
a photochromic compound;
said photochromic polyurethane layer having a top side and a bottom side, said at least one protective layer being bonded to at least one side of said photochromic polyurethane layer.
2. The lens of claim 1 , wherein said photochromic film comprises a thickness of less than 40 mil.
3. The lens of claim 1 , wherein said cast resin substrate comprises a thermoset resin.
4. The lens of claim 1 , wherein said cast resin substrate comprises a radiation-set resin.
5. The lens of claim 1 , wherein said at least one protective layer comprises a resin selected from a group consisting of: acrylate resins, cellulose esters and polycarbonate resins.
6. A cast photochromic lens comprising:
a first cast resin,
a second cast resin; and
a photochromic film placed therebetween, said photochromic film prepared from a composition comprising:
a solid thermoplastic polyurethane prepared from a composition comprising at least one diisocyanate;
an isocyanate-terminated polyurethane prepolymer; and
a photochromic compound;
said first cast resin and said second cast resin formed of a same resin.
7. The lens of claim 6 , wherein said photochromic film comprises materials having a glass transition temperature of less than 50° C.
8. The lens of claim 6 , wherein said photochromic film comprises materials having a glass transition temperatures of less than 30° C.
9. The lens of claim 6 , wherein said isocyanate-terminated polyurethane prepolymer has a molecular weight of about 1000 to 6000 g/mol.
10. The lens of claim 6 wherein said thermoplastic polyurethane has a molecular weight of about 9,000 to 100,000 g/mol.
11. A cast photochromic lens comprising:
a photochromic film having a first side and a second side, the photochromic film comprising at least one protective layer and a photochromic layer;
a first cast resin substrate molded to the first side of the photochromic film; and
a second cast resin substrate molded to the second side of the photochromic film;
wherein said first and second cast resin substrates are formed of a same resin and wherein the resin is distinct from said at least one protective layer; and
wherein said photochromic layer is prepared from a composition comprising:
a solid thermoplastic polyurethane;
an isocyanate-terminated polyurethane prepolymer; and
a photochromic compound.
12. A lens according to claim 11 wherein the photochromic layer comprises a photochromic polyurethane.
13. A lens according to claim 11 wherein the photochromic film has a thickness of no greater than 40 mil.
14. A lens according to claim 11 wherein said first and second cast resin substrates comprise a thermoset resin.
15. A lens according to claim 11 wherein said first and second cast resin substrates comprise a radiation-set resin.
16. A lens according to claim 11 wherein the protective layer comprises a resin selected from a group consisting of: acrylate resins, cellulose esters and polycarbonate resins.
17. A lens according to claim 11 wherein the photochromic film comprises a material having a glass transition temperature of less than 50 degrees Celsius.
18. A lens according to claim 11 wherein the photochromic film comprises a material having a glass transition temperatures of less than 30 degrees Celsius.
19. A lens according to claim 11 wherein the photochromic layer is interposed between two protective layers.
20. A lens according to claim 11 wherein the photochromic lens further comprises a layer selected from a group consisting of: adhesion layer, polarizing layer, hard-coating layer, primer layer, and barrier layer.