Injection molding of lens
View Patent ↗A flat or curved photochromic laminate structure and a plastic photochromic lens blank can be produced in a simple and efficient manner from relatively low-cost polymeric sheet materials. These laminates can be used to provide goggles, face shields, windows, window coverings, skylights, and optical lenses having efficient, uniform and high quality photochromic properties. The use of a polyesterurethane as the binder for the photochromic material has been found to improve the performance of the photochromic material. There may be a desire to have a protective exterior layer (e.g., an abrasion resistant layer) in combination with the lens system, but that may be provided in various methods. In the case of using the laminate in a goggle application, the laminate may be hard coated on one or both outer surfaces with an abrasion resistant coating, antireflective coating, and/or an anti-fog hard coating.
1. A method of forming an ophthalmic lens comprising:
providing a mold having a concave portion and a convex portion, said mold also having a portion for forming an add corridor in a multifocal lens;
providing a laminate functional film;
placing said laminate functional film in said mold, wherein prior to the placing of said laminate functional film in said mold, said laminate functional film has been pre-shaped to a shape shallower than a surface in said mold into which said laminate functional film is being placed;
injecting a molten thermoplastic into said mold at a location adjacent to said portion for forming said add corridor;
maintaining a temperature of said mold within a range of approximately 270–290 degrees F. during the injection of said molten thermoplastic;
allowing said thermoplastic to cool; and,
removing the resulting ophthalmic lens having said laminate functional film from said mold.
2. A method according to claim 1 , wherein providing a laminate functional film includes providing a photochromic functional film.
3. A method according to claim 2 , wherein providing a photochromic functional film includes providing a photochromic layer having a polyester urethane binder and a photochromic compound, the photochromic layer adhered to one surface of a polymeric layer comprising a polycarbonate resin or a polysulfone resin.
4. A method according to claim 1 , wherein prior to placing said laminate functional film in said mold, the laminate functional film is preformed so that it is within the range of more than zero diopters and less than 4 diopters in curvature.
5. A method according to claim 1 , wherein prior to placing said laminate functional film in said mold, said laminate functional film is pretreated using at least one of the following pretreatments: heat, vacuum and dessication.
6. A method according to claim 1 , wherein the injecting of a molten thermoplastic into said mold includes injecting molten polycarbonate.
7. A method according to claim 1 , wherein the injecting of a molten thermoplastic into said mold includes injecting molten polysulfone.
8. A method of forming an ophthalmic lens comprising:
providing a mold having a concave portion and a convex portion said mold also having a segment for forming a stepped multifocal lens;
providing a laminate functional film;
placing said laminate functional film in said mold;
injecting a molten thermoplastic into said mold, wherein said molten thermoplastic is injected into said mold at a location as distant from said segment as practicable and wherein an edge of said segment encounters said molten thermoplastic prior to a remaining portion of said segment;
maintaining a temperature of said mold within a range of approximately 270–290 degrees F. during the injection of said molten thermoplastic;
allowing said thermoplastic to cool; and,
removing the resulting ophthalmic lens having said laminate functional film from said mold.
9. A method according to claim 8 , wherein providing a laminate functional film includes providing a photochromic functional film.
10. A method according to claim 9 , wherein providing a photochromic functional film includes providing a photochromic layer having a polyester urethane binder and a photochromic compound, the photochromic layer adhered to one surface of a polymeric layer comprising a polycarbonate resin or a polysulfone resin.
11. A method according to claim 8 , wherein prior to placing said laminate functional film in said mold, the laminate functional film is preformed so that it is within the range of 4 to zero diopters in curvature.
12. A method according to claim 8 , wherein prior to placing said laminate functional film in said mold, said laminate functional film is pretreated using at least one of the following pretreatments: heat, vacuum and dessication.
13. A method according to claim 8 , wherein the injecting of a molten thermoplastic into said mold includes injecting molten polycarbonate.
14. A method according to claim 8 , wherein the injecting of a molten thermoplastic into said mold includes injecting molten polysulfone.
15. A method of forming an ophthalmic lens comprising:
providing a mold having a concave portion and a convex portion, said mold also having a portion for forming an add corridor in a multifocal lens;
providing a laminate functional film;
placing said laminate functional film in said mold, wherein prior to the placing of said laminate functional film in said mold, said laminate functional film has been pre-shaped to a shape shallower than a surface in said mold into which said laminate functional film is being placed;
injecting a molten thermoplastic into said mold at a location adjacent to said portion for forming said add corridor;
maintaining a temperature of said mold within a predetermined temperature range during the injection of said molten thermoplastic;
allowing said thermoplastic to cool; and,
removing the resulting ophthalmic lens having said laminate functional film from said mold.
16. A method according to claim 15 , wherein providing a laminate functional film includes providing a photochromic functional film.
17. A method according to claim 16 , wherein providing a photochromic functional film includes providing a photochromic layer having a polyester urethane binder and a photochromic compound, the photochromic layer adhered to one surface of a polymeric layer comprising a polycarbonate resin or a polysulfone resin.
18. A method according to claim 15 , wherein prior to placing said laminate functional film in said mold, the laminate functional film is preformed so that it is within the range of more than zero diopters and less than 4 diopters in curvature.
19. A method according to claim 15 , wherein prior to placing said laminate functional film in said mold, said laminate functional film is pretreated using at least one of the following pretreatments: heat, vacuum and dessication.
20. A method according to claim 15 , wherein the injecting of a molten thermoplastic into said mold includes injecting molten polycarbonate.
21. A method according to claim 15 , wherein the injecting of a molten thermoplastic into said mold includes injecting molten polysulfone.
22. A method according to claim 15 , wherein said multifocal lens is a progressive multifocal lens.
23. A method according to claim 15 , wherein said multifocal lens is an aspheric multifocal lens.
24. A method according to claim 1 , wherein said multifocal lens is a progressive multifocal lens.
25. A method according to claim 1 , wherein said multifocal lens is an aspheric multifocal lens.
26. A method according to claim 1 , wherein providing a laminate functional film includes providing a polarizing film.
27. A method according to claim 15 , wherein providing a laminate functional film includes providing a polarizing film.
28. A method according to claim 2 , wherein providing a photochromic functional film includes providing a photochromic layer having a polyester urethane binder.
29. A method according to claim 16 , wherein providing a photochromic functional film includes providing a photochromic layer having a polyester urethane binder.