Lens casting system
An optical lens casting gasket, wafer, and system and method that provides for more efficient formation of optical lenses employing optically functional wafers.
1. An optical lens mold gasket comprising:
a gasket body;
a groove disposed on an internal surface of said body, said groove sized for holding a wafer;
a vent port formed between an exterior side wall and an interior sidewall of said body and intersecting said groove; and,
a fill port on said body spaced from said groove and configured to direct a flow of mold material to one side of a wafer before said mold material flows to an opposite side of said wafer.
2. An optical lens mold gasket according to claim 1 wherein said fill port is formed through a sidewall of said gasket body between said groove and a back mold stop.
3. An optical lens mold gasket according to claim 1 wherein said groove is tapered.
4. An optical lens mold gasket according to claim 1 wherein said fill port comprises a tubular element extending from an exterior surface of said gasket body.
5. An optical lens mold gasket according to claim 1 further comprising a chamber in fluid communication with said vent port formed on an exterior of said gasket body.
6. An optical lens mold system comprising:
a mold;
a gasket associated with said mold;
a wafer associated said mold;
said gasket comprising:
a body;
a groove having an upper lip comprising at least one interrupted protrusion formed on an interior surface of the body and sized to receive said wafer and;
a fill port in a sidewall of said body;
said wafer shaped such that at least one space is created between a periphery of said wafer and a surface of said groove when said wafer is received in said groove;
said wafer forming a first and second cavity in said mold on opposite sides of said wafer, respectively, when said wafer is received in said groove; and,
said fill port being positioned on said sidewall of said body such that mold material introduced to said fill port is directed to said first cavity before flowing through said at least one space to said second cavity.
7. An optical lens mold system according to claim 6 wherein said wafer comprises an optical functional property selected from a group consisting of: polarization, photochromism, tint, color, hardness, chemical resistance, and reflectance.
8. An optical lens mold system according to claim 6 wherein said shape of said wafer in non-circular.
9. An optical lens mold system according to claim 6 wherein said gasket further comprises a vent port formed through a sidewall of said body, said vent port intersecting said groove.
10. An optical lens mold system according to claim 9 wherein the fill port and the vent port are axially spaced apart from each other.
11. An optical lens mold system according to claim 6 wherein said wafer is shaped to create multiple spaces between a periphery of said wafer and a surface of said groove when said wafer is received in said groove.
12. An optical lens mold system according to claim 6 wherein said fill port and said at least one space are configured so that mold material enters said second cavity exclusively through said at least one space.
13. A method of casting a lens comprising:
placing a wafer into a groove of a gasket associated with a mold such that the wafer forms a front cavity and a back cavity inside the gasket;
orienting the wafer into the groove such that the wafer is positioned against a vent port formed between an exterior side wall and an interior sidewall of the gasket and intersecting the groove;
introducing flowable lens material initially into said back cavity and not initially into said front cavity;
venting air from said front and back cavity during introduction of said flowable lens material initially into said back cavity.
14. The method of claim 13 further comprising directing said flowable lens material into said front cavity after said back cavity is substantially full through at least one space between said wafer and said mold.
15. The method of claim 14 further comprising directing said flowable lens material through a single space between said wafer and said mold.
16. The method of claim 14 wherein placing a wafer into a mold comprises placing a wafer having a non-circular periphery into said mold.
17. The method of claim 16 wherein said non-circular periphery of said wafer is received in a groove of said mold and thereby creates said at least one space between said wafer and said mold.
18. The method of claim 13 wherein said venting occurs at a location axially spaced from where said introducing of said flowable lens material occurs.
19. The method of claim 13 wherein said venting occurs through a vent port in said gasket.