Apparatus and method for producing center gated lens molds for contact lens manufacture
AssigneeJohnson & Johnson Vision Products, Inc.
InventorsThomas A. Matiacio, Keith T. O'Brien, Victor Lust, Jeffrey H. Roffman, Kornelis Renkema, Wybren van der Meulen, Franciscus Paridaans, Jan van Lievenoogen
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Abstract
A method and apparatus for the manufacture of lens molds used in the formation of optical contact lenses, the apparatus including a center gate aligned on the central axis of the lens mold cavity for delivery of the melt polymer in an axisymmetrical manner. The methodology produces lens molds of extremely precise dimensions as measured against lens molds produced with side gated technology.
Claims27
An injection molding apparatus for the manufacture of lens molds used for the formation of optical contact lenses, said apparatus comprising:
- (A) a curve insert member and a core member adapted to form in combination a mold cavity having a central axis, said mold cavity configured as a partial sphere with a generally planar annular flange extending from said partial sphere, said core member comprising a center gate aligned on said central axis and connecting to said mold cavity, and
- (B) means to inject liquid polymer through said center gate along said central axis and into said mold cavity.
An apparatus for use in an injection molding device for the manufacture of lens molds used for the formation of optical contact lenses, said apparatus comprising:
- (A) a curve insert member and a core member adapted to form in combination a mold cavity having a central axis, said mold cavity configured as a partial sphere with a generally planar annular flange extending from said partial sphere, said core member comprising a center gate aligned on said central axis, and
- (B) means to inject liquid polymer through said center gate along said central axis and into said mold cavity.
A method of manufacturing a lens mold for producing optical contact lenses, the method comprising the steps of providing an injection molding apparatus capable of delivering liquid polymer into a mold cavity having a central axis, said mold cavity configured as a partial sphere with a generally planar annular flange extending from said partial sphere, providing a curve insert member and a core member within said injection molding apparatus which in combination form said mold cavity, said core member having a center gate aligned on said central axis, delivering liquid polymer into said mold cavity through said center gate, curing said liquid polymer in said mold cavity to form a lens mold, and removing said lens mold.
A lens mold for use in manufacturing optical contact lenses, said lens mold comprising a flat annular flange extending from a spherical central portion, a critical side, a noncritical side a cured polymer sprue extending from the spherical central portion on the noncritical side, and a centrally located sink mark site on the critical side opposite the sprue, said lens mold having a thickness variation of less than 1 micron at the sink mark site, said lens mold produced by the process comprising the steps of providing an injection molding apparatus capable of delivering liquid polymer into a mold cavity having a central axis, said mold cavity configured as a partial sphere with a generally planar annular flange extending from said partial sphere, providing a curve insert member and a core member within said injection molding apparatus which in combination form said mold cavity, said core member having a center gate aligned on said central axis, delivering liquid polymer into said mold cavity through said center gate, curing said liquid polymer in said mold cavity to form a lens mold, and removing said lens mold.
Dependencies are inferred from the claim text.