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US 6,162,376 AGranted
Compression molding of optical lenses
AssigneeMead Opthalmics
InventorVandenberg Mead, deceased
Life of this patent
Estimating the term…
Abstract
A lens molding system which uses glass molds to mold polycarbonate blanks. The blanks are preheated, then additionally surface heated, molded, and cooled under pressure.
Claims13
A method of forming a polycarbonate lens, comprising:
- obtaining a polycarbonate blank to be molded into a lens;
- preheating the polycarbonate blank to a specific temperature below a deformation point of the polycarbonate material for a time effective to uniformly heat the polycarbonate material;
- raising a temperature of only outer surfaces of the polycarbonate material to a second higher temperature, but below a glass transition point of the polycarbonate material, to soften the surface of the polycarbonate material;
- preheating top and bottom molds to a third temperature, higher than said second temperature to form preheated molds;
- pressing the heated polycarbonate blank between respective first surfaces of said preheated molds, using a substantially same pressure to press from the bottom as is used to press from the top.
2 more elements
A polycarbonate lens molding apparatus, comprising:
- a first glass mold, having a convex molding surface, and having a second surface facing away from said convex molding surface;
- a second glass mold, having a concave lens molding surface, and having a second surface facing away from said concave molding surface;
- a microgranulated heating medium in contact with said second surfaces of both said first and second molds;
- a spring element, pressing said microgranulated heating medium against said second surfaces and
- a pressure applying device, operating to apply substantially constant pressure to both said first and said second molds, to press a polycarbonate lens between said convex surface and said concave surface.
2 more elements
Dependencies are inferred from the claim text.