Method of casting a contact lens
First Claim
Patent Images
1. A method of cast moulding a contact lens comprising the steps of:
- placing a monomer in a mould having a mould cavity between relatively movable male and female mould surfaces, either one of the mould surfaces having a rigid shoulder integral therewith for forming a peripheral seal between the two mould surfaces to close the cavity, at least one of the mould surfaces being flexible under a loading pressure;
closing said mould cavity with monomer filling the cavity;
placing the mould in a pressure vessel;
applying a superatmospheric pressure so that said loading pressure acts on the mould surfaces and forms a pressurized seal around said rigid shoulder; and
curing the monomer whereby said loading pressure causes deflection of one of the mould surfaces to maintain the surfaces in contact with the lens as the monomer shrinks during polymerisation.
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Accused Products
Abstract
A mould for cast moulding a contact lens comprises a first cup member having a male mould surface and a second cup member with a female mould surface. The two cup members form a piston and cylinder and are used in a pressure vessel so as to apply loading pressure to deflect the mould surfaces to maintain the surfaces in contact with a lens being cast. The mould is opened with the mould surface facing upwardly. Hydrating fluid is added to the first cup member and a cover sealed to the top of the first cup member.
191 Citations
14 Claims
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1. A method of cast moulding a contact lens comprising the steps of:
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placing a monomer in a mould having a mould cavity between relatively movable male and female mould surfaces, either one of the mould surfaces having a rigid shoulder integral therewith for forming a peripheral seal between the two mould surfaces to close the cavity, at least one of the mould surfaces being flexible under a loading pressure; closing said mould cavity with monomer filling the cavity; placing the mould in a pressure vessel; applying a superatmospheric pressure so that said loading pressure acts on the mould surfaces and forms a pressurized seal around said rigid shoulder; and curing the monomer whereby said loading pressure causes deflection of one of the mould surfaces to maintain the surfaces in contact with the lens as the monomer shrinks during polymerisation. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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3. A method of cast moulding a contact lens comprising the steps of:
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polymerising a monomer in a mould cavity between a male mould surface in a first mould part and a female mould surface in a second mould part; opening the mould to expose the cast lens while supported on said male mould surface; and sealing the lens in a package by sealing a cover member onto said first mould part.
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Specification