Method for producing vitreous optical elements by injection molding with pressure application
AssigneeFuji Photo Optical Co., Ltd.
InventorShin-ya Okada
Life of this patent
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Abstract
Method and apparatus for producing vitreous optical elements by injection molding, which essentially includes the stages of: melting down a glass material into a molten state in a viscosity at or lower than a working point of the glass material; injecting molten glass under pressure into a mold cavity defined between transfer surfaces of relatively movable mold members of a mold assembly unit in communication with a sprue connecting the mold cavity with an injection port on the outer side of the mold assembly unit; and applying a predetermined pressure on the glass material in the mold cavity while cooling the mold assembly unit down to a temperature in the vicinity of yielding point of the glass material.
Claims4
A method for-producing vitreous optical elements by injection molding, comprising:
- a melting stage for melting down a glass material into molten state in a viscosity at a working point or lower than a viscosity at a working point of said glass material;
- an injection stage for injecting molten glass through a sprue into a mold cavity of a split mold assembly having upper and lower mold members in a closed position;
- and
- a pressing stage for applying a predetermined pressure on the glass material in said mold cavity by further moving one of said mold members toward the other mold member from said closed position in a cooling stage following said injection stage at a time point w hen glass material in said sprue has solidified and while said mold assembly is being cooled down to a temperature in the vicinity of a yield point of said glass material.
Dependencies are inferred from the claim text.