Manufacturing of positive power ophthalmic lenses
US6390621B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 2000 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | May 30, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29D11/00432
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Multifocal ophthalmic lenses may be manufactured by either injection molding and casting methodologies. The use of two opposed tools (mold faces) with relatively centered faces, but with significantly differing diameters can be used to provide multifocal ophthalmic lenses. The process is surprisingly capable of providing multifocal lenses with good control of the thickness of the lenses, with relatively thin center thicknesses (e.g., less than 4.7 mm, or less than 3.5 mm) and relatively thin edge thicknesses (e.g., 0.5 to 2.5 or to 2.0 mm). The tool faces (the molds for the front and rear surfaces) may be readily replaced within the mold to enable manufacture of a wide range of lens prescriptions with minimum down time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.