Molds and procedure for producing truncated contact lenses
US4407766A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1981 |
| Grant date | Oct 4, 1983 |
| Priority date | — |
| Expiry date | May 26, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/808
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Truncated contact lenses are produced in a direct casting operation using a mold assembly of a male mold member and a female mold member, both of which have molding surfaces and only one of which is provided with an inwardly flexible continuous rim portion. When vulcanizable or polymerizable constituents are placed in the mold, the two mold members are brought together, the flexible rim is flexed inwardly and the finished lens of the desired shape is obtained. The flexible rim is composed of a circular portion having two ends and a straight line connecting the two ends. This defines a chord and provides the finished lens with the truncation desired. Preferably the lens also has a toric surface and prism ballast to assist in positional stability of the lens on the eye of the wearer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.