Thermoplastic lens blocking material
US5885700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1997 |
| Grant date | Mar 23, 1999 |
| Priority date | — |
| Expiry date | Mar 17, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31587
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The present invention provides thermoplastic ophthalmic lens blocking compositions that have many advantages over traditional metal alloy materials. Preferred compositions comprise a blend of (i) a hydrocarbon resin, preferably an aromatic hydrocarbon resin; (ii) a side chain crystallizable hydrocarbon polymer or copolymer; and (iii) optionally an modifier or mixture of modifiers, preferably straight chain alcohols. The composition may also comprise one or more modifiers, fillers or heat absorbing materials. In one embodiment, the composition is used to fill the cavity between a preformed lens block and a lens. In another embodiment the composition is used to form a lens block. Methods of holding a lens blank are taught. Tapes that provide a receptive surface against which the composition may be adhered are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.