Methods for controlling and enhancing the quality of base materials employed for the production of semi-finished ophthalmic lenses
US8066920B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2009 |
| Grant date | Nov 29, 2011 |
| Priority date | — |
| Expiry date | Dec 12, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/808
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Optical qualities of a production lot of base material used in the fabrication of semi-finished lenses may be accurately determined by employing chipper plate samples produced from the base material in accordance with aspects of the present invention. In various implementations of the present invention, the chipper plates samples may be fabricated by subjecting base material to an extended cycle time and temperature profile using a mold having cavities of different thicknesses. The resulting chipper plates provide an improved indication of the color of semi-finished lenses molded from the production lot as well as an improved indication of resin stabilizer defects that may be utilized during a pelletizing process to control and enhance the quality of a production lot. Furthermore, the chipper plates may be provided by suppliers as samples of a production lot to enable customers to base purchasing decisions on a reliable and accurate measure of optical properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.