Method for forming plastic optical quality spectacle lenses
CA 2046585 A1 · Owner: Blum, Ronald D. · Inventors: Blum, Ronald D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Plastic multifocal or progressive lenses are formed from preformed lenses (11) with predetermined lens corrections at the optical centers. A preformed lens is placed against a mold (13) such that the surfaces of the preformed lens and the mold form a cavity (14). A resin composition fills the cavity and is curved to form an optical segment (12). The cavity (14) is shaped to correspond to a desired change in curvature such that the correction at the optical center is the same as the predetermined lens correction at the optical center of the preformed lens (11). The preformed lens (11) may be cast with a thin non-prescription carrier layer (16) for the multifocal or progressive region of …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed April 20, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 20, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 20, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.