Method for the manufacture of a light-polarizing polyvinylene sheet
CA 2249898 A1 · Owner: Polaroid Corporation · Inventors: Kadaba, Narendra S.; Shah, Lori P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is provided for the manufacture of a polyvinylene-based light polarizer (cf. a "K Sheet"-type polarizer). In one embodiment the, polyvinylene chromophore of said polarizer is produced by the acid catalyzed dehydration of an oriented polymeric starting material the acid catalyst being, introduced in the method as a bonding agent used to secure the starting materialto a carrier web (or other supporting substrate). Advantages of the method include reduced frequency of "streaking" and "mottling"; good processing speed; and the ability to use a low acid concentration resulting in a, correspondingly low-corrosion processing environment.
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 October 9, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 9, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 9, 2020.
- 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.