Security marking
CA 2004423 A1 · Owner: Traqson Limited · Inventors: Wallace, Stephen C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A security mark has a photochromic compound covered by a controlled absorbtion layer comprising a saturable absorber. Light of a wavelength serbing to convert the photochromic compound is at low intensity absorbed by the saturable absorber. A photochromic compound converted by UV can thus be sunlight protected. At high intensities the absorbtion of the saturable absorber drops to permit conversion of the photochromic compound
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 December 1, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 1, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 1, 2011.
- 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.