Photoreactive lenses
CA 1306643 C · Owner: Baskerville, Martin W. · Inventors: Brettle, Jack; Oliver, Stephen Nigel; Trundle, Clive
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Photoreactive plastics lenses are disclosed which are coated or impregnated with an adamantane 2-spiro-benzo or naphthopyran and with a blue colouring photochromic benzo- or naphthopyran having a nitrogen containing substituent in the 2-position in the pyran ring. The lenses darken in sunlight and fade rapidly at ambient temperatures in the dark or in white light which does not contain a U.V. component. The combination of the yellow/orange colouring adamantane 2-spiro pyran compound with the purple/blue colouring pyran gives a desired brown/grey colouration in the sunlight-darkened lens-. The invention includes novel blue-colouring pyran compounds in which the nitrogen-containing …
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
- Granted August 25, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 25, 2009.
- 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.