Optical filter tuning apparatus and an optical filtering method
CA 2047710 C · Owner: Preston, Keith R. · Inventors: Preston, Keith R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical filter tuning apparatus and filtering method which uses an optical filter (8) that reflects light of a predetermined wavelength which is dependent on the position of incidence (16) of the light on the filter (8) and a retroreflector (32) moveable, with respect to the filter (8) and which reflects light from an optical source (4) to the position of incidence (16) and reflects light of the predetermined wavelength from the filter (8) to an optical receiver (6).
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 January 12, 1990 and granted December 9, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 12, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 12, 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.