Rugate filter having suppressed harmonics
CA 2122932 C · Owner: Hughes Aircraft Company · Inventors: Rahmlow, Thomas D. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A rugate filter (10) having suppressed harmonics includes a layer (18) of material disposed on a surface (14) of an optical substrate (12) having an index of refraction versus thickness profile that is the superposition of a principle sinusoid and a secondary sinusoid. The secondary sinusoid being superimposed about -90 degrees out of phase with the principle sinusoid.
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 May 5, 1994 and granted January 6, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 5, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 5, 2016.
- 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.