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Expired Canadian patentCanada

Optical interference coatings and lamps using same

CA 2017471 C · Owner: Krisl, Matthew Eric · Inventors: Krisl, Matthew Eric; Bateman, Robert L.

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Optical interference coatings useful on lamps for transmitting visible light radiation at about 90% average from 400-770 nm and for reflecting infrared radiation comprise three spectrally adjacent multiperiod stacks of alternating high and low index of refraction layers. Compared to conventional filters these filters have a greater tolerance to layer thickness variations incurred during manufacture with little or no color shift when viewed at non-normal angles.

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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 24, 1990 and granted October 24, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 24, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 24, 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.
FiledMay 24, 1990
GrantedOctober 24, 2000
Term endedMay 24, 2010
Patent numberCA 2017471 C
Classification (IPC)G02B5/26 +2 more

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedMay 24, 1990Patent grantedOct 24, 2000Term endedMay 24, 2010

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.