Multilayer thin film dielectric bandpass filter
CA 2220291 C · Owner: Jds Fitel Inc. · Inventors: Cushing, David Henry
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A design for producing bandpass filters with passbands that are centered at the same wavelength for each mode of polarization. Filters are of the all-dielectric type that consist of single and multiple cavities of bandpasses. All of the layers are of the Quarter Wave type for ease of manufacture with the possible exception of the last few layers being modified to reduce reflection into a new media. The basic structure of the multi-layer bandpass filter is as follows:, (XY)n(YY)(XX)m(YY)(YX)n where n and m are integers and wherein X is one of a high refractive index layer and a low refractive index layer; and wherein Y is the other of the high, and low refractive index layer X and Y being …
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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 November 5, 1997 and granted July 8, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 5, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 5, 2019.
- 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.