Wdm optical filter and glass substrate for use in the wdm optical filter
CA 2314841 C · Owner: Hoya Corporation · Inventors: Yanagita, Hiroaki; Hashimoto, Kazuaki; Johnson, Robert W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A glass substrate is for use in a WDM optical filter which has an optical multilayer coated on the glass substrate and is formed by glass which has a composition related to the optical multilayer so as to assure stable multiplexing/demultiplexing operation in the optical filter. The glass includes SiO2 as a glass network-former and has an average linear thermal expansion coefficient between 100 x 10 -7/K and 130 x 10 -7/K within a temperature range between -30 °C and +70 °C. The glass may include TiO2 Al2O3, and R20(R: alkali metal element) in addition to SiO2 and may have a hardness suitable for the optical multilayer.
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 August 2, 2000 and granted December 9, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 2, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 2, 2022.
- 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.