Method of controlling fluorine doping in soot preforms
CA 2366451 A1 · Owner: Marlatt, Deborah L. · Inventors: Lacy, Claud E.; Marlatt, Deborah L.; Deliso, Evelyn M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for controlling the refractive index achieved using a fluorine dopant gas, wherein CF4 is employed as the dopant gas and the soot preform (12) is , doped using the CF4 for a time and temperature sufficient to result in a decrease in fluorine dopant nearest the surface which is in contact with the CF4 gas. Preform (12) is mounted on handle (11) which is fused to handle (14) and the assembly (20) is heated in a furnace muffle (15). The CF4 flows through furnace muffle (15), as indicated by arrows (17) and preferably , contains a diluent gas such as helium. An optional centerflow gas (16) may be flowed through the centerline hole (18) in several embodiments which consists , of …
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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 March 7, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 7, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 7, 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
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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.