Electron tube cathode
CA 2037675 C · Owner: Watanabe, Keiji · Inventors: Shinjou, Takashi; Sano, Kinjiro; Nakanishi, Hisao
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The life characteristics of an electron tube cathode in the operation at a high current density are enhanced. A metal layer of not more than 2.0 µm thick is formed on a base containing nickel as the main ingredient and a reducing agent such as silicon and magnesium by depositing tungsten by an electron beam under heating in a vacuum. The base is heat treated in a hydrogen atmosphere at 800 to 1,100°C. An emissive material layer containing an alkali earth metal oxide and 0.01 to 25 wt% of a rare earth metal oxide the, alkali earth metal oxide containing at least barium oxide is formed on the metal layer. the life characteristics of the cathode especially during the operation at a high …
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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 6, 1991 and granted September 21, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 6, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 6, 2013.
- 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.