Cathode for electron tube
CA 2188802 C · Owner: Yamashita, Katsuyuki · Inventors: Yamashita, Katsuyuki; Sakurai, Hiroshi; Hayashida, Yoshiki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cathode for an electron tube formed by coating the base of the cathode for the electron tube With an alkaline-earth metal carbonate containing at least barium as the alkaline-earth metal and thermally decomposing in a vacuum to generate an emitter mainly comprising an alkaline-earth metal oxide wherein a, mixture of two or more kinds of alkaline-earth metal carbonate crystalline particles having different shapes is used as the above mentioned alkaline-earth metal carbonate. Since the present invention can provide a cathode for electron tube having improved both cut-off drift and emission characteristic at the same time, it is useful as a cathode for the electron gun of a CRT, or a cathode …
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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 February 29, 1996 and granted December 11, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 29, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 1, 2018.
- 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.