Video display apparatus with kinescope spot burn protection circuit
CA 2039774 C · Owner: Gurley, Thomas David · Inventors: Gurley, Thomas David; Wignot, Leroy Samuel
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A television receiver includes a kinescope spot burn protection circuit comprising a capacitor coupled between a source of blanking signal and a control grid of the kinescope for applying negative grid cut-off bias to the kinescope in response to the blanking signal. The amplifier is of the cascode type having a minimum output voltage for peak white levels of a video signal applied to the cathode. The protection circuit includes a potential divider for biasing the kinescope at a positive voltage level related to the minimum output voltage of the amplifier during normal operation of the receiver to maximize the brightness of displayed images. The protection circuit also includes a breakdown …
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 April 4, 1991 and granted October 17, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 4, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 4, 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.