Method and apparatus for improving vertical sharpness of picture tubes
CA 2089357 C · Owner: Hackett, Andrew Denys · Inventors: Bolender, Nadine; Boie, Werner; Hackett, Andrew Denys
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Large format TV tubes must produce a high peak brightness in order to be acceptable to the user. This results in a large beam current in bright areas of the picture and in a subsequent defocussing of the resulting spot on the display and in a loss of the sharpness of vertical and horizontal transitions. The apparent sharpness of a vertical transition is gained by modifying the deflection of the TV receiver such that at vertical transitions, the line on , the bright side of the transition is deflected away from the transition region. Advantageously the amount of vertical scan modulation corresponds to a multi-level control signal and depends on the grey levels of the transition.
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 September 6, 1991 and granted June 12, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 6, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 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.
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.