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Expired Canadian patentCanada

Lcd addressing system

CA 2060735 C · Owner: Clifton, Benjamin Robert · Inventors: Scheffer, Terry James; Clifton, Benjamin Robert

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A method and apparatus for addressing faster responding liquid crystal panels (LCDs) so that video rate high information content LCDs having time constants on the order of 50ms or less, are perceived as having brighter bright states and darker dark states by limiting peak voltage levels across the pixels. A first set of LCD electrodes are continuously driven with signals each comprising a train of pulses that: are periodic in time; have a common period T; are independent of the information to be displayed; and are preferably orthonormal. A plurality of column signals are generated from the collective information state of the pixels defined by the overlap with a second electrode pattern. …

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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 6, 1992 and granted April 13, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 6, 2012.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 6, 2014.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 6, 1992
GrantedApril 13, 1999
Term endedFebruary 6, 2012
Patent numberCA 2060735 C
Classification (IPC)G09G3/36

Timeline

Timeline From CIPO dates

1993199519971999200120032005200720092011Application filedFeb 6, 1992Patent grantedApril 13, 1999Term endedFeb 6, 2012

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.