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Expired Canadian patentCanada

Gamma correction device

CA 2008690 C · Owner: Takayama, Tsutomu · Inventors: Takayama, Tsutomu

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A gamma correction device comprises a classifying circuit which divides an input video signal into a plurality of level ranges according to a plurality of signal levels; a computing circuit which computes the region of the video signal within each of the level ranges obtained by the classifying circuit; and a gamma correction control circuit which is arranged to have the gamma correction characteristic thereof controlled according to each region computed by the computing circuit, to gamma-correct the input video signal and to output the gamma-corrected video signal.

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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 January 26, 1990 and granted December 27, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 26, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 26, 2012.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 26, 1990
GrantedDecember 27, 1994
Term endedJanuary 26, 2010
Patent numberCA 2008690 C
Classification (IPC)H04N5/20

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedJan 26, 1990Patent grantedDec 27, 1994Term endedJan 26, 2010

Sources & verification

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