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Expired Canadian patentCanada

Apparatus and method for providing a gray scale in liquid crystal flat panel displays

CA 1322257 C · Owner: Honeywell Inc. · Inventors: Sarma, Kalluri R.

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Abstract From the Canadian patent

A liquid crystal display is described that includes gray scale capability. Each pixel of the display is subdivided into a plurality of subpixels. Each subpixel has coupled thereto a thin film transistor, the thin film transistor coupled to the effective subpixel capacitor. The liquid crystal material is contained between the effective capacitor plates. The voltage applied to the effective capacitor resulting from current flowing through the thin film transistor controls the optical activity of the subpixel. By controlling parameters associated with the thin transistor and by controlling the voltage applied to the pixel (and the subpixel thin film transistors), the optical properties of the …

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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

  • Granted September 14, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 14, 2010.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 10, 1988
GrantedSeptember 14, 1993
Term endedSeptember 14, 2010
Patent numberCA 1322257 C
Classification (IPC)G09G3/36 +2 more

Timeline

Timeline From CIPO dates

19891992199519982001200420072010Application filedNov 10, 1988Patent grantedSep 14, 1993Term endedSep 14, 2010

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