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Expired Canadian patentCanada

Graphics input tablet

CA 1297177 C · Owner: International Business Machines Corporation · Inventors: Pascual, Rafael; Miessler, Milan

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 graphics input tablet has a conductive layer and a resistive layer with contacts (16,17,23,24) arranged one along each edge of the resistive layer. The conductive layer is held at a negative potential relative to the resistive layer so current flows in each contact when localised pressure is applied to a region of the tablet (20) to bring the layers into electrical contact. The currents vary with both position and magnitude of the localised pressure. The position of the pressure is detected from the relative currents in opposed contacts and the magnitude of the pressure is detected from the total current in the contacts. The currents are measured by current sense amplifiers and processed …

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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 March 10, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 10, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 14, 1988
GrantedMarch 10, 1992
Term endedMarch 10, 2009
Patent numberCA 1297177 C
Classification (IPC)G08C21/00 +1 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedApril 14, 1988Patent grantedMarch 10, 1992Term endedMarch 10, 2009

Sources & verification

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