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Expired Canadian patentCanada

Method of monitoring the machining by ion bombardment, of a piezoelectric wafer

CA 1061474 A · Owner: Thomson-Csf · Inventors: Berte, Marc; Desormiere, Bernard

CIPO record

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

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Abstract From the Canadian patent

The present invention relates to the monitoring of the machining of a wafer of piezoelectric material by a beam of charged particles. The monitoring method is performed by measuring and displaying the complex voltage-current relationship produced by the electrical excitation of the wafer using a variable-frequency measuring signal applied to electrodes carried by the wafer.

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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 August 28, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 28, 1996.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedAugust 28, 1979
Term endedAugust 28, 1996
Patent numberCA 1061474 A
Classification (IPC)G01R29/22 +2 more

Timeline

Timeline From CIPO dates

198019821984198619881990199219941996Patent grantedAug 28, 1979Term endedAug 28, 1996

Sources & verification

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