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Expired Canadian patentCanada

Magnification compensation apparatus

CA 1308203 C · Owner: Herriot, Glen A. · Inventors: Shaw, David A.; Herriot, Glen A.

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 an apparatus for generating a magnification compensation signal for use in a scanning electron microscope. The apparatus includes an electron beam generator that generates a beam at a predetermined energy level in accordance with a beam energy signal. The apparatus allows for refocussing by varying the beam energy signal about a nominal value corresponding to the predetermined energy level. The apparatus also provides a magnification compensator producing a magnification compensation signal that varies in accordance with the variation of the beam energy signal from the predetermined energy level.

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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 29, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 29, 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.
FiledJune 1, 1989
GrantedSeptember 29, 1992
Term endedSeptember 29, 2009
Patent numberCA 1308203 C
Classification (IPC)H01J37/21 +1 more

Timeline

Timeline From CIPO dates

1990199219941996199820002002200420062008Application filedJune 1, 1989Patent grantedSep 29, 1992Term endedSep 29, 2009

Sources & verification

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