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Expired Canadian patentCanada

Bias magnetic field generating apparatus

CA 2033275 C · Owner: Matsushita Electric Industrial Co. Ltd. · Inventors: Kawamura, Ichiro; Imanaka, Ryoichi; Naoki, Goro

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

An apparatus for generating a bias magnetic field to a magneto-optical disk includes a movable magnet which serves to generate a bias magnetic field. A suitable device serves to generate a drive magnetic field to move the magnet. A stopper is engageable with the magnet to stop the magnet at a predetermined position.

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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 December 27, 1990 and granted October 25, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 27, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 27, 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.
FiledDecember 27, 1990
GrantedOctober 25, 1994
Term endedDecember 27, 2010
Patent numberCA 2033275 C
Classification (IPC)G11B13/04 +1 more

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedDec 27, 1990Patent grantedOct 25, 1994Term endedDec 27, 2010

Sources & verification

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