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Expired Canadian patentCanada

Aligned stretched surface recording medium

CA 1314981 C · Owner: Minnesota Mining And Manufacturing Company · Inventors: Mccracken, John A.; Kelley, Barry L.

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

Abstract of the Disclosure, Stretched surface recording disk (SD) 10 comprises an annular support 12 having raised annular ridges 44 and 32 at or near its inside and outside diameters 22 and 30 with a base portion 24 in between the two ridges, and two annular recording medium films 14 and 16 held in radial tension and stretched across the base portion by adhering the film near the inside and outside diameters. The major principal orientation axis of each annular recording medium film 14 and 16 is determined and the SD assembled so that the axes are aligned in the same direction. This aligning results in SD with reduced track anisotropy due to warping of the annular support 12. As a result, …

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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 23, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 23, 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.
FiledMay 29, 1989
GrantedMarch 23, 1993
Term endedMarch 23, 2010
Patent numberCA 1314981 C
Classification (IPC)G11B5/82 +1 more

Timeline

Timeline From CIPO dates

1990199319961999200220052008Application filedMay 29, 1989Patent grantedMarch 23, 1993Term endedMarch 23, 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.