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Expired Canadian patentCanada

Disc shaped recording medium and recording/reproducing apparatus therefor

CA 2049706 C · Owner: Sony Corporation · Inventors: Tsurushima, Katsuaki; Ohga, Norio; Yoshida, Tadao

CIPO record

Overview

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

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Abstract From the Canadian patent

A disc-shaped recording medium and a recording/reproducing apparatus employing the disc-shaped recording medium as a recording medium, are disclosed. The recording medium has a diameter of not more than 80 mm, and a recording track is formed on the recording medium with a track pitch of approximately 1 .6m. An information in excess of 130 Mbytes is recorded in a data compressed state on the recording track and the recording medium is rotationally driven at a constant linear velocity for recording and optically reproducing the information. The recording/reproducing apparatus employing the disc-shaped recording medium as a recording medium includes a buffer memory between a data compressing …

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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 August 22, 1991 and granted November 14, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 22, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 22, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 22, 1991
GrantedNovember 14, 2000
Term endedAugust 22, 2011
Patent numberCA 2049706 C
Classification (IPC)G11B7/00 +2 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedAug 22, 1991Patent grantedNov 14, 2000Term endedAug 22, 2011

Sources & verification

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