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Expired Canadian patentCanada

Optical disk

CA 1309178 C · Owner: Ichinose, Makoto · Inventors: Ichinose, Makoto; Takagi, Yuji; Satoh, Isao

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 optical disk having a control track. The control track is divided into sectors in a manner similarly to a data track to record data and comprises a plurality of sectors. Each sector is composed of a sector identifying portion ID in which address information is recorded and a control field portion CF in which control data is recorded. The control field portion CF has the same format as the sector identifying portion ID. The control data is divided into recording data units in the control field portion CF and recorded. An identification flag is provided for each of the sector identifying portion ID and control field portion CF. The control track is searched …

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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 October 20, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 20, 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.
FiledJuly 14, 1988
GrantedOctober 20, 1992
Term endedOctober 20, 2009
Patent numberCA 1309178 C
Classification (IPC)G11B20/12 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedJuly 14, 1988Patent grantedOct 20, 1992Term endedOct 20, 2009

Sources & verification

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