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Expired Canadian patentCanada

Optical disc structure and related method of manufacture

CA 1214872 A · Owner: Optical Disc Corporation · Inventors: Winslow, John S.

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

An optical disc structure including two resilient disc members which are bonded together adjacent their outer peripheries and which include an air channel allowing communication between the chamber formed between the discs and the atmosphere. An information layer is formed on the inner surface of at least one of the members. When the members are spun, a pressure differential is caused tending to push the two members apart, thereby assuring that one member will not contact the information layer formed on the other member and that the two members will not be close enough together to cause optical interference.

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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 December 2, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 2, 2003.
  • 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 19, 1984
GrantedDecember 2, 1986
Term endedDecember 2, 2003
Patent numberCA 1214872 A
Classification (IPC)G11B7/24 +2 more

Timeline

Timeline From CIPO dates

1985198719891991199319951997199920012003Application filedJuly 19, 1984Patent grantedDec 2, 1986Term endedDec 2, 2003

Sources & verification

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