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Expired Canadian patentCanada

Optical readable storage disc

CA 1211559 A · Owner: Koninklijke Philips Electronics N.V. · Inventors: Janssen, Peter J.M.

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

11, ABSTRACT:, An optically readable storage disc comprises a transparent substrate 1 in which a recording layer 2 is deposited which can be modified locally by means of a radiation beam, the recording layer is covered by a cover disc 3 which is secured to the substrate in a gas-tight manner at some distance from the part of the recording layer which is intended for recording, so that a sealed space 4 is enclosed between the substrate 1 and the cover disc 3. The cover disc 3 will be deformed to the greatest extent under the influence of differences between the gas pressure in the sealed space 4 and the barometric pressure because its resistance to deformation is made substantially smaller …

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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 September 16, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 16, 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.
FiledFebruary 2, 1984
GrantedSeptember 16, 1986
Term endedSeptember 16, 2003
Patent numberCA 1211559 A
Classification (IPC)G11B33/14 +1 more

Timeline

Timeline From CIPO dates

1985198719891991199319951997199920012003Application filedFeb 2, 1984Patent grantedSep 16, 1986Term endedSep 16, 2003

Sources & verification

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