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Expired Canadian patentCanada

Compatible polymers, and use of same for registering optically readable information

CA 1291335 C · Owner: Rohm G.M.B.H. Chemische Fabrik · Inventors: Terbrack, Ulrich; Siol, Werner

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 invention relates to a method for recording storing, and displaying optically readable information in a medium, with the use of a plastic material which can be modified in an optically differentiable way under the action of thermal energy or a form of energy directly convertible into thermal energy. In the method, a polyblend is employed which is comprised of at least two disparate polymers and which are mutually compatible, and which polyblend has an upper critical solution temperature (UCST), whereby an optically differentiable modification of the information storage medium is brought about by the phase transformation from a compatible polyblend above the UCST to the deblended …

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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 29, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 29, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 4, 1988
GrantedOctober 29, 1991
Term endedOctober 29, 2008
Patent numberCA 1291335 C
Classification (IPC)G11B7/24 +2 more

Timeline

Timeline From CIPO dates

1989199119931995199719992001200320052007Application filedMarch 4, 1988Patent grantedOct 29, 1991Term endedOct 29, 2008

Sources & verification

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