Magnetic recording medium and information recording-reproduction method using the same
CA 2048868 C · Owner: Ohta, Kenji · Inventors: Hirokane, Junji; Takahashi, Akira; Murakami, Yoshiteru
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magnetic recording medium has a recording layer made up of a ferrimagnetic material whose compensation temperature is substantially within room temperatures and an information, recording-reproduction method uses the magnetic recording medium. During recording, while a light beam is projected on the recording layer so as to raise the temperature of a recording portion, information is recorded by applying a signal magnetic field from a magnetic head. During reproduction while, a light beam is projected on a reproducing portion of the recording layer so as to raise the temperature thereof information is reproduced by detecting leakage flux from the reproducing portion by the magnetic head. …
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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 9, 1991 and granted November 9, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 9, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 9, 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.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.