Magnetooptical recording medium and recording/reproduction method for medium
CA 2128964 C · Owner: Canon Kabushiki Kaisha · Inventors: Miyata, Katsumi; Osato, Yoichi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magnetooptical recording medium is constituted by laminating at least a first magnetic layer and a second magnetic layer in an order named on a substrate which has transparency and on which receiving a laser beam is incident. The coercive force of the second magnetic layer is greater than that of the first magnetic layer. The coercive force of the second magnetic layer is greater than o~/2M~2h2 where ~w is a, magnetic wall energy between the first and second magnetic layers, M~2 is a saturation magnetization of the second magnetic layer, and h2 is a film thickness of the second magnetic layer. The coercive force of the first magnetic layer is grater than ~w/2M~1h1 where M~w, is a …
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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 July 27, 1994 and granted November 10, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 27, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 27, 2016.
- 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.