Magneto-optical recording medium
CA 2017300 C · Owner: Tanaka, Hiroshi · Inventors: Shimizu, Teruhisa; Takayama, Shinji; Tanaka, Hiroshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magneto-optical recording medium has a first magnetic layer laminated on a second magnetic layer the first, magnetic layer, of (Nd, Pr)-transition-metal amorphous alloy systems, having high magneto-optical effect at short wavelengths but low perpendicular anisotropy and the second, magnetic layer, of (Tb Dy)-transition-metal amorphous alloy, systems having low magneto-optical effect at short wavelengths but low perpendicular anisotropy. By exerting magnetic exchange coupling between these two layers on the said first layer to induce strong perpendicular anisotropy in it, a perpendicular magnetized magneto-optical recording medium is obtained that has overall high magneto-optical effect, …
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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 May 22, 1990 and granted May 17, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 22, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 22, 2012.
- 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.