Perpendicular magnetic recording medium and production method thereof
CA 2017696 C · Owner: Koshikawa, Takao · Inventors: Kiuchi, Katsumi; Suzuki, Fumitake; Koshikawa, Takao
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A perpendicular magnetic recording medium for use on a magnetic recording/reproducing apparatus which has a magnetic head for recording/reproduction includes a substrate, a magnetic recording layer having a perpendicular magnetic anisotropy, and a soft magnetic under layer interposed between the substrate and the magnetic recording layer. The soft magnetic under layer includes a mechanism for for suppressing a motion of domain walls of the soft magnetic under layer at least with respect to an external magnetic field which is smaller than a stray magnetic field in a vicinity of the magnetic head within the magnetic recording/reproducing apparatus.
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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 29, 1990 and granted November 29, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 29, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 29, 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.