Magnetooptical recording medium and method for manufacturing the same
CA 2027870 C · Owner: Sony Corporation · Inventors: Watanabe, Tetsu; Watanabe, Hidetoshi
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 disclosed which is fabricated by a so-called 2P method wherein a pattern of a guide groove or grooves or signal pits is formed by transfer to a photopolymerizable resin layer formed on a substrate, wherein there are formed on the substrate a high magnetic permeability layer a, photopolymerizable resin layer, an magnetooptical recording layer and a transparent protective plate in this order. By this arrangement, it becomes possible to improve an efficiency of a vertical magnetic field wherein an application of a magnetic field from the transparent protective plate is possible and to form a precise pattern in the magnetooptical recording layer. Moreover it …
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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 October 17, 1990 and granted September 12, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 17, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 17, 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
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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.