Magneto-optic recording disk and method of reproducing recorded signals
CA 2036890 C · Owner: Ishikawa, Toshio · Inventors: Ohta, Kenji; Nakayama, Junichiro; Ishikawa, Toshio
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magneto-optical disk is provided with a transparent substrate of a disk shape and a multiple layered structure which is formed on the substrate and includes a plurality of transparent dielectric films and magnetic recording films which are alternatively layered. One method of reproducing the magneto-optical disk is enabled, which has the steps of inputting a circularly or elliptically polarized light on the magneto-optical disk and detecting an intensity change of light caused by the magneto-optical disk due to the circular dichroism effect thereof, as a reproduced signal. Another method of reproducing the magneto-optical disk is also enabled which, has the steps of inputting a linearly …
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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 February 22, 1991 and granted February 13, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 22, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 22, 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.