Magneto-optical disk and method of manufacturing the same
CA 2041680 C · Owner: Ohta, Kenji · Inventors: Takahashi, Akira; Toki, Hirotaka; Murakami, Yoshiteru
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magneto-optical disk has a substrate whereon a recording medium is formed, and a depression is formed on the substrate on the inside of the recording medium of the substrate. A center hub is installed on the depression such that the center hub is substantially level with a protective- resin layer covering the recording medium. On the center hub, a flying head performs CSS (Contact-Start-and-Stop). This configuration of the disk eliminates the occurrence of dust due to abrasion and head crash, and achieves stable CSS. A method of manufacturing the magneto-optical disk is also disclosed wherein the protective-resin layer is formed after installing the center hub on the depression. In this …
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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 2, 1991 and granted June 24, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 2, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 2, 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.