Method and device for recording data in an optical memory card
CA 2242195 C · Owner: Onodera, Akira · Inventors: Onodera, Akira; Kimura, Yasuyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method and a device for recording data in an optical memory card which facilitate judgment between an unrecorded region and a recorded region in the optical memory card and which prevent double writing. Record pits are formed so that data to be recorded on the optical memory card is recorded in the same way as when recorded in the MFM-RZ modulation system. Data that was recorded in the NRZI-RZ modulation system is reproduced and the modified to record in the MFM-RZ modulation system. This method forms the record pits at least every two recording intervals or less in the recorded region in the optical memory card, making it possible to fudge the unrecorded region of the optical memory card …
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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 November 10, 1997 and granted November 7, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 10, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 10, 2019.
- 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.