Recording and reproduction system
CA 2014698 C · Owner: Canon Kabushiki Kaisha · Inventors: Yoshinaga, Kazuo; Ohnishi, Toshikazu; Oikawa, Katsuya
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A memory medium includes a memory layer of a polymer liquid crystal and a reflection layer disposed on a substrate. A record part having a different refractive index from that of a non-record part is formed in the memory layer so that the record part and the non-record part have a difference in optical thickness of the memory layer. In a reproduction step the memory medium is irradiated with a reproduction beam of coherent light so that the reproduction beam is transmitted through the memory layer, reflected at the reflection layer and re-transmitted through the memory layer, during which the reproduction beam is subjected to interferential diffraction due to the optical thickness …
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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 April 17, 1990 and granted December 6, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 17, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 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
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.