Apparatus for recording and reproducing information on and from an optical disk
CA 2014535 C · Owner: Sharp Kabushiki Kaisha · Inventors: Deguchi, Toshihisa; Terashima, Shigeo; Fuji, Hiroshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus for recording and reproducing information on and from an optical disk is disclosed in which at least one optical beam and a reference clock signal are used. The optical disk comprises recording tracks which are divided into a plurality of blocks and concentrically arranged along the radial direction. The apparatus comprises: a block judging unit for judging one of the blocks that the one block is currently impinged by the optical beam; a clock signal generator for generating a plurality of clock signals which are different in frequency from each other; and a clock signal selecting unit for selecting one of the clock signals as the reference clock signal on the, basis of the …
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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 12, 1990 and granted October 25, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 12, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 12, 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.