Tracking method and device for use with an optical recording medium
CA 2177546 C · Owner: Nippon Conlux Co. Ltd. · Inventors: Noda, Kazuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
During recording of data on a recording medium tracking is performed using auxiliary beams to refer to guide tracks as done in the conventional three-beam method. During reproduction of data from the recording medium tracking is performed using a main beam to refer to a data pit recorded in a recording track in accordance with the push-pull method. In addition, there are provided two tracking control circuits based on the three-beam method and push-pull method, and the use of tracking control signals based on the three-beam and push-pull methods that are output from the two circuits is selected via a switch.
Read the whole patent
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 28, 1996 and granted August 24, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 28, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 28, 2018.
- 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.