Optical disc device
CA 2255390 C · Owner: Nomura, Masaru · Inventors: Nomura, Masaru
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A controller instructs a spindle motor to start rotating, and instructs a servo control section to start a focus servo control. When a light beam crosses information tracks on an optical disc with a rotation of the optical disc, an amplitude indicating signal generating section detects changes in the amplitude of a readout signal output from an optical pickup. A disc type identifying section identifies types of optical discs having different track pitches of the information tracks in starting the rotation of each optical disc based on the peak value and bottom value or the amplitude of the readout signal. Consequently the, types of optical discs having different information recording …
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 December 9, 1998 and granted August 14, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 9, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 9, 2020.
- 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.