Optical recording medium
CA 2023961 A1 · Owner: Sako, Yoichiro · Inventors: Yamagami, Tamotsu; Sako, Yoichiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical recording medium provided with both a recordable area in which data can be recorded and a read-only area in which data has previously been recorded in an unerasable manner. In the recordable area, a guide groove is previously formed for tracking control, and recording may be performed for example, photomagnetically, along the guide groove. In the read-only area, data is previously recorded by offsetting the groove or a land along the track in accordance with the data. This read-only data may be reproduced by detecting the laser light radiated from an optical pickup and reflected by the medium by a twosegment photodetector.
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 August 24, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 24, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 24, 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.