Information recording and reproducing device
CA 2044426 C · Owner: Terashima, Shigeo · Inventors: Fuji, Hiroshi; Iwaki, Takashi; Yamaguchi, Takeshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An information recording and reproducing device uses a disk-shaped recording medium which is rotated at a constant angular velocity. The recording medium is divided into a plurality ring-shaped zones of concentric circles. In a recording area of the recording medium the, number of sectors per track is uniform in each zone and the number of sectors increases from an innermost zone towards an outermost zone. Each sector has a header area wherein header information including address information is recorded and a data area wherein data is recorded. In this device, data is recorded and reproduced in the data area in accordance with clock signals whose frequencies increase from the innermost zone …
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 June 12, 1991 and granted July 16, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 12, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 12, 2013.
- 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.