Optical information recording method and recording apparatus
CA 2020243 C · Owner: Ishibashi, Kenzou · Inventors: Kimura, Kunio; Yamada, Noboru; Akahira, Nobuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is directed to a recording apparatus which overwrites an input signal having pulse duration periods and pulse spacing periods to an optical disk by irradiation of a laser beam to form recording marks corresponding to the pulse duration periods. The apparatus includes a detector for detecting a leading edge of the pulse duration period and for producing a start signal thereupon, another detector for detecting a trailing edge of the pulse duration period and for producing a stop signal thereupon, a pattern setting circuit for setting a predetermined basic pattern, and a pattern generator for generating the basic pattern from its beginning in response to the start signal …
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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 June 29, 1990 and granted December 13, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 29, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 29, 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.