An optical information recording and reproducing device
CA 2088188 C · Owner: Sato, Hideaki · Inventors: Sato, Hideaki; Yoshida, Yoshio; Nakata, Yasuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical information recording and reproducing device is provided. The device includes a light source for emitting a light beam, a first diffraction element for splitting the light beam into at least three diffracted beams, an optical system guiding the diffracted beams to a recording medium and a second, diffraction element including at least one division line and a diffraction surface from which the diffracted beams are diffracted. The diffraction surface is divided into at least two regions by the division line or lines. One of the division lines is at a predetermined angle against the direction of a track on the recording medium, and the regions split each of the diffracted beams into …
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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 January 27, 1993 and granted February 16, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 27, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 27, 2015.
- 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.