Optical instrument and optical element thereof
CA 2275819 C · Owner: Freeman, Robin John · Inventors: Freeman, Robin John
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical instrument is described in which a diffractive element (25) is located at a focal or image plane (3) of the instrument and the diffractive element (25) is effective to produce an array (6) of a plurality of exit pupils at a viewing position for the instrument and thereby to form an enlarged exit pupil for the instrument. The diffractive element is formed to provide a plurality greater than two of optical diffractive gratings each being disposed angularly relative to others of the plurality of optical diffractive gratings. (Figure 3)
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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 21, 1999 and granted April 19, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 21, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 21, 2021.
- 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.