Diffraction grating
CA 2006056 C · Owner: Commonwealth Scientific And Industrial Research Organisation · Inventors: Goodman, Richard Alexander; Lee, Robert Arthur; Jackson, Wayne Kevin
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A diffraction grating of reflective or transmissive lines formed by a regular matrix of pixels each containing a respective curvilinear portion of one or more of said lines, which pixels when illuminated each generate a two-dimensional optical catastrophe image diffraction pattern whereby the total image diffraction pattern of the grating is optically variable but structurally stable. The invention further provides a diffraction grating of reflective or transmissive lines, comprising a multiplicity of diffraction grating regions, which are at least partly separated by a multiplicity of grating free regions, each grating free region having a dimension which is at least large enough to be …
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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 December 19, 1989 and granted July 28, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 19, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 19, 2011.
- 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.