Methods and means for reducing temperature-induced variations in lenses and lens devices
CA 2128328 C · Owner: Plummer, William T. · Inventors: Londono, Carmina; Plummer, William T.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A lens (10) imposed of a single material and having at least one refractive surface (14) on one face and a kinoform (20) on the other face(16). The pure refraction between the surfaces varies dimensionally and in refractive index in response to temperature changes and thereby-changes characteristics such as the back , focal length, of the lens while the kinoform varies differently in response to the same temperature changes. The kinoform power is sufficient to vary the temperature induced characteristic changes of the lens in an opposing sense at a given wavelength and in an amount sufficient to athermalize the optical device. In one embodiment the kinoform power compensates for the …
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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 February 12, 1993 and granted August 31, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 12, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 12, 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.
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.