Contrast improvement in liquid crystal light valve projectors
CA 2290686 C · Owner: Barco N.V. · Inventors: Van Den Bossche, Bart; Candry, Patrick; Maximus, Bart
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a light valve image projector with a disposition for improving the contrast of an optical image projected on a screen by that projector. The projector comprises at least one illumination system, at least one field lens, at least one set consisting of a polariser an LCD and an analyser and at least a projection lens and presents at least , one optical axis which includes an angle .alpha. with the optical axis of the projection lenses. The invention consists in positioning the analyser (25) so that it includes an angle larger than .alpha. with the LCD at least for the , light rays that pass through the contrast limiting area of the LCD. The invention …
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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 May 20, 1998 and granted December 23, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 20, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 20, 2020.
- 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.