Rear-projection screen assembly
CA 2004158 C · Owner: Clausen, Johannes · Inventors: Clausen, Erik; Clausen, Johannes
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A transparent rear-projection screen assembly consists of a rearmost Fresnel lens sheet (7a) an, intermediate screen (7b) having on its front and rear sides parallel vertical rows of convex lenses (9 10) and, having vertical ridges (11) with their tops covered by light-impermeable materials (12), and a foremost screen (7c). To the rear side of the Fresnel lens sheet red green and blue pictures are projected from projectors (1 2, 3). The rear side of the foremost screen has parallel convex lenses (71) the focal points (76) of which are located in the front side of the foremost screen. The front side of the foremost screen (7c) is composed of parallel ridges (72) separated by deep recesses …
Read the whole patent
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 November 29, 1989 and granted December 17, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 29, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 29, 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.