Method of and an apparatus for testing large area panes for optical quality
CA 2024152 A1 · Owner: Erbeck, Ralf · Inventors: Erbeck, Ralf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of testing large area panes of a transparent material for optical quality, especially automotive windshield uses a light box having a uniformly illuminated wall along which a planar grating is provided. The grating has an area at least equal to that of the windshield which is spaced from that grating. An objective in line with the windshield and the grating forms an image of the grating through the windshield on a plane having a reference grating of much smaller size to form a Moir?-pattern superposition which is picked up by a video camera and subjected to phase shift analysis.
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 August 28, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 28, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 28, 2012.
- 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.