Device for optic, preferably visual determination of a certain plane
CA 1110059 A · Owner: Bergkvist, Lars A. · Inventors: Bergkvist, Lars A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A device for visually determining a plane. When visually viewing the device which is preferably stationary information is received whether or not one is in the plane defined by the device. Information also is received on how to move in relation to the device being viewed in order to be in the plane defined by the device. The device comprises two screen units with the first screen forming an angle with the second screen which second screen is located behind the first screen. The first screen has a finer division than the rear screen thereby creating interference patterns when light falls through the screens.
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
- Granted October 6, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 6, 1998.
- 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.