Hollow light guide for diffuse light
CA 2200441 C · Owner: Whitehead, Lorne A. · Inventors: Whitehead, Lorne A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An outer prism light guide (48) surrounds a cover (52) which in turn surrounds a light source. Guide (48) is formed of prism light guide wall material having uniform shape in cross sections perpendicular to a first octature symmetry direction (44), with its optical centre line (50) parallel to direction (44). Surfaces of the wall material are substantially in octature relative to direction (44). A surface normal vector (46) at any point on any internal surface of the material is either substantially parallel or substantially perpendicular to a first notional line extending from the point through and perpendicular to optical centre line (50). Cover (52) has cylindrical symmetry …
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 October 27, 1995 and granted July 30, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 27, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 27, 2017.
- 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.