Resin ophthalmic lenses having a prismatic segment
CA 1113755 A · Owner: Signet Optical Corporation · Inventors: Campbell, Charles D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cast resin ophthalmic lens comprises a homogeneous body defined of cured optical casting resin. The body has a cast optically finished front surface composed of a major surface portion and a minor surface portion. The minor surface portion defines in the front surface in a selected, localized area thereof, a lens segment having a predetermined prismatic optical effect. The major surface portion is a portion of a surface of revolution having a first axis of symmetry and having an effective center of curvature therealong. The minor surface portion is a portion of a surface of revolution having a second axis of symmetry. The first and second axes of symmetry intersect if at all, at a …
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 December 8, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 8, 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.