Optical control device
CA 2021572 C · Owner: Nishimoto, Hiroshi · Inventors: Kawashima, Hisao; Nishimoto, Hiroshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical control device comprises optical waveguides provided on a substrate having an electrooptic effect, a buffer layer provided on the substrate to cover the optical waveguides and control, electrodes provided on the buffer layer for applying a predetermined voltage across the optical waveguides. The optical waveguides has a coupling portion at which, an interval of the optical waveguides is narrowed. In this optical control device, a distortion dispersing structure is provided in the vicinity of the control electrodes to disperse distortion locally accumulated in the vicinity of the control electrodes to the whole area of the substrate uniformly.
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 July 19, 1990 and granted August 16, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 19, 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.