Waveguide type optical device
CA 1306629 C · Owner: Hitachi, Ltd. · Inventors: Sano, Hirohisa; Imoto, Katsuyuki; Hira, Yasuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a waveguide type of optical device a waveguide layer for propagating light is provided on the front surface of a substrate. A compensation layer having a coefficient of thermal expansion substantially equal to that of the waveguide layer is formed on the rear surface of the substrate. The result is to reduce fluctuations of light propagation characteristics due to thermal stress; also to avoid warping or cracking of the substrate.
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 August 25, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 25, 2009.
- 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.