Surface acoustic wave devices
CA 2002179 C · Owner: Vaughan, Richard · Inventors: Vaughan, Richard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A surface acoustic wave transponder in which transducers (14) on the surface of a piezoelectric substrate (10) modify an interrogating signal. The transducers are phase encoded by selectively connecting their finger sets to respective busbars (11, 12) and by displacement relative to their nominal positions. Transducer fingers and track-crossing connections (20) are located sa as to cause cancellation of reflected surface acoustic waves. A marker transducer (15) assists decoding. In the encapsulation of the transponders a cover plate (35) or individual cover plates (24) are attached to the substrate prior to the cutting of individual transponders from 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
- Filed November 3, 1989 and granted May 23, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 3, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 3, 2011.
- 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.