Expired Canadian patentCanada
Acoustic transducer with improved electrode spacing
CA 1294032 C · Owner: Carlson, Elmer V. · Inventors: Madaffari, Peter L.; Carlson, Elmer V.
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An acoustic transducer with an improved electret assembly mounting for providing spacings between the fixed and movable electrodes and having, as one feature the lowering of the undesired capacitance therebetween.
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 January 7, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 7, 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.
FiledSeptember 14, 1987
GrantedJanuary 7, 1992
Term endedJanuary 7, 2009
Patent numberCA 1294032 C
Classification (IPC)H04R19/01 +1 more
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.