Electret capacitor microphone
CA 2315417 A1 · Owner: Une, Hiroshi · Inventors: Une, Hiroshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An electret capacitor microphone is constituted by a surface conductive diaphragm, a fixed electrode provided opposite to the diaphragm at a regular interval and a solid state device for converting, into an electric signal a, voice given to the diaphragm with a change in an electrostatic capacity between the diaphragm and the fixed electrode. The microphone comprises a dielectric casing having a bottomed hollow portion for accommodating the diaphragm, the fixed electrode and the solid state device. Since the casing itself is dielectric it does not deed to, accommodate a special dielectric or a board for the solid state device but can be directly provided in the hollow portion. Therefore, …
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 August 10, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 10, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 10, 2022.
- 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.