Electret microphone
CA 1235790 A · Owner: American Telephone And Telegraph Company · Inventors: Tuah-Poku, Isaac; Paulus, Frank S. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Herein disclosed is an electret microphone comprising an electret diaphragm having a thin metallic layer deposited on one of its major surfaces and a ring-, shaped metal washer bonded to the metallic layer of the diaphragm by means of a lightly metal-filled adhesive. Also disclosed is a method for providing an electrically conductive bond between a thin metallized body of insulating material and a metal ring, and a method for batch processing an array of electret diaphragms.
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 April 26, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 26, 2005.
- 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.