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Expired Canadian patentCanada

A directional hearing system

CA 2252447 C · Owner: Cardinal Sound Labs, Inc. · Inventors: Lehr, Michael A.; Widrow, Bernard

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A directional acoustic receiving system is constructed in the form of a necklace including an array of two or more microphones mounted on a housing supported on the chest of a user by a conducting loop encircling the user's neck. Signal processing electronics contained in the same housing receives and combines the microphone signals in such a manner as to provide an amplified output signal which emphasizes sounds of interest arriving in a direction forward of the user. The amplified output signal drives the supporting conducting loop to produce a representative magnetic field. An electroacoustic transducer including a magnetic field pick-up coil for receiving the magnetic field is …

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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 April 17, 1997 and granted September 21, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 17, 2017.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 17, 2019.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 17, 1997
GrantedSeptember 21, 1999
Term endedApril 17, 2017
Patent numberCA 2252447 C
Classification (IPC)H04R25/00 +1 more

Timeline

Timeline From CIPO dates

1998200020022004200620082010201220142016Application filedApril 17, 1997Patent grantedSep 21, 1999Term endedApril 17, 2017

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.