Speaker system
CA 2116178 C · Owner: Matsushita Electric Industrial Co. Ltd. · Inventors: Takayama, Satoshi; Honda, Kazuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A speaker system comprises an acoustic tube with one end coupled to the back side of the speaker unit and the other end released to a sound field space through an opening window, and at least one air chamber disposed along the acoustic tube. The cross sectional area of the air chamber is larger than the cross sectional area of the acoustic tube, and the cross sectional area of the opening window is smaller than the cross sectional area of the acoustic tube. Therefore, the air chamber forms an acoustic filter so that the higher resonance frequency components in medium and high frequency region caused in the acoustic tube may not be radiated from the opening window, and formation of peaks …
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 February 22, 1994 and granted April 11, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 22, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 22, 2016.
- 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.