The Imminent Arrival Of File Wrapper Estoppel In Canada

For the best part of 18 years, since the judgment of Justice Ian Binnie in Free World Trust, 2000 SCC 66, it has been well-settled law that there is no file wrapper estoppel in Canada. That's all about to change following Bill C-86, which was introduced on October 29, 2018.

File wrapper estoppel is a term used in the United States to describe the use of the prosecution history as recorded in the file at the Patent Office to constrain the interpretation that may be later placed on patent claims. The applicant is prevented from later claiming, e.g. in a patent dispute, that statements made during the application process meant something different, or "estopped" from presenting a claim construction that contradicts his/her previous submissions to the Patent Office during prosecution.