Section 53.1 of the Patent Act took effect in 2019. It was designed to reverse the 2000 decision of the Supreme Court in Free World Trust v Electro Santé Inc [2000] 2 SCR 1024 and allow what transpires in the Canadian Patent Office during the processing of a patent application — its “prosecution history” — potentially to affect the scope of the patent eventually granted. The section could have just provided that a patent’s prosecution history is relevant and admissible to aid in the construction of a patent claim or specification. Instead its drafting is linked to court procedure and, if interpreted literally, produces worse consequences than those it sought to remedy. The paper shows how section 53.1 may be legitimately interpreted to avoid such consequences and achieve the provision’s intended purpose.

Prof David Vaver is a Professor of Intellectual Property Law at Osgoode Hall Law School and Emeritus Professor of Intellectual Property & Information Technology Law at University of Oxford. This is an abstract from Prof Vaver's recently published article which will also appear in the Intellectual Property Journal. You can read the full article either on Osgoode Digital Commons or SSRN.