Federal Court Re-affirms No File Wrapper Estoppel in Canada, but Rebukes Patent Owner for Taking Inconsistent Position08/08/2016
In Pollard Banknote v Babn Technologies, Justice Locke of the Federal Court recently re-affirmed the conventional view that the prosecution history of a patent or ‘file wrapper’ is irrelevant to claim construction in Canada.1 As a result, the patentee in Pollard was not estopped from arguing for a claim construction that contradicted its previous submissions to the Patent Office during prosecution.2 This resulted in a very different claim construction than would otherwise have been the case.3
The rule against using the file wrapper to construe the claims of a patent was established by the Supreme Court of Canada in Free World Trust (2000), which held that the use of such ‘extrinsic evidence’ would increase uncertainty and undermine the public notice function of the claims.4
In 2013 Justice de Montigny of the Federal Court re-opened the debate in Distrimedic Inc v Dispill, in which he held that: “[a] change in the wording of a claim as a result of an objection from the Patent Office is an objective fact from which an inference may be drawn, and is not the same as representations made to the Patent Office.”5 Justice de Montigny later reaffirmed this principle in his 2015 decision in Eli Lilly v Mylan6, shortly before his elevation to the Federal Court of Appeal.
Although the decision in Pollard suggests a return to a more conventional approach, the Federal Court questioned whether it was time to revisit the rule against file wrapper estoppel in Canada, given that file wrappers are now publicly available online.7
The patentee in Pollard was ultimately unable to overcome the prior art cited during prosecution, having now reversed its position on claim construction. In what appears to be a rebuke to the patentee, the Court stated that “it is breathtaking to see [the patent owner] now attempt not just to take a different position on the construction of claim 1, but also to argue that, by doing so, it does not reintroduce the problem of obviousness in light of the [prior art] that it had previously argued was avoided applying its first position.”8 Justice Locke’s comments serve as a warning that one cannot have their cake and eat it too – if a certain construction was necessary to overcome an objection, abandoning that construction at trial leaves the patentee vulnerable to objections raised during prosecution.
While Justice Locke’s ruling on obviousness was made without reliance on the file wrapper,9 his comments suggest that the Court will not look favourably on a patentee who proposes one construction to overcome an objection during prosecution and subsequently takes the opposite position at trial. Pollard indicates that a patentee is still free to adopt whatever construction it chooses to advance at trial – but a patentee who contradicts itself does so at its own peril.
This article is for information purposes only and does not constitute legal or professional advice.
Authors: Andrew Montague, Christopher Langan (former associates)
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