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Litigation Opinions
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Patents - Overbreadth

. Western Oilfield Equipment Rentals Ltd. v. M-I LLC

In Western Oilfield Equipment Rentals Ltd. v. M-I LLC (Fed CA, 2021) the Federal Court of Appeal considered the patent issue of overbreath in challenging a grant:
[128] There are two ways that a patent claim can fail for overbreadth (or overclaiming): it can be broader than the invention disclosed in the specification, or it can be broader than the invention made by the inventor: Pfizer Canada Inc. v. Canada (Health), 2007 FCA 209, 60 C.P.R. (4th) 81 at para. 115.

[129] The concept of claim invalidity for overbreadth (or overclaiming) arises from the combination of the requirements that a patent specification (i) correctly and fully describe the invention (see subsection 27(3) of the Patent Act), and (ii) include "“claims defining distinctly and in explicit terms the subject-matter of the invention for which an exclusive privilege or property is claimed”" (see subsection 27(4)). One may also consider overclaiming as a natural consequence of the bargain theory of patent law as described in Free World Trust at para. 13: "“[i]n return for disclosure of the invention to the public, the inventor acquires for a limited time the exclusive right to exploit it.”" If a patent claims more than it describes, or more than the inventor has made, it gives the patentee more than the bargain entitles them to. Such a claim violates the bargain and is therefore invalid.

[130] Overbreadth often overlaps with other grounds of invalidity. For example, a claim that is invalid for anticipation because it encompasses embodiments that are described in the prior art may also be considered overbroad for claiming more than the inventor has truly invented. In addition, overbreadth might be considered the other side of the coin of insufficiency. Where a claim is broader than the description, it may fail for overbreadth, but it may also fail because the description does not adequately describe how to put it into practice. Despite this possibility of overlap, overbreadth is a distinct ground of invalidity that must be considered separately.


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Last modified: 04-11-22
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