NOV Downhole Eurasia Limited v TLL Oil Field Consulting 2014 FC 889 Mosley J
The pigeons are coming home to roost from the SCC’s ill-advised holding in Free World 2000 SCC 66, , that prosecution history is not to be used in claim construction (for my critique of the SCC decision, see here).
The invention at issue in NOV Eurasia v TLL Consulting is a downhole oilwell tool which comprises a valve. The defendant alleged that during patent prosecution the applicant had amended the application to restrict the claims to embodiments which included a transverse valve, and they now sought to assert the patent against the defendants even though the allegedly infringing tool does not have a transverse valve .
If we had a doctrine of prosecution history estoppel, this would be a straightforward matter. If indeed the applicant had given up the scope in question during prosecution, then the patentee would be estopped from reclaiming that scope in litigation, and the patent would be construed accordingly. The claim, and the patent, would remain valid, but the defendant’s tool (assuming it did not in fact contain a transverse valve), would not infringe. This is an eminently fair and sensible result.
But because the SCC in Free World held that prosecution history cannot be considered as a matter of claim construction, the defendant in this case pleaded that the applicant’s statements were made “with the intention of misleading the Patent Office,” and so the entire patent is void pursuant to s 53(1) , which provides that:
A patent is void if any material allegation in the petition of the applicant in respect of the patent is untrue, or if the specification and drawings contain more or less than is necessary for obtaining the end for which they purport to be made, and the omission or addition is wilfully made for the purpose of misleading.
The patentee in this case brought a motion to have the paragraphs pleading s 53 struck. Prothonotary Milczynski granted the motion, but Mosley J reversed, holding, after a review of the case law, that “[i]t remains a live issue whether section 53 of the Patent Act may void an entire patent due to steps taken in the application process” . I think Mosley J is right on this point, but given the low threshold for allowing the pleading to stand I will not review the case law in detail.
The broader point is that the SCC’s Free World holding has created an unpalatable dilemma for the lower courts. If s 53 cannot be used in this manner, then a patentee may be able to narrow the scope of its claim during prosecution to obtain the patent and then try to reclaim that scope in subsequent litigation. On the other hand, if s 53 can be used, then what would have been a battle over claim construction turns into an atomic bomb of patent invalidity. This will increase uncertainty, as opposed to the option of admitting prosecution history in claim construction, because the intent element of s 53 is inherently uncertain. Moreover, to the extent that there is any justification for excluding prosecution history, it is to simplify the claim construction exercise; but to introduce exactly the same evidence under s 53 means that while claim construction is simpler, the litigation as a whole is at least as complex. Indeed, it will be more complex, because the stakes have been raised from scope to validity, ensuring that all the more money will be put into this uncertain issue.
It is not unlikely that in this case the s 53 issue will ultimately become moot, even if it does go to trial. The claims themselves refer to “the valve member being transversely movable,” and the court may well construe the claims to exclude tools without a transverse valve even without the aid of the prosecution history. That will be all the more unfortunate, as parties in future litigation will have to engage the s 53 issue, instead of what could have been a much simpler matter of claim construction. The SCC in Free World feared opening the “Pandora’s box”  of file wrapper estoppel. By refusing to do so, it opened the far more dangerous box of s 53.