Unclean Patents

55 Pages Posted: 23 Feb 2021 Last revised: 31 Oct 2022

See all articles by Sean B. Seymore

Sean B. Seymore

Vanderbilt University - Law School

Date Written: February 19, 2021


The doctrine of unclean hands is perhaps the most storied affirmative defense in civil cases. It allows a court to dismiss a lawsuit without reaching the merits if the patent owner (patentee) engaged in misconduct related to the claim being asserted. In patent law, the Supreme Court has stated that the doctrine is of “paramount interest” given the nature of the patent bargain between the inventor and the public. Nonetheless, unclean hands has been a relatively dormant defense in patent cases, other than in the specific context of patent procurement at the Patent Office (where it has evolved into the doctrine of inequitable conduct). It has also been mostly limited to cases involving litigation misconduct where the dismissal rendered the patent unenforceable against the accused infringer. Recently, however, the defense was successfully asserted against a patentee for prelitigation business misconduct. This holding raised eyebrows because it resurrected the doctrine and applied it more broadly than prior cases.

Resurrecting unclean hands in patent law makes sense from a normative perspective. Allowing patentees to take advantage of their own misconduct contravenes the public interest, jeopardizes the legitimacy of the courts, and ultimately undermines the integrity of the patent system. But this insight raises three important normative questions: First, what types of misconduct should trigger the defense? Second, what nexus in time, causation, and logical linkage should exist between the alleged misconduct and the patent-in-suit? And third, does resurrecting the doctrine align with current patent policy and other goals of the patent system?

I answer these questions in this Article by offering a new theory of unclean hands in patent law. I argue that misconduct during the acquisition of the patent right (other than at the Patent Office) should render the patent universally unenforceable against any potential defendant-infringer if the defendant-infringer can show a sufficient nexus. After exploring the types of misconduct that would or wouldn’t trigger the doctrine, I describe how the proposed approach aligns with normative justifications for unclean hands and broader goals of the patent system. I also offer a set of principles to limit and guide a court’s discretion in applying the doctrine in patent suits.

Keywords: patents, unclean hands, remedies, disclosure, inequitable conduct, fraud, bad faith, affirmative defenses, court integrity

JEL Classification: O31, O32, O33, O34, O38, O40

Suggested Citation

Seymore, Sean B., Unclean Patents (February 19, 2021). Boston University Law Review, Vol. 102, pp. 1491-1545, Available at SSRN: https://ssrn.com/abstract=3789286

Sean B. Seymore (Contact Author)

Vanderbilt University - Law School ( email )

131 21st Avenue South
Nashville, TN 37203-1181
United States

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