Applying the Supreme Court’s New Standard of Definiteness

Dow Chemical Co. v. Nova Chemicals Corp.1 Applying the Supreme Court’s New Standard of Definiteness In general terms, the definiteness requirement of 35 U.S.C. §112, ¶2 is satisfied if one of ordinary skill in the art would understand the scope of the claims when read in view of the specification and prosecution history. Before June 2014, challenging a claim as invalid for indefiniteness was generally considered a difficult argument to win except in extreme cases. This is largely because for over 10 years, the U.S. Court of Appeals for the Federal Circuit applied a strict standard, often requiring challengers to show that a claim was so unclear as to be “insolubly ambiguous” and not “amenable to construction.”2 But this standard was revisited last summer when the U.S. Supreme Court decided Nautilus, Inc. v. Biosig Instruments, Inc.3 And in a recent decision, the Federal Circuit unequivocally confirmed that “Nautilus changed the law of indefiniteness.” Section 112, paragraph 2 sets forth the definiteness requirement as follows: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.4 In Nautilus, the U.S. Supreme Court addressed the degree of imprecision tolerated by this statute, balanced against a patentee’s obligation to apprise the public of the scope of the claimed invention. The challenged claims in Nautilus were directed to a heart rate monitor with electrodes mounted “in spaced relationship with each other.” The Supreme Court noted that various arguments and even disagreement among the members of the Federal Circuit panel revealed that this language allows for multiple interpretations reflecting markedly...