Indefiniteness – Patent Claims Must “Inform Those Skilled in the Art With Reasonable Certainty” About the Scope of the Invention

In Nautilus, Inc. v. Biosig Instruments, Inc., the Supreme Court reversed the Federal Circuit’s holding that claims directed to a heart rate monitor were sufficiently definite to avoid invalidation and remanded the case to the Federal Circuit.  For a copy of the opinion, click here. The patent claims at issue concerned a heart monitor that includes a cylindrical bar with a display device and two electrodes on each half of the bar which are mounted “in spaced relationship with each other.”  The issue in the case was whether the phrase “in spaced relationship with each other” rendered the claims indefinite.  The district court said “yes,” the Federal Circuit said “no,” and the Supreme Court said the Federal Circuit applied the wrong standard and remanded the case.

 It’s hard to know whether this decision has any real substance to it. The Supreme Court took issue with the standard that the Federal Circuit uses to decide indefiniteness issues.  According to the Federal Circuit, patent claims are indefinite only if they are “insolubly ambiguous” or “not amenable to construction.”  Notably, the district court did construe the claims, but held that the construction did not resolve the imprecision in the claims, and therefore, that they were indefinite. The Supreme Court held that the Federal Circuit standard is improper, and that patent claims are indefinite if they fail to inform those skilled in the art about the scope of the invention with “reasonable certainty.”

 The Supreme Court noted that in some cases the Federal Circuit describes the “insolubly ambiguous” standard in a way that appears to be consistent with the “reasonable certainty” standard.  In addition, the Supreme Court did not decide whether the patent claims at issue in the Nautilus case were indefinite under the “reasonable certainty” standard.  Accused infringers seeking to invalidate patent claims will most likely characterize Nautilus as loosening the standards for indefiniteness and making it easier to invalidate claims. However, at this point, it is not really clear if the Supreme Court was merely clearing up a linguistic issue or actually signaling that prior indefiniteness decisions from the Federal Circuit were substantively wrong.