Supreme Court Decides Nautilus, Inc. v. Biosig Instruments, Inc.

Section 112, ¶2 of the Patent Act requires that a patent specification "conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." The Federal Circuit had held that a patent passes this threshold so long as the claim is "amenable to construction," and as construed is not "insolubly ambiguous." On June 2, 2014, the Supreme Court decided Nautilus, Inc. v. Biosig Instruments, Inc., No. 13-369, and unanimously rejected this formulation of the definiteness standard. The Court held that a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.

Respondent Biosig is the assignee of the patent in dispute, which concerns heart-rate monitors used during exercise and claims to improve prior art by eliminating inaccuracy caused by other electrical signals coming from elsewhere in the body. The claim term at issue – "in spaced relationship with each other" – dealt with the spacing between electrodes. Following a claim-construction hearing, the district court granted summary judgment for Nautilus, concluding that the term "spaced relationship" was indefinite under 35 U.S.C. §112, ¶2. The Federal Circuit reversed and remanded, finding that the patent survived indefiniteness review. Under the Federal Circuit's holding, a claim is indefinite "only when it is not amenable to construction or insolubly ambiguous."

Seeking to "ensure that the Federal Circuit's test is at least probative of the essential inquiry," the Supreme Court rejected the Federal Circuit's frequently used formulation and raised the bar for patentees attempting to satisfy the definiteness requirement of Section 112, ¶2. The Court recognized, on the one hand, the "limitations of language" and that patents are addressed to those skilled in the relevant art, not lawyers or the public at large. On the other hand, a patent must be precise enough to afford clear notice of what is claimed to apprise the public of what is still open to them. Reconciling these competing concerns, the Court's articulation of the standard mandates clarity while recognizing that absolute precision is unattainable.

Declining to apply the standard announced in Nautilus, the Court reversed and remanded for consideration under the proper standard whether the relevant claims in the patent are sufficiently definite.

Justice Ginsburg delivered the unanimous opinion of the Court.