Supreme Court Unanimously Strikes Down Federal Circuit's 'Insolubly Ambiguous' Test For Indefiniteness, Requires Claims To Have 'Reasonable Certainty' About Scope Of Invention

On June 2, 2014, the Supreme Court of the United States unanimously struck down the Federal Circuit's test for patent claim indefiniteness, holding that the lower court's "insolubly ambiguous" standard tolerated too much ambiguity in patent claims. Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. ___ (2014). Gibson Dunn, representing Nautilus, Inc. ("Nautilus") as co-counsel, successfully urged the Supreme Court to abrogate the Federal Circuit's standard, making it easier to prove a patent claim invalid for indefiniteness under 35 U.S.C. § 112, ¶ 2.

Prior to the enactment of the America Invents Act of 2011, section 112, paragraph 2 required that the patent specification "conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." 35 U.S.C. § 112, ¶ 2 (2006). In Nautilus, the Court rejected the Federal Circuit's test for meeting § 112, ¶ 2--which required only that the claim be "amenable to construction" and "not insolubly ambiguous"--as too permissive and "lack[ing] the precision § 112, ¶ 2 demands." Id., slip op. at 12. Instead, the Court adopted a "reasonable certainty" standard for definiteness of patent claims: whether "a patent's claims, viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty." Id., slip op. at 11. Below, we review the Nautilus decision in more detail. We are available to discuss further on request.

1. Background

   Biosig Instruments, Inc. ("Biosig") is the assignee of U.S. Patent No. 5,337,753 (the "'753 patent"), issued to Dr. Gregory Lekhtman in 1994. Id., slip op. at 3. The '753 patent is directed to a heart-rate monitor for use during exercise that includes a hollow cylindrical bar that a user grips with both hands, coming into contact with two electrodes: one "live" and one "common." Id., slip op. at 4. Relevant to the appeal, claim 1 contains a limitation specifying that the electrodes must be "mounted . . . in spaced relationship with each other." Id.

   Biosig sued Nautilus for infringement. In the resulting litigation, the parties disputed the meaning of the term "spaced relationship." Biosig argued that "spaced relationship" referred to the distance between the live electrode and the common electrode in each electrode pair. Id., slip op. at 6. Nautilus posited that the "spaced relationship" must be a distance "greater than the...