Yesterday, the Federal Circuit decided Biosig Instruments v. Nautilus, Inc. on remand from the U.S. Supreme Court. Applying the Supreme Court’s new “reasonable certainty” standard for indefiniteness, the Federal Circuit again found the claims not indefinite.

Biosig sued Nautilus for infringing U.S. Patent No. 5,337,753 (the “’753 patent”), which is directed to a heart rate monitor for exercising.  On summary judgment, the District Court found the ’753 patent invalid as indefinite. The Federal Circuit reversed under its then- standing test – that a claim was indefinite only when it was “not amenable to construction” or “insolubly ambiguous.”  Biosig Instruments v. Nautilus, Inc., 715 F.3d 891, 898 (Fed. Cir. 2005).

The claim term asserted to be indefinite was “spaced relationship,” which the Federal Circuit described as the distance on a user’s body between the live and common electrodes that sense heart rate. The U.S. Supreme Court rejected the “insolubly ambiguous” test,  vacating and remanding the decision. The Supreme Court held that the proper test for indefiniteness is when “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.”  Nautilus, Inc. v. Biosig Instruments, Inc. 134 S.Ct.  2120, 2124 (2014).

Applying the new standard, the Federal Circuit concluded that Biosig’s claims “inform those skilled in the art with reasonable certainty about the scope of the invention.” The Federal Circuit relied on only intrinsic evidence (the specification, claims, figures, and prosecution history), reviewing the claim scope determination de novo under Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S.Ct. 831, 842 (2015).

In analyzing whether “spaced relationship” was indefinite under the new standard, the Federal Circuit noted the judiciary commonly applied “reasonable certainty” in a wide   variety of cases.  The Court then looked to prior case law where context had determined whether terms of degree and functional language were definite.  The Court noted that terms of degree had been definite where appropriate standards for measurement were either taught by the specification or within the knowledge of those skilled in the art prior to the invention. Embodiments in the specification also had rendered claims definite by teaching “objective boundaries.” However, a term of degree had been indefinite when it depended on the “unpredictable vagaries of any one person’s opinion.”

Although the ‘753 patent did not define “spaced relationship” with actual parameters, the Federal Circuit found the claim language, specification, figures and prosecution history sufficiently defined the bounds of the “spaced relationship” between the live and common electrodes. This intrinsic evidence taught that the distance between the live electrode and the common electrode could not be greater than the width of a user’s hand, and could not be so small as to effectively be only one detection point (effectively merging the separate electrodes into one), in addition to teaching ways to measure the appropriate distance.

The Federal Circuit therefore concluded that the claimed “spaced relationship” informed those skilled in the art of the scope of the invention with reasonable certainty, in compliance with 35 U.S.C. § 112, ¶ 2.  Thus, despite the change in law, the Court came to the same conclusion it had made under the “insolubly ambiguous” standard applied prior to the remand from the Supreme Court.  The Federal Circuit accordingly reversed the finding of indefiniteness and remanded the case back to the district court.