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US Supreme Court to Review Indefiniteness Standard under Section 112 of the Patent Act

White & Case Technology Newsflash

On January 10, 2014, the Supreme Court agreed to review the Federal Circuit's standard for determining whether a patent claim is indefinite in Nautilus, Inc. v. Biosig Instruments, Inc. (S. Ct. No. 2013-0369), a case that could have major implications for future patent litigants. If the Supreme Court rejects the Federal Circuit's stringent standard for proving indefiniteness, many patents will be more vulnerable to early invalidity challenges at the claim construction stage. The decision could also substantially change the way in which patent claim terms and specifications are drafted.

Under Section 112, ¶ 2, of the Patent Act, every patent specification must conclude with "one or more claims particularly pointing out and distinctly claiming the subject matter" which the inventor regards as the invention.[1] Patent claims must be "sufficiently definite to inform the public of the bounds of the protected invention."[2] Under the Federal Circuit's current standard, claim language is indefinite, and the claim is therefore invalid, only when it is "not amenable to construction" or is "insolubly ambiguous."[3]

The claims at issue in Nautilus are directed to heart rate monitors for use with exercise equipment. The claims describe a hand grip bar with two electrodes mounted in a "spaced relationship" with each other. This design allegedly improves upon prior art designs by canceling out the "noise" created by the movement of the body's skeletal muscles, which interferes with the detection of electrical signals generated by the heart.

The patent holder, Biosig, sued Nautilus for patent infringement. After claim construction, the district court granted Nautilus's motion for summary judgment of invalidity, holding that the claim term "spaced relationship" was indefinite.[4] Although the district court was able to construe the term to mean "a defined relationship" between the two electrodes, the court found that the term, as construed, was insolubly ambiguous because the claim term did not tell one "what precisely the space should be" or provide any parameters for determining the spacing.[5]

The Federal Circuit reversed, holding that the disputed term was amenable to construction and not insolubly ambiguous.[6] The Federal Circuit found the claim language, specification and the figures illustrating the "spaced relationship" provided sufficient guidance to skilled artisans as to the bounds of the claim term.[7] Specifically, the term has inherent limitations: the spacing could not be greater than the width of a user's hand, nor could it be so "infinitesimally small" as to effectively merge the two electrodes at one point.[8] The patent also describes this spacing in functional terms (i.e., it substantially removes signals that interfere with the heart's electrical signals), and this function could be optimized using commonly known methods.[9]

In its petition to the Supreme Court, Nautilus presented two questions:

1. Does the Federal Circuit's acceptance of ambiguous patent claims with multiple reasonable interpretations—so long as the ambiguity is not "insoluble" by a court—defeat the statutory requirement of particular and distinct patent claiming?

2. Does the presumption of validity dilute the requirement of particular and distinct patent claiming?

Nautilus argues that the Federal Circuit's stringent standard defeats the public notice function of patent claims by allowing some ambiguity, so long as the term is not "insolubly ambiguous." This, Nautilus asserts, is contrary to the statutory requirement that inventors "particularly point out" and "distinctly claim"[10] their inventions, and conflicts with over a century of Supreme Court precedent requiring greater clarity. According to Nautilus, the standard essentially allows vague claims to issue, only to be cured years later during claim construction. For its part, Biosig argues that the statutory presumption of validity mandates the more stringent "insolubly ambiguous" standard.

The Supreme Court showed an interest in addressing this question in 2011 in Applera, but declined to review that case. The Court's decision to take up the question now, in a case where the "insolubly ambiguous" standard is front and center, signals a possible shift in the law of indefiniteness. The Court could decide that ambiguous claim terms are inherently indefinite, or that any such ambiguity should be construed against the patentee. Or the Court could affirm the current standard. If the Court sides with Nautilus, weak patents with ambiguous claim terms may be easier to defeat early on in litigation, possibly before substantial discovery is undertaken. This could be a particularly valuable weapon in defending against so-called "troll" litigation.


[1] - 35 U.S.C. § 112 ¶ 2. This language is now found in § 112(b), which is applicable to patents filed after September 16, 2012.
[2] - Halliburton Energy Servs., Inc. v. M-I LLC, 514 F.3d 1244, 1249 (Fed. Cir. 2008).
[3] - Id. at 1250.
[4] - Biosig Instruments, Inc. v. Nautilus, Inc., No 10-cv-7722 (S.D.N.Y. Feb. 22, 2012), Dkt. No. 58.
[5] - Id.
[6] - Biosig Instruments, Inc. v. Nautilus, Inc., 715 F.3d 891, 895 (Fed. Cir. 2013).
[7] - Id. at 899.
[8] - Id. at 903.
[9] - Id. at 900
[10] - Nautilus, Inc v. Biosig Instruments, Inc., Pet. For a Writ of Cert., 2013 WL 5305648, at *14-15 (2013).


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