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

Last Updated: August 5 2014
Article by Thomas G. Hungar and Blair A. Silver

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.

A. 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 width of each electrode." Id. The district court ultimately construed the term to mean "there is a defined relationship between the live electrode and the common electrode on one side of the cylindrical bar and the same or a different defined relationship between the live electrode and the common electrode on the other side of the cylindrical bar"--without any reference to the electrodes' width. Id.

Nautilus moved for summary judgment of invalidity, arguing that the term "spaced relationship" as construed was indefinite under § 112, ¶ 2. Id. The district court granted the motion because "spaced relationship" "did not tell [the court] or anyone what precisely the space should be" and did not supply "any parameters" for determining the appropriate spacing. Id., slip op. at 6-7.

On appeal, the Federal Circuit reversed and remanded. The majority opinion stated that "[a] claim is indefinite only when it is not amenable to construction or insolubly ambiguous." Biosig Instruments, Inc. v. Nautilus, Inc., 715 F.3d 891, 898 (Fed. Cir. 2013) (citing Datamize, LLC v. Plumtree Software, Inc., 417 F.3d 1342, 1347 (Fed. Cir. 2005)) (internal quotation marks omitted). Applying that standard to the term "spaced relationship" in light of the intrinsic evidence--i.e., the specification and prosecution history--the majority concluded that the term was not insolubly ambiguous and thus survived scrutiny under its precedent. Id. at 898-902. Judge Schall concurred in the result and applied the same test but adopted a different construction of the disputed term. Id. at 905-06.

B. The Supreme Court's Decision in Nautilus

The Supreme Court overturned the Federal Circuit's articulation of the standard for determining whether a patent claim is indefinite. Nautilus argued to the Court that the Federal Circuit's test was too permissive, and urged the Court to adopt a higher standard. Biosig and the Solicitor General responded that the patent need only provide "reasonable notice of the scope of the claimed invention." Nautilus, 572 U.S. ___ (2014) (slip op. at 9).

Justice Ginsburg, writing for the unanimous Court, sided with Nautilus, rejecting the test applied by the Federal Circuit because it "lack[ed] the precision § 112, ¶ 2 demands." Id., slip op. at 12. The Court criticized the Federal Circuit's standard as possibly breeding confusion, leaving courts and the patent bar "at sea without a reliable compass." Id., slip op. at 11, 13. It is not enough, the Court stated, that a court can "ascribe some meaning to a patent's claim." Id., slip op. at 12. The Court reiterated that the proper inquiry focuses on the "understanding of a skilled artisan at the time of the patent application, not that of a court viewing matters post hoc." Id.

The Court articulated the delicate balance of two competing concerns surrounding definiteness: promoting innovation and providing clear notice to the public. Id., slip op. at 9-10. Reconciling these two concerns, the Court adopted a more exacting standard for definiteness: 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. Declining to apply its newly formulated test, the Court remanded the case to the Federal Circuit to reconsider whether the relevant claims in the '753 patent are sufficiently definite. Id., slip op. at 14.

In articulating the new test, the Court acknowledged that the Federal Circuit test was particularly problematic because without a "meaningful definiteness check . . . patent applicants face powerful incentives to inject ambiguity into their claims." Id., slip op. at 10. "Eliminating that temptation," the Court offered its new test for definiteness to achieve "clarity, while recognizing that absolute precision is unattainable." Id., slip op. at 10-11. The Court also rejected the argument that the presumption of validity was a basis for having a permissive standard of definiteness. Id., slip op. at 13 n.10.

Nautilus thus strengthens the ability of alleged infringers to prevail on indefiniteness defenses against patent claims. The effect of this should ultimately lead to clearer patents, but the precise contours of the reasonable certainty test will have to be fleshed out in future cases by the Federal Circuit. It remains to be seen how vigorously the Federal Circuit on remand and other courts will apply the new standard.

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