On June 2, 2014, the Supreme Court issued a unanimous decision in Nautilus, Inc. v. Biosig Instruments, Inc., rejecting the Federal Circuit’s “insolubly ambiguous” test for patent claim indefiniteness under 35 USC § 112, and instead adopting a “reasonable certainty test.” The Court vacated the Federal Circuit decision rendered under the “insolubly ambiguous” test, and remanded for the Federal Circuit to evaluate Biosig’s claims under the new standard.
The Patent at Issue
The patent at issue was Biosig’s U.S. Patent 5,337,753, directed to a heart rate monitor associated with an exercise apparatus and/or exercise procedures. At issue was claim language regarding a “spaced relationship” between electrodes positioned on an “elongate member” that is held by the user to obtain a heart rate measurement. (Please see for a more detailed discussion of this case.)
The Prior Proceedings
The district court construed the term “spaced relationship” to mean that “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,” and held the term indefinite because it “did not tell me or anyone what precisely the space should be . . . . Not even any parameters as to what the space should be . . . . Nor whether the spaced relationship on the left side should be the same as the spaced relationship on the right side.”
The Federal Circuit reversed, applying an “insolubly ambiguous” test that would hold a claim indefinite only if it is “not amenable to construction.” With reference to the claim language at issue, the court stated:
When a “word of degree” is used, the court must determine whether the patent provides “some standard for measuring that degree.” …. Similarly, when a claim limitation is defined in “purely functional terms,” a determination of whether the limitation is sufficiently definite is “highly dependent on context (e.g., the disclosure in the specification and the knowledge of a person of ordinary skill in the relevant art . . . ).”
The court determined that the “claim language, specification, and … figures” of the ‘753 patent “provide sufficient clarity to skilled artisans as to the bounds of this disputed term.”
The Supreme Court Decision
The Supreme Court decision recognizes that the standard for indefiniteness must balance two competing interests: permitting “[s]ome modicum of uncertainty” to provide “appropriate incentives for innovation” while requiring enough precision “to afford clear notice of what is claimed” and disincentivize the deliberate creation of “zone[s] of uncertainty” around claim scope. The Court determined that these interests are best balanced when the statute is read “to require that 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.”
Although the Court took some time to explain the questions presented by the claims at issue, it refused to apply the new “reasonable certainty” test in the first instance, instead remanding to the Federal Circuit. Thus, it will be up to the Federal Circuit in the first instance to determine how to assess whether Biosig’s claims define its invention with “reasonable certainty”.
Unreasonable Uncertainty
Although the Supreme Court calls for “reasonable certainty” in claim language, its decision leaves a “zone of uncertainty” around what is required to satisfy § 112. By pronouncing a new test without applying it to the claims at issue, the Court does little more than discredit the Federal Circuit’s approach without providing even a “modicum” of guidance on the correct standard.