Supreme Court rules that “insolubly ambiguous” standard permits too much ambiguity

September 6, 2014
News | Patents

Nautilus, Inc. v. Biosig Instruments, Inc. On June 2, 2014, the Supreme Court held that the indefinite standard used by the Federal Circuit – “insolubly ambiguous” – was too lenient as it permitted some measure of ambiguity, and therefore did not satisfy the definiteness requirement under 35 U.S.C. 112, second paragraph. In its place, the Supreme Court established a new standard of indefiniteness: “a patent is invalid for indefiniteness if its 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 patent.” (emphasis added)

Biosig’s patent is directed to a heart rate monitor for use in association with exercise equipment having a structure that is gripped by the user, the structure having two sets of electrodes, wherein the electrodes in each set were “in spaced relationship with each other.” On a summary judgment motion from Nautilus, the district court held the claims of Biosig’s patent to be invalid on grounds that the term “spaced relationship” was indefinite.

The Federal Circuit reversed. They initially stated that the claims were “amenable to construction” and, therefore, the claims would only be indefinite if the person of ordinary skill in the art would find “spaced relationship” to be “insolubly ambiguous.” The Federal Circuit found that the specification of the patent disclosed “inherent parameters” and the claims recited functional limitations which would permit a skilled artisan to sufficiently understand the metes and bounds of “spaced relationship,” and therefore the claims were not insolubly ambiguous.

The Supreme Court found that the Federal Circuit’s approach of assessing indefiniteness by first determining whether the claims were “amenable to construction” and, if so, then determining if the claims were “insolubly ambiguous,” was insufficient as this approach “tolerates some ambiguous claims but not others.” Additionally, the Court stated that the Federal Circuit’s amenable to construction/insolubly ambiguous standard would “breed lower court confusion.” Further, the Court noted that the requirements of §112, second paragraph, should not be considered satisfied merely because “a court can ascribe some meaning to a patent’s claims.” Overall, the Court stated:

To tolerate imprecision just short of that rendering a claim “insolubly ambiguous” would diminish the definiteness requirement’s public-notice function and foster the innovation-discouraging “zone of uncertainty,” United Carbon, 317 U. S., at 236, against which this Court has warned.

The Court described the definiteness requirement as a “delicate balance” which must take into account the limitations of language, and thus permit some modicum of uncertainty, while also ensuring that the claims provide clear public notice so that the public can by apprised of what subject matter is not covered by the claims.

Cognizant of the competing concerns, we read §112, ¶2 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. The definiteness requirement, so understood, mandates clarity, while recognizing that absolute precision is unattainable.

The Court vacated the Federal Circuit decision and remanded for further proceedings consistent with their newly articulated standard for indefiniteness.

Practice Note: Indefiniteness can creep into claims in a variety of ways. One particular situation is the case where an application claims priority to a foreign application. In such a case, the original claims may use language which, although acceptable in the home country, would violate the requirements of 35 USC 112, second paragraph. This becomes even more problematic when the application is allowed in a first Office Action. To the extent possible, the claims should be reviewed before payment of the issue fee, to clear up any potential issues. Preferably, the claims should be reviewed even before the Examiner’s first Office Action on the merits, to avoid the filing of a paper that may adversely affect the PTA calculation.


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