On June 2, 2014, the Supreme Court set forth a new test for finding a patent clam indefinite under 35 U.S.C. § 112, second paragraph. The Court held that “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 invention.”

The statutory provision directed to the definiteness requirement is found in 35 U.S.C. §112, ¶2, which requires that “[t]he specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.”1 The public notice function of the claims requires that “claims delineate the patentee’s right to exclude, [and] the patent statute requires that the scope of the claims be sufficiently definite to inform the public of the bounds of the protected invention, i.e., what subject matter is covered by the exclusive rights of the patent.” Halliburton Energy Servs., Inc. v. M-I LLC, 514 F.3d 1244, 1249 (Fed. Cir. 2008).

The Supreme Court granted certiorari in Nautilus v. Biosig Instruments (13-369) on January 10, 2014, to decide the proper standard for finding patented claims indefinite under 35 U.S.C. § 112. According to recent Federal Circuit cases, a patent claim passes the §112, ¶2 threshold so long as the claim is “amenable to construction,” and the claim, as construed, is not “insolubly ambiguous.” See Biosig Instruments, Inc. v. Nautilus, Inc., 715 F.3d 891, 898-899 (Fed. Cir. 2013); Datamize, LLC v. Plumtree Software, Inc., 417 F.3d 1342, 1347 (Fed. Cir. 2005); see also Star Scientific, Inc. v. R.J. Reynolds Tobacco Co., 537 F.3d 1357, 1371 (Fed. Cir. 2008) (“if reasonable efforts at claim construction result in a definition that does not provide sufficient particularity and clarity to inform skilled artisans of the bounds of the claims, the claim is insolubly ambiguous and invalid for indefiniteness”).

In Nautilus, the Court concluded that that “the Federal Circuit’s formulation, which tolerates some ambiguous claims but not others, does not satisfy the statute’s definiteness requirement.” The Court stated that “[t]o 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.’” Further, the Court stated that the “expressions ‘insolubly ambiguous’ and ‘amenable to construction,’ which permeate the Federal Circuit’s recent decisions concerning §112, ¶2 … leave courts and the patent bar at sea without a reliable compass.”

Accordingly, in place of the “insolubly ambiguous” standard, the Court held that “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 invention.”

Justice Ginsburg, writing the opinion of the Court, believed that this standard “mandates clarity” “to afford clear notice of what is claimed” (so as not to inhibit enterprise and experimentation), “while recognizing that precision is unattainable” (because of the limitations of language; because some modicum of uncertainty is the price of ensuring appropriate incentives for innovation; and because patents are addressed to those skilled in the relevant art).

The Court did not apply this standard to the facts in the Nautilus case, remanding the case back to the Federal Circuit to perform the analysis according to the Court's stated standard.

The definiteness requirement of 35 U.S.C. § 112 applies both at the USPTO during prosecution of a patent application and in federal courts during litigation of a granted patent. The Court’s holding in Nautilus does not have any direct effect on prosecution. This is because claims under examination in the Patent Office are evaluated under a different standard than patented claims before a federal court. During prosecution, the U.S. Patent Office interprets claims in the broadest reasonable manner and will find a claim indefinite when it is open to more than one reasonable interpretation. See Ex parte Miyazaki, 89 USPQ2d 1207, 112 (Bd. Pat. App. & Int. 2008). The different threshold for claims under examination is based on a patent record that is still in development and the applicant’s ability to amend claims to overcome an indefiniteness rejection. See, e.g., MPEP 2173. In other words, while the threshold for finding a claim indefinite may be lower, a patent applicant has the flexibility to address indefiniteness problems by argument or amendment. Applicants and practitioners would be well-advised to add sufficient levels of claim definition, and claims of varying scope, to comply with the reasonable certainty guidelines set forth in Nautilus. Additional guidance will likely stem from the Federal Circuit’s analysis of the facts measured against this standard.