In a unanimous decision yesterday, the U.S. Supreme Court overturned the Federal Circuit's standard for determining whether patent claims are indefinite under 35.U.S.C. § 112, ¶2 in Nautilus, Inc. v. Biosig Instruments, Inc.¹ The Supreme 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."²

35 U.S.C. § 112, ¶2 requires that a patent specification "conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as [the] invention."³ The Federal Circuit held that a patent claim meets this statutory threshold so long as the claim is "amenable to construction" and that, as construed, is not "insolubly ambiguous."⁴ Wary of how the patent system may afford powerful incentives to inject ambiguity into patent claims, the Supreme Court criticized the Federal Circuit's test for "diminishing the definiteness requirement's public-notice function" and for "fostering the innovation-discouraging zone of uncertainty."⁵ The Supreme Court also criticized the Federal Circuit's test for breeding confusion among district courts.⁶

In formulating its "reasonable certainty" test for indefiniteness, the Supreme Court balanced the inherent limitations of language against the requirement that a patent must be precise enough to afford clear notice of what is claimed.⁷ It also acknowledged the parties' agreement that: (1) definiteness is to be evaluated from the perspective of someone skilled in the relevant art, (2) claims are to be read in light of the patent's specification and prosecution history, and (3) definiteness is measured from the viewpoint of a person skilled in the art at the time the patent was filed.⁸ While rejecting the Federal Circuit's standard and presenting a new test, the Supreme Court vacated and remanded without determining whether the patent-at-issue was indefinite under the new standard, stating that the Court was one of review, not of first view.⁹

Even though the new test has not yet been applied, the Supreme Court's decision ostensibly lowers the standard for district courts to determine whether patent claims are indefinite, which may make it easier for defendants to challenge the validity of ambiguous patents.

¹ Nautilus, Inc. v. Biosig Instruments, Inc., No. 13-369, 572 U.S. ___ (2014).

² Id., slip op. at 1.

³ Id. (emphasis removed) (citing 35 U.S.C. § 112, ¶2 (2006 ed.)).

⁴ Nautilus, slip op. at 1.

⁵ Id. at 10.

⁶ See id. at 11-12.

⁷ Id. at 9-10.

⁸ Id. at 8-9.

⁹ Id. at 14.