In yet another unanimous opinion—Nautilus, Inc. v. Biosig Instruments, Inc.—the US Supreme Court
rejected the Federal Circuit’s standard and laid out a new standard for patent claims to meet the definiteness requirement of the Patent Act.1 This section of the Patent Act requires that claims particularly point out and distinctly claim the subject matter of the invention.2 Patents confer property rights; therefore, claims must be sufficiently definite to provide notice to the public of the bounds of the patent-protected invention.

The asserted claim in Nautilus was directed to a heart-rate monitor used with exercise equipment and containing two electrodes “in spaced relationship with each other.”  The district court held that the claim term “spaced relationship” was indefinite because the patent offered no guidelines regarding the positioning of the two electrodes with respect to each other.  The Federal Circuit’s long-standing formulation3 was that a claim is indefinite only when it is “not amenable to construction” or is “insolubly ambiguous.”4 Using this standard, the Federal Circuit found the claim language, specification and the figures illustrating the “spaced relationship” provided sufficient guidance to one skilled in the art as to the bounds of the claim term, and reversed the district court decision.

Although the Supreme Court has not reviewed the definiteness doctrine in detail in over seventy years,5it continued its recent trend of unanimous rejections of the Federal Circuit standards in patent law cases, thus forcing the Federal Circuit to adhere more strictly to Supreme Court precedent.  The Court focused on possible confusion resulting from imprecise words such as “amenable to construction” and “insolubly ambiguous,” while claiming that it did not intend to “micromanage the Federal Circuit’s particular word choice in applying patent-law doctrines.”6 The Supreme Court voiced interests in ensuring that the tests formulated by the Federal Circuit are at least “probative of the essential inquiry.”7

The Court recognized the competing concerns between the limitations of the written language and the public notice required for enjoying the monopoly granted by a patent.  Relying on its own precedent requiring "reasonable certainty,"8 the Supreme Court articulated a more precise standard:  "A patent is invalid for indefiniteness if its claims, read in light of the patent’s specification and prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention."  Therefore, the burden is back on the Federal Circuit to examine the definiteness of the claims under the new standard.

Whether the standard articulated in Nautilus will apply for both pre-issuance and post-issuance challenges remains to be seen.  Recently in a controversial opinion—In re Thomas G. Packard, the Federal Circuit claimed to address an issue distinct from the issues raised in Nautilus.  The Federal Circuit distinguished between indefiniteness challenges that arise pre-issuance at the USPTO and post-issuance at the District Court, and clearly indicated that the USPTO and district courts may use different standards for indefiniteness.9   Interestingly, in a footnote in the Nautilus decision, the Supreme Court points to the examination standard in the USPTO’s Manual of Patent Examining Procedure as an example of permeation of Federal Circuit’s imprecise expressions.10 Given that the Supreme Court has not addressed the different standards issue, new questions arise regarding the applicable standards for definiteness challenges during post-grant proceedings at the Patent Trial and Appeal Board.  The tensions between the Federal Circuit and the Supreme Court are far from being over.