Intellectual Property Law: Counseling, Licensing, Litigation & Procurement

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Nautilus v. Biosig

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In Nautilus v. Biosig, the Supreme Court reviewed the Federal Circuit’s test for invalidating an issued patent on grounds of indefiniteness under 35 U.S.C. § 112(b) (pre-AIA). In particular, petitioner Nautilus urged the Supreme Court to reject the Federal Circuit’s requirement that the alleged infringer prove, by clear and convincing evidence, that claims are “insoluble,” i.e., that the claim is “not amenable to construction.”

Patent claims, in delineating the patentee’s right to exclude others from making, using and selling the invention, play a critical role in enforcing the core public interests lying at the foundation of the United States patent system. If the patentee fails to draft claims of sufficient precision and definiteness, the public is not adequately informed of the bounds of the protected invention. Instead, the carefully prescribed rights provided to the patentee are inflated, and the contribution to science lessened. Thus, 35 U.S.C. § 112(b) requires that patent claims “particularly point[] out and distinctly claim[]” the claimed subject matter; and failure to do so renders the patent indefinite and therefore invalid and unpatentable.

At the Federal Circuit, a three-judge panel held that the term “spaced relationship” did not suffer from indefiniteness. Although “spaced relationship” arguably permitted multiple, reasonable interpretations by those skilled in the art, the claim was nonetheless amenable to a construction, and therefore, not “insoluble.” Petitioner Nautilus asked the high court to address whether “the Federal Circuit’s acceptance of ambiguous patent claims with multiple reasonable interpretations — so long as the ambiguity is not ‘insoluble’ by a court — defeat[s] the statutory requirement of particular and distinct patent claiming.”

The Federal Circuit’s test for indefiniteness, Nautilus argued, allows for unreasonable advantages to the patentee and disadvantages to others arising from uncertainty as to their respective rights. This “zone of uncertainty which enterprise and experimentation may enter only at the risk of infringement claims” stifles innovation. Moreover, Nautilus asserted, allowing claims with multiple, reasonable interpretations incentivizes patent drafters to purposefully obfuscate their invention. This may lead to further downstream problems for the judicial system, where courts are forced to “spend a substantial amount of judicial resources trying to make sense of unclear, overbroad, and sometimes incoherent claim terms.”

During Supreme Court arguments on April 28, 2014, Nautilus held that whenever, after applying the tools of claim construction, a patent claim is subject to more than one reasonable construction, i.e., whenever it is ambiguous, it should be ruled indefinite. Nautilus argued that patent attorneys can easily draft claims which are not ambiguous, but that economic incentives lead to the drafting of overly broad and ambiguous claims.

Counsel for Biosig argued the Federal Circuit correctly held that the claims were definite because their bounds were understood, and that the claims’ functional language shed additional light on the “spaced relationship” limitation. Biosig also pointed to evidence that a person skilled in the art could make the invention in only a few hours after reading the patent, and argued that the patent law has long permitted some amount of experimentation.

Biosig urged that the Supreme Court’s decision in Markman contemplated that there would be disputes between reasonable constructions of patent terms, and that patents should not be held invalid merely because there is more than one possible interpretation. Biosig agreed that a patent should be found invalid when there are two “equally plausible” constructions, but argued that indefiniteness should not be found if “the right answer is appreciably better than the second best answer.”

In a unanimous decision delivered by Justice Ginsburg on June 2, 2014, the Supreme Court rejected the Federal Circuit’s articulation of the definiteness standard, which it said “tolerates some ambiguous claims but not others.” The High Court ruled that “[i]n place of the ‘insolubly ambiguous’ standard, we hold 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 Court emphasized the patent law’s competing concerns between encouraging innovation and providing adequate public notice of patent rights. The Court said that the newly announced “reasonable certainty” standard strikes an appropriate balance between these concerns by “mandat[ing] clarity, while recognizing that absolute precision is unattainable.”
Although the Court disagreed with the Federal Circuit’s articulation of the appropriate test for indefiniteness, it did not address the underlying question of whether the claims at issue are definite. The case was remanded to the Federal Circuit to consider this question in light of the Court’s decision.

Important Dates


  • June 2, 2014 – U.S. Supreme Court issues decision
  • April 28, 2014 – U.S. Supreme Court hears oral argument
  • Jan. 10, 2014 – U.S. Supreme Court grants Nautilus’ petition for a writ of certiorari
  • Sept. 21, 2013 – Nautilus files petition for a writ of certiorari
  • June 28, 2013 – Federal Circuit denies en banc rehearing request
  • April 26, 2013 – Federal Circuit issues decision

Court Documents


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Intellectual Property Law: Counseling, Licensing, Litigation & Procurement