New Standard for Indefiniteness of Patent Claims

This month’s unanimous Supreme Court decision in Nautilus, Inc. v. Biosig Instruments, Inc. provided guidance in determining “indefiniteness” of patent claims. The Patent Act 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.” 35 U.S.C. § 112 (2012). The Federal Circuit had interpreted that language to mean that a patent claim must be “amenable to construction” and not “insolubly ambiguous.” The Supreme Court turned that on its head in Nautilus, holding that the Federal Circuit’s interpretation of that language lacked the precision that the statute required. Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120, 2131 (2014).

The case involved a patent on a heart-rate monitor used with exercise equipment. This heart-rate monitor was more accurate than previous monitors because it detected the electrical signals accompanying each heart beat without interference from other electrical signals generated by the user’s skeletal muscles.

In describing the technology, the claim language included a live electrode and a common electrode “mounted . . . in spaced relationship with each other” but did not identify specifically what the spaced relationship was with measurements or other description. The district court construed “spaced relationship” to mean “there is a defined relationship between the live electrode and the common electrode on one side of the cylindrical bar and the same or a different defined relationship between the live electrode and the common electrode on the other side of the cylindrical bar.” Based upon that claim construction, the district court granted Nautilus’s motion for summary judgment on the ground that the claim language did not satisfy the Patent Act’s definiteness requirement.

The Federal Circuit reversed, holding that the claim met the definiteness requirement because it was amenable to construction and was not insolubly ambiguous. The Court reasoned that a skilled artisan would be able to find appropriate boundaries for the “spaced relationship.” Extrinsic evidence was also considered, including a declaration from the inventor who asserted that the patent claim was sufficiently specific to allow a person “skilled in the art” to understand how to place the electrodes.

The Supreme Court vacated the judgment of the Federal Circuit, holding that the standard for definiteness applied by the Federal Circuit was too liberal. And it articulated that patent claims are indefinite if “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.” Nautilus, 134 S. Ct. at 2131.

The Court reasoned that the monopoly provided to a patent holder is a property right and, as a property right, its boundaries must be clearly defined. It is not enough, under Section 112, for the claim to be only definite enough to allow a court to ascribe some meaning to it. To construe the statute as requiring that patent claims must only be “amenable to construction” would diminish the public notice function that the statute serves. Because the Federal Circuit’s test did not require enough precision in patent claims, it could “leave courts and the patent bar at sea without a reliable compass.” Id. at 2130.

Going forward, there is an increased likelihood for patents subject to litigation to be invalidated based on the Supreme Court’s decision. The definiteness test is now more in line with the statute itself and provides accused infringers an easier standard for challenging validity than the Federal Circuit’s previous “insolubly ambiguous” standard. While the courts will take time to realize the full impact of this decision, both patent owners and accused infringers will need to consider this lower standard for invalidity during prosecution and litigation.