Yesterday, the United States Supreme Court raised the standard of definiteness that patent claims must satisfy in order to be upheld as valid. Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. ___ (2014). Under prior Federal Circuit precedent, a claim would not be invalidated as indefinite as long as the claim was “amenable to construction” and not “insolubly ambiguous.” Id. Now, a claim will be found invalid if the claim fails to inform persons of skill in the art (as measured “at the time the patent was filed”) about the scope of the claim “with reasonable certainty.” Id.

While the Supreme Court recognized that “[s]ome modicum of uncertainty” was the “price of ensuring appropriate incentives for innovation,” the Court rejected the Federal Circuit’s “insoluble ambiguity” test and explained:

“To 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.’” Id.

The Supreme Court cautioned that “a patent must be precise enough to afford clear notice of what is claimed, thereby ‘apprising the public of what is still open to them.’” Id. “Otherwise there would be ‘[a] zone of uncertainty which enterprise and experimentation may enter only at the risk of infringement claims.’” Id.

Previously, patentees were able to create (and then later exploit) a “zone of uncertainty” around their claims by drafting ambiguous claims, the scope of which could be ascertained only in later litigation when a court announced which side’s claim construction arguments the court found most persuasive. The new “reasonable certainty” standard should help curtail this practice by reducing the zone of uncertainty surrounding patent claims and enhancing the public-notice function of patents. The new standard also will make it easier for defendants to attack the validity of ambiguous claims asserted in litigation.