A claim limitation is indefinite if, read in light of the specification delineating the patent, and the prosecution history, it fails to inform, with “reasonable certainty,” those skilled in the art about the scope of the invention. This “reasonably certainty” standard replaces the Federal Circuit’s “insolubly ambiguous” inquiry, although the Supreme Court at least hinted that this change may be one more of name than practice.

Background / Facts: This case, involving a heartrate monitor used with exercise equipment, concerns the proper reading of the patent statute’s clarity and precision demand under §112, ¶2.

Issue(s): Whether the Federal Circuit’s definiteness standard requiring claims to simply be “amenable to construction” and not “insolubly ambiguous” is the proper interpretation of §112, ¶2.

Holding(s): No. Although recognizing that the phrase “insolubly ambiguous” may be “a shorthand label for a more probing inquiry that the Federal Circuit applies in practice,” the Supreme Court concluded that “the Federal Circuit’s formulation, which tolerates some ambiguous claims but not others, does not satisfy the statute’s definiteness requirement.” “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.’” Instead, “[c]ognizant of the competing concerns, we read §112, ¶2 to require that a patent’s claims, viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty.”

Full Opinion