Addressing claim indefiniteness, the US Court of Appeals for the Federal Circuit concluded that the claim term “virtually free from interference” was sufficiently definite to pass § 112 muster. One-E-Way, Inc. v. Sony Corp., Case No. 16-2105 (Fed. Cir., June 12, 2017) (Stoll, J) (Prost, CJ, dissenting).

One-E-Way brought a US International Trade Commission (ITC) investigation, asserting two patents on a wireless audio system designed to let people use wireless headphones privately, without interference. The asserted claims recited transmitting audio “virtually free from interference.” The respondents and the ITC Office of Unfair Import Investigations argued that the claim term “virtually free from interference” was indefinite. One-E-Way proposed a construction for the term of “free from interference such that eavesdropping on device transmitted signals operating in the wireless digital audio system spectrum cannot occur.” The administrative law judge found the disputed term to be indefinite, and the full ITC agreed. One-E-Way appealed.

A divided Federal Circuit panel determined that the term “virtually free from interference” would inform a person of skill in the art about the scope of the invention with reasonable certainty and reversed the ITC. Writing for the majority, Judge Stoll relied on the patent specification and the prosecution history of a related parent patent. Since the specification did not provide boundaries for the term “virtually,” the majority focused on the prosecution history. There, the applicant asserted that the cited prior art “does not teach, disclose, or suggest such a relationship where interference is virtually eliminated (e.g. where eavesdropping cannot occur).” Based on this prosecution statement, the majority concluded that the term “virtually free from interference” satisfied the definiteness standard.

Chief Judge Prost dissented. She found that a person skilled in the art could not determine the boundaries of “virtually free from interference” based on the intrinsic record:

Here, the intrinsic evidence, at best, mentions one example for determining when audio is “virtually free from interference,” and that example only appears in a single “e.g.” remark from the prosecution history of a related patent. Viewed alongside the remainder of the intrinsic evidence, which either remains silent or injects ambiguity, there is simply not enough for a person of ordinary skill to determine the boundaries of the limitation, much less the import of the word “virtually.”

Chief Judge Prost found that “the majority’s decision significantly relaxes the law on indefiniteness against the tide of the Supreme Court’s 2014 decision in Nautilus v. Biosig Instruments”.