United States: Federal Circuit: Claims Reciting A Term Of Degree Found Not Indefinite In One-E-Way

On June 12, 2017, the U.S. Court of Appeals for the Federal Circuit reversed a finding of indefiniteness that invalidated two patents claiming wireless audio systems in One-E-Way, Inc. v. ITC.1 In this precedential decision, the panel majority found the claim term "virtually free from interference," when viewed in light of the specification and statements made in the prosecution history of a related parent patent, would inform a person of ordinary skill in the art ("POSA") about the scope of the invention with reasonable certainty. While the majority noted that "virtually" is a term of degree that "slightly expands the scope of the term 'free from interference,'" the court found that it did not expand the claim scope "without end." Thus, the term satisfied the definiteness requirement of 35 U.S.C. § 112 ¶ 2. In dissent, Chief Judge Prost stated that "the majority's decision significantly relaxes the law on indefiniteness against the tide of the Supreme Court's recent decision in Nautilus Inc. v. Biosig Instruments, Inc."

The two patents at issue disclose a wireless digital audio system that lets people use wireless headphones privately, without interference. This purportedly solved problems found in prior art systems, which did not provide private listening without interference when multiple users occupied the same space. When the claims were considered before the ITC, the administrative law judge ("ALJ") decided that the term "virtually free from interference" was indefinite, and the Commission affirmed the decision. But on appeal, the Federal Circuit panel majority agreed with One-E-Way's proposal that the term would be understood to mean that it "prevents one user from eavesdropping on another."

The Nautilus test for indefiniteness requires that the "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."2 Furthermore, since patents are presumed valid, "'any fact critical to a holding on indefiniteness must be proven by the challenger by clear and convincing evidence.'"3 As the panel explained, the "indefiniteness requirement is 'part of the delicate balance the law attempts to maintain between the inventors, who rely on the promise of the law to bring the invention forth, and the public, which should be encouraged to pursue innovations, creations, and new ideas beyond the inventor's exclusive rights.'"4 "This balance recognizes that all claims suffer from 'the inherent limitations of language'" and "permits 'some modicum of uncertainty,'" but at the same time "[this balance] also provides a 'meaningful definiteness check' to prevent patent applicants from 'injecting ambiguity into their claims.'"5 Thus, the Nautilus "test 'mandates clarity, while recognizing that absolute precision is unattainable.'"6 Consequently, "[a]s long as claim terms satisfy this test, relative terms and words of degree do not render patent claims invalid."7

After explaining the relevant legal standards, the majority found that "the specification discloses a system that enables wireless headphone users to enjoy their audio privately, without interference." According to the majority, statements in the specification collectively "make clear that private listening is listening without interference from other users," and that "the patented invention sought to prevent such interference [in order for] wireless-headphone users to listen in private."

The panel also considered the prosecution history of the related parent patent to construe the disputed claim term. There, the applicant stated that "[the prior art] does not teach, disclose, or suggest such a relationship where interference is virtually eliminated (e.g. where eavesdropping cannot occur) where multiple receivers and transmitters occupy the same environment" (emphasis in original). Although this statement was made in connection with claims reciting the term "free from interference," the Court held that a POSA would have found the statement instructive as to "virtually free from interference" for two reasons. First, claims reciting "virtually free from interference" were pending approval at the time of this statement. Second, "the very language of the prosecution history statement employs the term 'virtually,'" and thus suggests "[o]n its face . . . that interference, virtually eliminated, results in listening without eavesdropping." Accordingly, the majority found that the term "virtually free from interference" would be understood to prevent one user from eavesdropping on another.

The panel then addressed the Respondents' and ALJ's reasoning that "virtually free from interference" was indefinite because "virtually" does not inform a POSA as to the specific level of interference permitted. Their reasoning was that because there are known, technical methods to measure levels of interference, the patents-in-suit were thus indefinite for failing to instruct on such relevant interference measurements. The majority, however, disagreed, deciding that a lack of a technical definition of the claim term was irrelevant to the issue of definiteness under these circumstances because the specification and prosecution history used the term in a non-technical manner. A POSA would interpret the term in the way the applicant used it in the specification and prosecution history "to simply mean that the wireless headphone user is able to listen without eavesdropping." In such circumstances, "[f]or the purposes of definiteness, the term is not required to have a technical measure of the amount of interference."8

Finally, the panel rejected the Government's and Respondent's arguments that "'virtually free from interference' must be indefinite because One-E-Way fails to identify how it differs in scope from claims that recite the term 'free from interference.'" The court noted that One-E-Way had not asserted any claims reciting "free from interference." Moreover, the court stated that "an understanding of the relative meaning of these terms is readily apparent," and that "[i]t follows that [a POSA] might expect that because audio 'virtually free from interference' is free from eavesdropping, audio 'free from interference' will be, at a minimum, free from eavesdropping as well."

Dissenting from the court's decision, Judge Prost argued that the majority relied too heavily on a "cherry-picked prosecution remark," and "flout[ed] the well-established principle that 'the written description is key to determining whether a term of degree is indefinite.'"9 Judge Prost found that "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." The dissent further stated that "the remainder of the intrinsic evidence . . . either remains silent or injects ambiguity," leaving a POSA with "simply not enough" information to "determine the boundaries of the limitation, much less the import of the word 'virtually.'" As a result, the dissent found that this "falls far short of the level of clarity required . . . under Nautilus and skirts the public-notice function of the definiteness requirement."


1 One-E-Way, Inc. v. Int'l Trade Comm'n, No. 2016-2105, slip op. (Fed. Cir. June 12, 2017).

2 Id. at 7 (citing Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120, 2129 (2014)) (quotations omitted).

3 Id. at 7 (quoting Cox Commc'ns, Inc. v. Sprint Commc'n Co. LP, 838 F.3d 1224, 1228 (Fed. Cir. 2016) (alterations to quotation omitted)).

4 Id. at 7 (quoting Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 731 (2002)).

5 Id. at 7 (quoting Nautilus, 134 S. Ct. at 2128-29 (alterations to quotation omitted)).

6 Id. at 7 (quoting Nautilus, 134 S. Ct. at 2129).

7 Id. at 8.

8 Id. at 14.

9 Slip op., Prost Dissent at 2 (quoting Sonix Tech. Co. v. Publ'ns Int'l Ltd., 844 F.3d 1370, 1378 (Fed. Cir. 2017)).

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