One-E-Way, Inc. v. ITC: Clarity of Claim Term Provided by Statement in the Prosecution History

In a recent Federal Circuit decision, the court found that a single statement made during prosecution of a patent family lent sufficient clarity to the claim term at issue. ¹

The patent at issue is part of a patent family that involves wireless digital audio music transmission. ² The patents describe a “wireless digital audio music system [that] provides private listening without interference from other users or wireless devices and without the use of conventional cable connections.” ³

The family of patents include an earlier patent claiming a system that is “free from interference.” ⁴ During the prosecution of this earlier patent, the patentee asserted that the prior art “does not teach, disclose, or suggest such a relationship where interference is virtually eliminated (e.g., where eavesdropping cannot occur).” ⁵ That earlier patent was not, however, asserted in this suit. Rather, the patentee asserted two later patents that were amended during prosecution to recite the term “virtually free from interference from device transmitted signals operated in the wireless headphone spectrum.” ⁶

After the patentee asserted the two patents before the Internal Trade Commission (“ITC”), the ITC agreed with the respondents’ defense that the term “virtually free from interference” is indefinite. ⁷ The ITC appears to have considered the claim language to be a term of degree that was not properly defined or explained in the specification. ⁸ The patentee, on the other hand, asserted that the claim language was properly explained in the prosecution history of the earlier patent, in which the patentee overcame the prior art based on the claim language of “free from interference,” and argued that the prior art “does not teach, disclose, or suggest a relationship where interference is virtually eliminated (e.g., where eavesdropping cannot occur).” ⁹ Based on this single statement in the prosecution history, the patentee asserted that the term “virtually free from interference” is definite and means “free from interference such that eaves dropping on device transmitted signals operating in [the] wireless digital audio spectrum cannot occur.” ¹⁰

The Federal Circuit agreed with the patentee, and reversed the ITC. It held that the specification and the prosecution history provided sufficient clarity as to the interpretation of “virtually free from interference,” and further agreed with the patentee’s proposed claim interpretation, namely that of “free from interference such that eaves dropping on device transmitted signals operating in the wireless digital audio system spectrum cannot occur.” ¹¹

In particular, the Federal Circuit pointed to the patentee’s statement in the prosecution history of the earlier patent, in which it asserted that the prior art lacked a relationship where “interference” is “virtually” eliminated (e.g., where “eavesdropping” cannot occur). ¹² Although certain terms of this definition, such as “eavesdropping,” were not found in the specification, the Federal Circuit found that such terms are consistent with the objective of “private listening” discussed in the specification. ¹³ Thus, according to the court, the “patented invention sought to prevent . . . interference, making it possible for wireless-headphone users to listen in private.” ¹⁴

The Federal Circuit further addressed the respondents’ argument that it is unclear how the claim language of “virtually free from interference” differs from “free from interference.” In other words, the respondents argued that the term “virtually,” used as a modifier, had unclear scope. The Federal Circuit acknowledged that the patentee “did not define the scope of the term . . . in a technical sense as [the ITC and respondents] would seemingly require,” but stated that “the lack of a technical definition does not render the term indefinite.” ¹⁵ It reasoned that the term “’free from interference’ . . . will be a bit better than audio ‘virtually free from interference,’ in the same way something ‘free from defects’ will be a bit better than something substantially or ‘virtually free from defects.’”¹⁶ “It follows that one of ordinary skill might expect that because ‘virtually free from interference’ is free from eavesdropping, audio ‘free from interference’ will be, at a minimum, free from eavesdropping as well.”¹⁷

Chief Judge Prost dissented, disagreeing with the majority’s opinion primarily because, in his view, the patentee relied too heavily on a single statement in the prosecution history rather than on the actual specification, and because the record provided insufficient guidance on the scope of the modifier “virtually.”¹⁸ More particularly, the dissent emphasized that the written description, rather than statements in the prosecution history, should be the “key” to the indefiniteness inquiry for a term of degree.¹⁹ It further reasoned that while a term of degree such as “virtually” can be used in a patent, the specification in this instance simply did not provide sufficient guidance as to the objective boundaries of the term. ²⁰ Further, the dissent pointed out that the patentee’s statement in the prosecution history regarding a lack of “e.g.,” eavesdropping at most provides only an example of a standard that is virtually free from interference, and does not sufficiently define the boundaries of that standard. ²¹

While the patentee prevailed in this appeal, One-E-Way demonstrates the importance of careful patent drafting and prosecution. In particular, it reinforces the value of drafting a specification that mirrors the language of the claims, of relying on the language of the specification when amending the claims, and of keeping claim language consistent across different claims in a single application and in a family of applications.