The U.S. Court of Appeals for the Federal Circuit reversed a district court claim construction finding the meaning of a claim term to be context-specific. The Court held that such a construction made infringement unpredictable and was thus inconsistent with the notice function of the patent system. Paragon Solutions, LLC. v. Timex Corp., Case No. 08-1516 (Fed. Cir., May 22, 2009) (Linn, J.).

Paragon sued Timex for infringing its patent on an exercise monitoring system. As issued, the claimed patented system includes a “data acquisition unit” that measures data such as location and heart rate and a “display unit” configured to output “real-time” data during exercise. As originally filed, the application claimed a single structure device. During prosecution, in order to avoid a prior art reference, the claimed system was separated into two, separately claimed “units” and the “real-time” data limitation was added.

The accused Timex device has a delay of up to four seconds, and the device is split into three parts, with two separate parts for data acquisition. Timex argued that Paragon’s “data acquisition unit” must be a single structure because it was amended during prosecution to be structurally separate from the display unit. The district court agreed. Timex also argued that the claim term “real-time” meant “instantaneous.” Here, the court accepted Paragon’s view that the meaning of “real-time” could differ depending on the situation and construed the term to mean “without contextually meaningful delay.” However, since the court had agreed with Timex’s construction of “data acquisition unit,” it concluded that Paragon’s claimed two-part structure could not read on Timex’s three-part device. Paragon stipulated to non-infringement and appealed.

On appeal, the Federal Circuit held that the trial court’s construction of “data acquisition unit” was incorrect. Applying the rule that a disavowal of scope during prosecution history must be clear and unmistakable, the Court held that while Paragon had clearly disavowed the single structure device in the prior art, it had not clearly disavowed a device of more than two parts.

The Court then turned to Timex’s argument concerning the correct meaning of the claim term “real-time” as used as in the functional part of a means plus function claim element “display unit configured for displaying real time data.” Noting that five types of claimed “real-time” data require multiple measurements before they can be calculated, the Court reasoned that “real-time” could not mean “instantaneous,” because the device required at least some delay for computation and transmission. However, the Court also disagreed with the district court’s context-specific construction, noting that construing a non-functional apparatus claim would improperly make direct infringement turn on use. For example, a thirty-second delay would be “real-time” for an activity such as walking, but not for running or skiing. The Court reasoned that such a use-specific construction would make infringement unpredictable and was thus “inconsistent with the notice function central to the patent system.” Thus, the Court found that the proper meaning of “real-time” was “without intentional delay, taking into account the processing limitations of the system.”

Based on the new claim construction, the Court vacated the non-infringement ruling and remanded the case back to the district court.