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Claims Limited to the Preferred Embodiment When It Is the Only Disclosed Embodiment and Its Features Touted as Important

May 11, 2006
Frederick, Mareesa A.

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Last Month at the Federal Circuit - June 2006

Judges: Newman (author), Dyk, Prost

In Inpro II Licensing, S.A.R.L. v. T-Mobile USA, Inc., No. 05-1233 (Fed. Cir. May 11, 2006), the Federal Circuit held that the district court correctly construed the claim limitation “host interface” and affirmed the judgment of noninfringement.

Inpro II Licensing, S.A.R.L.’s (“Inpro”) U.S. Patent No. 6,523,079 (“the ’079 patent”) relates to a personal digital assistant (“PDA”) designed to overcome the drawbacks associated with prior PDA devices. Specifically, the ’079 patent describes the prior PDA devices as costly, bulky, and problematic. For example, when the user attempted to transfer data from the PDA to a host computer, the transfer was often slow and error prone. The invention of the ’079 patent, however, overcame those drawbacks.

Specifically, Inpro designed its PDA with improved features, such as a thumbwheel controller with a host interface, that eliminated the problems confronted by the prior art. This design allowed the PDA to “run independently by its own internal [CPU] until it is connected to a host computer. Upon connection to the host computer, the host CPU takes control and can access the memory and other functional units of the PDA.” Slip op. at 3. According to the specification of the ’079 patent, this feature represented a marked improvement over the prior art.

Inpro sued T-Mobile USA, Inc. and others (collectively “T-Mobile”), alleging that T-Mobile infringed claims 34, 35, and 36 of the ’079 patent. T-Mobile counterclaimed seeking a declaration of noninfringement and invalidity. The district court held a Markman hearing and construed eight claim terms. Based on the district court’s claim construction, Inpro stipulated to noninfringement and the district court entered final judgment in favor of T-Mobile. Inpro then appealed the construction of three of the claim terms: “host interface,” “docking with the host computer,” and “digital assistant module.”

On appeal, the Federal Circuit’s analysis of the claim construction focused on the term “host interface,” which the district court had construed as “a direct parallel bus interface.” Relying on the doctrine of claim differentiation, Inpro argued that because some of the unasserted claims recited a “parallel bus interface” and a “direct access” parallel bus, claim 34 should not have been limited to a parallel bus interface involving direct access. Moreover, according to Inpro, the district court had improperly construed the claims by limiting them to a preferred embodiment. In response, T-Mobile argued that “a direct parallel bus interface” was not only the preferred embodiment but the only embodiment disclosed in the ’079 patent specification. As to Inpro’s claim differentiation argument, T-Mobile contended that there is no requirement that different claims must always be of different scope.

The Federal Circuit held that the district court’s interpretation that the term requires direct parallel connection is correct. In so doing, the Court first turned to the specification and noted that the only host interface described is a direct parallel bus interface. Moreover, the specification emphasizes the importance of such an interface in solving the problems with serial interfaces. In fact, the specification expressly touted the benefits of a direct parallel bus interface. Turning to the prosecution history, the Court noted that usage of the term “host interface” during the prosecution of related applications was consistent with the district court’s claim construction. Accordingly, based on the specification and the prosecution history, the Court agreed with the district court’s construction.

Additionally, Inpro argued that the district court improperly refused to consider expert testimony and extrinsic evidence in its claim construction. The Federal Circuit dismissed this argument, noting that a district court has sound discretion in determining if there is a need for and the use of expert testimony.

Thus, in view of Inpro’s stipulation that it could not prevail under the district court’s constructionof “host interface” and the Federal Circuit’s affirmance of the construction, the Court affirmed the district court’s judgment of noninfringement and did not consider the remaining disputed claim terms.

Judge Newman, who authored the majority opinion, also included additional views. While Judge Newman agreed that the Court’s construction of “host interface” was dispositive, she argued that the Court should have construed all three disputed terms. In her view, the Court had anobligation to review the construction of the three appealed terms because “silence leave[s] a cloud of uncertainty on the patent, its scope, and its validity.”