Prosecution History Disclaimer and Estoppel Lead To Noninfringement

| Ashley C. MoralesJeremy Anapol


Before Prost, O’Malley, and Stoll. Appeal from the Eastern District of Texas.

Summary: An applicant’s arguments distinguishing prior art during patent prosecution constituted a disclaimer of claim scope and estopped the patentee from relying on the doctrine of equivalents to show infringement.

Traxcell sued Nokia for infringing three patents related to self-optimizing wireless networks. The district court construed the claim term “location” to mean “location that is not merely a position in a grid pattern,” and “first computer” or “computer” to mean a single computer that can perform each function the claims required. Based on these constructions, the district court granted summary judgment of noninfringement. Traxcell appealed.

The Federal Circuit affirmed the construction of “location” because during prosecution the patent applicant had disclaimed “locations in a grid pattern” by distinguishing prior art. The court also affirmed the judgment of noninfringement based on this limitation because Nokia’s unrebutted expert testimony showed that the accused product used only a grid-pattern location.

As to “first computer” and “computer,” the Federal Circuit again found disclaimer based on the applicant’s arguments during prosecution. Further, the court determined that Traxcell had surrendered multiple-computer equivalents during prosecution. And because Traxcell failed to provide evidence of literal infringement under the Federal Circuit’s construction of “computer” and “first computer,” the court affirmed the judgment of noninfringement based on these limitations.

Editor: Paul Stewart