Adding a Limitation While Removing Others is Still a Narrowing Amendment for Puproses of Prosecution History Estoppel

International Rectifier Corp. v. IXYS Corp., [2007-1063, -1141, -1165] (February 11, 2008) [LINN, Dyk, Prost] The Federal Circuit reversed summary judgment of infringement because infringement as to each asserted claim was foreclosed either by the combination of our mandate in the prior appeal and the jury verdict or by prosecution history estoppel.
SIGNIFICANCE: An amendment that narrows a claim on any way is a narrowing amendment for purposes of prosecution history estoppel
BRIEF: The threshhold question was whether the Federal Circuit had jurisdiction. The Federal Circuit held that a motion to stay the permanent injunction was equivalent to a notice of appeal. With respect to the merits, the Federal Circuit declined to rely on its previous mandate, and reach the question of prosecution history estoppel, which could affect future cases. Prosecution history estoppel limits the broad application of the doctrine of equivalents by barring an equivalents argument for subject matter relinquished when a patent claim is narrowed during prosecution. LOF: The Federal Circuit reviews issues relating to the application of prosecution history estoppel de novo. IXYS argued that IR added the "adjoining" limitation in order to overcome rejections under 35 U.S.C. § 112, paras. 1–2. IR argued that prosecution history estoppel does not apply to its addition of the term “adjoining” because the resulting change in claim language was broadening, not narrowing, and evening if broadening, the amendment in question is only tangentially related to the asserted equivalent. The Federal Circuit found that the amendment was narrowing, because the term excludes structures that might have been covered by the original claim language, and one cannot argue that an amendment is broadening merely because it eliminated some claim limitations. The Federal Circuit also rejected the argument that the amendment was tangential, noting that IR’s decision to claim that structure using the limiting term “adjoining,” whether or not required to overcome the rejection, cannot be described as only tangentially related to the equivalency of a structure with non-adjoining regions. With the amended language, IR recited precisely the structure it disclosed, and thereby overcame the examiner’s § 112 rejection. The Federal Circuit found that the other issues were covered by its previous mandate, and reversed the district court.