Request to stay injunction pending appeal may also be considered notice of appeal; estoppel bars DOEFebruary 12, 2008

In a decision yesterday, the Federal Circuit reversed a jury's verdict of infringement under the doctrine of equivalents. The court had previously vacated-in-part and reversed-in-part the district court's earlier summary judgment of infringement, the result of which was the jury trial conducted by the district court. The combination of the Federal Circuit's mandate in the earlier appeal and application of prosecution history estoppel precluded the jury's finding of infringement.

On a jurisdicitonal issue, the court also held that the appellee's request to stay enforcement of the injunction pending appeal was sufficient to serve as a notice of appeal under Rule 3, even though no separate notice was filed within the timeframe required by Rule 4.

International Rectifier (IR) asserted IXYS infringed claims of three of its patents, the '699, '725, and '767 patents. The three patents disclose metal-oxide-semiconductor field effect transistors (MOSFETs). The transistors are manufactured by "doping the surface of a silicon wafer with a pattern of impurities so as to create multiple regions with different electrical properties."The district court had previously issued summary judgment rulings holding that IXYS's devices infringed asserted claims of the relevant patents. The Federal Circuit, on the prior appeal, issued revised interpretations of the claim terms defined by the district court. Regarding the claims of the '699 patent that require a "'lightly doped' region that is 'adjoining' a 'region of opposite conductivity type,'" the Federal Circuit held that "there can be no infringement" and remanded "with instructions to enter a judgment of non-infringement of these claims in favor of IXYS." Additional claims, with substantially similar language in all three patents, require both a "first base region" of "polygonal" shape and a "first source region" "having the shape of an annular ring." On the previous appeal, the court found fact issues existed under the proper construction of these limitations, and remanded for further proceedings in light of the corrected construction.

On remand, the district court concluded that the Federal Circuit's ruling with respect to the '699 "adjoining" claim term was relevant to literal infringement only, and allowed the issue of infringement under the doctrine of equivalents to be tried to a jury. The jury found that the accused devices infringed the '699 patent's "adjoining" claims. With regard to the "annular" and "polygonal" limitations, the court held that because IXYS did not list the "annular" term as disputed for the '699 patent on the claim chart required by the local rules, it served as an admission that its products met that claim limitation, even though it contested the same term in the other patents. The jury ultimately concluded that IXYS infringed the "polygonal" limitation under the doctrine of equivalents, but that the devices did not have "annular" source regions. So, the district court entered judgment of infringement for the '699 patent (based on the "admission" and the jury's findings), and entered a permanent injunction. Because the jury found that IXYS's devices did not posses "annular source regions," it found that IXYS did not infringe the '725 and '767 patents. IXYS appealed the finding of infringement and permanent injunction.The Federal Circuit initially considered whether it had appellate jurisdiction over the case. IXYS did not file a document styled as a notice of appeal, but did file with the district court a motion to stay the permanent injunction pending appeal. The Federal Circuit concluded that this document qualified as a notice of appeal. Citing the Supreme Court case Smith v. Barry, the Federal Circuit noted that an adequate notice of appeal must: "(A) specify the party or parties taking the appeal . . . ; (B) designate the judgment, order, or part thereof being appealed; and (C) name the court to which the appeal is taken." These requirements were met here, as the request to stay the injunction pending appeal stated:

[(A)] [D]efendant IXYS Corporation (‘IXYS’) will, and hereby does, move the Court for an order staying the execution of [(B)] its September 14, 2006, Final Judgment and enforcement of the permanent injunction entered on the same date pending resolution of IXYS’s appeal to the [(C)] Federal Circuit Court of Appeals.

As a result, the request to stay enforcement of the injunction was sufficient to serve as a notice of appeal under Rule 3, and the court had jurisdiction over the appeal.Turning to the issue of infringement, IXYS argued that the "adjoining" limitation was added to the claims in order to overcome § 112 rejections during prosecution of the '699 patent, and as a result, prosecution history estoppel precluded the jury's finding of infringement under the doctrine of equivalents. IR argued that the claim at issue had actually been broadened, so prosecution history estoppel did not apply, and alternatively, even if the claim was narrowed, that the amendment was only tangentially related to the equivalent in question. The Federal Circuit rejected IR's arguments. First, the court noted that while the claim as a whole may have been broadened, the limitation at issue was narrowed via the amendment, and as a result, the Festo presumption of prosecution history estoppel applied. Further, the court held the amendment was not tangential to the asserted equivalent, stating: "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." As a result, prosecution history estoppel barred IR from asserting infringement of the "adjoining" limitation under the doctrine of equivalents, and the court reversed the district court's entry of judgment of infringement of the "adjoining" claims.Turning to the "annular" and "polygonal" claims, the court held that on the prior appeal, IR had offered, as an alternative basis to affirm, IXYS's "admission" regarding the "annular limitation." The Federal Circuit rejected this argument, and the court therefore held that the district court was precluded from treating the limitation as admitted on remand. To do otherwise would be contrary to the court's mandate in the earlier appeal. As a result, the jury's findings regarding the "annular" limitation in the other two patents also applied to the '699 patent, and the finding of infringement was reversed as to those claims of the '699 patent as well.To read the full decision in Int'l Rectifier Corp. v. IXYS Corp., click here.

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