Disagreeing with the district court’s construction of a word appearing in the court’s construction of a claim term, but not present in the patent’s claims, the U.S. Court of Appeals for the Federal Circuit reversed and remanded the district court’s grant of summary judgment of non-infringement. Advanced Fiber Technologies (AFT) Trust v. J&L Fiber Services, Inc., Case No. 11-1243 (Fed. Cir., Apr. 3, 2012) (Lourie, J.)(Dyk, J. dissenting). Specifically, the Federal Circuit found the district court’s reliance on extrinsic evidence that contradicted the specification of the patent to be erroneous and therefore remanded the case for a determination of infringement, based on the Federal Circuit’s construction.

AFT sued J&L Fiber Services for willful infringement of its patent directed to pulp and paper screening devices and methods of using these devices. The district court construed the claim terms “screening medium” and “screening plate” to include the non-claim term “perforated.” A principal focus for the Federal Circuit was whether the definition of a “perforated barrier” was limited to a something “pierced or punctured with holes” or could include a wedgewire screen. A wedgewire screen, a structure included in the accused J&L product, is made by assembling closely spaced parallel wires, not by piercing or puncturing.

The Federal Circuit disagreed with the district court that a “perforated barrier” did not include wedgewire screens, pointing to the fact that wedgewire screens, although not claimed, were expressly included as an embodiment in the specification. Specifically, the Federal Circuit found fault with the district court’s dismissal of the wedgewire embodiment set forth in the specification simply because it was just one sentence, pointing to the maxim that brevity in a patent disclosure should generally be applauded. Furthermore, the Federal Circuit found the district court’s reliance on extrinsic evidence to exclude wedgewire screens from the claim scope to be erroneous.

As for the district court summary judgment dismissal of AFT’s claim of willful infringement, the Federal Circuit noted significant doubt as to the patent’s validity given J&L’s compelling non-infringement and invalidity arguments, a compelling prior art rejection made during the prosecution of the reissue, and the fact that the meaning of some key claim terms in the original patent only became clear via AFT’s arguments during reissue prosecution. The Court therefore affirmed the district court dismissal of the willfulness claim.

In dissent, Judge Dyk while agreeing with the majority on the issue of willfulness, disagreed with its construction of “perforated” and therefore its decision to set aside the judgment on non-infringement. In Dyk’s view, arguments made by AFT during the prosecution of the reissue regarding the definition of perforated plate is intrinsic evidence, that considered with the language of the claims themselves, required exclusion of wedgewire screens from the proper claim scope.