CBT Flint Partners, LLC v. Return Path, Inc., and Cisco Ironport Systems, LLC

When an obvious error is present, a court must consider reasonable interpretations of a patent claim from the point of view of one skilled in the art.

Opinion (Lourie): The United States District Court for the Northern District of Georgia granted summary judgment of invalidity of U.S. Patent 6,587,550 ("'550 patent"), owned by CBT Flint Partners, LLC ("CBT"). The district court found Claim 13 of the '550 patent indefinite and, thus, held the '550 patent invalid and awarded costs to Cisco Ironport Systems, LLC and Return Path, Inc., (collectively "Cisco"). Claim 13 contained an "obvious and correctable error" which the district court refused to correct. If a district court "determines that a claim is not 'amendable to construction,' then the claim is invalid as indefinite under 35 U.S.C § 112." However, "in a patent infringement suit, a district court may correct an obvious error in a patent claim." Further, "the enactment of 35 U.S.C §§ 254 and 255 did not . . . deny authority to the district courts to correct a claim in appropriate circumstances." When correcting a claim, a court must "consider how a potential correction would impact the scope of a claim and if the inventor is entitled to the resulting claim scope based on the written description of the patent." All three reasonable alternatives considered by the district court would have resulted in the same claim scope, thus, the Court of Appeals for the Federal Circuit REVERSED the district court's summary judgment of invalidity, VACATED the award of costs to Cisco, and REMANDED the case for further proceedings.