Denial of Preliminary Injunction Improper Because Plaintiff Did in Fact Make a Proper Claim of Priority to Provisional Application

E.I. Du Pont De Nemours And Company, v. Macdermid Printing Solutions, L.L.C., [2007-1568] (May 14, 2008) [MICHEL, Prost, Pogue] The Federal Circuit held that the district court abused its discretion in finding that a substantial question as to validity existed because of uncertainty regarding the priority date and vacated and remanded the denial of a preliminary injunction for the district court to consider in light of the correct priority date.
BRIEF: Because of a Patent Office error the claim for priority to a non-provisional application was omitted from the face of the patent in suit, although it was indicated on a certificate of correction. At the preliminary injunction hearing, duPont appeared to concede that the invention was on sale prior to the critical date, but later corrected this with information about the claim of priority to the provisional application. DuPont submitted a letter in response, stating that it had promptly notified the court of its discovery that the patent was entitled to an earlier effective filing date, that defendant admitted it had been aware of the provisional application, that its non-provisional application had properly claimed priority to the provisional application, and finally that it did not make binding judicial admissions. The sole issue raised by DuPont is whether the district court correctly held that MacDermid raised a substantial question of validity based on the uncertainty as to whether the non-provisional application was entitled to claim priority to the provisional application. The Federal Circuit held that this conclusion was an abuse of discretion because based on the undisputed facts contained in the prosecution history, the non-provisional application was entitled to the filing date of the provisional application as a matter of law.