USA: ArcelorMittal France v. AK Steel Corp, United States Court of Appeals, Federal Circuit, No. 2014-1191, 12 May 2015

In light of a binding prior Federal Circuit decision narrowly construing a key claim term in a patent relating to type of mechanically-resistant steel sheet, the federal district court in Wilmington, Delaware, properly invalidated the first 23 claims of a reissue patent as impermissibly broader than the original claims, but the court erred in invalidating two newly added claims because they did not exceed the scope of the original claims, the U.S. Court of Appeals for the Federal Circuit has determined (ArcelorMittal France v. AK Steel Corp., May 12, 2015, Hughes, T.). The case was remanded to the district court for a decision on the merits regarding the two valid claims.

A full summary of this case has been published on Kluwer IP Law.