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The Federal Circuit affirmed the district court’s holding that reissue claims that were broader than the claims of the original patent, as construed by the court, were invalid for being filed more than two years after issuance of the patent.  In a prior proceeding, the district court had construed the claim term “a very high mechanical resistance” as being limited to steel with a tensile strength greater than 1500 MPa, which was affirmed by the Federal Circuit.  During reissue proceedings, the patentee added a dependent claim which limited the steel to only a tensile strength of 1000 MPa, which had the effect of broadening the sole independent claim, which required the “very high mechanical resistance” limitation that the district court had previously construed.  Later, after amending its complaint to include the reissue patent, the district court held that the independent claim (and all dependent claims) were invalid as being impermissibly broadened more than two years after issuance of the original patent. 

On appeal, the patentee argued that the fact that the PTO issued the claims demonstrates that the PTO construed the phrase “very high mechanical resistance” to be broader than the district court’s construction.  The Federal Circuit rejected this argument because, under the law-of-the-case doctrine and the mandate doctrine, a court may only deviate from a decision in a prior appeal if “extraordinary circumstances” exist.  Here, the patentee argued that the PTO’s decision to allow the new dependent reissue claim is “new evidence,” which shows that the PTO construed the claim term more broadly than the district court and Federal Circuit had.  The court, however, held that the reissue claim itself could not be used to redefine the scope of the original claim, as this comparison would render Section 251 (prohibiting broadening reissue claims) meaningless. 

As to additional dependent claims that had been added during reissue, which required a tensile strength greater than 1500 MPa, the court reversed the district court’s decision to invalidate those claims.  These claims were of the same scope as the claims of the original patent, as construed, and therefore they were not broadened and are therefore valid.  

ArcelorMittal France v. AK Steel Corp., Case No. 2014-1189 (May 12, 2015); Opinion by: Hughes, joined by Dyk and Wallach; Appealed From: District Court for the District of Delaware, Robinson, J.  Read the full opinion here.

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