PTAB Claim Construction May Be Binding In Later Litigation

In 2016, the Federal Circuit expressed doubt that claim constructions from the PTAB could give rise to estoppel in later litigation because "the [PTAB] applies the broadest reasonable construction of the claims while the district courts apply a different standard of claim construction as explored in Phillips." SkyHawke Techs., LLC v. Deca Int'l Corp., 828 F.3d 1373, 1376 (Fed. Cir. 2016). But that distinction does not apply if the PTAB applies the Phillips standard to construe claim terms, as one district court explained in finding that it was collaterally estopped from apply a claim construct different from that applied by the PTAB. Regents of the Univ. of Minn. v. LSI Corp., No. 5:18-cv-00821-EJD, 2023 WL 5520958 (N.D. Cal. Aug. 25, 2023). In that case, the University of Minnesota sued LSI for infringement of its patent covering certain digital storage systems. LSI sought inter partes review, and the district court suit was stayed. The PTAB found