This case addresses the “skilled and diligent searcher” standard used for establishing Inter Partes Review (“IPR”) estoppel (or lack thereof). In particular, this case establishes: (1) which party bears the burden of proof regarding whether a “skilled and diligent searcher” could have reasonably been expected to discover prior art such that failure to include it in an IPR petition estops the petitioner from raising it in other civil actions under 35 U.S.C. § 315(e)(2); and (2) the “skilled and diligent searcher” inquiry itself with respect to what a skilled and diligent searcher reasonably would have been expected to discover.

Continue Reading Ironburg Inventions Ltd. v. Valve Corp. 21-2296 (Fed. Cir. Apr. 3, 2023)