PTAB Adopts Nautilus Indefiniteness Standard

In post-grant proceedings since 2018, the PTAB has applied the same claim construction standard as used in district court; a recent Memorandum confirms the PTAB will likewise apply the same standard that district courts use for evaluating indefiniteness of patent claims.

Determining whether a patent claim is indefinite pursuant to 35 U.S.C. § 112 is generally considered a matter of claim construction.  Until 2018, the PTAB had interpreted claims in AIA post-grant proceedings pursuant to the "broadest reasonable interpretation," or the standard employed by patent examiners during pre-issuance examination of patent claims.  District courts, however, interpret claims according to the standard articulated in the Federal Circuit's en banc decision in Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc).