Federal Circuit Revisits And Recasts Means-Plus-Function Claim Interpretation

An en banc decision from the Federal Circuit last week overruled a line of cases governing the interpretation of functional claim language, calling into question how courts, the PTO, and industry will treat such language in the future. 

In Williamson v. Citrix Online, LLC, et al., No. 2013-1130 (Fed. Cir. June 16, 2015) (en banc as to Part II.C.1), the Federal Circuit struck down the "strong," "not readily overcome" presumption that a claim element lacking the word "means" should not be interpreted as a means-plus-function element governed by § 112, para. 6 (now § 112(f)).  In its place, the Court appeared to revert to its pre-2004 precedent which applied only a simple presumption.  See, e.g., Personalized Media Communications, LLC v. International Trade Commission, 161 F.3d 696, 703–04 (Fed. Cir. 1998) (citing cases).  The Court articulated the new standard as follows: