A Means-Plus-Function Trap—Presumption Fails To Save Functional Claims Lacking Structural Antecedent

. . . "This is the epitome of functional claiming: a black box that captures any and all structures that fulfill the function, just as if 'means' was used."

In WSOU Investments LLC v. Google LLC, No. 2022-1064 (Fed. Cir. Oct. 6, 2023), the United States Court of Appeals for the Federal Circuit ("Federal Circuit") rejected an appeal by WSOU Investments LLC ("WSOU") from a final judgment of invalidity of its U.S. Patent 8,751,585 ("the '585 patent") by the United States District Court for the Western District of Texas. The district court had determined that (1) the asserted claims in the patent are means-plus-function claims even though the claims do not expressly include the word "means" and (2) the claims are indefinite because certain claim limitations lacked sufficient corresponding structure in the patent's specification even though the term "processor" is recited as a claim limitation.