Means-Plus-Function: Identification of Function and Corresponding Structure Reviewed De Novo

JVW Enterprises v. Interact Accessories (Fed. Cir. 2005).

In a case involving a video game controller, the appeals court reversed-in-part, finding that the lower court had misconstrued the means-plus-function limitation.

De Novo: Like other claim construction, the interpretation of means-plus-function language is reviewed de novo.  More particularly, identification of the function and corresponding structure is reviewed de novo.

In this case, the CAFC found that the district court’s opinion “confuses function with structure.”  According to the appellate panel, “function must be determined before corresponding structure can be identified.” 

Function as claimed: The function of a means-plus-function claim is found in the claim language.  In this case, the district court erred in interpreting unclaimed functions into the claims. 

Structure as described: The corresponding structure of a claimed function must be found in the specification — and must be clearly associated with performance of the function.

The CAFC reversed and remanded based on consequences of the err in claim construction.