Mastermine Software, Inc. v. Microsoft Corp. (Fed. Cir. 2017), as well as several previous cases, have ruled that mixing system and method claims in the same claim can lead to indefiniteness and ultimately invalidity. The reason behind this invalidity ruling is that a potential infringer may not be able to distinguish when he is infringing the claim – when he makes/sells an infringing system or uses the system in an infringing manner? So how do you avoid creating an indefinite claim?
(1) Make sure the apparatus or system performs the function or method steps; (2) Avoid clauses in which a user performs a function or method; and (3) Avoid standalone method steps (not performed by a system element) when the rest of the claim is clearly a system or apparatus claim.
When we at Aurora draft system claims in which components are executing functions or method steps, we use language along the following lines: “wherein the ‘element’ performs a method comprising: steps A, B, C…” This structure should avoid the issues enumerated above. Happy drafting!