Means-Plus-Function Patent Claims: Treatment in Prosecution, Litigation, and Post-Grant Proceedings

Description

Section 112(f) reads: "An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof."

Section 112(f) provides a statutory tool allowing the patent drafter to write claims reciting a function and refer to the specification for details of the structures, materials, and acts associated with that claimed function. While having a claim construed as a means-plus-function claim may mean a narrower construction (since the patent owner is limited to the structure disclosed in the specification "and equivalents thereof"), the claim format may be useful when the subject matter claimed is best described functionally.

Nearly every technological field uses means-plus-function claiming. Practitioners in all technologies should consider means-plus-function claims with their built-in literal equivalents as a claiming alternative.

As Ms. Hooson, Dr. Gao, and Mr. Irving will emphasize, the perceived “narrowness” of means-plus-function claims can be advantages in the life sciences and particularly for pharmaceutical claims. Mr. Gutowski will be providing his analysis of means-plus-function claims in the mechanical, computer, and electrical fields.

As will be revealed, counsel should weigh the pros and cons of such claims as they are limited to the subject matter described in the specification as being linked to the materials, structures, and uses for accomplishing the function recited in the claims and statutory, i.e., literal, equivalents thereof. Omitting the term "means" apparently no longer provides a "strong" presumption that 112(f) is not applicable, according to the en banc portion of Williamson v. Citrix Online L.L.C. (Fed. Cir. 2015). And the MPEP expressly condones the use of nonce words (those coined for special use), such as "components for," as a placeholder for the "means for."

There is also a danger that failure to identify the structure, materials, or acts corresponding to the claimed function under a 112(f) scenario may result in an invalidated indefinite claim under 112(b).

Listen as our authoritative panel examines how both means-plus-function and functional claims are used in different fields, as mentioned above, and their future potential.