In Williamson v. Citrix,[1] the Federal Circuit overruled its own precedent that there is a “strong” presumption that claim limitations that do not use the term “means” are not means-plus-function limitations. This change has been decried by practitioners who purposefully avoid the word “means” in order to avoid means-plus-function treatment of their functionally claimed elements.

What do you accomplish by avoiding means-plus-function treatment? Under 35 U.S.C. 112(f),[2] means-plus-function elements are “construed to cover the corresponding structure . . . described in the specification and equivalents thereof.” Is it reasonable to expect that a “means”-less functional element would be construed to be broader than provided in §112(f)? No. Claims are, and always have been, limited the scope of the written description and the enabling disclosure in the specification. There is a risk that by not limiting a claim to what is disclosed in the specification and equivalents thereto, the claim will be found invalid.

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