Form vs. Substance In Means-Plus-Function Analysis

Section 112(f) of the patent statute allows a patentee to define a structural claim element in terms of its function alone, i.e., "as a means ... for performing a specified function without the recital of structure ... in support thereof."^[1] In that case, the claim is construed "to cover the corresponding structure ... described in the specification and equivalents thereof."^[2] However, following Federal Circuit decisions from the 1980s, traditional "means-plus-function" claim drafting has been steadily declining.^[3] The number of issued patents including "means for" language has dropped from about 60 percent in the 1980s to less than 10 percent today.^[4]

^{[1] 35 U.S.C. § 112(f).}

^{[2] Id. The statute also allows drafting of "step-plus-function" limitations, which are outside the scope of this article.}

^{[3] B.K. Wheelock et al., 35 U.S.C. 112, ¶ 6 - Means for Better Patent Protection, 47 St. Louis L.J. 1065, 1065–66 (2003).}

^{[4] Id.; D. Crouch, Functional Claim Language in Issued Patents, Patently-O (Jan. 23, 2014), at http://patentlyo.com/patent/2014/01/functional-language-patents.html.}

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Originally published by Law360

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