Federal Circuit Modifies Means-Plus-Function Presumption
June 23, 2015

On June 16, 2015 the Federal Circuit decided en banc to overturn a panel decision of the Federal Circuit that held the term “module” in the context of a computer software patent did not invoke means-plus-function claiming under 35 U.S.C. § 112, para. 6 and, consequently, was not indefinite for failure to disclose corresponding structure in the specification, i.e., an algorithm. Williamson. v. Citrix Online, LLC, 2013-1130 (Fed. Cir. 2015). The en banc decision, however, went further than simply overturning the previous panel decision. In holding that the claims at issue did invoke mean-plus-function interpretation and consequently were indefinite, the en banc decision overturned more than a decade’s worth of case law that held there exists a strong presumption that claims not employing the term “means” did not invoke the provisions of 35 U.S.C. § 112, para. 6. The presumption still exists but is no longer “strong.”

Section 112, para. 6 (now § 112, para. f as re-designated in the American Invents Act) authorized claims in the form of “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.”  

The patent in Williamson disclosed and claimed methods for distributed learning that employ industry standard hardware and software to generate a “virtual classroom” permitting interaction between a presenter and remote audience members. The patent included claims reciting, in part, a “distributed learning control module” that performed three functions: (1) receiving communications transmitted between the presenter and the audience member computer systems; (2) relaying the communications to an intended receiving computer system; and (3) coordinating the operation of the streaming data module.  

The majority held that the term “module” is merely a nonce word, i.e., a construction that by itself signifies nothing because one of skill in the art would not understand “module” to “have a sufficiently definite meaning as the name for structure.”  While a claim that lacks the term “means” still benefits from the presumption that the claim does not invoke mean-plus-function limitations, this presumption is no longer “strong.”  As before, a challenger can rebut the presumption by showing that the claim fails to recite “sufficiently definite structure” or else recites “function without reciting sufficient structure for performing that function.” The majority held that the patent failed to disclose sufficient structure in the specification and, consequently, held the relevant claims indefinite.

The Williamson decision affects the interpretation of many software related patents and claims that employ functional limitations and arguably do not disclose an algorithm or flow charts of “sufficiently definite structure.”  The majority decision explained that, like “module,” other “[g]eneric terms such as “mechanism,” “element,” “device,” and other nonce words that reflect nothing more than verbal constructs may be . . . tantamount to using the word “means” because they “typically do not connote sufficiently definite structure” and therefore may invoke § 112, para. 6.”  Williamson will likely affect all technologies and all patents that employ claims with functional limitations.

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