In the Williamson v. Citrix opinion issued June 16, 2015, the Court of Appeals for the Federal Circuit has withdrawn their earlier opinion in the case and abandoned the heightened burden that had been established with regard to assessing whether a claim limitation is a means-plus-function term subject to 35 U.S.C § 112, paragraph 6.

At issue in Williamson v. Citrix was the meaning under § 112, paragraph 6 of the term “module” of the “distributed learning control module” limitation in the claim. 

Although there is a presumption that the presence (or absence) of the phrase “means for” invokes (or does not invoke) § 112, paragraph 6, such a presumption is rebuttable.  As such, in determining the meaning of “module” in Williamson v. Citrix, the Federal Circuit, citing Greenberg v. Ethicon Endo-Surgery, Inc., noted that the essential inquiry is whether the words of the claim are understood by persons of ordinary skill in the art to have sufficiently definite meaning as the name for structure. 

The Federal Circuit also noted that a string of cases after Greenberg had progressively raised the inquiry in Greenberg.  For example, in Lighting World, Inc. v Birchwood Lighting, Inc., a higher bar than the standard in Greenberg was applied.  Namely, in Lighting World, the presumption flowing from the absence of the term “means” was indicated as being a presumption that is a “strong one that is not readily overcome.” 

In Flo Healthcare Solutions, LLC v. Kappos, the bar set in Lighting World (and reiterated in Inventio AG v. ThyssenKrupp Elevator Americas Corp.) was raised even further to “[w]hen the claim drafter has not signaled his intent to invoke § 112, paragraph 6 by using the term ‘means,’ we are unwilling to apply that provision without a showing that the limitation essentially is devoid of anything that can be construed as structure.”

With the new Williamson v. Citrix opinion, the Federal Circuit has overturned the above-noted string of cases, holding that the heightened bar resulting from these cases is “unjustified.”  For example, in the opinion, the Federal Circuit noted that the “strong” presumption from Lighting World has resulted in a proliferation of functional claiming untethered to §112, paragraph 6, and free of the strictures set forth in the statute.  

Thus, the Federal Circuit in Williamson v. Citrix has abandoned characterizing as “strong” the presumption that a limitation lacking the word “means” is not subject to §112, paragraph 6, holding such characterization to be “unwarranted.”  The Federal Circuit also overruled the strict requirement of “a showing that the limitation essentially is devoid of anything that can be construed as structure.”

Therefore, the current standard, which reverts back to the pre-Lighting World standard, is whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure.  If the words of the claim do not meet this standard, §112, paragraph 6 applies.

With regard to the particulars in Williamson v. Citrix, the term “module” was held to connote a generic “black box” for performing the recited computer-implemented functions, and was construed as a well-known nonce word operating as a substitute for “means” in the context of §112, paragraph 6.  The Federal Circuit indicated that such nonce words reflect nothing more than verbal constructs tantamount to using the word “means,” and include, but are not limited to, words such as “module,” “mechanism,” “element,” and “device.”  In this case, the term “module” was construed simply as a generic description for software or hardware that performs a specified function, and therefore the presumption against means-plus-function claiming was rebutted. 

Because §112, paragraph 6 was held to apply to the term “module,” the specification of the US 6,155,840 patent (the “‘840 patent”) in Williamson v. Citrix was then analyzed to determine whether or not the specification imparted any structural significance to the term “module.”

Because the specification of the ‘840 patent failed to describe how the “distributed learning control module,” by its interaction with the other components in the distributed learning control server, was to be understood as the name for structure, the judgment by the District Court that claims 8-16 were invalid for indefiniteness under 35 U.S.C. §112, paragraph 2 was affirmed by the Federal Circuit.

The takeaway from the new Williamson v. Citrix opinion is to make sure that the specification includes sufficient corresponding structure for all claim elements.