The Federal Circuit, sitting en banc, has broadened the circumstances in which claims limitations will be deemed means-plus-function limitations.

Under 35 USC 112(f)):

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. (Emphasis added.)

Software-related patents, in particular, tend to have very broad functional claiming. The new decision limits such broad claims.

The patent at issue in the case describes methods and systems for creating a virtual classroom for geographically dispersed students, via a computer network.

Claim 8 of the patent sets forth:

a distributed learning control module for receiving communications transmitted between the presenter and the audience member computer systems and for relaying the communications to an intended receiving computer system and for coordinating the operation of the streaming data module. (Emphasis added.)

A district court concluded that that this claim “failed to disclose the necessary algorithms for performing all of the claimed functions” and thus that the claim and its dependent claims were invalid as indefinite.

“Nonce” Words

The Federal Circuit affirmed this part of the lower court’s ruling, noting that:

“Module” is a well-known nonce word that can operate as a substitute for “means” in the context of § 112, para. 6. As the district court found, “‘module’ is simply a generic description for software or hardware that performs a specified function.” [cite] Generic terms such as “mechanism,” “element,” “device,” and other nonce words that reflect nothing more than verbal constructs may be used in a claim in a manner that is tantamount to using the word “means” because they “typically do not connote sufficiently definite structure”…

The case is Richard A. Williamson v. Citrix Online, LLC.


This decision may be considered generally unfavorable to software-related patents and will change the way that they are drafted in the future. There is a greater risk now that claim terms that include  “nonce” words, such as “module,” will be found indefinite.

According to Judge Newman’s dissent in the case,

The result [of the decision] is clear: additional uncertainty of the patent grant, confusion in its interpretation, invitation to litigation, and disincentive to patent-based innovation.

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Leech Tishman’s Intellectual Property Group is based in Pasadena, California with a team of highly-regarded legal professionals with prosecution and litigation expertise in the fields of patent, trademark, copyright, and trade secrets.

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Photo Attribution: “ZSpace 200 with students” by ZSpace, Inc. – Own work. Licensed under CC BY-SA 4.0 via Wikimedia Commons.

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