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IP Alert: Knowledge Within the Art Does Not Save Means-Plus-Function Claim Term Lacking Corresponding Structure

February 19, 2021

On February 12, in Synchronoss Technologies, Inc. v. Dropbox, Inc., the Federal Circuit affirmed that certain of Synchronoss’s claims were invalid for indefiniteness, since the claims included a means-plus-function claim term that did not have adequate structural support in the specification. The Federal Circuit held the claims invalid, despite testimony from Dropbox’s expert indicating that one having skill in the art would have known of structure to carry out the function of the claim term.

Synchronoss sued Dropbox, accusing it of infringing three patents on technology for synchronizing data across multiple devices. The district court’s claim construction order held all claims of one of the patents invalid for indefiniteness, agreeing with Dropbox that the specification did not support means-plus-function claim language.

The Federal Circuit affirmed the district court. Because the specification failed to detail what a user identifier module consists of or how it operates, the specification lacked structural support corresponding to the claim term “user identifier module.” The Federal Circuit further credited the testimony of Dropbox’s expert, Dr. Freedman, who opined that the “user identifier module” in Synchronoss’s claims would be understood by persons having ordinary skill in the art as a functional term that does not impart any particular structure. Dr. Freedman also testified that ordinarily skilled persons would understand “dozens of discrete ways” to implement the functional claim terms, and that the specification failed to describe any specific structure for carrying out the respective functions.

Synchronoss did not offer any contrary expert testimony, but instead relied on the list of structures that Dr. Freedman provided as evidence that a person of ordinary skill would have understood structure that corresponds to the functional “user identifier module,” without the structure being detailed in the specification. The Federal Circuit rejected Synchronoss’s argument, stating:

It is not enough that a means-plus-function claim term correspond to every known way of achieving the claimed function; instead, the term must correspond to “adequate” structure in the specification that a person of ordinary skill in the art would be able to recognize and associate with the corresponding function in the claim.

Finding no adequate structure in the specification corresponding to the “user identifier module,” the Federal Circuit held the term indefinite and the associated claims invalid.

This case illustrates the importance of providing adequate structural support for means-plus-function claim terms in the specification. Regardless of the knowledge of a person having skill in the art, a means-plus-function claim term is still indefinite if the specification does not include “adequate” corresponding structure.

For more information on this ruling, please contact Fitch Even attorney Zachary Van Engen, author of this alert.

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