In determining whether a claim element invoked 35 USC § 112, ¶ 6, the US Court of Appeals for the Federal Circuit concluded that “module” was a nonce term and required sufficient corresponding structure in the patent specification to avoid indefiniteness under 35 USC § 112, ¶ 2. Rain Computing, Inc. v. Samsung Electronics Co., Ltd., Case Nos. 20-1646, -1656 (Fed. Cir. Mar. 2, 2021) (Moore, J.)

Rain sued Samsung for infringement of a patent directed to a method for delivering software application packages to user terminals over a network. The claims at issue included an element that recited a “user identification module configured to control access [to] software application packages.” The district court determined that the “user identification module” was a means-plus-function term subject to 35 USC § 112, ¶ 6, but that the specification disclosed sufficient corresponding structure such that the term was not indefinite. Rain appealed the judgment of non-infringement.

Reviewing de novo, the Federal Circuit first addressed whether the claim language invoked § 112, ¶ 6. While there is a rebuttable presumption that ¶ 6 does not apply to claims lacking “means” language, the Court noted that “module” does not provide any indication of structure and is a well-known substitute for “means.” No other claim language, including the “user identification” prefix, imparted any structure onto the term. For purposes of claim construction, the specification also did not impart any structure to the claimed user identification module. Rain argued that amendments and examiner arguments during prosecution were proof of sufficient structure, and that, as the examiner noted, a means-plus-function term cannot be nested within a method claim. The Federal Circuit disagreed, noting that the examiner’s statement that a means-plus-function claim element cannot be nested within a method step was simply incorrect as a matter of law. Thus the Court found that “user identification module” was a means-plus-function claim term.

Citing to its 2015 en banc ruling in Williamson v. Citrix Online, the Court turned to the term’s construction under §112, ¶ 6, applying the same two-step process it used just a few weeks earlier in Synchronoss Technologies v. Dropbox. In the first step, the Court simply used the district court’s undisputed finding that the function was “to control access to . . . software packages to which the user has a subscription.” In the second step, the Court attempted to identify corresponding structure in the specification. Here the Court noted that structure in a specification corresponds only if there is a clear link or association, and that the specification must also disclose an actual algorithm when the function is performed by a general-purpose computer.

The Federal Circuit concluded that the district court erred in finding that the disclosure of a storage device provided sufficient structure, explaining that such devices are nothing more than general purpose computers not capable of performing the access control function without specialized software—an algorithm. Rain’s patent specification disclosed no such algorithm, without which the “user identification module” lacked sufficient structure. Thus the Court found the claim element indefinite.