Corresponding Structure Snafu: Lack of Algorithm Renders Claims Indefinite


Before Lourie, Dyk, and Moore. Appeal from the United States District Court for the District of Massachusetts.

Summary: The structure for performing a function of a means-plus-function term may not be a general purpose computer without an algorithm for performing the function.

In 2018, Rain Computing, Inc. (“Rain”) filed suit against Samsung Electronics Co. Ltd., Samsung Electronics America, Inc., Samsung Research America, Inc. (collectively “Samsung”) for patent infringement based on Samsung’s provision of software applications through an app store. Specifically, the claims of the patent are directed to delivering software application packages to a client terminal. In February of 2020, the district court issued an order construing various terms including an “executing” term and a “user identification module” term. The district court further determined that the term “user identification module” was a means-plus-function term and was not indefinite. Following that order, the district court entered judgment, based on the parties’ joint stipulation, that the asserted claims were neither infringed nor invalid for indefiniteness. Rain appealed and Samsung cross-appealed.

On appeal, Rain challenged the district court’s construction of the “executing” term and Samsung challenged the district court’s construction of the “user identification module” term. Specifically, Samsung challenged the court’s determination that the “user identification module” term does not render the claims indefinite. Samsung argued that the “user identification module” term lacked specific structure to render the term definite. The Federal Circuit agreed with Samsung’s arguments. First, the Federal Circuit concluded that, the term “user identification module” is a means-plus-function term, noting that “module” is a well-known nonce word that can substitute for “means”, that the term was not commonly understood to connote a particular structure, and that the specification does not impart any structural significance to the term. Having determined that the term was a means-plus-function term, the Federal Circuit next identified the function “to control access to one or more software application packages to which the user has a subscription.” The function was undisputed by both parties. Finally, the Federal Circuit determined that the specification failed to disclose adequate corresponding structure for executing the function of the “user identification module.” The Federal Circuit explained, that where, as was the case here, the corresponding structure is a general computer that is not capable of performing the controlling access function without specialized software, the specification must disclose the algorithm the computer performs to accomplish that function. Because the Federal Circuit concluded that nothing in the claim language or the written description provided an algorithm to execute the function of the “user identification module”, it found the term “user identification module” lacked sufficient structure, rendering the asserted claims indefinite. Accordingly, the Federal Circuit reversed the district court’s judgment that the claims are not invalid as indefinite and dismissed Rain’s appeal as moot.

Editor: Paul Stewart