PatentNext Summary: As a general rule, software-related patents should include an algorithm. An algorithm provides support for a software-related patent in a variety of ways, one of which is to provide support for a claim determined to be a “means-plus-function” (MPF) term pursuant to 35 U.S.C. § 112(f). Without such support, an MPF term can be held invalid pursuant to 35 U.S.C. § 112(b).

The below article provides additional details. This article forms the first part of a multi-part series.


Software inventions typically claim software-related elements such as computing instructions, module(s), package(s), component(s), or the like. These terms typically represent the source code or object code of the invention. However, when functional language follows these software-related terms, a risk arises where a court may construe such terms as means-plus-function (MPF) terms (even where the claim does not recite express “means for” or “step for”  language per 35 U.S.C. § 112(f)). Once construed as an MPF term, a court will look to the patent’s specification to determine whether any “structure” (computer hardware) implements the claimed function recited by the MPF term. If the determined structure comprises only general-purpose computer components (such as a general-purpose “processor”) then Federal Circuit law requires that the specification provide an “algorithm” corresponding to the function. If no such “algorithm” can be found, the court can hold the claims invalid as indefinite pursuant to 35 U.S.C. § 112(b)

For example, in Rain Computing, Inc. v. Samsung Electronics Co., Ltd, the Federal Circuit found that the claim term “user identification module” was an MPF term that lacked a corresponding algorithm in the patent specification, and thus was invalid as indefinite.  Case 2020-1646 (Fed. Cir., March 2, 2021). 

Specifically, in Rain Computing, the claim-at-issue recited a “method for providing software applications through a computer network based on user demands” and included the “user identification module” element:

sending, to the user, a user identification module configured to control access of said one or more software application packages, and coupling the user identification module to a client terminal device of the user;

First, the court determined whether the element was an MPF term.  Because the term lacked any commonly understood meaning to those of ordinary skill in the art, and because neither the specification nor the claim itself provided any structural meaning, the court found the “user identification module” to be an MPF term.

Next, the Rain Computing court searched the specification for structure (i.e., computer hardware) that performed the function of the “user identification module” (i.e., the function being “to control access to one or more software application packages to which the user has a subscription,as expressly recited by the claim). The Federal Circuit found that specification recited only general-purpose computer hardware as a structure for performing the given function. Such structure included “computer-readable media or storage devices,” such as “SIM card, IC card, a flash memory drive, memory card, a CD-ROM, and the like.” 

However, because such structure amounted to mere “general-purpose” computer components (and not special purpose computer components) an algorithm was required to transform the general-purpose computer components into a special purpose computer: 

For means-plus-function claims “in which the disclosed structure is a computer, or microprocessor, programmed to carry out an algorithm,” we have held that “the disclosed structure is not the general-purpose computer, but rather the special purpose computer programmed to perform the disclosed algorithm.

Slip op. at 7 (citing WMS Gaming, Inc. v. Int’l Game Tech., 184 F.3d 1339, 1349 (Fed. Cir. 1999)

And because the specification of the patent-at-issue failed to disclose an algorithm to perform the function of the “user identification moduleon the general-purpose computer components, the Federal Circuit found the patent claim indefinite. General-purpose computers cannot provide structure for MPF claim elements without an algorithm:

Under these circumstances, where a general-purpose computer is the corresponding structure and it is not capable of performing the controlling access function absent specialized software, an algorithm is required.

Slip op. at 9.

Moreover, nothing in the claim language or the written description provided an algorithm to achieve the “control access” function of the “user identification module.” Slip op. At 9. In fact, the specification did not even mention the term “user identification module” a single time.

Because no algorithm could be found, the Federal Circuit held that the term “user identification module” lacked sufficient structure, rendering the claims indefinite, and thus, invalid pursuant to 35 U.S.C. § 112(b).

The  Rain Computing case demonstrates that, as a general rule, software-related patents should include an algorithm. Had an algorithm been included, the patent-at-issue may have been found definite and, therefore, valid.

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