III
Aristocrat’s principal contention is that the district court was wrong to hold that the patent’s disclosure of a general purpose, programmable microprocessor was not a sufficient disclosure of structure to satisfy section 112 paragraph 6. In particular, Aristocrat argues that computer-implemented means-plus-function claims do not require disclosure of a corresponding algorithm, as held by the district court. Instead, Aristocrat contends that the structure disclosed in the specification of the ’102 patent, which was simply “any standard microprocessor base [sic] gaming machine [with] appropriate programming,” was a sufficient disclosure of structure under this court’s precedents.

In cases involving a computer-implemented invention in which the inventor has invoked means-plus-function claiming, this court has consistently required that the structure disclosed in the specification be more than simply a general purpose computer or microprocessor. The point of the requirement that the patentee disclose particular structure in the specification and that the scope of the patent claims be limited to that structure and its equivalents is to avoid pure functional claiming. As this court explained in Medical Instrumentation & Diagnostics Corp. v. Elekta AB, 344 F.3d 1205, 1211 (Fed. Cir. 2003), “If the specification is not clear as to the structure that the patentee intends to correspond to the claimed function, then the patentee has not paid the price but is attempting to claim in functional terms unbounded by any reference to structure in the specification.” See also Biomedino, LLC v. Waters Techs. Corp., 490 F.3d 946, 948 (Fed. Cir. 2007) (“[I]n return for generic claiming ability, the applicant must indicate in the specification what structure constitutes the means.”). For a patentee to claim a means for performing a particular function and then to disclose only a general purpose computer as the structure designed to perform that function amounts to pure functional claiming. Because general purpose computers can be programmed to perform very different tasks in very different ways, simply disclosing a computer as the structure designated to perform a particular function does not limit the scope of the claim to “the corresponding structure, material, or acts” that perform the function, as required by section 112 paragraph 6.

That was the point made by this court in WMS Gaming, Inc. v. International Game Technology, 184 F.3d 1339 (Fed. Cir. 1999). In that case, the court criticized the district court, which had determined that the structure disclosed in the specification to perform the claimed function was “an algorithm executed by a computer.” The district court erred, this court held, “by failing to limit the claim to the algorithm disclosed in the specification.” Id. at 1348. The rationale for that decision is equally applicable here: a general purpose computer programmed to carry out a particular algorithm creates a “new machine” because a general purpose computer “in effect becomes a special purpose computer once it is programmed to perform particular functions pursuant to instructions from program software.” Id., quoting In re Alappat, 33 F.3d 1526, 1545 (Fed. Cir. 1994). The instructions of the software program in effect “create a special purpose machine for carrying out the particular algorithm.” WMS Gaming, 184 F.3d at 1348. Thus, in a means-plus-function claim “in which the disclosed structure is a computer, or microprocessor, programmed to carry out an algorithm, the disclosed structure is not the general purpose computer, but rather the special purpose computer programmed to perform the disclosed algorithm.” Id. at 1349.
In a later case, this court made the same point, stating that a “computer-implemented means-plus-function term is limited to the corresponding structure disclosed in the specification and equivalents thereof, and the corresponding structure is the algorithm.” Harris Corp. v. Ericsson Inc., 417 F.3d 1241, 1253 (Fed. Cir. 2005). The court in that case characterized the rule of WMS Gaming as follows: “[T]he corresponding structure for a § 112 ¶ 6 claim for a computer-implemented function is the algorithm disclosed in the specification.” 417 F.3d at 1249.

In this case, Aristocrat acknowledges that the only portion of the specification that describes the structure corresponding to the three functions performed by the “control means” is the statement that it is within the capability of a worker in the art “to introduce the methodology on any standard microprocessor base [sic] gaming machine by means of appropriate programming.” ’102 patent, col. 3, ll. 2-4. That description goes no farther than saying that the claimed functions are performed by a general purpose computer. The reference to “appropriate programming” imposes no limitation whatever, as any general purpose computer must be programmed. The term “appropriate programming” simply references a computer that is programmed so that it performs the function in question, which is to say that the function is performed by a computer that is capable of performing the function.

Aristocrat offers two responses to the district court’s conclusion that the patent did not disclose sufficient structure. First, Aristocrat argues that the specification disclosed algorithms that were sufficient to constitute a qualifying disclosure of structure. Second, Aristocrat argues that no disclosure of specific algorithms was necessary in any event.. Next Page ->