Addressing the issue of when a "means-plus-function" claim element (in the context of a computer operated invention) suffers from 35 U.S.C. § 112, ¶ 2 indefiniteness due to the absence of clearly defined corresponding structure, a panel of the U.S. Court of Appeals for the Federal Circuit affirmed a lower court's decision on summary judgment finding all of the claims of the subject patent invalid for indefiniteness. Aristocrat Technologies Australia PTY Ltd. v. , Case No. 07-1419 (Fed. Cir., March 28, 2008) (Bryson, J.).
The decision arose out of Aristocrat's appeal of a decision, on summary judgment, that held Aristocrat's patent claim (that included a § 112, ¶ 6 claim element, i.e., "control means") invalid for indefiniteness under § 112, ¶ 2. The court stated that in the case of a means-plus-function claim "in which the disclosed structure is a computer or microprocessor programmed to carry out an algorithm, a corresponding structure must be a specific algorithm disclosed in the specification." Aristocrat appealed.
The patent claimed an improved gaming machine of the type prevalent in casinos. The patent disclosed that the claimed functions could be readily implemented by a non-inventive worker in the art on a microprocessor-based gaming machine by appropriate programming. As there was no evidence to contradict the finding that a skilled artisan could easily program an existing gaming machine to implement the claimed functions, Aristocrat argued that this disclosure complied with § 112, ¶ 2.
The panel disagreed, noting that to avoid purely functional claiming, "the structure disclosed in the specification [must] be more than simply a general purpose computer or microprocessor," since such disclosure would not limit the scope of the claim to the "corresponding structure, material or acts" as required by §112, ¶ 6. The panel further concluded that while "the sufficiency of the disclosure of algorithmic structure must be judged in the light of what one of ordinary skill in the art would understand the disclosure to impart," enablement was not the issue where disclosure of §112, ¶ 6 corresponding structure is concerned. Rather, according to Judge Bryson, the issue is whether sufficient structure is disclosed to limit the means plus function claim element to a particular structure and its equivalents. Relying on the Court's ruling in WMS Gaming, the panel thus adopted a bright-line test that requires, at the pain of invalidity for indefiniteness, disclosure of a specific algorithm in a patent where the claimed §112, ¶ 6 functions are performed by a microprocessor/computer.
Disclosure Note: McDermott represented Aristocrat in the reported case.
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