Print PDF

Patent Held Invalid for Failing to Disclose Algorithm Corresponding to Means-Plus-Function Claim Term

March 28, 2008
McAnulty, Timothy P.

Decision icon Decision

Last Month at the Federal Circuit - April 2008

Judges: Lourie, Schall, Bryson (author)

[Appealed from: D. Nev., Judge Sandoval]

In Aristocrat Technologies Australia Pty Ltd. v. International Game Technology, No. 07-1419 (Fed. Cir. Mar. 28, 2008), the Federal Circuit affirmed the district court’s holding that all claims of Aristocrat Technologies Australia Pty Limited and Aristocrat Technologies, Inc.’s (collectively “Aristocrat”) patent were invalid for indefiniteness. In particular, the Federal Circuit held that the patent was invalid for failing to recite an algorithm corresponding to the means-plus-function terms recited in the asserted claim.

Aristocrat asserted U.S. Patent No. 6,093,102 (“the ’102 patent”) against International Game Technology and IGT (collectively “IGT”). The ’102 patent is directed to an electronic slot machine that allows a player to select winning combinations of symbol positions. The district court noted, and the parties agreed, that the term “game control means” or “control means,” used in several instances in claim 1, was a means-plus-function term that invoked 35 U.S.C. § 112, ¶ 6. The district court held the claims of the ’102 patent invalid because the specification lacked any specific algorithm or any step-by-step process for performing the claimed functions of the claimed “control means.”

On appeal, Aristocrat first argued that the district court erred by failing to construe the functions of the term “control means” under section 112, ¶ 6 and, thus, could not have properly determined whether the specification recited adequate corresponding structure. The Federal Circuit disagreed, noting that the district court effectively gave a construction of the functions of the “control means limitation” when it described the claimed functions and stated that the specification contained no algorithm that described or recited those functions.

Aristocrat also contended that the language of claim 1 of the ’102 patent, when referring to the game control means, implicitly disclosed an algorithm for the microprocessor. The Court rejected this contention because the language simply described the function to be performed and not the algorithm by which it is performed. The Court also found that other language pointed to by Aristocrat merely described the outcome of performing a function and was not an algorithm that described how the function is performed. The Court further rejected Aristocrat’s contention that the description of embodiments within the ’102 patent delineated the appropriate programming because it was instead simply a description of the outcome of the claimed functions and not a description of the structure.

The Federal Circuit also rejected Aristocrat’s contention that it is not necessary to disclose a particular algorithm in order to disclose sufficient structure for a means-plus-function limitation in a computer-implemented invention. The Court distinguished In re Dossel, 115 F.3d 942 (Fed. Cir. 1997), where the patent at issue provided “an extremely detailed disclosure of all information necessary to perform the function, except for basic mathematical techniques that would be known to any person skilled in the pertinent art.” Slip op. at 13.

The Federal Circuit also rejected Aristocrat’s contention that that disclosure of a microprocessor with “appropriate programming” was sufficient to enable one of ordinary skill in the art to build the claimed device. The Court found this argument conflated the enablement requirement under section 112, ¶ 1 and the requirement to disclose the structure that performs the recited function under section 112, ¶ 6. The Court explained that “[a]lthough the examples given in the ’102 patent might enable one of ordinary skill to make and use the invention, they do not recite the particular structure that performs the function and to whichthe means-plus-function claim is necessarily limited.” Id. at 14.