By: Alexander Cullen — Legal Intern, Unified Patents

For those seeking to file applications for computer-implemented inventions, it pays to be aware of some lesser known requirements for such inventions before casting the die. In July of 2000, the United States Patent Office (USPTO) issued a patent for an electronic slot machine designed to appeal to players by allowing the conditions for payout to be selected by the players. Patent 6,093,102 (`102 Patent), assigned to Aristocrat Technologies Inc., comprised of the conventional slot machine set up plus a display screen whereby players can select their own winning combinations. The intended result is a perception of increased winning opportunities incentivizing slot players into preferring to play the machine. However, after filing suit for patent infringement against International Game Technology of `102 Patent in 2006, Aristocrat would find themselves in the position of those who use their alleged invention; the odds not being in their favor.

On summary judgment the United States District Court for the District of Nevada found the `102 patent invalid for indefiniteness under 35 U.S.C. §112(b). Aristocrat Techs. Austl. Pty v. Int'l Game Tech., No. 2:05-CV-00820-BES (LRL), 2007 U.S. Dist. LEXIS 98916 (D. Nev. Apr. 20, 2007). The house would later go bust as the United States Federal Court of Appeals for the Federal Circuit affirmed the `102 Patent’s invalidity. Aristocrat Techs. Austl. Pty. Ltd. v. Int’l Game Tech., 521 F.3d 1328, 1338 (Fed. Cir. 2008). Had the specification’s disclosure contained an algorithm, it may have been sufficient, and appeal would have been a gamble Aristocrat never had to make.   

In computer-implemented inventions, mean-plus-function claim limitations under 35 U.S.C. §112(f), are effective for claiming a function without limiting it to a particular piece of hardware. Functional claims recite performing a function without reciting structure, materials or acts that perform the function. Claiming a function itself expands the scope of the claim for the invention and prevents potential infringers from navigating around claim limitations by using alternate components. But 112(f) also requires that for means-plus-function limitations, the patent specification disclose corresponding structures to perform all the claimed functions or the claim be found indefinite. To the rue of Aristocrat, for computer-implemented functions the structure disclosed in the specification must be an algorithm.

On appeal, Aristocrat argued that disclosure of a programmable microprocessor ought to have been sufficient to satisfy definiteness related to a “game controls means” claim. Aristocrat Techs. Austl. Pty. Ltd. v. Int’l Game Tech., 521 F.3d at 1336. The control means in the slot machine functioned to present symbols on the display, operate win conditions, and service payouts. Presented in support were the mathematical equations for performing the functions, arrangements describing the operation of the game, and written descriptions. Id. at 1334. In combination, Aristocrat argued that to one of reasonable skill in the art these implicitly disclosed sufficient corresponding structure to satisfy definiteness. Id. at 1336. Aristocrat further claimed a particular algorithm is not necessary to disclose sufficient structure for a mean-plus-function limitation. Id. at 1335.

The Federal Circuit rejected Aristocrat’s arguments. Id. at 1338. It upheld the district court’s finding of indefiniteness because rather than disclose the structure of an algorithm capable of performing the functions, the specification only repeated aspects of the game like betting odds. Id. at 1332. The court agreed with Aristocrat that the disclosures could enable one skilled in the art to devise an algorithm sufficient to support the function claim but, the question of definiteness in this case was whether an algorithm had been disclosed at all. Id. at 1337. The court then subsequently rejected the assertion an algorithm was unnecessary for disclosing structure in computer-implemented inventions. Id. at 1338.

This case provides insight and warning about satisfying definiteness in computer-implemented means-plus-function claims. As per Aristocrat’s own example, for inventors seeking to patent computer-implemented-inventions, understanding why 112(b) specifically requires an algorithm for corresponding structure can be vital. The answer: preventing “pure functional claiming” and promoting patent quality.

As to why, the USPTO’s 2019 examination guidance action on patent examinations of computer-implemented inventions with functional claims elaborates. First, pure functional claims raise an issue of indefiniteness because they claim an abstraction without description of how the result is achieved. Second, without disclosure of the structure performing the claimed function, the scope of the claim is implicitly ANY structure capable of performing the function and the function itself. The result of both is indefiniteness because there is a function without adequate limitation to structure. Thus, requiring an algorithm prohibits overly broad and indefinite claim scoping. 

It should be noted, definiteness for computer-implemented functional claims does not necessarily require disclosing a highly descriptive algorithm, only one sufficient in structure to enable the function. Aristocrat Techs. Austl. Pty. Ltd. v. Int’l Game Tech., 521 F.3d at 1338. Specifications may disclose the algorithm in terms of mathematics, language, flow charts, or any means conveying understanding to those of ordinary skill in the art. Id. at 1337. Aristocrat’s slot machine only disclosed a microprocessor as structure for its game control function, by consequence any algorithm that achieved the results of the game control by microprocessor would be infringing. Said otherwise, it was a purely functional claim citing a goal rather than one reciting with specificity how said goal is achieved.

Necessarily, compliance with section 112(b) definiteness requirement should be of concern for those seeking to patent computer-implemented inventions with functional claims. Disclosure of algorithms providing sufficient structure to accomplish the claimed function is essential to avoid a finding of indefiniteness.