Patent Law

An Algorithm Shy

By Gary Odom and Jordan Kuhn

Australia-based Aristocrat threw away money getting gaming machine patent 6,093,102, and then threw away money trying to enforce it. Means-plus-function with no unction. From the CAFC, a crash course in means-plus-function claims for computers: the claimed function is bounded by the specifically disclosed algorithm. Lacking an algorithmic tether, a means-plus-function processor claim is indefinite.

Aristocrat v. International Game Technology (CAFC 2007-1419)

The game disclosed in the '102 patent purportedly increases player interest in slot machines by providing the player with greater control over the definition of winning opportunities. It allows the player to define the winning opportunities based on symbols displayed on the top and side of a multi-line screen representing slot machine reels. Using the invention on a 3x5 screen, for example, the player can define numerous different arrangements that will allow the player to win for some subset of the 243 possible winning combinations. The player can do so by selecting symbol positions and thereby activating winning opportunities for combinations in which the symbols are not necessarily aligned with one another. The only constraint is that the selected combination must contain at least one symbol from each column. Figure 2 from the '102 patent shows a 3x5 screen with selections, and the figure on the right shows one of the winning combinations for the selection in Figure 2.

'102 had only one independent claim, the crucial element a "game control means," aka "control means."

A gaming machine
    having display means arranged to display a plurality of symbols in a display format having an array of n rows and m columns of symbol positions,
    game control means arranged to control images displayed on the display means,
    the game control means being arranged to pay a prize when a predetermined combination of symbols is displayed in a predetermined arrangement of symbol positions selected by a player, playing a game, including one and only one symbol position in each column of the array,
    the gaming machine being characterised in that selection means are provided to enable the player to control a definition of one or more predetermined arrangements by selecting one or more of the symbol positions and
    the control means defining a set of predetermined arrangements for a current game comprising each possible combination of the symbol positions selected by the player which have one and only one symbol position in each column of the display means,
    wherein the number of said predetermined arrangements for any one game is a value which is the product k1 . . . x . . . ki . . . x . . . km where ki is a number of symbol positions which have been selected by the player in an ith column of the n rows by m columns of symbol positions on the display (0 < i ≤ m and ki ≤ n).

The district court noted that the parties agreed the term "control means" is a means-plus-function term that invokes 35 U.S.C. § 112 ¶ 6. As such, the scope of that claim limitation had to be defined by the structure disclosed in the specification plus any equivalents of that structure; in the absence of structure disclosed in the specification to perform those functions, the claim limitation would lack specificity, rendering the claim as a whole invalid for indefiniteness under 35 U.S.C. § 112 ¶ 2. See In re Donaldson, 16 F.3d 1189, 1195 (Fed. Cir. 1994) (en banc).

The court noted that there were slight linguistic differences in the parties' characterizations of the functions performed by the "control means," but that the differences were unimportant, because there was no adequate disclosure of structure in the specification to perform those functions, regardless of how they were defined.

The district court poohed Aristrocrat's hand waving that there was "appropriate programming."

The court ruled that "[m]erely stating that a standard microprocessor is the structure without more is not sufficient." In particular, the court noted that the specification did not create any specific structure or new machine because "it does not set forth any specific algorithm" for performing the recited function.

On appeal, Aristocrat argued that a general purpose microprocessor was sufficient for satisfying § 112 ¶ 6. Laughter peeled from the appeals court panel. Such a claim would be so broad.

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.

Aristocrat was not required to produce a listing of source code or a highly detailed description of the algorithm to be used to achieve the claimed functions in order to satisfy 35 U.S.C. § 112 ¶ 6. It was required, however, to at least disclose the algorithm that transforms the general purpose microprocessor to a "special purpose computer programmed to perform the disclosed algorithm." WMS Gaming, 184 F.3d at 1349.

Aristocrat's sorry arguments confused outcome with algorithm, confused enablement with § 112 ¶ 6 requisite. Aristocrat's cited case law was off-point.

Affirmed.

Lead counsel for Aristocrat was Brian E. Ferguson of McDermott, Will & Emery.

Full post as published by The Patent Prospector on March 30, 2008 (boomark / email).