United States Court of Appeals for the Federal Circuit
2007-1419
ARISTOCRAT TECHNOLOGIES AUSTRALIA PTY LIMITED
and ARISTOCRAT TECHNOLOGIES, INC.,
Plaintiffs-Appellants,
v.
INTERNATIONAL GAME TECHNOLOGY
and IGT,
Defendants-Appellees.
Brian E. Ferguson, McDermott, Will & Emery LLP, of Washington, DC, argued for
plaintiffs-appellants. With him on the brief was Amalie M. Weber. Of counsel on the
brief were Terrence P. McMahon, Anthony R. De Alcuaz, and Robert J. Blanch, of Palo
Alto, California.
Jeffrey W. Sarles, Mayer Brown LLP, of Chicago, Illinois, argued for defendants-
appellees. With him on the brief were Melissa A. Anyetei and Andrea C. Hutchison.
Appealed from: United States District Court for the District of Nevada
Judge Brian E. Sandoval
United States Court of Appeals for the Federal Circuit
2007-1419
ARISTOCRAT TECHNOLOGIES AUSTRALIA PTY LIMITED
and ARISTOCRAT TECHNOLOGIES, INC.,
Plaintiffs-Appellants,
v.
INTERNATIONAL GAME TECHNOLOGY
and IGT,
Defendants-Appellees.
Appeal from the United States District Court for the District of Nevada in
case no. 05-CV-820, Judge Brian E. Sandoval.
___________________________
DECIDED: March 28, 2008
___________________________
Before LOURIE, SCHALL, and BRYSON, Circuit Judges.
BRYSON, Circuit Judge.
The appellants, referred to collectively as “Aristocrat,” are the owner and
exclusive licensee of U.S. Patent No. 6,093,102 (“the ’102 patent”). The patent is
directed to an electronic slot machine that allows a player to select winning
combinations of symbol positions. The appellees, referred to collectively as “IGT,”
manufacture and sell gaming products that Aristocrat asserts infringe the ’102 patent.
In an infringement action brought by Aristocrat against IGT in the United States District
Court for the District of Nevada, the district court held all of the claims of the ’102 patent
invalid for indefiniteness.
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.
A winning combination
On summary judgment, the trial court held all of the claims of the ’102 patent
invalid. Aristocrat does not dispute that all of the claims rise and fall together. Like the
parties, we therefore focus on independent claim 1.
2007-1419 2
Claim 1 reads as follows:
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).
I
The district court observed that the key question in this case is the definiteness of
the claim term “game control means” or “control means” that is used several times in
claim 1. The court explained that the claim describes the “game control means” as
performing three functions: (1) to control images displayed on the display means; (2) to
pay a prize when a predetermined combination of symbols matches the symbol
2007-1419 3
positions selected by the player; and (3) to define the pay lines for the game according
to each possible combination of the selected symbol positions.
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.
Although Aristocrat argued that the structure corresponding to the recited functions was
a standard microprocessor-based gaming machine with “appropriate programming,” the
court noted that the specification contained no “guidance to determine the meaning of
‘standard microprocessor’ or ‘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.
Citing decisions of this court, the trial court explained that in a means-plus-
function claim “in which the disclosed structure is a computer or a microprocessor
2007-1419 4
programmed to carry out an algorithm, a corresponding structure must be a specific
algorithm disclosed in the specification, rather than merely ‘an algorithm executed by a
computer.’” Because the specification of the ’102 patent lacks “any specific algorithm”
or any “step-by-step process for performing the claimed functions of controlling images
on the slot machines [sic] video screen, paying a prize when a predetermined
combination of symbols comes up or defining the pay lines for games,” the court held
the asserted structure to be insufficient to satisfy section 112 paragraph 6. In addition,
the district court held that the specification did not link the asserted structure to any of
the claimed functions. The court held claim 1 invalid for that reason as well.
II
On appeal, Aristocrat first argues that the district court erred by failing to construe
the disputed term “game control means” or “control means” in claim 1. Aristocrat
argues that because the district court did not construe the functions of the “control
means” term under 35 U.S.C. §112 ¶ 6, it could not have properly determined whether
the specification recited adequate structure corresponding to those functions.
The district court stated that “[t]he determination as to which function description
is the accurate construction is not pertinent to the summary judgment motion because
the structure is lacking in description and is not found in the specification.” Aristocrat
argues that our decision in Oakley, Inc. v. Sunglass Hut Int’l, 316 F.3d 1331, 1340 (Fed.
Cir. 2003), requires that a “determination [of definiteness] requires a construction of the
claims according to the familiar canons of claim construction.”
The district court committed no error in its analysis of the means-plus-function
limitation in this case. The court described the two competing claim constructions
2007-1419 5
proposed by the parties, and the court’s description made clear that there was virtually
no difference between them. Moreover, the district court, later in its opinion, effectively
gave a construction of the functions of the “control means” limitation when it stated that
the specification contained no algorithm that described or recited the claimed functions.
Describing the claimed functions, the court wrote: “The specification contains no step-
by-step process for performing the claimed functions of controlling images on the slot
machine’s video screen, paying a prize when a predetermined combination of symbols
comes up or defining the pay lines for games.” That characterization of the claimed
functions of the “game control means” is not materially different from the
characterization that Aristocrat argues the district court should have adopted in
analyzing the means-plus-function limitation. To the extent the court’s characterization
differs from Aristocrat’s, it is only because the court’s characterization omits some of the
detail found in Aristocrat’s characterization. The omission of that detail, however, has
no effect on the question whether the specification discloses sufficient structure to
perform the claimed functions. In fact, Aristocrat’s description of the claimed function
would appear to require more by way of specificity in the disclosed structure than would
the court’s characterization. The district court therefore committed no reversible error
with respect to this issue.
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
2007-1419 6
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
2007-1419 7
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
2007-1419 8
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.
A
As to the first argument, Aristocrat contends that the language of claim 1
referring to “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” implicitly discloses an algorithm for the
2007-1419 9
microprocessor. That is, when the winning combination of symbols is displayed, the
program should pay a prize. But that language simply describes the function to be
performed, not the algorithm by which it is performed. Aristocrat’s real point is that
devising an algorithm to perform that function would be within the capability of one of
skill in the art, and therefore it was not necessary for the patent to designate any
particular algorithm to perform the claimed function. As we have noted above, however,
that argument is contrary to this court’s law.
Aristocrat also points to language in claim 1 that, according to Aristocrat, “sets
forth the mathematical equation that describes the result of practicing the third function.”
The language in question recites “defining a set of predetermined arrangements for a
current game comprising each possible combination of the symbol position selected by
the player which have one and only one symbol position in each column of the display
means.” The problem with Aristocrat’s argument is underscored by Aristocrat’s very
characterization of the role of the equation: It describes the result of practicing the third
function. That is, the equation is not an algorithm that describes how the function is
performed, but is merely a mathematical expression that describes the outcome of
performing the function. To be sure, as Aristocrat argues, the equation “restricts
‘appropriate programming’ to algorithms which result in the specified number of winning
opportunities.” But that argument simply concedes that the equation describes an
outcome, not a means for achieving that outcome. The equation thus does not disclose
the structure of the claimed device, but is only another way of describing the claimed
function.
2007-1419 10
Finally, Aristocrat contends that “the written description delineates what
constitutes ‘appropriate programming’ through the disclosed embodiments of the
invention.” Again, however, the description of the embodiments is simply a description
of the outcome of the claimed functions, not a description of the structure, i.e., the
computer programmed to execute a particular algorithm.
In making this argument, Aristocrat relies on Figure 1 and Table 1 from the
patent, which provide examples of how player selections translate to possible winning
combinations:
Two other pairs of figures and tables, Figures 3 and 4, and Tables 2 and 3, offer
similar examples. The corresponding portion of the written description contains
mathematical descriptions of how many winning combinations would be produced. ’102
patent, col. 3, line 54, through col. 5, line 21. Aristocrat refers to these examples as
“algorithms.” The figures, tables, and related discussion, however, are not algorithms.
They are simply examples of the results of the operation of an unspecified algorithm.
Like the mathematical equation set forth in claim 1, these combinations of figures and
2007-1419 11
tables are, at best, a description of the claimed function of the means-plus-function
claim.
Aristocrat has elected to claim using section 112 paragraph 6 and therefore must
disclose corresponding structure. It has disclosed, at most, pictoral and mathematical
ways of describing the claimed function of the game control means. That is not enough
to transform the disclosure of a general-purpose microprocessor into the disclosure of
sufficient structure to satisfy section 112 paragraph 6.
B
In support of the 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, Aristocrat relies primarily on In re Dossel, 115 F.3d
942 (Fed. Cir. 1997). Aristocrat argues that the application in Dossel did not disclose a
particular algorithm, and that the court held the disclosure sufficient even though the
application stated, with respect to the performance of one of the claimed functions, that
“[k]nown algorithms can be used for this purpose.”
The means-plus-function limitation at issue in Dossel was a “means for
reconstructing the current distribution” on the surface of an element inside a biological
object, such as on the surface of a tumor inside a human brain. The application stated
that the reconstruction unit would reconstruct the density of the current at various points
on that surface from the values of the magnetic flux density at corresponding pixels at
the same time. See U.S. Patent No. 5,885,215, col. 4, ll. 6-10 (the patent that issued
from the Dossel application). The application explained that “[k]nown algorithms can be
used for this purpose.” Id., col. 4, ll. 10-11. The application then provided the particular
2007-1419 12
equation by which the relationship between the values of magnetic flux density and
current density could be described in matrix form, id., col. 4, ll. 12-15, and it described in
great detail the components of that equation, id., col. 4, ll. 16-55. Accordingly, while
providing a detailed explanation of how the claimed device would perform the claimed
function, the specification left the mathematical techniques used to solve the recited
equations to persons of ordinary skill in the art. That is what this court referred to when
it stated that the application stated “that ‘known algorithms’ can be used to solve
standard equations which are known in the art.” Dossel, 115 F.3d at 946.
From the context and from reviewing the application, it is clear that the Dossel
court used the term “algorithm” in a narrow sense, referring to particular well-known
mathematical operations that could be used to solve the equations disclosed in the
application. Far from supporting Aristocrat’s claim that a reference to a general purpose
computer with “appropriate programming” discloses sufficient structure for section 112
paragraph 6, the Dossel case provides an example of 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.
Aristocrat also argues that, even if there is no disclosure of an algorithm in the
patent, the disclosure of a microprocessor with “appropriate programming” is a sufficient
disclosure of structure for means-plus-function purposes, because the evidence showed
that one of ordinary skill in the art could build the device claimed in the ’102 patent
based on the disclosure in the specification. That argument, however, conflates the
requirement of enablement under section 112 paragraph 1 and the requirement to
disclose the structure that performs the claimed function under section 112 paragraph 6.
2007-1419 13
Although 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 which the means-plus-function claim is necessarily limited.
Whether the disclosure would enable one of ordinary skill in the art to make and
use the invention is not at issue here. Instead, the pertinent question in this case is
whether Aristocrat’s patent discloses structure that is used to perform the claimed
function. Enablement of a device requires only the disclosure of sufficient information
so that a person of ordinary skill in the art could make and use the device. A section
112 paragraph 6 disclosure, however, serves the very different purpose of limiting the
scope of the claim to the particular structure disclosed, together with equivalents. The
difference between the two is made clear by an exchange at oral argument. In
response to a question from the court, Aristocrat’s counsel contended that, in light of the
breadth of the disclosure in the specification, any microprocessor, regardless of how it
was programmed, would infringe claim 1 if it performed the claimed functions recited in
the means-plus-function limitations of that claim. That response reveals that Aristocrat
is in essence arguing for pure functional claiming as long as the function is performed
by a general purpose computer. This court’s cases flatly reject that position.
For example, in Atmel Corp. v. Information Storage Devices, Inc., 198 F.3d 1374,
1380 (Fed. Cir. 1999), the court embraced the proposition that “consideration of the
understanding of one skilled in the art in no way relieves the patentee of adequately
disclosing sufficient structure in the specification.” It is not enough for the patentee
simply to state or later argue that persons of ordinary skill in the art would know what
structures to use to accomplish the claimed function. The court in Biomedino, LLC v.
2007-1419 14
Waters Technologies Corp., 490 F.3d 946, 953 (Fed. Cir. 2007), put the point this way:
“The inquiry is whether one of skill in the art would understand the specification itself to
disclose a structure, not simply whether that person would be capable of implementing
that structure.” Discussing Atmel, the court in Biomedino stated:
In Atmel, it was not the fact that one skilled in the art was aware of
known circuit techniques that resulted in a conclusion that sufficient
structure was recited. Rather, it was the inclusion in the written
description of the title of [a technical article] which itself described the
structure for a “known circuit technique.” Expert testimony was used to
show what the title of the article would convey to one skilled in the art—in
this case it was the “precise structure of the means recited in the
specification.” . . . The expert’s testimony did not create or infer the
structure.
490 F.3d at 952.
Aristocrat relies on a statement from the recent decision of this court in AllVoice
Computing PLC v. Nuance Communs., Inc., 504 F.3d 1236, 1245 (Fed. Cir. 2007),
where the court stated that in software cases “algorithms in the specification need only
disclose adequate defining structure to render the bounds of the claim understandable
to one of ordinary skill in the art.” We similarly stated in Medical Instrumentation &
Diagnostics Corp. v. Elekta AB, 344 F.3d 1205, 1214 (Fed. Cir. 2003), that “there would
be no need for a disclosure of the specific program code if software were linked to
the . . . function and one skilled in the art would know the kind of program to use.”
It is certainly true that the sufficiency of the disclosure of algorithmic structure
must be judged in light of what one of ordinary skill in the art would understand the
disclosure to impart. See, e.g., Intel Corp. v. VIA Techs., 319 F.3d 1357, 1367 (Fed.
Cir. 2003) (knowledge of a person of ordinary skill in the art can be used to make clear
how to implement a disclosed algorithm); Atmel Corp., 198 F.3d at 1379 (“[T]he ‘one
2007-1419 15
skilled in the art’ analysis should apply in determining whether sufficient structure has
been disclosed to support a means-plus-function limitation.”). That principle, however,
has no application here, because in this case there was no algorithm at all disclosed in
the specification. The question thus is not whether the algorithm that was disclosed
was described with sufficient specificity, but whether an algorithm was disclosed at all.
In Medical Instrumentation, we held that the proper inquiry for purposes of
section 112 paragraph 6 analysis is to “look at the disclosure of the patent and
determine if one of skill in the art would have understood that disclosure to encompass
software [to perform the function] and been able to implement such a program, not
simply whether one of skill in the art would have been able to write such a software
program.” 344 F.3d at 1212 (emphasis in original). We then stated that it is “not proper
to look to the knowledge of one skilled in the art apart from and unconnected to the
disclosure of the patent.” Id. That is precisely the inquiry the district court performed
and that we reviewed above. Here, as in Medical Instrumentation, the patent does not
disclose the required algorithm or algorithms, and a person of ordinary skill in the art
would not recognize the patent as disclosing any algorithm at all. Accordingly, the
means-plus-function limitations of claim 1 lacked sufficient disclosure of structure under
35 U.S.C. § 112 ¶ 6 and were therefore indefinite under 35 U.S.C. § 112 ¶ 2.
IV
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
2007-1419 16
computer programmed to perform the disclosed algorithm.” WMS Gaming, 184 F.3d at
1349. Because the district court correctly held that was not done in this case, we
uphold the judgment of the district court.
AFFIRMED.
2007-1419 17