## 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 defendantsappellees. With him on the brief were Melissa A. Anyetei and Andrea C. Hutchison

. Appealed from: United States Distric t 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, J udge Brian E. Sandoval.

__________________ _________ DECIDED: March 28, 2008

__________________ _________ Before LOURIE, SCHALL, and BRYSON, Circuit Judges

. BRYSON, Circuit Judge

. The appellants, referred to collective ly as “Aristocrat,” are the owner and exclusive licensee of U.S. Patent No. 6,09 3,102 (“the ’102 patent”). The patent is directed to an electronic slot machine t hat allows a player to select winning combinations of symbol positions. The appel lees, referred to colle ctively as “IGT,” manufacture and sell gaming pr oducts that Aristocrat assert s 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 cl aims of the ’102 patent invalid for indefiniteness.The game disclosed in the ’102 patent purpor tedly increases player interest in slot machines by providing t he player with greater control over the definition of winning opportunities. It allows the player to def ine the winning opportuni ties based on symbols displayed on the top and side of a multi-line screen represent ing 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 c an do so by selecting symbol positions and thereby activating winning opportunities for co mbinations 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 focu s on independent claim 1.

2007-1419 22007-1419 3 Claim 1 reads as follows: A gaming machine having display means arranged to disp lay 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 contro l images displayed on the display means, the game control means being a rranged to pay a prize when a predetermined combination of symbols is displayed in a predetermined arrangement of sym bol 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 characteris ed 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 possi ble 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 predet ermined arrangements for any one game is a value which is the product k 1 . . . x . . . k i . . . x . . . k m where k i is a number of symbol positions which have been selected by the player in an i th column of the n rows by m columns of symbol positions on the display (0 < i ≤ m and k i ≤ n).
I The district court observed that the key ques tion in this case is the definiteness of the claim term “game control means” or “contro l means” that is used several times in claim 1. The court explained that the cl aim describes the “game control means” as performing three functions: (1) to control im ages displayed on the display means; (2) to pay a prize when a predetermined combi nation of symbols matches the symbol2007-1419 4 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 discl osed in the specification to perform those functions, the claim limitation would lack specificity, rendering the claim as a whole invalid for indefinit eness 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 perform ed by the “control m eans,” but that the differences were unimportant, because there was no adequate disclosur e 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 machin e with “appropriate programming,” the court noted that the s pecification contained no “guidance to determine the meaning of ‘standard microprocessor’ or ‘a ppropriate programming.’” Th e court ruled that “[m]erely stating that a standard microprocessor is the st ructure without more is not sufficient.” In particular, the court noted that the specification did not creat e 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 tria l court explained t hat in a means-plusfunction claim “in which the disclosed structure is a co mputer or a microprocessor2007-1419 5 programmed to carry out an algorithm, a co rresponding structure mu st be a specific algorithm disclosed in the spec ification, rather than merely ‘an algorithm executed by a computer.’” Because the spec ification of the ’102 patent la cks “any specific algorithm” or any “step-by-step process for performing t he claimed functions of controlling images on the slot machines [sic] video screen, paying a prize when a predetermined combination of symbols comes up or defini ng the pay lines for games,” the court held the asserted structure to be insufficient to sa tisfy section 112 paragrap h 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 di strict court erred by failing to construe the disputed term “game contro l 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 struct ure corresponding to those functions. The district court stated that “[t]he dete rmination as to which function description is the accurate construction is not perti nent to the summary judgment motion because the structure is lacking in de scription and is not found in t he 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 “det ermination [of definiteness] r equires 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 descr ibed the two competing claim constructions2007-1419 6 proposed by the parties, and the court’s descrip tion made clear that there was virtually no difference between them. Moreover, the distri ct court, later in its opinion, effectively gave a construction of the functions of the “c ontrol 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 spec ification contains no stepby-step process for performing the claimed func tions of controlling images on the slot machine’s video screen, payin g a prize when a predetermi ned 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 di fferent 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 th e 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, Aristo crat’s description of the claimed function would appear to require more by way of spec ificity 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 t he district court was wrong to hold that the patent’s disclosure of a general purpose, programmabl e microprocessor was not a sufficient disclosure of structure to sati sfy section 112 paragraph 6. In particular, Aristocrat argues that computer-implemented means-plus-func tion claims do not require2007-1419 7 disclosure of a corresponding algorit hm, 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-implement ed invention in whic h the inventor has invoked means-plus-function claiming, this court has consistently required that the structure disclosed in the spec ification be more than simply a general purpose computer or microprocessor. The poin t of the requirement that the patentee disclose particular structure in the specificati on 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 stru cture 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 claimi ng ability, the applicant must indicate in the specification what structure constitute s 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 perfo rm that function amounts to pure functional claiming. Because general purpose comput ers can be programmed to perform very different tasks in very different ways, simp ly disclosing a computer as the structure designated to perform a particular function does not limit the scope of the claim to “the2007-1419 8 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 t hat case, the court criticized the district court, which had dete rmined that the structure disclos ed 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 li mit the claim to the algorithm disclosed in the specification.” Id. at 1348. The rationale for that dec ision is equally applicable here: a general purpose computer progr ammed 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 instructio ns 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 clai m “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 “computerimplemented means-plus-function term is limited to the corresponding structure disclosed in the specification and equivale nts 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 c haracterized the rule of WMS Gaming as follows: “[T]he2007-1419 9 corresponding structure for a § 112 ¶ 6 clai m for a computer-implemented function is the algorithm disclosed in the s pecification.” 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 t hat it is within the capability of a worker in the art “to introduce the methodology on any standard mi croprocessor base [sic] gaming machine by means of appropriate programming.” ’102 pat ent, 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 “appropr iate programming” imposes no limitation whatever, as any general purpose com puter 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 di strict court’s conclusi on that the patent did not disclose sufficient structure. Firs t, Aristocrat argues that the specification disclosed algorithms that were sufficient to constitute a qualifying disclosure of structure. Second, Aristocr at 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 sy mbols is displayed in a pr edetermined arrangement of symbol positions selected by a player” implicitly discloses an algorithm for the2007-1419 10 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. Aristo crat’s real point is that devising an algorithm to perform that func tion would be within th e 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 cl aim 1 that, according to Aristocrat, “sets forth the mathematical equation t hat describes the result of pr acticing the third function.” The language in question recites “defining a set of predetermined arrangements for a current game comprising each possible combinat ion of the symbol posi tion selected by the player which have one and on ly one symbol position in each column of the display means.” The problem with Ar istocrat’s argument is undersco red by Aristocrat’s very characterization of the role of the equation: It describes the result of practicing the third function. That is, the equatio n is not an algorithm that describes how the function is performed, but is merely a mathematical ex pression that describes the outcome of performing the function. To be sure, as Aristocrat argues, the equation “restricts ‘appropriate programming’ to algorithms which re sult in the specifie d number of winning opportunities.” But that ar gument simply concedes that the equation describes an outcome, not a means for achieving that out come. The equation thus does not disclose the structure of the claimed device, but is only another wa y of describing the claimed function.Finally, Aristocrat contends that “t he written description delineates what constitutes ‘appropriate programming’ th rough the disclosed embodiments of the invention.” Again, however, the description of the embodi ments is simply a description of the outcome of the claim ed functions, not a description of the structure, i.e., the computer programmed to exec ute a particular algorithm. In making this argument, Aristocrat re lies on Figure 1 and Table 1 from the patent, which provide examples of how player selections tr anslate to possible winning combinations:

Two other pairs of figures and tables, Fi gures 3 and 4, and Tables 2 and 3, offer similar examples. The corresponding porti on of the written description contains mathematical descriptions of how many winni ng combinations would be produced. ’102 patent, col. 3, line 54, through co l. 5, line 21. Aristocrat re fers to these examples as “algorithms.” The figures, tables, and rela ted discussion, however, are not algorithms. They are simply examples of the results of the operation of an un specified algorithm. Like the mathematical equation set forth in claim 1, these combinations of figures and

2007-1419 112007-1419 12 tables are, at best, a description of the claimed function of the means-plus-function claim. Aristocrat has elected to claim usi ng section 112 paragraph 6 and therefore must disclose corresponding structure. It has disclo sed, at most, pictor al and mathematical ways of describing the claimed function of the game control me ans. That is not enough to transform the disclosure of a general-pur pose microprocessor into the disclosure of sufficient structure to sa tisfy 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 stru cture for a means-plus-f unction limitation in a computer-implemented invention, Aristocrat relies primarily on In re Dossel , 115 F.3d 942 (Fed. Cir. 1997). Aristocrat ar gues that the application in Dossel did not disclose a particular algorithm, and that the court hel d 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 lim itation at issue in Dossel was a “means for reconstructing the current dist ribution” on the surface of an element inside a biological object, such as on the surface of a tumor in side a human brain. T he application stated that the reconstruction unit w ould reconstruct the density of the current at various points on that surface from the values of the magnetic flux densit y 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 particular2007-1419 13 equation by which the relationship between the values of magnet ic flux density and current density could be described in matrix form, id. , col. 4, ll. 12-15, and it described in great detail the component s of that equation, id. , col. 4, ll. 16-55. Accordingly, while providing a detailed explanati on 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 w hat this court referred to when it stated that the applicati on stated “that ‘known algorith ms’ 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 th e 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 supporti ng Aristocrat’s claim that a reference to a general purpose computer with “appropriate pr ogramming” 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 t here is no disclosure of an algorithm in the patent, the disclosure of a micr oprocessor with “appropriate programming” is a sufficient disclosure of structure for means-plus-function purposes, because the evidence showed that one of ordinary skill in t he art could build the device claimed in the ’102 patent based on the disclosure in the specification. That argu ment, however, conflates the requirement of enablement under secti on 112 paragraph 1 and the requirement to disclose the structure that per forms the claimed function under section 112 paragraph 6.2007-1419 14 Although the examples giv en in the ’102 patent might enable one of ordinary skill to make and use the invention, th ey 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. In stead, the pertinent questi on in this case is whether Aristocrat’s patent discloses stru cture that is used to perform the claimed function. Enablement of a device requires only the disclosur e of sufficient information so that a person of ordinary sk ill in the art could make and use the device. A section 112 paragraph 6 disclosure, however, serves t he very different purpose of limiting the scope of the claim to the particular structur e disclosed, together wit h equivalents. The difference between the two is made clear by an exchange at oral argument. In response to a question from the court, Aristocr at’s counsel contended that, in light of the breadth of the disclosure in t he specification, any microproc essor, regardless of how it was programmed, would infringe claim 1 if it performed the claimed functions recited in the means-plus-function limitatio ns of that claim. That re sponse 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 “con sideration of the understanding of one skilled in the art in no way relieve s the patentee of adequately disclosing sufficient structure in the specif ication.” 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 t he claimed function. The court in Biomedino, LLC v.2007-1419 15 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 spec ification itself to disclose a structure, not simp ly 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 resu lted in a conclusion that sufficient structure was recited. Rather, it was the inclusion in the written description of the title of [a techni cal article] which itself described the structure for a “known circuit techni que.” Expert testimony was used to show what the title of the article w ould convey to one skilled in the art—in this case it was the “p recise structure of the means recited in the specification.” . . . The expert’s te stimony did not cr eate or infer the structure. 490 F.3d at 952. Aristocrat relies on a stat ement from the recent dec ision 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 “algorithm s in the specification need only disclose adequate defining structure to rend er the bounds of t he claim understandable to one of ordinary skill in the ar t.” 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 ki nd of program to use.” It is certainly true that the sufficiency of the disclosure of al gorithmic structure must be judged in light of w hat one of ordinary skill in t he 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 ‘one2007-1419 16 skilled in the art’ analysis sh ould apply in determining whet her sufficient structure has been disclosed to support a means-plus-function li mitation.”). 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 spec ificity, but whether an algorithm was disclosed at all. In Medical Instrumentation , we held that the proper inquiry for purposes of section 112 paragraph 6 analysi s is to “look at the disclosure of the patent and determine if one of skill in th e art would have understood that disclosure to encompass software [to perform the function] and been ab le to implement such a program, not simply whether one of skill in the art woul d have been able to wr ite such a software program.” 344 F.3d at 1212 (emphasis in original). We t hen 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 inqui ry 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 la cked 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 requir ed to produce a listing of s ource code or a highly detailed description of the algor ithm 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 purpose2007-1419 17 computer programmed to perform the disclosed algorithm.” WMS Gaming , 184 F.3d at 1349. Because the district co urt correctly held that was not done in this case, we uphold the judgment of the district court.
AFFIRMED

.