Computer-implemented means-plus-function claim invalid when no algorithm disclosed in specificationMarch 31, 2008

In a decision Friday, the Federal Circuit affirmed a final judgment of invalidity of all claims of a patent indefinite. The claims had several means-plus-function clauses that were computer-implemented, however no algorithms for implementing the claimed functions were disclosed in the specification. The district court held the claims invalid because there was no "structure" (i.e., algorithm) disclosed in the specification corresponding to the means-plus-function clauses.The Federal Circuit affirmed, noting that when a means-plus-function clause is computer-implemented, there must be at least one example in the specification of an algorithm performing the function in order to meet the requirements of 35 U.S.C. § 112 ¶ 6 . Without such an example, what is left is purely functional claim language, which is impermissible under the statute.

Likewise, it is insufficient to argue that one of ordinary skill in the art would be able to implement the method. While that may solve any § 112 ¶ 1 enablement concerns, it does not meet the statutory requirement of a disclosure of "structure" in § 112 ¶ 6. As a result, the claims were held invalid as indefinite.More detail of Aristocrat Techs. Austl. Pty Ltd. v. Int'l Game Tech. after the jump.

Aristocrat Technologies ("Aristocrat") brought an infringement action against International Game Technology for infringement of a patent directed to "an electronic slot machine that allows a player to select winning combinations of symbol positions."The key issue before the district court was the definiteness of the claim limitation "game control means" or "control means" used throughout the claims. The district court noted the "game control means" performed 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 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 parties agreed the claims invoked § 112 ¶ 6, and they stood or fell together on the issue of indefiniteness. Aristocrat argued the structure corresponding to the function performed by the "control means" was "a standard microprocessor-based gaming machine with 'appropriate programming.'" The district court noted "the specification contained no guidance to determine the meaning of 'standard microprocessor' or 'appropriate programming.'" The district court further noted where "the disclosed structure is a computer or a microprocessor 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.'" Noting that the specification lacked such disclosure, the district court held the patent did not satisfy the requirements of § 112 ¶ 6, and was invalid as indefinite.The Federal Circuit affirmed. The court noted that it "has consistently required that the structure disclosed in the specification be more than simply a general purpose computer or microprocessor" and that "[f]or 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." Further, the Federal Circuit noted that "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." The Federal Circuit rejected Aristocrat's argument that the claims implicitly disclosed an algorithm for the microprocessor, noting that 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." The court reiterated that this assertion is contrary to Federal Circuit case law. Further, the court noted that the examples pointed to by Aristocrat are not descriptions of the computer programmed to execute the particular algorithm, but rather descriptions of the outcomes of claimed functions. The Federal Circuit upheld the district court's conclusion that Aristocrat's claims did not meet the requirements of § 112 ¶ 6. The Federal Circuit cited Aristocrat's argument 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 the claim" as telling evidence that "Aristocrat is in essence arguing for pure functional claiming as long as the function is performed by a general purpose computer." As a result of this lack of disclosure, the court affirmed the finding of invalidity because of indefiniteness.To read the full decision in Aristocrat Techs. Austl. Pty Ltd. v. Int'l Game Tech., click here.

← Return to Filewrapper

Stay in Touch

Receive the latest news and updates from us and our attorneys.

Sign Up