Claiming a software invention as part of a system or apparatus, and using means-plus-function language to define a software element, requires that the patent specification describe the algorithm for performing the specified function.
U.S. software patent law has recently changed. Aristocrat Technologies Australia PTY Ltd. v. International Game Technology, 521 F.3d 1328, 1333 (Fed. Cir. 2008).
The Aristocrat case involved a patent for an electronic slot machine which allows users to define the winning symbol combination before commencing the game. The invention used a computer processor to control how the game functioned.
The sole independent claim of the patent recited a “game control means” using means-plus-function language. The claim recited a means for performing a specified function without reciting the structure for performing the function.
The patent specification stated it was within the capability of a worker in the art “to introduce the methodology on any standard microprocessor base[d] gaming machine by means of appropriate programming.”
The CAFC held that the independent claim and all other dependent claims were invalid because it was not “definite” as required by the Patent Act, 35 USC section 112, paragraph 2.
Since the claim used means-plus-function language, the court inquired whether Aristocrat sufficiently disclosed the structure of the “game control means.”
Aristocrat contended its disclosure of a “standard microprocessor” with “appropriate programming” sufficed. The CAFC rejected Aristocrat’s arguments because it “has consistently required that the structure disclosed in the specification be more than simply a general purpose computer or microprocessor.” 521 F.3d at 1333.
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.” Id.
Patents must disclose the particular algorithm that a computer uses to execute a function in order to avoid “pure functional claiming.”
The court also rejected Aristocrat’s view that disclosure of “a microprocessor with ‘appropriate programming’” sufficed because a skilled person could devise an appropriate algorithm. According to the CAFC, “the pertinent question . . . is whether Aristocrat’s patent discloses structure that is used to perform the claimed function.” Id. at
1336.
While the sufficiency of such disclosures should be judged from the viewpoint of a person skilled in the art, an algorithm must still be disclosed. For software patent drafters, the issue is whether the patent specification itself discloses a software algorithm. If so, then a means-plus-function element is limited to software programs using such an algorithm. If not, such claims are invalid for indefiniteness – even if a person of ordinary skill could write appropriate software.
The patent application needs to disclose source code or even a “highly detailed description of the algorithm.” Aristocrat, 521 F.3d at 1338.
If means-plus-function language is used, the patent application must “at least disclose the algorithm that transforms the general purpose microprocessor to a special purpose computer programmed to perform the disclosed algorithm.”
This may be accomplished by using detailed flowcharts and written descriptions.
The only alternatives are: 1) avoid invoking the requirement for describing an algorithm; or 2) using instead a method claim to define an invention.
Only in the most unusual cases would section 112, paragraph 6 be applied to method claims.
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