Vacating a grant of summary judgment of non-infringement, a divided U.S. Court of Appeals for the Federal Circuit determined that a district court had erred in construing the claim term "aesthetic correction circuitry" as a means-plus-function limitation under § 112 ¶6 and held that the term "circuitry" together with a description of the operation of the circuit was sufficient to avoid §112 ¶6. Massachusetts Institute of Technology v. Abacus Software, Case No. 05-1142 (Fed. Cir., Sept. 13, 2006) (Dyk, J.; Michel, J., dissenting).
The claim in issue related to a color processing system that produced copies of color originals by scanning an original color image, interactively editing the scanned image and selecting colorants to generate a reproduction of the original image. One of the disputed claim terms was "aesthetic correction circuitry," whose recited function was "interactively introducing aesthetically desired alterations into said appearance signals to produce modified appearance signals." Another disputed claim term was "colorant selection mechanism," for which the recited functions were "receiving said modified appearance signals" and "selecting corresponding reproduction signals." Although neither term included the word "means," in the district court’s view the presumption against means-plus-function treatment under § 112 ¶6 was overcome for both terms because of the failure in both cases to recite a sufficiently definite structure.
According to the panel majority, the district court properly construed the term "colorant selection mechanism" as a means-plus-function limitation, but erred in holding that the presumption against § 112 ¶6 treatment was overcome for the term "aesthetic correction circuitry." Relying on dictionary definitions and Federal Circuit precedent, the Court concluded that the term "aesthetic correction circuitry" connoted sufficient structure to avoid treatment as a "means-plus-function" limitation, whereas the term "colorant selection mechanism" did not connote sufficient structure to avoid § 112 ¶6 treatment. Observing that the patentee had used the words "mechanism" and "means" as synonyms and quoting a dictionary definition that equated "mechanism" with "means," the Court determined that a generic term such as "mechanism," standing alone, did not connote any more structure than the term "means." In contrast, the Court found that dictionary definitions established that the term "circuitry" by itself connoted structure. Citing Linear Technology and Apex as precedent, the Court held that the term "circuit," combined with a description of the function of the circuit, connoted sufficient structure to one of ordinary skill in the art to avoid § 112 ¶6 treatment, because the claim language added further structure to the term "circuit" by describing the operation of the circuit. The Court reasoned that the claim limitation at hand recited a circuit having "appearance signals" as input, "modified appearance signals" as output, and which operated by "interactively introducing aesthetically desired alterations into said appearance signals." In the eyes of the Court, such description of the operation of the circuit was sufficient to avoid § 112 ¶6. In a 15-page dissent Chief Judge Michel argued that, in view of its specific language, "aesthetic correction circuitry" was correctly construed as a means-plus-function claim limitation and accused the majority of misapplying the cited precedent.
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