Addressing the doctrine of equivalents, the U.S. Court of Appeals for the Federal Circuit reversed summary judgment finding of no equivalence, concluding that a genuine issue of material fact existed as to whether a capacitor located within a circuit was equivalent to a patent limitation that the capacitor be "operatively disposed in parallel" to the circuit under the "function-way-result" test. Brilliant Instruments, Inc. v. GuideTech, LLC, Case No. 12-1018 (Fed. Cir., Feb. 20, 2013) (Moore, J.) (Dyk, J., concurring in part and dissenting in part).

The district court granted declaratory judgment in favor of Brilliant Instruments, finding no infringement of three U.S. patents directed to circuits measuring digital signal timing errors in high-speed microprocessors. Reviewing the summary judgment decision de novo pursuant to regional Ninth Circuit law, the Federal Circuit found from the record that the "One-Channel-Two-Edge mode" of Brilliant's accused products raised a genuine issue of material fact regarding whether two measurement circuits were contained within a signal channel.

Reviewing literal infringement of two of the asserted patents, the Federal Circuit agreed with the district court that there was no literal infringement, reasoning that because the capacitor in question was conceded by GuideTech to be part of the "first current circuit," it could not be "on an alternative path on which current flows from the first current circuit," and therefore did not meet the representative "operatively disposed in parallel" limitation.

In examining infringement under a doctrine of equivalents theory, however, the Federal Circuit found that GuideTech had raised a genuine issue of material fact. Addressing Brilliant's argument that GuideTech's infringement theory under the doctrine of equivalents would "vitiate" the requirement that the claimed "first current circuit" and the "capacitor" are separate elements, the Court first reiterated that "vitiation" is not an exception to the doctrine of equivalents, but a legal determination that no reasonable jury could determine the elements to be equivalent. Vitiation cannot be established by noting that an element is missing from the claimed structure or process, because, by definition, the doctrine of equivalents recognizes that an element is missing that must be supplied by an equivalent substitute. The Federal Circuit concluded that summary judgment of noninfringement under the doctrine of equivalents was not appropriate, because GuideTech had created a genuine issue of material fact regarding whether Brilliant's capacitor, even while located within the first current circuit, performed substantially the same function in substantially the same way to achieve substantially the same result as the claimed capacitor, which is "operatively disposed in parallel to the shunt."

In a separate opinion, Judge Dyk concurred with the majority except with respect to whether a genuine issue of material fact remained as to infringement under the doctrine of equivalents. Highlighting that application of the doctrine of equivalents requires application on a limitation-by-limitation basis, Judge Dyk found that GuideTech's expert had offered analysis of only the equivalence of the invention as a whole and failed specifically to set forth facts explaining why a capacitor in the accused device located inside the first current circuit, and not outside, was insubstantial.

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