Today, February 20, 2013, in Brilliant Instruments, Inc. v. GuideTech, Inc., No. 2012-1018, the Federal Circuit (Dyk (dissenting-in-part), Moore, and Reyna) reversed the Northern District of California’s prior grant of summary judgment of no infringement under the doctrine of equivalents based on fact issues regarding whether a capacitor that was “part of” a first circuit is equivalent to the claim limitation of a capacitor “disposed in parallel” to the first circuit.  This case provides incremental guidance on a common infringement issue, where claim language provides structural relationships between components and litigators argue whether the claim covers an accused device having a different structural relationship—e.g., whether covering the accused structure would “vitiate” the claim limitation.

The claims at issue required a capacitor that is “operatively disposed in parallel” with respect to a first current circuit.  The accused products, however, included a capacitor as a component within the first circuit.   Because the accused capacitor of the accused products fell outside the literal scope of the claims, the Federal Circuit affirmed the district’s court finding of no literal infringement.

But the court reversed on the doctrine of equivalents.  The patentee’s expert had provided an infringement analysis under the function-way-result test, asserting that:

The electrical disposition of the shunt and the capacitor with respect to the first current circuit of the [accused device] is equivalent to the electrical disposition of the shunt and the capacitor with respect to the first current circuit of this claim limitation because it performs substantially the same function (allowing the shunt to control the path of current flow to or from the first current circuit) in substantially the same way (wherein an electrical path from the first current circuit can be traced to either the capacitor or the shunt) to achieve substantially the same result (providing an electrical relationship wherein, e.g., the shunt can direct current to flow from the first current circuit to the second current circuit or from the first current circuit to the capacitor). (emphasis added)

The Federal Circuit ruled that this “detailed application of the function-way-result test” created a genuine issue of material fact regarding equivalence that a jury should resolve.

While the accused infringer argued that the expert’s theory would vitiate the claim language regarding the capacitor, the Federal Circuit found this to be an overbroad reading of the vitiation concept:

The vitiation test cannot be satisfied merely by noting that the equivalent substitute is outside the claimed limitation’s literal scope.  Rather, vitiation applies when one of skill in the art would understand that the literal and substitute limitations are not interchangeable, not insubstantially different, and when they do not perform substantially the same function in substantially the same way, to accomplish substantially the same result.  In short, saying that a claim element would be vitiated is akin to saying that there is no equivalent to the claim element in the accused device based on the well-established “function-way-result” or “insubstantial differences” tests.

In dissent, Judge Dyk asserted that the majority improperly applied the function-way-result test to the invention as a whole, instead of on a limitation-by-limitation basis.