Primos v. Hunter’s Specialties (Fed. Cir. 2006, 05–1001).
Primos owns patents on game calls for hunting. In an infringement suit, a jury found that Hunter’s products literally infringed one patent and infringed another under the doctrine of equivalents (DOE).
On appeal, Hunter challenged the DOE decision arguing both (1) Festo Estoppel and (2) Vitiation. In a surprise boost to the DOE, the CAFC affirmed — finding that the DOE could be asserted.
Estoppel: Hunger argued that a claim amendment made during prosecution created an estoppel that, under Festo, prevented assertion of the DOE. Primos countered that Festo estoppel should not apply because the “amendment bears no more than a tangential relationship to the accused element.”
As the Supreme Court explained in Festo, when a patent claim is amended during prosecution for reasons relating to patentability, there is a presumption that the patentee surrendered all the territory between the original claim limitation and the amended claim limitation. 535 U.S. at 740. There are situations, however, in which a patentee may overcome that presumption. Id. One such situation is when the "rationale underlying the amendment may bear no more than a tangential relation to the equivalent in question." Id. at 740-41.
Here, Primos had twice amended the claim to: (1) require that the “plate” have “a length” and (2) require that the plate be “differentially spaced” above the membrane. Because “every physical object has a length,” the first amendment did not narrow the scope of the claim. The accused product included a differentially spaced dome rather than a differentially spaced plate as claimed. “Because the accused device’s dome includes the spacing, the amendment was merely tangential to the contested element in the accused device, and thus prosecution history estoppel does not apply to prevent the application of the doctrine of equivalents.”
Thus, this holding implies that Festo estoppel does not apply when the newly added limitation (or term) is found in the accused product.
Vitiation: The Court had streak expanding the vitiation doctrine under the all-elements rule. Here, Hunter asserted that allowing a "dome" to be considered an equivalent to a "plate" would eliminate (or vitiate) that limitation from the claim. The CAFC balked at Hunter’s implicit suggestion that there might be no equivalent for the claimed plate:
Our precedent has recognized that "[t]here is no set formula for determining whether a finding of equivalence would vitiate a claim limitation, and thereby violate the all limitations rule. Rather, courts must consider the totality of the circumstances of each case and determine whether the alleged equivalent can be fairly characterized as an insubstantial change from the claimed subject matter without rendering the pertinent limitation meaningless." Thus, because Primos’s theory of equivalence (i.e., that a dome is equivalent to the claimed "plate") does not "effectively eliminate . . . [the ‘plate’ limitation] in its entirety," it does not violate the all limitations rule.
This case is in line with my alternate theory that vitiation only applies to linkages and noun modifiers.
Freedman Seating: Vitiation of the Doctrine of Equivalents;