An express disclaimer during prosecution prevents a patentee from “attempting to recapture disclaimed subject matter by isolating and selecting individual components of the accused” product. While the result may have seemed fair in this particular case, the court’s reasoning is cause for concern, as it relies on considering “as a whole” not the claimed invention but the accused product. We have seen this before (e.g., most recently, Apple Inc. v. Samsung Elecs. Co., 695 F.3d 1370 (Fed. Cir. 2012)). The danger in this analysis is that it allows a potential infringer to escape liability by adding (often inconsequential) elements or steps to the otherwise claimed invention, thereby promoting easy design around and devaluing worthy inventions.
Background / Facts: The two patents here cover a method of applying insecticide to protect against termites, where “an effective amount of insecticide active compound is spread around or under the said building at discrete locations.” In accordance with the description in the specification, the claims require both “treated and untreated locations along the perimeter of the building” instead of a continuous barrier without loopholes. During prosecution, the patentee filed an expert declaration asserting that “the teaching of the common general knowledge and prior art as of [the filing of the application] directs the skilled artisan to make a barrier treatment of chemical insecticide around a structure … i.e., [having] no untreated locations.” The accused insecticide product instructs its user to apply insecticide around a building to form a barrier, but then also to also apply the insecticide inside the building only at discrete locations.
Issue(s): Whether the disclaimer of barrier treatments extends to products that use barrier treatments in combination with discrete treatments.
Holding(s): Yes. “Because [the] accused product instructs application of a complete barrier around a building, it falls within the scope of Kimura’s disclaimer.” The patentee “may not now attempt to recapture disclaimed subject matter by isolating and selecting individual components of the accused method, which as a whole reaches the very result that [the patentee] expressly disclaimed.” Thus, “[b]ecause Kimura expressly disclaimed insecticide treatments that form a complete barrier around or under a building, and because MANA’s accused product require a complete barrier around a building, MANA’s product cannot infringe the Kimura patents.”