A claim construction that excludes the preferred embodiment (by asserting that the term "brewing chamber" means a fully-enclosed space in this case) is rarely, if ever, correct and would require highly persuasive evidentiary support.
There is no precise rule or formula for deciding whether a case is exceptional [for purposes of awarding attorney's fees]. An exceptional case is “simply one that stands out from others with respect to the substantive strength of a party’s litigating position (considering both the governing law and the facts of the case) or the unreasonable manner in which the case was litigated.”
A specification adequately supports the addition of a negative limitation where the limitation is expressly disclaimed or where “independent lexicography in the written description” justifies adding it [but neither occurred in this case].
“[I]t is not appropriate for the court to construe a claim solely to exclude the accused device”. The district court thus erred by rewriting the claimed "passageway" to exclude a broad, thin mesh.
Read the case here.