Broadest Reasonable Interpretation and Appellate Review

In this essay, I examine the meaning of "broadest reasonable interpretation" along two dimensions: how it affects the Federal Circuit's review of Patent Office claim constructions and what it seems to mean in substantive terms. Central to both is the term "reasonable." How should that term be understood? Does it mean that the Federal Circuit grants deference to the Patent Office when reviewing its constructions, as some commentators describe and some opinions suggest? And, perhaps more importantly, what is a "broadest reasonable interpretation" and how does that fit into the process of claim construction generally?Here, I argue that regardless of one's view on the historical nature of judicial review of Patent Office claim interpretation, any deference is inconsistent with the Federal Circuit's use of a de novo standard when reviewing claim interpretations by the Patent Office (with the exception of findings of fact relating to extrinsic evidence). Second, I argue that the still-developing jurisprudence at the Federal Circuit is coalescing around a meaning of "broadest reasonable interpretation" that allows for the existence of multiple ordinary meanings and reads the intrinsic evidence with a certain degree of "looseness," but which is still hesitant to embrace ambiguity within the application of the tools of claim construction.