Prosecution History Disclaimer: Beware of What You Clearly and Unambiguously Say

Patent prosecutors typically are cautious when making arguments that distinguish their client's invention from the prior art. This caution was traditionally based on the concern that later, when the client enforced its patent rights against a potential infringer, these arguments may provide the basis for restricting the range of equivalents available to the patentee under the doctrine of prosecution history estoppel. Prosecution history estoppel normally limits the range of equivalent elements that are available to satisfy a claim element under a doctrine of equivalents analysis (<i>ie</i>, when there is no literal infringement of that claim element). Recent decisions by the Federal Circuit not only reaffirm the significance of statements made during prosecution; they also extend their impact to a literal infringement analysis. A patentee who during prosecution "clearly and unequivocally" disavows the prior art (or even defines the invention) may affect the literal scope of the claims. This doctrine is now regularly referred to as prosecution history disclaimer.

24 minute read May 01, 2004 at 04:38 PM

By

Jonathan S. Caplan And Benu Mehra