Law Commons^™

Patent Drafter Estoppel: Why Didn't Sage Products Create A New Foreseeability Limitation On The Application Of The Doctrine Of Equivalents?, Christopher M. Kaiser

ExpressO

This article reviews the 1997 Federal Circuit Case of Sage Products v. Devon and the case law that has followed it. There is some belief among patent practitioners that Sage Products created a new legal doctrine limiting the application of the doctrine of equivalents in patent infringement cases. The new doctrine, sometimes referred to as “patent drafter estoppel,” would bar the application of the doctrine of equivalents any time an accused equivalent structure should have been foreseen by a reasonable patentee. Federal Circuit case law since Sage Products has diverged into two lines of thought: one that supports the thinking …