Doctrine of equivalents in US and European patent law

Lawsuits for patent infringement require a showing that an accused product or process includes each and every element of an asserted claim, write Jonathan Roses (pictured, left) counsel, Wolf, Greenfield & Sacks, and Alexander Lee, associate, Hoffmann Eitle, in an Expert View piece.

While infringement is generally demonstrated by showing that each limitation is literally present, there are certain circumstances in which courts will find infringement based on accused products or processes that do not literally contain each and every claim element.

In these situations, the Doctrine of Equivalents (DOE) will allow for extension of the asserted claim beyond its literal scope. This article discusses the differential application of DOE in the USA and across Europe.