Advertisement Is the Doctrine of Equivalents (DOE) dead, once again? Effectively, yes. All an alleged infringer needs to do is raise an ensnarement defense (a claim that a DOE enlarged hypothetical claim reads on the prior art), and then show that the equivalent element was known in the prior art. Most equivalent elements (not considering … Continue reading IP Litigation: Raising an Ensnarement Defense Defeats the Doctrine of Equivalents