By Dennis Crouch
When I wrote about the Doctrine of Equivalents (DOE) yesterday, I made a mental note that the Federal Circuit has not decided many DOE cases recently. To confirm this notion, I searched Westlaw for all Federal Circuit decisions that mention the “Doctrine of Equivalents.” Those results are presented below:
- Of course, a decision's mention of the words "doctrine of equivalents" does not suggest that the appellate decision involved the DOE. However, the majority of these cases did at least involve allegations of infringement under the DOE.
- The rise in the late 1990’s and early 2000’s revolves around Festo.
- For the past decade, the number of Federal Circuit patent infringement appeals has remained relatively steady.
- To find the number of reported patent decisions, I searched Westlaw’s database of Federal Circuit decisions for the terms “patent /2 (infring! valid! invalid! obvious!)”.
- These results continue the trends discussed in Allison & Lemley’s 2007 article “The (Unnoticed) Demise of the Doctrine of Equivalents.” and Lee Petherbridge’s excellent 2008 article “The Claim Construction Effect.”