Implied License by Equitable Estoppel Law and Legal Definition

Equitable estoppel employs a different theory to arrive at an implied patent license. Implied license by equitable estoppel is an implied license that is normally based on the patentee’s failure to take timely action to enforce patent rights against an infringer after objecting to the infringer’s actions, by misleading the infringer to believe that eh patentee will not act.

Equitable estoppel requires that the patentee communicate to the accused infringer in some manner its intent not to sue, that the infringer rely on this communication, and that allowing the patentee to proceed with its claim would materially prejudice the alleged infringer.