What Territory Is Surrendered

551 IN NOVEMBER 2000, the Court of Appeals for the Federal Circuit issued an opinion1 concerning two sometimes-competing concepts in patent law: the doctrine that the scope of patent claims may sometimes be limited by statements made by an applicant during prosecution, known as “prosecution history estoppel”; and the concept that patent claims may sometimes be interpreted to include embodiments beyond the literal scope of the claims, known as the “doctrine of equivalents.” This decision, which held that a narrowing amendment made to a claim element during prosecution surrenders all equivalents to that element, created a great deal of anxiety amongst both patentees and intellectual property practitioners, as it seemed to penalize the sort of give-and-take between applicants and patent examiners regarding claim language typically seen during patent prosecution. Given the number of words spent in analyzing (and criticizing) the CAFC’s decision, it was with some relief that we saw the Supreme Court grant certiorari to reconsider the issues involved. The Supreme Court has now spoken, and many more words will no doubt be spent in analyzing this decision as well. While the high court disagreed with the CAFC, it is unclear how much clarity the Supreme Court has brought to this vexing problem. The goal of this paper is to examine the guidance given in the decision, point out issues of likely contention, and provide hypothetical cases that test the boundaries of the decision. AN OVERVIEW OF THE GUIDANCE PROVIDED BY THE SUPREME COURT FOR DETERMININGWHEN EQUIVALENTS ARE NOT SURRENDERED BY A CLAIM AMENDMENT