The Doctrine of Equivalents Lives—U.S. Supreme Court Reverses Federal Court

In a major decision that will have far-reaching impact on issues of infringement of U.S. patents, the U.S. Supreme Court, in overruling the U.S. Court of Appeals for the Federal Circuit in the Festo case, ruled that the doctrine of equivalents should be applied in a flexible manner. This strengthens the patent owner’s position. The appellate court ruled that any narrowing of a recital of a claim element absolutely barred use of the doctrine of equivalents as to that element.

A U.S. patent contains one or more patent claims that define the scope of the property provided by the claim. There are two ways in which one can directly infringe a claim. First, if one satisfies every recital of the claim, such infringement is termed “literal infringement”. Second, under the judicially created doctrine of equivalents, if one makes a minor departure from the claim and, therefore, does not literally infringe, one may nevertheless be held to be an infringer if one achieves substantially the same function in substantially the same way to obtain substantially the same result. This results from an equitable balancing of interests, leading to the conclusion that one who makes an insubstantial change should not be permitted to obtain the benefit of the invention while avoiding infringement.

One manner in which the applicability of the doctrine of equivalents is restricted or eliminated occurs when an original claim is narrowed by amendment during prosecution to avoid prior art. The general concept is that one who has surrendered coverage has made a deal with the Patent and Trademark Office to obtain a patent and cannot later recapture that surrendered coverage under the doctrine of equivalents.

A patent application is required by Section 112 of the statute to have claims that particularly point out and distinctly claim the subject matter of the invention. Under the Festo case, the Supreme Court made it clear that a response to a rejection, based upon indefiniteness in the context of such Section 112 requirements, may lead to a narrowing of the claim to satisfy Section 112 and thereby also restrict the availability of the doctrine of equivalents. The focus is whether the amendments were made for a substantial reason related to patentability.

Such changes made during the prosecution of the application are generally referred to as involving prosecution history estoppel.

In the Festo case the patent examiner entered a rejection under Section 112. The applicants added limitations to the claims. Subsequently, the alleged infringer made a similar device. The Supreme Court remanded the case to the Circuit to determine whether prosecution history estoppel, through the amendments made by Festo, precluded its asserting the doctrine of equivalents as a basis for alleging that the third party’s device infringed.

Under the Federal Court opinion, which was reversed by a unanimous Supreme Court, the rigid bar would have stated that, as two elements in question were the subject of narrowing amendments, the doctrine of equivalents could not be employed and, therefore, there would be no infringement. Under the U.S. Supreme Court’s ruling that the standard should be as it had been previously, a flexible bar, the court stated that the coverage surrendered by the narrowing amendment could not be recaptured, but there could be remaining equivalents as to the narrowed language. The burden is on Festo, under the flexible bar standard considering the purpose of the amendments, to prove that it retained sufficient equivalents to embrace the third-party product. Part of what is considered in evaluating this issue is that, at the time of drafting the narrowed limitation, one could not anticipate creating such precise language in the description that no one could devise an equivalent. Further, there is no reason why even a precisely worded narrowing amendment should be deemed to relinquish equivalents which were unforeseeable at the time of the amendment and were beyond any reasonable interpretation of what was surrendered in narrowing the claim.

The Supreme Court also went on to note that, under law prior to the Court of Appeals’ ruling in the Festo case, the settled law involved the flexible bar in applying the doctrine of equivalents. The court conceded that a bright-line rule could not be adopted. On the other hand, as to the large number of patents that were prosecuted under the prior law, with the understanding that a flexible bar rule would apply to the doctrine of equivalents, many applicants would have prosecuted their applications differently had they understood that a rigid bar precluding any application of the doctrine of equivalents as to an amended element were to be employed. For example, rather than amending a claim to narrow the claim, the applicant had the right to appeal the rejection.

This clearly strengthens the position of the patent owner and creates greater flexibility in the prosecution of patent applications.

For more information, contact A.B. Silverman at Eckert Seamans Cherin & Mellott, LLC, 600 Grant Street, 44th Floor, Pittsburgh, Pennsylvania 15219; (412) 566-2077; fax (412) 566-6099; e-mail abs@escm.com.