Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17, 8 (1997)

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24

WARNER-JENKINSON CO. v. HILTON DAVIS CHEMICAL CO. Opinion of the Court

sion of claim scope, contrary to this Court's numerous holdings that it is the claim that defines the invention and gives notice to the public of the limits of the patent monopoly. Id., at 1537-1538 (opinion of Plager, J.). The fifth dissenter, the late Judge Nies, was able to reconcile the prohibition against enlarging the scope of claims and the doctrine of equivalents by applying the doctrine to each element of a claim, rather than to the accused product or process "overall." Id., at 1574. As she explained it: "The 'scope' is not enlarged if courts do not go beyond the substitution of equivalent elements." Ibid. All of the dissenters, however, would have found that a much narrowed doctrine of equivalents may be applied in whole or in part by the court. Id., at 1540-1542 (opinion of Plager, J.); id., at 1579 (opinion of Nies, J.).

We granted certiorari, 516 U. S. 1145 (1996), and now reverse and remand.

II

In Graver Tank we considered the application of the doctrine of equivalents to an accused chemical composition for use in welding that differed from the patented welding material by the substitution of one chemical element. 339 U. S., at 610. The substituted element did not fall within the literal terms of the patent claim, but the Court nonetheless found that the "question which thus emerges is whether the substitution [of one element for the other] . . . is a change of such substance as to make the doctrine of equivalents inapplicable; or conversely, whether under the circumstances the change was so insubstantial that the trial court's invocation of the doctrine of equivalents was justified." Ibid. The Court also described some of the considerations that go into applying the doctrine of equivalents:

"What constitutes equivalency must be determined against the context of the patent, the prior art, and the particular circumstances of the case. Equivalence, in the patent law, is not the prisoner of a formula and is

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