View source for Warner-Jenkinson Company v. Hilton Davis Chemical Co., 520 US 17 (1997) Notes

Supreme Court of the United States

doctrine of equivalents upheld

*dye purification
*one makes process at pH 6-9, other at pH 5, same thing

(c) The determination of equivalence should be applied as an objective inquiry on an element-by-element basis. The Court is concerned that the doctrine, as it has come to be broadly applied since Graver Tank, conflicts with the Court's numerous holdings that a patent may not be enlarged beyond the scope of its claims. The way to reconcile the two lines of authority is to apply the doctrine to each of the individual elements of a claim, rather than to the accused product or process as a whole. Doing so will preserve some meaning for each of a claim's elements, all of which are deemed material to defining the invention's scope. So long as the doctrine does not encroach beyond these limits, or beyond related limits discussed in the Court's opinion, infra, at 1049-1051, 1053-1054, n. 8, and 1054, it will not vitiate the central functions of patent claims to define the invention and to notify the public of the patent's scope. Pp. 1048-1049.

(e) The Court rejects petitioner's argument that Graver Tank requires judicial exploration of the intent of the alleged infringer or a case's other equities before allowing application of the doctrine of equivalents. Although Graver Tank certainly leaves room for the inclusion of intent-based elements in the doctrine, the Court does not read the case as requiring proof of intent. The better view, and the one consistent with Graver Tank's predecessors, see, e.g., Winans v. Denmead, 15 How. 330, 343, 14 L.Ed. 717, and the objective approach to infringement, is that intent plays no role in the doctrine's application. Pp. 1051-1052.

why was first patent (6-9) not found equivalent?

HD sues WJ for infringement.

“What constitutes equivalency must be determined against the context of the patent, the prior art, and the particular circumstances of the case.

Consideration must be given to the purpose for which an ingredient is used in a patent, the qualities it has when combined with the other ingredients, and the function which it is intended to perform. An important factor is whether persons reasonably skilled in the art would have known of the interchangeability of an ingredient not contained in the patent with one that was.

Petitioner's primary argument in this Court is that the doctrine of equivalents, as set out in Graver Tank in 1950, did not survive the 1952 revision of the Patent Act, 35 U.S.C. § 100 et seq., because it is inconsistent with several aspects of that Act

 The various policy arguments now made by both sides are thus best addressed to Congress, not this Court.

We concur with this apt reconciliation of our two lines of precedent. Each element contained in a patent claim is deemed material to defining the scope of the patented invention, and thus the doctrine of equivalents must be applied to individual elements of the claim, not to the invention as a whole.

 we think the better rule is to place the burden on the patent holder to establish the reason for an amendment required during patent prosecution. The court then would decide whether that reason is sufficient to overcome prosecution history estoppel as a bar to application of the doctrine of equivalents to the element added by that amendment.


goes back to trial ct, have to prove ph 6 was not important to show that 5 was basically equivalent