Client Alert

No Coverage for Disclosed but Unclaimed Subject Matter under the Doctrine of Equivalents


On March 28, 2002, the Federal Circuit issued its en banc decision in Johnson & Johnston Associates, Inc. v. R.E. Service Co., Nos. 99-1076, -1179, -1180, 2002 WL 466547 (Fed. Cir. Mar. 28, 2002) (en banc) (per curiam). The court held that, "when a patent drafter discloses but declines to claim subject matter, . . . this action dedicates that unclaimed subject matter to the public." Accordingly, the doctrine of equivalents provides no coverage for such disclosed but unclaimed subject matter.

At issue in Johnson were claims reciting "a sheet of aluminum" and "the aluminum sheet." While the written description described the use of aluminum as the preferred embodiment, it also noted that "stainless steel or nickel alloys may be used." The trial court entered judgment on the jury's finding that the use of a steel substrate infringed under the doctrine of equivalents.

The Federal Circuit reversed. It explained that, "[h]aving disclosed without claiming the steel substrates, Johnston cannot now invoke the doctrine of equivalents to extend its aluminum limitation to encompass steel." The court noted that a patentee who inadvertently fails to claim disclosed subject matter is not without remedy, since the patentee can seek coverage of such subject matter through a reissue or continuation application.

The court's opinion resolved the conflict between Maxwell v. J. Baker, Inc., 86 F.3d 1098 (Fed. Cir. 1996), and YBM Magnex, Inc. v. International Trade Commission, 145 F.3d 1317 (Fed. Cir. 1998). Maxwell reiterated the "well-established rule that 'subject matter disclosed but not claimed in a patent application is dedicated to the public.'" 86 F.3d at 1106 (quoting Unique Concepts, Inc. v. Brown, 939 F.2d 1558, 1562-63 (Fed. Cir. 1991)). YBM purported to limit Maxwell to situations in which a patent discloses an unclaimed alternative distinct from the claimed invention.

Four judges (Clevenger, Rader, Dyk, and Lourie) filed concurring opinions, and Judge Newman dissented. Judge Clevenger clarified that the court's decision merely followed old law. Judge Rader proposed an alternative analysis for the court's decision based on a "foreseeability bar," i.e., that the doctrine of equivalents should not "capture subject matter that the patent drafter reasonably could have foreseen during the application process and included in the claims." Judge Dyk emphasized that the court's decision was not inconsistent with the Supreme Court's decision in Graver Tank & Manufacturing Co. v. Linde Air Products Co., 339 U.S. 605 (1950). Judge Lourie expressed his doubts about Judge Rader's foreseeability proposal. Finally, in her dissent, Judge Newman characterized the court's opinion as "another assault on the doctrine of equivalents" and viewed the decision as conflicting with Supreme Court and Federal Circuit precedent.

The full text of the opinion is available at




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