IP News

On September 26, 2003, an en banc panel of the Federal Circuit decided Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd, 2003 U.S. App LEXIS 19867 (Fed. Cir. 2003), which was on remand from the Supreme Court. The sole issue on remand was whether Festo could rebut the presumption that it had surrendered all of the subject matter between the original claim limitations and the amended limitations. The Supreme Court vacated the Federal Circuit's earlier en banc decision that no range of equivalents was available for the amended claims and ruled that a narrowing amendment presented a rebuttable presumption that all of the territory between the original and amended language had been surrendered. The Supreme Court also enumerated three ways in which a patentee could overcome that presumption: 1) that the equivalent was unforeseeable at the time of the amendment; 2) that the rationale underlying the amendment was only tangentially related to the equivalent in question, or 3) that there was some other reason that the patentee could not be reasonably expected to have described the substitute.

The Federal Circuit discussed the en banc holdings that were undisturbed by the Supreme Court's ruling. First, a narrowing amendment made to comply with any provision of the Patent Act could invoke estoppel. Second, a voluntary amendment could give rise to estoppel. Third, a narrowing amendment was presumably made for patentability purposes unless the record revealed a different reason for the amendment.