Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Co., LTD., et al. (535 U.S. 722)
U.S. Supreme Court · decided May 28, 2002 · Supreme Court Database (Spaeth)
- Citation
- 535 U.S. 722 · 122 S. Ct. 1831
- Decided
- May 28, 2002
- Term
- October Term 2001
- Vote
- 9–0
- Majority author
- Justice Kennedy
- Issue area
- Economic Activity
- Disposition
- Affirmed
- Outcome
- Petitioning party lost
- Ideological direction
- Conservative
Opinion excerpt
Justice Kennedy delivered the opinion of the Court. This case requires us to address once again the relation between two patent law concepts, the doctrine of equivalents and the rule of prosecution history estoppel. The Court considered the same concepts in Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U. S. 17 (1997), and reaffirmed that a patent protects its holder against efforts of copyists to evade liability for infringement by making only insubstantial changes to a patented invention. At the same time, we appreciated that by extending protection beyond the literal terms in a patent the doctrine of equivalents can create substantial uncertainty about where the patent monopoly ends. Id., at 29. If the range of equivalents is unclear, competitors may be unable to determine what is a permitted alternative to a patented invention and what is an infringing equivalent. To reduce- the uncertainty, Warner-Jenkinson acknowledged that competitors may rely on the prosecution history, the public record of the patent proceedings. In some cases the Patent and Trademark Office (PTO) may have rejected an earlier version of the patent application on the ground that a claim does not meet a statutory requirement for pat-entability. 35 U. S. C. § 132 (1994 ed., Supp. V). When the patentee responds to the rejection by narrowing his claims, this prosecution history estops him from…
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