Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Company

PETITIONER: Festo Corporation
RESPONDENT: Shoketsu Kinzoku Kogyo Kabushiki Company
LOCATION: United States District Court Eastern District of Michigan

DOCKET NO.: 00-1543
DECIDED BY: Rehnquist Court (1986-2005)
LOWER COURT: United States Court of Appeals for the Federal Circuit

CITATION: 535 US 722 (2002)
ARGUED: Jan 08, 2002
DECIDED: May 28, 2002

Arthur I. Neustadt - Argued the cause for the respondents
Deputy Solicitor General Wallace - argued the cause for the United States as amicus curiae
Lawrence G. Wallace - Argued the cause for the United States, as amicus curiae, supporting vacatur and remand
Robert H. Bork - Argued the cause for the petitioner

Facts of the case

Festo Corporation owns two patents for an improved magnetic rodless cylinder, a piston-driven device that relies on magnets to move objects in a conveying system. When the patent examiner rejected the initial application for the first patent because of defects in description, the application was amended to add the new limitations that the device would contain a pair of one-way sealing rings and that its outer sleeve would be made of a magnetizable material. The second patent was also amended during a reexamination proceeding to add the sealing rings limitation. After Festo began selling its device, SMC entered the market with a similar device that uses one two-way sealing ring and a nonmagnetizable sleeve. Festo filed suit, claiming that SMC's device is so similar that it infringes Festo's patents under the doctrine of equivalents. Rejecting SMC's argument that the prosecution history, or the public record of the patent proceedings, estopped Festo from saying that SMC's device was similar, the District Court ruled in Festo's favor. Ultimately, the en banc Court of Appeals held that the prosecution history estoppel applied, ruling that estoppel arises from any amendment that narrows a claim to comply with the Patent Act. The Court of Appeals also held that, when estoppel applies, it bars any claim of equivalence for the element that was amended.


Does a patentee, by narrowing a claim to obtain a patent, surrender all equivalents to the amended claim element?

Media for Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Company

Audio Transcription for Oral Argument - January 08, 2002 in Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Company

Audio Transcription for Opinion Announcement - May 28, 2002 in Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Company

William H. Rehnquist:

The opinion of the Court in No. 00-1543, Festo Corporation versus Shoketsu Kinzoku Kogyo Kabushiki Limited will be announced by Justice Kennedy.

Anthony M. Kennedy:

This case involves the Patent Laws of the United States.

Festo Corporation is the petitioner in the case.

It claims that respondents whom we call SMC infringed Festo’s patents.

The Festo has two valid patents there is no doubt about that and the patents cover a conveying device that is used in certain machinery.

If you want to read about rodless cylinders that is a very interesting subject.

SMC started manufacturing and selling a similar device when Festo suit SMC for infringement, SMC said well our device is different from yours.

Festo said yes it is different but in such trivial respects, that it is an equivalent and under the Patent Laws, an equivalent device still infringes.

SMC then said the difference in your device and our device, the differences you say you are so trivial but the very difference is that you added to your claims when you amended your patent application.

You cannot amend an application in order to obtain the patent and then rely on the Doctrine of Equivalents.

The very fact that you amended the claim in question means that you are barred or in the law's term, stopped from relying on the Doctrine of Equivalents.

The Court of Appeals for the Federal Circuit agreed with SMC and in the course of granting judgment for SMC, the Court adapted a new rule, which is that once a claim is amended in the patent application process, the patent holder is stopped from relying on the Doctrine of Equivalents for any aspect of the amended claim elements, and this has come to be known as the complete bar rule.

We address two questions in this case: the first is what kind of amendments brings the stop of doctrine into play at all.

On this point, we agree with the Court of Appeals that the stop of doctrine is brought into play by amendments related to any of the law’s requirements for patent ability, not just by amendments related to the prior art.

On the second question though concerning the complete bar rule, we disagree with the Court of Appeals.

We hold that the complete bar rule is inconsistent with our previous cases and with the purpose underlying prosecution history estoppel.

To adapt it now would have set settled expectation of countless patent owners who relied on our earlier cases in amending their patents.

In the course of our opinion, we do say that when an amendment has been made to the patent application, the patent holder bares the burden of proving that the amendment was not made for a reason that would give rise to an estoppel.

This is the approach advanced to us by the United States which filed an amicus brief in the case and we regard that approach to be sound.

On the record before us, we cannot say that Festo has rebutted the presumption that the equivalents at issue have been surrendered so further proceedings are in order.

The judgment of the Court of Appeals of the Federal Circuit is reversed.

The case is remanded so that the Court of Appeals or the District Court in the first instance can determine the remaining questions.

The opinion of our court is unanimous.