Recent Federal Circuit Case Sheds Light on Use of the Defense of RDOE and DOE application in view of a Stipulated Contrary Claim Construction 

The Federal Circuit’s recent decision in Steuben Foods, Inc. (Steuben Foods) v. SHIBUYA HOPPMANN CORPORATION, SHIBUYA KOGYO CO., LTD., HP HOOD LLC (Shibuya)[1] provides useful guidance for patent practitioners seeking to invoke the rarely-applied defense of the reverse doctrine of equivalents (RDOE) and/or apply the doctrine of equivalents (DOE) in view of a stipulated contrary claim construction.

Steuben Foods, the owner of U.S. Patent Nos. 6,209,591 (the ‘591 patent), 6,536,188 (the ‘188 patent), and 6,702,985 (the ‘985 patent) appeals the district court’s entries of judgment as a matter of law (JMOL) of noninfringement.”[2] The patents at issue are related to aseptic packaging of food products.

The Defense of RDOE

The  ‘591 patent dispute centered around  RDOE. An alleged infringer may avoid a judgment of infringement under RDOE by showing the accused “product has been so far changed in principle [from the asserted claims] that it performs the same or similar function in a substantially different way.”[3] If a patentee meets its initial burden of establishing literal infringement, an accused infringer bears the burden of establishing a prima facie case of noninfringement under RDOE.[4] If the accused infringer meets this burden, then the burden shifts back to the patentee to rebut the prima facie case.[5] In this case, after the jury found claim 26 of the ’591 patent not invalid and infringed, the district court found that Shibuya satisfied its prima facie case of RDOE through expert testimony.[6] Although Steuben Foods presented rebuttal expert testimony, the district court found that such rebuttal testimony was wrong as a matter of law and entitled to no weight.[7]

On appeal, Steuben Foods argues that RDOE is not a viable defense to infringement because it was eliminated by the 1952 Patent Act.[8] Steuben argues the plain language of 35 U.S.C. § 271(a), “[e]xcept as otherwise provided in this title,” requires that exceptions to infringement must be expressly identified in Title 35.[9] Because RDOE is not codified in Title 35, Steuben argues it is no longer a defense to infringement.[10] Specifically, Steuben argues that if a device literally falls within the scope of a claim, but the accused infringer believes the claim is too broad and its device should not infringe, the appropriate recourse is a § 112 challenge, not a claim of noninfringement under RDOE.[11]

Although the Federal Circuit hinted that Steuben Food’s arguments may be compelling,[12] the court did not decide the issue of whether RDOE survived 1952 Patent Act. Rather, the Federal Court held that the finding of JMOL was improper because the jury was entitled to credit Steuben Food’s rebuttal testimony and find infringement.[13]

DOE application of means plus function limitation

The dispute with respect to the ‘188 patent centered around the application of DOE to a means plus function claim limitation (“means for filling the aseptically disinfected plurality of bottles at a rate greater than 100 bottles per minute”). The district court granted JMOL of noninfringement. Although Steuben Foods presented expert testimony to the jury in an attempt to show that the accused structures perform the claimed function in an equivalent way, the district court held that no reasonable juror could find “the way the accused machines’ rotary wheels and neck grippers operate is substantially the same as the way a conveyor and conveyor plate operate.”[14]

On appeal, Steuben Foods argues that the district court failed to consider infringement in the context of the claimed function and erred by importing unclaimed functions into its analysis.[15] Again, the Federal Court agreed with Steuben Foods and held that the finding of JMOL was improper because the jury was entitled to credit the expert testimony and find infringement.[16]

DOE limited by stipulated contrary claim construction

Lastly, the dispute with respect to the ‘985 patent centered around the claim term “intermittently” and application of DOE thereto. Both parties stipulated to a claim construction of “intermittently added” as “[a]dded in a non-continuous matter” and it was undisputed the accused machines add sterilant continuously.[17] The jury found claims 3 and 7 of the ’985 patent infringed under DOE.[18] The district court granted Shibuya’s motion for JMOL of noninfringement, determining that the “‘intermittently added’ limitation cannot be met under DOE by a continuous addition of sterilant,” because “intermittently” and “continuously” are antonyms of each other, not equivalents, and doing something in a noncontinuous manner cannot be achieved by doing it continuously.[19]

On appeal, Steuben Foods argues that the district court erred because expert testimony was presented that under DOE, the accused product’s continuous sterilization is equivalent to the claimed “intermittently added” limitation and thus the jury’s finding of infringement was reasonable.[20] On this third patent, the Federal Circuit affirmed the district court’s grant of JMOL of noninfringement in favor of Shibuya.[21] The Federal Circuit seemingly was persuaded by the fact that both parties stipulated to the claim construction of “intermittently added” as “[a]dded in a noncontinuous matter,” finding of infringement under DOE would vitiate the claim limitation.[22]

The Steuben Foods decision illustrates that – at least for now – the RDOE is still a viable defense, as the Federal Circuit has not yet addressed whether it was eliminated by the 1952 Patent Act. The Steuben Foods decision further illustrates that when stipulating to a claim construction during litigation, patent practitioners should take care to avoid agreeing to a definition that may limit application of the DOE.

[1] Steuben Foods, Inc. v. Shibuya Hoppmann Corporation, Shibuya Kogyo Co., Ltd., HP Hood LLC, 2023-1790, Fed. Cir., January 24, 2025.
[2] Id. at page 2.
[3] Id. at page 7.
[4] Id.
[5] Id.
[6] Id.
[7] Id.
[8] Id. at page 9.
[9] Id.
[10] Id.
[11] Id. at pages 9-10.
[12] Id. at page 10.
[13] Id. at pages 10-12.
[14] Id. at pages 14-15.
[15] Id. at page 15.
[16] Id.
[17] Id. Id at page 18.
[18] Id.
[19] Id.
[20] Id.
[21] Id. at page 20.
[22] Id. at page 19.