The US Court of Appeals for the Federal Circuit ruled that the “substantially the same way” comparison in connection with a doctrine of equivalents (DOE) analysis involving a means-plus-function claim limitation should focus on the overall structure corresponding to the claimed function, not on unclaimed structure. Steuben Foods, Inc. v. Shibuya Hoppmann Corp., Case No. 23-1790 (Fed. Cir. Jan. 24, 2025) (Moore, Hughes, Cunningham, JJ.)

Steuben Foods holds patents for an aseptic bottling system designed to sterilize and fill bottles with foodstuffs at speeds exceeding 100 bottles per minute, making the technology suitable for high-volume food production. Steuben sued Shibuya for infringing its patents. At trial, Steuben successfully demonstrated that Shibuya’s aseptic bottling system infringed a patent claim related to a “second sterile region,” a feature designed to pre-sterilize a valve mechanism and prevent contamination. The jury awarded Steuben more than $38 million in damages and, in doing so, rejected Shibuya’s defense under the reverse doctrine of equivalents (RDOE). The RDOE is a rarely invoked defense that is asserted when an accused product, although meeting the literal terms of a claim, operates on fundamentally different principles and thus does not infringe. Despite the jury’s verdict, the district court granted judgment as a matter of law (JMOL) of noninfringement, holding that Shibuya’s RDOE defense precluded infringement. Steuben appealed.

The Federal Circuit reversed the JMOL based on the RDOE, finding that the district court improperly weighed evidence that should have been left to the jury. The Court emphasized that Steuben’s expert testimony constituted substantial evidence supporting the jury’s findings and warranted deference. The Court also rejected Shibuya’s narrow construction of the claimed “second sterile region,” which would have excluded food flow, and affirmed the broader interpretation adopted by the district court (an interpretation the Court noted better aligned with the claim language).

The Federal Circuit noted that it had “previously described RDOE as an ‘anachronistic exception, long mentioned but rarely applied.’” While the Court declined to definitively rule on the RDOE’s continued viability under the Patent Act of 1952, it favorably noted Steuben’s argument 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.” In this case, the Federal Circuit concluded that even if Shibuya had made a prima facie case under RDOE that the principle of operation of the accused product was so far removed from the asserted claim, “the jury’s verdict should not have been overturned under RDOE because [Steuben’s expert] provided rebuttal testimony that the jury was entitled to credit. JMOL of noninfringement was therefore improper.”

The district court had also analyzed whether, under the DOE, claimed structures, such as conveyor plates and systems, were equivalent to Shibuya’s rotary wheels and neck grippers. The district court concluded they were not. The district court had construed the term “means for filling the aseptically disinfected plurality of bottles [...]

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