Written by: Bryant Chen & Nathan D. Reeves

STEUBEN FOODS, INC. v. SHIBUYA HOPPMANN CORPORATION

Before Moore, Hughes, and Cunningham. Appeal from the United States District Court for the District of Delaware.

Summary: Conflicting expert testimony constituted substantial evidence supporting the jury’s rejection of a reverse doctrine of equivalents argument.

Plaintiff Steuben sued Defendant Shibuya for infringing three patents. After a jury found the patents valid and infringed, the defendant moved for JMOL of noninfringement. For one of the patents, the defendant argued that its product did not infringe under the reverse doctrine of equivalents (RDOE), which holds that a product does not infringe if its principle of operation is sufficiently different from that of the asserted claim. The district court granted the motion, finding that the defendant’s expert provided testimony supporting the RDOE argument and that the plaintiff’s contrary expert testimony was wrong as a matter of law. The plaintiff appealed.

The Federal Circuit reversed, holding that the district court erred in relying on RDOE to overturn the jury’s verdict of infringement. As an initial matter, the court declined to decide whether the RDOE, a common law doctrine, survived the 1952 Patent Act. The court acknowledged that it has never affirmed a noninfringement finding based on the RDOE, and it once again refused to decide whether the doctrine is viable. Instead, the court ruled that the plaintiff’s expert testimony constituted substantial evidence supporting the jury’s rejection of the defendant’s RDOE argument. The court stated that, because the jury heard conflicting expert testimony regarding the principle of operation, a factual issue, it is presumed to have resolved the conflict in favor of the verdict. Accordingly, the Federal Circuit reversed and reinstated the jury’s verdict of infringement.

Editor: Sean Murray