Wonderland Switzerland AG v. Evenflo Company, Inc.

Wonderland Switzerland AG v. Evenflo Company, Inc., decided December 17th, 2025. A divided panel of the Federal Circuit, in an opinion by Chief Judge Moore, reversed in part a judgment in a child car-seat patent case. The court held that the doctrine of equivalents applies element by element, reversed one infringement finding, reversed the permanent injunction, and remanded for a new trial on willfulness. Judge Reyna concurred in part and dissented in part. Here's the brief.

Wonderland owns two patents directed to car seats for children — U.S. Patent No. 7,625,043 and U.S. Patent No. 8,141,951. It sued Evenflo in the District of Delaware, accusing five convertible car-seat models, grouped as the "4-in-1 seats" and the "3-in-1 seats," of infringing claims of both patents.

A jury found infringement across the accused products. It found that the 3-in-1 and 4-in-1 seats infringed the '043 patent under the doctrine of equivalents, and that the accused seats infringed the '951 patent both literally and under the doctrine. The jury found the '043 infringement was not willful.

After trial, the district court entered a permanent injunction covering both patents — even though Wonderland had moved to enjoin only the '043 patent — and denied Wonderland's motion for a new trial on willfulness. Evenflo appealed the judgment and the injunction. Wonderland cross-appealed the denial of a new trial.

Three questions framed the appeal.

First, whether substantial evidence supported the finding that the 4-in-1 seats infringed the '043 patent under the doctrine of equivalents. Under that doctrine, a product that does not literally meet a claim may still infringe if the differences are insubstantial — but the comparison is made limitation by limitation.

Second, whether the district court abused its discretion in granting a permanent injunction, which requires the patent owner to satisfy the four traditional equitable factors, including irreparable harm that money cannot repair.

Third, whether the court abused its discretion in denying a new trial on willfulness after excluding certain evidence of Evenflo's intent.

On the doctrine of equivalents, the court reversed the finding that the 4-in-1 seats infringed the '043 patent. Claim 1 requires the seat back to include a locking mechanism for selectively detachably connecting it to the seat assembly. In the accused 4-in-1 seats, the seat back held only a stationary metal bar; the parts that selectively attach and detach sat on the seat assembly. Wonderland's expert argued the overall mechanism was the same, but the court explained the doctrine cannot be used that way.

Because the components for selective detachability were on a different element, the court held no reasonable jury could find equivalence.

The court affirmed the remaining infringement findings, including those on the '951 patent.

Turning to remedy, the court reversed the permanent injunction as to both patents. The '951 injunction was improper because Wonderland had declined to seek it. As for the '043 patent, the eBay factors were not met.

Finally, the court reversed the denial of a new trial on willfulness. It held that the district court should not have excluded, under Rule 403, an email chain in which Evenflo was asked how to avoid the claims of the patent. Judge Reyna dissented from that part, concurring in the rest. He would have affirmed, reasoning that the majority substituted its own judgment for the district court's careful Rule 403 balancing under a deferential standard of review.

Wonderland restates that the doctrine of equivalents operates element by element. Equivalence is measured against each claim limitation, not the accused device as a whole, so placing a claimed feature on a different component cannot supply equivalence for the element that lacks it. The decision also confirms that a permanent injunction demands non-speculative proof of irreparable harm under the eBay framework, and that an injunction cannot stand for relief a patent owner never requested.

Wonderland Switzerland AG v. Evenflo Company, Inc., No. 2023-2043, decided December 17th, 2025. I'm Kyle Coleman. Thanks for watching.