The US Court of Appeals for the Federal Circuit issued a mixed ruling in a dispute over patents covering child car seat technology, explaining that infringement under the doctrine of equivalents requires an equivalent for each and every claim element, and that a grant of injunctive relief requires proof of all eBay factors. On the issue of willfulness, the panel majority held that the exclusion of exculpatory evidence was a reversable error. Wonderland Switzerland AG v. Evenflo Co., Inc., Case Nos. 23-2043; -2233; -2326 (Fed. Cir. Dec. 17, 2025) (Moore, Prost, JJ.) (Reyna, J., concurring in part and dissenting in part).
Wonderland owns two patents directed to convertible child car seats. Wonderland alleged that Evenflo’s four-in-one convertible seat models infringed its patents. A jury found infringement of one patent under the doctrine of equivalents and infringement of the other patent both literally and under the doctrine of equivalents. The district court entered judgment and permanently enjoined Evenflo from activities related to both patents. Evenflo appealed.
Evenflo challenged the finding of infringement under the doctrine of equivalents for the first patent, arguing that its accused seats lacked the claimed “locking mechanism for selectively detachably connecting” the seat back to the seat assembly. The Federal Circuit agreed, finding that no reasonable jury could find equivalence because the claim “plainly requires the seat back to include the components for selective detachability,” whereas Evenflo’s seats “simply include a stationary metal bar” and all locking components reside on the seat assembly. As a result, the Court concluded “there c[ould] be no equivalence as a matter of law.”
Evenflo also argued that the district court abused its discretion in permanently enjoining activities relating to both patents. Regarding the first patent, the Federal Circuit found that the district court abused its discretion in granting a permanent injunction because Wonderland expressly declined to request such relief. Wonderland argued the grant of a permanent injunction as to the first patent was harmless error because it had the same “practical effects” as the injunction for the second patent. The Court disagreed, explaining that the injunction could affect Evenflo’s release of other products, which may not necessarily infringe the second patent.
Regarding the second patent, the Federal Circuit concluded that the district court abused its discretion in granting a permanent injunction because it relied solely on speculative and conclusory evidence that Wonderland suffered, and would continue to suffer, irreparable harm or injury that could not be compensated with monetary damages. The Court explained that the district court failed to identify evidence that Wonderland’s partner lost sales or market share to Evenflo rather than other competitors, or that the partner’s reputation or product distinctiveness was harmed. The Court also noted that testimony that a lost car seat sale “naturally leads” to loss of other product sales was based on conjecture without supporting data. Finally, the Court found that statements that consumers “might think” technology problems existed if Evenflo’s product failed were deemed speculative and insufficient to establish irreparable harm.
Wonderland cross-appealed, asserting that the district court abused its discretion by denying a new trial on willful infringement after excluding evidence of Evenflo’s subjective intent. The excluded evidence included an email chain from an affiliated company warning that an accused product might fall within the scope of the patent and asking how to “avoid the claims.” The Federal Circuit agreed, finding the emails “highly relevant” to willfulness because they showed awareness of infringement risk. The Court noted that any prejudice could have been mitigated through limiting instructions or redaction.
Ultimately, the Federal Circuit reversed the judgment of infringement under the doctrine of equivalents for the first patent, vacated the permanent injunction as to both patents, and reversed the denial of a new trial and remanded for further proceedings on willful infringement.
Judge Reyna dissented in part, arguing that the district court’s exclusion of the email evidence regarding the willfulness assertion under Federal Rule of Evidence 403 was “careful and comprehensive” and should have been upheld under the deferential standard of review.
Practice note: This decision underscores the Federal Circuit’s strict approach to equivalence analysis and its willingness to revisit evidentiary rulings on willfulness where probative value is high.
