IP Law Daily, PATENT—Fed. Cir.: Summary judgment of non-infringement affirmed in swimming pool design patent dispute, (Apr 25, 2025)

By Carolin Dennis, B.Sc., LL.B., LL.M.

District court correctly granted a swimming pool manufacturer’s motion for summary judgment of non-infringement as its pool was plainly dissimilar to North Star’s design patent.

The U.S. Court of Appeals for the Federal Circuit affirmed the district court’s grant of summary judgment of non-infringement in favor of Latham Pool Products, Inc., in a swimming pool design patent dispute brought by competing swimming pool manufacturer North Star Technology International Ltd. The appellate court concluded that no reversible error was found in the district court’s determinations (North Star Technology International Ltd. v. Latham Pool Products, Inc., No. 23-2138 (Fed. Cir. Apr. 24, 2025)).

Background. North Star Technology International Limited and North Star Technology Limited (collectively, North Star) owned and manufactured products that practice U.S. Design Patent No. D791,966 (the D’966 patent), which claimed the ornamental appearance of a swimming pool. Lathan Pool Products, Inc. (Latham) manufactured and sold a fiberglass swimming pool it branded as the Corinthian 16. Both the D’966 patent and the Corinthian 16 design relate to rectangular swimming pools with tanning ledges. In April 2019, North Star filed a complaint against Latham, alleging infringement of its D’966 patent. Latham filed a motion for summary judgment of non-infringement, arguing that the designs are plainly dissimilar and that any similarities that do exist between the D’966 patent and Corinthian 16 designs stem from their use of design elements that were commonly used in pool designs before the D’966 patent. The district court granted the summary judgment motion, agreeing that the prominent ornamental elements of the two designs including the shape of the entry steps and deep-end benches differ significantly, creating an overall ‘plainly dissimilar’ appearance. Further, it added that a review of the prior art confirmed non-infringement because each of the pertinent design elements included in the D’966 patent and Corinthian 16 existed before North Star filed the D’966 patent. Therefore, the district court entered judgment dismissing North Star’s claims. North Star timely appealed.

Infringement. The Federal Circuit noted that a design patent is infringed if, in the eye of an ordinary observer, giving such attention as a purchaser usually gives, two designs are substantially the same, and if the resemblance can deceive such an observer, inducing him to purchase one supposing it to be the other. The Federal Circuit agreed that the district court correctly identified that the D’966 patent’s ornamental features are characterized by straight edges and “geometric shapes,” producing an overall “angular appearance” while the Corinthian 16 is characterized by “rounded shapes” and a “curved” design. Both designs relate to rectangular swimming pools with steps, benches, and tanning ledges, but North Star’s patent only protects the ornamental aspect, the angular shape of those ubiquitous features.

The Federal Circuit found that because no ordinary observer, defined by the district court as a “homeowner considering purchasing a swimming pool for their home,” would accidentally purchase one pool thinking it was the other, the designs are plainly dissimilar. Although the designs share structural similarities, design patents only protect the original, “nonfunctional aspects of an ornamental design as shown in the patent.” A patented design that consists only of bringing together old elements with slight modifications of form is not infringed by another who uses the same elements with his own variations of form if his design is distinguishable by the ordinary observer from the patented design. Thus, North Star cannot monopolize common ornamental pool features or functional pool features by registering a combination of those features as a design patent.

The Federal Circuit also considered North Star’s arguments regarding the district court’s allegedly erroneous decisions to disregard or exclude certain evidence and found them unpersuasive. The Federal Circuit determined that the district court did not abuse its discretion in declining to consider documents that were not relevant or authenticated, or by striking lay testimony that lacked foundation and amounted to expert testimony from a witness who was not qualified as an expert. Accordingly, the Federal Circuit affirmed the district court’s grant of summary judgment on the issue of non-infringement.

The Case is No. 2023-2138.

Judge: Hughes, T.

Attorneys: Matthew James Dowd, (Dowd Scheffel PLLC) for North Star Technology International Ltd. and North Star Technology Ltd. Russell Korn, (Kilpatrick Townsend & Stockton, LLP) for Latham Pool Products, Inc.

Companies: North Star Technology International Ltd.; North Star Technology Ltd.; Latham Pool Products Inc.

Cases: Patent FedCirNews TennesseeNews