North Star Technology International LTD. v. Latham Pool Products, Inc., decided April 24, 2025

Case Name and Citation: North Star Technology International LTD. v. Latham Pool Products, Inc., No. 2023-2138 (Fed. Cir. April 24, 2025) (nonprecedential)

Court: United States Court of Appeals for the Federal Circuit

Lower Court: United States District Court for the Eastern District of Tennessee (No. 3:19-cv-00120-KAC-DCP, Judge Katherine A. Crytzer)

Date of Decision: April 24, 2025

Issue: Did the District Court err in granting summary judgment of non-infringement in favor of Latham Pool Products, Inc., finding that Latham's "Corinthian 16" swimming pool design was plainly dissimilar to North Star Technology International Ltd.'s U.S. Design Patent No. D791,966?

Holding: No. The Federal Circuit affirmed the District Court's grant of summary judgment, finding no reversible error in its determination that the accused design was plainly dissimilar to the patented design.

Main Themes and Important Ideas/Facts

Design Patent Infringement Standard: The court reiterates the established "ordinary observer" test for design patent infringement, quoting Egyptian Goddess, Inc. v. Swisa, Inc.: "[i]f, in the eye of an ordinary observer, giving such attention as a purchaser usually gives, two designs are substantially the same, if the resemblance [can] deceive such an observer, inducing him to purchase one supposing it to be the other." The court emphasizes that when the claimed and accused designs are "plainly dissimilar," the patent owner fails to meet its burden of proving infringement.

Focus on Overall Appearance: The court stresses that the comparison of designs must be based on the "claimed design as a whole, and not in the context of separate elements in isolation," citing Ethicon Endo-Surgery, Inc. v. Covidien, Inc.

Dissimilarities in Ornamental Features: The District Court, and affirmed by the Federal Circuit, found significant differences in the "prominent ornamental elements" of the two designs, leading to an overall "plainly dissimilar" appearance. Specifically:

North Star's D'966 patent features "straight edges" and "geometric shapes"—producing an "angular" appearance.

Latham's Corinthian 16 is characterized by "rounded shapes" and a "curved" design.

A key example cited is the entry steps: "the entry step in the D’966 patent is a pool-width rectangle, while the Corinthian 16 has two separate curved entry steps shaped like quarters of a circle."

Role of Prior Art and Common Design Elements: Latham argued that any similarities between the designs stemmed from "design elements that were commonly used in pool designs before the D’966 Patent." The District Court agreed, noting that "[e]ach of the pertinent design elements included in the D’966 Patent and Corinthian 16 . . . existed before [North Star] filed the D’966 Patent." Examples included pre-existing rectangular tanning ledges and Latham's prior use of the same deep end benches.

Distinction Between Ornamental and Functional Features: The court emphasizes that design patents protect only the "original, 'nonfunctional aspects of an ornamental design as shown in the patent.'" quoting Elmer v. ICC Fabricating, Inc. It clarifies that North Star cannot use its design patent to "monopolize common ornamental pool features or functional pool features by registering a combination of those features." Citing Lee v. Dayton-Hudson Corp., the court states that "[d]esign patents do not and cannot include claims to the structural or functional aspects of the article' and are limited to the 'ornamental design' of the article." The court further quotes Egyptian Goddess stating that a design patent consisting "only of bringing together old elements with slight modifications of form" is not infringed by a distinguishable design using the same elements.

Ordinary Observer: The District Court defined the ordinary observer in this case as a "homeowner considering purchasing a swimming pool for their home." The Federal Circuit found no error in this definition.

Evidentiary Rulings Affirmed: The Federal Circuit upheld the District Court's decisions to disregard irrelevant or unauthenticated documents and to strike lay testimony that lacked foundation or constituted unqualified expert testimony. The court found no "abuse of discretion" in these rulings.

Key Quotes

"If, in the eye of an ordinary observer, giving such attention as a purchaser usually gives, two designs are substantially the same, if the resemblance [can] deceive such an observer, inducing him to purchase one supposing it to be the other." (Egyptian Goddess, Inc. v. Swisa, Inc.)

"Where the claimed and accused designs are 'plainly dissimilar,' the patent owner does not meet its burden of proving infringement." (Egyptian Goddess, 543 F.3d at 678)

"Differences . . . must be evaluated in the context of the claimed design as a whole, and not in the context of separate elements in isolation." (Ethicon Endo-Surgery, Inc. v. Covidien, Inc.)

"[T]he '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.'" (quoting the District Court)

"[E]ach of the pertinent design elements included in the D’966 Patent and Corinthian 16 . . . existed before [North Star] filed the D’966 Patent." (quoting the District Court)

"[D]esign patents only protect the original, 'nonfunctional aspects of an ornamental design as shown in the patent.'" (Elmer v. ICC Fabricating, Inc.)

"[D]esign patents do not and cannot include claims to the structural or functional aspects of the article' and are limited to the 'ornamental design' of the article." (Lee v. Dayton-Hudson Corp.)

"[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.'" (Egyptian Goddess, quoting Zidell v. Dexter)

Significance: This nonprecedential decision reinforces the importance of considering the overall ornamental appearance of designs in infringement analysis. It also highlights that design patents do not grant exclusive rights to common or functional design elements, even when combined in a particular way. The case underscores that summary judgment of non-infringement is appropriate when the differences between the patented and accused designs are so significant that no ordinary observer would likely be deceived.

Full opinion