AMICUS PARTICIPATION SOUGHT IN NORTH STAR V. LATHAM. ISSUES: THE UNDEFINED “SUFFICIENTLY DISTINCT/PLAINLY DISSIMILAR” TEST FOR DESIGN PATENT INFRINGEMENT, AND A SIGNIFICANT SUMMARY JUDGMENT QUESTION

The Federal Circuit unexpectedly handed down a quick decision in North Star v. Latham on April 24, 2025, a mere 2+ weeks after oral argument (link here to audio). The Court’s opinion was, to be kind, confusing. The Court affirmed the district court’s order granting Latham’s motion for summary judgment of non-infringement based on the district court concluding that the patented and accused designs were “sufficiently distinct”. This finding was reached despite the court having no guidelines for such a determination.

Full disclosure: I am lead counsel for North Star.

I refer you to my recent blog post for a short summary of the oral argument, as well as links to the parties’ appeal briefs.

North Star has decided to file a Petition for Rehearing and Rehearing en banc. As noted previously, this case raises a terribly significant issue for design patent owners. More particularly, the issue involves the standard for determining design patent infringement, particularly on summary judgment. North Star is seeking amicus support which can be critical to whether the Petition is granted.

The case involves the design of a pre-fabricated swimming pool, and provides an opportunity to clarify the application of the “sufficiently distinct” test (a/k/a “plainly dissimilar”). This test was mentioned in passing in one sentence in Egyptian Goddess yet never defined by any court and still incredibly critical in determining design patent infringement. Significantly, the Court’s opinion in Egyptian, before even mentioning “sufficiently distinct”, spent several pages stressing the need to determine infringement “in the context of the prior art”.

Equally important in the Court’s decision, it upheld the lower court’s decision at the summary judgment stage—despite infringement (“substantially the same”) being a fact question and despite evidence of retailer confusion in a social media post. The outcome is in no way consistent with Gorham v. White, Egyptian Goddess, and Anderson v. Liberty Lobby.

North Star’s patented pool design and Latham’s accused infringing design appear below:

The two pools both had the combination of six specific design features in common:

(1) a large rectangular tanning ledge extending across the full width of the pool;

(2) two linear rectangular steps leading from the tanning ledge to the shallow end of the pool, both linear steps extending the full width of the pool;

(3) long, thin substantially rectangular benches in opposite corners of the deep end of the pool;

(4) the same general proportions of the tanning ledges, linear steps, and rectangular benches;

(5) a bottom wall that has a gradual slope beginning at the two linear rectangular steps and continuing to the opposite deep end; and

(6) longitudinal symmetry with respect to the above elements (1) – (5). In other words, both pool designs have the same appearance from both sides.

If these six elements were in a utility patent claim, it would be literally infringed by Latham.

A visual comparison of the designs shows the high degree of similarity. The similarity of the patented design and the accused infringing design is further highlighted by the three-way test—an objective comparison of the two designs at issue with the closest prior art design, an analysis endorsed by the Court in Egyptian. This three-way test was not challenged by Latham. Following is one example used in North Star’s brief:

It is fairly clear that - even to an ordinary observer - the overall appearance of the patented and accused designs are much closer to each other than either is to the overall appearance of the prior art pool.

The Federal Circuit ignored North Star’s three-way tests, and declined to explain how a court or factfinder is to assess whether an accused design is “sufficiently distinct” or “plainly dissimilar” from the patented design.

Instead, the panel appeared to discount North Star’s patented design because it contains design elements that are not novel. Slip op. at 5 (“North Star cannot monopolize common ornamental pool features or functional pool features by registering a combination of those features as a design patent.”). Of course, North Star’s patent does not “monopolize common ornamental pool features,” as there are myriad configurations of pools—just as there are myriad configurations of tables even though all tables have a set of legs and a flat surface. Instead, the patented pool design captures an ordered combination of elements arranged in a unique way to create a popular pool product.

The panel’s opinion adds further confusion to the undefined “sufficiently distinct” test because the opinion conflates ambiguous arguments about patentability and functionality—even though the district court’s grant of summary judgment did not rely on functionality or validity.

Judge Hughes’s remarks during oral argument—which conflicted sharply with his written opinion— illustrate why, at a minimum, this case should have gone to the jury:

“But if I'm a homeowner looking at these two designs, they look pretty similar to me. They're rectangles. They have tanning beds. They have steps. They have benches on the deep end. They look fairly similar with very minor differences between the two things. I mean, do you think that if it had gone to a jury and they found infringement that we would be looking to reverse this on a JMOL? I mean, it seems to me like just the two pictures would be substantial evidence to support infringement.”

The Petition is currently due May 24, 2025. North Star has filed a request for a one-month extension (to which Latham has agreed) which if granted would push the deadline to June 23, 2025. Amicus briefs supporting North Star (or neither party) are due two weeks after the petition is filed.

North Star seeks amicus support, from IP associations, corporations, and clients of design patent practitioners. Amicus support is critical at the petition stage, as evidenced by the recent LKQ case. If you, your company, your association, or any of your design-forward clients are interested in becoming an amicus, or if you have any questions, feel free to email me at ps@perrysaidman.com and I will send you a memo that discusses these issues in greater detail.

By the way, my paper “Sufficiently Distinct” – “An Insufficient Test for Design Patent Infringement” has now been published in IP Theory, a journal of Indiana University’s Maurer School of Law, and is available there for download.