North Star Files Petition for Rehearing Challenging CAFC’s ‘Sufficiently Distinct’ Test for Design Patent Infringement

Last week, fiberglass pool design company North Star Technology filed a combined petition for panel rehearing and rehearing en banc at the U.S. Court of Appeals for the Federal Circuit to challenge that court’s decision this April affirming the Eastern District of Tennessee’s grant of summary judgment of noninfringement in a design patent case against Latham Pool Products. North Star’s petition argues that the appellate panel employed a “sufficiently distinct” test for infringement that lacks objective guardrails, inappropriate for the summary judgment posture of the appeal and similar to other areas of design patent law recently realigned with the utility patent context by the Federal Circuit.

This April, a Federal Circuit panel including Circuit Judges Alan Lourie, Raymond Chen and Todd Hughes found no reversible error in the Eastern Tennessee district court’s determination that the Corinthian 16 pool manufactured by Latham is plainly dissimilar to the ornamental design for a swimming pool claimed by North Star’s U.S. Design Patent No. D791966. Citing the ordinary observer standard for design patent infringement outlined by the Federal Circuit in Egyptian Goddess v. Swisa (2008), the Federal Circuit found that the curved design of Latham’s accused pool was plainly dissimilar from the angular shape of the ubiquitous pool features claimed in North Star’s design patent.

North Star: Design Patent Scope Not Expansive, But Exists and Cannot Be Ignored

The plainly dissimilar test, which North Star’s petition characterizes as the “sufficiently distinct” test, is not only overly subjective but also violates the ordinary observer test laid down by the U.S. Supreme Court in Gorham Co. v. White (1871), which looks at whether the resemblance between designs, when considered as a whole, would deceive such an observer into purchasing an infringing product supposing it to be the patented article. In Gorham, the Supreme Court found infringement despite clear ornamental differences in the accused spoons after determining that the effect of the whole design was substantially the same despite minor differences.

“Design-patent scope may not be expansive, but it exists and cannot be ignored,” North Star’s petition reads. The “substantially the same” infringement standard for design patents incorporates an equivalency analysis, typically performed by juries in the utility patent context, and Latham’s arguments at trial that design patents have almost no scope cannot be reconciled with cases following Gorham holding that minor or trivial differences will not evade infringement. The lack of an analytical framework for the sufficiently distinct test nearly two decades following its introduction should lead the Federal Circuit to discard the test or reserve it for frivolous design patent claims that clearly look nothing alike.

The lack of objective standards for the sufficiently distinct test further does not comport with the summary judgment standard under Federal Rule of Civil Procedure 56, North Star argues. “If the ‘sufficiently distinct’ test is intended to impose a special gloss on Rule 56, that gloss cannot stand,” North Star’s petition reads, adding that no patent-specific exceptions exist to the Rule 56 standard such that the fundamental question of infringement can be resolved by the court in the face of competing evidence.

Proper Three-Way Comparison With Prior Art Frame of Reference Shows Infringement

The sufficiently distinct test should not be used to dispose of reasonably close design patent infringement cases at the summary judgment stage, North Star argues, as the test forces courts to speculate what reasonable jurors would decide without the benefit of an objective prior art context. Symptomatic of the sufficiently distinct test, the Federal Circuit decided new issues of patent scope and functionality for the first time on appeal. Worse, North Star contends that the panel decision did not acknowledge evidence that the symmetry of the patented design did not exist in the prior art pools sold by Latham before it began marketing the Corinthian 16 design.

On summary judgment, several inferences should have resolved in North Star’s favor, the petition argues, but the appellate panel’s opinion didn’t acknowledge circumstantial evidence of replacement purchases or direct evidence of similarity, including an Instagram post by an experienced pool distributor misidentifying North Star’s patented design for Latham’s Corinthian 16 pool. Under a three-way comparison that considers prior art pool designs as a proper frame of reference, authorized under Egyptian Goddess’ design patent infringement standard, North Star argues that a reasonable jury could have found infringement in light of the Instagram evidence and witness testimony establishing that consumers do not focus on corner steps and other features that the Federal Circuit panel highlighted in its plainly dissimilar finding.

While the Supreme Court has not addressed design patent issues in the nearly 20 years since Egyptian Goddess was decided, the Federal Circuit has recently been realigning standards for deciding design patent issues with those used for utility patent cases. In last year’s LKQ Corp. v. GM Global Technology Operations, the Federal Circuit overruled the Rosen–Durling test for design patent obviousness, finding that the two-step framework requiring courts to first identify a prior art reference basically the same as the claimed design was overly rigid in light of the Supreme Court’s landmark KSR ruling mandating a flexible approach to obviousness in the utility patent context.

Image Source: Deposit Photos
Author: 72soul
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This article was updated on 6-30-25 at 11:58AM to clarify that North Star is arguing “a reasonable jury” could have found infringement in light of the Instagram evidence…”, not that the Federal Circuit should have.