Chief Judge’s Dissent Questions Federal Circuit’s ‘Plainly Dissimilar’ Test for Design Patent Infringement

March 25, 2026

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A recent dissent by Chief Judge Moore of the Federal Circuit in Range of Motion Prods., LLC v. Armaid Co., Inc. takes aim at the Federal Circuit’s “plainly dissimilar” approach to analyzing design patent infringement, contending that the test incorrectly shifts the focus away from the overall similarity between the claimed and accused designs.

The appeal arose from a district court’s grant of summary judgment of noninfringement. The asserted design patent claims the design of a full-body massager with arms that adjustably clamp around a person’s limbs. The district court construed several aspects of the arms and overall design to be functional rather than ornamental. Then, after factoring out the functional aspects, the district court “thoroughly explained the differences that would stand out to an ordinary observer” and determined that these differences mean the accused and patented designs were “plainly dissimilar.” The patentee appealed, arguing that the accused and patented designs were similar enough that the infringement claim should have survived summary judgment.

The majority disagreed with the patentee. To reach that conclusion, the majority relied on the framework articulated in Egyptian Goddess, Inc. v. Swisa, Inc., 543 F.3d 665 (Fed. Cir. 2008) (en banc) and Ethicon Endo-Surgery, Inc. v. Covidien, Inc., 796 F.3d 1312 (Fed. Cir. 2015). Under that analysis, if “the claimed and accused designs are ‘sufficiently distinct’ and ‘plainly dissimilar,’ the patentee fails to meet its burden of proving infringement as a matter of law.” Ethicon, 796 F.3d at 1335 (quoting Egyptian Goddess, 543 F.3d at 678). The majority found no error in the district court’s use of the “plainly dissimilar” analysis and affirmed the district court’s summary judgment of noninfringement.

Chief Judge Moore dissented, stating that Egyptian Goddess—perhaps inadvertently—altered the substantial similarity test by shifting the frame of reference. Rather than asking whether two designs are substantially similar in overall appearance, the inquiry inverts the question and asks whether they are plainly dissimilar. Citing psychological literature and survey data, the Chief Judge explained that the framing of the infringement question can materially affect the outcome of the infringement analysis.

To illustrate the point, Chief Judge Moore invoked the familiar children’s puzzle that asks viewers to “find the differences” between two seemingly identical pictures, including the following image in her dissent.

When focusing on differences, she explains, one may lose sight of the overall similarity. Applied here, the Chief Judge reasoned that, had the focus been on similarities between the claimed design and the accused product rather than differences, a reasonable juror could find the designs substantially similar.

The dissent also raised concerns that the “plainly dissimilar” framing of the infringement test has led district courts to make factual determinations in place of the jury. While Chief Judge Moore acknowledged that a jury might ultimately conclude that the asserted design is not substantially similar in view of the prior art, she objected to taking the question away from the fact finder. Moreover, she expressed concern that continuing to rely on the “errant language” in Egyptian Goddess would “result in the near-complete removal of the jury from its fact-finding role in design patent infringement.”

Practice Tip:

While the majority’s decision confirms that courts may grant summary judgment of no infringement in design patent cases where the patented and accused designs are “plainly dissimilar,” Chief Judge Moore’s dissent could signal a willingness within the Federal Circuit to revisit that framework. Parties should consider that panels applying the dissent’s approach may disfavor summary judgment of noninfringement where dissimilarities exist and instead require reserving the question of “substantial similarity” for the jury.

Range of Motion Prods., LLC v. Armaid Co. Inc., No. 2023-2427, 2026 WL 261890 (Fed. Cir. Feb. 2, 2026)

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