Design patent infringement turns on the ordinary observer test: whether the accused design and claimed design appear substantially the same to an ordinary observer familiar with the relevant prior art. The analysis concerns the claimed visual design, not simply whether two products perform the same function or share several components. [1]
Identify what the patent claims
A design patent protects an ornamental design embodied in or applied to an article of manufacture. The USPTO distinguishes the article’s visual appearance from a utility patent’s protection of how an invention works. The drawings and claim therefore define the starting point, including which portions are claimed rather than merely shown as context. [2]
For example, comparing two commercial products without consulting the issued patent can miss a crucial distinction. One product may include visual features that the patent never claimed, while a commercially unimportant-looking detail may be part of the protected design.
Compare overall visual impressions
In Egyptian Goddess v.Swisa, the Federal Circuit rejected a separate “point of novelty” infringement test and adopted the ordinary observer approach as the sole test. A claimant does not prove infringement merely by isolating one supposedly novel feature that appears in the accused product. The claimed design must be considered through the governing overall comparison. [1]
Differences are not ignored, but the analysis is not a mechanical checklist in which a majority of matching features wins. Perspective, proportions, configuration, and the combined appearance can matter.
Use prior art to understand the comparison
The court explained that plainly dissimilar designs may resolve the issue without more. In closer cases, prior designs can help show what differences would matter to an informed ordinary observer. Where the field contains many similar designs, a difference that looks minor in isolation may carry greater significance. [1]
Prepare a useful evaluation
- Obtain the complete issued patent and relevant prosecution record.
- Identify claimed and unclaimed visual portions.
- Compare consistent views of the accused design.
- Gather relevant earlier designs.
- Separate infringement from validity and remedy questions.
A patent’s validity can be disputed under separate standards; ordinary-observer similarity does not decide novelty or obviousness. For related topics, see design patent damages and defenses and patent priority under Section 120. An earlier filing date and a visually similar product answer different parts of a patent dispute.
Primary sources
Sources checked: October 31, 2026.