The concept "design space" can be critical in the infringement analysis regarding a design patent, as codified in a judicial interpretation made by the PRC Supreme People's Court. A recent case handled and won by LexField demonstrates how the patent owner can proactively submit evidence showing a wide design space defying the general assumption for a subject product and thus winning a favorable judgment from the court.

Article 14 of the PRC Supreme People's Court's Interpretation (II) on Several Issues concerning the Application of Law in the Adjudication of Patent Infringement Dispute Cases prescribes that, where the design space is relatively small, the People's Court may hold that common consumers are generally more likely to notice minor differences between different designs. In practice, the alleged infringer would usually invoke this article to argue that his design does not infringe the asserted patent for noticeable minor differences in a small design space.

Normally, the party invoking Article 14 has the burden to prove the small design space. Nevertheless, as a strategic move, the patent owner may proactively introduce evidences proving a large design space, so as to preempt such a potential argument from the defendant and maintain a desirable momentum in the litigation. Such a strategy is particularly recommended if there may exist a false prima facie impression of a limited design space for the subject product. A recent case handled by LexField on behalf of a patent owner vividly demonstrates this point.

The case concerns a design patent on a zipper. The infringer raised the mere argument of a small design space but did not submit strong evidence. The infringer likely relied on the assumption that as zippers are commonly used in everyday life, people do not pay much attention to the shape of a single zipper tooth but presume that the shape of all zipper teeth are largely the same, which would imply a small design space for the shape of zipper teeth. In view of this, LexField proactively submitted a patentability assessment report of the asserted patent, which cites various prior zipper designs of very different tooth shapes. Citing this report as the authoritative evidence, the court explicitly held that the design space was large even for zipper teeth and then ruled in favor of the patent owner.