Sub Assembly Mapping Strategies under PRC Patent Law
Mapping sub-assemblies against PRC patent claims separates component scope from combined assembly limitations to manage indirect liability and customs hold risks.
Doctrine of Equivalents
Meaning
Judicial standards in patent litigation allow courts to find infringement even when a product does not literally copy every claim of a patent. This principle, known as the doctrine of equivalents, applies if the accused product uses features that perform substantially the same function, in the same way, to achieve the same result as the patented technology. It prevents competitors from making minor alterations to escape liability, which secures the investment made by patentees in the domestic market.
Equitable Adjustment
Judges use this method to protect the economic value of inventions from evasive modifications. Under the doctrine of equivalents, the court evaluates if the differences between the features are insubstantial to a person having ordinary skill in the art. This standard prevents bad-faith copying.
Legal Application
Chinese courts apply the rule during civil trials with strict limitations to avoid unfair expansion of patent rights. The doctrine of equivalents cannot be used to recapture subject matter that was surrendered during patent prosecution. Prosecution history estoppel acts as a boundary.
Manufacturing Precaution
Foreign manufacturers operating in China must conduct freedom-to-operate searches that analyze equivalent features rather than just literal claims. Neglecting the doctrine of equivalents exposes a factory to sudden injunctions and asset freezes by local tribunals. This risk is managed through careful design clearance before mass production.