Application Of Doctrine Of Equivalents In The Functional Claims

Pursuant to the relevant rules in Patent Law of the People’s Republic of China, the scope of patent right shall be confined by description in patent claims, the content of patent claims and drawings within could be used for interpreting claims. Generally, the interpretation standard for traditional claims shall be clear and definitive. However, since the fast development of information technology, the claims in relevant area frequently adopt certain portion of functional claims. Functional claim itself has certain special features, on defining the scope of patent by interpreting relevant claims, the rules in the Guidelines for Examination and Judicial Interpretation made by the Supreme People‘s Court adopt ―double standard‖. Different interpretation would certainly cause divergence in regulatory and judicial system, and then affect the stability and predictability of patent system. Before the introduction of unified standard, it is necessary to discuss the current problem. Taking the existence of functional claims as premise, combining the literal meaning of doctrine of equivalents and claims, the scope of patent shall cover all application means which are able to fulfill the claimed functions. Apparently, such interpretation may also cover application means which are able to fulfill the claimed functions but have essentially different nature. No matter which interpretation standard will be adopted, functional claims would always afford applicant wider patent scope than traditional structure feature. Since by no means encouraged by patent law, the equivalents in functional claims should be treated differently to traditional equivalents: for equivalents, the time of identification should be the time of infringement; for functional claims, the time should be the time of application of claims. In these two situations, notwithstanding the technical contribution of published contents are same but protection to them are different, it does not contradict to the principle of Publicity in Exchange of Protection. It is not unjustifiable to adopt a relevantly adverse time on identifying the equivalents in functional claims. Therefore, by interpreting claims and comparing technical methods in tort procedure, a relatively reasonable balance of interest could be reached – no bias towards or against patent holder, and no constraint on public space of liberal innovation.