Research On The Application And Restriction Of The Doctrine Of Equivalents

With long time developments of Patent System, a protection mechanism that focuses on patent claim has been formed. The patent claim, on the one hand, is a definition of invention-creations; on the other hand, it plays a role in showing the scope of protection to the public. For the purpose of the aforesaid, the claim construction herein has contributed greatly. Further, the equivalent construction under the doctrine of equivalent is an essential link to the process of the claim construction. Together with the literally construction, they constitute a complete procedure of the claim construction.The doctrine of equivalent (DOE) had been developed along with the course that the claim construction has becoming mature in the judicial practice. DOE was established in America about two hundred years ago. In China, DOE is approved both by academics and practical circles. Moreover, there are some discussions on the limitation of DOE, for instance the Prosecution History Estoppel and the Prior Art Defense. However in judicial practice, they do not appear to have reached a consensus on some detail issues. This article makes every effort to analyze the necessity, application and limitation of DOE from two aspects of theory and judicial practice, and raise writer's own discretion thereof.There mainly has four parts of this article: Part one is preface. This part gives a brief introduction of the development of DOE and raises some disagreements in the academics and put forward the meaning and destination of aiming at DOE as the research object.Part two is the summary of DOE. It introduces the significations of DOE at first, and then emphasis on the necessity of DOE. This part of article gives an analysis on the inseparable relations between DOE and claim construction. Also illustrate the necessity of DOE by presenting the development of it in America.Part three is application of DOE. This part is divided into six sections, in which it combines with cases to provide a more detail discussion on how to apply DOE in judicial practice. It specifically discusses the following aspects: the pre-conditions of claims construction, to refer to the internal proof in the process of claims construction, the people who shall determine the equivalent infringement, the time points that be used to determine the equivalent infringement and the comparison between the two creativities. During the concrete process of analysis, the writer Compares different views in this regard, and put forward some proper manners and standers on my own opinion.Part four is limitation of DOE. This part gives a careful discussion about the two Principles of Prosecution History Estoppel and the Prior Art Defense that can effectively limit the use of DOE. In the same way, the writer takes a strategy of comparing both sides'opinions, and then makes relevant suggestion on my own descriptions.