Case Studies Based On The Application And Limitation Of The Equivalent Infringement

With the rapid development of science and technology,patent infringement is mainly reflected as to infringement under the Doctrine of Equivalents(abbreviated as DOE).DOE means there is non-substantive difference between the one or more technical features of the accused infringing products or methods with the characterization which have been written in patent claims,even though the difference really does exist.The application of DOE expands the scope of patent protection.At the same time,restrictions on it also balance the benefit between the patent holders and the public to some extent.Because the patent claims record the zone of protection,how to judge whether the case meets patent infringement:the first step is to explain the claims and determine the protective range,The second step is doing comparative analysis about technical characteristics between the accused infringing products or methods with the interpretated requirements so as to draw a conclusion if it is the equivalent infringement act.This paper is mainly divided into four parts.Chapter One is a theoretical base, introducing the development history of DOE and public objection on it.On the second chapter,writer chooses three typical cases about equivalent infringement and describes each one from three aspects,Firstly introduce the basic facts,Secondly analysis of the cases, the end summarize the cases.The main problems on application of the DOE in China can be reflected.Then the main content of Chapter Three is to analyze the focus,the writer think there are two problems in these cases: one is scope verification of patent protection,the other is the identification of equivalent characteristics.The forth part expounds the limitation on the applying of the DOE.Although prosecution history estoppel and principle of existing art plea have imposed proper restrictions on application of DOE,the identified conditions of equivalent should also be strictly limited.In the final conclusion,the writer believes that we must enlarge the scope of patent protection.Patent applicant should write in these foreseeable equivalents and contents required to be protected in specification into the claims,in order to further expand the scope.