On The Doctrine Of Equivalents In Patent Infringement

The doctrine of equivalents is an important judicial principle which was put forward by American Court in the practice of Patent Infringement. It has a history of nearly 200 years and it has grown into a rather perfect theory system. The doctrine of equivalents has being accepted world-widely under the influence of America. Facing the absence of detailed legal interpretations for the doctrine of equivalents, therefore, it is of great theoretical and practical value to explore the applicable situation, applying methods and limitations by researching the basic theory and related cases of the western countries as well as the judicial practice in China.This paper includes three parts: preface, main text and conclusion.The preface mainly analyses the reality and necessity of the doctrine of equivalents and the cause that regard it as research object.This main text is composed of three parts; each presents its main ideas as follows:The first part: The doctrine of equivalents background introduces the basic theory of the doctrine of equivalents, and studies its historical process in America.The second part: The application of the doctrine of equivalents researches how judicial practice use the doctrine of equivalents, and it is divided into two sections. Section one: Premise of applying the doctrine of equivalents demonstrates that the doctrine of equivalents should apply the principle of strict liability attribution. Section two: The application of the doctrine of equivalents includes five steps: 1.Determining the time of equivalence infringement so as to decide the time of as that of equivalence infringement; 2.Determining the scope of protection of patent right; interpreting the terms of the claims with eclectic principle. 3. Determining the quantity of technical features; 4.Determining the applicable principles of the patent infringement doctrines; 5.judging the infringement of equivalents by Function-Way-Result Test. The third part: Limitations to the doctrine of equivalents discusses the principles used in restricting the doctrine of equivalents, Prosecution history estoppel and Prior art counterplead doctrine.Finally, the paper presents some improvement proposal about how to exert the doctrine of equivalents in China connecting with the present legislation and justice condition of China. The proposal mainly concerns making some principles and method concrete and characteristic to establish a perfect Equivalent Infringement Theory skeleton.