Analysis Of Limitations Of The Doctrine Of Equivalents In Patent Infringement

The doctrine of equivalents is an important principle developed by American courts in patent infringement cases and it has become a universal principle of patent law in almost every jurisdiction today. In recent years, the doctrine of equivalents is tested in a substantial proportion of patent infringement cases decided by courts or handled by competent administrative authorities in China. However, this doctrine is so flexible that it can be easily abused to prejudice the public interest. Thus there should be some limitations on its application. In China, the doctrine of equivalents is not yet adopted in legislation, and the only legal document incorporating this doctrine is the judicial interpretation promulgated by the supreme court in 2001, which is"Some provisions on the application of the law in the trial of patent cases". However, this judicial interpretation only sets some general principles concerning the doctrine of equivalents and does not impose any limitation for its application. Although this topic has great significance, little academic research has been devoted to this issue in China. It is the task of this thesis to examine the limitations on the doctrine of equivalents and to propose some legislative reform for China.There are three chapters in this thesis. Chapter one thesis introduces and analyzes the basic principles and specific provisions of the doctrine of equivalents. It then discusses the merits and shortcomings of the doctrine. Chapter two consists of three parts: the first part gives a brief introduction about the doctrine of estoppel and its development and explores the theoretical foundation and values of the doctrine of estoppel. By introducing and analyzing the case Festo v. SMC, the second part examinesthe latest development of the application of the doctrines of equivalents and the doctrine of estoppel by American courts in patent infringement cases. Most importantly, the third part puts forward to some legal suggestions on how to apply the doctrine of estoppel in China, and this is the focus of this thesis. Chapter three analyzes the highly controversial prior art defense doctrine arguing that the doctrine of prior art should be adopted to balance the doctrine of equivalents. Further, this chapter proposes some legal suggestions on the application of the prior art defense doctrine in Chinese patent law. This chapter lays its emphasis on theoretical foundation and the objects of this doctrine and its application.