On The Doctrine Of Equivalents In Patent Infringement Litigation

The doctrine of equivalents is one of the most important judicial principles in patent infringement litigation. This paper systematically studies the applying and limitations of the doctrine of equivalents and also discusses the jurisprudence basis and the value of it. By researching legislations and litigations of the doctrine of equivalents in China, this paper puts forward proposals to perfect patent system related to the doctrine of equivalents. This paper is composed of five parts.The first part is the meaning and the history of the doctrine of equivalents. The doctrine of equivalents presents its main ideas as follows: The first, the precondition of applying the doctrine of equivalents is no literal infringement; The second, one element or several elements of the claims of the patent is duplicated by the accused infringement; the third, the allegedly infringing device performs substantially the same function in substantially the same way to obtain substantially the same result as the patent and this substantial equivalent is obvious to the common technical personnel in the same realm. The doctrine of equivalents has been established and developed gradually in the United States by the legal precedent. The First legal precedent of agreeing the doctrine of equivalents by the American Supreme Court is Winans v. Denmead in 1853. The aim of the doctrine of equivalents is to avoid cheating in patent.The second part is the specific application of the doctrine of equivalents. The original intention of the doctrine of equivalents is to avoid that the accused infringers escape patent right infringement legal liability through some slight non-substantive changes. However, the accused infringer's subjective intention should not be taken as the preconditions of applying of the doctrine of equivalents, that is, subjective fault should be taken as circumstances instead of elements of the infringement liability under the doctrine of equivalents.There are two kinds of theories for object of the doctrine of equivalents. One is called the overall-effect analysis which holds that the court should take the accused infringement as a whole to compare with the patent claims when applying the doctrine of equivalents. The other is all-element test which holds that the court must find each technical characteristic or its equivalent of the patent claims in the accused infringement in a determination of patent infringement. The overall-effect analysis once played a positive role in the early patent system. But under the conditions of modern technology development, the overall-effect analysis has been increasingly inappropriate to the occasion. Compared with the overall-effect analysis, all-element test suited to the modern patent system better. Giving the condition that not to expand the claims, the best way is to apply the doctrine of equivalents in each element of the claims.Another important issue is tests to determine the equivalents. The function-way-result identity test which was advocated by The Supreme Court of US is the most acceptable and was widely used. There's another test called"insubstantial differences"test advocated by the United States Federal Circuit Court of Appeals. In addition, there's a test called"Obviousness"test advocated by the Germany. These tests provide effective methods and paths to determine the equivalents,while determination of equivalents should be done case by case, for the aim of the doctrine of equivalents is to realize fair.The third part is outer limitations to the doctrine of equivalents. Prosecution history estoppel in patent system means that if the patent holder gave up something in patented claim process, he will not be allowed to"pick up"these things later to against the alleged infringers during the patent infringement lawsuit. Revised claim and argument for the distinction between the application technology and the existing technology would lead to an estoppel. While the case dismissed for insufficiently clear description of the invention wouldn't lead to an estoppel. Limitation to the doctrine of equivalents by prosecution history estoppel presents two kinds of situation, that is,"complete bar"and"flexible bar". Under"complete bar", the doctrine of equivalents was completely blocked up by prosecution history estoppel, which sounds unreasonable to some extent.The argument of prior art means that the alleged infringers refute the accusation by arguing that the technology he used is the prior art or close to the prior art. When creative degree of the patent is not high enough, that is, the scope between the patent technology and the prior art is not wide enough, there must be an overlap region between the doctrine of equivalents application scope and the prior art application scope. Technologies in this overlap region either could be regard as the patent technology according to the doctrine of equivalents or the prior art according to the argument of prior art. Then to apply the doctrine of equivalents or the argument of prior art came into a choice. Under such circumstances the argument of prior art should be given priority reasonably."Donation rules"means that the art recorded in the patent specification but not included in the patent claim should be regard as donating to the public and never be allowed to apply the doctrine of equivalents."Foreseeable rules"means that the art which the patent holder should have foreseen and write into the claim during patent application should never be allowed to apply the doctrine of equivalents. As a new limit to the doctrine of equivalents,"donation rules"presents much practical significance. While,"foreseeable rules"sounds too rigid to the patent holder.The fourth part is the jurisprudence basis and the value analysis of the doctrine of equivalents. For the purpose of public interest, the patent system is an institutional arrangement to coordinate and balance the public and the private interest by means of protecting the private interests of the patentee. According to the unique mechanism of the patent law, there is a basic community of interests between the public and the patentee, but under a dialectical inspection there is a conflict between the two sides. Conflicts and contradictions of interest between the patentee and the public need to be adjusted appropriately by patent law so as to achieve balance. As a part of the patent system, the doctrine of equivalents is not to serve the patentee only, but must pay attention to the interest balance of the public and the patentee. In this sense, the doctrine of equivalents is a regulator to balance the interests of the patentee and the public.Introduction of the doctrine of equivalents to patent infringement is because of the special features of the patent system, that is,the patent claim system. On the one hand, it is the requirement for clear and accurate interpretation of the scope of patent protection for the claims. On the other hand, it is impossible to meet this requirement. Applying the doctrine of equivalents could remedy the defect which the claim system exposed. That is just the value of the doctrine of equivalent. However, to apply the doctrine of equivalent too broadly will squeeze the space of the development of new technologies for the public, destroy the system of claim and bring too many uncertainties to patent infringement litigation. Therefore, we must make proper restrictions to the doctrine of equivalent in order to keep balance of interest between the patentee and the public.The fifth part is improving of China's patent system relevant to the doctrine of equivalents.At present, legislation of the patent system related to the doctrine of equivalents is almost in a state of blank in China. Only the 56th article of Patent Law of PRC and the 17th article of Several Provisions of the Supreme People's Court on Issues Concerning Applicable Laws to the Trial of Patent Controversies is far less than the needs of judicial practice of patent infringement litigation. The main difficulties and obstacles in applying the doctrine of equivalents are lacking of unified nationwide standards and unified court system, also are the complexity and professionalism of the doctrine of equivalents. To establish a unified standard is the key to scientific applying the doctrine of equivalents in China .When applying the doctrine of equivalents in patent infringement litigation in China, we should take"equitable"as the guiding concept. According to the need of the patent practice in China, we should impose relatively stringent restrictions on the scope of the doctrine of equivalents. When applying the doctrine of equivalents in China, we should pay attention to the peculiarities of utility model patents and should establish a system of substantial examination before utility model patents litigation.