On The Application Of Doctrine Of Equivalents

Although one or some technical elements of infringing products or methods are different from technical elements of claims of the patent, yet they have no non-substantive difference, that's called the doctrine of equivalents (here in after"DOE"). DOE as regulator is a variety of interests of the value of the game of choice. The application of DOE enlarges explication of the claims properly to further expand the protection of the interests of the patentees; at the same time, the restrictions of the applications of DOE protect the interests of the public to a certain extent, encouraging others to apply existing technology to bold innovations, increasing social wealth. DOE occupies a very important position in the judgments of patent infringement, which balances the interests of patentees and the public.The value of DOE is embodied in two main objectives, the value of justice and the value of benefits, which are in good use and expressed in the process of applying DOE and the restrictions of it. And it's just these values that exactly decide the crucial position of DOE in the judgments of patent infringement.The compromise model of claims supplies reasonable limits for deciding the scope of patent protection, as the application of DOE is moderate expansion of these reasonable limits. Therefore it is necessary to establish a uniform standard for the application of DOE, from the main, object, time and other aspects. It must be noted that there are some special circumstances, such as changing of the inferior technology, roundabout innovation, which should be regarded as direct equivalent and should be alleged infringed.As has been taken forward, the appearance of DOE protects interests of patentees much more. In order to balance the interests of patentees and the public, it is necessary to apply restrictions to the principle. In particular, Doctrine of Prosecution History Estoppels and Prior Art Defense are taken as the restrictions.DOE is very important but China's Patent Law doesn't expressly prescribe DOE, which principle is only referred to in relevant judicial interpretations and appears in some standardized documents that guiding the court internal trial. This phenomenon leads to problems of poor legal effect and low operation. However, in judicial practice, in essence DOE has already been accepted and actually applied by judges. There are some of the more exciting cases in China.