Application of Doctrine of Equivalents in Patent Infringement Disputes

Due to the emergence of fast moving technology, there are more disputes than ever, requiring the courts to carefully interpret the patent claims. In a vacuum, claim terms are of little use. They must be interpreted and given meaning so that they can be used in a given context. Various patent doctrines have been recognized as tools for creating specific patent scopes, as a result, implementing specific patent theories. This paper evaluates and deals with scope and extent of patent claims, whenever claim infringement takes place with respect to the doctrine of equivalents (DOE). The possible mechanisms and tests as developed by the Judiciary are also discussed. The paper also examines certain limitations/bars on the applicability of the doctrine of equivalents. An attempt has been made to understand the applicability of doctrine of equivalents as highlighted by courts of various jurisdictions especially US, European and Japanese courts. The Indian context, which is largely based on UK laws, is also reviewed with reference to the latest cases in this regard. Finally, after identifying various mechanisms developed by various courts, it is concluded that as there is no settled position of law till date, it is the ripe time for the Indian courts to formulate basic parameters and principles pertaining to doctrine of equivalents in patent claim infringement disputes.