The Doctrine of Equivalents: Protection Beyond Literal Language

The protection conferred by a patent is defined through claims, which determine the scope of protection of the claimed subject matter, whether it is a product or a process. It is within said scope that patent owners can exercise their exclusive right to prevent third parties from using their invention without their consent.

In alleged patent infringement cases, what must be analyzed is whether the alleged infringing object (i.e. a product or process) meets all the features that are literally claimed in the patent, either exactly or by including all the claimed features alongside additional ones provided that the claims are open-ended (i.e. when terms such as “comprising” are included). However, a strictly literal interpretation of the claims could be insufficient and detrimental to the protection of patent owners’ rights, since a third party could avoid a potential patent infringement by making minor modifications in relation to the protected invention. In other words, a purely literal interpretation of the claims could render a patent vulnerable to potential avoidance strategies seeking to circumvent its literal scope of protection.

To address this issue, the Doctrine of Equivalents is applied, which is a legal rule that allows to extend the scope of protection of a patent beyond the scope that can be obtained from the literal wording of its claims, and that is recognized in many of the patent systems of the different countries or territories in the world. Through this doctrine, patent owners have an additional tool to argue that their patent is being infringed, even when the object used by a third party differs from the literally claimed subject matter, provided that such differences are minor and/or insubstantial, and the object can be deemed equivalent.

It is important to point out that, although the general concept of the Doctrine of Equivalents is shared by many jurisdictions, each territory applies specific criteria, mainly developed through its case law, to determine whether an alleged infringing object is equivalent to the invention protected by the patent and whether there is infringement under said doctrine. This means that two patents of the same family, protecting the same invention with an identical scope of protection, could lead to different outcomes against the same object accused of infringement having differences in relation to the protected invention. Therefore, while in one territory the accused object could be deemed equivalent and constitute a patent infringement by equivalence, in another territory it could not be deemed as such and consequently fall outside the scope of protection.

In addition, even though the different territories may have application criteria of the Doctrine of Equivalents that lead to opposite results, there are good practices and fundamental principles that must be considered when drafting a patent application and during its prosecution before a Patent Office. These practices and principles aim to maximize not only the scope of protection obtained from a literal interpretation of the claims of a potential patent, but also the possibility that, in the event of a patent infringement dispute, such patent can rely on the Doctrine of Equivalents to include equivalent objects within its scope of protection.

In conclusion, the Doctrine of Equivalents reinforces the ability of patent owners to effectively protect their invention, allowing the scope of protection of their patents to comprise objects that, although not literally encompassed, can be deemed equivalent to the claimed invention.