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On the Principle of Equivalence in American Patent Law

Release time:

2016-12-09 11:36

When dealing with patent infringement disputes, the most controversial and strongest issue for a long time is the principle of equivalence. "The equivalence theory originated in the United States and is used to adjust the boundary between the increasingly diversified inventions and the degree of interpretation of patent specifications. It is usually used as the theoretical basis for strengthening patent rights." Equivalent infringement is relative to literal infringement, and its meaning refers to: the product or method accused of infringement is compared with the claim of a patent, although one or several elements of the accused infringing product or method are different from the limits or elements in the claims, there is only an insubstantial difference between the two; or if one or several elements of the accused infringing product or method are equivalent to one or several limits or elements in the claims, the accused infringing product or method constitutes equivalent infringement of the patent ".

In determining the doctrine of equivalence, the United States Supreme Court's decision in 1950, Graver Tank V Linder Air Products Co., was the most important judgment of the doctrine of equivalence. "Through this case, the judge held that limiting patent rights to literal infringement would only encourage competitors to find insignificant substitutes for the claimed invention. Therefore, the patent office's authorization would only prevent inventors from seeking effective patent protection, thus contrary to the purpose of the patent system" The essence of the doctrine of equivalence is to prevent the alleged infringing object from circumventing infringement by changing the minor details of the claimed invention while maintaining substantially the same function, infringement may occur.

The non-material distinction criterion is the starting point for determining equivalent infringement, but reaching this criterion does not necessarily lead to the conclusion of infringement "there are four important factors that limit the application of the principle of equivalence" they are all technical characteristics of the existing technical guidelines. Review Process Estoppel Guidelines and Public Contribution Guidelines "These guidelines are frequently questioned in patent infringement litigation".

The doctrine of equivalence is a matter of fact, derived by fact testers. The essence of the doctrine of equivalence is that the alleged infringing product or process contains the same or equal technical features in the claims.

Source:http://www.iprlawyers.com/ipr_Html/08_04/2006-3/6/20060306144816550.html