• Journal of Legislation Research
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• no.41
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• pp.201-228
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• 2011

In 97hu2200, the Supreme Court of Korea suggested five requirements to apply the doctrine of equivalents, i.e. identity of problem-solving principles, interchangeability, ease of interchangeability, exception of known arts and file-wrapper estoppel. There have been arguments on whether the standard of ease of interchangeability could be regarded as the same as the obviousness standard in deciding patentability. The side who thinks that they are different (hereinafter, the side of difference) considers that the standard of ease of interchangeability is narrower than the obviousness standard. This side criticizes the side who thinks that they are the same each other (hereinafter, the side of the same) on the reason that doctrine of equivalents can be overly expanded. On the other hand, 'the side of the same' argues that every accused invention having no inventive step from the perspective of the patented invention should be considered to infringe. 'The side of the same' points that if the standard of ease of interchangeability is considered as narrower than the obviousness standard, 'grey area' should exist where the patent law cannot work. The difference between the two side may cause contradictory results in the decision of infringement under the doctrine of equivalents. Because 'the side of difference' construes claims narrowly than 'the side of the same,' an accused invention in the grey area is not regarded to infringe. 'The side of the same,' however, considers the accused invention to fall into the scope of the patent under the doctrine of equivalents. This paper concludes that the standard of ease of interchangeability should be regarded as the same as the obviousness standard from the perspective of economics of innovation.