특허분쟁으로 무효화된 특허의 특징 ―우리나라의 무효심판 자료에 대한 실증분석

We study factors affecting the validity/invalidity judgement of a patent involved in invalidation litigation, using the data set of 6,367 patents involved in invalidation trials from 2001 to 2017. We estimate the multinomial logit model by separating invalidity into invalidity by legal/administrative judgement and invalidity by the patent holder’s decision. We find structural heterogeneity between two types of invalidity judgements in factors affecting validity/invalidity status. Most importantly, we find that factors related to the novelty and the defensive power in the lawsuit affect positively the probability of invalidity by legal/administrative judgement whereas factors related to the patent’s strategic stake affect negatively the probability of invalidity by the patent holder’s decision. Our study indicates that patent’s economic value and patent’s strategic stake are key aspects in determining the validity/invalidity judgement of a patent when it is involved in the invalidation litigation, and that the strategic stake is an important aspect for the patent holder to decide on participation in (or continuation of) legal dispute. The role played by the strategic stake is especially conspicuous in the analysis of patents whose patentees are firms.