Abstract
Prior art retrieval plays an important role in patent examination. If a patent examiner can retrieve prior art for an application patent quickly and accurately, he or she will be able to efficiently and effectively judge the novelty of an application patent, and in turn, avoid hampering the technology development of the application domain. Moreover, in order to avoid losing tangible and intangible assets caused by patent infringement, companies need to search patent prior art before doing development. However, the increasing number of patents is not seen only in quantity but also in complexity. Bewaring the emerging need of prior art retrieval form large patent database, the main objective of this project is to develop a methodology which can build the claim hierarchy automatically in order to facilitate the identification of relevant patent prior art. Most existing patent retrieval tools use keywords to find relevant patents; however, they ignore the structure of the invention, which mentions in the claim of patent. Thus, this study parses the sentences of patent claim and finds the structure of the invention. Then, we compare the similarity of structure of invention and find the relevant patent. We first convert the claim sentence into the claim hierarchy to represent the structure of invention, and use specification of patent to expand the words in claim hierarchy. Finally, we calculate the similarity of invention structure and use the threshold to find the relevant patents. This claim hierarchy based search will reduce the cognitive load of prior art judgment by comparing similar invention structure between patents.