Abstract:  In the context of economic globalization, the rapid development of patent internationalization is profoundly changing the pattern of the global patent system. Related researches on patent internationalization have been paid attention to in recent years. The existing researches mainly focus on the positive effects, negative effects, corporate behaviors and patent policies of patent internationalization. However, the related research on the quality of patent internationalization is still weak, and the quality of patent internationalization has not been evaluated quantitatively. Therefore, a patent internationalization quality index is constructed to evaluate the process of patent internationalization quantitatively in China.In order to evaluate the quality of patent internationalization quantitatively,this paper firstly reviews the evolution process of patent internationalization and analyzes the operation process. The patent internationalization quality index is constructed based on the Patent Cooperation Treaty (PCT) system. Secondly, the number of nations that PCT patent applications entered is selected as an important basis for the construction of the patent internationalization quality index. There are great differences in the number of patent applications between different countries and regions. In order to reflect the quality of patent internationalization, the number of nations that PCT patent applications entered needs to be revised in terms of the total number of international patent applications. Finally, the number of nations that the PCT patent application entered is extracted based on the status of international patent applications. The cumulative number of nations that PCT patent applications entered is accumulated one by one. The ratio of the cumulative number of nations that PCT patent applications entered to the annual total amount of international patent applications is calculated. The Patent Internationalization Quality Index (PIQI) is constructed on this account.The process of patent internationalization in China since 1994 is evaluated by the patent internationalization quality index constructed by the research. Based on the time series data of patent internationalization quality index, hierarchical clustering analysis is employed to analyze the characteristics and differences of different periods. The period characteristics of patent internationalization quality in China are revealed.The results show that the overall quality of patent internationalization is still low and much lower than the quality index of the United States, Japan and Germany at the same time. The evolution process of the patent internationalization in China can be classified into two periods. The patent internationalization quality index shows a fluctuating trend from 1994 to 2009. With continuous releasing of funding policies for patent internationalization and rapid increase of international patent applications, the patent internationalization quality index shows a declining trend since 2009. The patent internationalization quality index of China has declined in recent years. The reason is that most of the international patent applications did not enter the national phase. However, the applicants of these patent applications can still apply for funding under the current application funding policies. The policies prompt a large number of invalid patent applications that did not enter the national phase, which deviate from the policy goal of patent internationalization. Therefore, in order to encourage international patent applications to enter the national phase, it is necessary to adjust patent policies for application funding and shift the focus to the national phase.

Key words:  patent internationalization, quality index, patent policy, PCT system