The Study of the Knowledge Spillover pattern in China through patents in USPTO

Abstract

本文通過研究美國專利局的中國專利，主要探討了以下兩個問題：1、哪些性質會影響專利的傳播；2、引證專利與被引證專利間有哪些關係。在數據方面，本文主要使用了2000 年至2012 年美國專利局發明人為中國的專利。通過分析其中G 類（物理類）和H 類（電學類）類專利是否有被其他專利引證，本文發現，專利權人、發明人所在地以及科技領域都會對專利是否會被引證造成影響，相比其他兩個因素，科技領域的影響不能被忽視。在專利權人方面，企業專利被引證的概率較高，政府和研究機構的專利被引證的概率較低，在企業方面，台灣、美國和其他國家的企業都較易被引證。在地理位置上，京津冀和長三角的專利都比珠三角的專利更易被引證，而中國境內其他地區的專利都更不易被引證在科技領域，G08 類（信號裝置類）、H01 類（基本電子元件）和H05 類(其他電氣技術)專利被引證的概率最高，H03（基本電子電路）類專利被引證概率最低。此外，一項專利引證其他專利的數量與和專利的年齡都與專利被引證的概率有正向關係。在引證專利和被引證專利的关系上本文發現，專利更傾向於引證與自己專利權人類型相同，地理區域接近，科技領域相似的專利This thesis studies the pattern of knowledge spillover in China based on patent citation. The data used are patents granted by USPTO to inventors based in China with the application year dated between 2000 and 2012. Only patents falling under the categories of G and H of the International Patent Classification, where the Chinese patents are concentrated, are investigated. The theme of study is: How patent citation is affected by the status of the patent owner (assignee), the location of the inventor, and the technology scope of the patent. The empirical results show that all three factors matter, but they are inter-related and their effects may overlap. In general, patents assigned to business firms are more likely to be cited compared to patents assigned to government and academic institutions, especially patents belong to non-Chinese companies, including those based in U.S., Taiwan, and other countries.Among different technological fields, patents in the categories of G08, H01, H05 are most likely to receive citations, while G01 and H03 are least likely. Patents invented in Greater Beijing area and Yangtze River Delta are more likely to be cited than patents invented in Pearl River Delta. Moreover, the probability to receive a citation is positively related to the number of citations of the original patent and the age of the patent. A patent is more likely to be cited by another patent owned by the same kind of assignees (business, academics, or institutions), invented in the same location, or falling in the same technology category, than otherwise