本研究以美國核准太陽能光伏相關技術為研究對象，其專利公告年介於1976年1月13日與2014年3月11日之間，並利用Freeman (1979)所提出五個網絡中心性作為衡量專利在引證網絡中的重要程度指標，以Tobit Model作為研究模型，探討影響專利在引證網絡中重要程度的因素為何。首先，探討那些專利特性為影響專利在引證網絡當中重要程度的關鍵因素；接著我們將樣本限縮至申請人為公司，並加入廠商特性變數作探討；最後為申請專利範圍和專利技術覆蓋範圍對於專利引證網絡之非線性關係探討。 實證結果共有五個特別的發現，第一，專利核准後至第一次被引證的時間差距是最重要的影響因素，專利核准後至第一次被引證的時間差距越短，越能夠增加專利所獲得的直接以及間接向前引證，甚至能夠提高專利在網絡中握有多數資訊的重要地位；第二，若專利權人能夠持續支付專利維護費以維持專利的有效性，則會增加專利所獲得的直接以及間接向前引證，當專利到達第三次繳交維護費期限時維護專利有效性對於專利所獲得的直接以及間接向前引證之影響更為明顯；第三，擁有越多的申請專利範圍越能夠影響專利所獲得的直接向前引證，其影響幅度隨著申請專利範圍的增加而遞減；第四，專利使用的非專利文獻引證越多會增加專利的直接以及間接向後引證；最後，專利技術覆蓋範圍同時影響專利的向後引證以及向前引證，專利技術覆蓋範圍越廣越能增加專利的間接向後引證以及其所獲得直接向前引證，對於直接向前引證的影響隨著專利技術覆蓋範圍的增加而遞減。 ;The purpose of this article is to investigate the determinants of patent citation network. The analysis is based on patents of photovoltaic granted by the US Patent and Trademark Office (USPTO) from 1976/01/13 to 2014/03/11. The way we weigh the patent in the citation network is “Centrality” proposed by Freeman (1979). In order to find what critical elements affect the position of patent in the citation network most, we use tobit model to analysis. In the beginning, we put patent characteristics variables in our model. Then, we add firm characteristics variables. In the end, we try to figure out if the number of claims or the scope has concave relation toward centrality. There are five interesting findings. First, the most important determinant is the time lag between granted year and first cited year. If a patent that is immediately cited by other patent, it will have more direct and indirect forward citations. And the citation lag can also affect the position of a patent in the citation network. Second, if assignee keeps paying the renewal fee, it will raise the frequency of direct and indirect forward citations especially when it is due to the last term. Third, the number of claims has a positive effect toward direct forward citations. The degree of influence decreases as the number of claims increases. Fourth, the use of non-patent knowledge positively affects direct and indirect backward citations. Final, the broader the scope a patent has, the higher the frequency of backward citations and forward citations it can receive. The degree of influence toward indirect forward citation decreases as the scope increases.
