基于专利相似度的突破性技术发明识别研究——以纳米技术为例

Identification of breakthrough inventions based on patent-to-patent similarity: A case study of nanotechnology

随着我国发明专利申请数量的迅猛增加,如何通过事前和事后指标测度并识别技术和经济价值高的突破性技术发明就成为学术界面临的焦点问题。本文利用专利的国际专利分类(IPC)信息构建两两专利相似度指标,并引入时间维度对过去、当前以及未来三个时间段的专利相似度比较,测度专利的新颖性、独特性和影响力,从而构建突破性技术发明的综合识别方案。然后,以纳米技术为例,利用美国专利商标局(USPTO)在1989—2010年的6618条授权发明专利数据进行实证检验。结果表明:(1)利用IPC分类相似度识别突破性技术发明具有可行性,基于专利IPC四位和六位分类的相似度指标分别可以识别出6.23%和5.06%的纳米技术专利为突破性技术发明;(2)基于专利相似度识别的突破性技术发明与基于专利被引数识别的突破性技术发明具有显著的正相关关系。但是,两类识别方法得到的结果中仅有不足总样本的0.5%是相同的,表明以往单纯依赖专利被引数据识别突破性技术发明可能存在一定偏差;(3)对突破性技术发明来源特征的实证检验表明,基于专利相似度和基于专利被引数的突破性技术发明在发明人和组织来源特征方面基本一致,而在发明层面的知识来源特征方面则不一致,进一步反映出两类识别方案的差异性。本研究弥补了已有识别方案过于依赖专利引文信息的不足,既为企业在实践中挖掘和利用高价值发明专利提供参考,也对未来突破性技术发明相关研究达成一致结论具有重要意义。

With the rapid increase in the number of patent applications in China,how to measure and identify breakthrough inventions with high technology and economic value has become a hot issue.Since 2011,the number of invention patent applications in China has ranked first in the world for eight consecutive years.However,how to identify breakthrough inventions through ex ante and ex post indicators remains a problem in academia.Thus,it is of significance to identify the invention patents with major breakthroughs and turn them into productivity in China.Considering the general lack of citation information in Chinese patents,this paper draws on the definitions and identification criteria of breakthrough inventions by Dahlin and Behrens(2005)to construct the patent-to-patent similarity index with the IPC information of patents.Considering both the ex ante and ex post indicators of patents,we introduces the time dimension to measure the novelty,uniqueness,and impact of patents by comparing the similarity of patents in the past,current and future periods,so proposing a comprehensive identification solution for breakthrough inventions.In order to test the validity of our identification solution,we choose the field of nanotechnology as an example.As one of the fastest growing and widely influential emerging science and technology fields in the world,nanotechnology is a typical interdisciplinary technology field.The cross-domain attributes of nanotechnology determine the wide range of IPC classifications involved,which is suitable for our research using patent IPC classification and is more useful to reveal the invention characteristics of technologies in the emerging interdisciplinary domains.Then,we conduct an empirical test by using the granted invention patents in nanotechnology from the United States Patent and Trademark Office(USPTO)in 1989-2010.Our conclusions are as follows.First,we find that it is feasible and operational to use IPC classification similarity to identify breakthrough inventions.Specifically,we can identify 6.23%and 5.06%of nanotechnology patents as breakthrough inventions with the similarity indicators based on IPC four-and six-digit classifications.Second,by comparing with the breakthrough inventions identified based on patent citation,this paper verifies the validation and difference of the breakthrough inventions identified based on patent IPC classification similarity.This paper finds that there is a significant positive correlation between breakthrough inventions identified based on patent similarity and based on patent forward citations.At the same time,however,this paper finds that only 0.5%of the results obtained by the two types of identification methods are the same,indicating that it may be biased by purely relying on patented citation data to identify breakthrough inventions in the past,so the identification solution based on IPC classification similarity is a useful supplement.Finally,through the comparative study of the source characteristics at the invention-,inventor-and organizational-level,this paper further validates the effectiveness and difference of the breakthrough inventions identified based on patent IPC classification similarity.The breakthrough inventions based on patent similarity and patent citation shows basically consistent results in inventor and organizational characteristics,indicating the validation of the new identification solution based on patent IPC similarity in the inventor-and organizational-level.At the same time,however,this paper also finds that the two types of identification methods show inconsistent results in the characteristics of the invention′s knowledge source,indicating that the previous research results on the source characteristics of the invention may be affected by the breakthrough invention identification method.Thus,we suggest that future research on the source of breakthrough inventions needs to pay attention to different identification methods.