Worldwide nanotechnology development: A comparative study of USPTO, EPO, and JPO patents (1976-2004)

Xin Li, Yiling Lin, Hsinchun Chen, Mihail C. Roco

Research output: Contribution to journalReview articlepeer-review

76 Scopus citations


To assess worldwide development of nanotechnology, this paper compares the numbers and contents of nanotechnology patents in the United States Patent and Trademark Office (USPTO), European Patent Office (EPO), and Japan Patent Office (JPO). It uses the patent databases as indicators of nanotechnology trends via bibliographic analysis, content map analysis, and citation network analysis on nanotechnology patents per country, institution, and technology field. The numbers of nanotechnology patents published in USPTO and EPO have continued to increase quasi-exponentially since 1980, while those published in JPO stabilized after 1993. Institutions and individuals located in the same region as a repository's patent office have a higher contribution to the nanotechnology patent publication in that repository ("home advantage" effect). The USPTO and EPO databases had similar high-productivity contributing countries and technology fields with large number of patents, but quite different high-impact countries and technology fields after the average number of received cites. Bibliographic analysis on USPTO and EPO patents shows that researchers in the United States and Japan published larger numbers of patents than other countries, and that their patents were more frequently cited by other patents. Nanotechnology patents covered physics research topics in all three repositories. In addition, USPTO showed the broadest representation in coverage in biomedical and electronics areas. The analysis of citations by technology field indicates that USPTO had a clear pattern of knowledge diffusion from highly cited fields to less cited fields, while EPO showed knowledge exchange mainly occurred among highly cited fields.

Original languageEnglish (US)
Pages (from-to)977-1002
Number of pages26
JournalJournal of Nanoparticle Research
Issue number6
StatePublished - Dec 2007


  • Information visualization
  • Nanoscale science and engineering
  • Nanotechnology
  • Patent analysis
  • Patent citations
  • Research and development (R&D)
  • Self-organizing maps
  • Technological innovation

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • Atomic and Molecular Physics, and Optics
  • Modeling and Simulation
  • General Materials Science
  • Condensed Matter Physics


Dive into the research topics of 'Worldwide nanotechnology development: A comparative study of USPTO, EPO, and JPO patents (1976-2004)'. Together they form a unique fingerprint.

Cite this