Within the research process patent applications are often the first published account of the invention and it may also be the only published account. About 60 % of the information described in patents are not published elsewhere.
When searching in patent databases using notations of the International Patent Classification is a good tool to find subject specific patents which are often described in the title or the patent itself very global.

Patent DatabasesDEPATISnet – German patent information system

  • Free of charge, full texts in PDF
  • German patents from 1877
  • US patents from 1790
International Patent ClassificationCooperative Patent Classification via espacenet

  • Enhanced version of the IPC
  • Searching for the naming of classes and notations possible
US Patent and Trademark Office (USPTO)

  • Free of Charge, US patents
  • Full texts in tiff format, special viewer necessary!
Tables of the IPC in German via Depatisnet

  • displayed with all capillary ramifications
  • searching with English keywords for the naming of notations possible
Espacenet (European Patent Office)

  • Free of charge, full texts
  • German, European and world patents
English version of the IPC

Derwent Innovations Index from Clarivate Analytics

  • Important commercial patent database, not availbale within TUHH intranet
  • Patents world-wide

Older patents are often found only when searching for the exact patent number. Search in database fields like title, inventor, abstract, notation of IPC or even full text is often only possible starting from a distinct year which depends of database and country of origin of the patent.

More about patents