Patents Overview
Patents provide important technical literature. There are approximately 10 million patents in the U.S. The US Patent and Trademark Office (USPTO) is the official site and answers many questions concerning the patent process. A patent for an invention grants a property right to the inventor, usually for 20 years. The USPTO isn't the best place for patent searching, though, instead search Google Patents or Patent Lens, and the sites listed further below. Both patent applications and granted patents are included.
This image shows the major parts of a patent. Purdue University points to several good tutorials on patent search strategies, including a discussion of patent classification systems. See also this guide's tab on patent classifications.
The Best Patent Web Sites
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Google Patents
Fastest place to go for all U.S. patents, U.S. patent applications, and European patents.
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ESPACENETEsp@cenet is especially good for classification searching. Contains European patents, World patents, and patent applications. Ability to search patents by origin country (i.e. CN for China). Downloadable and printable in PDF. Ability to download bulk data.
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Patent Lens (the Lens)Integrated visualization tools plus the ability to download bulk data.
Cornell Patent Office
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Center for Technology LicensingCalled CTL, this is Cornell's main office on campus for patent management.
Questions?
More Patent Databases
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Canadian Patents DatabaseCanadian Intellectual Patent Office (CIPO) contains all Canadian patents and images from 1933 to the present.
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FreePatentsOnlineRequires registration to access PDFs of patents. Allows for RSS feeds and PDF and XML data downloads.
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Japan Patent Office (JPO)Access to japanese patent abstracts.
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SciFinderIndexing chemical information from over 100 years of journals, books, patents, conference proceedings, technical reports, dissertations and reference works. Search by chemical structure, name or keyword. First time users need to register at http://resolver.library.cornell.edu/misc/6197957.
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United States Patent and Trademark OfficeAccess to all U.S. patents and U.S. patent applications. Can examine patent class definitions. and use search box on this page for keyword searching of class definitions. Search interface is still clumsy, recommend other databases on this page for non-classification searching.
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World Intellectual Property Organization PatentScopeWIPO PATENTSCOPE contains 73 million world patents and 3.5 million patent applications, including national/regional collections. Includes an AI-based translation tool.
Patent Searching Prior to 1976
Prior to 1976 patents searching is a bit complicated. While full-text should be available in Google Patents, some has been scanned with OCR - optical character recognition - and there are numerous spelling errors. The print indexes below may be helpful in these cases:
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Annual Report of the Commisioner of PatentsLibrary Annex has print volumes from 1842-1965. These have good indexes to patentees and inventions, and are needed due to poor quality of OCR records.
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Official Gazette of the US Patent and Trademark OfficeThis microfilm set may be necessary to consult as the online version is not easy to use, esp. for older patents. 1872-1975. Abstracts with one drawing only.
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Index of Patents from the United States Patent OfficeLibrary annex volumes cover 1920-1973
Engineering Librarian

Engineering Library
Cornell University
Ithaca, NY 14853
jhp1@cornell.edu
engrref@cornell.edu