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Patents: Introduction to Patent Searching

An introductory guide to patent searching.

What is a Patent?

Patents are government grants that give inventors exclusive rights to their inventions.

Patents are vital resources for businesses, researchers, inventors, academics, and others who need to keep abreast of developments in their fields.

Patents are also an important means of sharing know-how, because each patent document describes a new aspect of a technology in clear and specific terms and is available for anyone to consult.

Source: Canadian Intellectual Property Office

For the Beginning Searcher

Searching for patents on specific devices, processes, or inventions can be complex. If you are looking for a specific patent you can search by patent number or inventor’s name. However, if you are exploring what patents exist in certain areas you can search by keyword or browse the classification indexes:

European Classification System (ECLA)

U.S. Patent Classification System (USPC)

International Patent Classification (IPC)

Patent Offices of the World

European Patent Office (EPO)

Search Espacenet for European, U.S., and worldwide patents.


United States Patent and Trademark Organization (USPTO)

Search PATFT for issued patents and AppFT for patent applications

  • U.S. patents from 1790 to present, applications 2001 to present. Patents issued from 1790 through 1975 are searchable only by patent number, issue date, and current U.S. classifications
  • The older U.S. patents are presented as TIFF image files. (You can install a free TIFF reader that is designed in part for reading U.S. patent office files)
  • The USPTO classifies patents under the U.S. Patent Classification System (USPC)
  • Anatomy of a U.S. Patent Document


Canadian Intellectual Property Office (CIPO)

The Canadian Patents Database contains patent documents from 1869 to the present (full-text documents, 1920 to present.)

  • Note that the text of the abstracts and claims sections is not available for patents that were granted prior to August 15, 1978. These patents can only be searched by their patent number, titles, owner or inventor names, or classification.
  • Patent documents filed prior to October 1, 1989, are classified according to the Canadian Patent Classification (CPC) system. Patent documents filed on or after October 1, 1989, are classified according to the International Patent Classification (IPC) system.
  • Anatomy of a Canadian Patent Document


World Intellectural Property Office (PatentScope)

Search international patent applications (1978 to present) on Patentscope. The WIPO classifies patents according to the International Patent Classification (IPC) key.



Japan Patent Offices

Search the Patent Abstracts of Japan (PAJ) database




Links to Other Patent Offices around the World

Google Patent Search

This searches the USPTO.

Google Patent Search

Derwent Innovations Index

Derwent Innovations Index® facilitates rapid, precise patent searching, letting you conduct patent and citation searches of inventions in chemical, electrical, electronic, and mechanical engineering.

To search for patents, click on the link for Web of Knowledge below.  Then use the drop down menu to select Derwent.

Other Sources of Patent Information

Free Patents Online – free patent search website

The LensLENS.ORG – search and retrieve the full-text of over 130 million patent documents from over 95 countries. Advanced Boolean functions, structured search, biological search, classification search, filtering and sorting options.

Science Librarian Contacts

Please contact Li Zhang in the Science Library if you require further assistance.