Patent Law Research Guide

• To determine whether your invention meets the requirements for patentability under 35 USC 101 - 103:  Novel, non-obvious, useful  (“Patentability Search”)*
• To determine areas of opportunity (State of the Art search)
• To determine whether a product infringes an existing patent (Infringment Search)
• To determine whether an existing patent is valid in light of already published prior art. (Validity Search).
• To do research on a company.

You will want to search by CLASSIFICATION in order to get more results than a keyword search, and for increased accuracy.  

Classification Systems:

• U.S. Patent Classification - "U.S."
• European Classification - "E.C.L.A."
• Cooperative Patent Classification - "C.P.C." = a merger of the above two
• International Patent Classification - "I.P.C." (Used by W.I.P.O.)

On January 1, 2013 the US PTO began using the Cooperative Patent Classification (CPC) system for published utility patent applications. In January 2015 the USPTO started using the CPC for granted utility patents as well as published applications.

Search Classification Systems 

Examine prior art, which is any publication in the public domain.   Prior art includes:

• Published patent applications  - U.S. and foreign
• Granted patents - U.S. and foreign
• Non-patent literature - journals, papers, web sites, manuals, patent landscape reports, etc. 

For details on what constitutes prior art, see Manual of Patent Examining Procedure, 900

You will also want to search by CROSS-REFERENCE to be thorough.  Once you find a relevant patent, see what patents and classification numbers are referred to by the patent.  

See Brown & Michaels How do I Read a Patent

Keep in mind that you can Shepardize or Keycite a patent to turn up cases, litigation documents and related patents.

(Format for shepardizing - shep: patno 6553350)

• Patents may be in the name of a Patent Holding Company, not the Corporation.  
• On the company's website, search for managers or employees with "technology" or "research" in their title, and search these names as an inventor.
• Run a trademark search for the company's product and find the owner (search as assignee).

1. Write out keywords to use to find classifications.
2. Search USPTO site to find patent classifications
3. Verify the relevance of patent classifications by viewing the definition, if that classification has a definition
4. Retrieve granted patents and applications with those classification numbers - https://ppubs.uspto.gov/pubwebapp/static/pages/landing.html.  Pick out the most relevant ones.
5. Review in depth the patents you selected above.  Pay close attention to the additional drawings pages, the specification and especially the claims. References cited by the applicant and/or patent examiner may lead you to additional relevant patents.  Look at Current U.S. Class and Current International Class to see if any more classes apply.
6. Broaden your search to find additional U.S. patent publications besides using keyword searching in Patent Public Search, classification searching of non-U.S. patents on the European Patent Office's Worldwide Espacenet patent database (https://worldwide.espacenet.com(link is external)) and searching non-patent literature disclosures of inventions using the free electronic and print resources of your nearest Patent and Trademark Resource Center (https://www.uspto.gov/ptrc).

Because of the change to the Patent Public Search from the prior PatFT and AppFT, the original seven steps are now condensed to 6 steps.  But the USPTO site still refers to this as the Seven Step Strategy. See the USPTO's Seven Step Strategy

Thomas Edison. Photo courtesy of Wikipedia