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Research Guides


While the Library reference service staff is happy to provide assistance with your patent or trademark research, we cannot perform searches, evaluate searches, assist with your application or dispense legal advice.

The University of Washington and its employees are providing a service of an informational nature with no express or implied warranty for results and assume no obligation or liability for damage arising out of the use, or inability to use, the information provided.  Every effort is made to keep this information up to date. However, errors and omissions may occur.

For the most up-to-date information or legal advice, please contact a patent or trademark attorney.


What is a patent and what is patentable?
A patent gives its owner the right to exclude others from making, using, and selling the patented invention. To be patentable an invention must meet three criteria.

  • Useful. Virtually any usefulness will suffice, provided that it is functional and not aesthetic.
  • Novel. It must differ physically in some way from all prior art. The physical hardware must be different, there must be a new combination of hardware, or there must be new use.
  • Nonobvious. The differences between your invention and prior art must not be obvious to one with ordinary skill in the field.

Patent searching is a time consuming enterprise.
You cannot simply see if something has been patented. You have to make sure the item has not been patented. Hence, it is a process of elimination. This means that you must examine each patent in your subject area to determine if there is prior claim to your ideas.

You must search as far back in time as your invention has been technologically possible.
Anything that has previously been patented cannot be re-patented, even though that patent may have expired. Once a patent expires, the invention becomes part of the public domain, meaning that anyone may be able to use or manufacture the invention listed within.

Patent searching is a step by step process.  Here is a general overview of the steps:

  • First, brainstorm terms that describe your invention.  Write a list of words and phrases that describe your invention.
  • Second, establish relevant classes and subclasses (class-subclass schemes) by using the Cooperative Patent Classification system.
  • Third, review definitions for relevant CPC Classifications.
  • Fourth, search for issued patents using CPC Classifications.  Review patent titles and front pages.
  • Fifth, in-depth reading of relevant patents selected from title and front page review.
  • Sixth, search, retrieve and review published patent applications using CPC Classifications.
  • Seventh, broaden your search using keywords, the old U.S. Patent Classification (USPC), and other tools, depending upon your available time and interests.

There are no shortcuts to doing a complete patent search.
Although there is a keyword searching feature in the USPTO database, keyword searching is generally not the most thorough way to conduct a patent search. There is no controlled terminology or vocabulary; patentees can use a wide variety of words to express their ideas. This is the reason a classification system is in use. It groups all of the patents in a specific subject area together for the purposes of examination.

Just because you have not seen a product on the market does not mean that there is not a patent on that item. Obtaining a patent and marketing an invention are two completely different tasks. There are countless products that have been patented but have never been commercially marketed, either nationwide or locally.

If you have an invention, you should plan to do a patent search for three main reasons:

  • To help determine whether your invention is new. Even if you invented it on your own, someone somewhere may already have the same invention. You cannot assume your invention has never been patented even if you have never seen it on the market.
  • To document your invention's relationship to other inventions in the same field (the prior art). Almost all patents refer to earlier patents.
  • To familiarize yourself with patents. Reading a number of patents on similar inventions is a good way to learn how successful patents are written.

Be Prepared.
The process of patent searching is not overly difficult, but it does require significant amounts of time, concentration, and patience. Budget enough time to complete your tasks and take good notes along the way. If you are visiting the UW Engineering Library to begin your search, be aware that the library, computers, and/or reference staff might be busy on the day that you choose to visit or contact the library.  Be sure to check on reference/patent and trademark research assistance hours before visiting.  Please call or email the library prior to your visit for a brief overview of hours and services. Contact information:  phone 206-543-0741 / email
While reference and research help librarians may provide assistance with your search or provide general information, they cannot perform searches, evaluate searches, assist with applications, or dispense legal advice.

A step-by-step guide for searching patents by subject or by kind of invention:

PatFT, AppFT, PubEAST and PubWEST were retired on September 30, 2022. The new Patent Public Search (PPUB) is now available via the USPTO website.  Please note, some of the search guides, including the "Seven Step Strategy Guide (Detailed Handout)" still refer to PatFT, AppFT, and the other databases.  Use Patent Public Search.

The Seven Step Strategy (Multi-Step U.S. Patent Search Strategy) outlines a suggested procedure for preliminary patent searching. The steps shown are typical, but some may not apply to your search.

Seven Step U.S. Patent Search Strategy Guide (Detailed Handout - pdf)
You may want to print out a copy of this handout to keep with your notes and for later reference.

Search for Patents: USPTO patent search portal

Patent Public Search:

More information from the United States Patent and Trademark Office (USPTO):
The USPTO is the Federal agency responsible for issuing U.S. patents. The USPTO website provides access to information about the patent process, including patent searching and the patent application process: