Patent Searching

There are several different ways of searching for a patent. See below for each strategy. 

Searching the USPTO database

By Patent Number: 

1. Go to the USPTO Patent search database
2. Click Basic search
3. Enter the patent number in the search field

By Subject: 

1. Go to the USPTO Patent search database
2. Click Basic search
3. In the Basic search section - enter keywords that describe your patent and find one that is similar to what you're looking for
4. Note the Cooperative Patent Classification (CPC) number/Subclass for that patent, e.g. A07D 711/113 .
5. Perform a search in the database using that Class/Subclass 
6. Explore that category of patent! 

By Keyword:

1. Go to the USPTO Patent database
2. Search via keyword
3. Make note of any other common use keywords 
4. Combine and refine your keywords to get closer to the patent subject you're looking for

You can also explore the WIPO database for catchwords and ideas for how to search. 

Espacenet is the European Patent Office's free database that houses international and U.S. patents. 

How to search:

By patent number:

1. Go to Espacenet
2. Enter the patent number (with or without the country code)
3. Choose the patent that you are looking for with that number 

By subject: 

1. Go to the Espacenet advanced search
2. Enter your keywords in the title/abstract search field
3. Identify a patent that is close to what you're looking for
4. Make a note of the International Classification number/Subclass for that patent, e.g. H04B1/59.
5. Do a Class/Subclass search at the Espacenet Classification search
6. Gather any relevant patents to your project for further review 

Reminder: Many of these patents will be in different languages that may or may not have translations available. Keep this in mind when searching. 

When searching for prior art there are 7 steps to keep in mind to help you find what you're looking for. Remember that search prior art typically means that you're looking to submit a patent and want to make sure that no one else has already patented your idea or something very similar. This will save you time and money! You do not need to be a patent attorney to do so!

1. Brainstorm search terms - think of multiple ways to describe your invention. Come up with a list of what your invention is and what function it serves
2. Search the USPTO Patent Public search using those key terms. Remember to check the CPC classification lists to generate keywords
3. Do an in-depth review of all of the patents that fall within the scope of your own idea 
4. Expand on your search using any CPC classification terms to aid you in finding relevant results 
5. Review any cited references that are located at the top of the patents that you have deemed close to your own invention
6. Expand your search by checking other patent databases - Patent websites, Google Patents, Espacenet, Etc. 

If you have suggestions for how to make this page better, please contact Elizabeth Jerow, Library Director (jerow@msoe.edu).