How do I find relevant patents?

Searching for patents can be challenging because patents often use complex and varied legal and technical language. So keyword searching is likely to help you find some, but not all, relevant patents. 

A strategy called classification searching can help. Patents are organized into an international system of classification, or categories, called Cooperative Patent Classifications (CPC). If you can find the relevant CPC class for your project, you can more easily see what ideas have been patented related to your topic, anywhere in the world, even if different terms have been used to describe them. You'll also likely have fewer irrelevant results to look through.

Start by brainstorming keywords that describe your idea.

Think about what you are looking for and its function (what does it do?), composition/structure (what is it made of?), and intended use (what is it used for?). 

You can use those terms to create an effective search using AND to bring back multiple concepts in your results - for example, stent-graft AND coating. You can also use OR to include synonyms, so that your search captures more results - for example, stent-graft AND (coating OR adhesive OR polymer). Remember to think about alternate spellings and abbreviations. It's also best to avoid brand names, as they are trademarked separately and not likely to be included in patents.

Then, use those keywords to search by classification. 

You can also use those keywords to find the relevant CPC class, so that you can browse a more targeted category of patents. There are searchable CPC lists available in several patent databases, including Google Patents, USPTO, Espacenet and Lens. Once you've found relevant CPC class(es), you can search for it in multiple patent databases to make sure you're not missing any relevant patents.

USPTO's Seven Step Strategy is a helpful guide to combining keyword and classification searching into a thorough patent search.

And remember, searching is an iterative process. Try a search, evaluate your results, and adjust your search accordingly. And if you need help, ask a librarian!