Research Guides: Patent and Trademark Resource Center (PTRC): Patent Searching

Searching for Patents

A thorough patent search will involve both keyword and classification searching and will cover both US and international patents. It will likely take a significant amount of time to conduct these iterative searches, so you will want to keep track of your searches (and relevant patents, as you find them).

Searching for Patents (Keywords)

How to Conduct a Preliminary US Patent Search (USPTO)
This is an overview tutorial from the USPTO covering how to conduct a preliminary US patent search.
European Patent Academy - Search strategies
A free e-learning course on 'Search Strategies' from the European Patent Office (who also maintain the Espacenet database).
International Patent Classification Search (WIPO)
This tool allows you to keyword search the International Patent Classification system, as well as the Cooperative Patent Classification System (an extension of the IPC).

Searching for Patents (Classification)

Patent Classification (USPTO)
This page from the USPTO discusses the US Patent Classification system (USPC) and the newer Cooperative Patent Classification system (CPC) and provides relevant resources to lean more and search these classification systems.
Cooperative Patent Classification
A tool from Espacenet, allowing you to keyword search the CPC system for relevant classification numbers associated with your subject area.
Classification Resources (USPTO)
This tool from the USPTO allows you to keyword search the CPC (2013-present) or the USPC (which was used pre-2013).
CPC Training (European Patent Office)
This site provides access to training modules jointly developed by the USPTO and European Patent Office on the Cooperative Patent Classification system.

Databases

Patent Public Search
This web-based tool from the USPTO allows you to search US patents. Basic Search allows you "to look for patents by keywords or common fields, such as inventor or publication number" while Advanced Search allows you to build complex and nuanced queries.
Google Patents
The Advanced Search tool allows you to search with a fair amount of specificity (see the question mark symbol next to 'Search' to see syntax options).
Espacenet
This search tool allows you to search completely worldwide, or worldwide for all patents filed in English.
PatentScope
This tool provides access to: "published International PCT applications in full-text on the day of publication,
patent documents from participating national and regional offices, [and] non-patent literature."
Free Patents Online
As well as search functionality (see the arrow next to the Search button to see 'Expert Search' options) FPO also provides the ability to browse recent patents by category.

Other Prior Art

Lens.org
Patent searching integrated with scholarly literature citations.

It is also a good idea to go back to the 'Patents' tab in this Guide and look at related guides, or contact the relevant subject librarian, for guidance on other literature sources related to your invention/idea.