Patent search
Also called patent information search, patent searching
Patent search is a search of patent documents, and often non-patent literature, to answer a defined question: what is known in a field, whether an invention is new, whether a product may infringe in-force patents, or whether a granted patent is valid1.
Patent information is the technical and legal information in patent documents, and covers both granted patents and patent applications1. Once the objective is known, the searcher selects the databases suited to it, collects the patent documents and analyzes them1.
Types of patent search
WIPO's patent information module groups patent searches by the question they answer1. WIPO's Technology and Innovation Support Centers list four of these types as on-demand specialty searches: novelty or patentability, state-of-the-art, freedom to operate, and validity or invalidity2.
| Search | Question it answers | When it is done |
|---|---|---|
| State of the art | What is known across a defined technological field?1 | Mainly at the start of new R&D projects1 |
| Patentability | Is a defined invention new and non-obvious?1 | While preparing and before filing a patent application1 |
| Freedom to operate (infringement) | Would launching a product infringe unexpired patents?1 | During technical and product development, and before marketing1 |
| Validity | Was a granted patent properly granted?1 | After grant: for litigation, licensing negotiations or due diligence1 |
| Index or name search | Which inventors, researchers or companies hold patents, and which equivalents exist in other countries?1 | When identifying leading inventors or companies in a sector, or finding an equivalent patent in a known language1 |
A search for evidence to support an opposition before a patent office is covered under opposition search.
How a patent search is run
The USPTO publishes a multi-step strategy for a preliminary US patent search3.
- Brainstorm termsList words that describe the invention, including alternative words for the same concept3.
- Run a keyword searchStart broad with the main concept, narrow by adding further features, and screen the front pages of patents and published applications3.
- Review the closest documents in depthRead the drawings, specification and claims of the most similar documents3.
- Expand with classificationFind relevant Cooperative Patent Classification (CPC) codes and run a classification search3.
- Broaden beyond US patentsSearch foreign patents and non-patent literature such as books, journals, websites, technical catalogs and conference proceedings, or have a patent professional review the search3.
- Record the searchNote the databases used, the date and time, the keywords and the documents retrieved3.
Where to search
Many national patent offices offer free patent databases that are open to the public1.
United States
Europe
- Espacenet is free and contains data on more than 150 million patent documents from around the world, from 1782 to today, updated daily6.
- The European Patent Register gives procedural and legal information on European applications from publication, and on Unitary Patents, with links to national registers for status after grant7.
International
Limits of a patent search
- Free tools. WIPO notes that free services work well for simple searches but are not suitable for more complex investigations and legally motivated searches1.
- Completeness. WIPO states it is generally wrong to assume that a search on free databases is comprehensive, and that a comprehensive patent search is usually a job for an expert1.
- Time lag. There is always a time lag between an invention and the publication of its patent application, so applications not yet published cannot be found1.
- Legal status. A document in the results may no longer be in force. Espacenet provides supporting information on whether a patent has been granted and is still in force6.
Questions people ask
Search before filing
Novelty Search AI Agent
An AI agent that searches prior art for your invention and compares each reference with it feature by feature.
Run Novelty SearchWhat are the main types of patent search?
WIPO describes state of the art, patentability, infringement (freedom to operate), validity, and index or name searches, each answering a different question1. WIPO's support centers offer novelty or patentability, state-of-the-art, freedom to operate and validity or invalidity searches on demand2.
Can I search patents for free?
Yes. Official free tools include the USPTO's Patent Public Search4, the EPO's Espacenet6, WIPO's PATENTSCOPE8 and CNIPA's Patent Search and Analysis Service9. WIPO cautions that a search on free databases should not be assumed to be comprehensive1.
How it connects
Go from the term to the task
Read how the method works, run it on your own product or idea, then try a free tool.
- 01 / How-toPatent landscape analysis: a working guideFrom search strategy to the charts that answer a business question.Read
- 02 / AI agentNovelty Search AI AgentAn AI agent that searches prior art for your invention and compares each reference with it feature by feature.Run it
- 03 / Free toolAI prior art searchDescribe an idea, get the closest patents.Try tool
More next stepsPatentability search: a practical guide