How to do a Patent Search

How To Do A Prior Art Search.

How to do a patent search. The patenting prior art searching basics from a patent search firm. How to start and conduct a prior art or patent search.

A prior art or patent search is conducted to identify the prior art for an invention. The novel and non-obvious elements of a patentability study are determined for an invention based on its prior art. The prior art search is an essential first step on the steps to patent. Professional patent practitioner help is highly recommended to evaluate whether an invention is novel and non-obvious.

A patent search comes down to basic research

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How to do a patent search. A basic patent search (prior art search) is researching various data sources. It is determining if there is prior art that discloses your invention. Prior art includes existing patents, patent applications, and non-patent literature. It can be found anywhere around the world. Prior art is any existing documents that show or describe the invention. However, it can also be things that are similar. Anything that describes how to make and use an invention is prior art.

In other words, a prior art search is research looking to find a disclosure of your invention. This is important because a disclosed invention is no longer novel. A consequence of not being novel is that the invention is not patentable. Therefore, no patent will be allowed, or issued, if the invention is already disclosed.

Important Tip: An inventor has 12 months from the date of public disclosure of an invention to file a claim for a patent. In other words, a disclosed invention is its own prior art 12 months after it is disclosed to the public.

There are three basic elements of input for the search engines. To do a patent search, you will need the following three things:

  • A good description of the invention.
  • A list of keywords about the invention.
  • A classification for the invention.
The Things Needed To Do A Search


The place to start a patent search is with the description of the invention. A description of the invention that is just a simple sentence or two is the easiest to work with. A concise description is best. This is because what you will need for actually searching in databases is just the right few keywords and the right classification(s). When searching, look for any existing products and processes that are similar to the invention.


When considering how to do a patent search, the description is used to develop a good set of keywords. Then, the keywords are the words that are used for database searching. The best keywords to use are those terms and phrases about the invention and its field of use that describe it most accurately and completely. When searching, a good concise description is simpler and easier to use than a long explanatory one. Further, the concise description likely already has most of the keywords needed to start and do a search. In addition, too many synonyms can become confusing.


The final piece of input for how to do a patent search is the classification search. You need to do a classification search. In other words, you need to search the various classifications that the invention is likely to be put in. The classification system to use is the CPC Scheme (CPC website). The CPC is the Cooperative Patent Classification system. The CPC (like all classification systems) categorizes inventions into classes. The idea, then, is that all the other inventions that are like an invention will be in the same class(es). Thus, searching the likely classes is essential to a good patent search.

Important TIP: If you don’t know or can’t find the class(es) for your invention, one easy place to start is the class(es) of similar patents found when searching. First, find similar prior art. Then, use that classification as a starting point for the new invention.

where to DO the searching

Steps To Patent Search

The simple version of how to do a patent search. There are 3 basic steps for starting and conducting a patent search. This is a basic method for starting a prior art search is conducting a database search for an invention. For example, enter keywords or classifications as search input. Then, review the list of search results.

1. Keyword searching in one place

Step one in how to do a patent search is to use the keywords to search. The easiest databases to search in are the Espacenet and Google Patents databases. Pick just one to start with. Enter keywords into the search entry text box. Look for products or processes that are similar to or describe your invention. Read the abstract and claims. If it mentions things that are close, read deeper into the document. Additionally, for potentially relevant items that are found, be sure to download copies for later reference and study.

2. Refine the keywords, and add classification searching

After the initial search, review the results. Read the collected prior art. Then, assess, evaluate, and refine keywords, phrases, and classification(s) to narrow the results. Look for those products or processes that are similar to the invention. The more specific the keywords and phrases, the better the search results will be.

Search step 2 includes a classification search. Where an invention has several likely classes, it is best to search them all. Searching by class is entering the class into the search engines and reviewing the results for prior art. Use the classes from the prior art if the invention is not more formally classified.

3. Search all of the places (data sources)

After reading and refining keywords and classifications, the third search step of doing a patent search is to search all data sources (places) to be searched. An exhaustive search includes databases from many countries in many languages. There are over 100 searchable data sources. Prior art can come from anywhere. At a minimum, the databases listed above should be searched. In other words, this is a basic patent prior art search. A more complete search includes searching in related areas and searching into more data sources.

How to do a patent search Important TIP: Proper searching is essential to good patent specification writing. Specifically, searching guides good claim writing by finding existing similar claims. Well written claims improve the protection the patent provides.

Patent Practitioner Help Recommended

The United States has specific criteria. Whether it be a patent, patent application, or other disclosure that may be relevant, prior art can get complex. For example, in certain circumstances, an earlier disclosure by the same inventor may be excusable, or prior art. In other circumstances, an application filed earlier, but published later than your application, may be cited against your application. 

Patenting is complex

Prior art searching and patentability determinations are time consuming and complex tasks. Additionally, all patents, patent applications, and non patent literature from around the world need to be examined and considered in an exhaustive search. An exhaustive search includes searching in other related fields. When considering how to do a patent search, other related fields are areas of potential use or related technologies that may be applicable.

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Important TIP: When looking for expert patenting services help only a patent attorney or patent agent can prosecute patents for you.