The Unites States Patent and Trademark Office publishes their own guide to conducting a patent search on the USPTO’s website. I’ve broken down the steps suggested by the USPTO into three different stages to make things easier to remember.

Step 1: Brainstorming Keywords

The first stage of the patent search is the keyword discovery stage. In this stage, brainstorm various keywords that might be contained in prior art documents that disclose your invention.

When brainstorming keywords, include industry specific terms as well as generic terms. The search function at the Patent Office website cannot distinguish between the two. Moreover, the search function does not include synonyms. Try to be inclusive in this stage.

You may have found, if you have already attempted a patent search, that the search result contains numerous irrelevant references. The reason is that certain words might have different meanings in different industries. The search function does not place words into context. It is a pure text string search.

Step 2: Class and subclass look up

The second stage attempts to limit extraneous or irrelevant search results by searching within one or more classes or subclasses. The USPTO classifies each patent document within one or more of 450 different classes. Within each class, there are multiple subclasses – literally hundreds or thousands of subclasses per class. As a result, the subclasses are detailed subdivisions and categorize different aspects of the class at the granular level.

If a search is made within the right class and subclass, then irrelevant references are less likely to show up in the search results. The downside is that the all of the right classes and subclasses must be searched. To ensure that all of the right classes and subclasses are found, the search process must be treated as an iterative process. After relevant references are found, the classes and subclasses of those references are checked to determine whether all relevant references have been found.

Step 3: Search patent and published application databases

The USPTO maintains two different online databases, namely, a database of issued patents and a database of published patent applications. Both databases must be searched because although there is an overlap, they both have their own unique set of references. Not all patent applications mature into a patent. Hence, published patent applications that have not matured into a patent will not be found in the issued patents database. Also, not all issued patents were published as a patent application. The inventors could have submitted a request for non publication. These patents will not be found in the published patent applications database. Another way to streamline this step is to conduct the search on a third party site such as www.freepatentsonline.com. Utilize the advanced search and be sure to check the boxes for patents and patent applications. This should reduce your work in half.

While a review of the references found through the search process is made, you will find additional keywords and other potential class/subclass for further search and consideration. The above process is repeated for those additional keywords and classes and subclasses.

I invite you to contact me with your patent questions at (949) 433-0900 or [email protected]. Please feel free to forward this article to your friends. As an Orange County Patent Lawyer, I serve Orange County, Irvine, Los Angeles, San Diego and surrounding cities.