As a patent holder has the exclusive right to make, use, sell or import the invention, a new patent application would not be granted if the application contains the specifics resembles a granted patent. Therefore, a new patent applicant would usually conduct a patent research before filing the patent application to the U.S. Patent and Trademark Office (USPTO). Although this is not mandatory, as the USPTO would conduct the most comprehensive search in reviewing the application.
A patent search usually begins with a review of previously issued patents. Using the database offered by the USPTO, a patent applicant can find most patents he or she wants. Check here for the PatFT database, and here for the AppFT database. The two databases contain patents from different time periods. The USPTO also offers this seven-step strategy in assisting applicant to conduct a patent search.
[Last updated in September of 2020 by the Wex Definitions Team]