A Patent and Trademark Depository Library (PTDL) is a library designated by the U.S. Patent and Trademark Office (PTO) to receive and house copies of U.S. patents and patent and trademark materials, to make them freely available to the public, and to actively disseminate patent and trademark information. For more information, see www.uspto.gov/web/offices/ac/ido/ptdl/ptdlib_1.html.