For more technical patent searches, contact the the Denver Public Library Patent and Trademark Resource Center. As the only designated Patent & Trademark Resource Center (PTRC) in Colorado, The Denver Public Library provides free access to patent and trademark resources in various formats, and reference librarians provide assistance and instruction on how to perform a preliminary patent and trademark search.
Espacenet is a free service on the internet provided by the European Patent Organisation through the EPO and the national offices of its members states. Access published patent applications with an English abstract and title from over 30 million documents. Over 150 Million full text pages are available for download.