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U.S. Patent Databases

The best free U.S. patent databases are:

USPTO Patent Databases

The official United States Patent and Trademark Office site includes access to the full-text of patents from 1976-. Full-page images of patents are included from 1790-.

•You may need to download a specific TIFF image browser plugin to view the actual page images of the patents (be sure to read the directions)

•Use the "Advanced Search" link on the front page for more complex searches.

Google Patents

Google Patents provides an easy way to search U.S. patents from the USPTO database. Keyword and phrase searches use the familiar Google box. Once found, you can read the patent on the screen or download a PDF of the patent.

The advanced search page also allows you to search by patent number, title, inventor, assignee, U.S. classification, international classification, document status, patent type, issue date, and filing date.

freepatentsonline

This site provides another way to access the USPTO patents, as well as other patent databases. The site is easy to search and has some nice display features. Its advanced search is robust and powerful.

You can search it here now:

Delphion Intellectual Property Network

The Delphion Intellectual Property Network is another source for searching the USPTO information. You may find the Delphion site easier to use than the USPTO site. You must register in order to use the free portions of this Web site. This site also provides many additional services for a fee.