PatentSearch

Official Gazettes, Annual Indexes (of Inventors), the Manual of Classification and its subject matter index, and other search aids are available in various formats. Patent assignment records of transactions affecting the ownership of patents, microfilmed deeds, and indexes are also available.

The Patent Search Room is open from 8 a.m. to 8 p.m. Monday through Friday except on federal holidays.

Many inventors attempt to make their own search of the prior patents and publications before applying for a patent. This may be done in the Patent Search Room of the USPTO, and in libraries, located throughout the United States, which have been designated as Patent and Trademark Depository Libraries (PTDLs). An inventor may make a preliminary search through the U.S. patents and publications to discover if the particular invention or one similar to it has been shown in the prior patent. An inventor may also employ patent attorneys or agents to perform the preliminary search. This search may not be as complete as that made by the USPTO during the examination of an application, but only serves, as its name indicates, a preliminary purpose. For this reason, the patent examiner may, and often does, reject claims in an application on the basis of prior patents or publications not found in the preliminary search.

Those who cannot come to the Patent Search Room may order from the USPTO copies of lists of original patents or of cross-referenced patents contained in the subclasses comprising the field of search, or may inspect and obtain copies of the patents at a Patent and Trademark Depository Library. The PTDLs receive current issues of U.S. patents and maintain collections of earlier issued patent and trademark information. The scope of these collections varies from library to library, ranging from patents of only recent years to all or most of the patents issued since 1790.

These patent collections are open to public use. Each of the PTDLs, in addition, offers the publications of the U.S. Patent Classification System (e.g., Manual of Classification, Index to the U.S. Patent Classification System, Classification Definitions, etc.) and other patent documents and forms, and provides technical staff assistance in their use to aid the public in gaining effective access to information contained in patents. The collections are organized in patent number sequence.

Available in all PTDLs is the Cassis CD-ROM system. With various files, it permits the effective identification of appropriate classifications to search, provides numbers of patents assigned to a classification to facilitate finding the patents in a numerical file of patents, provides the current classification(s) of all patents, permits word searching on classification titles, and on abstracts, and provides certain bibliographic information on more recently issued patents.

Facilities for making paper copies from microfilm, the paper bound volumes or CD-ROM are generally provided for a fee.

Due to variations in the scope of patent collections among the PTDLs and in their hours of service to the public, anyone contemplating the use of the patents at a particular library is advised to contact that library, in advance, about its collection, services, and hours, so as to avert possible inconvenience. For a complete list of PTDLs, refer to the USPTO Web site at www.uspto.gov/web/offices/ac/ido/ptdl/.