“Hidden” legal status; Information sources on extra-territorial extension of patent rights

Legal status information is a critical component of many patent searches, particularly those conducted in industry. Although most major patenting authorities can provide reasonably comprehensive data on their own national legal status, this may not enable the user to obtain a complete picture of where patent rights are in force. Many smaller countries have a mechanism to recognise patent rights previously granted by other jurisdictions; however, the public information sources on these extensions are poorly controlled and difficult to access. A review is provided on the various means by which extra-territorial extensions may be obtained, and of the quality and quantity of public information which can be retrieved.