The international patent classification as a search tool

Many databases contain information on patents, which can be searched as any other kind of literature. Additionally, however, on all patent documents are printed one or more symbols of the International Patent Classification (IPC), which are recorded in the online files. This paper first gives some background information on the IPC, its change in the course of years, then concentrates on the practical aspects of using the IPC as a search tool. Examples are given based on the author's own experience. Attention is drawn to pitfalls connected with IPC searching and to ways of combining the IPC with other search parameters. It is not the purpose of this paper to criticize the IPC or to express views on its future.