Patent Classification Concepts
A patent classification system is an organization structure that permits the efficient retrieval of relevant patents. Knowledge of patent classification system is essential for thorough, timely searches. The US Classification System currently contains 464 classes including all utility, design and plant classes. Sporadic reclassification projects take place that modify the system, usually by adding subclasses and, sometimes, classes. The International Patent Classification or "IPC" (and the related European Classification or "ECLA") contain 8 sections: A thru H. Each section contains 5 to 36 classes and 30 to 166 subclasses; each subclass is further divided into groups and subgroups. ECLA includes all of IPC and, in some groups and subgroups, is yet further subdivided. The IPC is updated periodically (about every several years) and issued as an "edition", currently Seventh Edition. ECLA is updated more frequently depending on the needs of examiners in the European Patent Office that has several locations including Munich, Berlin, The Hague, Stockholm, Vienna and Rome. Other patent classification systems include F-term (usable for searches of the Japanese patent database provided by the Japanese Patent Offic); and, Derwent (usable on WPI database available to subscribers). Other non-patent classification systems include PACS (for searching journal documents in the database of the American Physical Society); Library of Congress for searching for technical resources in the LOC (loc.gov web site) and in the technical information centers at the USPTO; and CAS (for chemical structures and using Chime).
Chemical structures
Organic chemicals US Classes
Metals and alloys US Classes
Ceramics US Classes
General and Miscellaneous US Classes
Chemistry IPC