Patent Classification System

Patent classifications are maintained by the patent granting authorities on their own classification schemes.

International Patent Classification (IPC)

The IPC (International Patent Classification) is one of the most important tools available to people who want to search patent databases. It divides the world of technology up into over 70 000 categories. Whatever your technical field, you can use the IPC to zoom in to patent documents relevant to your field of work.

The IPC is a hierarchical system, with layers of increasing detail. Here is an example:

G Physics
G02 Optics
G02C Spectacles, sunglasses or goggles ...
G02C5 Construction of non-optical parts
G02C5/14 . Side members
G02C5/20 .. Adjustable, telescopic

To know further about IPC, please read Guide to the International Patent Classification (Version 2009)

US Patent Classification

The US Patent Classification system is one of the most important national patent classification systems. It is heavily used today, because the economic importance of theUS patent system makes US patents a vital source for many prior art searches around the world. You can find the difference between US and IPC at Comparison between International and US Patent Classification. An automatic concordance tool to convert US classes to International Patent Classification (IPC) classes is also available on theUSPTO website.

US Patent classification number formats follows as CCC/SSS.sss, which represents Class number/Subclass number (Subclasses are usually 3 digits, but can be appended through the use of decimal points). There are several advantages to using the US patent classification system when searching US documents. n addition, it was the perception in the field at one time that the US classification system was revised much more frequently than the IPC system, and consequently that it was quicker when adapting to changing and emerging technologies.

European Classification (ECLA)

ECLA stands for European Classification, and was designed in-house by the EPO as an enhancement to the IPC classification system. The ECLA classification system contains 134 000 subdivisions.

The classification symbol is made up of a letter denoting the IPC section, followed by a number (two digits) denoting the IPC class (eg B62).
Optionally, the classification can be followed by a sequence of a letter (egB62J) denoting the IPC subclass, a number (variable, 1-3 digits, egB62J11) denoting the IPC main group, a forward slash "/" and a number (variable, 1-3 digits, eg B62J11/00) denoting the IPC subgroup.
Optionally, the EC subgroup may be added to the IPC symbol. It has the form of a letter, followed by a number (optional), a letter (optional), etc. (egB62J11/00B).

DEKLA Classification System

The DEKLA classification system is an internal classification system applied to German applications, patents, and utility models by German patent examiners. Like the European Patent Offices’ in-house ECLA classification system, DEKLA is based on the structure of the IPC (International Patent Classification) and represents further sub-divisions of IPC classes rather than a unique classification system of its own. There are 110,000 individual partitions in the DEKLA system, and about 70,000 come from the IPC.

DEKLA groups are extensions of IPC groups the DEKLA classes are formed by adding letters and numbers to the end of an IPC classification symbol. For example:

A

47

B

13

/

08

E1

Section

Class

Subclass

Main Group

Sub-Group

DEKLA section

British Classification System

This is the scheme applied in parallel to the IPC to all published British patent applications by the examiners at the Patent Office. It has been used since 1962. The British classification schedules are revised and republished periodically. Further information about the schedules is available on request from the Patent Office:

The British patent abstracts published weekly are arranged in subject matter groupings according to the British classification. File lists are available from the Patent Office which give the patent numbers of all specifications classified at a particular British classification code, or combination of codes. A charge is made for the lists and again further information is available from the Patent Office (tel. 0845 9 500 505). The British Library holds (at itsMicawber Street store) a massive file list in many volumes listing the British patents for each class from 1911 to 1962.