Patent classification

Patent databases contain a wealth of information about technology, and with over 70 million patent documents the EPO's Espacenet worldwide database is one of the largest collections of technical information in the world. To make searching easier, patent applications are classified by technical area.

Here we look at current issues in patent classification, including efforts to harmonise classification systems and the tagging schemes developed by the EPO to identify technologies that span multiple technical fields.

Cooperative patent classification

Europeans and Americans are developing a unified patent classification system which could revolutionise how they work and how applications are filed.


Its interdisciplinary nature means that the literature – especially patent documents – is difficult for searchers to retrieve. The EPO has therefore introduced "Y01N" tags to label nanotechnology in EPO databases. Recently Y01N became B82Y.

Clean energy

The EPO has also established a new classification ("Y02") to cover what can be loosely referred to as "clean energy" technologies – a specific sub-sector of climate-change mitigation technologies.

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