Searching the Derwent Class Code Field
Searches the Derwent Class Code field within a patent record.
Alternatively, click the search aid link to look for specific codes to add to your search.
About Derwent Class Codes
Patents are divided into 20 broad subject areas or sections. The sections are grouped into three areas:
They are subsequently divided into 20 broad subject areas or sections. These sections are then further subdivided into classes. Each class consists of the section letter, followed by two digits. For example X22 is the class designation for Automotive Electrics and C04 is the class for all Chemical Fertilisers.
When used in combination with other search fields such as a Topic search, these classes allow you to precisely and effectively restrict your search to the relevant subject area.