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Searching the Derwent Class Code Field

Searches the Derwent Class Code field within a patent record.

Enter one or more three-digit class codes connected with search operators. You can enter complete codes or partial class codes using wildcards.

Alternatively, click the search aid link to look for specific codes to add to your search.

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About Derwent Class Codes

Patents are divided into 20 broad subject areas or sections. The sections are grouped into three areas:

• Chemical Sections (A - M)
• Engineering Sections (P - Q)
• Electrical and Electronic Sections (S - X)

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.

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Search Examples

• T04 AND V05 finds patent records that have a Derwent Class Code of both T04 and V05, which are both in the Electrical and Electronic Section.

• T04 OR V05 finds patent records that have a Derwent Class Code of either T04 or V05.

• T04 NOT (V05 OR V04) finds patent records that have a Derwent Class Code of T04, but not V05 or V04.

• M1? (same as M1*) finds patent records that have a Derwent Class Code starting with M1, which is the Metallurgy class of the Chemical Section.