Searching the Cited Patent Number - Expand to Include Family Field

Expand your search to include all patent numbers found within a patent family by selecting this field.

You must enter a unique patent number when using the Expand Family option. For example: EP178925 or EP178925-A

Do not enter a partial patent number with a wildcard as this type of query results in an error. For example: EP1789* and EP17892? are not valid searches because the patent number could be found in more than one family.


Using the Expand to Include Family Option

The results of a Cited Patent Number Search using the Expand Family option may differ from the results of a typical Cited Patent Number search.

For example, the search query CX=EP178925-A returns more records that cited this patent record than CP=EP178925-A because you have expanded your search to include patent numbers found within a family of patents.


Patent Family

A patent family is a set of individual patents granted by various countries. Think of a patent family as all the equivalent patent applications corresponding to a single invention, covering different geographical regions.

As applications are made for patents of an invention in countries around the world, Derwent links these patents together into a patent family structure. Derwent then tracks the development of the patents, indexing all updates received from the various international patent authorities.


Cited Patent Number + Family Examples
  • EP797246 finds patent records that cite patents with the patent number of EP797246 (any status code), along with patents that cited any patent that belongs to the same family as EP797246.

  • EP797246 OR US5723945-A finds patent records that cite either patent EP797246 or US5723945-A or both patents (any status code). This search also retrieves patents that cite any patent that belongs to the same family as either EP797246 or US5723945.

  • US5723945-A AND EP797246 finds patent records that cite both of these patents (any status code).