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The Espacenet patent family ("worldwide service")

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In the "worldwide" database in Espacenet all keyword searches must be in English, and the representative documents displayed (abstract, description and claims) are also in English.

Whilst English is the language most frequently understood by users in general, there are many who would prefer to use an alternative language in order to gain an in-depth understanding of the technical content.

The same invention can be the subject of a number of applications worldwide, in a variety of languages. In such cases, there may be a document describing the invention in a language other than English.

We try to help in this matter by prompting the user with the equivalent documents that we have available in the EPO's systems. Since in Espacenet the philosophy is to display very similar documents in various languages, we have tried to be as certain as possible that what we prompt the user with really has the same technical content. The best way of doing this is to take the "equivalent rule" as our criterion.

Definition of the Espacenet equivalent

The equivalent rule in Espacenet is that, for two documents to be described as equivalents, all their priorities must be the same.

Readers should note that even this rather strict rule provides no guarantee that the two documents will be the same.

It is also important to note that for many people, a patent family is a list of roughly similar patent documents (linked by priorities) from throughout the world. It is used by those who wish, for example, to establish the geographical coverage of a particular patent. This definition is not the one used in Espacenet for defining equivalents (see above).


The Espacenet patent data contains several special features:

  • Standardisation of document, application and priority numbers
  • The IPC (International Patent Classification) is checked and standardised
  • ECLA (European classification system) classes are appended to all documents and permanently updated
  • There is an ongoing correction process for priority numbers

In the following case, documents D1, D4 and D5 have no equivalent, while D2 and D3 are equivalent. 

Document D1 Priority P1     FAMILY P1
Document D2 Priority P1 Priority P2   FAMILY P1-P2
Document D3 Priority P1  Priority P2   FAMILY P1-P2
Document D4   Priority P2 Priority P3 FAMILY P2-P3
Document D5     Priority P3 FAMILY P3

Example of Espacenet equivalents:

US5402857 Oil and gas well cuttings disposal system
Publication number: US5402857
Publication date: 1995-04-04
- international: B63B35/44; E21B21/06; E21B41/00; B63B25/02; B63B35/44; E21B21/00; E21B41/00; B63B25/00; (IPC1-7): F21B21/06; B09B5/00
- European: B63B27/20; B63B35/44; E21B21/06N2C; E21B41/00M
Application number: US19940197727 19940217
Priority number(s): US19940197727 19940217
Also published as: US5564509 (A1), NL9500301 (A), GB2286615 (A), NL194733C (C), CA2142536 (C)

A search for US5402857 retrieved the document itself plus five equivalents (from Canada, the UK, The Netherlands and a domestic equivalent (see example)). Meanwhile, the "extended" (INPADOC) family system will retrieve 81 documents for the same priority, because in the EPO's raw data resources (INPADOC) a much broader family definition is used.

How to find a broader patent family using Espacenet

Simply click on "view INPADOC patent family" to retrieve the full extended family. INPADOC's strength is that it retrieves complete families automatically, irrespective of their complexity. Read more information on the "extended" (INPADOC) patent family.

Espacenet reference documents

In the Espacenet results list (hit list), all the documents retrieved from searching in the worldwide data collection or the Japanese data collection have a reference document. The reference document (wherever possible in English) is the representative document of the patent family to which the selected document belongs.

What criteria are applied when choosing a reference document?

When choosing a reference document in English, the EPO applies the following order of priority:

  1. Firstly, the EP document in English
  2. If unavailable, then the first US document published
  3. If unavailable, then the first GB document published

If, one month after publication, a document still does not have a reference document in English, the EPO will arrange for translation of the title and abstract, provided that the document belongs to the minimum PCT documentation. Otherwise, no translation will be made. 

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