An Incredible Free Patent Citation Search and Analysis Tool: The CCD

[tweetmeme source=”Intellogist” only_single=false] Citation search and analysis tools are available in many subscription patent databases; PatBase allows users to view both patent and non-patent literature citations for entire patent families, and users can view the citations graphically through “citation trees.” A July 2011 update to PatBase added the additional features of a citation timeline and citation line graph.

Wouldn’t it be fantastic if there was a patent citation tool, with similar functions to the PatBase citation features, that was also free?  Thanks to the EPO, JPO, and USPTO, such a tool now exists.  The Common Citation Document (CCD) allows users to view documents cited by the EPO, USPTO, JPO, and PCT citations for patent families related to a specific patent application.  The CCD application includes the capability to view full-text of cited patent documents, the division of cited documents in a list by source of citation and connection to a specific patent application, the category of relevance for EPO citations,  a compilation of “classifications and fields searched” for an entire patent family, and a timeline view to illustrate the time span for a collection of citations.

Read on for a detailed description of the coverage, features, and functions of the CCD application!


The EPO website described the CCD as:

a patent information tool developed by the Trilateral Offices to provide single point access to citation data for their examined patent applications.  It consolidates the prior art cited by all participating offices for the family members of a patent application, thus enabling the search results for the same invention produced by several offices to be visualised in a single page.  It currently includes data from the Trilateral offices: the EPO, the JPO and the USPTO.

According to the CCD help guide, citation data available through the CCD includes: [1]

  • EP citations – Both patent and non-patent citations and covers all possible procedures: applicant citations, search citations, examination citations, observations by third parties and opposition citations.
  • US citations – References to both patent and non-patent citations and covers only applicant and search citations.
  • JP citations – References to patent citations and covers all search, examination, opposition and appeal procedures, but does not include applicant citations.
  • WO citations – References to both patent and non-patent citations and covers only applicant and search citations.

Search and Display Features

Within the search form on the CCD homepage, a user can enter a publication number, application number, or priority number. Basic bibliographic criteria (like applicant name, inventor name, publication date, and ECLA class) is also accepted in the search form, and the user may only use the AND operator when joining search terms.[1] After searching for the document, the system will either retrieve a document directly, which will be loaded in its own tab, or the system will generate a list of choices to select from. Multiple tabs (with a document result list displayed under each tab) can be open within the application.

According to the help guide, “the CCD web application outputs the simple patent family first”, and to retrieve the extended family, the user must select the button “Get all family members.” Simple family groupings are indicated in a CCD viewer list “of lookup results with alternating white and gray background shading.”[1] On the left side of the screen, the CCD viewer pane lists all family applications and related citations (grouped by simple families). Under each application name (which lists the country code, “‘Application N°’ followed by the EPO application number and the domestic application number in parentheses and the filing date associated with the family member”), users can expand a list of citations. The citation information includes the category of relevance, details on the relevant sections within the cited document, and the claims of the original document to which the citation document is relevant (“this information is only available for searches performed at the EPO, e.g. EP or WO where the EPO has acted as International Search Authority”).[1] The citations for each application are arranged under search type/who cited the document (i.e. National Search Report, National Examination, Applicant, etc).

A list of all citations for a patent family. The list is in the left pane, and the bibliographic data for a specific cited patent document is displayed in the right pane.

If a user selects a family member application or cited patent document within the CCD viewer, they can view the bibliographic data (including abstract) for the document in an adjacent screen. Within the adjacent screen, the user can also view the description, claims, and original document (which the user can navigate through page by page). Users can’t view non-patent literature citations in the adjacent panels.

The list of cited documents for a patent family is in the left pane, and the original document for a specific family member is displayed in the right pane.

Within the CCD viewer panel, user can select:

  • Citation only view – Instead of arranging citations under each application, a list of citations is presented with the relevant application noted in a separate column. Additional option in this view to “group across extended families.”
  • Compact/Expand View – Show or hide all citations under each application.
  • Sort by country – Sort application list by country.
  • Filter – Options to “hide applicant citations” or “hide applications without citations”.
  • Classification and fields searched – In the panel to the right of the CCD viewer, the user can view a compilation of classifications (“technical domains in which the subject-matter of such a document belongs”) and “fields searched” (“technical domains in which the search for each family member has been performed”).[1] The classifications/fields searched are arranged under country codes (related to family member applications). This list applies to the entire family, and not individual family members.

Above these CCD Viewer options are additional options:

  • Hide/Show the CCD viewer.
  • Double Inspector/Single Inspector – Users can view one or two panes adjacent to the CCD viewer. Most documents will appear only in the first adjacent pane if the double pane option is utilized, but the “Timeline” view gives users the option to view a citation in pane 1 or pane 2.
  • Timeline – The Timeline “graphically shows the timespan for a collection of citations, such as relevant priority, filing and publication dates of a patent application.”[1] Users can select from three timeline modes:[1]
    • Default or “simple” – Gives the full view of the citations surrounding the input criteria used for a CCD lookup.
    • Single application mode – Pares down the data down to one application and related prior art.
    • Compare mode – Uses a circular list for comparing up to 4 applications in the timeline — indicated with color coding and their related citations.

The timeline view in the far left pane (in compare mode) with two specific documents viewed in two adjacent panes.


Although the CCD application may not have the broad citation coverage of PatBase or the variety of visualization features for citations (such as the “citation tree”), the CCD still provides a solid coverage of citation data for three major patent authorities (USPTO, EPO, and JPO), as well as PCT citations.  Like the PatBase citation feature, the CCD allows users to view citation data for both entire patent families and individual family documents, and the CCD additionally provides the the category of relevance, details on the relevant sections within the cited document, and the claims of the original document to which the citation document is relevant (for EPO citations).  The CCD application is a tool that may be useful not just as an alternative to subscription-based citation features but as a supplement, since it provides additional data for EPO citations.

Do you know of other free or subscription patent citation search and analysis tools?  let us know in the comments!


[1] – “Trilateral-CCD Help (v1.10).” CCD website, Accessed December 29, 2011.

Patent Information from Landon IP

This post was contributed by Joelle Mornini. The Intellogist blog is provided for free by Intellogist’s parent company Landon IP, a major provider of patent searches, trademark searches, technical translations, and information retrieval services.

3 Responses

  1. Espacenet also has forward (citing) and backward (cited) citations in the left hand menu for individual applications. I assume they aren’t the family citations though.

    • It looks like the cited documents on Espacenet are only for that particular patent document. I just searched for application EP0803098 (A1), and that record only lists one cited document, a US patent application. If you search EP0803098 (A1) within the CCD, it displays the citations for 7 family members (or 11, if you merge two simple families). Either way, there are many more citations listed for the entire family on CCD than just for the single document on Espacenet.

  2. […] An Incredible Free Patent Citation Search and Analysis Tool: The CCD (The Intellogist Blog) […]

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