US Patent Reference, Number Only Field (REFN)

*NOTE* This field code is now deprecated.  Use FCITE which replaces both REFN and FREFN. FCITE returns both US and international citing documents in one query.  FCITE has a reverse counterpart, RCITE which also queries both US and international reverse (backward) references.

Even though it is deprecated, if you still want to use it, you can use the REFN field code to query patents that cite a particular patent number.

When you use it to query a collection of patents, REFN is useful to see who is citing your portfolio.


  • REFN:6000000  -->  Finds patents that cite patent US6000000.
  • (REFN:(US6519807 OR US6442791 OR US6991666 OR US7996956 OR US8495789 OR US7581285 OR US7610653 OR US7874040 OR US7757343 OR US6581239 OR US6519804 OR US6974488 OR US6553612 OR US7607196 OR US7581284 OR US8347454 OR US8646148 OR US8156609 OR US8112842 OR US8650708 OR US6709495 OR US7930799 OR US7600292 OR US8438699 OR US8522396 OR US8051531 OR US8650704 OR US7425225 OR US6818036 OR US8152878 OR US8021453 OR US8100999 OR US7186283 OR US7979959 OR US8510908 OR US7721385 OR US7278181 OR US8434193 OR US8474091 OR US8117712 OR US8516652 OR US8572802 OR US7513924 OR US7763090 OR US8375509 OR US8347455 OR US8572789 OR US8257457 OR US8182563 OR US8409335 OR US7628831 OR US7637991 OR US8387204 OR US7731770 OR US8302250 OR US6408481 OR US6010561 OR US6289553 OR US6231649 OR US5893936 OR US5840103) NOT ANO:(Dyson))

This second query is a really nice one.  Here's what is going on:

At the time of this writing, Dyson had 61 US granted patents that are related to vacuum dust handling and filtration.  Using the REFN query, and the OR operator between the patent numbers, you get a list of companies who cite the portfolio, and not just a single patent!  Notice at the end of the query, I removed self-citations using the short NOT assignee clause.  We are looking for outside companies that cite the portfolio.

The Dyson Example

The results of the Dyson query are shown in the example above.  I opened the Assignee (Original) filter/facet which hides part of the screen.  This is a list of companies who cite Dyson's dust filtering patents the most!  This list can be charted or exported from AcclaimIP, such as the example chart below.


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