AOP Community Resources

NPL as Prior Art


Non-Patent Literature can be very useful as prior art, but it functions very differently from patents.  Most of the time, they outperform patents in terms of the scope, specificity, and relevance of the information they provide as prior art.  As a driver of new leads, NPL can provide value when it cites other NPL, whereas patents primarily cite other patents in similar areas of technology.

Note that the standard for the grant of a patent is quite different from those set by editors of scientific or engineering journals.  As required by patent law, a patent must disclose the invention in sufficient detail to enable a practitioner in the field to replicate the patented invention without too much experimentation.

On the other hand, a major requirement by NPL publishers, such as those from science and engineering fields, is that the findings of a study being reported for publication in a journal must not have been previously published.  The extent of details provided in the final version of an accepted journal article normally depends on the reviewers of an article, rather than on general rules set by the publisher.

In addition, patents, especially those on important inventions, are almost always a ripe target for litigation.  Failure to comply with the legal standard set by patent law and USPTO rules can exact too high an actual or potential monetary penalty to a patent owner, especially when one or more patent claims are invalidated.  To authors of NPLs, the worst-case-scenario is a rejection of their paper by a journal.

NPL Dates

When you find a potentially relevant NPL reference, the first step is to inspect the publication date and verify that it is indeed eligible based on the Study LDR.  When the publication date of an NPL is even just a day older than the LDR, that reference would no longer be considered prior art, although it may be useful in continuing your search for other references.

If there is not a clear publication date on an NPL reference, the primary solution is to identify the publisher or find a direct link to the publisher’s website.  The publisher’s web page is much more likely to contain the official publication date, often phrased as, “Originally published on…” or “First published on…” followed by the online posting date of the reference.

Unless the online posting date of the NPL is the same as its publication date on the print-version of the journal, one should always cite the earlier of the two publication dates (online posting date vs. print publication date).  In the case of articles initially published in an electronic journal, the online posting date would normally be earlier than any print publication date of the same NPL.  In any case, one should cite the earlier of the two dates, assuming the earlier date at least is before the LDR.

When the publication date is completely unavailable, it is helpful to also include the URL of the reference, in addition to the official publication dates posted on the publisher’s website, when uploading the NPL to the AOP Study’s web page.

NPL Relevance

The downside to NPL is that the language can be very hard to understand because it is intended for the practitioners in the given field.  Be prepared to look up new concepts and terminology, especially when a highly-specialized journal article uses terms different from those in the Study patent.  Since patent applicants are allowed to be their own lexicographers, the meaning of the technical terms used in the patent may either be broader or narrower than when they are used in NPL where an author’s use of the technical terms are usually based on the most-widely accepted meaning of the terms in the field.

In addition, certain types of information are more likely to be disclosed in a patent than in an NPL and vice-versa.   For example, the recitation of many steps in a process or method may be more likely to be found in patent literature than in NPL, especially when each step recited as part of the patented process is quite common or has been known for some time.  This is because journal articles devote most of the discussion on the new and unpublished properties or features of a device or material.  Thus, even the mere mention of a widely-known step in a process is often skipped since it is assumed that the readers of the article are already familiar with the basic concepts.

So, the question becomes should a Researcher just ignore these difficult-to-comprehend references?  And how can you tell if an NPL reference is relevant in the face of this complexity?  Here are a few tips for dealing with the challenges that come with NPL research:

  • Focus on the number of keywords found in the reference that match those mentioned in the Research Requirements section of the Study.  If the number of keywords that match is high (say, 4 out of 5 keywords), there is a good likelihood that the reference is relevant and can be uploaded as prior art.
  • Make sure that the matching keywords are found in the same paragraph, or at least in the same section of the reference.  This is called “Keyword Density.”  If the keywords are found in separate sections that represent different topics of a reference, it is likely that the keywords are not used to describe the same aspect of the invention.  If the keywords are not closely connected, the reference is less likely to be relevant.
  • If the reference has a low number of matching keywords, or a high number but low density, then you should still utilize the reference to help build your understanding of the technology.  The references may help to identify additional references.
  • In some cases, a reference may be too difficult to understand, and there are only one or two matching keywords.  Researchers should then look at the figures, flow charts, or diagrams to see if they look similar to those disclosed in the Study patent.  If the figures seem to match the invention claimed in the Study patent, it is important to identify whether there are any synonyms in the reference that are used in place of the keywords from the Study patent.  For example, this reference may use “cell phone” instead of “mobile phone,” meaning that you should expand your search terms to include “cell phone.”