Is Your Invention Patentable over the Prior Art?

There are two distinct requirements concerning patentability over prior work in the field (known as “prior art”): novelty, and non-obviousness.  An invention does not meet the novelty requirement if at the time of filing it was “anticipated” by prior art, meaning that every element is found, expressly or inherently, in a single prior art reference.1  For example, suppose that your invention is white LED headlights for a vehicle, and a patent pre-dating your patent application included an illustration of a car with very small headlights but did not expressly describe that they were white or LED.  If a person having ordinary skill in the relevant field of work would have understood that headlights of the depicted size and shape would have to be LED and that headlights need to be white, then those elements are inherently found in the patent reference and your invention is anticipated.

The non-obviousness requirement is more difficult to meet.  An invention does not meet that requirement if, though not anticipated, its differences over the prior art would have been obvious to implement.2  A patent examiner or challenger alleging obviousness typically combines features described in one reference with features described in another reference.  For example, suppose that your invention is LED headlights for a vehicle, and a patent pre-dating your patent application depicted a car with halogen headlights.  If one of ordinary skill in the art would have thought it straightforward to substitute LED lights in their place, then your invention is obvious in light of the patent combined with any suitable reference disclosing LED lights.

To be applicable as prior art in the first place, a reference must be prior to your patent application.  Since the United States is now a “first-to-file” system, roughly speaking,3 a reference is deemed to be prior if its relevant date precedes your application’s effective filing date.4  The relevant date of a reference depends on what kind of reference it is.

For literature and foreign patents and published patent applications, the relevant date is the date of publication.  For example, if you file a patent application describing an invention in March, but an article was published in February disclosing the invention, the article is prior art to your application’s claims to the invention.  If the article was published in April, it would not be prior art, even if it was submitted to the publisher in February.

For U.S. patents and published applications and published PCT5 applications, the relevant date is the effective filing date.6  For example, if you file a patent application first describing an invention in March but someone else filed a U.S. patent application disclosing the same invention in February, and that person’s application later published or issued as a patent, it would be prior art to your application’s claims.7  If the other person’s application were abandoned before being published or issued, however, it would not be prior art to your application’s claims.

The relevant date (and actual qualification as prior art) can be harder to ascertain for things like trade show exhibits, websites, public displays, and sales, but is generally the earliest date of public disclosure.  The United States has a one-year “grace period,” however, so sales or disclosures made by the inventor (or someone who derived the invention from the inventor) do not count as prior art to an application filed within one year of the earliest such sale or disclosure.  You should obtain advice from a skilled patent attorney before making any pre-filing disclosure, because the law on this topic can be quite tricky.  Also, most other countries have no such grace period, so pre-filing sales or public disclosures should not be made (anywhere) if you are interested in protecting your invention outside the U.S.

  1. See 35 U.S.C. §102.
  2. See 35 U.S.C. §103.
  3. There is a grace period in some situations, however, and the statute defining prior art (35 U.S.C. §102) is complicated.  You should consult a skilled patent attorney to determine whether a specific reference or act is or would be prior art against an existing or potential patent claim.
  4. The effective filing date is the date of filing of the earliest application to which the application at issue is entitled priority, as long as that earliest application described the subject matter of the patent application’s claims at issue.  For example, if Application 1 disclosed A and was filed in January, and Application 2 disclosed A+B and was filed in June with priority to application 1, prior art disclosing A+B made public in March would not be prior art against Application 2’s claims to A but would be prior art against its claims to A+B.  This is because the subject matter B was not included in an application until after the prior art arose.
  5. PCT stands for Patent Cooperation Treaty, which is a route for filing patent applications internationally.  Multiple countries can be designated in such applications; a PCT application must include a designation of the U.S. in order for its filing date to be its date as prior art.  The “Patent Protection Outside the U.S.” Primer discusses this further.
  6. The relevant filing date here is the earliest filing date of an application describing the claimed subject matter, to which the patent or published application is entitled.
  7. The prior art in this scenario is sometimes called “secret prior art” because it is not publicly available at the time of your application.