In 1994, Congress passed an amendment to the Patent Act which permitted the filing of a “provisional” patent application in the US Patent and Trademark Office (USPTO).  Provisional patent applications are touted as being a fast, cheap and easy way to achieve “patent pending” status for up to a year before a follow-up, “nonprovisional” patent application must be filed with the USPTO.  But these applications must be used with care by the applicant if its entitlement to a valid patent is not to be irreversibly destroyed.

The provisional patent application has to have a specification and must name the inventor(s) of the invention.  If the subject matter admits to illustration (as all but chemical inventions will), it must be accompanied by drawings.  But a provisional patent application does not have to have many other requirements of a nonprovisional patent application:  it doesn’t have to include a background of the invention, a summary of the invention, a brief description of the drawings, claims, or an abstract of the disclosure.  It further does not need an Inventor’s Oath or Declaration and the USPTO charges far less for filing it than it does for the filing of a nonprovisional patent application.

A provisional patent application, by itself, will never mature into a patent.  All it does is give the applicant a filing date – which, under certain circumstances, may be used by the applicant as a priority date to determine the contents of the prior art with respect to its later, nonprovisional patent application and patent.  Those circumstances include (a) a nonprovisional patent application must be filed in the USPTO no later than the anniversary of the filing date of the provisional patent application; (b) the claims of the nonprovisional patent application must find complete support in the technical disclosure of the provisional patent application; and (c) the claimed subject matter must have been adequately illustrated by the drawings filed with the provisional patent application.

One sometimes sees recommendations, by technical writers and columnists who ought to know better, to file a sketchy disclosure as a provisional patent application – and then to file a more complete disclosure as a portion of the nonprovisional patent application.  This is worse than useless.  It often happens that the claims of the follow-on nonprovisional patent application cannot find adequate support in the provisional application specification.  In this instance, the effective filing date of those claims is not the filing date of the provisional patent application – it is the filing date of the nonprovisional patent application, which very often is about a year later.  Prior art references having publication dates after the provisional patent application filing date, but before the nonprovisional application filing date, then may be applied to the claims.  Even worse, the public activities of the applicant – such as exhibiting the invention at a trade show – that occurred more than one year prior to the nonprovisional patent application filing date may render the claimed invention unpatentable.  This may happen, for example, where the applicant waited a year from its first public disclosure to put a provisional patent application on file, and then waited another year before putting a nonprovisional patent application with augmented disclosure on file.

The same thing would happen if the provisional application is filed with drawings that are so inadequate that a court later determines that a person of ordinary skill in the art was left with insufficient guidance on how to make and use the invention.

Further, adding more disclosure (or drawings) to the nonprovisional patent application puts the applicant into an evidentiary trick bag.  An opponent (typically: an accused infringer) will ask, why was that augmentation necessary?  The opponent may contend that applicant’s augmentation of the disclosure, and/or of the drawings, counts as an admission by the applicant that the initial provisional application disclosure was inadequate.

Another issue is: on what invention was the provisional patent application filed?  The scope of an invention is determined by the claims, which are numbered paragraphs appearing at the end of the specification of a nonprovisional patent application.  Provisional patent applications don’t need any.  But if no claims are written, there is a danger that claims, only written later as a portion of the nonprovisional patent application, won’t find support in the provisional application disclosure.  Since the provisional application writer didn’t know what the claims would say at the time he wrote the provisional patent application specification, he may have only a hazy or incomplete idea of what needs to be disclosed to support those future claims.  Many times, and to solve this problem, patent attorneys will write some claims anyway, and make sure that the provisional disclosure supports them – just to make sure that a fuller, later claim set is more likely to find support in the provisional specification. But writing such claims erodes both of the provisional patent application’s principal advantages, which are lower cost and less preparation time.

There is also an effect on when any foreign patent applications should be filed.  Under the Paris Convention, and in order to enjoy the US filing date, a US applicant has up to one year to file any foreign patent application that corresponds to its US utility patent application.  The US patent application that is used is the one that first discloses the claimed subject matter.  Where a provisional patent application had been filed, the US applicant has up to one year from the provisional application filing date to file any foreign patent application.  The one year grace period created by the provisional patent application, and the one-year grace period created by the Paris Convention, do not “tack”; they cannot be added together.  They run at the same time.  The provisional applicant thus has to decide whether and if it wants any foreign patent protection at the same time that it is deciding whether to continue to pursue patent protection in the US.

Finally:  if a patent attorney is to be retained to write and file the provisional patent application, “transmission slip” will occur.  A year later, the patent attorney will have to refamiliarize himself with the subject matter in order to write the nonprovisional patent application.  Overall, the use of a provisional patent application, in a process leading to the issue of a US patent, is less cost- and time-efficient than just filing a nonprovisional patent application in the first place.

Preparing and filing a provisional patent application might make sense in limited circumstances.  There may be not enough time to do a nonprovisional patent application before the anniversary of the first public disclosure of the invention, or (where foreign patent protection is wanted) the impending date of first public disclosure itself.  The applicant may be under such extreme economic pressure that is can’t afford the additional cost of getting a nonprovisional patent application prepared and filed.  But absent these extenuating circumstances, the use of provisional patent applications should be avoided.