On many occasions and from many sources, including potential clients and patent attorneys, the phrase "stake in the ground" has been used to describe the purpose or goal of a provisional application. If one considers a provisional application to be a stake in the ground, to somehow capture an area of technology around a stake, all one will get is the stake. This is not a viable patenting strategy. The flaws of such strategy, previously significant for non-U.S. rights, now are magnified by virtue of the first to file provisions of the American Invents Act (AIA). The first-to-file provisions of the AIA will come into effect on March 16, 2013.
The viewpoint that a provisional application is somehow less than a regular application derives from a misunderstanding that the term "provisional" refers to the content of the application. "Provisional," however, does not refer to the content of the application, but refers to the rights created. The rights are provisional until perfected. Perfection is effected by filing a utility or international application and claiming priority to the provisional application.
The rights perfected, however, only pertain to claimed subject matter to the extent that such subject matter is disclosed in the provisional application in accord with the requisites of the U.S. patent laws, and for foreign rights, the requisites of a foreign jurisdiction. Hence the provisional application, to the extent possible, should include all subject matter and description required to provide a priority date for the scope of claims ultimately desired.
If a provisional application describes a single embodiment, there is a good chance that claims of any broader scope will not be awarded the priority date. This can have serious consequences.
Depending upon jurisdiction, any public disclosure of the subject matter of the provisional application or other embodiments, can render broader claims or claims to other embodiments per se unpatentable. Subject to certain exceptions, public disclosure, of the subject matter of the provisional or other embodiments, is prior art to claims that are not supported in the provisional application.
This includes generic claims and claims that encompass additional embodiments. Thus, disclosure of the subject matter of the provisional application, after it is filed, can defeat patentability of claims.
Hence, the viewpoint that a provisional application can be drafted with less care and less disclosure than a regular application, can lead to problems. These are not problems that one will only face in a potential litigation many years down the road, but they can arise during prosecution, preventing issuance of a patent with claims of sufficient scope, during an opposition leading a loss of claims in the patent, and during a due a diligence leading to a loss in value of the patent or application. The consequences of filing a provisional application that is limited or drafted with less care than a non-provisional application can be serious for the patentee.