The United States has a form of patent application called a Provisional Patent Application. Some people feel that these are an easy and inexpensive way to obtain a filing date and some patent rights, but they are usually unaware of the risks and downside.
These patent applications never issue into a patent, and can never be enforced to prevent someone from copying your invention. If a regular, complete, patent application is prepared and filed within a year from the filing date of the provisional patent application, the regular patent application may be entitled to the filing date of the provisional patent application, but only if the provisional application meets best mode and enablement requirements.
In order to be valid, the provisional application must comply with the first paragraph of section 112 of the patent law. If the provisional application does not comply with this section, it will be invalid and will not provide a filing date. As the U.S. Patent and Trademark Office does not examine these applications, it may not become apparent that a provisional application is invalid until after the deadline for filing a patent application has passed. It should also be kept in mind that provisional applications automatically expire one year after filing, and that this deadline is not extendible. Foreign applications must be filed within one year of the filing date of the provisional application in order to be entitled to the filing date of the provisional application. Thus, a disadvantage of provisional applications is that there is no opportunity to receive a first examination by the U.S. Patent and Trademark Office before making the decision of whether or not to file corresponding foreign applications.
If provisional applications are used, it is recommended that they be drafted as if they were a full regular patent application to make sure that they comply with the best mode and enablement requirements. An invalid patent application has zero value. A patent infringement trial typically costs over a million dollars in legal fees and it is not wise to skimp on fees during the patent drafting process. With such high stakes, a professional litigator is looking for every weakness in a patent application. A provisional application that is not drafted by a patent attorney is likely to have many problems. These problems will carry through even if a patent attorney is later hired to draft a regular patent application. This is because the "file history" of the patent application will be ordered and the provisional patent application will be available along with the file history.
An example of a case where a provisional patent application failed to provide a useful filing date is New Railhead* Mfg., L.L.C. *v*. *Vermeer* Mfg. Co., 298 F.3d 1290, 1294,. 63 USPQ2d 1843, 1846 (Fed. Cir. 2002). The issued non-provisional patent was found to be invalid because a feature was not properly disclosed in the earlier provisional patent application.
For example, if an applicant in a provisional application says "the switch is a MOSFET" where no specific type is essential, and then a patent attorney preparing a regular patent application corrects this by saying "there is a switch, it can be any type but in some embodiments it is a MOSFET", be prepared for an argument during litigation that unless a competitor uses a MOSFET, there is no infringement regardless of what is recited in the claims because the inventor clearly only contemplated use of a MOSFET.
If there is no budget for a full application and a provisional application is filed, a full application drafted by a patent attorney should be filed as soon as possible after the provisional application is filed. Thus, in the event that the provisional application does not comply with the provisions of 35 U.S.C. 112, first paragraph, it may be possible to prepare the regular application before any important deadlines are missed.
It should be kept in mind that it usually takes three or more months for a patent attorney to prepare an actual U.S. patent application, depending on workload. Therefore, if you file your own provisional patent applications, do not wait until the end of the one year period to decide if you want to proceed with a regular patent application. Because of varying caseload demands and other concerns, law firms usually reserve the right to refuse to accept work for any reason. Also keep in mind that the provisional applications automatically expire one year after they are filed. No one will remind you of the deadline for filing an actual patent application. No extensions of time are available.
With these risks in mind, provisional patent applications that are not drafted as full regular patent applications can still be useful for obtaining "patent pending" status if there is simply no budget for a full patent application.