[For assistance with the preparation and filing of a provisional patent application, see Nolo’s Online Provisional Patent Application.]
In 1995, a system went into effect that permits an inventor to file a Provisional Patent Application (PPA), an interim document that is equivalent to a “reduction to practice.” An inventor who has not completed a patent application but wants to establish a filing date can file a Provisional Patent Application (PPA). If a regular patent application is filed within one year of filing the PPA, the inventor can use the PPA’s filing date for the purpose of deciding whether a reference is prior-art. (Note: the PPA is not available for design patents.)
The PPA must contain a description of the invention and drawings (if necessary to understand the description). The description of the invention must clearly explain how to make and use the invention. If there are several versions or modes of operation for the invention, the best mode or version must be disclosed. If the inventor wishes, claims, formal drawings and other elements of the regular patent application may be included.
The advantages of the PPA are that it costs far less than filing a patent application (usually several hundred dollars compared to several thousand dollars), doesn’t require witnesses, saves the expense of building and testing and the application is much simpler to complete. In addition to an early filing date and the right to claim patent pending status for an invention, filing a PPA can provide an additional advantage. Since the filing date of the PPA has no effect on the patent's expiration date, the patent's expiration date will still be 20 years from the date the regular patent application is filed. So a PPA has the practical effect of delaying examination of a regular patent application and extending--up to one year--the patent's expiration date. However, the same delaying effect can be obtained if an inventor builds and tests the invention and makes a signed, dated, and witnessed record and delays filing for a year.
The disadvantages of the PPA are that if the inventor doesn’t file a regular patent application within a year of the PPA, the PPA is abandoned and will no longer provide a filing date for purposes of prior-art or interferences. The PPA is worthless if the inventor changes the invention so that it is not longer as described. The filing of a PPA also affects an inventor’s foreign rights. As with a regular U.S. application, an inventor must pursue foreign patent applications within one year of the PPA's filing date (in order to obtain the advantage of the filing date).