Many Europeans are not familiar or comfortable with a particular type of patent document known as a “provisional patent application” (or “PPA” for short). The PPA is a type of application that exists only in the United States and India. This comment will focus on the US PPA, and will be the first of several blog entries that explain the use of the provisional patent application in US patent law.
What are the two kinds of US applications? All United States patents and patent applications are governed by Title 35 of the United States Code (“USC”). 35 USC §111 sets forth two kinds of US patent applications. §111(a) describes the requirements for an ordinary application, known as the “non-provisional application” (“NPA”), and §111(b) describes the requirements for a PPA.
How are the NPA and PPA similar? The NPA and the PPA are similar in at least three ways. First, they both require a written description of an invention (such description called a “specification”). Second, they both require at least one drawing “where required for the understanding of the subject matter” (which should be interpreted to mean, “one or more drawings are required in every patent application”). Third, as soon as either application has been filed, the applicant may claim to the world, orally or in writing, that the subject of the filed application has a “Patent Pending.”
How are the NPA and PPA different? The NPA and the PPA are different, however, in several fundamental respects:
(1) Duration: An NPA continues to live until it either issues as a patent or is clearly abandoned by the applicant. A PPA lives for exactly one year and not one day more – if, during that year, an NPA is filed that specifically relies upon the earlier PPA for a priority date, then the PPA continues to live as long as the NPA lives. But if a PPA is filed and no NPA is subsequently filed, the PPA automatically expires, without any action by the applicant, exactly one year after its date of filing.
(2) Effect: An NPA is not “a patent,” nor is a PPA a patent. However, the NPA could later become a patent after thorough examination by a US patent examiner, leading to a “Notice of Allowance” by the examiner. In contrast, the PPA may never at any time become a patent. The PPA may attach to the NPA that later becomes a patent, but the PPA cannot in its own right become patent.
(3) Examination by a Patent Examiner: An NPA will always receive a substantive examination by a US patent examiner (unless the applicant has explicitly withdrawn the application prior to review, which is very rare, although it does happen). An examination by an examiner is essential for the NPA to develop into an issued patent. A PPA, however, is never examined by a patent examiner. Such an examination is not required for a PPA, since the PPA never results in a patent.*
(4) Relationship to Patent Priority: An NPA may rely on one or more previously filed patent applications, stretching back in time without limit. Indeed there are some patent applications on basic technology that are followed by dozens of applications in later years, all such later applications relying through the chain of applications on the first application which is often called “the grandparent application.”** A PPA, however, may never rely on an earlier application for priority. The PPA must always be the first in a chain.
Further, an NPA may rely for its priority on two or more applications. For example, PPA1, PPA2, PPAx => NPA, means that the NPA takes priority from all three of the previously filed provisional applications, provided that the NPA was filed within one year of all the earlier filings. The PPA cannot rely on a prior application, so a fortiori the PPA cannot rely on two or more prior applications.
(5) Relationship to Claim Priority: Priority applies for specific patent claims, not for a patent in general. For example, in the simple chain PPA => NPA, the claims in the NPA all have the early priority date of the PPA, provided always that the PPA sufficiently supports the NPA.***
A different chain, such as PPA1, PPA2, PPAx => NPA, is much more complicated. The patent applicant of course wants the earliest possible priority for the claims in the NPA. Thus, the applicant wants the filing date of PPA1 as the priority date for all of the claims in the NPA. If PPA1 sufficiently supports all such claims, then the chain is really PPA1 => NPA, where PPA2, PPAx are irrelevant. However, in two cases that is not the result.
– First, some of the claims may not be discussed at all in an early application, so that they can only be supported in a later application, For example, PPA1, PPA2, PPAx => NPA when claims 1-5 of the NPA are supported in PPA1 and so have the early priority date of PPA1, claims 6-10 of the NPA are supported in PPA2 and so have the early priority date of PPA2, claims 11-20 of the NPA are not supported in any provisional application and therefore have the filing date of the NPA, and PPAx is irrelevant.
– Second, priority for a single claim in an NPA requires that every single claim element is sufficiently supported in the PPA. Sometimes, two or more PPAs are required to support a single claim. For example, PPA1 with claim elements  and  of claim #1 of the NPA, PPA2 with claim elements  and  of claim #1 of the NPA => NPA with claim #1 have four elements, and the priority date of claim #1 will be the filing date of PPA2 because PPA2 finishes support for claim #1.