General Rule: U.S. Patent Applications Are Published After 18-Months
Unless a patent applicant files a non-publication request, U.S. patent applications are automatically published after 18-months from their earliest priority date. See MPEP 1120 Eighteen Month Publication of Patent Applications. Hence, after a U.S. patent application is filed, it is published by the U.S. Patent Office for the public to view even if it hasn't been granted as a patent yet. Published patent applications can also be searched on the U.S. Patent Office website.
Provisional Patent Applications Are Not Published
Provisional patent applications are not published since they are not examined and they are only pending at the U.S. Patent Office for 12-months. After 12-months, a provisional patent application automatically becomes abandoned and therefore will never be published. Only a non-provisional patent application can be published by the U.S. Patent Office. Hence, a provisional patent application will remain secret at the U.S. Patent Office with a few exceptions discussed below.
Exceptions to Provisional Patent Application Secrecy
While a provisional patent application is never published by the U.S. Patent Office for the public to view or search, there are two situations when a provisional patent application will be made publicly available for inspection. If a non-provisional patent application is filed claiming priority to the provisional patent application and the non-provisional patent application is either (i) published or (ii) granted as a patent, then the public may download a copy of the provisional patent application via Public PAIR or request a copy of the provisional patent application. It is important to note that this is not publication of the provisional patent application and the provisional patent application cannot be publicly searched - the only access is provided by Public PAIR or a direct request from the public to inspect the provisional at the U.S. Patent Office.