Provisional applications allow an inventor to get a patent application on file and secure a filing date.  They are not examined by the patent office and do not issue into patents.  Rather, at the end of one year, they expire.  However, prior to expiration, the provisional application can be “converted” into a non-provisional application which claims priority to the provisional application filing date.  In this way, a provisional application can be used to obtain an early filing date even if an inventor is not ready to file a non-provisional application.

Provisional applications are particularly useful when an invention is still being developed.    A provisional application can be modified when it is converted to a non-provisional application, and new material can be added to it.  However, once the non-provisional application is filed, nothing new can be added to it.  If it seems like meaningful modifications or additions to the invention might occur over the next year, it may make sense to file a provisional application first to get an earlier filing date for the original ideas, and then incorporate any changes or additions into an updated provisional application or when it the provisional application is converted to a non-provisional application.

Non-provisional applications, sometimes referred to as utility applications, are complete applications that are examined by the patent office and can issue into patents.  They are usually many pages long, ending in a numbered list of claims which specify the invention that is protected by the patent. Once a non-provisional application is filed, no substantive changes can be made to it, although the claims can be revised during prosecution so long as the changes do not add anything new to the application.

Design patents protect original ornamental designs, or how something looks, rather than what it does or how it does it.  Since design patents protect the visual appearance of an invention, they include a series of figures and very little description.   Design patents are often quicker and easier to obtain than non-provisional patents but their scope of protection is narrower.  For some inventions it is possible to obtain both a design patent and a non-provisional patent.

U.S. patents do not prevent others from copying your invention outside of the US.  Patent protection for U.S. inventions can be achieved outside the U.S. through the use of a PCT application or through direct filed foreign applications.  However, adding international patent protection significantly increases the cost of protecting an invention, so it is not appropriate in all cases.

P.C.T. stands for Patent Cooperation Treaty and it is a mechanism to allow a single patent application to be entered into most countries around the world at a later date and for additional fees in a process called national stage entry.  The P.C.T. is an expensive but useful tool when an owner of an invention wants to file in multiple countries.

Another option is to file a patent application directly in those foreign countries in which patent protection is desired.  When patent protection outside the U.S. is important but is only needed in perhaps one or two countries, this may be more cost effective than proceeding through a P.C.T. application.