The Patent Co-operation Treaty (PCT) is an international arrangement which provides a unified system for filing patent applications within any one its member countries. The international application is filed through the Receiving Office of a member country (eg. IP Australia), and establishes a filing date which is effective in each of the other member countries.
The international application may also claim priority from an earlier filed provisional application if filed within 12 months from the filing date of the provisional application. The application consists of a complete specification, the same as that of a complete application.
Once the international application is filed, an international patentability search is carried out by the Receiving Office for the invention and a written opinion is provided, which can be very useful to determine the chances of success for obtaining a valid patent in various member countries.
If relevant prior art is found, the international application can be amended within two months of the international search report or during optional international preliminary examination. The international examination procedure does not remove the requirement for examination of the national phase applications before the respective national Patent Offices. However, dealing with any patentability issues at an early stage can streamline the national examination process and reduce any associated costs.
The international application also provides a further 18 month period in which to manufacture and market an invention, and determine whether it is commercially viable.
After this 18 month period, the international application must be converted into one or more national or regional applications in each of the member countries where protection is sought. This is known as national phase and occurs 30 months (in most countries) from the earliest priority date, which is usually the filing date of an associated provisional application.
Once the application has entered national phase, the process is the same as that of a standard application, as you are effectively applying for a standard patent in each of the respective countries.