There are four types of U.S. national applications: a PCT national stage application, a regular domestic national application, a provisional application, and an international design application under the Hague Agreement.

A PCT “International” Phase Application needs to be completed with 12 months from the priority date which is the filing date of a parent application. A PCT U.S. “National” Phase Application needs to be completed within 30 months from the priority date so as to enjoy an effective filing date in the United States as of the filing date of the parent application that will be an application filed in a county other than the U.S. Please beware that a patent law is national and there is no “international” patent. A PCT “International” Phase Application is to conveniently, collectively reserve a right to file a “national” phase application under the Patent Cooperation Treaty (PCT) within 30 months from the priority date.

If an applicant has missed filing a PCT U.S. national application with 30 months from the priority date, the applicant can still file a PCT U.S. national stage application together a petition to revive an unintentionally abandoned application. The U.S. Patent Law technically translates the date of the PCT “International” Phase Application as a U.S. filing date if the U.S. was designated (the designation is now automatic) at the international phase, so missing the filing due date remains equivalent to abandonment of an application resulting from missing a final due date of like an office action in a regular patent application.

The PCT national stage application is unique compared to a domestic national application in that:

• it is submitted later (i.e., normally 30 months from a claimed priority date as compared to 12 months for a domestic application claiming priority); and
• the status of the prior art is generally known before the national stage begins and this is not necessarily so in a domestic national application.