One of the trickiest aspects of patent applications, particularly in the international context, is establishing the priority of patent rights. Rules applying to priority differ starkly between the United States and many foreign countries. The United States has a “first-to-invent” rule, which means that an inventor that can establish that he or she was the first to conceive of and create an invention will be given priority over another inventor of the same invention even if the second inventor applies for a patent first. In contrast, many foreign countries have a “first-to-file” rule, which means that the first inventor to apply for a patent will be given priority even if another inventor actually conceived of and created the same invention first. Further complicating the issue of priority is the fact that, in the United States, an inventor may publicly disclose an unpatented invention and will have a year to file for a patent. In many foreign countries, any public disclosure of an invention renders it ineligible for a patent. Thus, a U.S. inventor might be able to obtain a U.S. patent but be ineligible for patent protection in other countries even though U.S. patent rules were correctly followed.
One benefit of the Paris Convention was the establishment of a right of priority. If a U.S. inventor files an application for a patent for an invention not previously disclosed to the public, foreign patent applications may be filed within one year in any country that is a party to the Paris Convention, and the U.S. filing date will serve as the filing date of the foreign applications as well. Under the Paris Convention then, once the U.S. patent application is filed, the invention may be publicly disclosed or even sold without rendering it ineligible for foreign patent protection.
Another treaty affecting patent priority is the Patent Cooperation Treaty (PCT), under which an international “patent application” may be filed. The PCT patent application does not result in the issuance of a patent but rather establishes a filing date for patent applications in those countries that are members of the PCT. The PCT international patent application may be filed within one year of filing for a patent in the United States or any of the other PCT-member countries, and additional patent applications in other PCT-member countries may be filed within 18 months of the PCT international patent application. The primary advantage of the PCT international patent application is that the patent applicant establishes the date of filing for priority purposes without the large financial commitment required to file regular patent applications in several foreign countries. In addition, the inventor gains time in which to assess the viability of the invention and whether it will be beneficial to seek patent protection in foreign countries, as it is altogether possible that some information will come to light that reveals that the expense of pursuing certain foreign patents will provide insufficient return on the investment to make the foreign patents worthwhile.