The "first to file" system became the world wide priority

 

President Barack Obama signs the America Invents Act, Friday September 16, 2011, at Thomas Jefferson High School for Science and Technology in Alexandria, VA

 

First to file and first to invent are legal concepts that define who has the right to the grant of a patent for an invention. The first-to-file system is used in all countries except for the United States, which operates a first-to-invent system until the America Invents Act of 2011 is enacted into law by President Obama. (see more info here)

In a first-to-file system, also called "first inventor to file" system, the right to the grant of a patent for a given invention lies with the first person (the first inventor(s)) to file a patent application for protection of that invention, regardless of the date of actual invention.

The United States is unique in using a first-to-invent system. Canada and the Philippines had similar, although slightly different, systems until 1989 and 1998, respectively. Invention in the U.S. is generally defined to comprise two steps: (1) conception of the invention and (2) reduction to practice of the invention. When an inventor conceives of an invention and diligently reduces the invention to practice (by filing a patent application, by practicing the invention, etc.), the inventor's date of invention will be the date of conception. Thus, provided an inventor is diligent in actually reducing an application to practice, he or she will be the first inventor and the inventor entitled to a patent, even if another files a patent application, constructively reducing the invention to practice, before the inventor.

However, the first applicant to file has the prima facie right to the grant of a patent. Should a second patent application be filed for the same invention, the second applicant can institute interference proceedings to determine who was the first inventor (as discussed in the preceding paragraph) and thereby who is entitled to the grant of a patent. Interference can be an expensive and time-consuming process.