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.
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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.