Occasionally two or more applications are filed by different inventors
claiming substantially the same patentable invention. The patent can
only be granted to one of them, and a proceeding known as an
“interference” is instituted by the Office to determine who is the first
inventor and entitled to the patent. About one percent of the
applications filed become involved in an interference proceeding.
Interference proceedings may also be instituted between an application
and a patent already issued, provided the patent has not been issued for
more than one year prior to the filing of the conflicting application,
and provided that the conflicting application is not barred from being
patentable for some other reason.
Each party to such a proceeding must submit evidence of facts proving
when the invention was made. In view of the necessity of proving the
various facts and circumstances concerning the making of the invention
during an interference, inventors must be able to produce evidence to do
this. If no evidence is submitted a party is restricted to the date of
filing the application as his/her earliest date. The priority question
is determined by a board of three administrative patent judges on the
evidence submitted. From the decision of the Board of Patent Appeals and
Interferences, the losing party may appeal to the Court of Appeals for
the Federal Circuit or file a civil action against the winning party in
the appropriate United States district court.
The terms “conception of the invention” and “reduction to practice” are
encountered in connection with priority questions. Conception of the
invention refers to the completion of the devising of the means for
accomplishing the result. Reduction to practice refers to the actual
construction of the invention in physical form: in the case of a machine
it includes the actual building of the machine, in the case of an
article or composition it includes the actual making of the article or
composition, in the case of a process it includes the actual carrying
out of the steps of the process. Actual operation, demonstration, or
testing for the intended use is also usually necessary. The filing of a
regular application for patent completely disclosing the invention is
treated as equivalent to reduction to practice. The inventor who proves
to be the first to conceive the invention and the first to reduce it to
practice will be held to be the prior inventor, but more complicated
situations cannot be stated this simply.