This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.
The Milburn rule, codified in pre-AIA 35 U.S.C. 102(e), allows the use of a U.S. patent as a reference against a later filed application as of the U.S. patent filing date. The MPEP explains this in MPEP 2136.04:
“As stated by the House and Senate reports on the bills enacting section pre-AIA 35 U.S.C. 102(e) as part of the 1952 Patent Act, this subsection of 102 codifies the Milburn rule of Milburn v. Davis-Bournonville, 270 U.S. 390, 1926 C.D. 303, 344 O.G. 817 (1926).”
This rule is significant because it establishes that an earlier filed U.S. application containing the subject matter claimed in a later application indicates that the applicant of the later application was not the first inventor.