What is the best mode requirement under 35 U.S.C. 112(a)?

The best mode requirement under 35 U.S.C. 112(a) mandates that the inventor must disclose the best mode contemplated for carrying out the invention at the time of filing the patent application.

MPEP 2166 provides a form paragraph for best mode rejections:

“Claim [1] rejected under 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph, because the best mode contemplated by the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), has not been disclosed. Evidence of concealment of the best mode is based upon [2].”

The MPEP notes that “Use of this form paragraph should be rare. See MPEP §§ 2165 – 2165.04.” This indicates that best mode rejections are not common and should be made only when there is clear evidence of concealment.

It’s important to note that while the best mode must be disclosed if known, there is no requirement to update the best mode if a better mode is discovered after filing the application.

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Topics: First Paragraph, MPEP 2100 - Patentability, MPEP 2166 - Rejections Under 35 U.S.C. 112(A) Or Pre - Aia 35 U.S.C. 112, Patent Law, Patent Procedure
Tags: 35 u.s.c. 112(a), Best Mode, Concealment, Patent Specification