Can experimental use negate the on-sale bar in patent law?

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.

Experimental use can potentially negate the on-sale bar in patent law. According to MPEP 2133.03(b):

“If the use or sale was experimental, there is no bar under 35 U.S.C. 102(b).”

Key points about experimental use:

• It must be for the purpose of perfecting the invention, not for commercial exploitation.
• The inventor must maintain control over the experimentation.
• The experimentation must be necessary to bring the invention to perfection.
• Detailed records of the experimentation should be kept.

Courts consider various factors to determine if a use or sale was truly experimental, including the length of the test period, whether payment was made, and whether there was a secrecy agreement.