What are negative limitations in patent claims?

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.

Negative limitations in patent claims are statements that describe what the invention is not, rather than what it is. According to MPEP 2173.05(i), “The current view of the courts is that there is nothing inherently ambiguous or uncertain about a negative limitation. So long as the boundaries of the patent protection sought are set forth definitely, albeit negatively, the claim complies with the requirements of 35 U.S.C. 112(b).”

Negative limitations can be used to exclude certain elements or characteristics from the claimed invention, helping to define its scope more precisely.