What is the legal standard for obviousness of overlapping ranges?

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.

According to MPEP 2144.05, “In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.” This principle is based on several court decisions, including In re Wertheim and In re Woodruff.

The MPEP further states: “[A] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness.” This means that even if the claimed range is narrower than the prior art range, it may still be considered obvious if it falls within the broader prior art range.