How does the MPEP address negative limitations in patent claims?
The MPEP addresses negative limitations in patent claims in MPEP 2173.05(i), which is closely related to the discussion on alternative limitations in MPEP 2173.05(h). The MPEP states:
“The current view of the courts is that there is nothing inherently ambiguous or uncertain about a negative limitation.”
This guidance indicates that negative limitations are generally acceptable in patent claims, provided they meet other requirements for clarity and definiteness. Negative limitations can be used to exclude certain elements or steps from the claimed invention. However, the MPEP also cautions:
“Any negative limitation or exclusionary proviso must have basis in the original disclosure.”
This means that while negative limitations are allowed, they must be supported by the original specification to avoid issues under 35 U.S.C. 112(a). When drafting claims with negative limitations, it’s important to ensure they are clear, definite, and have proper support in the original disclosure.
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