What makes a claim indefinite under 35 U.S.C. 112(b)?

A claim can be considered indefinite under 35 U.S.C. 112(b) if it creates confusion about when direct infringement occurs. The MPEP 2173.05(p) provides an example from the In re Katz case:

“A single claim which claims both an apparatus and the method steps of using the apparatus is indefinite under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.”

For instance, a claim that includes both system elements and user actions can be indefinite because it’s unclear whether infringement occurs when the system is created or when a user performs certain actions. To avoid indefiniteness, claims should focus on the capabilities of the system rather than specific user actions.

To learn more:

• indefiniteness
• 35 U.S.C. 112(b)
• patent claims
• infringement