What is a classic example of a field of use limitation?

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.

A classic example of a field of use limitation comes from the case Parker v. Flook, as cited in MPEP 2106.05(h). In this case, the claim recited steps for calculating an updated alarm limit value using a mathematical formula in the context of “a process comprising the catalytic chemical conversion of hydrocarbons.”

The Supreme Court found that limiting the use of the formula to the petrochemical and oil-refining fields was not sufficient to make the claim eligible. The MPEP explains:

“Although the applicant argued that limiting the use of the formula to the petrochemical and oil-refining fields should make the claim eligible because this limitation ensured that the claim did not preempt all uses of the formula, the Supreme Court disagreed.”

The Court reasoned that this limitation was merely an incidental or token addition to the claim that did not alter or affect how the process steps of calculating the alarm limit value were performed. It did not amount to an inventive concept or integrate the abstract idea into a practical application.