What is the significance of functional language in patent claims?

Functional language in patent claims describes an element in terms of what it does rather than what it is. The MPEP provides guidance on interpreting such language:

“Functional claim language may be given patentable weight if it is determined that the prior art structure does not inherently possess the functionally defined limitations of the claim.”

This means that functional language can be used to distinguish a claim from prior art. However, it’s important to note:

• Functional language must still meet the requirements of clarity and definiteness under 35 U.S.C. 112(b).
• If the function is performed by a well-known structure or technique, the claim may still be anticipated by prior art.

The MPEP further states:

“When a claim limitation employs functional language, the examiner’s determination of whether the limitation is sufficiently definite will be highly dependent on context.”

This emphasizes the importance of considering the entire patent specification and the knowledge of a person of ordinary skill in the art when interpreting functional claim language.

To learn more:

• functional language
• claim interpretation
• patent claims
• claim limitations