What is the difference between a negative limitation and a disclaimer in patent claims?

What is the difference between a negative limitation and a disclaimer in patent claims?

While both negative limitations and disclaimers involve excluding certain elements or features from patent claims, they have distinct characteristics and purposes:

Negative Limitations:

• Are part of the original claim language
• Explicitly state what is not included in the claimed invention
• Must have support in the original disclosure
• Example: “A composition free of copper”

Disclaimers:

• Are typically added after the original filing
• Used to overcome prior art rejections or avoid double patenting
• Can sometimes introduce limitations not originally disclosed
• Example: “A disclaimer of the portion of the term of a patent that extends beyond the expiration date of another patent”

The MPEP 2173.05(i) focuses primarily on negative limitations, stating:

“The mere absence of a positive recitation is not a basis for an exclusion. Any negative limitation or exclusionary proviso must have basis in the original disclosure.”

This emphasizes that negative limitations must be supported by the original disclosure, while disclaimers may sometimes introduce new limitations to overcome specific issues during prosecution.

To learn more:

• negative limitations
• disclaimers
• patent claims
• exclusionary proviso