What Is a Terminal Disclaimer?

Introduction

In patent law, a terminal disclaimer is a legal document filed with the USPTO to limit the enforceable term of a patent. This article explains the purpose of terminal disclaimers, when they are used, and their implications for patent holders. Spoiler: Now that US patent terms are 20 years from initial filing rather than 17 years from patent issuance, they are not nearly as big a deal.

Purpose of Terminal Disclaimer

The primary purpose of a terminal disclaimer is to address double patenting issues. Double patenting occurs when an applicant seeks multiple patents for the same invention, potentially extending monopoly rights beyond what is intended by patent law. This was a huge problem when patent terms were 17 years from the date the patent issued — and terminal disclaimers are somewhat vestigial leftover from that era (although they do limit patent terms in some cases).

When Is a Terminal Disclaimer Used?

Terminal disclaimers are typically used in the following scenarios:

• Obviousness-Type Double Patenting (ODP): When two patents or patent applications contain claims that are not patentably distinct from each other.
• Unity of Invention: Ensuring that claims in related applications do not overlap excessively.

Implications of Terminal Disclaimer

By filing a terminal disclaimer, patent holders:

• Limit the enforceable term of the patent to be co-terminous with another related patent.
• Prevent the assertion of rights beyond the expiration date of the related patent.
• Maintain compliance with USPTO rules and regulations on double patenting.

Conclusion

Terminal disclaimers play a critical role in patent prosecution, ensuring compliance with patent law principles and preventing the extension of patent rights beyond their intended scope. Patent holders should carefully consider their use in managing patent portfolios and addressing double patenting rejections.