What is a terminal disclaimer?
Think of a terminal disclaimer as a limit on the term of a patent. This mechanism is used by the USPTO to facilitate fairness. Patent owners should not gain an unfair advantage by filing new patents which would extend their exclusive rights beyond the lifetime of a related patent.
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When will a patent expire?
The general rule is that utility patents expire 20 years from the filing date of the earliest nonprovisional application in the patent family. Notice that a provisional patent application does not reduce the term of a utility patent.
A patent term adjustment (PTA) will extend the term of a patent by a specified number of days. Issued patents typically include a PTA notice on the face page of the patent certificate.
Keep in mind that a utility patent can expire prematurely if maintenance fees are not timely paid.
Obviousness Double Patenting Rejection: When to File a Terminal Disclaimer
Occasionally, an examiner may reject a patent application on the grounds of obviousness double patenting. This is a rejection based not on prior art, but on a related patent by the same applicant. In other words, the applicant is seeking two or more patents on highly similar inventions. Claims in one patent may appear quite similar to claims in the application where the obviousness double patenting rejection was issued.
To overcome an obviousness double patenting rejection, a terminal disclaimer is filed so that the pending application will not lead to patent rights that would unfairly lengthen the term of a new patent.
Terminal Disclaimer Vocabulary
Let’s define a couple of legalese terms that we’ll use throughout this article. We’ll call the patent application in which a disclaimer is filed the Subject Patent. The other patent filing referenced in the disclaimer will be called the Reference Patent.
Terminal Disclaimer in a Subject Patent without PTA
Suppose you file a terminal disclaimer in an application that ultimately issues without a PTA. In that case, the term of the Subject Patent will simply be 20 years from the earliest nonprovisional filing date in the patent family.
If the Reference Patent is not a parent of the Subject Patent, then the term of the Subject Patent will be the term of the Reference Patent excluding any PTA in the Reference Patent.
What if Reference Patent has a PTA, but Subject Patent does not?
If the Reference Patent has a patent term adjustment, but the Subject Patent does not, the expiration of the Subject Patent will be the normal expiration of the Reference Patent without counting its PTA.
What if Reference Patent has a PTA and Subject Patent has a lower PTA?
Suppose the Reference Patent has a PTA of 300 days and the Subject Patent has a PTA of 50 days. The expiration of the Subject Patent will be the normal expiration of the Reference Patent plus 50 days.
What if Reference Patent has a PTA and Subject Patent has a higher PTA?
Suppose the Reference Patent has a PTA of 300 days and the Subject Patent has a PTA of 350 days. The expiration of the Subject Patent will be the normal expiration of the Reference Patent plus 300 days. In other words, use the lower PTA of the Reference Patent when the Subject Patent has a higher PTA.
What if Reference Patent has no PTA, but Subject Patent does?
Suppose the Reference Patent has no PTA, but the Subject Patent has a PTA of 100 days. In this situation, the PTA of the Subject Patent will not provide any extended term. The Subject Patent will expire on the normal expiration of the Reference Patent.
