What is the critical period for showing diligence in patent applications?

The critical period for showing diligence in patent applications is defined in the MPEP as follows: Under 37 CFR 1.131(a), the critical period in which diligence must be shown begins just prior to the effective date of the reference or activity and ends with the date of a reduction to practice, either actual or constructive (i.e., filing a United States patent application).

This means that an inventor must demonstrate continuous effort from just before the date of the prior art reference or activity that is being overcome, up until the invention is reduced to practice. It’s important to note that only diligence before reduction to practice is a material consideration. Any lack of diligence after the actual reduction to practice but before filing the patent application is not relevant for the purposes of a 37 CFR 1.131(a) affidavit or declaration.

To learn more:

• diligence
• critical period
• patent application
• reduction to practice
• 37 CFR 1.131(a)

To learn more:

• 37 CFR 1.131(a)