A claim of priority gives you the right to claim the benefit of an earlier filing date for your patent application. In this manner, your patent application would have the earliest priority date possible. Prior art that predates the filing date of your patent application would not be prior art.
What’s the benefit of a claim of priority?
As stated above, you can eliminate prior that predates your patent application. A typical example is when you file a nonprovisional application that claims priority back to an earlier filed provisional application. Any prior art dated between the filing dates of the provisional and nonprovisional applications is not considered prior art to your nonprovisional application. Your nonprovisional application is treated as if it was filed on the filing date of the provisional application.
This is the very reason that you can have confidence in marketing your product after filing a provisional application. No one else can see your marketing efforts and file their own application to steal your idea. With the claim of priority back to the provisional application, you have priority (i.e., first in line) over the other person’s later filed patent application.
Additionally, any type of marketing by the other person would not be considered prior art against your nonprovisional application. Once again, you have an earlier priority date due to the claim of priority.
How to build a patent portfolio by claiming priority to an earlier filed application?
The ability to claim priority to an earlier filed patent application gives you the ability to develop a patent portfolio around your product. After you file your first application and get your first patent, you can file a continuation or divisional application which claims priority back to your first application. The continuation or divisional application could seek broader patent claims compared to the claims in your first patent.
You might think that the claims of your first patent are the broadest claim that the examiner might allow. However, that is not the case. Oftentimes, the broadest claim is not obtained in the first patient. In my experience, the broadest claims for an invention oftentimes come after filing one or more continuation applications.
You can file multiple continuation and divisional applications one after the other to continue to mine your original patent application. These applications would seek to protect multiple aspects of your invention. You are not limited to seeking a patent for your invention in only one aspect. You can read more about developing a patent portfolio by filing a continuation application here.
How do you claim priority to an earlier filed patent application?
To claim priority to an earlier filed patent application, the earlier filed patent application has to be pending when you file the later filed patent application. This is referred to as the co-pendency requirement. You cannot allow the earlier filed application to go abandoned. If so, you can no longer claim priority to that application.
Also, when you have a notice of allowance and are ready to pay the issue fee, you need to decide whether you will file a continuation or divisional application before you pay the issue fee. Once the patent is granted, the application is no longer pending and you cannot file a continuation application.
Next, you need to make a specific reference to the earlier filed patent application in an Application Data Sheet (ADS) filed with the later filed patent application. Preferably, the claim of priority is made when the layer of application is filed but the claim can be made up to four months later, or even after that with the payment of a hefty surcharge.