The Power of Continuation Practice
One very powerful aspect of US patent law is its continuation practice. The patent statute allows applicants to file an additional patent application based on an earlier still-pending application and pursue different claims as long as those claims are supported by the first application. The key is that in order to file a continuation there has to be an earlier application that has not gone abandoned or issued as a patent. The continuation application gets the same effective filing date as the earlier application. Thus, even though it has different claims, the universe of prior art that can be asserted is the same.
Why is this a powerful practice? Because it allows patentees to wait and see what their competitors are doing and potentially draft claims that cover their competitors’ products, even if those products are new, as long as the original patent application on which the continuation is based has the information that will be claimed. You cannot add new information, but you can add new claims that are fully disclosed by the information that was already in the application.
It is important to understand that an invention may often be claimed in a variety of different ways, and it is the claims that determine the scope of protection. Inventions often have several features or combinations of features that are novel and non-obvious. Each set of novel and non-obvious features may form the basis for a set of claims. When we file an application, we do not necessarily know what competitors will think is important or what kind of products they might develop. So, if you keep a continuation application pending, you can see what emerges and potentially draft new claims to cover it.
This may seem unfair to some, but US law recognizes that a patent application may include many inventions and typically only allows one invention to be claimed per patent. Continuation practice allows inventors to more fully benefit from what they have disclosed despite how it might initially be claimed. Europe and many other countries seem to have a different philosophy. While they allow continuation applications (called “divisionals”) their rules restrict the extent to which a patentee can take information from the specification and draft new claims that were not in the original application at the time of filing. In the US it is far easier to draft claims after filing based on information that is included in the specification even if it involves combining features from different embodiments.
The other thing continuation practice does is to allow you to streamline prosecution. During prosecution, examiners will often allow some claims and reject others. Continuation practice allows you to get a first patent for the allowed claims and then continue to fight for the rejected claims in a continuation application. That way, you can more quickly get a good patent and fight for a better patent later.
The flip side of continuation practice is that if you are in a competitive space, you may need to watch the prosecution of your competitors’ patent applications so you can take appropriate measures if it looks like they could draft claims that cover your products. Because this practice is so powerful, it is not uncommon for some patents to have large chains of continuation applications.