The United States Court of Appeals for the Federal Circuit has recently confirmed in Droplets, Inc. v. E*Trade Bank that a claim for priority must be made expressly within a patent application. In other words, a claim for priority cannot be made through incorporating by reference an earlier application with its own express claims for priority. According to the Court, the burden is on a patentee to provide a clear, unbroken chain of priority.  In this case, with the loss of the priority claims that were not expressly made in the application, all of the claims of the patent at issue were held to be invalid as being obvious.

As a further gloss, for patent applications filed after 16 September 2012, US law requires that the claim for priority must be made in a properly signed Application Data Sheet.  The decision in Droplets, Inc. serves as a reminder of the importance of carefully ensuring all procedural requirements are met when filing patent applications to avoid a loss of substantive rights.

Read the full decision here.