Many patent applications are rejected upon initial submission, but they are almost never rejected with absolute finality. Further, subsequent to filing its original application a patent applicant might wish to write an application with broader or somewhat different claims, or perhaps add claims that were not made in the original application. Or it may wish to rewrite claims that had been rejected in the original application. A patent "continuation" is an application for additional claims made on a patent that was previously applied for.
Under generally accepted patent practices in the United States, when a subsequent continuation or divisional application is granted the subsequent patent "relates back" to the date of the original patent application, and will typically retain the original application's priority over rival filings. While continuations are an accepted and increasingly comon part of the process under which patents are granted, they can also bring anticompetitive abuse. In particular, the continuation process makes it possible for a patentee to write updated claims designed to exclude a rival's invention that has been placed on the market subsequent to the date of the original application.
Nevertheless, there is probably little room for application of the antitrust laws, given that the Federal Circuit has expressly approved the use of continuation and divisional applications to write updated claims on a competitor's existing products or technology. The notice and publication provisions are part of the law as well. While we believe such an approach to the giving of notice deters rather than promotes innovation, the fact is that conduct approved by law cannot form the basis of an antitrust claim when the patentee later files an infringement action based on such an after-acquired right.
This paper focuses on the implications of two Federal Circuit Court decisions involving patent holdup in the standard setting process. While the Rambus decision can be defended as a matter of antitrust policy, it exposes serious deficiencies in the patent continuation process that can legally permit anticompetitive holdup to occur. Broadcom, by contrast, is arguably not about antitrust policy at all, but rather the law of contract or equitable estoppel.
Hovenkamp, Herbert J., "Patent Deception in Standard Setting: The Case for Antitrust Policy" (2008). Faculty Scholarship. 1774.