Legal Definitions - interference-estoppel rejection

An interference-estoppel rejection is a refusal by a patent examiner to grant a patent claim because the applicant is legally prevented (estopped) from asserting that claim. This prevention arises from a prior "interference proceeding," which was a specific type of legal process historically used by the U.S. Patent and Trademark Office (USPTO) to determine who was the first inventor when multiple parties claimed the same invention.

The principle of estoppel means that if an applicant had the opportunity to raise a particular claim or argument during a previous interference proceeding but failed to do so, or if they lost on that claim, they are generally barred from asserting that same or a similar claim in a later patent application. This rule promotes finality and prevents applicants from repeatedly trying to patent inventions that were, or could have been, decided in a prior dispute. It's important to note that interference proceedings were largely replaced by a "first-inventor-to-file" system in the U.S. after the America Invents Act (AIA) in 2011, so this type of rejection primarily applies to older applications or those still under the pre-AIA rules.

• Example 1 (Failure to Present Claims):

  Imagine two inventors, Alice and Bob, both filed patent applications for similar new types of solar panels. The USPTO declared an "interference proceeding" to determine who invented it first. During this proceeding, Alice focused her arguments and evidence on a specific design feature (e.g., a unique light-absorbing coating). She could have also presented claims for a different, related feature of her solar panel (e.g., an improved mounting system) but chose not to, or simply overlooked it. The interference concluded, determining Bob was the first inventor for the light-absorbing coating. Later, Alice files a new patent application, now trying to claim the improved mounting system. The patent examiner might issue an interference-estoppel rejection for these new claims. This is because Alice had the opportunity during the original interference to present all claims related to her solar panel invention, and by not doing so, she is now estopped from asserting them in a new application if they are considered to be within the scope of what could have been litigated in the prior interference.

• Example 2 (Lost on a Claim):

  Consider a scenario where two pharmaceutical companies, Pharma A and Pharma B, were involved in an interference proceeding over a new drug compound. Pharma A specifically claimed a compound with a particular chemical structure, and Pharma B claimed a very similar structure. The interference proceeding concluded that Pharma B was the first inventor of the specific compound claimed by Pharma A. Subsequently, Pharma A files a new patent application attempting to claim a slightly modified version of the exact same compound that was the subject of the prior interference, arguing it's a new invention. The patent examiner would likely issue an interference-estoppel rejection. Pharma A is estopped because they already had their chance to prove inventorship for that specific compound (or a very closely related one) during the interference and lost. Allowing them to re-litigate it through a slightly modified claim would undermine the finality of the previous proceeding.

• Example 3 (Broader Subject Matter):

  Let's say an inventor, Carol, and another inventor, David, were in an interference proceeding concerning a novel method for 3D printing. The interference specifically focused on a method using a certain type of polymer. Carol won the interference, establishing her as the first inventor for that specific polymer-based 3D printing method. However, during the interference, David could have argued that his method, while using a different material, was fundamentally the same inventive concept or that the scope of the interference should have been broader to include other materials. He didn't make that argument. Later, David files a new patent application for a 3D printing method that uses a different material but is structurally and functionally very similar to the method decided in the interference. The examiner might issue an interference-estoppel rejection. Even though the material is different, if the underlying inventive concept was or could have been litigated in the prior interference, David is estopped from now claiming it. The estoppel prevents him from asserting claims that fall within the scope of what was, or could have been, determined in the earlier proceeding.