Collateral estoppel and why change claim language in related applications
On first impression, decisions under U.S. patent laws may seem like they are based on technicalities, but they attempt to actually address the underlying issues of a case. To that extent, U.S. patent laws are fair to the patent owner and to the public. Ohio Willow Wood Co. v. Alps South, LLC (Fed. Cir. 2013) appears to be nit picking about the nuances of collateral estoppel in relation to patent infringement cases but the court is really trying to be fair to the parties.
Collateral estoppel protects a party from having to re-litigate issues that have been fully and fairly tried in a previous action and were adversely resolved against a party-opponent. For example, if a claim in a first patent was held invalid in a first lawsuit, anyone in the future involved in patent litigation based on the same patent (i.e., first patent) does not need to prove that such claim is invalid in a second lawsuit. The first lawsuit established that. The issue in Ohio Willow Wood is whether a claim in a different related patent (i.e., second patent) in a second lawsuit could be held invalid based on the similarities between the invalid claim adjudicated in a first lawsuit and the unadjudicated claim in the second patent.
In Ohio Willow Wood, the Federal Circuit explained that collateral estoppel is not limited to patent claims that are identical. In other words, the claim in the second patent need not be identical to the invalid claim in the first patent for collateral estoppel to apply. Mere existence of different language does not preclude application of collateral estoppel. Rather, collateral estoppel looks to the “identity of issues,” that is, “[i]f the differences between the unadjudicated patent claims and adjudicated patent claims do not materially alter the question of invalidity, collateral estoppel applies.” (emphasis added). In this sense, U.S. patent laws attempt to resolve the underlying issues and do not brush aside the issues based on technicalities (i.e, mere existence of different claim language). Everyone is allowed at least one bite at the apple. Everyone can have their day in court. However, once you have taken your one bite, you are not allowed to take a second bite under the collateral estoppel doctrine. For example, competitors do not have to worry that the patent owner will sue them on a patent that has previously been held invalid. As such, patent owners need to vigorously argue for the validity of their patent during litigation.
In the present case, the Federal Circuit explained that the unadjudicated claims of the second patent described the invention in similar terms to the adjudicated claims of the first patent, and thus did not create a new issue of invalidity. As for those terms that were different between the two claims, the Federal Circuit explained that the patent owner failed to explain how those differences alter the invalidity determination. For example, the invalid claim in the first patent required a polymeric gel, whereas the claim in the second patent required a “block copolymer”. The Federal Circuit found that the patent owner failed to provide any explanation regarding how the “block copolymer” limitation is patentably significant in view of the obviousness determination regarding the claim reciting the polymeric gel limitation. Hence, the unadjudicated claim in the second patent was held to be invalid for being obvious since the adjudicated claim in the first patent was held to be obvious under the doctrine of collateral estoppel in the first lawsuit.
During patent prosecution, a second patent application can be filed even if a patent issues on a first patent application as the patent owner did in Ohio Willow Wood. The second patent application is a mere refiling of the first patent application and may be used for various purposes such as broadening some of the limitations in the claims of the first patent. Sometimes, different wording is used to claim the same invention as the first patent in an attempt to preclude the application of collateral estoppel as was attempted in the Ohio Willow Wood case. Even though Ohio Willow Wood failed to preclude the effects of collateral estoppel, it is still a good strategy to file continuations for such purposes because you will have the option to make such arguments during litigation as long as different claim language is used.
I invite you to contact me with your patent questions at (949) 433-0900 or [email protected] Please feel free to forward this article to your friends. As an Orange County Patent Attorney, I serve Orange County, Irvine, Los Angeles, San Diego and surrounding cities.