Posts Tagged: "ArcelorMittal v. AK Steel Corporation"

Defensive Collateral Estoppel Applies Only if Essentially Identical Accused Product Found Non-infringing

In its opinion, the Federal Circuit explained that defensive collateral estoppel of non-infringement applies in very limited circumstances where “a close identity exists between the relevant features of the accused device and the device previously determined to be non-infringing such that they are ‘essentially the same.’” Accused products are essentially the same where “the difference between them are merely ‘colorable’ or ‘unrelated to the limitation in the claim of the patent.’” Thus, “[i]f accused devices in a second suit remain ‘unchanged with respect to the corresponding claim limitations at issue in the first suit,’ the patentee is precluded from pursuing its infringement claims a second time.” The burden is on the proponent of claim or issue preclusion to show that the accused products are essentially the same.