When a patent owner alleges another infringed the patent, the owner inevitably also alleges that such infringement is willful. An accused infringer often defends a claim of willful infringement by asserting evidence that the accused infringer reasonably relied on the opinion of counsel. This article discusses the concept of willful infringement and the criteria necessary for an opinion of counsel to be deemed competent. Moreover, this article analyzes issues that arise as a consequence of using such patent opinions, with a special focus on attorney-client privilege and work-product immunity waiver. Finally the practical ways to minimize the problematic aspects of such patent opinions are addressed, with a focus on post KnorrBremse Systeme Fuer Nutzfahrzeuge GmbH v. Dana Cp. and In re Echostar Communications Corp. considerations.
William L. LaFuze, Exculpatory Patent Opinions and Special Problems Regarding Waiver of Privilege, 6 J. Marshall Rev. Intell. Prop. L. 313 (2007)