For clients concerned that their product or service might fall within the claim of another's patent, we often can provide an invalidity opinion that relieves the concern and/or insulates against an allegation of willful infringement.
A basic invalidity opinion typically depends upon references that are prior art to the patent claim of concern, and/or the prosecution history of that claim, to identify why the claim fails to legally meet the patentability requirements.
A more advanced opinion might rely upon evidence of prior art activities and/or statutory bar activities.
In some situations, the opinion can explore potentially illegal activities by those associated with the patent that might lead a well-informed court to issue a judgment that all of the claims of the patent are unenforceable.