Infringement or active inducement of infringement is willful when it is done deliberately and intentionally, and with knowledge of the patent. Copying of an invention, if such copying continues after the existence of the patent is made known, is evidence of willfulness.
However, infringement or active inducement of infringement is not willful if it is done with a good faith belief that the patent is either invalid or not infringed. The burden is on the patent owner to show willfulness by clear and convincing evidence. Power Lift, Inc. v. Lang Tools, Inc., 227 U.S.P.Q. 435, 438 (Fed. Cir. 1985).