Patent law is virtually alone in intellectual property (IP) in punishing independent development. To infringe a copyright or trade secret, defendants must copy the protected IP from the plaintiff, directly or indirectly. But patent infringement requires only that the defendant's product falls within the scope of the patent claims. Not only doesn't the defendant need to intend to infringe, but the defendant may be entirely unaware of the patent or the patentee and still face liability. Nonetheless, copying does play a role in some subsidiary patent doctrines, including damages rules, willfulness, and obviousness. More significantly, the rhetoric of patent law (and of IP law more generally) often seems to presuppose that defendants in patent cases are in fact engaged in copying. Similarly, the outcome of public policy debates over patent reform may well turn on the perception of patent infringers as either bad actors or as innocent businesspeople who accidentally ran afoul of a patent. Unfortunately, no one seems to know whether patent infringement defendants are in fact unscrupulous copyists or independent developers. In this paper, we seek to answer that question. We look both at the allegations made in a random sample of complaints and at the treatment of copying in recent reported decisions, including willfulness decisions. We find that a surprisingly small percentage of patent cases involve even allegations of copying, much less proof of copying. Copying in patent law seems to be very much the exception, not the rule, except in the pharmaceutical industry.
Christopher A. Cotropia & Mark A. Lemley, Copying in Patent Law, 87 N.C. L. Rev. 1421 (2009).