© 2004, Dawsey Co., LPA
April, 2004

Current patent law no longer requires that a patented article be marked with the patent number in order for the owner to recover damages from an infringer. However, the law provides some hurdles for the owner of an unmarked article that make patent marking a worthwhile consideration.

First, patent owners need to understand the legal requirements for a valid marking of a patent. 35 U.S.C. § 287(a) states that while a patent owner “may” mark a patented article, a valid mark consists of the word “patent” or the abbreviation “pat.,” together with the patent number on the article. In cases where the nature of the article would not practically allow for direct marking, marking may be provided on a separate attached label.

The marking places prospective infringers on constructive notice of the patent and allows for recovery of damages for infringement without proof of notification to the alleged infringer of the infringement. However, when a patent is not properly marked, the law provides that no damages shall be recovered for infringements occurring before the infringer was given notice of the infringement and thereby given a chance to stop the infringing activity. When such notice is properly given, and the infringer continues the activity, recovery is limited to infringing acts committed after the notice.

Obviously, when a patent is directed solely to a method, there is no physical product to mark, and an owner is excused from a duty to mark. However, a lesser known but dangerous situation occurs when a patent, as is commonly found, rests on both method and apparatus claims. In such a case, if the apparatus is not marked, the failure to mark acts as a failure to mark for both method and apparatus claims. The reasoning of the courts is exemplified by the decision in the case American Medical Systems, Inc. v. Medical Engineering Corp., where the Federal Circuit held that the existence of a tangible piece of apparatus gave the opportunity to a patent owner to mark, and therefore potentially warn infringers of a patent covering both apparatus and method. Consequently, a failure to mark deprived users of a fair chance to appreciate the dangers of possible infringement.

There are circumstances when a strategy not to mark patented devices can be a good one, for example, when an owner wants to make it harder for potential infringers to obtain a copy of the patent and design around the device. However, such a strategy requires a higher level of vigilance in detecting infringers, and should be formulated in consultation with your patent attorney.