Sorting Out the Rules on Patent Markings

May 2006

A patent marking is a notice that appears on a product that tells the public that the product is covered by either an issued patent or a pending patent application. For issued patents, the marking includes the words “U.S. Patent No.” and then the applicable patent number. For pending patent applications, the marking simply says, “Patent pending.” Clients sometimes confuse the appropriate use of these marks; for example, “patent pending” means that a patent application has been filed and you are waiting for your patent to issue (or not to issue). It does not mean that you and your attorney are working on a patent application that you have not yet filed. The term “patented” means that you have actually obtained an issued patent; it does not mean that you have filed your patent application.

The Patent Act imposes an affirmative duty on patent owners to include patent markings on their products. The purpose of this requirement is to notify the public that the device is covered by an issued patent (or a pending application) and should not be copied. In this respect, patent markings serve a deterrent purpose. The obligation to include patent markings does not apply to patented processes; however, if the product infringes both apparatus and method claims and the patent holder fails to include a patent marking on the product, the patent holder cannot escape the consequences of a failure to mark by simply asserting infringement of the method claims. Courts have held that where there is a product that can be marked, the patent holder must do so. Only where a patent involves method claims only is the patent holder relieved of the obligation to mark.

Although “patent pending” markings are appropriately used for products that are the subject of pending patent applications, those markings are not required by law. In the case of issued patents, however, patent markings are required. The marking must be placed on the product itself; it can 

be placed on the packaging or on a product label only if it is physically impossible to put the marking on or in the product itself. The fact that it may be more expensive to include the patent marking on the product itself as opposed to putting it on a product label is not sufficient justification. The patent marking must also be legible.

The consequence of failing to include a proper patent marking is that the patent holder cannot recover monetary damages for any infringing activities that occurred prior to the inclusion of appropriate patent markings on the product. The only exception to this rule is where the patent holder provides the infringer with actual, written notice of infringement. The notice must identify by number the patents at issue, but it need not set forth with specificity the patent holder’s arguments in support of infringement. The filing of a lawsuit against an infringer constitutes actual notice. General publications referencing the patent numbers at issue are not sufficient; instead, the notice must be specifically directed to the infringer. Patent markings, on the other hand, are considered constructive notice.

The patent marking requirement applies to licensees as well as to patent holders. Thus, every patent license agreement should include a provision requiring the licensee to include appropriate patent notices on the licensed products.

The failure to include patent markings on patented products affects only the ability to collect monetary damages and does not affect the patent holder’s right to obtain an injunction. False marking, i.e., marking an unpatented product with a patent number or using the “patent pending” designation where no patent application has been filed, will subject the person responsible for such false designations to a fine of $500 per offense. Continuing to mark products for which the patent has expired is a form of false marking. It has been argued that an egregious pattern of mismarking should be treated as a type of unlawful extension of the patent, which would fall under the patent misuse doctrine. Patent misuse is a defense to patent infringement.


Amicable photo of Toni

Antoinette M. Tease, P.L.L.C.