Complying with the Statutory Written Description Requirement in a U.S. Utility Patent Application

Failure to comply with the written description requirement can result in a patent application being rejected or can be the basis for challenging validity of a patent.

The U.S. patent system, which has its origin in the U.S. Constitution, provides as an incentive for inventors to disclose their inventions a limited exclusionary right during the term of the patent. More specifically, an inventor, or the inventor’s assignee, has the right to keep others from making, using, offering for sale, selling, or importing the claimed invention. After expiration of the patent, the public obtains the right to make free use of the invention. In order for this right to be meaningful, the invention must be described in such clear and detailed terms that the public is provided with adequate guidance regarding how to practice the invention.

Section 112 of the Patent Act states

“The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.”

One cannot obtain a valid patent while playing one’s card so close to one’s vest that the requirements of this paragraph are not met. The patent application is addressed to one who is skilled in the art to which the invention pertains. The application, therefore, need not contain disclosure of what is already known to those skilled in the art. In fact, there are court opinions stating that it is preferred that such information not be included.

A part of the written description requirement is that an “enabling disclosure” must be provided. This requires that one skilled in the art or science to which the invention relates would be enabled from the disclosure to practice the invention without having to engage in “undue experimentation.” The mere fact that some experimentation is required does not mean that disclosure fails to satisfy the enabling requirement. There are instances wherein reasonable minds could differ. It is best to err in the direction of providing additional details above and beyond what might arguably be provided in satisfaction of the minimum enablement requirement.

Another portion of the written description requirement is that the invention contains a description of the “ best mode” of practicing the invention known to the inventor at the time of filing the application. This portion of the requirement involves the inventor’s good-faith belief at the time of filing. It prevents the inventor from withholding the form of the invention believed to be the best mode while seeking to obtain a valid patent. It also does not matter if the inventor, in good faith, believes a particular approach is the best mode as of the filing date and later learns that there is a better mode so long as there was good-faith compliance as of the filing date.

The written description also should set forth, in detail, the invention for which a patent is sought in such a way as to distinguish it from prior art inventions. It should describe completely one or more specific embodiments of the method, machine, product, composition of matter, or improvement invented, and the manner and method of making and using the invention.

In chemical and metallurgical cases, it is common to provide experimental data that helps to define the invention including, where applicable, broad operable composition ranges or process parameters such as temperature, time and pressure, as well as narrower preferred ranges. Such data may also include comparative data that compares the invention with related performance of prior art. Such content may also be employed with respect to other technologies. Where appropriate, examples disclosing how to use the invention may be provided. These examples may be actual test results or hypothetical examples that have instructional value.

It will be appreciated, therefore, that the written disclosure requirement serves to satisfy the objective of the public obtaining ready free use of the invention once the patent has expired.

As will be apparent, it is critical that inventors make clear and complete disclosures of their inventions to their intellectual property attorney in order that a patent application that satisfies the written description requirement can be filed.

Arnold B. Silverman is chair of the Intellectual Property department and a member of Eckert Seamans Cherin & Mellott, LLC in Pittsburgh, Pennsylvania.

For more information, contact A.B. Silverman at Eckert Seamans Cherin & Mellott, LLC, 600 Grant Street, 44th Floor, Pittsburgh, Pennsylvania 15219; (412) 566-2077; fax (412) 566-6099; e-mail abs@escm.com.