Describing an Invention in a Patent Application

engineer-draftsmanWhen you file a patent application it is always necessary to file an application that completely and clearly describes the invention so that others would be able to understand the invention.  For new inventors it is sometimes difficult to understand the so-called description requirement to patentability. It is not an overstatement to say that the description of your invention must be so complete that it could be copied by others who read your patent application and/or issued patent. This is sometimes surprising to those new to the field who ask, “why would I want to describe it so others would know what to do themselves?” You must describe it with this level of detail because that is what is required by the patent laws and failure to describe the invention with such specificity will make it impossible to ever obtain a patent.

It is absolutely critical to understand that this complete and full description MUST be present as of the filing date of your application. If you file an application that does not describe the invention to the required level required by U.S. patent laws the application is defective and it cannot be fixed.  The only way to fix an inadequate disclosure is to file a new application with an adequate disclosure, but that means you obtain no benefit from the filing of the earlier inadequate patent application.


The crux of the description requirement, which is embodied in 35 U.S.C. § 112, is the enablement requirement and the best mode requirement. Both the enablement and best mode requirements can be found in 112(a), which 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.

The enablement requirement requires the inventor to describe his or her invention in a manner that would allow others in the industry to make and use the invention. The purpose of the enablement required is to place the subject matter of the patent claims in the possession of the public. This is a critical part of the patent bargain because once the patent falls into the public domain the invention, as well as all obvious variations of the invention, will be free to be used by anyone. The government grants exclusive rights to the inventor in exchange for disclosure. Society benefits by becoming informed and eventually being able to use the invention freely without any claim of ownership by the inventor.

The best mode requirement requires the inventor to disclose his or her preferred way of carrying out the invention at the time the patent application is filed. There is no requirement that the inventors preferred embodiment be updated as the patent application works its way through the Patent Office. Best mode looks to whether specific instrumentalities and techniques have been developed by the inventor and are known and preferred at the time the patent application is filed.

The failure to disclose the best mode is no longer a valid reason to challenge a patent claim once it has issued, but the law still nevertheless requires the best mode to be presented in the patent application. From a strategic standpoint inventors should want to disclose the best mode. Failure to disclose the best mode will foreclose the ability to claim what the inventor believes is best. Any patent application should always define everything that works, but most certainly should disclose and claim that which the inventor believes is superior.

Thus, the enablement requirement looks to the objective knowledge of one of ordinary skill in the art, while the subjective and factual best mode inquiry looks to the inventor’s state of the mind.  Together both work to require the inventor to describe the invention and all preferences with the greatest amount of detail that can be provided.

Anything that is included in the original filing of a patent application makes up what is called the “original disclosure.” For that reason, one highly effective way for inventors to help ensure that they are satisfying the adequate description requirement is for them to include multiple quality patent drawings. Whatever is shown in a drawing is considered to be disclosed. In my opinion, patent applications do not typically have enough drawings. Pictures really are worth at least one-thousand words. Further, if you create a standard patent application disclosure you will spend time discussing what each drawing shows. See Working with Patent Drawings. Thus, having good patent drawings is an excellent way to help ensure that the adequate description requirement is satisfied. See What Drawings do You Need? 

Finding ways to ensure adequate disclosure of the invention is essential. If something is not described in your patent application then it is not considered a part of your invention insofar as the patent laws are concerned. Thus, hiding the ball is not a useful strategy. In fact, hiding the ball is a strategy that will only succeed in preventing a patent from ever issuing.

For more information about patent drafting and disclosure requirements please see:


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One comment so far.

  • [Avatar for Benny]
    August 9, 2015 05:33 am

    If only the practice would follow the theory…I have seen many granted patents which are schematic at best, with claims such as “…processor configured to do X when input is Y” but not a hint in the specification regarding the complex algorithms which would be required for this to actually take place, while devoting paragraphs to describing the different types of battery that could be used to power the device.