Patent Drafting 101: Going a Mile Wide and Deep with Variations in a Patent Application

“You absolutely want to file a patent application with a description that is a mile wide — that part is good — but you also need to also drill down far more than one inch deep in order to teach the various nuances of at least the key aspects of the invention.”

The goal of a patent application is relatively simple: To teach others what your invention is and how to both make and use the invention. Whenever I explain this to inventors I receive a common question: Why would I ever want to describe my invention to the point where others could simply copy it? The simple reason is that the US patent laws require such a description. The more complete answer is that such a detailed description of the invention is required in order for the government to grant a patent. Congress has established laws that mandated an invention be described with sufficient detail so that others will be able to benefit from it, learn from it, use it and advance it moving forward — all without the assistance of the inventor.

The only way to do this is by describing your invention with great care and specific detail. That is the price you pay in order to obtain a patent. If full disclosure is too much for you then you need to consider a trade secret, which is some circumstances is quite beneficial, but it is always important to remember that a trade secret lasts only so long as the information remains secret, which may be a sufficiently long period of time or may be quite short.

If you do decide to move forward with 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 many, particularly new inventors, business executives and newbie patent attorneys or agents, it is difficult to understand the so-called description requirement to patentability. It seems easy enough to comprehend as a general matter, but it is overly simplistic to merely say that a patent application must describe the invention. Those who fail in efforts to describe the invention insofar as this adequate description requirement is concerned do so overwhelmingly because they do not have a full conceptualization of what it is that they have as a protectable invention.


Notice my choice of words carefully. I am not saying that inventors do not know what they have invented; inventors most assuredly do know what they have invented, at least if there is a patentable invention. What inventors, and newbie patent attorneys and agents fail to appreciate, however, is that far more than what has been invented is patentable. Still further, even those who do appreciate the full glory of what can be protected frequently fail in providing what an experience patent attorney would call an adequate description because they only describe the invention in language that is one inch deep and a mile wide. You absolutely want to file a patent application with a description that is a mile wide — that part is good — but you also need to also drill down far more than one inch deep in order to teach the various nuances of at least the key aspects of the invention.

And there are always nuances that can go a mile deep for any and every invention, no matter how simple it may seem to you as the inventor. Of course it seems simple to you! After all, you are the inventor. Therefore, it is absolutely essential that inventors take a step back and affirmatively work to see the bigger picture. See Thinking outside the box leads to the best patent. Don’t think of your invention or any aspect of it as simple, think of it as an elegant solution. Do not assume any particular knowledge on the part of the person you are writing for, and consider describing everything as if you are writing for someone who is blind, this will force you to better appreciate those nuances you likely see as simple or commonplace. See Learning from common patent application mistakes.

It is critical to drill down past the mile-wide description of your invention for many reasons, but from a practical standpoint let’s remember that you will file your application anywhere from about 12 months to 24 months before you are likely to receive a first office action from a patent examiner. By the time you do get consideration from a patent examiner you are going to definitely want to have various levels of specific detail in the application so that you have nuances to layer on to the broad claims you filed so as to be able to convince the patent examiner that you have patentable matter. Without nuances in the specification you will be out of luck if and when the patent examiner finds good prior art to use against you.

The crux of the adequate description requirement is the enablement requirement, which can be found in 35 U.S.C. 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.

Also contained in 112(a) is the best mode requirement.  With passage of the America Invents Act the best mode requirement has largely, although not completely, meaningless.  It is still a requirement under 112(a), but there is no teeth to the requirement because the failure to disclose the best mode cannot invalidate a patent claim[1] once it has been obtained.  So at best the best mode requirement is now a toothless tiger.  Notwithstanding, generally speaking most inventors will undoubtedly want protection for what they perceive as the best mode (i.e., the best way to do things), which means you will need to disclose the best mode in order to claim the best mode. See Not disclosing preferences in a patent application still a big mistake.

The enablement requirement, which does remain in full force and effect, requires the applicant to describe his or her invention in a manner that would allow others in the industry to make and use the invention.  The enablement requirement looks to the objective knowledge of one of ordinary skill in the particular field or technology area (generally referred to in patent terms as “one of ordinary skill in the art”) and works to require the inventor to describe the invention, and all aspects and variations thereof, with the greatest amount of detail that can be provided. Essentially, enablement looks to place the subject matter of the patent claims generally in the possession of the public.


One of the challenges that a drafter faces when trying to satisfy the enablement requirement is with respect to describing things that can and will vary depending on the circumstances.  What you want to do is follow up by explaining the various permutations to help the reader more readily understand what facts, choices or circumstances will have impact.

For example, compare these five statements (which are used for illustrative purposes, not as medical advice):

(1) “Adults can take 2 capsules of X to relieve pain every 6 hours.”

(2) “Adults can take 2 capsules of X to relieve pain every 6 hours, but no more than 8 capsules in any 24 hour period.”

(3) “Adults should ordinarily take 2 capsules of X to relieve pain no more than every 6 hours, with a maximum number of capsules taken being 8 in any 24 hour period. These recommendations may vary depending upon the situation.”

(4) “Adults should ordinarily take 2 capsules of X to relieve pain no more than every 6 hours, with a maximum number of capsules taken being 8 in any 24 hour period. These recommendations may vary depending upon the age, weight and height of the person taking the capsules.”

(5) “Adults should ordinarily take 2 capsules of X to relieve pain no more than every 6 hours, with a maximum number of capsules taken being 8 in any 24 hour period. These recommendations may vary depending upon the age, weight and height of the person taking the capsules. If you are going to take more than 8 capsules in any 24 hour period you should first consult your physician.”

Notice how each statement provides more and more information, with statement 4 including both the general, as well as at least some information to guide the reader in understanding when what is preferable may be deviated from. Statement 5 even builds upon that to give the reader an action item with respect to deviation from the standard.  Of course, if your invention related to a method it would not be enough to say that recommendations depend on some identified variables. You as the inventor must go the next step and explain the relationship and how someone would make the determination. So while you want to aim for is something far more like (4) or (5) than like (1), even (4) or (5) would not be sufficient in a patent application.

How do you know how far you need to go? An excellent question. You really should strive to remove doubt and questions from the reader’s mind. While a certain amount of experimentation is allowable, and patents do not need to contain blueprint level detail, ask yourself whether a knowledgeable reader would know from what you’ve written enough to understand your invention without asking additional questions. If answers to additional questions would be necessary to fully comprehend the invention — in this case a method — then answer those questions. Perhaps there is a formula to determine dosage based on age, weight and height. If there is then disclose that formula. If the formula varies depending upon age or sex, consider including a table that provides illustrative dosage information (to continue with this example).

The key thing to remember is this: The point of a patent application is to convey information. Drawings, charts, tables, and formulas can and frequently are very helpful, as are illustrative examples. Convey information with a variety of tools and mechanisms. Words are but one way to convey information, and when you include drawings, charts, tables and formulas you will find it even easier to describe in words what is being shown/disclosed.

In the above example the invention relates to a method, but the need to disclose variations depending on circumstances is not unique to method inventions.  A patent application needs to define the actual physical characteristics of the components of the invention.  You can do this by describing a generic version of the invention and then ever more detailed alternative embodiments, some of which may include certain pieces, parts or features that will appear some, but not all, of the time.

When dealing with a tangible invention, patent applications need to define the structure of the overall invention, but also the structure of the components.  It is important to describe everything so that the reader will be able to picture the invention in their mind.  This may seem a silly comment for some inventors and newbie patent attorneys or agents because they frequently will think certain aspects of their invention are inherent in what they have already said, but remember, a patent application needs to explain the invention to someone who is not already familiar with the invention.

The best way to explain an invention to someone who is not already familiar with the invention is to explain it like so many of us used to do when we were kids doing a show and tell at school.  A child doing show and tell explains everything, no matter how obvious or inherent.  Kids do this when they describe things because they have no idea what the person listening knows, and to them it is new and interesting so they explain everything with tremendous detail (whether you want to hear it or not).  That is exactly what should be done in a patent application.  Explain the invention with so much detail that you will bore the knowledgeable reader to death.  That won’t make for entertaining reading, but it sure will make for a wonderful disclosure that will support a great many claims and can become the foundation of a patent portfolio if the invention ultimately becomes lucrative enough to warrant it.


Additional Information

For more tutorial information please see Invention to Patent 101: Everything You Need to Know. For more information specifically on patent application drafting please see:



[1] Throughout this article I periodically mention patent claims. The patent claims are the part of the patent that will define the exclusive rights actually granted. The written description must support the claims. This article focuses on the written portion of the application that supports the claims, which is called the “specification.” For more discussion of patent claims please see An Introduction to Patent Claims, which contains many links to related articles.



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Join the Discussion

2 comments so far.

  • [Avatar for Gene Quinn]
    Gene Quinn
    September 24, 2017 05:57 pm


    You can always file a continuation, but generally speaking there is nothing to be gained by holding back. The best advise is almost universally to describe everything you can at the time you file. If the invention is a work in progress and you later come up with more to disclose that is a perfect situation for a continuation.


  • [Avatar for Guy Letourneau]
    Guy Letourneau
    September 24, 2017 05:05 pm

    Would it be advantageous to write a specification “a mile wide,” also describing (disclosing) several “mile deep” descriptions in the spec, broad claims and also some detailed claims to drill down into of one species within the spec, preferably the most valuable, knowing that you can file continuations to drill down and claim other species while the parent is still pending?