Patent Drafting: Appropriately Disclosing Your Invention

Drafting patent applications is a frequent topic on In fact, we are in the middle of a series on patent drafting written by Joe Root, author of Rules of Patent Drafting: Guidance from Federal Circuit Cases. The series by Root has patent attorneys and patent agents as the primary audience. This article, as well as other basic patent drafting articles, are more aimed at independent inventors or others who are relative novices.

The focus of this particular article is on the disclosure of the invention in the specification. While it is true that the claims will define the exclusive rights that are granted to the patentee, the specification provides the information through which the claims are read. The specification provides the detail that defines what the claims mean, and as the result of a variety of cases over the past few years the specification is becoming an increasingly important part of the patent application. It has always been required and very important, but Courts seem to be marching the United States toward a strict technological advancement standard, which means the technology, mechanics, structure, architecture and environment in which the invention is used really needs to be described with as much detail as possible in order to guarantee that the claims are viewed as covering an innovation and not something trivial or unimportant.

The lens through which the sufficiency of the specification is evaluated is provided by 35 U.S.C. 112(a), which generally speaking requires the patent application to disclose the best mode of the claimed invention, describe the invention so that it could be made and used by others, and so that the written description demonstrates that the patent applicant is truly in possession of an invention rather than simply theorizing. We will cover each of these requirements in turn.

About the Best Mode Requirement

The first thing that needs to be mentioned is that the best mode requirement continues to live on, at least to some extent. When Congress passed the American Invents Act (AIA) the best mode requirement was watered down, but not removed. It is now no longer possible to challenge issued claims as being invalid because the best mode of the claimed invention was not disclosed. However, 35 U.S.C. 112(a) still requires that inventors disclose the best mode. Thus, if you can get a patent without disclosing the best mode there are no negative ramifications, unless of course you did so in a way that could be considered to be fraudulent. But in the unlikely circumstance where the patent examiner discovers a failure to disclose the best mode patent claims can be denied. A strange situation, but no matter. Inventors are almost always (i.e., 99.99% of the time) better off disclosing the best mode so that it can be specifically claimed. After all, don’t you want your patent claims to cover the version of the invention that you deem to be best? Generally the answer is a resounding YES!

Inventors must disclose what is called the “best mode” of their invention. This means that if you have any preferences you must disclose them, although the best mode requirement doesn’t mean that you have to go out in search of preferences if none exist.

The sole purpose of the best mode requirement is to prevent inventors from applying for patents while at the same time concealing any preferences that relate to any aspect of the invention conceived.  Nevertheless, it is very important for you to describe your invention not only in terms of what works best, but also in terms of what works at all.  If your invention becomes a success there will be others who will seek to legally copy your invention, which means they will do what you leave uncovered.  For this reason you really need to ask yourself what modifications can be made to get around what you have described?  This is a critical question to ask yourself because if you are making money and have a successful invention others will want to copy you and if they can copy you with meaningless changes that are not described in your application then they will be able to do that, compete with you and not infringe your rights.


About the Enablement Requirement

In order for an application to be complete the invention must be enabled.  What this means is that the disclosure must explain enough so that someone skilled in the art can both make and use the invention.  The purpose of this requirement is to require applicants to truly put the invention into the public domain.  The reason the public must be completely informed is because after the patent expires anyone can make, use, sell or import the invention covered by the patent claims.  Therefore, in order to ensure that the public can derive benefit from inventions after the term of exclusivity has expired the patent applicant must explain how to make and use the invention.

Many time inventors believe the various uses for their invention will be clear, and perhaps to some they would be clear.  Even though the patent laws say you need only enable one who is skilled in the relevant field, it is always the best practice to try and provide a disclosure that would allow a reasonably educated person to understand the invention.  This being the case, I suggest you take a critical look at this to see if someone who is unfamiliar with your invention would understand how to use the invention after reading your disclosure.  It is very important to explain with as much detail as possible how one would use your invention, paying particular attention to unobvious or counter-intuitive steps, and paying particular attention to any preparations that may be necessary prior to beginning.

It is also vitally critical for inventors to understand that the strength and breadth of your disclosure will be determined not only by the general descriptions, but by the specific descriptions that explain various embodiments.  Inventors frequently want to only describe things very generally, and that is a recipe for disaster. If you describe things so broadly it will be easy to find prior art for the invention disclosed, which means no patent may be able to be obtained. Resist the temptation to hold back on the specifics. If you don’t want to provide the specifics that is fine, but then you really shouldn’t be applying for a patent at all.

When you describe an invention you always want to start generic and then increasingly get more specific.  Just watch to make sure that you talk about the specifics in terms of permissive language (i.e., may, can, preferably, etc.) rather than in terms of mandatory language (i.e., must, shall, required, etc.).  Of course this cautionary note presumes that certain specifics you add are indeed optional.  The point is to take care to describe things so that they work, but don’t make anything mandatory that is an optional feature.

As already stated, a patent needs to explain to those skilled in the art how to make and use the invention.  Having said this, however, a patent does not need to be a blueprint, and engineering drawings are not required in a patent. The law says that you must describe the invention that does not lead to the need for what is called “undue experimentation.”  This means you need to explain the invention so that it could be made in used without individuals having to go through a trial and error process to figure it out for themselves. Some level of tinkering is fine, but a patent needs to teach the invention and not just vaguely point the reader in a general direction.


About the Written Description Requirement

The written description requirement is to ensure that a patent is limited to what the inventor has specifically invented; stated in patent terms the written description requirement is used (in part) to ensure that the inventor is in possession of the invention.  In order to demonstrate possession of an invention it is important to demonstrate possession of both generic and specific embodiments.  So, there is no substitute for describing the specifics of use and structure.

One very good way to describe an invention is to start off with a general description or characterization, and then to provide examples.  An example would be: “Component A is attached to component B.” Notice, however, that this description is vague and could encompass all kinds of various connections, including connections that you don’t envision and which may not work.

So now take that general description and add a little more: “Component A is attached to component B. This attachment of A and B may be accomplished through the use of rivets, nuts and bolts, clamps or by welding.”  In this formulation A and B are generically attached, but then there are various specifics that are suggested as possibilities.  Notice the use of the permissive “may be”, which does not require these types of attachments, but instead makes these types of attachments illustrative.  Always be careful not to make anything mandatory that is truly optional.

It is very important that a patent application completely define your invention.  Merely saying that different versions can exist, or that things can be done differently, or that alternative configurations are possible is one step, but without more you are not teaching what these alternatives are, which means they are not considered to be disclosed in your application.  The written description requirement states that you need to define your invention so that the reader will be able to appreciate exactly the boundaries of what you have invented.  When you say that other, undefined and unexplained variations can be made you are not defining the boundaries in a bright line way.  The point is that there is nothing wrong with starting out broad and general, but then you want to take the next step and describe these other variations with as much detail as possible.

Additional Reading

For more information on patent application drafting please see:



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Join the Discussion

3 comments so far.

  • [Avatar for Anon]
    September 1, 2014 11:26 pm


    I think you over-react somewhat, possibly due to the apparent tightness in the EP regime for verbatim words. IT has been long practice in the states to include disclaimer type language that basically states that all combinations of the items discussed in the application are recognized and are in possession.

  • [Avatar for MaxDrei]
    September 1, 2014 05:16 pm

    Good point from Laurie. It prompts my thought, as follows.

    Is there any chance of a squeeze on prosecuting attorneys like the one there is in another First to File jurisdiction, namely Europe?

    The squeeze at the EPO arises when Claim 1 cannot hold. A narrowing amendment is needed. Yet no matter how hard you try, you cannot simultaneously satisfy with your amended text the conflicting requirements for i) a “written description” of the Invention as now claimed, in the app as originally filed and ii) an amended claim that is “definite” enough. And all because the meaning of your original written description was not reasonably certain.

    Watch out drafters. There are now lions in the path.

  • [Avatar for Ron Laurie]
    Ron Laurie
    September 1, 2014 11:35 am


    You mention 112 issues of best mode, enablement and written description, but after the recent Supreme Court decision in Biosig v. Nautilus, “definiteness” (or, more properly, indefiniteness) of claims has now become a critical issue in patent drafting. As I read the decision, claims must be drafted so that a skilled artisan reading the spec (and the file history??) will be “reasonably certain” of what is included in, and excluded from, the scope of the claim. While there is some overlap between the indeffinitteness and written description requirements on the one hand, and indefiniteness on the other, they should now be analyzed separately.