Patent Drafting 101: The Basics of Describing Your Invention in a Patent Application

Patent definitionDrafting a patent application can be a daunting task, particularly when one does not have any experience drafting a patent application.

While perfectly true, the previous statement seems almost cavalier. Any complicated task is daunting when one does not have any experience. But then comes the realization, how can you get experience if you don’t even know where to begin? But where do you begin such a project if you don’t have any experience to even understand how best to approach the task?

There really is no magic to drafting a patent application, at least in theory. Yes, an experience patent practitioner who is familiar with the law and technological area relating to your invention can and will provide a great deal of value added to any patent project. Knowing how best to describe the invention and all of the aspects of the invention so as to maximize the likelihood of obtaining a patent while minimizing roadblocks and pitfalls that lurk for practically every invention. But there is no magic wand that will be waved and bottle rubbed that will make a patent application suddenly appear. It takes a lot of work, both in the drafting phase and in the phase of the project where the invention is being understood in relation to other known inventions.


I have been teaching patent application and claim drafting for nearly two decades. As with any complex endeavor the first critical step in the learning process is to read and understand as much as possible. If you are setting out to attempt to draft a patent application and you have never read a patent before you will be at a significant disadvantage. Indeed, sometimes when inventors have asked me to review what it is that they have drafted themselves I cringe. It is not uncommon to receive 50+ pages of text from an inventor with fewer than 5 pages actually being useful information that might actually wind up appearing in a patent application. I have to wonder whether these inventors have ever read a patent before.

One big mistake inventors make is they will go on page after page in their draft patent application about how they came up with the idea for the invention, what the market for the invention is and how they plan on tapping into that market. None of that is appropriate for a patent application. Various pieces, perhaps even all of it, would be appropriate for a business plan. So the first thing inventors need to understand and really internally appreciate is that a patent is NOT a business plan. If you are going to attempt to raise money to pursue your business objectives you will undoubtedly need a business plan and attaching a well drafted and previously filed patent application as an appendix can be useful at times, but a business plan and a patent application play very different roles.

If and when you start to read patents and set out to draft your own patent application you will notice that one of the sections of a patent is labeled Background of the Invention. It is important to realize that this Background section is NOT actually about your invention, but rather the need for the invention as the result of failure of other inventions to satisfy some desired functionality. The Background of the Invention is a misleading name, unfortunately, and likely why so many inventors spend a lot of time discussing irrelevant and even extraordinarily harmful information in patent applications they draft and file. See Beware Background Pitfalls.

When you file a patent application it is always necessary to file an application that completely and clearly describes the invention (see here and here) 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.  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 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 do not obtain benefit from the earlier filing of the inadequate patent application. This has always been problematic, but given that the U.S. moved to first to file in 2013 (see here and here) it can now result in a catastrophic mistake. For that reason you want to define the full glory of your invention, as well as any alternatives and variations.


Inventors frequently want to know why someone would describe their invention to the point where others could simply copy. xThe simple answer is this: If you do not provide that level of detail in your patent application filing the patent application is a complete waste of money. U.S. patent laws require such a detailed and specific description of the invention in a patent application. The reason goes back to the beginning of the patent system. The government is going to grant a patent on a new and non-obvious invention if and only if the inventor puts that invention into the possession of the public so that it can be understood and freely used by anyone and everyone once the patent expires.  So if you want a patent you need to disclose the invention with great specificity. If you do not want to describe your invention with that level of detail that is certainly fine, but you need to consider keeping the invention a trade secret if that is possible.

The crux of the description requirement, which is embodied 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.

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. “Enablement looks to placing the subject matter of the claims generally in the possession of the public.”

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 PTO. Best mode looks to whether specific instrumentalities and techniques have been developed by the inventor and are known at the time of filing as the best way of carrying out the invention.

The written description requirement serves to functions. First, the scope of the invention is defined at the time of the original filing of an application. Whatever is present at the time you file makes up that original disclosure and is entitled to that filing date. If you attempt to sneak something new in later that was not present at the time of the original filing that would be considered a written description violation. Second, the written description requirement acts as a logical limit on the scope of the invention you alleged to have. An extreme (and silly) example would be describing a wristwatch in a patent application and then in the claims attempting to gain rights to an H.G. Wells time machine. Yes, your application describes a particular time machine (i.e., a wristwatch) but disclosing a wristwatch would not allow you to claim anything that could be characterized as a time machine unless you specifically described that H.G. Wells time machine in your application. So, in this second configuration the written description requirements makes sure you are actually in possession of the invention you claim.


Together the requirements of 112(a) work to require the inventor to describe the invention and all preferences, alternatives and variations with the greatest amount of detail that can be provided.  Simply said, if it is not described in your patent application then it is not considered a part of your invention insofar as the patent laws are required and cannot be claimed.

One final word. The requirement that an invention be completely described in a patent application applies both to provisional patent applications and nonprovisional patent applications.

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:


Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of

Join the Discussion

4 comments so far.

  • [Avatar for Joachim CS Martillo]
    Joachim CS Martillo
    December 21, 2016 04:37 pm

    This comment section may not be the best place to ask this question, but it may be better than other discussions.

    If I construct a new, non-obvious, innovative plant by means of CRISPR technology (probably one or two tech generations in the future but probably < 10 years to wait for the necessary DNA editing equipment), should I seek a utility or a plant patent for my invention? I don't believe I will be able to apply for both, but maybe I am wrong.

  • [Avatar for Deepanshu Nagar]
    Deepanshu Nagar
    December 18, 2016 02:18 am

    That would be great, waiting for the course 🙂
    I also wanted to ask if you have country specific blogs, most of your articles are USA specific. If possible pls add IPR related issues from other countries as well(I am from India).

    Thank you

  • [Avatar for Gene Quinn]
    Gene Quinn
    December 17, 2016 04:45 pm


    Thanks for reading

    The answer to your question is — no… not yet. I do plan on rolling out some courses in 2017. Stay tuned.


  • [Avatar for Deepanshu Nagar]
    Deepanshu Nagar
    December 17, 2016 03:36 pm

    I am a law student and really interested to have a career in IPR laws. You have a worderful blog. I was wondering if you are having an online course type thing where students like myself can actually learn basics like drafting of patents and other topics ?

    Thank you