Look at a few patents and you’ll see that almost all of them have drawings to show what the invention looks like. Today, we’ll talk about the importance of patent drawings in a patent application and what the U.S. Patent Office says are the requirements.

Note that this article is going to discuss patent drawings for a utility patent application which protects how an invention works. To read about patent drawings for a design patent application which protects how an invention looks, see the article From Concept to Protection: Applying for a Design Patent.

Explain How the Invention Works

An important concept in applying for a patent is that your patent application must explain how your invention works. This is written in the U.S. patent law which says a patent application must “enable any person skilled in the art … to make and use the [invention].” 35 U.S.C. 112. This means that to be even considered for a patent, you must first explain in your patent application exactly how your invention works so that someone can “make and use” your invention.

Inexperienced inventors applying for a patent sometimes make the mistake of being unclear in their patent application because they don’t want to reveal all the secrets of how their invention works. Doing so is a major mistake. If you don’t fully explain how your invention works, you haven’t met the first requirement of even being considered for a patent. Make sure when you are preparing a patent application with a patent attorney or patent agent, you disclose as much detail as possible as to how your invention works. Otherwise, someone could say you didn’t explain your invention in enough detail to deserve a patent.

How do patent drawings come into play? Well, drawings help you explain how your invention works. To satisfy the patent requirement that you explain how your invention works, you’ll use drawings to support the written portion of your patent application. Someone reading your patent and looking at your patent drawings must be able to understand how your invention works so that they can “make and use” your invention. If you fail to meet this requirement, you won’t get a patent.

Illustrate Each Feature of the Invention Claimed

How much of your invention do you need to draw? The U.S. Patent Office says a utility patent application “must show every feature of the invention specified in the claims.” 37 CFR 1.83. This means every important feature of your invention must be shown in your patent drawings. In a utility patent application, you must write patent claims which defines what features of your invention the patent covers and also how strong your patent is. For every feature of your invention that you claim, you must show it in the patent drawings.

Reference Characters Show the Invention’s Features

For each feature of your invention that you claim in your patent claims, you should assign it a unique number called a reference character. On your patent drawings, you then label each feature with its unique reference character.

For example, looking at the patent drawing at the top of this article, the head of the golf club is labeled with the number 5 and the shaft of a golf club is labeled with the number 9. Then, when you write about how the golf club works in the patent application, you put the number 5 after each mentioning of the golf club head and you put the number 9 after each mentioning of the golf club shaft. By doing this, when people read your patent application and they see you write about the golf club shaft followed by the number 9, they can then go find number 9 on the patent drawings to know which part of the invention you are talking writing about. The patent drawings with reference numbers help the reader of your patent application understand how to “make and use” your invention so you can meet that requirement necessary to apply for a patent. 

Conclusion

Patent drawings are important in a patent application to help explain how your invention works. Make sure you show every feature of your invention that is important. Depending on what your invention is, the drawings you need to provide may vary. For example, if your invention is a software app, you may need flow charts to show the software processes. If your invention is a pharmaceutical drug, you may need a structural formula to illustrate the molecular structure. Your patent drawing should be whatever is needed to show how your invention works.