I used to use a sequential diagram for a process flow between multiple components, but have never seen it in patent documents. Is it not allowed?

Below is just an example of sequential diagram enter image description here

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    I don't know for sure so I'll leave it to someone else to answer. That said, I can't see why you can't use such a diagram assuming the specification explains it sufficiently. It is best if the diagram is readable entirely in black and white.
    – Eric S
    Commented Jun 22, 2018 at 18:59

3 Answers 3


I agree Eric Shain. In fact, this kind of diagrams are quite popular en communication protocol related patents, where interactions between sender and receiver have a sequential order. For example, figures 3, 4 & 5 in Amazon patent US6675196; figure 2 in ATEN patent US7716404B2; or figure 2 in patent application US2004/0100945 A1.

Sometimes, you can even find directed graphs with multiple paths to show the flow of communication, as figures 2, 3a, 3b, 4a, 4b in Hughes Aircraft Company patent US5485464.


I would expect that a drawing that conforms to USPTO drawing requirements (black and white comes to mind, exceptions for color is accepted only under documented conditions). A search of patents.google.com would produce the examples provided by user=David.

If you suspect that something is prohibited, searching the relevant USPTO requirements (in this case drawings) is the 'do it yourself' method of determining eligibility. One has to be careful using precedence in the sense that the rules are changing: in theory changes in rules will be documented in the updated requirements. This response is not to discourage one from answering the question. It is intended to generalize the process and approach solving this class of problem.


Diagrams, illustrations, photos and graphs are all allowed in a patent application. They are referred to as drawings under 35 U.S.C 113:

The applicant shall furnish a drawing where necessary for the understanding of the subject matter sought to be patented.

Note from the U.S.C clause above that the purpose of any drawing is only to facilitate the understanding of the subject matter that one is trying to patent.

Within the context of an utility patent, only the Claims are protected under the U.S. Patent Act.

Therefore, if the said diagram illustrates the method/process that one is trying to patent, the sequential steps of the diagram must be incorporated in the Claims themselves.

FiG.2 of US20120287823A1 shows a similar diagram.

  • What do you mean by "steps of the diagram must be incorporated into the Claims"? Is it not rather that they must be mentioned in the detailed description -section? I think there are many patents like patents.google.com/patent/US6675196B1/en?oq=US6675196 where the content of the claims is rather small compared to the content of the diagrams. In that patent for example the claims do not refer to elements including the "steps" of the diagrams
    – Panu Logic
    Commented Feb 17, 2019 at 18:35
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    @PanuLogic Let me attempt to explain to the best of my ability without obfuscating the issue. Firstly, diagrams and/or drawings are allowed. They are helpful but not obligatory. My response was to draw minime's attention to the following: 1) only the Claims are protected under the U.S. Patent Act. In most cases, 2)the diagrams/drawings are furnished for the understanding on the subject matter. In another words, 3) Diagrams/drawings are included only to help examiners and readers to understand the claims. Please do seek patent counsel for further understanding. I am speaking from experience.
    – Kane Chew
    Commented Mar 9, 2019 at 4:29

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