What is an Evidence of Use Claim Chart & How do Create One?  

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Evidence of use patent claim charts

Patent claim charts are used to show that a patent has been used. The use of the chart indicates that the inventor made the invention, which can be used for commercial purposes. To prove this, you will need to show how your invention works or what it does. This is done by providing evidence of how products were manufactured or sold using your invention.

What is the EOU claim chart?

EOU charts are used to determine whether a patent claim is infringed, invalid or enforceable. An EOU chart shows all possible combinations of elements in a claim and their corresponding scope of protection under the doctrine of equivalents (DOE). The chart can be constructed by hand or a patent claim chart generator such as PatentEngine.

Types of EOU patent claim charts

EOU charts are used to show that a patent is valid.

EOU charts are used to show that a patent is not valid.

EOU charts are used to show that a patent is invalid.

EOU charts are used to show that a patent is not invalid

Importance of Claim Charting

Claim charting is useful for both the owner of the patent as well as the investors/ buyers for a better understanding of the scope of the patented claim. It can be conducted for a single patent as well as a portfolio of patents.

Furthermore, EOU helps patent owners identify potential infringement vs likely infringement after scrutinizing the patent claim of the patent invention in question. 

For the investors, this EOU analysis helps understand the scope of infringement of a potential patent, identify how patent claims can be commercialized, patent licensing, and the like.

Advantages of Evidence of use patent claim charts

Following are a few advantages of Evidence of use patent claim charts

Knowledge of the market

The analysis provides knowledge about the potential infringement of the patented product. This helps in analyzing the right target companies in the market in which there is a scope for improvement. Further, how the patent invention relates to the suspected product and to identify the future market for it, the claim charting is prepared. This will further attract the big companies to invest in the patent and to make their IP stronger.

Identification of potential patent infringements 

The analysis helps in analyzing patent portfolios and listing down the top players that can potentially be infringed upon.

Invalidate a patent

Claim charting can also be used to prove that a patent is invalid by showing that it is the same as something already known in the literature. Other advantages of this analysis include patent licensing, patent sales, identifying products and services/standards that are suspected to be infringing the patented product, and improving patent portfolios.

Process of Evidence of Use Claim Charting  

Claim charting analyzes each claim of a patented product by breaking it up into elements or limitations and then presenting the evidence in a form of a graphical representation. This determines the value of the patent. To further improve claim charts, the process of EOU maps every individual patent element, such as the product literature, product terms, patents, figures, etc., to the corresponding features of products and services.

Preparing EOU chart

The EOU chart is a visual representation of the claims in a patent application. The EOU chart shows the claim elements, the claim limitations, and the support for each claim element or limitation. The EOU chart prepares a patent application by identifying all possible alternatives and selecting one or more that best describes your invention.

Commonly used methods in preparing EOU chart

When developing an EOU chart, several methods can be used. Patent attorneys commonly use these methods when preparing the chart:

The first method is called the “textual comparison method.” In this method, you will compare each element of your patent claim with each element in the prior art reference(s) and see if there is any difference between them. If there’s no difference at all between two things then they might be considered identical or indistinguishable from one another.

The second common way to develop an EOU chart is by using flow charts or graphs. With this approach, you draw out all possible combinations between elements within your claim and prior art references so that it becomes easier for others to understand what may overlap between these two areas respectively if indeed they do overlap at all!

Process of finding potentially infringing products

The process of finding potentially infringing products starts with the search for the subject patent by preparing a claim chart using the technical standard specifications. This is followed by the identification of similar products that are suspected to be using the patented technology, then the patent claim mapping of the suspected products with the claimed independent elements is done. Finally, results in the form of graphical representation are produced.


The EOU chart is a very powerful tool that can help you in defending your patent from an infringement claim. It is important for every investor to know about its existence and how it works. You should always consult with an expert patent attorney if you are unsure about anything related to the preparation of the EOU chart or any other patent-related matter.

Our team of advanced patent attorneys assists clients with patent searches, drafting patent applications, and patent (intellectual property) agreements, including licensing and non-disclosure agreements.

Advocate Rahul Dev is a Patent Attorney & International Business Lawyer practicing Technology, Intellectual Property & Corporate Laws. He is reachable at rd (at) patentbusinesslawyer (dot) com & @rdpatentlawyer on Twitter.

Quoted in and contributed to 50+ national & international publications (Bloomberg, FirstPost, SwissInfo, Outlook Money, Yahoo News, Times of India, Economic Times, Business Standard, Quartz, Global Legal Post, International Bar Association, LawAsia, BioSpectrum Asia, Digital News Asia, e27, Leaders Speak, Entrepreneur India, VCCircle, AutoTech).

Regularly invited to speak at international & national platforms (conferences, TV channels, seminars, corporate trainings, government workshops) on technology, patents, business strategy, legal developments, leadership & management.

Working closely with patent attorneys along with international law firms with significant experience with lawyers in Asia Pacific providing services to clients in US and Europe. Flagship services include international patent and trademark filingspatent services in India and global patent consulting services.

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