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© Michael A. Shimokaji, 2014

PATENT CLAIM INFRINGEMENT CHARTS –

WHAT ARE THEY & WHY YOU NEED THEM

If you are considering initiating a patent infringement lawsuit, or

getting ready to defend against one, you will hear the term “claim chart.”

A claim chart is a tool to evaluate potential patent infringement. It is a

tool used by attorneys representing a patent owner considering the possibility

of filing suit against an infringer. It is also used by attorneys representing an

alleged patent infringer. A typical claim chart might have the following

format:

Claim 1 Infringing Product

A tool for turning a screw,

comprising:

Picture of overall infringing product

a handle; and Picture of handle of infringing

product

a blade attached to the handle Picture of blade of infringing

product

Michael Shimokaji

www.shimokaji.com

949-788-9968

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© Michael A. Shimokaji, 2014

The claim chart might include all claims of the patent, or perhaps just the

independent claims. It may only include a representative claim when there

are many claims in the patent.

The claim chart breaks down a single claim by its individual claim

elements. For each claim element, information (such as a picture from an

advertisement) about the infringing product is obtained that establishes (or not

establishes) that the infringing product has the claim element. For

infringement to exist, all elements in a given claim must be found in the

infringing product.

For example, in the above sample chart, the claim requires that a blade

be attached to a handle. Opposite to that claim element in the chart, the picture

of the infringing blade may or may not show the blade attached to the handle.

If not attached, one may conclude there is no infringement. If it is attached,

one may conclude there is infringement.

What the claim chart seeks to accomplish is avoiding the hasty

conclusions by a patent owner that “it’s obvious the product infringes” or by

the alleged infringer that “it’s obvious our product is different from the patent

owner’s product.” The claim chart puts the question of infringement in “black

and white” terms and enables the question to be answered in a systematic

fashion.

But the claim chart is only as good as the details in it. Some claim

charts are prepared without all of the claim language in the chart. If not all of

the claim language is present, one cannot accurately assess the presence or

absence of infringement.

Another deficiency that can exist in a claim chart is when the claim

elements are described in one long paragraph so that details in the claim

elements become obscured. As an example, the above sample claim may have

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© Michael A. Shimokaji, 2014

been written in a single sentence – “a handle and a blade attached to the

handle.” In a situation where the claim might have several hundreds of words,

individual words can be overlooked, though they might be significant to the

question of infringement.

Attorneys for patent owners and alleged infringers may also want claim

charts to meet their ethical and legal obligations. Attorneys have an obligation

to avoid asserting claims or defenses in the absence of a good faith belief that

the claim or defense is supported by the facts and law. Claim charts enable

attorneys to meet that obligation.

PRACTICE POINTER:

While a patent owner or alleged infringer might be in a rush, or may be

reluctant to spend the money on claim charts, they are a useful tool to evaluate

the strength or weakness of one’s position. As such, claim charts can help

avoid expenses if one’s position is determined to be weak. They can help just

incurring expenses when one’s position is determined to be strong.