When Claim Charts Do More Harm Than Good For Patent Litigation and Licensing

When Claim Charts Do More Harm Than Good For Patent Litigation and Licensing

Copperpod IP
7 min readFeb 2, 2024

Fig: Sample Claim Chart

What is a Claim Chart? — Claim Chart (infringement contention) is one of the most important component in a patent infringement case and is often a legal requirement as per most US District Courts’ local patent rules. Claim charts serve the purpose of giving the Defendants notice of the infringement read, on a limitation-by-limitation basis and eventually become the basis (and exhibits) for the infringement expert report(s) in the case — undergoing multiple iterations as discovery proceeds in the case and new facts are uncovered.

Yet, not all claim charts are born equal — and courts have on several counts punished plaintiffs for not meeting their burden of proof in their claim charts. On even more counts, plaintiffs have found themselves restricted and cornered due to missteps taken right at the beginning of the case when the preliminary infringement contentions were prepared.

Based on an analysis of over 200 cases spanning the last decade, this article provides instances when their claim charts actually do more harm than good in forming, advocating and ultimately proving the patent infringement position in the case:

1. When individual limitations are not discussed.

A claim chart by definition should address how the accused product practices each claim limitation of an asserted claim. A claim chart that maps the accused product to the claim as a whole without addressing individual limitations most likely fails to meet the burden of proof. Further, even if necessary evidence is not publicly available for a particular limitation, it is suicide to just leave the analysis blank. At the very least, the analysis for such a limitation should contain the best-effort evidence and an explanation that the infringement is “upon information and belief” and can/will be proved from proprietary documents/code in due course of fact discovery.

2. When claim limitations are incorrectly separated.

Claim limitations are typically separated by semi-colons. While that is a good thumb rule, it can be more advantageous to separate limitations more granularly. If a particular limitation is lengthy or recites multiple components/steps — it may be easier to address those components individually.

3. When the wrong entity is accused.

Always be cognizant of who actually infringes on the patent claim. Name the correct corporate entity that makes, uses or sells the infringing functionality. Is it the company that makes the product? Is it the company that imports or sells it? Is it the company whose employees use the product — or perhaps is it the end users of that company’s products who actually infringe by using the product? The claim chart language should clearly define who is being accused of infringement and how or when that infringement occurs.

4. When only an exemplary product is charted.

It is not uncommon to see dozens of products being accused in a single lawsuit — we see this particularly in cases involving smartphones/tablets/laptops. It may indeed be unduly burdensome for a plaintiff to chart every single product individually (though that may indeed be a requirement under local rules of certain U.S. District Courts). In those cases, a good strategy is to chart one or a few exemplary products — but the claim charts must clearly mention all the accused products and state that the claim chart cites a particular product as an exemplary infringing product.

5. When incorrect or inconsequential products are charted.

Pay special attention to the product family, model number and variants while charting a product. Marketing material can often be ambiguous and deceptive similar across products of the same family and especially when products are bundled as part of a larger service/product offering. Charting the wrong product will drive the court to quash the claim chart (and the case) altogether and you may not get a second chance to chart the correct product.

In addition, while choosing an exemplary product to be charted, it is a good practice that the most significant of the many accused products is charted. That way if your damages calculation is later restricted by the court to only the products actually charted, the damages fall back to a lower but not laughably lower number.

6. When claim charts have insufficient evidence.

This is a no-brainer — more evidence is most likely better than less evidence. Plaintiffs sometimes do not want to divulge all their cards in a claim chart — and while that may make sense in certain cases (especially before the Markman hearing), our experience has shown that it is better to include as much evidence as we can find in the claim chart, but leave leeway for eventual changes in strategy/theory through comments and disclaimers. In any case, removing content from 500-page claim charts later is much easier than adding new content into them.

7. When the correct source of information is not provided.

Make sure that every piece of evidence you have in the claim charts has a supporting source citation — and in case of hyperlinks, the hyperlinks point to the correct document. In case of webpages, since webpages often change content, it is good idea to also mention the last date on which the webpage was accessed. It is an even better idea to make a PDF of each source document referred to in the claim chart and attached as an exhibit — which can later be submitted along with the claim chart.

8. When evidence does not support the assertion.

It is sometimes tempting to jump to the conclusion before evaluating and analyzing the facts — hoping that in due time the facts will come together and make sense to the reader. While that does indeed happen — it is better to include detailed analysis of why and how the facts lead to the conclusion, and if it happens that the facts are just not sufficient, that can be stated as well. It is much better to have factual gaps than to fill the claim chart with conflicting facts that do more harm than good to the conclusion.

9. When charts do not provide corresponding structure for means-plus-function claims.

Functional claiming has had a checkered past. The current law dictates that means-plus-function limitations must be supported by identification of a “structure” from the patent specifications that performs the claimed function. The “structure” may take the form of physical components, systems, drawings or even algorithms discussed within the patent specifications. Failure to identify sufficient structure for an MPF limitation can lead the court to hold that claim indefinite — hence, it is strongly advised that the claim chart address means plus function language appropriately.

10. When the claim charts do not mention doctrine of equivalents and indirect infringement.

Unless the infringement theory presented in the claim chart is airtight and clear as a day, ensure that the claim chart clearly spells out that to the extent the claims are not infringed literally, they are infringed under doctrine of equivalents. Most people would not explain the equivalents in the claim chart (the equivalence may not be entirely understood before significant fact discovery) — but a statutory statement on doctrine of equivalents pre-empts the argument later that the defendants were not given notice that the plaintiff was going to assert infringement under the doctrine.

The same goes for indirect infringement. For method claims, sometimes the direct infringement may not be company accused of infringement — for example, the direct infringement may only occur when the company’s end users operate the product in certain ways. It is therefore important to analyze and address that the infringement by the company may be direct and/or indirect.

11. When there is no direct infringement of method claims.

The current law states that for an indirect infringement to occur, an act of direct infringement must also have occurred. For example, if Company A sells an infringing product (but never itself performs the infringing act), then Company A can be accused on indirect infringement if and only if somebody, presumably users of the infringing product, actually perform the acts of direct infringement. So if the claim chart does not sufficiently show that actual direct infringement has occurred (by the target company or by any other entity), an indirect infringement argument may not be successful.

12. When over-broad constructions are used for asserting infringement.

Claim terms can sometimes be open to interpretation. For example, a claim may require a “wireless communication network” — which may mean any of IEEE 802.11 wireless LAN, Bluetooth, Zigbee, NFC, 3G/4G telecom networks, satellite radio or any other wireless technology. While the exact scope of a claim term will (hopefully) become clear once the case goes through a Markman claim construction hearing, it may sometimes be beneficial to include the assumed construction at the time of drafting especially for terms that go beyond a “plain and ordinary meaning” and where there is likely to be dispute later in the case. It further shows that the plaintiff has reasonable basis for its infringement theory.

13. When the analysis is cryptically referenced.

For patents with a number of infringed claims, it is often tempting to stuff all the evidence and analysis up in the first few claims and then keep referring to those claims when dealing with the subsequent claims. While that is a nice shortcut and makes the claim charts easier to read — that advantage exists only as long as the claim charts are in draft form. Once the claim chart goes out to the defendant, it is advisable that each claim limitation has its own analysis and evidence — since claims often get dropped in due course of the litigation, and so if a particular claim (with the evidence) is dropped in favor of later (that references the earlier claim), it gets unnecessarily cumbersome to put back the evidence in the later claim at such a later stage. Nevertheless, if that is a risk you are willing to take (and many do), make sure that the references only travel in one direction — up. For example, claim 10 should refer back to claims 1–9 — and not claim 11–50. Even worse would be if certain claims in the chart refer upwards and others refer downwards. Not only would the claim chart be cumbersome to read but it would be a nightmare to supplement or use for the purposes of an expert report.

Note: Copperpod IP conducts deep technical analysis and helps attorneys substantiate infringement arguments with detailed evidence of use (EoU) reports, claim charts and other licensing/litigation artifacts — while reducing the overall cost of enforcement. Contact Us to know more!

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Copperpod IP

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