The Limits of Claim Differentiation

Berkeley Tech. Law Journal, Vol. 22, p. 1389, 2007

Stanford Public Law Working Paper No. 1008885

16 Pages Posted: 23 Aug 2007 Last revised: 5 Dec 2014

Date Written: August 22, 2007


The process of claim construction - determining the meaning of patent claims - is the most important part of patent litigation. There are a number of rules or canons that courts can use in applying the interpretive sources to reach an understanding of what patent claims mean. The canon that has arguably had the most significant impact on claim construction is the doctrine of claim differentiation. The claim differentiation doctrine in its broadest reading provides that no two claims in the same patent should be interpreted to cover the same thing.

As a general matter, applying the doctrine of claim differentiation results in broader constructions of patent claims, because it is most commonly used to prevent defendants from limiting a broad genus claim to the range of embodiments actually disclosed or more explicitly recited in other claims. Sometimes this is the right result, because defendants are improperly seeking to limit broader genus claims to the preferred embodiments disclosed in the specification. But at other times it leads to problematic results.

In this article, I conduct an empirical review of claim differentiation decisions in the Federal Circuit and in the district courts, and I suggest limiting principles that can be used to distinguish good uses of the doctrine from bad.

Suggested Citation

Lemley, Mark A., The Limits of Claim Differentiation (August 22, 2007). Berkeley Tech. Law Journal, Vol. 22, p. 1389, 2007, Stanford Public Law Working Paper No. 1008885, Available at SSRN:

Mark A. Lemley (Contact Author)

Stanford Law School ( email )

559 Nathan Abbott Way
Stanford, CA 94305-8610
United States

Here is the Coronavirus
related research on SSRN

Paper statistics

Abstract Views
PlumX Metrics