By: Mel R. Quintos

In this newsletter, we see how the U.S. Court of Appeals for Federal Circuit (CAFC) has recently applied the doctrine ofclaim differentiation in its July24, 2009 decision o f Orenshtyn v. Citrix Systems, Inc. However, prior to a discussion of the Orenshtyn case, we first define what this doctrine means.

In the 1987 case of Tandon Corporation v. United State International Trade Commission, the CAFC defined the doctrine of claim differentiation as follows:

• There is presumed to be a difference in meaning and scope when different words or phrases are used in separate claims. To the extent that the absence of such difference in meaning and scope would make a claim superfluous, the doctrine ofclaim differentiation states the presumption that the difference between claims is significant. [Emphasis added.]

In line with this doctrine, the court later said in the 2004 case of Liebel-Flarsheim Co. v. Medrad, Inc. that „[t]he presence of a dependent claim that adds a particular limitation raises a presumption that the limitation in question is not found in the independent claim.“–click here to read more—