The difference between “i.e.” (id est, “that is”) and “e.g.” (exempli gratia, “for example”) comes up in patent cases from time to time.  While the difference is not always clear to some practitioners, it is clear to the Federal Circuit.  Recently, in Rembrandt Wireless Technologies, LP v. Samsung Electronics Co., Ltd., [2016-1729] (April 17, 2017), the Federal Circuit held that patentee’s use of i.e. during prosecution was definitional, finding that “two types of modulation methods, i.e., different families of modulation techniques” defined “two types” as involving different families of modulation techniques.  The Federal Circuit noted precedent where i.e. was treated as definitional:

A patentee’s use of “i.e.,” in the intrinsic record, however, is often  definitional.   Edwards Lifesciences LLC v. Cook Inc., 582 F.3d 1322, 1334 (Fed. Cir. 2009) (“[U]se of ‘i.e.’ signals an intent to define the word to which it refers.”); see also Abbott Labs. v. Novopharm Ltd., 323 F.3d 1324, 1330 (Fed. Cir. 2003) (holding that a patentee “explicitly defined” a term by using “i.e.” followed by an explanatory phrase).

The Federal Circuit explained that “the term ‘i.e.’ is Latin for id est, which means ‘that is.’”  The Federal Circuit added that whether a statement to the PTO that includes “i.e.” constitutes a clear and unmistakable disavowal of claim scope depends on the context, citing Braintree Labs., Inc. v. Novel Labs., Inc., 749 F.3d 1349, 1355 (Fed. Cir. 2014).

Samsung pointed to instances were i.e. was found not to be definitional, such as where it would be internally inconsistent as in Pfizer, Inc. v. Teva Pharm., USA, Inc., 429 F.3d 1364, 1373 (Fed. Cir. 2005) or where it would read out preferred embodiments, as in Dealertrack, Inc. v. Huber, 674 F.3d 1315, 1326 (Fed. Cir. 2012).  But the Federal Circuit did not agree that interpreting “i.e.” as definitional, as it normally is, would result in inconsistency.

The difference between i.e. and e.g. was highlighted by the Federal Circuit in Interval Licensing LLC v. AOL, LLC., [2013-1282, -1283, -1284, -1285] (September  10, 2014).  In considering the definiteness of the claim limitation “unobtrusive manner that does not disturb the user,” the Federal Circuit noted that:

Had the phrase been cast as a definition instead of as an example — if the phrase had been preceded by “i.e.” instead of “e.g.” — then it would help provide the clarity that the specification lacks.  But as the specification is written, we agree with the district court that a person of ordinary skill in the art would not understand the “e.g.” phrase to constitute an exclusive definition of “unobtrusive manner that does not distract a user.”

The Federal Circuit said that given a lone example, rather than a definition, a skilled artisan is still left to wonder what other forms of display are unobtrusive and non-distracting.  The Federal Circuit concluded that the phrase “unobtrusive manner that does not distract a user” was indefinite.