“E.g.” vs. “i.e.” and the definiteness requirement

The plaintiff in Interval Licensing LLC v. AOL, Inc. tried to persuade the U.S. Court of Appeals for the Federal Circuit to use a “narrow example” in the patent’s written description to define the phrase “unobtrusive manner.” The court acknowledged that a patent that defines a claim phrase may satisfy the definiteness requirement but declined in this case to cull out a single “e.g.” (“for example”) phrase from a lengthy written description to serve as the exclusive definition of a subjective claim term.

Notably, the Federal Circuit said that, if the example had been cast instead as a definition — in other words, had it been preceded by “i.e.” (“that is”) rather than “e.g.” — the clarity that the patent specification lacked would have been provided. As written, though, the patent’s example created ambiguity that fell within the “innovation discouraging” zone of uncertainty that the U.S. Supreme Court has warned against.

For more on the Interval case, click here.