
Defendants often want to import limitations from the specification to the claims. It only takes one missing claim element per claim to defeat an allegation of patent infringement (setting aside DOE). And the language of patent specifications is often narrower than the claims themselves, providing ample opportunities to find limitations.
Federal Circuit precedent, of course, says that the Court should avoid importing limitations from the specification into the claims—but using the specification to interpret the meaning of a claim is OK. Phillips v. AWH Corp., 415 F.3d 1303, 1323 (Fed. Cir. 2005). As countless courts have recognized, that is a fine line.
As a result, defendants' early-case strategy often …