Chapter §16.02 Literal Infringement

• Jurisdiction: United States

§16.02 Literal Infringement

Literal infringement is found where the accused subject matter falls clearly within the express boundaries of the properly interpreted claim.⁴ For example, consider a claim that recites

1. A composition of matter comprising 20–30 percent component X by weight.

If the accused composition includes 25 percent component X, then claim 1 is literally infringed.⁵ If the accused composition includes only 15 percent X, however, claim 1 is not literally infringed.⁶

One might expect instances of literal infringement to be relatively rare, assuming that patent claims provide clear, advance notice to competitors of what is and is not permissible imitation. Competitors could reasonably be expected to read the claims and plan their activities accordingly so as to avoid literal infringement. As the Supreme Court has recognized, "[o]utright and forthright duplication is a dull and very rare type of infringement."⁷

In practice, instances of literal infringement are quite common. This follows from the uncertainty of claim interpretation, that is, the pre-litigation ambiguity of the literal scope of the claims. Despite the aspirational goal that patent claims should provide clear, advance notice of the literal scope of the patentee's exclusionary right, as well as the statutory presumption that the claims of an issued patent comply with the definiteness requirement of 35 U.S.C. §112(b), the meaning of one or more...