Means-Plus-Function Limitations Are Indefinite Under 35 U.S.C. § 112, ¶ 2 Where A Specially Adapted Computer Is Required, But Patent Does Not Disclose Algorithm

This article previously appeared in Last Month at the Federal Circuit, April 2012

Judges: Newman (dissenting), Linn, Moore (author)

[Appealed from D. Me., Judge Singal]

In Ergo Licensing, LLC v. Carefusion 303, Inc., No. 11-1229 (Fed. Cir. Mar. 26, 2012), the Federal Circuit affirmed the district court's holding that the terms "control means" and "programmable control means" are indefinite because the patent specification failed to disclose any corresponding structure.

Ergo Licensing, LLC ("Ergo") accused Carefusion 303, Inc. ("Carefusion") of infringing claims of U.S. Patent No. 5,507,412 ("the '412 patent"), which relates to an infusion system used to meter and deliver fluids from multiple fluid sources into a patient's body. The infusion system includes adjusting means for controlling the fluid flow from the multiple fluid sources. Prior to the Markman hearing, the parties stipulated that several terms were means-plus-function terms, including the terms "programmable control means" and "control means." The asserted claims recited "programmable control means coupled with said adjusting means for controlling said adjusting means," and the parties also agreed that the function of each of the terms is "controlling the adjusting means." The district court held that the "control means" terms were indefinite for failure to disclose corresponding structure, and Ergo appealed.

On appeal, the Federal Circuit explained that 35 U.S.C. § 112, ¶ 2 requires that a patent specification "conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." The Court further explained that § 112, ¶ 6 provides that an applicant may express an element of a claim "as a means or step for performing a specified function . . . and such claim shall be construed to cover the corresponding structure . . . described in the specification and equivalents thereof." In exchange for the ability to use the means-plus-function language, a patent applicant must indicate what structure constitutes the means for performing the function. If an applicant does not disclose structure for a means-plus-function term, the claim is indefinite.

"[A] general-purpose computer is sufficient structure if the function of a term such as 'means for processing' requires no more than merely 'processing,' which any general-purpose computer may do without special programming. If special programming is required for a...