Patent Claim Construction — The Means Don’t Justify the Means

The Means Don't Justify the MeansErgo Licensing, LLC v. Carefusion 303, Inc., No. 2011–1229 (Fed. Cir. Mar. 26, 2012) (Judges Newman, Linn, and Moore)

Means-plus-function claims can be tricky. A means-plus-function limitation lets a patentee claim a structure by describing its function, like a “means for attaching a door to a wall” or a “means for containing liquid,” instead of “hinge” or “bottle.” The structure of a means limitation isn’t in the claim, so it has to be disclosed in the specification. When a computer is part of that structure, it’s not unusual for patentees to omit algorithms if someone skilled in the art would know what to do. But that can be a problem later, as this case shows.

Ergo sued CareFusion for patent infringement. Ergo’s patent is directed to an infusion system to meter and deliver fluids from multiple sources into a patient. Each fluid is metered separately by a “programmable control means.” The district court held that the terms “control means” and “programmable control means” in Ergo’s patent were indefinite and granted summary judgment of invalidity.

Ergo took the position that the “control means” was the same as a general-purpose computer. It argued that even though there are no control algorithms in the patent, someone of ordinary skill would know how to make a “control means.” The Federal Circuit agreed with the district court that that’s not enough. It doesn’t matter if someone skilled in the art would understand what to do—you still have to disclose an algorithm. It affirmed the district court’s judgment of invalidity for indefiniteness.

Judge Newman dissented. She argued that the Ergo’s claims are no different from the claims in thousands of other patents. She even pointed out that CareFusion has a patent with the same sort of means-plus-function claim with no algorithm disclosed. She expressed concern that this decision now casts the validity of all sorts of patents into doubt.

There are a couple of lessons here. First, if you haven’t already, you may want to rethink your use of means-plus-function claims. But if you want to use them anyway, make sure you have some algorithm disclosed for any “means” that requires a specially programmed computer. Otherwise, the patent may run into trouble if it’s ever enforced.

Photo credit: Sean Michael Ragan

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