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     It might seem that stretch film and gym equipment heart rate monitors have nothing at all in common. Both products, however, were at the heart of two seminal patent cases which, going forward, will define the law of “indefiniteness” as it relates to patent claims.


Parking restrictions should be (but in Los Angeles rarely are…) clear and definite so that we can be sure about our chosen parking spot. Similarly, companies need to know the boundaries of others’ patent claims so that they can plan their business strategies accordingly.  In the Nautilus case, the Supreme Court found  the Federal Circuit’s existing test for indefiniteness to be unworkable.

The first of the two cases, Nautilus v. Biosig Instruments, began winding its way through the courts as the second case- Dow Chemical v. Nova– was brewing. In the Nautilus case, Biosig claimed that Nautilus had infringed its patents covering heart rate monitors.  The monitors are embedded in the handlebars of gym equipment and are spaced from one another. The patent-at-issue disclosed and claimed that the monitor electrodes were mounted in a “spaced relationship with each other.” Nautilus  claimed that the patent was unenforceable because the spacing limitation was too vague. Biosig, on the other hand, claimed that an engineer skilled in the art would be able to determine the correct configuration by trial and error.

     Nautilus had prevailed in the district court, but the Court of Appeals for the Federal Circuit reversed the trial court’s decision. The case was appealed to the U.S. Supreme Court and the court accepted the case in order to clarify the law of indefiniteness, which was itself a somewhat vague concept. For example, at the time, the appeals court analyzed indefiniteness in terms of whether a claim is or is not “amenable to construction” or “insolubly ambiguous.”

     The Supreme Court, however, considered the appeals court’s test itself to be too vague, noting that it “can leave the courts and patent bar at sea without a reliable compass.”  The Court’s solution was a new test, namely:

A patent is indefinite if its claims fail to inform with reasonable certainty, those skilled in the art, about the scope of the invention.

     (If you’re interested in hearing the oral argument (or reading the transcript) from Nautilus, it can be found here, courtesy of Chicago-Kent College of Law, the written decision can be found here).

At the time the Supreme Court decision in Nautilus came out, the Dow Chemical case had made its way to the Court of Appeals for the Federal Circuit.  Leading up to the appeal, Nova (defendant in the Dow case) had really taken a beating. In particular, Nova had lost multiple cases against Dow and and had paid it over 100 million in lost profits and royalties. 

     The Supreme Court’s decision in Nautilus, however, was a game changer and Nova used the case to argue before the Circuit Court that Dow’s patent claims were indefinite. Nova and Dow both make ethylene polymer compositions, which are a type of plastic film. One important aspect of the type of polymers at issue in the case is their ability to retain their strength when the gauge (i.e. thickness) is decreased. The claim terms at issue had to to with describing certain characteristics of the polymer, such as how it performed under under strain.

  In light of the Nautilus decision, Nova argued that Dow’s claim limitation stating that polymer displacement in response to strain (or “slope of strain hardening coefficient”) be “greater than or equal to 1.3” was indefinite. Unfortunately for Dow, the court found that the slope of strain hardening could be calculated in four different ways, each of which will give a different result. 

     The Federal Circuit reversed its earlier decision in Nova, in light of the new test for indefiniteness from Nautilus:

We conclude that our prior decision is not binding on the issue of indefiniteness because  Nautilus changed the applicable law.

    Surprisingly, though, the same hadn’t happened in the Nautilus case. In that case, on remand from the Supreme Court, the Court of Appeals for the Federal Circuit didn’t find that Biosig’s claims were indefinite- notwithstanding the change in the law.