Nautilus Inc. v. Biosig Instruments Inc. involves U.S. Patent No. 5,337,753 for a heart-rate monitor.
The ‘753 patent covers a monitor mounted on exercise equipment (such as an exercise bicycle, treadmill, or elliptical trainer). The user’s hands each contact a live electrode and a common electrode on the handles. The patent doesn’t specify the distance between the electrodes, merely requiring that they be in a “spaced relationship.”
Biosig originally sued Nautilus in 2004, claiming that Nautilus’s exercise equipment included the device covered by the ‘753 patent. Nautilus responded with a motion for summary judgment seeking a ruling that the patent was invalid on the grounds that the “spaced relationship” claim was indefinite.
A federal district court agreed and granted Nautilus’s motion.
However, the Federal Circuit (which specializes in patent cases) held that the “spaced relationship” claim was sufficiently definite, even though there was no specification of how wide the spacing should be.
The Federal Circuit held that the term “spaced relationship” was not indefinite because people with normal skills and knowledge in the technical field, reading the patent and looking at its drawings, would understand what the term meant.
For example, since claim 1 of the patent required the electrodes to detect signals at two points on the user’s hand, the distance between the electrodes could not be greater than the width of a typical user’s hand.
The Federal Circuit noted that even though a person “skilled in the art” might have to experiment to determine the scope of the claim, that didn’t make the claim indefinite, as long as the amount of experimentation required was not “undue.”
Nautilus challenged the Federal Circuit’s standard as “overly permissive” and appealed to the Supreme Court, saying that the decision would encourage inventors to make their claims unclear, thereby requiring federal judges to waste time making sense of such claims.
The Electronic Frontier Foundation has filed a brief in support of Nautilus, saying “a more sensible rule would help reduce abusive [patent] litigation.”