Daimler AG's Mercedes-Benz unit won a U.S. lawsuit that accused the carmaker of infringing a patent for a monitor to detect when a motorist is drowsy.
The patent, owned by licensing company Ibormeith IP LLC, is invalid, U.S. District Judge Faith Hochberg ruled Sept. 5 in federal court in Newark, N.J.
She said the patent owner never clearly described what the invention claimed to cover.
The lawsuit, filed in October 2010, targeted the Mercedes Attention Assist feature used in the E-Class and some S-Class vehicles.
The feature monitors a driver's behavior at the start of a trip and develops a profile for comparison throughout the journey.
If the pattern alters, an alarm is sounded suggesting the driver take a break. Patent law requires inventors to describe, in definite terms, the scope of their invention, much like a landowner must explain his property borders so others know where to avoid.
While the Ibormeith patent claims to cover an algorithm to compute the changes in a driver, it "fails to disclose the steps necessary to actually perform that suggested algorithm," Hochberg ruled.
Patents are rarely ruled indefinite, according to a statement today by Shearman & Sterling LLP, the law firm that represented Daimler in the case.